Coordination compoundsCoordination compoundsCoordination compoundsCoordination compounds

มหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสนมหาวทยาลยเกษตรศาสตร กาแพงแสน

1

Reference� J.E. Huheey, E.A. Keiter, and R.L. Keiter, Inorganic Chemistry; Principles of structure and Reactivity.

� F. A. Cotton and G. Wilkinson, Advanced Inorganic � F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry.

� D.F. Shriver, P.W. Atkins, and C. H. Langford. , Inorganic Chemistry.

� B.E. Douglas, D.H. McDaniel, and J.J. Alexander, Concepts and models of inorganic Chemistry.

2

Bonding in Coordination Compounds

• Valence Bond Theory (VBT)• Crystal Field Theory (CFT)

3

Valence Bond Theory (VBT)

'()*+'+,-./01/23 1930 89: Linus Pauling ;<=/>?@?1AB1/ACDE 1950-1960

1ABI<JKK?L hybridization L=IDC?E d-orbitals KJO orbitals 1/8<I=;KC/K<?E1/ coordination compounds RJ/S='+,-KT9U=-2V/RJ/S=8W009T-/'8W-D-</XY

Metal ion + Ligand Coor. cpds.Metal ion + Ligand Coor. cpds.

Lewis acids

(metals or metal ions)

Lewis bases(ligands)

(e- pair acceptor) (e- pair donor)

Coordinate covalent bond

KL9--O.Lewis salt or adduct

4

Co [Ar]3d74s2

Co3+ [Ar]3d6 ,ground state, 5D

Ex.

5

'>?\@]^E-KT9K?L Hybridization ?

� ������� E ����� ��� ������������� overlap �� E !�� NH3� �%&�'�� hybrid orbital �� ��� �������./���0��� NH3 ���1'� pure orbital ���1'� pure orbital

6

Valence Bond Theory� Metal or metal ion: Lewis acid

� Ligand: Lewis base

� Hybridization of s, p, d orbitals

C.N. Geometry HybridsC.N. Geometry

4 tetrahedral

56

4

Hybrids

sp3

square planar dsp2

trigonal bipyramidal dsp3 or sp3doctahedral d2sp3 or sp3d2<--(4d)(3d)-->

7

Cr(CO)6 Cr = [Ar] 3d5 4s1

Fe(CO)5 Fe = [Ar] 3d6 4s2

Ni(CO)4 Ni = [Ar] 3d8 4s2

CO = 0

Diamagnetic

Cr = [Ar] 3d5 4s1

3d5 4s1 4p0

Cr* = [Ar]

Cr(CO)6 = [Ar]

d2sp3 hybrid Octahedral

3d6 4s0 4p0

8

Fe(CO)5 Fe = [Ar] 3d6 4s2

CO = 0

Fe = [Ar] 3d6 4s2

3d6 4s2 4p0

3d8 4s0 4p0

Fe* = [Ar]

Fe(CO)5 = [Ar]

dsp3 hybrid Trigonal bipyramid

9

Ni(CO)4 Ni = [Ar] 3d8 4s2

CO = 0

Ni = [Ar] 3d8 4s2

3d8 4s2 4p0

3d10 4s0 4p0

Ni* = [Ar]

Ni(CO)4 = [Ar]

sp3 hybrid Tetrahedral

10

[Cr(H2O)6]3+ Cr = [Ar] 3d5 4s1

Cr = [Ar] 3d5 4s1

3d8 4s2 4p0

Cr3+ = [Ar] 3d33d3 4s0 4p0

[Cr(H2O)6]3+ = [Ar]

d2sp3 hybrid Octahedral

Innerparamagnetic

Cr3+ = [Ar] 3d3

11

[Ni(H2O)6]2+ Ni = [Ar] 3d8 4s2

Ni = [Ar] 3d8 4s2

3d8 4s2 4p0

Ni2+ = [Ar] 3d83d8 4s0 4p0

4d0

4d0

[Ni(H2O)6]3+ = [Ar]

sp3d2 hybrid Octahedral

Outerparamagnetic

Ni2+ = [Ar] 3d8

12

Co3+ [Ar]3d6

CoF63-

sp3d2 hybrid orbitals

electrons from F-, octahedral

3d 4s 4p

4d

Outer complex

Co3+ [Ar]3d6

CoF63-

d2sp3 hybrid orbitals

electrons from F-, octahedral

3d 4s 4p

Inner complex13

Outer ILo0 Inner ?� '>?K?L'9<0E

�Diamagnetic or paramagneticMagnetic Property

1845, Michael Faraday

paramagnetic, diamagnetic

Magnetic susceptibility Gouy

Faraday

14

� 1AB'()*+0STO?:q<K?L'9<0E

� Inner complex or outer complex

� [Cr(H2O)6]3+ - - - - - > q<K?L'9<0E-2V/ paramagnetic

d2sp3 hybrid orbitals; inner complex

3d orbital @+ E t,>?KDC? 4d orbital RJ/S=L=IDC?E 0T00/u0E M-L 89: inner d U=;uvE;LEKDC? outer d

