DIAMINOPLATINUM(II) COMPLEXES OF GLUTAMIC-ACID - OBVIOUS CHELATING ISOMERIZATION

Abstract

Coordination isomers of cis-(N-N)Pt(Glu) prepared by reaction of cis-(N-N)Pt(SO4) (N-N=2NH(3). ethylenediamine(en), (R,R)-1,2-diaminocyclohexane (DACH), N,N,N',N'-tetramethylethylenediamine (TMEDA)) with barium glutamate in water have been monitored and characterized by H-1-NMR,C-13-NMR, IR, and mass spectra. The reaction at room temperature affords the mixture of O,O'- and N,alpha O-chelated platinum(II) complexes. The O,O'-chelate initially formed isomerized to N,alpha O-chelate on standing for a long time or increasing temperature. The ratio of the two isomers at room temperature depends on the nature of the nitrogen donor coligand (N-N).