Metal complexes of benzodiazepines. Kinetic properties of bromazepam toward square planar dimethyl sulfoxide complexes of platinum(II) and palladium(II)
The kinetics of substitution reactions of Me(2)SO from the complexes [MX(2)(Me(2)SO)(2)] (M=Pt, X=Cl CH3, cis; M=Pd, X=Cl, trans) by the ligands bromazepam or bipy have been investigated in Me(2)SO and/or CH2Cl2 at 25 degrees C. The results are interpreted in terms of an associative mechanism for cis-[PtCl2(Me(2)SO)(2)] and a dissociative mechanism for cis-[PtMe(2)(Me(2)SO)(2)]. The substitution reaction for the complex trans-[PdCl2(Me(2)SO)(2)] proceeds without retention of stereochemistry; a consecutive displacement mechanism or a pseudo-rotation mechanism can be operative. The kinetic behaviour of bromazepam and bipy is very similar.