學生 : 王趙增指導老師 : 于淑君博士 2009 / 07 / 20 department of chemistry &...

1

Molecular and Gold Nanoparticles Supported N-Heterocyclic Carbene Silver(I) Complexes – Synthesis, Characterization

and Catalytic Applications

學生 :王趙增指導老師 : 于淑君博士

2009 / 07 / 20Department of Chemistry & Biochemistry

Chung Cheng University

2

N-Heterocyclic Carbenes (NHC)N-Heterocyclic Carbenes (NHC)

NHCs are strongerσ-donors than the most electron rich phosphine- less likely to dissociate from the metal during the reaction

NHCs have come to replace phosphines in many organometallic and organic reactions

NHCs can be useful spectator ligands, tunable electronically and sterically

NHCs are most frequently prepared via deprotonation of the corresponding azolium salts

L-type two electrons

3

N-Heterocyclic Carbenes as LigandsN-Heterocyclic Carbenes as Ligands- In the early 90's NHC were found to have bonding properties similar to trialklyphosphanes( -PR3 ) and alkylphosphinates( -OP(OR)R2 ).

- compatible with both high and low oxidation state metals

- examples:

- reaction employing NHC's as ligands:

Herrmann, W. Angew. Chem. Int. Ed. 2002, 41, 1290-1309.

Herrmann, W. A.; Öfele, K; Elison, M.; Kühn, F. E.; Roesky, P. W. J. Organomet. Chem. 1994, 480, C7-C9.

4

The Applications of Ag(I) NHCThe Applications of Ag(I) NHC Silver(I)-carbene complexes as carbene transfer agentsSilver(I)-carbene complexes as carbene transfer agents

Addition of arenes to imines

Aza-Diels-Alder reaction

Asymmetric aldol reactionAsymmetric aldol reaction

Barbier-Grignard-type reactionBarbier-Grignard-type reaction

MeO

MeO

OMe + ArCH=NTsAuCl3/AgOTf

CH2Cl2

MeO

MeO

OMe

Ar

NHTs

H

O+ CNCH2SO2Tol-p

1 mol%, AgOTf

CH2Cl2 NO

SO2Tol-p

NPh

Ph

+

Me3SiO

OMe

N

O

Ph

Ph10 mol%, AgOTf

THF

H

ONH2+ + I

In/AgI/ZnCl2

RT, H2O

HN

5

The First Silver(I)-Carbene Complexes and The First Silver(I)-Carbene Complexes and Carbene-Copper(I) Complexes

Arduengo A.J. et al. Organometallics 1993, 21, 3405-3409

Linear di-coordination

N

NH

KOtBu

thf

N

N

N

N N

NM+

CF3SO3-

M = Cu, Ag

M+-O3SCF3

thf

Cl

6

Silver(I)-Carbene Complexes as Carbene Silver(I)-Carbene Complexes as Carbene Transfer AgentsTransfer Agents

Wang, H. M. J. ; Lin, I. J. B. Organometallics 1998, 17, 972-975

7The trend of the bond energies for the metal fragments is AuCl > CuCl > AgCl

Boehme, C. and Frenking, G. Organometallics 1998, 17, 5801-5809

Quantum Chemical Calculations for the N-Heterocyclic Carbene Complexes

of MCl (M = Cu, Ag, Au)

8

MotivationMotivation

Using NHCs ligand to replace phosphine ligand in Using NHCs ligand to replace phosphine ligand in organomatallic catalysis.organomatallic catalysis.

In comparison with other transition metals (Cu, Au), silver has been virtually untouched as a catalyst for coupling reactions.

To promote silver-catalyzed three-component coupling of aldehyde, alkyne, and amine.

Easy recovered effectivetly recycledEasy recovered effectivetly recycled Immobilization of NHC-Ag(I) complexs onto Au Nanoparticles.Immobilization of NHC-Ag(I) complexs onto Au Nanoparticles.

