Bis(2‐amino alcohol‐κ N )dicarboxylatoplatinum( II ) Complexes – Elegant Synthesis via Ring‐Opening of Bis(2‐amino alcoholato‐κ 2 N , O )platinum( II ) Species with Dicarboxylic Acids

Synthesis and purification of bis(2‐amino alcohol‐κ N )dicarboxylatoplatinum( II ) complexes is problematic because of the use of light‐sensitive silver( I ) salts and the competing ring‐closing side‐reactions, especially after release of the chloro‐ or iodo ligands of the dihalogeno starting platinum( II ) species. A novel synthetic procedure, namely selective synthesis of doubly ring‐closed bis(2‐amino alcoholato‐κ 2 N , O )platinum( II ) compounds as the purification step and subsequent coordination of dicarboxylates in the absence of silver( I ) via a ring‐opening reaction, yielded a series of new complexes, which were characterized by elemental analysis, NMR spectroscopy, and X‐ray crystallography. Exemplarily, the ring‐opening of bis(2‐aminoethanolato‐κ 2 N , O )platinum( II ) was performed in the NMR tube by means of oxalic acid and investigated by 1 H and 195 Pt NMR spectroscopy. The reaction was found to be highly efficient: within 3 h complete transformation to the dicarboxylatoplatinum( II ) complex was observed. Contrary, when sodium oxalate was used, no reaction could be detected at all during a period of one day.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)