disclaimer - seoul national...

저 시-비 리- 경 지 2.0 한민

는 아래 조건 르는 경 에 한하여 게

l 저 물 복제, 포, 전송, 전시, 공연 송할 수 습니다.

다 과 같 조건 라야 합니다:

l 하는, 저 물 나 포 경 , 저 물에 적 된 허락조건 명확하게 나타내어야 합니다.

l 저 터 허가를 면 러한 조건들 적 되지 않습니다.

저 에 른 리는 내 에 하여 향 지 않습니다.

것 허락규약(Legal Code) 해하 쉽게 약한 것 니다.

Disclaimer

저 시. 하는 원저 를 시하여야 합니다.

비 리. 하는 저 물 리 목적 할 수 없습니다.

경 지. 하는 저 물 개 , 형 또는 가공할 수 없습니다.

http://creativecommons.org/licenses/by-nc-nd/2.0/kr/legalcode

http://creativecommons.org/licenses/by-nc-nd/2.0/kr/

이 학 석 사 학 위 논 문

Mechanically Coupled Molecular Rotors

Built with Bis(triazolo)benzene Scaffolds

기계적으로 상호 연관된

분자 운동을 하는 비스트리아졸벤젠

2018년 8월

서울대학교 대학원

화학부 유기화학 전공

김 도 담



By

Dodam Kim

Supervisor: Prof. Dongwhan Lee

A Thesis for the M.S. Degree

in Organic Chemistry

Department of Chemistry

Graduate School

Seoul National University

August, 2018

이 학 석 사 학 위 논 문



기계적으로 상호 연관된 분자 운동을 하는 비스트리아졸벤젠

지도교수 이 동 환

이 논문을 이학석사학위논문으로 제출함

2018년 8월

서울대학교 대학원

화학부 유기화학 전공

김 도 담

김도담의 석사학위 논문을 인준함

2018년 8월

위 원 장 최 태 림 (인)

부 위 원 장 이 동 환 (인)

위 원 이 홍 근 (인)

i

Abstract



Dodam Kim

Organic Chemistry in Department of Chemistry

The Graduate School

Seoul National University

In this Thesis are described conformationally well-defined synthetic systems named as

“triple-deckers”, which are designed to mimic and better understand the compact

three-dimensional (3-D) structures of biological origin. Key structural features of

these systems include (i) 1,8-substituted naphthalene motif as a “turn” motif to

minimize the number of rotatable bonds, and (ii) bis(triazolo)benzene and aryl

pendant groups to maximize the intramolecular donor–acceptor (D–A) type π–π

stacking. A combination of 1D and 2D (COSY and NOESY) 1H NMR, and X-ray

crystallographic studies established the presence of strong non-covalent interactions

that are reinforced by a parallel arrangement of aromatic π-stacks. Dynamic NMR

studies by variable-temperature (VT) measurements on a series of double- and triple-

decker π-stacks provided detailed mechanistic understanding of the molecular motions

ii

that can be controlled by electronic and steric factors to control the energetics of site

exchange. We also found that the light-emitting properties of triple-decker molecules

vary significantly as a function of the aryl pendant group, and this property can best be

explained by through-space charge-transfer (CT). Moreover, structural folding

through π-π stacking responds sensitively to the solvent polarity, and temperature-

dependent changes in fluorescence efficiency become more pronounced for systems

that undergo large structural changes between folded (= stacked) and unfolded (=

unstacked) conformations. From these studies emerges a coherent mechanistic

model that relate the structure, dynamics, and photophysical properties of

spontaneously folding synthetic molecules.

Keywords: conformational switching • bis(triazolo)benzene • biomimetic • charge

transfer • fluorescence • NMR

Student Number : 2015-22608

iii

Table of Contents

Abstracts i

I. Introduction 1

II. Results and Discussion 7

II.1. Design and synthesis 7

II.2. X-ray crystallograpy 9

II.3. 1D - and 2D- NMR spectroscopy 11

II.4. Dynamic NMR studies 14

II.5. Solvent-dependent fluorescence studies 20

II.6. Variable-temperature fluorescence studies in polar solvent 23

III. Conclusion 29

IV. Experimental Section 30

References 57

NMR spectra 63

Abstract (in Korean) 80

1

I. Introduction

One of the key non-covalent interactions in biological systems and their synthetic

mimics is π–π stacking.1-5 In natural systems, this interaction occurs in an

intramolecular fashion by robust turn-motifs6 having well-defined directions and

distances7. Restricted torsional freedom of these secondary structures results in limited

dynamics of solution structures, and simplifies the reaction coordinates of

spontaneous folding.

Synthetic systems utilize various backbone motifs to support intramolecular

π–π contacks.8 For example, “comb-like structures” shown in Scheme 1 have rather

flexible backbones with rotatable bonds, and are usually built with aromatic,9

benzofulvene polymers,10 and tetraphenylethenes.11 Since bond rotation is not

restricted, these molecules could adopt various conformations. Such structural

property has been studied for multi-stack systems such as polymers.12

Scheme 1. Select Examples of Comb-Type Structures.10, 11

2

Conformationally more rigid backbones have also been developed by

employing benzene,13 biphenylene,14,15 ferrocene,16-18 anthraquinone,19 and other

structures20-22 (Scheme 2). The advantage of such scaffolds is that they can support

zigzag-type structures as well as comb-like structures, thereby better defining the

relative orientations and spacings between the stacks.

Scheme 2. Select Examples of Rigid Turn-Motif for Zigzag-Type Structures.14, 15, 22

A restriction on rotational freedom enhances conformational stability.23 For

example, aromatic oligoamide β-sheet foldamers reported by Huc exploit substituted

benzenes with intramolecular hydrogen bonding to define rigid turns between

antiparallel π-stacks (Scheme 3).24-28 Restricted torsional motions of the stacked

strands promote good π–π overlap.

3

Scheme 3. Molecular Design Strategies to Enhance Conformational Ridigity of the

Turn-Motif Using Hydrogen Bonding.23, 26

The stability of π–π stack can also be enhanced by donor–acceptor (D–A)

type electrostatic complementarity.29-33 For example, self-assembled D–A aromatic

stacks on metallic surfaces have been observed by STM studies.34 Linear oligomers

have also been reported, in which donors and acceptors are arranged to maximize

intermolecular interactions through folding.32,35-37 As shown in Figure 1, loosely

interacting π-stacks are arranged in an alternating fashion as D–A pairs that are

brought into clos proximity through intermolecular association. However,

intramolecular D–A type π–π interactions through tight aromatic stacking is difficult

to realize due to challenges in synthesis

4

Figure 1. Intermolecular donor-acceptor type interactions to increase the stability of

π–π stacks.38

In the case of 1,8-substituted naphthalenes, the relative orientation and

geometric spacing are ideal for the π–π stacking interactions between the two groups

installed at 1- and 8-position.38-42 Moreover, with only rotatable C–C bonds, it could

serve as a rigid turn motif that allows only restricted torsional motions. Sequential

substitution reactions on the naphthalene 1,8-positions have also been reported.40,41

Despite such advantages, however, the chemistry of naphthalenes has been less

explored, mostly due to the high cost of starting materials and low-yielding synthetic

protocols for structural modification.

Research on the mechanism of electron transfer (ET) by Therien's

porphyrin–bridge–quinone systems revealed that electron donor and acceptor can be

aligned perfectly by using naphthalene scaffold (Figure 2b, 2c).40, 41 Studies on the

charge transfer (CT) process of organic mixed-valence molecules evaluated the

efficiency of through-space CT through naphthalene scaffold (Figure 2a).

5

Figure 2. Previous work using naphthalene as a backbone motif for (a) through-space

CT42 and (b) through-space ET.40 (c) X-ray crystal structure of the compound shown

in (b).41

Substitution at the 1- and 8-positions of naphthalene typically employs cross

coupling reactions.40-42 Recently, directing group-assisted regioselective arylation

protocol has been developed to significantly expand the scope of this chemistry.

Specifically, Qi and co-workers achieved efficient (up to 90% yield) palladium(II)-

catalyzed arylation reactions of naphthylamine derivatives using aryl iodides.43 This

C–H activation methodology was subsequently used in the synthesis of sterically

hindered ligands by Brookhart and co-workers to prepare “sandwich” nickel(II)

catalysts for the synthesis of highly branched polyethylenes.44

As outlined in Figure 3, we have devised a synthetic route that converts

naphthylamines into key structural components of three-dimensional (3-D)

bis(triazolo)benzenes for intramolecular π–π stacking. Bis(triazolo)benzene motif was

initially synthesized by Schmidt and hagenböcker by azo-coupling and oxidative

cyclization reactions.66 This synthetic sequence has widely been used in dye synthesis,

but most of the examples are in patent literature.67 While N1-arylbenzotriazoles are

not emissive,68 the N2-isomers are highly fluorescent.45 Taking advantage of such

photophysical and structural properties, our research group has previously reported

6

turn-on metal sensors,46,47 cascade charge transfer,48 self-assembly,49 and 3-D

triazoliptycenes50.

Figure 3. Design and construction of “triple-decker” molecules via regioselective

arylation of naphthylamines43 and subsequent integration into bis(triazolo)benzene

scaffolds.48

Non-rigid molecules could take many different conformations in solution,

making it difficult to carry out dynamic studies by spectroscopic techniques.51,52 As

shown in Figure 3, however, triple-decker systems are symmetric, and have a finite

number of rotatable bonds. The high modularity in synthesis also allows for

installation of additional spectroscopic handles if needed. As such, they are ideal for

studying molecular motions in solution.

7

II. Results and Discussion

II.1. Design and synthesis of π-decker systems.

A series of double/triple-decker molecules and their models (1–9) were prepared by

taking the synthetic routes outlined in Figure 4. The prototypical triple-decker

molecule 1 was synthesized from 8-arylnaphthylamine in 4 steps in 39% overall yield.

For other systems, yields vary depending on the stability of the synthetic intermediates

(vide infra).

Figure 4. Synthetic routes to π-decker molecules.

8

By taking this modular synthetic routes, both symmetric (1, 3, 6, and 7) and

dissymmetric (2) triple-decker molecules were readily synthesized. with m-

phenylenediamine, a double-decker synthetic intermediate was first prepared by

sequential reaction of azo coupling and oxidative cyclization reactions. Due to its

instability in solution (presumably via C–N bond cleavage), the double-decker

intermediate needed to be carried on to the next step immediately. To stabilize the

double-decker structure, acetylation reaction was thus carried out to produce 5 for

comparative spectroscopic studies (vide infra). For the double-decker intermediate

with electron-rich aryl pendant group, the decomposition reaction was even faster. To

synthesize desymmetrized triple-decker, such as 2, m-phenylenediamine was reacted

sequentially with tolyl- and N,N-dimethylarylnaphthylamine, not the other way

around.

