Infra-red spectra and normal co-ordinate analyses of metal biuret complexes

Two linkage isomers are known for the biuret complexes of Cu(II); the bidentate, O-bonded and the bidentate, N-bonded complexes. In order to characterize them, the i.r. spectra of both forms and their deutero analogues have been obtained from 4000 to 200 cm−1. Normal co-ordinate analyses have been carried out on both complexes to assign the bands as well as to estimate the force constants. The results obtained for these Cu(II) complexes have been applied to the spectra of biuret complexes of other divalent metals. It has been found that Ni(II) also forms two linkage isomers similar to those of Cu(II). The N-bonded Co(II) complex has also been prepared.