� [Ni(H2O)6]2+ - - - - - > q<K?L'9<0E-2V/ paramagnetic� [Ni(H2O)6]2+ - - - - - > q<K?L'9<0E-2V/ paramagnetic

sp3d2 hybrid orbitals; outer complex

3d orbital \@CDC?E ]^E;@B e- -9+,:D 2 e-U=UJOWwC ;tCKv'>?1IB 3d orbital DC?E

;WC orbital -9+:D-'C?/Jx/ X^,E\@C-R+:ER0 U^EtB0E1AB 4d orbital

� [CoF6]3- - - - - - > q<K?L'9<0E-2V/ paramagnetic

sp3 d2hybrid orbitals; Outer complex

15

� K?LUJ98WLE.LB?Eu0E [CoF6]3- 'JxE.0E;OO Wo0 inner ;<= outer complex U=-KT9\9BKJO M '+,@+ U./. e- 1/ d orbital -2V/ 4, 5 ILo0 6 U=-2V/;OO19tB0ERTU?Ly?

�Hybrid orbital '+,1AB e- 1/ 3 d @+ E < 4d; 3d U^E-KT9RJ/S=KJO ligand \9B;uvE;LEKDC? 4d ∴∴∴∴K?L-KT9 inner complex U^E@+80K?.@?KKDC? outer complex

]B?@+ e- -9+,:D0:wC1/ 3d orbital K?L'+,U=/>? e- @?-uB?WwCKJ/tB0E1AB E .CD/I/^,E�]B?@+ e- -9+,:D0:wC1/ 3d orbital K?L'+,U=/>? e- @?-uB?WwCKJ/tB0E1AB E .CD/I/^,E

�]B?1AB 4d 1/K?L hybrid 1/K?L-KT9 hybridization @J/\@CtB0E-.+: E '+,U=OJEWJO1IB e- @?-uB?WwCKJ/ ∴∴∴∴ K?L-KT9 outer complex U^E@+80K?.@?KKDC? inner complex

�1st series d4, d6 U=-KT9 inner complex KJO ligand tC?E { :K-DB/ ligand '+,-2V/ H2O, F- U=\9B outer complex

16

Metal '+,-KT9RJ/S=KJO ligand tJD19Kvt?@U=@+.@OJtT-2V/ paramagnetic /J,/Wo0 Fe3+

3d5

Fe = [Ar] 3d6 4s2

Fe3+ ;OO 1 = [Ar] 3d5

Fe3+ ;OO 2 = [Ar] 3d5

4s 4p 4d

Fe3+ ;OO 1 = [Ar] 3d5 6 Ligand -KT9 sp3d2 ; outer complex @+ 5 unpair e-

Fe3+ ;OO 2 = [Ar] 3d5 6 Ligand -KT9 d2sp3 ; inner complex @+ 1 unpair e-

17

Pt2+ [Xe]4f145d8

PtCl42-

dsp2 hybrid orbitals

electrons from Cl-, square planar

5d8 6s0 6p

electrons from Cl-, square planar

Ni2+ [Ar]3d8

NiCl42-

sp3 hybrid orbitals

electrons from Cl-, tetrahedral

3d8 4s0 4p

18

U|90C0/u0E'()*+ Valence bond

� VBT �� �1� CN = 4 �0. ��9/9 ':�'��������1�� ;������� :��� �<.: '���=�

� 9 '�� ��>�0. �������./���� cpx. ;/��B��� 1st transition cpx. FG��� 9 '�� ��>�0. �������./���� cpx. ;/��B��� 1 transition cpx. FG���&H� cpx. ��� ���

� 9 '�� ��>�0. �����/%/����:�� UV-Vis ����K�����./ d-d transition �� cpx.

� 9 '�� ��>�0. �������./ inner ���� outer complex 9/

19

Crystal Field Theory (CFT)

20

Crystal Field Theory (CFT)

1929, Hans Bethe

1935, modifications J.H. Vanvleck

MO + CF

Ligand Field Theory (LFT)

1950, apply CFT to transition metal complexes

successful in interpreting many important properties of complexes

21

Crystal Field Theory (CFT)

� ;KB\u VBT O?E0:C?E\@C.?@?L]0STO?:\9B�.?L2L=K0O CN = 4 (8WLE.LB?E'+,\@C;/C/0/)

�.@OJtT;@C-I<vK�.@OJtT;@C-I<vK

�K?L-KT9.+

� RTU?Ly?;LEKL='>?L=IDC?E metal ion + ligand -2V/;LEKL='>?\}}~?.]Tt (electrostatic force) 2L=U|/TD-W<+:.u0E metal 9^E9w9 ligand (e-

u0E ligand) X,E ligand '>?I/B?'+,-2V/U|92L=U|\}}~? (point charge)