9

II.2. X-ray crystallographic studies

To confirm the chemical connectivity and investigate 3-D spatial arrangements, X-ray

crystallographic studies were carried out. Single crystals of 1, 3, and 7 were obtained

by diffusion of pentane into the CH2Cl2 solution samples of each material. Details of

the crystallographic information are provided in the APPENDIX. In the solid-state

structure of 1 having crystallographic C2-symmetry, dihedral angles of 64.15° and

73.99° were determined across the Cnaphthyl–Ctolyl and Cnaphthyl–Ntriazole bond, respectively.

A centroid-to-centroid distance of 3.31 Å was observed between the cofacially stacked

tolyl and triazole ring, which supports the presence of an intimate π–π contact. As

shown in Figures 5b and 5c, triazole rings are fully covered by the tolyl pendants,

which are placed directly above and below the bis(triazolo)benzene plane in the

middle. Additionally, a triazole ring was fully covered by an aryl pendant ring in

Figure 5b,c. Similar observations were made for the X-ray structures of 3 and 7

(Figures 5d and 5e). In sum, triple-decker molecules adopt compact 3-D arrangements

in the solid-state to maximize the number of structure-stabilizing π–π contacts.

10

Figure 5. (a) ORTEP diagram of 1, (b) Space-filling, and (c) capped-stick (overlaid

with space-filling) models constructed with crystallographically determined atomic

coordinates, (d) ORTEP diagram of 3, (e) ORTEP diagram of 7.

11

II.3. 1D- and 2D-NMR spectroscopic studies

Figure 6. 1H NMR spectra of triple-decker (1 and 3) and double-decker (5) molecules,

along with truncated model (4) in CDCl3 (T = 25 ˚C).

Shown in Figure 6 are the 1H NMR spectra of compounds 1, 3, 4, and 5 obtained in

CDCl3 at T = 25 ˚C. Intriguingly, 1 displayed two unusually broadened (FWHM = 14–

24 Hz) proton resonances at δ = 6.44 and 6.87 ppm, along with typical aromatic

signals of naphthalene and bis(triazolo)benzene moieties at δ = 7.10–8.10 ppm. To

assign the aromatic proton resonances, 2D NOESY experiment was carried out for 1.

As shown Figure 7, key correlations were observed between the singlet at 1.56 ppm

and broadened resonance at 6.44 ppm. Based on the X-ray structure (Figures 7a and b),

the methyl protons of 1 are anticipated to have a strong NOE correlation with the H1

proton. We thus assigned the δ = 6.44 ppm resonance to H1. In support of this

interpretation, the H2 proton resonance at δ = 6.87 ppm is coupled only with the

12

naphthyl proton. Using this information, the aromatic proton resonances of 5 were

fully assigned as well.

Figure 7. (a) 2D NOESY 1H NMR spectra of 1 in CDCl3 (T = 25 ˚C), (b) Spatial

arrangement of the aromatic groups, and key internuclear distances determined by

single-crystal X-ray crystallography (see Figure 5), (c) 2D COSY 1H NMR spectra of

1 in CDCl3 (T = -40 ˚C)

Due to the shielding from aromatic ring current of the adjacent triazole

groups, upfield-shifted proton resonance were observed at δ = 6.10–7.10 ppm for the

tolyl groups of 1, 3, and 5. Unlike 1, however, sharp aromatic resonances were

observed for 5 at the same temperature. For the ring-expanded triple-decker 3, the

tolyl proton resonances appear as four well-separate yet still broadened (FWMW =

28–48 Hz) signals, indicating that each of these protons is placed in magnetically

different environments and exchange slowly on the NMR timescale.53 We thus

decided to carry out variable-temperature (VT) NMR studies to better understand the

13

molecular mechanisms of this intriguing dynamic behavior in solution, which X-ray

crystallography cannot capture.

Figure 8. Variable-temperature 1H NMR spectra of 1 in CDCl3 (T = -40 ˚C to 40 ˚C)

VT 1H NMR studies on 1 (Figure 8) indeed revealed coalescence of the four

doublets resonances as expected H1a, H1b, H2a, H2b at -40 ˚C into two doublets at 40 ˚C.

As shown in Figure 7c, the COSY 1H NMR spectrum of 1 taken at T = –40 ˚C

confirmed that the H1 and H2 protons resolve into (H1a, H1a) and (H2a, H2b) pairs.

14

II.4. Dynamic NMR studies

At least two types of bond-rotating motions should be involved in the chemical

exchange of arylprotons that we observe by NMR spectroscopy: (i) C–C bond rotation

at the naphthyl–tolyl junction; (ii) C–N bond rotation at the naphthyl–triazole junction.

If the C–C bond rotation is the primary reaction pathway, the activation energies of

site-exchange would be similar for 1 and 5.

Equation (1) Gutowsky-Holm equation54 (2) Eyring equation54 (JAB : mutual coupling

constant between nuclei A and B, kc : the rate constant, Tc : the coalescence

temperature, ΔGǂ : the free enthalpy of activation)

Using the Gutowsky-Holm equation and Eyring equation (Equation (1) and

(2)),54 we analyzed the VT-NMR spectra (Figures 8 and 14) to determine the

activation barriers of 14.28 kcal/mol for 1, and 13.51 kcal/mol for 5 (Figure 9).

Apparently, a coupled C–C/C–N bond rotation, rather than C–C rotation alone, is

responsible for the experimentally observed “floor-exchanging” motions, as

schematically shown in Figure 11.

15

Figure 9. Activation energies for the destacking–restacking motions in CDCl3.

The mechanism of floor-exchange, as postulated in Figure 11, involves a

sequence of stacking–destacking–flipping–restacking motions. An intimate contact

between the tolyl and bis(triazolo)benzene π-surfaces is lost upon Cnaphthyl–Ntriazole bond

rotation. Such “destacking” motion alleviates steric constraints around the Cnaphthyl–

Ctolyl junction, which could rotate to exchange the relative positioning of tolyl ortho-

and meta-protons with respect to the bent bis(triazolo)benzene core. Subsequent

“stacking” motions would follow the reverse trajectory to restore the triple-decker

structure. Regardless of the absolute directions of the Cnaphthyl–Ntriazole bond rotating

motions, no two tolyl groups can simultaneously occupy the same “floor”, either top

or bottom, in this mechanically-coupled motion, which is reminiscent of the inner

workings of axle–crank–pedal of a bike.

16

Figure 11. Proposed mechanism of floor exchange of the triple-decker structure.

Based on this mechanistic model, we have devised and implemented

chemical strategies to accelerate or slow down the floor-exchanging dynamics. To

attenuate π–π stacking interactions, bromo-substituted triple-decker 7 was synthesized.

While essentially isosteric (vdW radius of CH3 = 2.00 Å; Br = 1.95 Å)55 4-

bromophenyl is electron-deficient relative to p-tolyl pendants. A lower activation

energy of 7 relative to 1 (Figure 9) thus reflects weaker D–A π-π interactions in the

stacked conformation.

On the other hand, n-butyl substituted triple-decker 6 has an increased

activation energy relative to 1 (Figure 9). A main difference between 1 and 6 is the

steric bulkiness of aryl pendants. Upfield-shifted alkyl resonances of 6 (Figure 6)

indicate that the n-butyl chains extend over to cover the bis(triazolo)benzene core

from above and below, and would thus provide additional steric barrier to slow down

the floor-exchange process.

17

Figure 12. Synthesis of a new polyheterocylcle comprised of triazole and pyridazine

fragments.

Compound 3 was prepared by a hitherto unknown heteroannulation

chemistry of bis(triazolo)benzene, which is reported for the first time here. While a

Diels-Alder and oxidative rearomatization reaction sequence is known,54 a fused

tetracycle comprising triazole and pyridazine fragments has not been reported before.

The chemical structure of this new fluorogenic polyhetroaromatic motif is fully

established by NMR and X-ray crystallographic studies.

We anticipated that the installation of additional nitrogen-rich aromatic ring

would increase the electron-deficient character of the conjugated triazole rings, so that

they engage in stronger D–A π–π interactions. In addition, annulation of the middle

bis(triazolo)benzene core would increase the steric hindrance against floor-

exchanging motions. Such electronic and steric effects should work in the same

direction to raise the activation energy of the processes shown in Figure 11. Indeed,

the activation energy of 3 (15.03 kcal/mol) is the highest among all the triple-decker

molecules reported here (Figure 9).

18



19



20

II.5. Solvent-dependent fluorescence studies

Previous works in our laboratory have shown that the luminescent properties of

bis(triazolo)benzene fluorophores can be controlled by changing the N2-substituents.

The fluorescence emission wavelength of triple-decker bis(triazolo)benzene 1 (λmax,em

= 420 nm) is significantly red-shifted than the reference system 8 (λmax,em = 380 nm),48

indicating the involvement of through-space electron donation from the p-tolyl

pendants. Additionally, the triple-decker system shows a broad emission band with

larger Stokes shift (Δλ = 115 nm) compared with 8 (Δλ = 60 nm).48

Figure 16. Normalized fluorescence emission spectra of 1 (blue line, λexc = 305nm)

and 2 (black line, λexc = 305nm) at 25 ˚C in CHCl3.

A strong CT-character in electronic excitation and de-excitation also

involves through-space interactions. Compound 2 has a dimethylaminophenyl group

to enhance electron donation, which also profoundly impacts the photophysical

21

properties. Compared with 1, a significantly redshifted (Δλ = 196 nm) CT-type

emission was observed for 2 (λmax,em = 516 nm) along with a shorter-wavelength

emission band at λmax,em = 420 nm from tolyl–triazole interaction (Figure 16). To

better understand the nature of the CT-type emission of 2, solvent-dependent

fluorescence measurements were carried out.

Figure 17. Normalized emission spectra of (a) 1, (b) 2 in various solvents: toluene,

ether, THF, EA, CHCl3, CH2Cl2, MeCN, iPrOH, and EtOH at T = 25 ˚C. (c) Plots of

emission energy (cm-1) of 1 and 2 as function of solvent polarity Et(30) parameter. (d)

FMO isosurface plots of the DFT model of 2.