9

ExperimentalExperimentalPreparation of [Ag(hmim)Preparation of [Ag(hmim)22]PF]PF66 Complex Complex

N N

N N

65 oC, 12h95 % yield

[Hmim]Br

Br N N

Br

[Hmim]PF6

PF6KPF6

DI 40oC/1h75 % yield

Ag2O, t-BuOK CH2Cl2 r.t / 4 h

75% Ag

NN

N N

PF6Ag

NN

N N

PF6

syn- anti-

10

Space linker synthesis

ExperimentalExperimentalPreparation of Au NPs-Ag(I)(NHC)Preparation of Au NPs-Ag(I)(NHC)22(PF(PF66))

N N +Br

BrDMF / 80oC

12 hNN

Br

Br

1. CS(NH2)2 / ethanol

2. reflux , 16 hr

3. NaOH / 5 min

4. HCl /20 min

NNSH

Br

KPF6NN

SH

PF6

+ DI/40oC

1 h

80%

75% 70%

11

NN SHSS

PF6Au

SN

S

S

S

N

N

N

N

N

N

N

PF6

PF6

PF6

PF6

Au

SS

S

N

N

N

N

N

NPF6

Au

SNN

S

S

PF6

AuAg

Ag

THF

Ag2O, t-BuOK

CH3CN

SSS S S

S

SS

SS

S

S

S

S

ExperimentalExperimentalPreparation of Au NPs-Ag(I)(NHC)Preparation of Au NPs-Ag(I)(NHC)22(PF(PF66))

12

11H NMR Spectra of [Hmim]HPFH NMR Spectra of [Hmim]HPF6 6 andand

[Ag(hmim)[Ag(hmim)22]PF]PF66

2H

13

c

N N

HC

PF6

C

*DMSO

*DMSO

C

C

NN

N N

PF6Ag

C

1313C NMR Spectra of [Hmim]HPFC NMR Spectra of [Hmim]HPF6 6 and and

[Ag(hmim)[Ag(hmim)22]PF]PF66

14

ESI-MS Spectrum of [Ag(hmim)ESI-MS Spectrum of [Ag(hmim)22]PF]PF66

Experimental MS Data

Ag

NN

N N

Calculated MS Data

15

IR Spectra of [Hmim]HPFIR Spectra of [Hmim]HPF66 and [Ag(hmim) and [Ag(hmim)22]PF]PF66

[Ag(hmim)2]PF6 a

(hmim)HPF6 b

4000 3500 3000 2500 2000 1500 1000 500

wavenumber (cm-1)

1225 cm-1

1168 cm-1

NHC H-C-C & H-C-N bending

16

200 300 400 500 600 700 8000.0

0.5

1.0

1.5

2.0

2.5

3.0ab

s.

wavelength (cm-1)

UV Spectra of [Hmim]HPFUV Spectra of [Hmim]HPF6 6 and and

[Ag(hmim)[Ag(hmim)22]] PFPF6 6

[Ag(hmim)2]PF6 a

(hmim)2PF6 b

b

a

π π* 210 nm

17

Single-Crystal X-ray Structure of Single-Crystal X-ray Structure of [Ag(hmim)[Ag(hmim)22]PF]PF66

bond lengths [Å] bond angles [deg]

Ag(1)-C(1) 2.083(3) C(2)-Ag(1)-C(11) 177.16

Ag(1)-C(11) 2.083(3) N(1)- C(1)-N(2) 104.06

N(3)- C(11)-N(4) 104.67

Dihedral Angle1.802o(221)

π π interaction

18

31P NMR19F NMR

11H, H, 3131P, and P, and 1919F Spextra of Au-NPs-NHC F Spextra of Au-NPs-NHC LigandLigand

