Cyclopalladated complexes with 9-anthraldehyde aroylhydrazones: Synthesis, properties and structures

Reactions of equimolar amounts of Li2PdCl4, 9-anthraldehyde 4-R-benzoylhydrazones (H2Ln; n = 1 and 2 for R = H and NMe2, respectively) and CH3COONa·3H2O in methanol produce the cyclopalladated complexes with the formula [Pd(HLn)Cl] (1 (R = H) and 2 (R = NMe2)). Reactions of [Pd(HLn)Cl] (1 and 2) with 2 mol equivalents of PPh3 in acetone provide the complexes of formula [Pd(Ln)(PPh3)] (3 (R = H) and 4 (R = NMe2)). Complexes 1–4 have been characterized by elemental analysis and spectroscopic (IR, UV–vis, fluorescence and NMR) measurements. Molecular structures of 1–4 have been confirmed by X-ray crystallography. In [Pd(HLn)Cl] (1 and 2), the C,N,O-donor (HLn)− and the chloride form a CNOCl square-plane around the metal centre, while (Ln)2− and the PPh3 assemble a CNOP square-plane around the metal centre in [Pd(Ln)(PPh3)] (3 and 4).