Synthesis and characterization of new platinum(II) phosphinate complexes

Abstract

The syntheses of platinum(II) complexes of bis(dimethylphosphinylmethylene)amine and bis(aminomethyl)phosphinic acid were investigated. In the case of bis(dimethyl-phosphinylmethylene)amine the reaction with K₂[PtCl₄] yields the potassium amino-trichloroplatinate K[PtCl₃L] (L = bis(dimethylphosphinylmethylene)amine), which was characterized by multinuclear (¹H, ¹³C, ³¹P, and ¹⁹⁵Pt) NMR spectroscopy in solution. Bis(aminomethyl)phosphinic acid reacts with K₂[PtCl₄] under strictly controlled pH conditions to give colorless crystals of the cisplatin analog K[PtCl₂L′] (L′ = bis(aminomethyl)phosphinate). This complex was characterized by multinuclear NMR spectroscopy in solution as well as by single-crystal X-ray diffraction in the solid state. The bis(aminomethyl)phosphinate coordinates to platinum via both amino functions, thus acting as a chelating ligand.

Keywords:

• Platinum(II) complexes
• Single-crystal X-ray diffraction
• Multinuclear NMR spectroscopy
• Aminophosphinate ligands
• Cisplatin analog

Acknowledgments

We are grateful to the Excellence Initiative at LMU Munich – LMU excellent for the financial support of this study. Thanks are also due to Dr Karin Lux (LMU Munich) for the help with the structure solution of 6. The authors highly acknowledge the National Science Fund of Bulgaria (National Centre for Advanced Materials (UNION), Module 2: New materials in medicine and pharmacy, Contract No. DCVP 02-2/2009) for the financial support.