*DMSO

*

NNSH

PF6

S N

PF6

AuN

-SH

-CH2SH

19

S N N

H H

Ag

S

NN

PF6

HH

SNN

HH

Ag

S N N

PF6

H H

Au

Au

Au

Synthesis of Au NPs-Ag(I)-(NHC) ComplexSynthesis of Au NPs-Ag(I)-(NHC) Complex

Cross-link network structure

PF6

S N N

H H

Ag

NN

HH

SAu

SN

S

S

S

N

N

N

N

N

N

N

S S

SS PF6

PF6

PF6

PF6

Au

Ag2O& t-BuOK

CH3CN r.t./ 4h

20

1 H 2 H

31P NMR 19F NMR

11H, H, 3131P, and P, and 1919F ofF of Au NPs-Ag(I)-NHC ComplexAu NPs-Ag(I)-NHC Complex

PF6

S N N

H H

Ag

NN

HH

SAu

*DMSO

*

S N

PF6

AuN

H

HH

21

11H NMR Spectra of Ligand, Molcular and Au H NMR Spectra of Ligand, Molcular and Au NanoparticlesNanoparticles

*DMSO

*

*

*

22

Particle size 2.1 ± 1.12 nm

Synthesis of Octanethiol Protected Au-SR NPs

SS

AuS

SS S S

SHAuCl44H2OCH3(CH2)7SH /CHCl3

NaBH4 / H2OCHCl3

CH3(CH2)7]4N+Br-

23

Particle size 3.1 ± 1.3 nm

TEM Image and UV Spectrum of Au NTEM Image and UV Spectrum of Au NPs-Immobilized (NHC) LigandPs-Immobilized (NHC) Ligand

230 nm Ligand centered

π π*

200 300 400 500 600 700 800-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

abs.

wavelength (nm)

SN

S

S

S

N

N

N

N

N

N

N

S S

SS PF6

PF6

PF6

PF6

Au

24

TEM Image and EDS of Au NPs-Ag(I) ComplexTEM Image and EDS of Au NPs-Ag(I) Complex

Particle size: 2.1 ± 0.7 nm

200 300 400 500 600 700 8000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

abs.

wavelength (nm)

SS

S

N

N

N

N

N

NPF6

Au

SNN

S

SPF6

AuAg

Ag

S

S

S

S

245 nm

25

IR Spectra of Ligand & Au Nanoparticles seriesIR Spectra of Ligand & Au Nanoparticles series

4000 3500 3000 2500 2000 1500 1000 500

wavenumber (cm-1)

HS(CH2)

6-NHCPF

6 (7)

Au-SR (8) Au-IL (9) Au-(NHC)

2Ag(I)PF

6 (10)

SH stretching

NHC H-C-C & H-C-N bending

1169 cm-1

1229 cm-1

3000 2500 2000

wavenumber (cm-1)

26

Aldehyde, Amine, and Alkyne-coupling Reactions (A3-Coupling)

Have attracted much attention from organic chemists for the coupling products, propargylamines, which are major skeletons or synthetically versatile building blocks for the preparation of many nitrogen-

containing biologically active compounds

J. Org. Chem. 1995, 60, 1590-1594

N

N

O

MeO

NLi

N

NH

O

MeO

N

27

The First Silver-CatalyzedThree-Component Coupling of Aldehyde,

Alkyne, and Amine

Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003,4473-4475

R1-CHO + n + R21.5-3 mol% AgI

H2O, 100oC, N2

R1= aryl, alkyl n=0,1,2

N

R1R2

n

Entry Catalyst (3 mol%) Time (h) Conversion (%)

1 AgOTf 14 40

2 AgBF4 14 35

3 Ag2O 14 40

4 Ag2SO4 14 42

5 AgNO3 14 40

6 AgF 14 40

7 AgBr 14 55

8 AgCl 14 60

9 AgI 14 75

28

Proposed Mechanism Proposed Mechanism for the Three –Component Couplingfor the Three –Component Coupling

Chao J. L. et. al. Org. Lett., Vol. 5, No. 23, 2003,4473-4475

R2 Ag + HN

H

nRCHO

N

n

R1OH

AgR2 H N

R1

R2

n

C-H activation

29Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL

Entry Solvent, Temperature Time Conversion (%)a

1 Propionitrile (97oC) 1hr 91

2 Acetonitril (83oC) 1hr 73

3 (hmim)Br 1hr 29

4 (hmim)PF6 1hr 78

5 1,4-dioxane (105 oC) 1hr 20

6 DMF (154oC) 1hr 38

Ag(I)-Catalyzed A3-Coupling Reactions

H

O+

NH

+ Cat. 3 (3 mol%)