Fluorescence spectra of compounds 1 and 2 were measured in various

solvents (Figure 17a, b). The involvement of charge-separated excited-states was

22

supported by the dependence of emission energy on the solvent polarity. In general, a

red-shift in fluorescence was observed with increasing solvent polarity. Both

compounds 1 and 2 show a linear relationship between the emission energy and

ET(30) values. Such behavior is even more pronounced for compound 2 having

steeper Δνem/ΔET(30) slope (–158; R2 = 0.88) than compound 1 (–60; R2 = 0.88)

(Figure 17c). This finding suggests that aryl pendant with strong electron-donating

group gives rise to stronger CT-character through D–A type through-space interaction.

In support of this notion, a DFT model of compound 2 confirmed that the

highest occupied molecular orbital (HOMO) is localized at the electron-rich aryl

pendant, whereas the lowest unoccupied molecular orbital (LUMO) occupies the

bis(triazolo)benzene and the annexed naphthalene region (Figure 17d). Such spatial

localization of the frontier molecular orbitals (FMOs) should better support CT-type

excited-states.

23

II.6. Variable-temperature fluorescence studies in

polar solvents

VT fluorescence studies were carried out to investigate the functional relevance of

structural folding (through π–π stacking) to photophysical properties. Fluorescence

spectra were obtained from 5 ˚C to 55 ˚C with 5 ˚C intervals; experimental results are

summarized in Figures 18 and 20. In general, fluorescence emission quantum yield

decreases with increasing temperature, since thermally activated bond

twisting/rotating motions serve as non-radiative decay channels for photo-excited

states. This trend was observed all the compounds that we studied (Figure 18), and in

fact, less interesting. More interesting, however, was solvent-dependent changes in

this thermal behavior.

Figure 18. Plots of temperature-dependent changes in ΦT / Φmax ratio in CHCl3.

24

When solvent polarity increased, polyaromatic molecules fold into compact

sturctures form that minimize solvent-exposed surface area.57-59 In the case of the

triple-decker 1, such structural preference would favor the fully-stacked conformers a

and e (Figure 5, Figure 11), in which rotational freedom is significantly restricted for

the C–C/C–N bonds that connect individual aromatic fragments. If the thermal

relaxation channel is effectively blocked through structural folding, an increase in the

fluorescence quantum yield at given temperature is expected in the polar solvent.

Indeed, this is what we observe experimentally (Figure 20.)

Figure 19. Selected examples of self-folding/organizing molecules that minimize

solvent-exposed surface area in polar solvents. 57-58

25

Figure 20. Plots of vs temperature, Here, “nonpolar” denotes CHCl3-

only solvent system; “polar” denotes CHCl3–EtOH (1:1, v/v) mixed-

solvent

Our mechanistic model of folding–unfolding–refolding (proposed in Figure

11) is fully supported by the plots of Φpolar/Φnonpolar (Φpolar = fluorescence quantum

yield (Φ) in polar solvent; Φnonpolar = Φ in nonpolar solvent) obtained for the

compound 1, 3, 8, and 9 as a function of temperature (Figure 19). For the

bis(triazolo)benzenes that cannot fold (compound 8) or can readily stack–destack

(compound 9), the Φpolar/Φnonpolar parameter remains essentially invariant (~ 1) across

the temperature range T = 5 ˚C to 55 ˚C. For triple-decker compounds 1 and 3,

however, the Φpolar/Φnonpolar value is > 1, and increases systematically with increasing

temperature. Most notably, a significantly larger slope (> 12-times)

slope(Φpolar/Φnonpolar vs T) was obtained for compound 3, compared with compound 1

as shown in Figure 20.

This phenomenon reflects a stronger conformational preference toward the

26

fully-stacked triple-decker conformer, which is enforced by the expanded ring

structure of the "middle floor" that imposes a higher steric barrier for internal bond-

rotations and provides larger π-surface avoiding exposure to polar solvent

environment. Both effects work in the same direction, and seem to become more

pronounced at higher temperatures. Alternatively, changes in the solvent exposed

surface between the folded and unfolded conformation would be most dramatic for 3,

so that fluorescence quenching by collision with solvent would have the largest

impact. The sharp increase in relative fluorescent quantum yield in the polar solvent

with increasing temperature is consistent with this interpretation as well.

27

Figure 21. VT-fluorescence studies of (a) 8 (λexc = 310 nm, λem,max = 365 nm), (b) 9

(λexc = 315 nm, λem,max = 420 nm), (c) 1 (λexc = 310 nm, λem,max = 420 nm) and (d) 3

(λexc = 310 nm, λem,max = 450 nm) in CHCl3.

28

Figure 22. VT-fluorescence study of (a) 8 (λexc = 305 nm, λem,max = 365 nm), (b) 9

(λexc = 305 nm, λem,max = 420 nm), (c) 1 (λexc = 315 nm, λem,max = 420 nm) and (d) 3

(λexc = 305 nm, λem,max = 450 nm) in CHCl3–EtOH (1 : 1, v/v) mixed solvent.

29

III. Conclusion

In this work, I have prepared a series of new triple-decker molecules that

spontaneously fold into intimate intramolecular π-stacks. As a structural mimic of

biological "turn" motif, 1,8-disubstituted naphthalene was employed to bring parallel-

stacked aromatics into close proximity. In solution, these molecules undergo floor-

exchanging motions through mechanically-coupled bond-rotating motions. The

underlying molecular mechanism of this process was probed in detail by a

combination of variable-temperature (VT) spectroscopic and X-ray crystallographic

studies. Comparative studies on a series triple-decker molecules and their lower-

dimension analogues revealed key steric and electronic factors that dictate both the

conformational stability and through-space interactions of vertically aligned π-stacks.

Ideally, future works need to be directed toward “multi-floor” π-stacks with

“programmed” sequences, which take full advantage of the key findings obtained in

the proof-of-concept systems described here.

30

IV. Experimental Section

General Considerations. All reagents were obtained from commercial suppliers and

used as received unless otherwise noted. For solvent-dependent fluorescence

measurement, HPLC-grade toluene, dichloromethane, ether, EtOAc, THF, MeCN,

EtOH, and iPrOH were used. The compounds 2,7-bis(4-(tert-butyl)phenyl)-2,7-

dihydrobenzo[1,2-d:3,4-d']bis([1,2,3]triazole) (compound 8),48 N-(naphthalen-1-

yl)picolinamide,44 4-iodo-N,N-dimethylaniline,60 1-butyl-4-iodobenzene,61 N-(8-(4-

Bromophenyl)naphthalen-1-yl)picolinamide,43 8-p-tolylnaphthalen-1-amine,44 and

1,2,4,5-tetrazine62 were prepared according to literature procedures.

Physical Measurements. 1H NMR and 13C NMR spectra were recorded on a 300

MHz Bruker Advance DPX-300, a 400 MHz JeolJNM-LA400 with LFG, or a 500

MHz Varian/Oxford As-500 NMR Spectrometer. Chemical shifts were reported

versus tetramethylsilane and referenced to the residual solvent peaks. FT-IR spectra

were recorded on a SHIMADZU IRTracer-100 FT- IR Spectrophotometer. High-

resolution electrospray ionization (ESI) mass spectra were obtained on an ESI-Q-TOF

mass spectrometer (Compact, Bruker Daltonics Inc) at the Organic Chemistry

Research Center at Sogang University. Fluorescence spectra were recorded on a

Photon Technology International Quanta-Master 400 spectrouorometer with FelixGX

software. Quantum yields were determined by using an integrating sphere installed on

the instrument.

Computational Studies. Geometry optimizations and geometry scans were

31

performed with the B3LYP functional and the 6-31G(d) basis set. The entire

calculations were performed with Gaussian '09 Revision E.01 software.69

32

Chemical Numbering Scheme and Summary of Synthetic Routes

33

N-(8-(4-(Dimethylamino)phenyl)naphthalen-1-yl)picolinamide (2a).

A mixture of N-(naphthalen-1-yl)picolinamide (1.12 g, 4.51 mmol), 4-iodo-N,N-

dimethylaniline (1.90 g, 7.70 mmol), Pd(OAc)2 (138 mg, 0.615 mmol), and KOAc

(1.37 g, 14.0 mmol) in xylene (40 mL) was stirred at reflux for 14 h. After the reaction

was complete, the mixture was cooled to r.t., diluted with EtOAc (150 mL), filtered

through Celite, and concentrated under reduced pressure. Flash column

chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:4, v/v) furnished 2a as a brown

oil (665 mg, 1.81 mmol, yield = 40%). 1H NMR (500 MHz, CDCl3, 298 K): δ 9.87 (br

s, 1H), 8.34 (dd, J = 7.6, 1.2 Hz, 1H), 8.15–8.11 (m, 2H), 7.84 (dd, J = 8.2, 1.2 Hz,

1H), 7.80–7.74 (m, 2H), 7.57 (t, J = 7.9 Hz, 1H), 7.47 (dd, J = 8.1, 7.1 Hz, 1H), 7.34

(dd, J = 7.0, 1.4 Hz, 1H), 7.28 (ddd, J = 6.6, 4.7, 3.3 Hz, 3H), 6.55–6.52 (m, 2H), 2.79

(s, 6H). 13C NMR (125 MHz, CDCl3, 298 K): δ 162.02, 150.39, 149.66, 147.52,

138.09, 136.86, 135.68, 133.37, 130.54, 130.47, 130.10, 128.08, 126.17, 125.81,

125.49, 125.08, 125.02, 121.94, 121.73, 112.14, 40.40. FT-IR (ATR, cm-1): 1676,

1608, 1523, 1492, 1429, 1348, 1290, 1227, 1198, 1124, 997, 945, 905, 814, 768.

HRMS (ESI) calcd for C26H20N3ONa [M + Na]+ 390.1577, found 390.1577.

N-(8-(4-Butylphenyl)naphthalen-1-yl)picolinamide (6a).

