Metal-Proton Interactions in Benzylamine Complexes of Palladium(II): The Effect of Methyl Substitution at Nitrogen and the Role of the Interaction During Cyclopalladation. X-Ray Crystal Structure of Tetrabenzylaminepalladium(II) Acetate Chloride

Article abstract of DOI:10.1071/CH9842179

Reaction of Pd(O2CMe)2 with PhCH2NH2 leads to either Pd(NH2CH2Ph)2(O2CMe)2 or 2.The X-ray crystal structure of shows pairs of ²⁺ ions held together by hydrogen bonds from the NH proton to chlorine and oxygen atoms of the anions, and the absence of interactions between phenyl ring ortho protons and the metal.PhCH2NHMe reacts with Pd(O2CMe)2 giving Pd(NHMeCH2Ph)2(O2CMe) and PhCH2NMe2 gives the cyclometallate 2. 1H n.m.r. spectra indicate that the complexes Pd(NMe2CH2Ph)(L)(O2CMe)2 (L=PhNH2, o-MeC6H4NH2) prepared from 2, contain an interaction of the benzylamine ortho aromatic protons with the metal whereas Pd(NHMeCH2Ph)(L)(O2CMe)2 (L=o-MeC6H4NH2) does not. 1H n.m.r. analysis of PdCl4^2- and PhCH2NMe2 in (2H1) methanol at 400 MHz indicates a 1:1 reaction stoichiometry and metal-proton interactions in intermediates containing above-plane and in-plane geometry of the aromatic ring, before metallation takes place.A 400-MHz spectral analysis of Pd(O2CMe)2 and PhCH2NMe2 in CDCl3 suggests similarly orientated species arise in the reaction giving 2.