22

-Ro,0U=-uB?1U0T'STR<u0E./?@\}}~?U?K2L=U|<Ou0E L '+,@+tC0 d orbitals 'JxE 5 u0E M U>?-2V/tB0E-uB?1ULw2LC?E 'T�'?EK?LUJ9tJD ;<=K?LKL=U?:u0E e- 1/ d orbitals

dz - y , dz - x2 2 2 2

egt2g

23

24

Octahedral Complexes

� 0T'STR<./?@\}}~?U?K L (ligand field srength)

�4s @+L=9JO E .wEu^x/ ---------nondegenerate

�4p @+L=9JO E .wEu^x/ ;tC 3 orbitals '+,@+L=9JO E -'C?KJ/---------triply degenerate

�3d @+L=9JO E .wEu^x/ ;<=U?KK?L'+,@+ lobe A+xt?@;/D;K/ ;<=L=IDC?E;K/'>?1IB�3d @+L=9JO E .wEu^x/ ;<=U?KK?L'+,@+ lobe A+xt?@;/D;K/ ;<=L=IDC?E;K/'>?1IB-KT9K?L;:Ku0EL=9JO E

25

d-Orbitals and Ligand Interaction(Octahedral Field)

�Ligands approach metald-orbitals pointing directly at axis are affected most by electrostatic interaction

d-orbitals not pointing directly at axis are least affected (stabilized) by electrostatic interaction

most by electrostatic interaction

26

Octahedral Complexes

27

Splitting of the d orbitals by an octahedral field

t2g

eg

3/5∆∆∆∆o

2/5∆∆∆∆o

10Dq

+0.6 ∆∆∆∆O

-0.4 ∆∆∆∆OCenter of gravity, barycenter

eg ---> e = 2 orbitals '+@+ E -'C?KJ/ (doubly degenerate

∆∆∆∆O

eg ---> e = 2 orbitals '+@+ E -'C?KJ/ (doubly degenerate g = gerade K?LUJ9tJD'+,@+�w/:YK<?E.@@?tL (-WLo,0EI@?:}�EKYAJ/W<o,/-I@o0/KJ/

'+,L=:='?E'JxE.0E9B?/ (tLEKJ/uB?@) IC?EU?KU|9�w/:YK<?E-'C?KJ/ u = ungerade -WLo,0EI@?:}�EKYAJ/W<o,/tLEKJ/uB?@ 1/L=:=IC?EU?KU|9�w/:YK<?E-'C?KJ/

t2g---> t = 3 orbitals '+@+ E -'C?KJ/ (triply degenerate)∆∆∆∆O = crystal field splitting energy10Dq (D and q = 2LT@?y'+,\9BU?K.@K?L'?EWyTt�?.tLYu0E;OOU>?<0E\}}~?.]Tt:Y (electrostatic

model) 10 -2V/.J@2L=.T'ST�'+,\9BU?KK?LW>?/Dy)28

f-orbitals f ,f , f

f ,f , f

f

x3 y3 z3

x(y2-z2) y(x2-z2) z(x2-y2)

xyz

f ,f , ff ,f , f

f ,f , f

f

x3 y3 z3

x(y2-z2) y(x2-z2) z(x2-y2)

xyz29

Splitting of the d-orbitals by an octahedral field

t2g

eg

3/5∆∆∆∆o

2/5∆∆∆∆o

10Dqbarycenter

0.0

0.5

1.0

log εεεε

Frequency

20,300 cm-1

[Ti(H2O)6]3+ d1

t2g1eg

0 t2geg1

Purple

243 kJ/mol (∆∆∆∆o)

30

Tetrahedral

dxzdxy dyzt2

M

dx2-y2 dz2

∆∆∆∆t

e

barycenter

31

Splitting energy of Tetrahedral complexs

� ∆∆∆∆ t < ∆∆∆∆ O /J,/Wo0 ∆∆∆∆ t ≈≈≈≈ 4/9 ∆∆∆∆ O

.?L2L=K0O cubic complexes

e

t2

2/5∆∆∆∆t

3/5∆∆∆∆t

∆∆∆∆t = 4/9 ∆∆∆∆o(high spin)

cube� .?L2L=K0O cubic complexes

� K?L split u0E d-orbitals U=-I@o0/KJO tetrahedral complexes

� Splitting energy U=-2V/ 2 -'C?1/ tetrahedral complexes

� 8 ligands <B0@L0O M ion = 2 ∆∆∆∆ t

cube

32

Square Planar Crystal Field

Q -@o,0 L ;/D;K/ z :o9:?D00K > L 1/;/D;K/ x, y '>?1IBRJ/S='JxE 6 :?D\@C-'C?KJ/ (-.+:R<JEE?/RJ/S=) '>?1IB8WLE.LB?EOT9-O+x:DU?K octahedral -2V/ tetragonol -/o,0EU?Kq<KL='O Jahn-Teller Effect

