Metal complexes of benzodiazepines. Part 3. Synthesis and characterization of organometallic complexes of platinum(II)

Abstract

The complexes cis-[PtMe₂(Me₂SO)L¹] and [PtR₂L²](R = Me or Ph) are easily obtained by reaction in CH₂Cl₂ of the complexes [PtMe₂(Me₂SO)₂] or [{PtPh₂(Et₂S)}₂] with L¹= 2,3-dihydro-2,2,4-trimethyl-1H-1,5-benzodiazepine or L²= bromazepam = 7-bromo-1,3-dihydro-5-(2-pyridyl)-2H-1,4-benzodiazepin-2-one. They are the first examples of simple organometallic adducts of benzodiazepines with platinum(II). Their ¹H and ¹³C NMR spectra suggest the co-ordination of L¹ through N⁵, while L² acts as a bidentate ligand by means of the imine and pyridine nitrogen atoms. The co-ordinated heterocyclic rings show a notable increase in their inversion barrier.