N2, Solvent, 100oC

N

30

O

HH

O

O

H O

H

O

H

OOMe

H

OMe

H

OCl

H

OCl

H

Aldehyde

Amine NH N

H

O HN

HN N

H

NH

HN

HN

BrSiAlkyne

R3-CHO + NHR2

R1

+ R4

Cat. 3, 1.5 ~3.0 mol%

reflux, PropionitrileN

R3

R4

R1

R2

Ag(I)-Catalyzed A3-Coupling Reactions

31

Reaction conditions: catalyst loading = 1.5 mol%; Benzaldehyde = 1.00 mmol; Piperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol; Propionitrile = 1.0 mL

Entry Time (h) Yielda (%)

1 0.5 93

2 0.5 92

3 0.5 95

4 0.5 95

5 0.5 93

HR

O+ +

Cat.(3) (1.5 mol%)

reflux, PropionitrileNH

N

R

O

H

H

O

O

H

O

H

H H

O

O

R H

A3-Coupling Reactions of Aliphaticaldehyde, Amine, and Alkyne

32

+NH

+ Cat. (3) (3 mol%)

reflux, propionitrile

N

H

O

R

R

Entry R Time (h) Yielda (%)

1 H0.512

919598

2 p-OMe

0.512

2.5

35516585

3 p-Me 2 65

4 p-Cl2

2.57388

5 o-Cl2

2.53

687583

A3-Coupling Reactions of Aromaticaldehyde, Amine, and Alkyne

Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL

33

Entry Time (min) Yielda (%)

1 30 93

2 30 95

3 30 80

4 30 93

A3-Coupling Reactions of para-Formaldehyde, Amine, and Alkyne

NH

R1

R2

HN

HN

NH

O

NH

Cat.(3) (1.5 mol%)

reflux, Propionitrile++ NH

H H

O

R1

R2 NR1

R2


34


Cat.(3) (1.5 mol%)


H H

O

R1

R2 NR1

R2

Entry Time (min) Yielda (%)

5 3060

7590

6 306090

637589

7 3060

8088

8 306090

718994

NH

R1

R2

NH

NH

NH

HN


35

+ +Cat. (3) 1.5 mol%


NRR

H

O

Entry R Time (h) Yielda (%)

1 0.5 92

2

0.54

1224

026

10

30.54

12

101518

Si

Br

A3-coupling Reactions of Benzaldehyde, Amine, and Alkyne

pKa

19.9

26.5

24

Reaction conditions: catalyst loading = 3 mol%; Benzaldehyde = 1.00 mmol; Pyperidine = 1.20 mmol; Phenylacetylene = 1.50 mmol solvent = 1.0 mL

36

Convection transition

Thermal v.s. Microwave Heating

Kappe, C. O. Angew. Chem. Int. Ed. 2004, 43, 6250-6284.

microwave thermal

37


Entry Time (sec) Yielda (%)

1 40 89

2 40 95

3 30 85

4 40 92

HR

O+ +

Cat.(3) (1.5 mol%)


N

R

O

H

H

O

O

HO

H

O

R H

A3-Coupling Reactions of Aliphaticaldehyde, Amine, and Alkyne

38


1 20 89

2 20 92

3 40 90

4 20 93

A3-coupling Reactions of para-Formaldehyde, Amine, and Alkyne

NH

R1

R2

HN

HN

NH

O

NH

Cat.(3) (1.5 mol%)


H H

O

R1

R2 NR1

R2


39


Cat.(3) (1.5 mol%)