QZ I<|900KU?K metal U=\9B square planar

Q -@o,0 L ;/D;K/ z :o9:?D00K > L 1/;/D;K/ x, y '>?1IBRJ/S='JxE 6 :?D\@C-'C?KJ/ (-.+:R<JEE?/RJ/S=) '>?1IB8WLE.LB?EOT9-O+x:DU?K octahedral -2V/ tetragonol -/o,0EU?Kq<KL='O Jahn-Teller Effect

QZ I<|900KU?K metal U=\9B square planar

33

Splitting of the d orbitals in a square planar field (d8)

eg

z2

x2- y2

x2- y2

xyb2g

b1g

∆∆∆∆O

t2g

xz, yz

xy

z2

xz, yzeg

a1g

Removal of z ligands

Ni(CN)42-

, PdCl42-

,

Pt(NH3)42+

, PtCl42-

,

AuCl4-

0.656∆∆∆∆O

0.086∆∆∆∆O

34

Electron Configuration in d-orbitals

∆E ∆E

Unpaired e- �� 2 orbitals ��� ���/� E :����� = ∆E

Model 1; weak field-high spin cpx.

Esystem = E0 + E0 + ∆∆∆∆E

E0 = E u0E e- ;tC<=tJD

∆o < P

Model 2; strong field � low spin cpx.

Esystem = E0 + E0 + P

P = pairing energy

∆o > P

35

��Only the dOnly the d44 through dthrough d77 cases have both highcases have both high--spin and low spin configuration.spin and low spin configuration.

d4 high spinWeak Field

Electron Configuration for Octahedral complexes of metal Electron Configuration for Octahedral complexes of metal ion having dion having d11 to dto d1010 configuration.configuration.

d4 Strong Field

36

Electron Configuration in Octahedral Field

�� Electron configuration of metal ion:Electron configuration of metal ion:

ss--electrons are lost first. electrons are lost first.

TiTi33++ is a dis a d11, V, V33++ is dis d22 , and Cr, and Cr33++ is dis d33

�� Hund's rule:Hund's rule:

First three electrons are in separate d orbitals with First three electrons are in separate d orbitals with their spins parallel.their spins parallel.their spins parallel.their spins parallel.

�� Fourth eFourth e-- has choice:has choice:

Higher orbital if Higher orbital if ∆∆∆∆∆∆∆∆ is small; High spinis small; High spin

Lower orbital if Lower orbital if ∆∆∆∆∆∆∆∆ is large: Low spin.is large: Low spin.�� Weak field ligandsWeak field ligands

Small Small ∆∆∆∆∆∆∆∆ , High spin complex, High spin complex�� Strong field LigandsStrong field Ligands

Large Large ∆∆∆∆∆∆∆∆ , Low spin complex, Low spin complex 37

weak field case strong field case

with paramagnetic with diamagnetic

38

Electron Configuration for tetrahedral complexes of metal ion Electron Configuration for tetrahedral complexes of metal ion having dhaving d11 to dto d1010 configuration.configuration.

e

t2

2/5∆∆∆∆t

3/5∆∆∆∆t

∆∆∆∆t = 4/9 ∆∆∆∆o

dxy, dyz, dzx

dz , dx - y2 2 2dz , dx - y2 2 2

Tetrahedral (Td) lacks a center of inversion 39

Electron Configuration for tetrahedral complexes of metal ion Electron Configuration for tetrahedral complexes of metal ion having dhaving d11 to dto d1010 configuration.configuration.

d3-d6 ---------- 1. high spin; weak field

2. low spin; strong field

2�UUJ:; ∆∆∆∆t ;<= P ∆∆∆∆t ≈ ≈ ≈ ≈ 4////9∆∆∆∆o ; ∆∆∆∆t /B0:

40

tetrahedral complexestetrahedral complexes

Only high spin41

Electron Configuration for square planar complexesElectron Configuration for square planar complexes

d8 = Ni2+, Pd2+, Pt2+, Rh+1, Ir+1

∆ > P 42

Crystal-field Stabilization EnergyR<JEE?/'+,'>?1IB cpx. @+WD?@-.]+:L 0J/-/o,0EU?K./?@\}}~?U?K ligand '+,@+0T'STR<tC0K?L;:Ku0E d-orbital u0E metal ion '+,]wK ligand <B0@L0O89:I?U?K8WLE;OO0T-<vKtL0/1/\90=;KL@R<JEE?/u0E d-orbitals

CFSE = x(-0.4Dq) + y(+0.6Dq)+ PCFSE = x(-0.4Dq) + y(+0.6Dq)+ P

wherex = number of electrons in lower levelsy = number of electrons in upper levels

43

Pairing energy� e- 2 tJDU=0:wC1/ orbital -9+:DKJ/\9BU=tB0E;