A mixture of N-(naphthalen-1-yl)picolinamide (1.17 g, 4.71 mmol), 1-butyl-4-

iodobenzene (4.58 g, 17.6 mmol), Pd(OAc)2 (326 mg, 1.45 mmol), and KOAc (1.08 g,

11.0 mmol) in xylene (30 mL) was stirred at reflux for 150 h. After the reaction was

complete, the mixture was cooled to r.t., diluted with EtOAc (100 mL), filtered


34

chromatography on SiO2 (hexane:EtOAc = 100:1 to 4:1, v/v) furnished 6a as a brown

oil (887 mg, 2.33 mmol, yield = 50%). 1H NMR (500 MHz, CDCl3, 298 K): δ 9.61 (s,

1H), 8.24 (d, J = 7.5 Hz, 1H), 8.18 (d, J = 4.7 Hz, 1H), 8.10 (d, J = 7.8 Hz, 1H), 7.87

(d, J = 8.2 Hz, 1H), 7.77 (ddd, J = 10.0, 9.4, 4.9 Hz, 2H), 7.57 (t, J = 7.8 Hz, 1H),

7.51–7.45 (m, 1H), 7.32 (dt, J = 12.8, 5.9 Hz, 4H), 6.99 (d, J = 7.9 Hz, 2H), 2.37–2.31

(m, 2H), 1.37–1.34 (m, 2H), 1.25 (m, 3H), 0.89 (t, J = 7.3 Hz, 3H). 13C NMR (125

MHz, CDCl3, 298 K): δ 161.80, 149.89, 147.36, 141.54, 139.87, 137.73, 136.88,

135.48, 132.94, 130.46, 129.01, 128.42, 127.94, 126.26, 125.84, 125.65, 125.02,

124.93, 122.26, 121.81, 77.24, 76.99, 76.73, 35.23, 33.39, 22.49, 13.98. FT-IR (ATR,

cm-1): 3304, 3057, 2959, 2928, 2953, 1738, 1686, 1570, 1526, 1495, 1463, 1431, 1373,

1332, 1236, 1126, 1086, 1040, 999, 883, 820, 768, 746. HRMS (ESI) calcd for

C26H24N2ONa [M + Na]+ 403.1781, found 403.1781.

8-(4-(Dimethylamino)phenyl)naphthalen-1-amine (2b).

A mixture of 2a (690 mg, 1.88 mmol) and NaOH (520 mg, 13.0 mmol) in EtOH (20

mL) was stirred at reflux for 19 h. After the reaction was complete, the mixture was

diluted with EtOAc (200 mL), filtered through Celite, and concentrated under reduced

pressure. Flash column chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:2, v/v)

furnished 2b as a red oil (230 mg), which was carried on to the next step due to

oxidative instability.

8-(4-Butylphenyl)naphthalen-1-amine (6b).

A mixture of 6a (887 mg, 2.33 mmol) and NaOH (697 mg, 22.2 mmol) in EtOH (23

mL) was stirred at reflux for 14 h. After the reaction was complete, the mixture was

35

diluted with EtOAc (170 mL), filtered through Celite, and concentrated under reduced


furnished 6b as a red oil (297 mg), which was carried on to the next step due to

oxidative instability.

8-(4-Bromophenyl)naphthalen-1-amine (7b).

A mixture of 8-(4-bromophenyl)naphthalen-1-amine (5.88 g, 14.6 mmol) and NaOH

(3.40 g, 85.0 mmol) in EtOH (100 mL) was stirred at reflux for 42 h. After the

reaction was complete, the mixture was diluted with EtOAc (500 mL), filtered


chromatography on SiO2 (hexane:EtOAc = 100:1 to 2:1, v/v) furnished 7b as a red oil

(2.70 g), which was carried on to the next step due to oxidative instability.

4-((8-(p-Tolyl)naphthalen-1-yl)diazenyl)-1,3-benzenediamine (1c).

To a stirred MeOH (10 mL) solution of 8-p-tolylnaphthalen-1-amine (1.40 g, 6.00

mmol) at 0 °C was added slowly conc. H2SO4 (0.6 mL) over a period of 5 min. An

aqueous solution (3 mL) of NaNO2 (801 mg, 11.6 mmol) was added dropwise for 1

min to generate the diazonium intermediate, and the reaction mixture was stirred for

10 min at 0 °C. A solution of m-phenylenediamine (1.02 g, 9.43 mmol) dissolved in

pyridine (10 mL) was kept at 0 °C. With stirring, the diazonium intermediate was

added dropwise to the m-phenylenediamine solution over a period of 10 min while

maintaining the temperature of the reaction at 0 °C. After stirring for 1 h at r.t., the

mixture was treated with water (200 mL) and extracted into CH2Cl2 (3 × 200 mL).

The combined extracts were dried over anhyd MgSO4, filtered, and concentrated

36

under reduced pressure. Flash column chromatography on SiO2 (hexane:EtOAc =

100:1 to 1:5, v/v) furnished 1c as a red waxy solid (1.84 g, 5.22 mmol, yield = 87%).

1H NMR (500 MHz, CDCl3, 298 K): δ 7.88 (ddd, J = 12.8, 8.2, 1.2 Hz, 2H), 7.55–

7.51 (m, 2H), 7.42 (dd, J = 7.1, 1.3 Hz, 1H), 7.38 (dd, J = 7.4, 1.2 Hz, 1H), 7.15–7.11

(m, 2H), 7.09–7.00 (m, 3H), 5.99 (dd, J = 8.6, 2.3 Hz, 1H), 5.72 (d, J = 2.4 Hz, 1H),

4.97 (br s, 2H), 3.89 (br s, 2H), 2.31 (s, 3H). 13C NMR (125 MHz, CDCl3, 298 K): δ

151.65, 150.31, 142.40, 139.53, 135.85, 135.52, 132.42, 130.17, 129.35, 128.91,

128.32, 128.08, 127.48, 126.19, 125.43, 114.40, 105.75, 99.01, 21.26. FT-IR (ATR,

cm-1): 3454, 3379, 3201, 3026, 1620, 1497, 1371, 1323, 1271, 1240, 1201, 1130, 1024,

905, 829, 816, 771. HRMS (ESI) calcd for C26H20N3ONa [M + Na]+ 390.1577, found

390.1577.

4-((8-(4-Butylphenyl)naphthalen-1-yl)diazenyl)benzene-1,3-diamine (6c).

To a stirred MeOH (6 mL) solution of 6a (297 mg, 1.08 mmol) at 0 °C was added

slowly conc. H2SO4 (0.15 mL) over a period of 1 min. An aqueous solution (1 mL) of

NaNO2 (207 mg, 3.00 mmol) was added dropwise over a period of 1 min to generate

the diazonium intermediate, and the reaction mixture was stirred for 10 min at 0 °C. A

pyridine (3 mL) solution of m-phenylenediamine (160 mg, 1.48 mmol) was kept at

0 °C. With stirring, the diazonium intermediate was added dropwise to the m-

phenylenediamine solution over a period of 5 min, while maintaining the temperature

of the reaction at 0 °C. After stirring for 1 h at r.t., the mixture was treated with water

(50 mL) and extracted into CH2Cl2 (3 × 50 mL). The combined extracts were dried

over anhyd MgSO4, filtered, and concentrated under reduced pressure. Flash column

chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:1, v/v) furnished 6c as a red

37

solid (164 mg, 0.416 mmol, yield = 39%). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.87

(dd, J = 13.8, 8.1 Hz, 2H), 7.55–7.49 (m, 2H), 7.41 (d, J = 7.0 Hz, 1H), 7.36 (d, J =

7.4 Hz, 1H), 7.21 (d, J = 7.7 Hz, 1H), 7.14 (d, J = 8.0 Hz, 2H), 7.02 (d, J = 7.9 Hz,

2H), 6.00 (dd, J = 8.6, 2.2 Hz, 1H), 5.65 (d, J = 2.3 Hz, 1H), 5.02 (s, 2H), 3.87 (s, 2H),

2.56–2.51 (m, 2H), 1.57–1.49 (m, 3H), 1.38 (m, 2H), 0.95 (t, J = 7.3 Hz, 3H). 13C

NMR (125 MHz, CDCl3, 298 K): δ 151.45, 149.94, 144.47, 142.28, 140.98, 139.37,

135.40, 132.23, 130.14, 129.23, 128.68, 127.91, 127.52, 127.22, 126.08, 125.29,

114.33, 105.63, 98.99, 77.26, 77.00, 76.75, 35.49, 34.26, 22.73, 14.17. FT-IR (ATR,

cm-1): 2932, 2924, 2853, 1676, 1620, 1570, 1514, 1464, 1431, 1371, 1329, 1267, 1184,

1084, 997, 959, 885, 822, 768, 733. HRMS (ESI) calcd for C26H27N4 [M + H]+

395.2230, found 395.2231.

4-((8-(4-Bromophenyl)naphthalen-1-yl)diazenyl)benzene-1,3-diamine (7c).

To a stirred solution of 7b (1.098 g, 3.682 mmol) dissolved in MeOH (5 mL) and

water (5 mL) at 0 °C was added conc. H2SO4 (0.5 mL) over a period of 5 min. An

aqueous solution (2 mL) of NaNO2 (445 mg, 6.45 mmol) was added dropwise over a

period of 1 min to generate the diazonium intermediate, and the reaction mixture was

stirred for 10 min at 0 °C. A pyridine (7 mL) solution of m-phenylenediamine (542 mg,

5.01 mmol) was kept at 0 °C. With stirring, the diazonium intermediate was added

dropwise to the m-phenylenediamine solution over a period of 5 min while

maintaining the temperature of the reaction at 0 °C. After stirring for 1 h at r.t., the

mixture was treated with water (200 mL) and extracted into CH2Cl2 (3 × 200 mL).



38

100:1 to 1:1, v/v) furnished 7c as a red waxy solid (721 mg, 1.73 mmol, yield = 47%).

1H NMR (500 MHz, CDCl3, 298 K): δ 7.92 (d, J = 8.2 Hz, 1H), 7.87 (d, J = 8.1 Hz,

1H), 7.57–7.51 (m, 2H), 7.40–7.36 (m, 2H), 7.36–7.32 (m, 2H), 7.13–7.08 (m, 2H),

6.98 (br s, 1H), 6.04 (dd, J = 8.7, 2.3 Hz, 1H), 5.81 (d, J = 2.3 Hz, 1H), 5.03 (s, 2H),

3.95 (s, 2H). 13C NMR (125 MHz, CDCl3, 298 K): δ 151.35, 150.61, 144.33, 138.09,

135.30, 132.24, 130.94, 130.51, 129.91, 128.75, 128.49, 127.11, 126.23, 125.19,

120.13, 114.48, 106.11, 99.01, 90.42, 77.22, 76.97, 76.71. FT-IR (ATR, cm-1):3462,

3379, 3037, 1618, 1485, 1369, 1321, 1269, 1207, 1200, 1124, 1057, 1009, 923, 820,

770, 735. HRMS (ESI) calcd for C22H18BrN4 [M + H]+ 417.0709, found 417.0711.

2-(8-(p-Tolyl)naphthalen-1-yl)-2H-benzo[d][1,2,3]triazol-5-amine (1d).