H H

O

R1

R2 NR1

R2


5 30 90

640 85

7 20

80

830 83

NH

R1

R2

NH

NH

NH

HN


40


1 60 89

2 60 83

3 60 78

A3-Coupling Reactions of Benzaldehyde, Amine, and Alkyne

NH

R1

R2

HN

HN

NH

O


H

O+ +

Cat. (3) 3 mol%0.5 mL (Hmim)PF6

Microwave, 600 wNH

R1

R2

NR1

R2

41

Proposed Mechanism for the A3-Coupling Reaction

NH H

ONH

OHOH

N

CCAg

N

N N

PF6

N

+ Ag

N

N N

PF6

N

H

C CH

N+

Ag

N

N N

PF6

N

H2O

HO

H

-H2O

HO

OHH

-H2O, OH N

enamine ion

Cat.3

Cat.3

N NN N

enamine ion resonance form

42

A3-Coupling Reactions Catalyzed by a Reusable PS-supported Ag(I)-NHC complex

Wang, Li. P.; Zhang, Y. L.; Wang M. Tetrahedron Letters 49 2008 6650–6654

1.Structure indefinite

2.Quantitative NHC-Silver (I)

by ICP-Mass

24 h

43

Au-[hmim]2AgPF6: 9 mg

1,2,4,5-tetramethylbenzene: 5 mg

d6-DMSO

4 H

2 H

1,2,4,5-tetramethylbenzene

0.25 : 0.13 = X : 0.03725X = 0. 07164 mmol – lignad0.07164×0.5 = 0.0358 mmol- metal center0.0358/9 = 0.004 mol/g

PF6

S N N

H H

Ag

NN

HH

SAu

Quantitative by NMR

AA analysis: 0.0038 mol/g ICP-Mass anlysis: 0.0039 mol/g

需時 2 天

送校外

10 min

44Reaction conditions: Catalyst loading = 20 mol%; para-formaldehyde = 1.00 mmol; pyperidine = 1.10 mmol; phenylacetylene = 1.50 mmol propionitrile = 1.0 mL

NH

+neat

+H H

O H2C N

Cat. (10)

Recycle No.

Time (h) Yield (%)

1 2 93

2 2 97

3 2 96

4 2 95

5 2 93

6 2 94

7 2 92

8 2 93

9 2 91

10 2 90

11 2 90

12 2 91

Reusable Au NPs-Ag(I)(NHC)2PF6

Catalyst for A3-Coupling Reaction

45

Reactivity Comparision Between Au NPs-Ag(I)(NHC)(PF6) and [Ag(hmim)2]PF6

HR

O+ +

Cat. (3) & Cat. (10)1.5 mol%

Propionitrile, reflux 97oCNH

N

R

EntryTime(min)

Cat. 3Yield (%)

Cat. 10Yield (%)

110 2030

65 83 95

83 92 > 99

210 20 30

52 78 93

44 67 88

310 20 30

68 81 93

61 77 91

410 20 30

69 82 92

58 74 93

O

H

H

O

O

H

O

H

O

R H


46

ConclusionsConclusions1.The air- and water-stable catalyst [Ag(hmim)2]PF6 was synthesize

d and characterized by 1H- and 13C-NMR, ESI-MS, IR, UV, X-ray.

2.We have developed a methodology to successfully immobilize [Ag(hmim)2]PF6 onto surfaces of Au NPs. The structure of the sup

ported Ag(I)-NHC complex catalyst was characterized by 1H-NMR, IR, TEM, UV, EDS, AA, ICP-Mass.

3.Since the Au NPs- Ag(I) hybrid catalysts are highly soluble in organic solvents, their structures and reactions were studied by si

mple solution NMR technique.

4. We have successfully demonstrated the catalytic activity of the Ag(I) complex for the three-component coupling reactions of a

ldehyde, alkyne, and amine.

5. The Au NPs- Ag(I) catalyst can be quantitatively recovered and effectively reused for many times without any loss of reactivity.

學生 : 王趙增 指導老師 : 于淑君 博士 2009 / 07 / 20 department of chemistry &...

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學生 : 王趙增指導老師 : 于淑君博士 2009 / 07 / 20 department of chemistry &...