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§16-2 配位化合物的同分异构现象
The Isomerism of Complexes
一、总论：
1．Definition：凡是化学组成相同的若干配合物，因原子间的连接方式或空间排列方式的不同而引起的结构和性质不同的现象，称为配合物的同分异构现象（isomerism）。
2．Classification
(1) 化学结构异构现象（chemical structure isomerism）：化学组成相同，原
子间的连接方式不同而引起的异构现象，称为化学结构异构现象。例如：
[Co(NH3)5(NO2)]2+和 [Co(NH3)5(ONO)]2+
(2) 立体异构现象（stereo isomerism）：化学组成相同，空间排列不同而引起
的异构现象，称为立体异构现象。例如：Pt(NH3)2Cl2
cis
–
二
氯
·
二
氨
合
铂
(II)
trans - 二氯·二氨合铂(II)
二、化学结构异构现象，大致分为五类：
Ionization isomerism, Hydrate isomerism, Linkage isomerism, Coordination isomerism,
Polymerization isomerism. 1．Ionization 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(NH 3)5Br]SO 4 and [Cr(NH 3)5SO 4]Br 2．Hydrate 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(H 2O)6]Cl 3 ，[Cr(H 2O)5Cl]Cl 2·H 2O ，[Cr(H 2O)4Cl 2]Cl ·2H 2O 3．Linkage isomerism
(1) The first example of this type of isomerism was provided by J φrgensen,
W erner’s
contemporary. His method of preparation was as follows ：
A"solution "Cl]Cl )[Co(NH 23N aN O H Cl
N H 253−−−→−−−→−−−→− red Co(ONO)]Cl )[(NH A"solution "253cold in stand let −−−−−→− yellow )]Cl Co(NO )[(NH A"solution "2253H Cl 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 “structura l i somerism” but inasmuch as all isomerism is basically “structural” , the term linkage isomerism is preferable.
(3) e.g. +252SCN]O)[Cr(H and +252NCS]O)Cr(H [ +]SSO )Co(NH [353 and +S]OSO )[Co(NH 253 4．Coordination isomerism
(1) This may occur only when the cation and anion of a salt are both
complexes, the two isomers differing in the distribution of ligands between the cation and anion
(2) e.g. ]Cr(Ox)][)Co(NH [363 and ]][Co(Ox))[Cr(NH 363 ]][Cr(SCN))[Cr(NH 663 and
](SCN))][Cr(NH (SCN))[Cr(NH 423243
]PtCl ][)[Pt(NH 643 and ]][PtCl Cl )[Pt(NH 4243
(3) Coordination position isomerism
In this form of isomerism the distribution of ligands between two coordination centers differs e.g. and
5．Polymerization isomerism
(1) Strictly speaking, polymerization isomerism, in which n varies in the
complex [ML m ]n is not isomerism. It is included in this list because it represents on additional way in which an empirical formula may give incomplete information about the nature of a complex.
(2) For example, all members of the following series are polymerization isomers:
])(NO )[Co(NH 3233 1=n ])Co(NO ][)Co(NH [6263
2=n ])(NO )][Co(NH )(NO )Co(NH [42232243 2=n
24223253])(NO ))][Co(NH (NO )Co(NH [ 3=n 3422363])(NO )][Co(NH )Co(NH [ 4=n 2623253])Co(NO [)](NO )Co(NH [ 5=n
三、立体异构现象 (Stereo Isomerism ） 1．几何异构现象 (Geometrical isomerism ）
(1) 配合物的配位数与几何构型的关系 (The relationship between
coordination number of complexes and geometrical structure.)
a ．两配位：直线型 (linear) +23)Ag(NH 、-
2CuCl
b ．三配位：平面三角型 (triangle) -][HgI 3
c ．四配位：平面四方 (square planar) -24PtCl ; 正四面体 (tetrahedron)
-
24Zn(CN)
d ．五配位：三角双锥 (trigonal bipyramid) +])[Co(NCCH 53、+I]Cu(dipy)[2
四方锥 (square pyramid) ][VO(acac)2
e ．六配位：正八面体 (octahed ron) 6SF 、-
6PCl
三棱柱 (trigonal prism) ])ph C [Re(S 3222
f ．七配位：五角双锥 (pentagonal bipyramid) ][ZrF Na 73
带帽三棱柱 (the one-face centred trigonal prism) ][ZrF )(NH 734
带帽八面体 (the one-face centred octahedron)
g ．八配位：立方体 (cube) 88H C （立方烷）
四方反棱柱（square anti prism ） ]Zr(acac)[4 十二面体（dodecahedron ） 44[Zr(ox)]-
[ (NH 3)4Co O
O Co(NH 3)2Cl 2 ]2+H
H
[ Cl(NH 3)3Co O O Co(NH 3)3Cl ]
2+
H
H