� 1. A/=;LEq<JK'+,-KT9U?K e- - e- (Internal repulsion energy)

� 2. R<JEE?/'+,@?A9-A:R<JEE?/'+,-.+:\21/K?LOJEWJO1IB e- @+ spin tLEuB?@ /Jx/Wo0 Exchange energy

� Energy of pairing electrons

� ΠΠΠΠcis the Coulombic energy of repulsion (always positive when pairing) and ΠΠΠΠe

is the quantum mechanical exchange energy (always negative).

ec Π+Π=Π

∆∆∆∆o ∆∆∆∆o

Weak field; ∆∆∆∆o < P (pairing energy)

High spin

Strong field; ∆∆∆∆o > P (pairing energy)

Low spin

c e

mechanical exchange energy (always negative).

� ΠΠΠΠerelates to the number of exchangeable pairs in a particular electron configuration. This term is

negative and depends on the number of possible states.

Determine ΠΠΠΠcand ΠΠΠΠe

for a d 5 metal complex (low and high spin).

44

Crystal Field Stabilization Energy, CFSE

LFSE = -0.4Dq -0.8Dq -1.2Dq

d1 d2 d3

LFSE =

High Spin Low Spin High Spin Low Spin

-0.6Dq -1.6Dq+P 0Dq -2.0Dq+2P

d4 d5

45

Crystal Field Stabilization Energy, CFSE

LFSE =

High Spin Low Spin High Spin Low Spin

-0.4Dq+P -2.4Dq+3P -0.8Dq+2P -1.8Dq+3P

d6 d7

LFSE = -0.4Dq+P -2.4Dq+3P -0.8Dq+2P -1.8Dq+3P

LFSE = -1.2Dq+3P -0.6Dq+4P 0Dq+5P

d8 d9 d10

46

CFSE of Octahedral ComplexesExample Strong Weak

d0 Ca+2,Sc+3 0 up e- 0 Dq 0 upe- 0 Dqd1 Ti+3 1 -0.4 1 -0.4d2 V+3 2 -0.8 2 -0.8d3 Cr+3, V+2 3 -1.2 3 -1.2d4 Cr+2, Mn+3 2 -1.6 4 -0.6d4 Cr+2, Mn+3 2 -1.6 4 -0.6d5 Mn+2, Fe+3 1 -2.0 5 0d6 Fe+2, Co+3 0 -2.4 4 -0.4d7 Co+2 1 -1.8 3 -0.8d8 Ni+2 2 -1.2 2 -1.2d9 Cu+2 1 -0.6 1 -0.6d10 Cu+, Zn+2 0 0 0 0

47

Magnitude of CF Splitting (∆∆∆∆∆∆∆∆ or 10Dq)11. Metal: . Metal:

-- Larger metal larger Larger metal larger ∆∆∆∆∆∆∆∆-- Higher Oxidation State larger Higher Oxidation State larger ∆∆∆∆∆∆∆∆ -/o,0EU?K 2L=U|'+,/TD-W<+:.u0E -/o,0EU?K 2L=U|'+,/TD-W<+:.u0E M ion M ion @?KU=9E9w9 @?KU=9E9w9 L L '+,<B0@L0O1IB-uB?1K<B@?K '>?1IB-KT9K?L '+,<B0@L0O1IB-uB?1K<B@?K '>?1IB-KT9K?L spite spite @?K@?KRu(H2O)62+ ∆∆∆∆o = 19800 cm-1 Ru(H2O)63+ ∆∆∆∆o = 28600 cm-12 6 o

22. . Number and geometry of the ligands-- Octahedral Octahedral 6 6 ligandligand-- Tetrahedral Tetrahedral 4 4 ligandligand

33. . Nature of the metal ion--∆∆∆∆∆∆∆∆OO series series 22 > > ∆∆∆∆∆∆∆∆OO series series 11 ≈≈≈≈≈≈≈≈ 5050%%--∆∆∆∆∆∆∆∆OO series series 33 > > ∆∆∆∆∆∆∆∆OO series series 22 ≈≈≈≈≈≈≈≈ 2525%%∴∴∴∴∴∴∴∴ series series 22, , 3 3 @JK-2V/ @JK-2V/ low spin complex low spin complex -/o,0EU?K -/o,0EU?K ∆∆∆∆∆∆∆∆OO @+WC?@?K@+WC?@?K 48

44. Ligand: Spectrochemical series. Ligand: Spectrochemical seriesI-<Br-<S2-<SCN-<ClCl-- <NO<NO33

--< F< F-- <OH<OH--<ox<ox22--< H< H22O O < NCS< NCS-- <CH<CH33CN<NHCN<NH33

< en <bipy<phen< NO< en <bipy<phen< NO22-- < (N< (N--bonded)<phosph < CNbonded)<phosph < CN--<CO<CO

Weak field Ligand: Weak field Ligand: Low electrostatic interaction: small CF splitting.Low electrostatic interaction: small CF splitting.High field LigandHigh field Ligand: High electrostatic interaction: large CF splitting.: High electrostatic interaction: large CF splitting.