A MeCN solution (120 mL) of 1c (1.84 g, 5.22 mmol) and Cu(OAc)2·H2O (5.37 g,

26.9 mmol) was heated at reflux for 30 min. Volatile fractions were removed under

reduced pressure. The residual material was treated with an aqueous solution of

Na2EDTA (0.1 M, 400 mL) and extracted into EtOAc (2 × 300 mL). The combined

extracts were dried over anhyd MgSO4, filtered, and concentrated. Flash column

chromatography on SiO2 (EtOAc only) furnished 1d as a brown-black powder (1.56

g). Due to its instability, this material was immediately carried on to the next step.

2,7-Bis(8-(p-tolyl)naphthalen-1-yl)-2,7-dihydrobenzo[1,2-d:3,4-

d']bis([1,2,3]triazole) (1).

39

To a stirred MeOH (3 mL) solution of 8-p-tolylnaphthalen-1-amine (290 mg, 1.24

mmol) at 0 °C was added slowly conc. H2SO4 (0.2 mL) over a period of 1 min. An

aqueous solution (2 mL) of NaNO2 (170 mg, 2.46 mmol) was added dropwise over a

period of 1 min to generate the diazonium intermediate, and the reaction mixture was

stirred for 10 min at 0 °C. A solution of 1d (449 mg, 1.28 mmol) dissolved in pyridine

(3 mL) and THF (3 mL) was kept at 0 °C. With stirring, the diazonium intermediate

was added dropwise to the solution of 1d over a period of 5 min, while maintaining

the temperature of the reaction 0 °C. After stirring for 1 h at r.t., the mixture was

treated with water (100 mL) and extracted into CH2Cl2 (3 × 70 mL). The combined

extracts were dried over anhyd MgSO4, filtered, and concentrated under reduced

pressure to isolate the azo coupling product, which was carried on the subsequent

oxidative cyclization step without further purification.

[NOTE: In a separate small-scale synthesis, the crude product was purified by flash

column chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:5, v/v) to furnish the

azo coupling reaction product as a red solid. 1H NMR (500 MHz, CDCl3, 298 K): δ

8.10 (dd, J = 8.3, 1.2 Hz, 1H), 7.97 (dd, J = 8.3, 1.2 Hz, 1H), 7.93–7.90 (m, 2H), 7.87

(dd, J = 7.3, 1.3 Hz, 1H), 7.70 (dd, J = 7.5, 1.3 Hz, 1H), 7.64–7.59 (m, 3H), 7.57 (d, J

= 7.3 Hz, 1H), 7.56–7.53 (m, 1H), 7.47 (ddd, J = 13.6, 7.1, 1.3 Hz, 2H), 7.35 (d, J =

9.1 Hz, 1H), 7.05 (br, 2H), 6.90 (br, 1H), 6.56 (d, J = 7.3 Hz, 2H), 6.47 (d, J = 9.1 Hz,

1H), 5.88 (br s, 2H), 2.28 (s, 3H), 1.82 (s, 3H). 13C NMR (125 MHz, CDCl3, 298 K): δ

151.49, 145.30, 142.26, 139.66, 139.09, 138.68, 138.68, 138.66, 137.72, 136.29,

135.69, 135.57, 135.14, 131.69, 131.23, 130.51, 129.48, 129.28, 129.19, 128.36,

128.13, 127.19, 127.01, 126.91, 126.47, 126.08, 125.48, 124.78, 122.43, 122.08,

40

121.26, 115.97, 21.20, 20.77. FT-IR (ATR, cm-1): 2986, 2899, 1734, 1697, 1683, 1652,

1616, 1558, 1506, 1456, 1373, 1224, 1056, 813, 767. HRMS (ESI) calcd for

C40H30N6Na [M + Na]+ 617.2424, found 617.2422)]

A MeCN–CH2Cl2 (30 mL, 2;1, v/v) solution of the above material and Cu(OAc)2·H2O

(982 mg, 4.92 mmol) was heated at reflux for 1.5 h. Volatile fractions were removed

under reduced pressure. The residual material was treated with an aqueous solution of




furnished 1 as a red-brown solid (377 mg, 0.636 mmol, combined yield for two steps

= 51%). 1H NMR (500 MHz, CDCl3, 298 K): δ 8.17 (d, J = 7.0 Hz, 2H), 8.00 (d, J =

7.0 Hz, 2H), 7.90 (dd, J = 7.3, 1.3 Hz, 2H), 7.71 (dd, J = 8.2, 7.3 Hz, 2H), 7.60 (dd, J

= 8.2, 7.1 Hz, 2H), 7.47–7.43 (m, 4H), 6.87 (br s, 4H), 6.44 (br s, 4H), 1.56 (s, 6H).

13C NMR (125 MHz, CDCl3, 298 K): δ 144.31, 138.44, 138.35, 137.39, 135.67,

135.57, 135.00, 131.83, 131.59, 128.16, 127.16, 126.81, 126.68, 126.24, 124.77,

117.95, 20.34. FT-IR (ATR, cm-1): 2978, 2964, 2905, 1635, 1558, 1539, 1506, 1456,

1377, 1213, 1196, 1045, 957, 883, 813, 766. HRMS (ESI) calcd for C40H28N6Na [M +

Na]+ 615.2268, found 615.2266.

N,N-Dimethyl-4-(8-(7-(8-(p-tolyl)naphthalen-1-yl)benzo[1,2-d:3,4-

d']bis([1,2,3]triazole)-2(7H)-yl)naphthalen-1-yl)aniline (2).

To a stirred MeOH (2 mL) solution of 2b (50 mg, 0.19 mmol) at 0 °C was added

slowly conc. H2SO4 (0.05 mL) over a period of 1 min. An aqueous solution (1 mL) of

41

NaNO2 (68 mg, 0.99 mmol) was added dropwise over a period of 1 min to generate

the diazonium intermediate, and the reaction mixture was stirred for 10 min at 0 °C. A

solution of 1d (99 mg, 0.28 mmol) in THF–pyridine (2 mL, 1:1, v/v) was kept at 0 °C.

With stirring, the diazonium intermediate was delivered dropwise to the solution of 1d

over a period of 5 min, while maintaining the temperature of the reaction at 0 °C.

After stirring for 1 h at r.t., the mixture was treated with water (30 mL) and extracted

into CH2Cl2 (3 × 30 mL). The combined extracts were dried over anhyd MgSO4,

filtered, and concentrated under reduced pressure to isolate the azo coupling product,

which was carried on to the subsequent oxidative cyclization step without further

purification.

[NOTE: In a separate small-scale synthesis, the crude product was purified by flash

column chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:4, v/v) to furnish the

azo coupling reaction product as a red solid. 1H NMR (500 MHz, CDCl3, 298 K): δ

8.10 (dd, J = 8.2, 1.2 Hz, 1H), 7.97 (dd, J = 8.3, 1.2 Hz, 1H), 7.88 (ddd, J = 16.0, 7.7,

1.2 Hz, 3H), 7.67 (dd, J = 7.4, 1.3 Hz, 1H), 7.64–7.51 (m, 5H), 7.49–7.45 (m, 2H),

7.38 (d, J = 9.0 Hz, 1H), 6.88–6.80 (br, J = 37.5 Hz, 4H), 6.53 (br s, 2H), 6.45 (d, J =

9.1 Hz, 1H), 6.28 (br s, 1H), 5.90 (br s, 2H), 2.81 (s, 6H), 1.77 (s, 3H). 13C NMR (125

MHz, CDCl3, 298 K): δ 151.85, 150.02, 145.28, 139.70, 139.41, 138.70, 138.62,

138.60, 137.77, 135.73, 135.70, 135.21, 133.52, 131.70, 131.25, 130.13, 129.41,

128.12, 127.68, 127.49, 127.16, 126.81, 126.35, 126.09, 125.57, 124.75, 122.26,

122.04, 121.57, 115.53, 41.06, 20.65. FT-IR (ATR, cm-1): 2988, 2945, 2878, 2787,

1734, 1616, 1558, 1520, 1506, 1373, 1228, 1217, 1201, 1068, 1055, 829, 814, 766.

HRMS (ESI) calcd for C41H34N7 [M + H]+ 624.2870, found 624.2868)]

42

A MeCN–CH2Cl2 (22 mL, 10;1, v/v) solution of the above material and

Cu(OAc)2·H2O (212 mg, 1.06 mmol) was heated at reflux for 1 h. Volatile fractions

were removed under reduced pressure. The residual material was treated with an

aqueous solution of Na2EDTA (0.1 M, 40 mL) and extracted into EtOAc (2 × 40 mL).



100:1 to 1:3, v/v) furnished 2 as a pale yellow solid (45 mg, 0.072 mmol, combined

yield for two steps = 13%). 1H NMR (500 MHz, CDCl3, 298 K): δ 8.16 (ddd, J = 8.3,

3.1, 1.2 Hz, 2H), 7.98 (ddd, J = 16.5, 8.2, 1.1 Hz, 2H), 7.87 (dd, J = 7.3, 1.3 Hz, 1H),

7.82 (dd, J = 7.3, 1.3 Hz, 1H), 7.71–7.66 (m, 2H), 7.62–7.57 (m, 2H), 7.48–7.43 (m,

3H), 7.38 (d, J = 9.3 Hz, 1H), 6.82 (br, 4H), 6.42 (br s, 2H), 5.96 (br s, 2H), 2.27 (s,

6H), 1.54 (s, 3H). 13C NMR (125 MHz, CDCl3, 298 K): δ 148.13, 144.38, 138.87,

138.53, 138.43, 137.66, 137.47, 135.87, 135.80, 135.69, 135.13, 131.94, 131.77,

131.62, 131.56, 128.21, 127.59, 126.87, 126.73, 126.64, 126.60, 126.36, 124.78,

124.65, 118.11, 117.74, 40.01, 29.85, 20.39. FT-IR (ATR, cm-1): 3044, 2920, 2851,

2791, 1734, 1611, 1521, 1458, 1433, 1383, 1354, 1221, 1198, 1123, 1092, 957, 885,

829, 814, 768. HRMS (ESI) calcd for C41H32N7 [M + H]+ 622.2714, found 622.2713.

2,7-Bis(8-(4-butylphenyl)naphthalen-1-yl)-2,7-dihydrobenzo[1,2-d:3,4-


A stirred MeCN solution (10 mL) of 6c (82 mg, 0.208 mmol) and Cu(OAc)2·H2O

(197 mg, 0.987 mmol) was heated at reflux for 30 min. Volatile fractions were

removed under reduced pressure. The residual material was treated with an aqueous

43

solution of Na2EDTA (0.5 M, 50 mL) and extracted into EtOAc (2 × 100 mL). The

combined extracts were dried over anhyd MgSO4, filtered, and concentrated under

reduced pressure to isolate the crude mono(triazolo)benzene product, which was

placed under reduced pressure for 2 h, and carried on to the subsequent azo coupling

step without further purification.

