Pt- and Pd-Complexes with Acyclic and Heterocyclic P-Hydroxyaryl-Substituted N-Phosphanylmethyl Amino Acids RP(CH2NHR')2 and (RPCH2NR'CH2)2 – Evaluation of (P^O)M Chelate Formation

Abstract

P-Hydroxyaryl- and N-C6H4COOH-substituted phosphanyl-bis(methylamines) and 1,5-diaza-3,7-diphosphacyclooctanes react with MII(cod)Cl2 (MII = Pt, Pd) to give the corresponding monophosphane L2MCl2 and bisphosphane LMCl2 complexes. Spontaneous mono-(P^O)M-chelate formation was observed only for L2PtCl2 involving 2-C6H4OH groups and, partially, on heating the 8-membered LPtCl2 complex. Addition of excess Et3N led to a full conversion to the (P^O)MCl(P^OH) complexes with COOH groups, whereas heating the LMCl2 complexes with excess Na2CO3 in DMF (4 h 90 °C) led to the formation of sodium salts of mono- and, in trace (Pt) or small (Pd) amounts, of bis(P^O)M-chelates. The structures were established by multinuclear NMR data and for an LPdCl2 and a (P^O)PtCl(P^OH) complex by crystal structure analysis, in the latter case with the influence of a close C–H···Cl–Pt contact on the (P^OH)-conformation.