Spectrochemical series: Increasing Spectrochemical series: Increasing ∆∆∆∆∆∆∆∆ 49

Spectrochemical seriesSpectrochemical seriesI-<Br-<S2-<SCN-<ClCl-- <NO<NO33

--< F< F-- <OH<OH--<ox<ox22--< H< H22O O < NCS< NCS-- <CH<CH33CN<NHCN<NH33

< en <bipy<phen< NO< en <bipy<phen< NO22-- < (N< (N--bonded)<phosph < CNbonded)<phosph < CN--<CO<CO 50

Example� Using the Spectrochemical Series to Predict Magnetic Properties.

� How many unpaired electrons would you expect to find in the octahedral complex [Fe(CN)6666]]]]3333----????

51

CFSE of octahedral complexes

-2/5(5e- )∆∆∆∆ + 2P52

e CFSE e CFSE

d1 t2g1 1 0.4 ∆∆∆∆o t2g

1 1 0.4 ∆∆∆∆o

d2 t2g2 2 0.8 ∆∆∆∆o t2g

2 2 0.8 ∆∆∆∆o

d3 t2g3 3 1.2 ∆∆∆∆o t2g

3 3 1.2 ∆∆∆∆o

Weak field Strong field

d3 t2g3 3 1.2 ∆∆∆∆o t2g

3 3 1.2 ∆∆∆∆o

d4 t2g3 eg

1 4 0.6 ∆∆∆∆o t2g4 2 1.6 ∆∆∆∆o

d5 t2g3 eg

2 5 0.0 ∆∆∆∆o t2g5 1 2.0 ∆∆∆∆o

d6 t2g4 eg

2 4 0.4 ∆∆∆∆o t2g6 0 2.4 ∆∆∆∆o

d7 t2g5 eg

2 3 0.8 ∆∆∆∆o t2g6 eg

1 1 1.8 ∆∆∆∆o

d8 t2g6 eg

2 2 1.2 ∆∆∆∆o t2g6 eg

2 2 1.2 ∆∆∆∆o

53

0T'STR<u0E./?@\}}~?U?K Ligand '+,@+tC0K?L;:KL=9JOR<JEE?/u0E d-orbital X^,E@+q<tC08WLE.LB?E ;<=.@OJtT-'0LY8@\9/?@TK.Yu0E.?L-ATEXB0/

� D-orbital '+,@+K?L;:Ku0EL=9JOR<JEE?/ '>?1IBK?LKL=U?:u0E e- L0O/TD-W<+:.u0E metal ion \@C-2V/'LEK<@ '>?1IB@+q<tC0:

� 1. LJ�@+\000/; metal ion '+,@+2L=U| +2 1/./?@\}}~? octahedral (high spin cpx.)

*

*

*

*

*

*

*

**

*

*

Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+

LJ�@+\00

0/

Atomic no. .wEu^x/ LJ�@+<9<E (\9BU?K'()�+)

54

�&��� ���� ��Z �9����!��9����&��[\ 2+ !�� transition series 1

Mn = [Ar] 3d5 4s2

Mn2+ = [Ar] 3d5Zn = [Ar] 3d10 4s2

Zn2+ = [Ar] 3d10Ca = [Ar] 4s2

Ca2+ = [Ar]

eg

t2g

eg

t2g

eg

t2gd0 d5 d10

Sc = [Ar] 3d1 4s2

Sc2+ = [Ar] 3d1

t2g t2g t2g

d1

eg

t2g

t2g1 eg0 ---- e- 0:wC1/ t2g X^,E@+ lobe A+x\@CtLEKJOligand '>?1IB e- \@C\9BO9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO e- u0E ligand '>?1IB ligand ]wK9^E-uB?.wC/TD-W<+:.'>?1IBLJ�@+<9<E

55

Ti = [Ar] 3d2 4s2

Ti2+ = [Ar] 3d2

d2

eg

t2g

t2g2 eg0 ---- e- 0:wC1/ t2g X^,E@+ lobe A+x\@CtLEKJOligand '>?1IB 2e- \@C\9BO9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO 2e- u0E ligand '>?1IB ligand ]wK9^E-uB?.wC/TD-W<+:.'>?1IBLJ�@+<9<E

V = [Ar] 3d3 4s2

V2+ = [Ar] 3d3 t2g3 eg0

Cr = [Ar] 3d5 4s1

Cr2+ = [Ar] 3d4

d4

eg

t2g

t2g3 eg1 ---- 1e- 0:wC1/ eg X^,E@+ lobe A+xtLEKJOligand '>?1IB 1e- O9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO 1e- u0E ligand '>?1IBLJ�@+-RT,@