To a stirred MeOH (2 mL) solution of 6a (120 mg, 0.436 mmol) at 0 °C was

added slowly conc. H2SO4 (0.03 mL) over a period of 1 min. An aqueous solution (1

mL) of NaNO2 (78 mg, 1.1 mmol) was added dropwise over a period of 1 min to

generate the diazonium intermediate, and the reaction mixture was stirred for 10 min

at 0 °C. A THF–pyridine (2 mL, 1:1, v/v) solution of the crude mono(triazolo)benzene

(see above) was kept at 0 °C. With stirring, the diazonium intermediate was delivered

dropwise over a period of 5 min, while maintaining the temperature of the reaction at

0 °C. After stirring for 1 h at r.t., the mixture was treated with water (50 mL), and

extracted into CH2Cl2 (3 × 50 mL). The combined extracts were dried over anhyd

MgSO4, filtered, and concentrated under reduced pressure to isolate the azo coupling

product, which was carried on the subsequent oxidative cyclization step without

further purification.

A stirred MeCN–CH2Cl2 (6 mL, 1:1, v/v) solution of the above material and



aqueous solution of Na2EDTA (0.5 M, 100 mL) and extracted into EtOAc (2 × 100

mL). The combined extracts were dried over anhyd MgSO4, filtered, and concentrated


100:1 to 2:1, v/v) furnished 6 as a dark brown solid (19 mg, 0.028 mmol, combined

44

yield for three steps = 13%). 1H NMR (500 MHz, CDCl3, 298 K): δ 8.16 (d, J = 8.2

Hz, 1H), 7.99 (d, J = 8.1 Hz, 1H), 7.83 (d, J = 7.2 Hz, 1H), 7.70 (s, 1H), 7.60 (s, 1H),

7.45 (d, J = 7.0 Hz, 1H), 7.40 (s, 1H), 6.90 (m, 2H), 6.46 (br s, 2H), 1.83 (br s, 2H),

1.01 (m, 2H), 0.85–0.76 (m, 2H), 0.73 (t, J = 7.3 Hz, 3H). 13C NMR (125 MHz,

CDCl3, 298 K): δ 144.30, 140.12, 138.46, 137.41, 135.68, 135.50, 131.81, 131.30,

127.88, 126.62, 126.45, 126.37, 126.17, 124.65, 117.92, 77.23, 76.97, 76.72, 34.53,

32.99, 22.26, 13.77. FT-IR (ATR, cm-1): 2953, 2920, 2853, 1726, 1591, 1381, 1263,

1094, 1045, 999, 957, 885, 824, 800, 768, 735 HRMS (ESI) calcd for C46H40N6Na [M

+ Na]+ 699.3207, found 699.3209.

2,7-Bis(8-(4-bromophenyl)naphthalen-1-yl)-2,7-dihydrobenzo[1,2-d:3,4-


A stirred MeCN solution (10 mL) of 7c (208 g, 0.498 mmol) and Cu(OAc)2·H2O (498

mg, 2.49 mmol) was heated at reflux for 30 min. Volatile fractions were removed

under reduced pressure to isolate the crude mono(triazolo)benzene product, which

was placed under reduced pressure for 2 h, and carried on to the subsequent azo

coupling step without further purification.

To a stirred MeOH (1 mL) solution of 7b (176 mg, 0.590 mmol) at 0 °C was

added slowly conc. H2SO4 (0.1 mL) over a period of 1 min. An aqueous solution (1

mL) of NaNO2 (146 mg, 2.12 mmol) was added dropwise over a period of 1 min to


at 0 °C. A THF–pyridine (4 mL, 1:3, v/v) solution of the crude mono(triazolo)benzene

(see above) was kept at 0 °C. With stirring, the diazonium intermediate was added

dropwise over a period of 5 min, while maintaining the temperature of the reaction at

45

0 °C. After stirring for 1 h at r.t., the mixture was treated with an aqueous solution of



pressure to isolate the azo coupling product, which was carried on the subsequent

oxidative cycllization step.

A stirred MeCN–CH2Cl2 (4 mL, 1:1, v/v) solution of the above material and



aqueous solution of Na2EDTA (0.5 M, 50 mL) and extracted into EtOAc (2 × 50 mL).



100:1 to 5:1, v/v) furnished 2 as a brown solid (60 mg, 0.083 mmol, combined yield

for three steps = 17%). 1H NMR (500 MHz, CDCl3, 298 K): δ 8.19 (dd, J = 8.3, 1.0

Hz, 1H), 8.03 (d, J = 8.2 Hz, 1H), 7.94 (dd, J = 7.3, 1.2 Hz, 1H), 7.74 (d, J = 7.5 Hz,

1H), 7.59 (t, J = 4.0 Hz, 2H), 7.40–7.36 (m, 1H), 7.00–6.60 (br m, , 4H). 13C NMR

(125 MHz, CDCl3, 298 K): δ 144.65, 139.93, 137.12, 137.01, 135.45, 135.23, 131.59,

131.53, 128.68, 127.37, 126.55, 126.00, 125.00, 119.46, 118.36, 77.22, 76.97, 76.71.

FT-IR (ATR, cm-1): 3043, 1595, 1508, 1487, 1431, 1382, 1227, 1182, 1126, 1070,

1011, 957, 885, 818, 775, 767, 718 HRMS (ESI) calcd for C38H22N6Br2Na [M + Na]+

743.0165, found 743.0164.

N-(8-(p-Tolyl)naphthalen-1-yl)acetamide (4).

A CH2Cl2 (10 mL) solution of 8-p-tolylnaphthalen-1-amine (681 mg, 2.92 mmol) and

acetic anhydride (0.450 mL, 4.76 mmol) was stirred at r.t. for 3 h. The reaction was

46

quenched by adding sat’d aq solution of NaHCO3 to neutralize the pH. The mixture

was treated with water (100 mL) and extracted into CH2Cl2 (3 × 100 mL). The

combined extracts were dried over anhyd MgSO4, filtered, and concentrated under

reduced pressure. Flash column chromatography on SiO2 (hexane:EtOAc = 100:1 to

1:3, v/v) furnished 4 as a pale yellow solid (710 mg, 2.58 mmol, yield = 88%). 1H

NMR (500 MHz, CDCl3, 298 K): δ 8.07 (dd, J = 7.5, 0.6 Hz, 1H), 7.86 (dd, J = 8.2,

1.2 Hz, 1H), 7.73 (d, J = 7.6 Hz, 1H), 7.49 (t, J = 7.9 Hz, 1H), 7.45 (dd, J = 8.0, 7.2

Hz, 1H), 7.33 (s, 4H), 7.27 (dd, J = 7.0, 1.2 Hz, 1H), 7.13 (br s, 1H), 2.46 (s, 3H), 1.46

(s, 3H). 13C NMR (125 MHz, CDCl3, 298 K): δ 167.87, 140.60, 137.71, 136.86,

135.34, 133.24, 129.87, 129.45, 129.05, 126.05, 125.99, 124.78, 124.14, 121.55,

24.10, 21.30. FT-IR (ATR, cm-1): 3412, 3277, 3047, 3024, 2918, 1683, 1526, 1491,

1429, 1366, 1333, 1290, 1261, 1180, 1109, 1036, 999, 968, 818, 768. HRMS (ESI)

calcd for C19H17NONa [M + Na]+ 298.1202, found 298.1203.

N-(2-(8-(p-Tolyl)naphthalen-1-yl)-2H-benzo[d][1,2,3]triazol-5-yl)acetamide (5).

A CH2Cl2 (2 mL) solution of 1d (80 mg, 0.23 mmol) and acetic anhydride (0.10 mL,

1.0 mmol) was stirred at r.t. for 3 h. The reaction was quenched by adding sat’d aq

solution of NaHCO3 to neutralize the pH. The mixture was treated with water (50 mL)

and extracted into CH2Cl2 (3 × 50 mL). The combined extracts were dried over anhyd

MgSO4, filtered, and concentrated under reduced pressure. Flash column

chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:3, v/v) furnished 5 as a pale

yellow solid (25 mg, 0.064 mmol, yield = 28%). 1H NMR (500 MHz, CDCl3, 298 K):

δ 8.13 (d, J = 8.2 Hz, 1H), 7.99–7.96 (m, 2H), 7.77 (dd, J = 7.3, 1.3 Hz, 1H), 7.65–

7.62 (m, 1H), 7.62–7.58 (m, 1H), 7.55 (d, J = 9.1 Hz, 1H), 7.46 (dd, J = 7.1, 1.2 Hz,

47

1H), 7.24 (br, 2H), 6.85 (d, J = 8.0 Hz, 2H), 6.56 (d, J = 8.0 Hz, 2H), 2.25 (s, 3H),

1.83 (s, 3H).13C NMR (125 MHz, CDCl3, 298 K): δ 168.44, 144.69, 141.89, 138.43,

138.14, 137.58, 135.88, 135.70, 135.41, 131.93, 131.63, 128.15, 127.37, 127.21,

126.77, 126.52, 126.31, 124.81, 121.68, 118.67, 106.77, 24.84, 20.68. FT-IR (ATR,

cm-1): 3286, 3101, 3046, 3008, 2916, 2849, 1666, 1628, 1578, 1545, 1501, 1470, 1449,

1402, 1375, 1319, 1271, 1248, 1005, 962, 897, 822, 814, 768. HRMS (ESI) calcd for

C25H20N4ONa [M + Na]+ 415.1529, found 415.1530.

