coordination complexes

Coordination complexes

[CoCl2(en)2]Cl dichlorobis(en)cobalt(III) chloride

Co

Cl

Cl

N

N

N

Ntrans-

Co

ClN

N

Cl

N

N

cis-

Co

Cl

Cl

N

N

N

N

Co

Cl N

N

Cl

N

N

same

enantiomers

Coordination complexes

Na[FeCl4]

sodium tetrachloroferrate(III)

coordination number 4

tetrahedral square planar

Fe

Cl

Cl

Cl

Cl

(rare)

no geometric isomers

optical isomers

[Pt(NH3)2Cl2]

diamminedichloroplatinum(II)

Pt

Cl

Cl NH3

NH3

PtCl

Cl NH3

H3N

cis

trans

no optical isomers

Bonding

localized electron model octahedral d 2sp3

square planar dsp2

tetrahedral sp3

linear sp

predicts shapes

does not predict colorsmagnetic properties

Crystal Field Model

Crystal Field Model

dz2 dx

2-y

2 dxy dyz dxz

electrostatic repulsion ligand lone pair e-

d-orbital electronscrystal field splitting

colors

colors

400 nm

430 nm

490 nm

560 nm

580 nm

620 nm

800 nm

E = hc

= h

dz2 dx

2-y

2

dxy dyz dxz

[Ti(H2O)6]3+

t2g

eg

h

510 nm

red

spectrochemical series

CN- > NO2- > en > NH3> H2O > F-> OH- > Cl- > Br- > I-

strong fieldlarge

weak fieldsmall as charge increases, increases

t2g

eg

t2g

eg

spectrochemical series

CN- > NO2- > en > NH3> H2O > F-> OH- > Cl- > Br- > I-

strong fieldlarge

weak fieldsmall

[Zn(en)3]2+

colorless

Sc3+d10 d0 high spin d5

weakly colored

colors

low spin high spin

colorscoordination number = 4

dz2 dx

2-y

2 dxy dyz dxz

tet =

tetrahedral

49oct

always high spin

square planar

dxzdyz

dz2

dxy

dx2

-y2

colorscoordination number = 2 linear

dz2

dyz dxz

ligands along z-axis

dx2

-y2dxy

magnetic properties

compounds with unpaired e- paramagnetic

Guoy balance

spectrochemical series

CN- > NO2- > en > NH3> H2O > F-> OH- > Cl- > Br- > I-

strong fieldlarge

weak fieldsmall

[Fe(CN)6]4- [Fe(H2O)6]2+

eg

t2g

eg

t2g

diamagnetic paramagnetic

magnetic properties

compounds with unpaired e- paramagnetic

Guoy balance

spectrochemical series

CN- > NO2- > en > NH3> H2O > F-> OH- > Cl- > Br- > I-

strong fieldlarge

weak fieldsmall

for ≤ 5 unpaired e-

(BM) = n(n+2)

[Fe(H2O)6]2+

eg

t2g

µ = √ 24

µ = 4.90

Coordination Complexes

mineral

animal

vegetable

yes

yes

yes

20 Questions

Fe2+

+ O2

strong field

- O2

weak field

red blue