Fe = [Ar] 3d6 4s2

Fe2+ = [Ar] 3d6 t2g4 eg2 -------e-'+,-RT,@1/ t2g :JE-I@o0/KLy+ Ti2+

56

Co2+ = [Ar] 3d7

Ni2+ = [Ar] 3d8t2g5 eg2

t2g6 eg20STO?:-AC/-9+:DKJO Fe2+

Cu2+ = [Ar] 3d9 eg t2g6 eg3 ---- e- '+,-RT,@u^x/0:wC1/ eg X^,E@+ lobe A+xtLEKJO ligand '>?1IB e- O9OJE;LE9^E9w9u0E

t2g

tLEKJO ligand '>?1IB e O9OJE;LE9^E9w9u0E2L=U| + '+,/TD-W<+:.KJO e- u0E ligand '>?1IBLJ�@+-RT,@

57

Jahn-Teller Effect

1937 Jahn & Teller

-Lw2LC?Eu 0E8@-<K|<RDK non-linear X^,E@+ e- 0:wC1/K<|C@ orbital 19 { '+,@+L=9JO E -'C?KJ/tB0EOT9-O+x:D\2 -Ro,0'>?1IBWD?@-'C?KJ/u0EL=9JO E u0E orbital 'JxEI<?:I@9\2 -KT9 orbital '+,@+ E t,>?KDC?-9T@ molecule @+WD?@-.]+:L@?Ku^x/

-8WLE.LB?EOT9-O+x:D--> .@@?tL<9<E ;<=@+K?L;:Ku0E -8WLE.LB?EOT9-O+x:D--> .@@?tL<9<E ;<=@+K?L;:Ku0E degenerate electronic state '+,\@C-.]+:L/Jx/

--9T@RJ/S='JxE 6 u0E M-L :?D-'C?KJ/ -@o,0-KT9 Jahn Teller effect '>?1IB M-L :?D\@C-'C?KJ/ U=-KT9\9B 2 ;OO

1. z-out: Ligand ;/D;K/ z :o9:?D00K\2

2. compression ILo0 z-in: Ligand ;/D;K/ z ]wKI9.Jx/<E\258

K?L-KT9 Jahn Teller Effect

Q -@o,0 ligand 1/;/D;K/ z ]wK:o9:?D00K -D<?-KT9 distortion ./?@\}}~?U?K ligand 1/;/D;K/ z U=/B0:KDC?;K/0o,/

Qd-orbital '+,@+;K/ z -2V/0EWY2L=K0O @+L=9JO E t,>?KDC? d-orbital '+,\@C@+;K/ z -2V/0EWY2L=K0O

-Distort z-out \9B complexes '+,@+ 4 RJ/S=.Jx/ 2 RJ/S=:?D

-Distort z-in \9B complexes '+,@+ 4 RJ/S=:?D 2 RJ/S=.Jx/59

Cu2+ @JK-KT9 Jahn Teller effect

Cu2+ = [Ar] 3d9-----------> t2g6eg3

eg eg

dx2-y2, dz2 dz2 , dx2-y2

t2g t2gdxy , dyz ,dzxdxy , dyz ,dzx

e- 2 tJD1/ dx2-y2 X,EU=O9OJE;LE9^E9w9 Proton '+,/TD-W<+:.u0E metal ion KJO e- u0E ligand @?KKDC?1/;/D;K/ z '+,@+ e- 1 tJD '>?1IB ligand 1/;/D;K/ z ]wK9^E-uB?1K<B metal ion @?KKDC? ligand 1/;/D;K/ xy '>?1IB\9B complexes '+,@+ 4 RJ/S=:?D 2 RJ/S=.Jx/

t2g6eg3 t2g6eg3A B4 ��1 2 ��^� 2 ��1 4 ��^�

e- 2 tJD1/ dz2 X,EU=O9OJE;LE9^E9w9 Proton '+,/TD-W<+:.u0E metal ion KJO e- u0E ligand @?KKDC?1/;/D;K/ xy X,E ligand 1/;/D;K/ xy ]wK9^E-uB?1K<B metal ion @?KKDC?;K/ z '>?1IB\9B complexes '+,@+ 2 RJ/S=:?D 4 RJ/S=.Jx/ (RO@?K)60

Jahn-Teller splitting

z-in z-out

compressed elongatedoctahedron (along the z-axis)

- Spitting energy U=@+ δδδδ1, δδδδ2 < ∆∆∆∆o61

Jahn Teller Distortions

� Orbital degeneracy: for octahedral geometry these are:� t

2g

3eg

1 eg. Cr(II), Mn(III) High spin complexes� t

2g

6eg

1 eg. Co(II) (low spin), Ni(II)� t

2g

6eg

3 eg. Cu(II)� t2g

6eg

3 eg. Cu(II)