2,5-Bis(8-(p-tolyl)naphthalen-1-yl)-2,5-dihydrobis([1,2,3]triazolo)[4,5-f:4',5'-

h]phthalazine (3). A sealable 20-mL pressure vessel was loaded with 1 (17 mg, 0.029

mmol) and 1,2,4,5-tetrazine (26 mg, 0.32 mmol) in toluene (3 mL), and heated at

130 °C for 50 h. The reaction mixture was cooled to r.t., diluted with CH2Cl2 (20 mL),

filtered, and concentrated under reduced pressure. Flash column chromatography on

SiO2 (hexane:EtOAc = 100:1 to 1:1, v/v) furnished 3 as a pale yellow solid (7.7 mg,

0.012 mmol, yield = 42%). 1H NMR (500 MHz, CDCl3, 298 K): δ 9.93 (s, 2H), 8.24

(d, J = 8.3 Hz, 2H), 8.06 (d, J = 8.3 Hz, 2H), 8.00 (dd, J = 7.3, 1.0 Hz, 2H), 7.79–7.72

(m, 2H), 7.66 (dd, J = 8.0, 7.3 Hz, 2H), 7.49 (dd, J = 7.0, 1.0 Hz, 2H), 7.04 (br s, 2H),

6.68 (br s, 2H), 6.34–6.24 (br, J = 45.2 Hz, 4H), 1.58 (s, 3H). 13C NMR (75 MHz,

CDCl3, 298 K) δ 146.52, 138.80, 138.06, 137.52, 136.84, 135.81, 135.17, 132.37,

128.57, 127.77, 127.65, 127.41, 127.09, 126.62, 126.34, 124.93, 119.33, 29.85. FT-IR

(ATR, cm-1): 2953, 2920, 2851, 1734, 1684, 1653, 1609, 1543, 1522, 1497, 1456,

1429, 1395, 1373, 1248, 1074, 1065, 1043, 953, 831, 818, 768. HRMS (ESI) calcd for

C40H28N6Na [M + Na]+ 615.2268, found 615.2266.

48

2-(4-(tert-Butyl)phenyl)-7-(8-(p-tolyl)naphthalen-1-yl)-2,7-dihydrobenzo[1,2-

d:3,4-d']bis([1,2,3]triazole) (9).

To a stirred EtOH (1 mL) solution of 4-tert-butylaniline (0.10 mL, 0.67 mmol) at 0 °C

was added slowly conc. H2SO4 (0.1 mL) over a period of 1 min. An aqueous solution

(1 mL) of NaNO2 (67 mg, 0.97 mmol) was added dropwise over a period of 1 min to


at 0 °C. A THF–pyridine (2 mL, 1:1, v/v) solution of 1d (101 mg, 0.288 mmol) was

kept at 0 °C. With stirring, the diazonium intermediate was delivered dropwise to the

solution of 1d over a period of 5 min, while maintaining the temperature of the

reaction at 0 °C. After stirring for 1 h at r.t., the mixture was treated with water (30

mL) and extracted into CH2Cl2 (3 × 30 mL). The combined extracts were dried over

anhyd MgSO4, filtered, and concentrated under reduced pressure to isolate the azo

coupling product, which was carried on to the subsequent oxidative cyclization step

without further purification.

A stirred MeCN (20 mL) solution of the above material (90 mg, 0.18 mmol)

and Cu(OAc)2·H2O (100 mg, 0.501 mmol) was heated at reflux for 1 h. Volatile

fractions were removed under reduced pressure. The residual material was treated

with an aqueous solution of Na2EDTA (0.1 M, 40 mL) and extracted into EtOAc (2 ×

40 mL). The combined extracts were dried over anhydrous MgSO4, filtered, and

concentrated. Flash column chromatography on SiO2 (hexane:EtOAc = 100:1 to 1:1,

v/v) furnished 9 as a pale yellow solid (50 mg, 0.098 mmol, combined yield for two

steps = 15%). 1H NMR (500 MHz, CDCl3, 298 K): δ 8.33 (d, J = 8.6 Hz, 2H), 8.16 (d,

J = 8.2 Hz, 1H), 8.00 (d, J = 8.2 Hz, 1H), 7.85 (d, J = 7.2 Hz, 1H), 7.70 (dd, J = 9.4,

0.4 Hz, 1H), 7.67 (t, J = 7.7 Hz, 1H), 7.63–7.58 (m, 3H), 7.52–7.46 (m, 2H), 6.90 (br

49

s, 2H), 6.58 (br s, 1H), 6.37 (br s, 1H), 1.58 (s, 3H), 1.41 (s, 9H). 13C NMR (125 MHz,

CDCl3, 298 K): δ 152.02, 144.65, 138.38, 138.02, 137.34, 136.13, 135.89, 135.73,

135.32, 131.95, 131.69, 128.24, 127.69, 127.33, 126.97, 126.76, 126.53, 126.32,

124.85, 119.75, 118.97, 117.92, 34.98, 31.48, 20.42. FT-IR (ATR, cm-1): 3049, 2959,

1869, 1844, 1828, 1791, 1772, 1748, 1734, 1716, 1699, 1684, 1668, 1653, 1636, 1616,

1576, 1558, 1539, 1516, 1506, 1472, 1458, 1429, 1418, 1387, 1362, 1269, 1182, 1115,

1070, 959, 837, 814, 802, 768. HRMS (ESI) calcd for C33H28N6Na [M + Na]+

531.2268, found 531.2266.

X-ray Crystallographic Studies on 1. Single crystals of 1 were prepared by slow

diffusion of pentane into a dichloromethane solution of this material. A clear orange

crystal (approximate dimensions 0.731 × 0.576 × 0.395 mm3) was placed onto a nylon

loop with Paratone-N oil, and mounted on a XtaLAB AFC12 (RINC): Kappa dual

home/near diffractometer. Data collection was carried out using Cu Kα radiation and

the crystal was kept at T = 93 K. A total of 10668 reflections were measured (9.14° ≤

2θ ≤ 158.748°). The structure was solved with SHELXT63 using direct methods, and

refined with SHELXL64 refinement package of OLEX2.65 A total of 3179 unique

reflections were used in all calculations. The final R1 was 0.0481 (I ≥ 2σ(I)) and wR2

was 0.1289 (all data).

52


diffusion of pentane into a dichloromethane solution of this material. A clear reddish

crystal (approximate dimensions 0.173 × 0.141 × 0.063 mm3) was placed onto a nylon

loop with Paratone-N oil, and mounted on a SuperNova, Dual, Cu at zero, AtlasS2

diffractometer. Data collection was carried out using Cu Kα radiation and the crystal

was kept at T = 99.97(16) K. A total of 32665 reflections were measured (7.7° ≤ 2θ ≤

153.448°). The structure was solved with SHELXT63 using direct methods, and

refined with SHELXL64 refinement package of OLEX2.65 A total of 13231 unique

reflections were used in all calculations. The final R1 was 0.0397 (I ≥ 2σ(I)) and wR2

was 0.1058 (all data).

55


evaporation of a pentane into a dichloromethane solution of this material. A clear

reddish crystal (approximate dimensions 0.143 × 0.113 × 0.082 mm3) was placed onto

a nylon loop with Paratone-N oil, and mounted on a SuperNova, Dual, Cu at zero,

AtlasS2 diffractometer. Data collection was carried out using Cu Kα radiation and the

crystal was kept at T = 294.30(10) K. A total of 9333 reflections were measured

(8.276° ≤ 2θ ≤ 153.176°). The structure was solved with SHELXT63 using direct

methods, and refined with SHELXL64 refinement package of OLEX2. 65 A total of

3099 unique reflections were used in all calculations. The final R1 was 0.0298 (I ≥

2σ(I)) and wR2 was 0.0823 (all data).

58

References

1. Watson, J. D.; Crick, F. H. C., Nature 1953, 171, 737–738.

2. Hunter, C. A.; Sanders, J. K. M., J. Am. Chem. Soc. 1990, 112, 5525–5534.

3. Liu, L.; Ousaka, N.; Horie, M.; Mamiya, F.; Yashima, E., Chem. Commun. 2016, 52,

11752–11755.

4. Ikai, T.; Awata, S.; Shinohara, K.-i., Polym. chem. 2018, 9, 1541–1546.

5. Nelson, J. C.; Saven, J. G.; Moore, J. S.; Wolynes, P. G., Science 1997, 277, 1793–

1796.

6. Batra, A.; Kladnik, G.; Vázquez, H.; Meisner, J. S.; Floreano, L.; Nuckolls, C.;

Cvetko, D.; Morgante, A.; Venkataraman, L., Nat. Commun. 2012, 3, 1086–1092.

7. Sinnokrot, M. O.; Valeev, E. F.; Sherrill, C. D., J. Am. Chem. Soc. 2002, 124,

10887–10893.

8. Lee, S.; Hua, Y.; Flood, A. H., J. Org. Chem. 2014, 79, 8383–8396.

9. Fimmel, B.; Son, M.; Sung, Y. M.; Grüne, M.; Engels, B.; Kim, D.; Würthner, F.,

Chem. Eur. J. 2015, 21, 615–630.

10. Cappelli, A.; Galeazzi, S.; Giuliani, G.; Anzini, M.; Aggravi, M.; Donati, A.; Zetta,

L.; Boccia, A. C.; Mendichi, R.; Giorgi, G., Macromolecules 2008, 41, 2324–

2334.

11. He, B.; Luo, W.; Hu, S.; Chen, B.; Zhen, S.; Nie, H.; Zhao, Z.; Tang, B. Z., J.

Mater. Chem. C 2017, 5, 12553–12560.

12. Nakano, T., Polym. J. 2010, 42, 103–123.

13. Benniston, A. C.; Harriman, A.; Howell, S. L.; Sams, C. A.; Zhi, Y. G., Chem. Eur.

J. 2007, 13, 4665–4674.

59

14. Cozzi, F.; Annunziata, R.; Benaglia, M.; Baldridge, K. K.; Aguirre, G.; Estrada, J.;

Sritana-Anant, Y.; Siegel, J. S., Phys. Chem. Chem. Phys. 2008, 10, 2686–2694.

15. Lunazzi, L.; Mancinelli, M.; Mazzanti, A., J. Org. Chem. 2008, 73, 2198–2205.

16. Iordache, A.; Oltean, M.; Milet, A.; Thomas, F.; Baptiste, B.; Saint-Aman, E.;

Bucher, C., J. Am. Chem. Soc. 2012, 134, 2653–2671.

17. Muraoka, T.; Kinbara, K.; Aida, T., Nature 2006, 440, 512–515.

18. Takai, A.; Yasuda, T.; Ishizuka, T.; Kojima, T.; Takeuchi, M., Angew. Chem., Int.

Ed. 2013, 52, 9167–9171.

19. Lunazzi, L.; Mancinelli, M.; Mazzanti, A., J. Org. Chem. 2008, 73, 5354–5359.

20. Han, J. J.; Shaller, A. D.; Wang, W.; Li, A. D. Q., J. Am. Chem. Soc. 2008, 130,

6974–6982.

21. Chou, T.-C.; Huang, J.-K.; Bahekar, S. S.; Liao, J.-H., Tetrahedron 2014, 70,

8361–8373.

