复旦大学物理化学课件20

Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2. Metal-ligand π interactions MetalTaking 12 π-type orbitals of the ligands as bases:
Γπ = T1g ⊕ T1u ⊕ T2 g ⊕ T2u
d5
d6
d7
6
Chemistry Department of Fudan University
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
4. Jahn-Teller Effect JahnAny non-linear ion or molecule which nonis in an orbitally degenerate term will distort to relieve this degeneracy.
Orbital of Central Metal Atom
s px py pz
d 2 z2 − x2 − y2 d 2 2 x −y
A1 g
T1 u
Eg
dxy, dyz, dxz
2011-12-28 Chemistry Department of Fudan University
T2g
12
Physical Chemistry I
Ligand Orbitals
1 (φ1 + φ2 + φ3 + φ4 + φ5 + φ6 ) φ A1 g = 6 1 (2φ5 + 2φ6 − φ1 − φ2 − φ3 − φ4 ) φE = 12 1 φ E g = (φ1 + φ 2 − φ 3 − φ 4 ) 2 1 1 1 (φ5 − φ6 ) φT = (φ1 − φ2 ) φT = (φ3 − φ4 ) φT =
2011-12-28
Chemistry Department of Fudan University
16
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
T1* u
p
* A1 g
s
d
E
T2 g
* g
M
Eg
L
T1u
A1 g
2011-12-28 Chemistry Department of Fudan University 17
2011-12-28 Chemistry Department of Fudan University 2
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Weak field complexes: ∆ < P (high spin) Strong field complexes: ∆ > P (low spin)
Chapter V Polyatomic Molecular Structure
2011-12-28
Chemistry Department of Fudan University
20
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Chapter V Polyatomic Molecular Structure
2011-12-28
Chemistry Department of Fudan University
13
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2011-12-28
Chemistry Department of Fudan University
1
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
3. Crystal field stabilization energy
The crystal field stabilization energy is defined as the energy by which a complex is stabilized due to the splitting of the d-orbitals. It is determined by Pairing Energy(P) and Splitting Energy( ∆ )
ψ = ∑ CM φM + ∑ CLφL
2011-12-28
Chemistry Department of Fudan University
11
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
1. Metal-ligand σ interactions Metal-
e g* 10Dq t2g
eg* 10Dq t2g*
Case b
t2g t2g
2011-12-28 Chemistry Department of Fudan University 22
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2. Unsaturated Hydrocarbon Complex
2011-12-28
Chemistry Department of Fudan University
24
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
5. The Applications of CFT ￭The model can be used to understand, interpret and predict the magnetic behavior, colors and some structures of coordination complexes. ￭ But does not explain the bonding in coordination complexes.
2011-12-28
Chemistry Department of Fudan University
9
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
The most serious defect of the CFT model is that it does not recognize the existence of overlap, and hence the existence of specific bonding interactions, between the ligands and the metal orbitals. orbitals.
d9
4
Chemistry Department of Fudan University
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
high spin for d4-d7 octahedral complex
d4
2011-12-28
2011-12-28
Chemistry Department of Fudan University
3
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Electron Arrangement
d1 d2
2011-12-28
d3
d8
t2g*
Case a
t2g eg* 10Dq t2g e g* 10Dq t2g
2011-12-28 Chemistry Department of Fudan University 21
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
d5
d6
d7
5
Chemistry Department of Fudan University
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Low spin for d4-d7 octahedral complex
d4
2011-12-28
g
1u
2
1u
2
1u
2
2011-12-28
Chemistry Department of Fudan University
15
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
The metal-ligand σ bonding in an metaloctahedral complex
d d
7
d d
9
9
7
t 2 g → Small eg → L arg e
2011-12-28
Distortion Distortion
Chemistry Department of Fudan University
8
wk.baidu.com
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2011-12-28
Chemistry Department of Fudan University
10
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
§5-4-2. Molecule Orbital Theory (MOT) LCAO-MO
§5-4-3. σ-π bonding complexes π
1. Carbonyl Complex
2011-12-28
Chemistry Department of Fudan University
23
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2011-12-28
Chemistry Department of Fudan University
7
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
For octahedral coordination
High Spin d 1 d 2 d 4 d 6 Distortion Low Spin d 1 d 2 d 4 d 5
Taking 6 σ-type orbitals of the ligands as bases:
Γσ = A1g ⊕ E g ⊕ T1u
2011-12-28
Chemistry Department of Fudan University
14
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
2. Spectrochemical Series I- < Br- < Cl- < SCN- < NO3- < F- < OH< H2O < NCS- < gly < Py < NH3 < en < NO2- < PPH3 < CN- < CO
1 y x x y = (π 3 + π 4 + π 5 + π 6 ) 2
1 y = (π 5 + π 6x + π 1x + π 2y ) 2
Chemistry Department of Fudan University 19
φ
φ
yz T2 g
xz T2 g
2011-12-28
Physical Chemistry I
2011-12-28
Chemistry Department of Fudan University
18
Physical Chemistry I
Chapter V Polyatomic Molecular Structure
Ligand Orbitals
φ
xy T2 g
1 y x x y = (π 1 + π 2 + π 3 + π 4 ) 2