Linkage_isomer
Linkage isomerism
Coordination compounds of the same composition but differing connectivity to ligands
In chemistry, linkage isomerism or ambidentate isomerism is a form of isomerism in which certain coordination compounds have the same composition but differ in their metal atom's connectivity to a ligand.
Typical ligands that give rise to linkage isomers are:
- cyanide, CN− – isocyanide, NC−
- cyanate, OCN− – isocyanate, NCO−
- thiocyanate, SCN− – isothiocyanate, NCS−
- selenocyanate, SeCN− – isoselenocyanate, NCSe−
- nitrite, NO−2
- sulfite, SO2−3
Examples of linkage isomers are violet-colored [(NH3)5Co-SCN]2+ and orange-colored [(NH3)5Co-NCS]2+. The isomerization of the S-bonded isomer to the N-bonded isomer occurs intramolecularly.[1]
The complex cis-dichlorotetrakis(dimethylsulfoxide)ruthenium(II) (RuCl2(dmso)4) exhibits linkage isomerism of dimethyl sulfoxide ligands due to S- vs. O-bonding. Trans-dichlorotetrakis(dimethylsulfoxide)ruthenium(II) does not exhibit linkage isomers.