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

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.