22. Lewis, F. D.; Delos Santos, G. B.; Liu, W., J. Org. Chem. 2005, 70, 2974–2979.

23. Carini, M.; Ruiz, M. P.; Usabiaga, I.; Fernández, J. A.; Cocinero, E. J.; Melle-

Franco, M.; Diez-Perez, I.; Mateo-Alonso, A., Nat. Commun. 2017, 8, 15195–

15204.

24. Kudo, M.; López, D. C.; Maurizot, V.; Masu, H.; Tanatani, A.; Huc, I., Eur. J. Org.

Chem. 2016, 2016, 2457–2466.

25. Bao, C.; Gan, Q.; Kauffmann, B.; Jiang, H.; Huc, I., Chem. Eur. J. 2009, 15,

11530–11536.

26. Sebaoun, L.; Kauffmann, B.; Delclos, T.; Maurizot, V.; Huc, I., Org. Lett. 2014, 16,

2326–2329.

60

27. Lamouroux, A.; Sebaoun, L.; Wicher, B.; Kauffmann, B.; Ferrand, Y.; Maurizot,

V.; Huc, I., J. Am. Chem. Soc. 2017, 139, 14668–14675.

28. De, S.; Chi, B.; Granier, T.; Qi, T.; Maurizot, V.; Huc, I., Nat. Chem. 2017, 10, 51–

58.

29. Das, A.; Ghosh, S., Angew. Chem., Int. Ed. 2014, 53, 2038–2054; .

30. Nguyen, J. Q.; Iverson, B. L., J. Am. Chem. Soc. 1999, 121, 2639–2640.

31. Scott Lokey, R.; Iverson, B. L., Nature 1995, 375, 303–305.

32. Burattini, S.; Colquhoun, H. M.; Fox, J. D.; Friedmann, D.; Greenland, B. W.;

Harris, P. J. F.; Hayes, W.; Mackay, M. E.; Rowan, S. J., Chem. Commun. 2009,

6717–6719.

33. Cockroft, S. L.; Hunter, C. A.; Lawson, K. R.; Perkins, J.; Urch, C. J., J. Am.

Chem. Soc. 2005, 127, 8594–8595.

34. Skomski, D.; Jo, J.; Tempas, C. D.; Kim, S.; Lee, D.; Tait, S. L., Langmuir 2014,

30, 10050–10056.

35. Yamauchi, Y.; Yoshizawa, M.; Fujita, M., J. Am. Chem. Soc. 2008, 130, 5832–

5833.

36. Zhu, Z.; Bruns, C. J.; Li, H.; Lei, J.; Ke, C.; Liu, Z.; Shafaie, S.; Colquhoun, H.

M.; Stoddart, J. F., Chem. Sci. 2013, 4, 1470–1483.

37. Sugimoto, T.; Sada, K.; Sakamoto, S.; Yamaguchi, K.; Shinkai, S., Chem.

Commun. 2004, 1226–1227.

38. Clough, R. L.; Kung, W. J.; Marsh, R. E.; Roberts, J. D., J. Org. Chem. 1976, 41,

3603–3609.

39. Hirose, T.; Tsunoi, Y.; Fujimori, Y.; Matsuda, K., Chem. Eur. J. 2015, 21, 1637–

1644.

61

40. Kang, Y. K.; Rubtsov, I. V.; Iovine, P. M.; Chen, J.; Therien, M. J., J. Am. Chem.

Soc. 2002, 124, 8275–8279.

41. Kang, Y. K.; Iovine, P. M.; Therien, M. J., Coord. Chem. Rev. 2011, 255, 804–824.

42. Schmidt, H. C.; Spulber, M.; Neuburger, M.; Palivan, C. G.; Meuwly, M.; Wenger,

O. S., J. Org. Chem. 2016, 81, 595–602.

43. Huang, L.; Li, Q.; Wang, C.; Qi, C., J. Org. Chem. 2013, 78, 3030–3038.

44. Zhang, D.; Nadres, E. T.; Brookhart, M.; Daugulis, O., Organometallics 2013, 32,

5136–5143.

45. Shi, Y.; Mai, C.-K.; Fronk, S. L.; Chen, Y.; Bazan, G. C., Macromolecules 2016,

49, 6343–6349.

46. Jo, J.; Lee, H. Y.; Liu, W.; Olasz, A.; Chen, C.-H.; Lee, D., J. Am. Chem. Soc. 2012,

134, 16000–16007.

47. Kim, S.; Jo, J.; Lee, D., Org. Lett. 2016, 18, 4530–4533.

48. Park, B. G.; Hong, D. H.; Lee, H. Y.; Lee, M.; Lee, D., Chem. Eur. J. 2016, 22,

6610–6616.

49. Kim, S.; Castillo, H. D.; Lee, M.; Mortensen, R. D.; Tait, S. L.; Lee, D., J. Am.

Chem. Soc. 2018, 140, 4726–4735.

50. Kang, T.; Kim, H.; Lee, D., Org. Lett. 2017, 19, 6380–6383.

51. Elmer, S. P.; Park, S.; Pande, V. S., J. Chem. Phys. 2005, 123, 114903.

52. Nguyen, H. H.; McAliley, J. H.; Batson, W. R.; Bruce, D. A., Macromolecules

2010, 43, 5932–5942.

53. de Loera, D.; Liu, F.; Houk, K. N.; Garcia-Garibay, M. A., J. Org. Chem. 2013, 78,

11623–11626.

62

54. Friebolin. H. Basic One-and Two-Demensional NMR Spectroscopy, 4th ed.;

Wiley: Chichester, UK, 2004.

55. Brown, W. H.; Iverson, B. L.; Anslyn, E.; Foote, C. S. Organic Chemistry, 8th ed.;

Cengage Learning: Belmont, CA, 2018.

56. Rahanyan, N.; Linden, A.; Baldridge, K. K.; Siegel, J. S., Org. Biomol. Chem.

2009, 7, 2082–2092.

57. Keisuke, J.; Akira, S.; Munetaka, A.; Ken, A.; Kimihisa, Y.; Michito, Y., Angew.

Chem., Int. Ed. 2017, 56, 3570–3574.

58. Kei, K.; Akira, S.; Munetaka, A.; Michito, Y., Angew. Chem., Int. Ed. 2013, 52,

2308–2312.

59. Nengfang, S.; Damien, M.; Laura, G.; Xiaoyong, L.; Vladimir, S.; Volker, B.;

Lyle, I., Chem. Eur. J. 2016, 22, 15270–15279.

60. Thomas, K.; Fatih, A.; Gerd‐Volker, R.; J., G. L., Chem. Eur. J. 2011, 17, 2689–

2697.

61. Feng, X.; Li, L.; Yu, X.; Yamamoto, Y.; Bao, M., Catalysis Today 2016, 274,

129–132.

62. Jürgen, S.; K., H. D.; Josef, H.; Josef, K.; Heinz, S.; Johann, S., Eur. J. Org. Chem.

1998, 12, 2885–2896.

63. Sheldrick, G. M. Acta Cryst. 2015, A71, 3–8.

64. Sheldrick, G. M. Acta Cryst. 2015, C71, 3–8.

65. Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H.

J. Appl. Cryst. 2009, 42, 339–341.

66. Schmidt, M. P.; Hagenböcker, A., Chem. Ber. 1921, 54, 2191–2200.

67. a) Geigy A.G. J.R., UK 603267, 1948; b) Geigy A.G. J. R.,US 2462405, 1949.

63

68. Wuming, Y.; Qiaoyi, W.; Quan, L.; Minyong, L.; L., P. J.; Xiaodong, S., Chem.

Eur. J. 2011, 17, 5011–5018.

69. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.;

Cheeseman, J. R.; Scalmani, G.; Boarone, V.; Mennucci, B.; Petersson, G. A. et

al. Gaussian '09 , revision E.01; Gaussian, Inc.: Wallingford CT, 2009.

64

NMR Spectra

65

1H NMR (500 MHz) and 13C NMR (500 MHz) spectra of 1 in CDCl3 (T = 298 K).

66

2D COSY (T = 233 K, 400MHz) and 2D NOESY (T = 298 K, 400MHz) spectra of 1 in

CDCl3.

67

1H NMR (500 MHz) and 13C NMR (500 MHz) spectra of 1c in CDCl3 (T = 298 K).

68


69

1H NMR (500 MHz) and 13C NMR (500 MHz) spectra of 2a in CDCl3 (T = 298 K).

70


71


72


73


74

1H NMR (500 MHz) and 13C NMR (500 MHz) spectra of 6a in CDCl3 (T = 298 K).

75


76


77


78


79



기계적으로 상호 연관된

분자 운동을 하는 비스트리아졸벤젠

국문 초록

이번 연구에서는 구조적으로 잘 정의된 “트리플-데커”로 불리는 합성

시스템을 연구하였다. 이는 간결한 3 차원의 구조를 지닌 생체 시스템의

모방 및 이해를 위해 디자인되었다. 이 시스템의 구조적 특징은 (i)

회전가능한 결합의 개수를 최소화 하기 위해 1,8-위치가 치환된 나프탈렌

모티프를 회전 모티프로 지니며 (ii) 비스트리아졸로벤젠과 아릴 펜던트를

이용하여 분자 내 전자 주개-받개 형식의 π–π 스태킹을 최대화 한다. 1D

와 2D (COSY 와 NOESY) NMR 과 X-ray 단결정 구조분석을 이용하여

강한 비공유 상호작용이 방향족 고리끼리의 평행한 배열로 강제된다는

것을 알 수 있었다. 다양한 온도에서의 동적 NMR 실험을 통해 더블- 및

트리플-데커의 분자운동의 기계적 상호작용이 전자적, 구조적 요소를 통한

층간 뒤섞임 과정으로 인해 조절됨을 알 수 있었다. 또한 트리플-데커

분자의 형광성이 아릴 펜던트에 의해 영향을 받으며, 이 성질은 공간을

통한 전하-이동 과정으로 설명되었다. 또한 π–π 스태킹을 통한 구조적

접힘은 온도와 용매의 극성에 의해 변화하며, 스택 접힘과 비스택 펼침

구조변환으로 분자의 형광성 변화가 관측된다. 이러한 기계적 모델의

80

구조적, 역학적, 광학적 성질에 관한 연구를 통해 분자내 접힘과정을

지니는 합성분자의 이해를 할 수 있다.

핵심어: 입체구조 전환 • 비스트리아졸로벤젠 • 생체모방분자 • 전하 이동

• 형광 • 핵자기공명법

학번: 2015-22608

disclaimer - seoul national...

Documents