Chapter 16
Chapter 16The Coordination Compounds
169317041760
1793TassaertCoCl6NH3B.M.TassaertNaOHNH3H2OCoCl2(aq)NH3H2OCo2+CoOCo(OH)2CoCl36NH3
(( A. Werner S. M. Jogensen189125Werner
1primary valencesecond valence,inner(outer
2Werner [Co(NH3)4Cl2]+
[Co(NH3)4Cl2]+
3
3
2
2
Werner[Co(NH3)4Cl2]Cl[Co(NH3)4Cl2]+Werner1913
((
16-1
The Basic Concepts of Complexes
Definition of Coordination Compounds
NH3H2OXH2CCH2
(
C
r
)
(
F
e
)
+
]
)
[Ag(NH
2
3
-
2
4
]
PtCl
[
Composition of Coordination Compounds
1innerouterFe(CO)5 Pt(NH3)2Cl2
2centerligand
(1) ddsM
(2) (L)
Classification
1Classical complexes
+
2
3
)
Ag(NH
-
3
4
Cu(CN)
2-complexes
2
5
5
)
H
Fe(C
)]
H
C
(
K[PtCl
4
2
3
Zeises salt
M
H
2
C
C
H
2
M
M
2 4 6
M
C5H5Cp FeCp2
M
5
5
5
H
C
-
h
C5H55
-
5
5
H
C
6C5H5 1
M
C5H53
5
5
3
H
C
-
h
H
M
C5H511 ( C5H5
5
5
H
C
-
H2CCHCH2
MCH2CHCH2( C3H5
M
3 ( C3H5
LLigand
1
N
(1) unidentate ligand
NH3H2OX (py)
(2) multidentate ligand(chelate
2
(1) XF(fluoro)Cl(chloro)Br(bromo)I(iodo)H2O (aquo)
CO (carbonyl)NO (nitrosyl)C5H5N (py)OH (hydroxo)
(2) en () H2NCH2CH2NH2ethylenediamine
O
C
O
C
O
O
H
2
N
C
H
2
C
O
O
ox2( oxalate ion gly(
N
N
bipy 2,2-dipyridyl
(3) EDTA(H4Y)
H
O
O
C
H
2
C
N
C
H
2
C
H
2
N
H
O
O
C
H
2
C
C
H
2
C
O
O
H
C
H
2
C
O
O
H
ethylenediaminetetracetato
Coordination Number
1
2 = =
/
3EANEffective atomic number rule
(1)
aEAN365486
b + =18(n ( 1)d10ns2np6
c (n ( 1)dnd1ns3np9
(2)
aFe(CO)x(NO)y 8 + 2x + 3y = 18
x = 5y = 0x = 2y = 2
b
4
HCo(CO)
-
4
Co(CO)
4
Co(CO)
18e (stable) 18e (stable) 17e (unstable)
c
Mn(CO)5 17e2Mn(CO)5 Mn2(CO)10Co(CO)42Co(CO)4 Co2(CO)8
(
C
5
H
5
)
(
O
C
)
M
n
M
n
(
C
O
)
(
C
5
H
5
)
O
O
C
C
x
d
C
l
(
O
C
)
4
W
W
(
C
O
)
4
C
l
C
l
C
l
x
18
2
1
6
4
2
1
=
+
+
+
+
+
x
18
1
1
7
2
5
=
+
+
+
+
+
x
x = 0 x = 2
e
4
5
5
)
H
Fe(C
-
2
10
3
3
]
CO)
(
Re
H
[
F
e
H
H
R
e
H
C
O
R
e
R
e
C
O
C
O
C
O
H
H
O
C
O
C
O
C
O
C
C
O
C
O
f
Re2O7 + 17CORe2(CO)10 + 7CO2
F
e
(
C
O
)
3
+ Fe(CO)2 + 2CO
Cr(CO)6 + 4NOCr(CO)4 + 6CO
The Nomenclature of Coordination Compounds
1
(1) [Cr(H2O)4Cl2]Cl()
(2)
a[Co(NH3)5Br]SO4()
bK3[Fe(CN)6]()
2
(1) + + + ()
[PtCl2(NH3)(C2H4)]()()
(2)
a
b
cNH3H2ONH3
dNH3NH2OHNH3
(3)
a
mono() di() tri() tetra() penta()
hexa() hepta() octa() nona() deca()
bMSCN ((SCN) thiocyano
MNCS ((NCS) isothiocyano
C
l
F
e
C
l
C
l
C
l
F
e
C
l
C
l
MNO2 ((NO2) nitro HO NO2
[
(
N
H
3
)
C
r
O
H
C
r
(
N
H
3
)
5
]
C
l
5
MONO ((ONO) nitrito H ONO
NO nitrosyl CO carbonyl
MCN cyano M NC isocyano
3
3
3
2
3
Fe(CO)
CO)
Fe(
(OC)
-
m
( - )[(0 )]
M
a
a
( - )[( )]
M
O
O
C
C
O
O
[( )]
16-2
The Isomerism of Complexes
1Definitionisomerism
2Classification
(1) chemical structure isomerism
[Co(NH3)5(NO2)]2+ [Co(NH3)5(ONO)]2+
(2) stereo isomerismPt(NH3)2Cl2
[
C
l
(
N
H
3
)
3
C
o
O
O
C
o
(
N
H
3
)
3
C
l
]
2
+
H
H
[
(
N
H
3
)
4
C
o
O
O
C
o
(
N
H
3
)
2
C
l
2
]
2
+
H
H
cis (II) trans - (II)
Ionization isomerism, Hydrate isomerism, Linkage isomerism, Coordination isomerism,
Polymerization isomerism.
1Ionization isomerism
(1) Two coordination compounds which differ in the distribution of ions between those directly coordinated and counter-ions present in the crystal lattice are called ionization isomers.
(2) e.g. [Cr(NH3)5Br]SO4 and [Cr(NH3)5SO4]Br
2Hydrate isomerism (Solvent isomerism)
(1) Hydrate isomerism is similar to ionization isomerism except that an uncharged ligand changes from being coordinated to a free-lattice position whilst another ligand moves in the opposite sense.
(2) e.g. [Cr(H2O)6]Cl3 [Cr(H2O)5Cl]Cl2H2O [Cr(H2O)4Cl2]Cl2H2O
3Linkage isomerism
(1) The first example of this type of isomerism was provided by J(rgensen, Werners
contemporary. His method of preparation was as follows
A"
solution
"
Cl]Cl
)
[Co(NH
2
3
NaNO
HCl
NH
2
5
3
red
Co(ONO)]Cl
)
[(NH
A"
solution
"
2
5
3
cold
in
stand
let
yellow
)]Cl
Co(NO
)
[(NH
A"
solution
"
2
2
5
3
HCl
conc
heat
(2) It deals with a few ligands (ambidenatate) that are capable of bonding through are type of donor atom in one situation not a different atom in another complex. Some authors refer to this type of isomerism as structural isomerism but inasmuch as all isomerism is basically structural , the term linkage isomerism is preferable.
(3) e.g.
+
2
5
2
SCN]
O)
[Cr(H
and
+
2
5
2
NCS]
O)
Cr(H
[
+
]
SSO
)
Co(NH
[
3
5
3
and