� basically, when the electron has a choice between one of the two degenerate e

g orbitals, the geometry will distort to lower the energy

of the orbital that is occupied.� result is some form of tetragonal distortion

� Cu (II) -KT9K?LOT9-O/@?KU/-.@o0/DC?-2V/ Square planar62

Jahn-Teller Effect + Metal (excited state)� 8<I='+,0:wC1/.�?D=/+xU=@+0?:|0:wC.Jx/@?K '>?1IB8WLE.LB?Eu0E cpx. '+,

equilibrium -KT90:wC\9BAJ,D-D<?.Jx/@?K Lw2LC?EOT9-O/\2K<JO@?-2V/;OO-9T@0:C?ELD9-LvD -L+:KDC? �Jahn-Teller effect ;OO dynamic

� \9B spectrum -2V/ band KDB?E \@C@+.@@?tL -AC/ � \9B spectrum -2V/ band KDB?E \@C@+.@@?tL -AC/ � [Ti(H2O)63+] t2g1eg0 ------ex.------> t2g0eg1

� [Fe(H2O)62+] (high spin) t2g4eg2 ------ex.------> t2g3eg3

� [CoF6]3- (high spin) t2g4eg2 ------ex.------> t2g3eg3

63

The color of [Ti(H2O)6]3+

20300 (cm-1)

20300 cm-1 x 1 kJ mol-1 = 243 kJ mol-183.6 cm-1

υ1υ2

* ��� � Jahn Teller effect [�9/ spectra ��� �9��' peak

20300 cm x 1 kJ mol = 243 kJ mol83.6 cm-1

64

Absorption spectrum of K3CoF6 illustrating transitions from the ground state to the Jahn Teller split excited state

65

Dynamic Jahn-Teller effect� q<'?E x-ray crysallography-------Cu2+ 0T00/O?EtJD0o,/ { -AC/ Mn3+ WDL@+;K/ z :?DKDC?

;K/ x ;<= y (t?@I<JK Jahn-Teller effect)� ;tCRODC? [Cu(en)3]2+ ILo0 Mn(acac)3 @+ 6 RJ/S=:?D-'C?KJ/;<= E ;'O\@CtC?EKJ/-<: -/o,0EU?K

2L?K�K?LyY Dynamic Jahn-Teller effect� KLy+ Cu2+ --->RJ/S=1/;K/ z '+,-KT9 Jahn-Teller effect .?@?L];<K-2<+,:/ILo0-2<+,:/\2

@?X^,EKJ/;<=KJ/ (interchange) L=IDC?ERJ/S= Cu-N 'JxE 6� K?L-2<+,:/\2@?0?U-2V/;OO vibration ILo0 rotation� K?L-2<+,:/\2@?0?U-2V/;OO vibration ILo0 rotation� ]B?0JtL?K?L interchange -KT9\9B-LvD@?K U=\@C.?@?L]O0KWD?@;tKtC?Eu0EWD?@:?DRJ/S=1/;K/

tC?E { \9B (\@COT9-O/-<:)� K?L-2<+,:/\2@?L=IDC?ERJ/S= W<B?:KJODC?RJ/S=-KT9K?L rotate \2 900 (pseudorotation)

� pseudorotation ux/KJO T [Cu(H2O)6]2+ (e.s.r. '+, T < 20 K-------tetragonal distortion)

(e.s.r. '+, T >60 K-------Octahedral \@C-KT9 distort -RL?=0JtL?-LvDK?L-KT9 pseudorotation -KT9-LvD@?K)

� Mn(acac)3 or K2Pb[Cu(NO2)6] -2V/tB/

66

Hydrati

on en

ergy (k

J/mol-

1 )

*

**

* **

**

*

* *

**

* ** U?KK?L'9<0E* WC?'+,-0? LSFE 00K;<BD

Thermodynamic !�����:����/� �������!�� d-orbitalHy

drati

on en

ergy (k

J/mol

*

Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+

R<JEE?/'+,-K+,:DuB0E Wo0 CFSE

M2+ + 6H2O [M(H2O)62+(aq) ; E -> Heat of hydration

Ca2+, Mn2+, Zn2+ (d0, d5, d10) @+ CFSE = 0

U|9.+9>?Wo0@+WC? CFSE ≠≠≠≠ 0

-@o,0-0?WC? CFSE @?<OKJO Heat of hydration U=\9BU|9O/-.B/tLE 67

Lattice en

ergy (k

J/mol-

1 )

**

*

* **

** ** U?KK?L'9<0E

* WC?'+,-0? LSFE 00K;<BD

Lattice energyLa

ttice en

ergy (k

J/mol

*

Ca2+ Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2+

R<JEE?/'+,-K+,:DuB0E Wo0 CFSE

Ca2+, Mn2+, Zn2+ (d0, d5, d10) @+ CFSE = 0

U|9.+9>?Wo0@+WC? CFSE ≠≠≠≠ 0

-@o,0-0?WC? CFSE @?<OKJO lattice energy U=\9BU|9O/-.B/tLE68

69

70

Thank you

71