Synthesis and structural study of [{Pd(CH₂C₉H₆N)}₂(µ-O₂CR)(µ-X)] complexes (R = Me or CF₃; X = hydroxide, amide or thiolate)

Abstract

The di-µ-carboxylato complexes [{Pd(CH2C9H6N)(µ-O2CR)}2](CH2C9H6N = 8-quinolylmethyl, R = Me or CF3) react in methanol with NaOH(aq)(1 : 1 molar ratio) to give the corresponding mixed hydroxo–carboxylato-bridged complexes [{Pd(CH2C9H6N)}2(µ-OH)(µ-O2CR)](R = Me 1 or CF32). The reactions of 1 or 2 with arylamines or thiols (1 : 1 molar ratio) yielded the corresponding amido- or thiolato-carboxylato complexes [{Pd(CH2C9H6N)}2(µ-O2CMe)(µ-NHR)](R = Ph 3, p-MeC6H44 or p-NO2C6H45) or [{Pd(CH2C9H6N)}2(µ-O2CR)(µ-SR′)](R = Me, R′= Et 6, But7, Ph 8 or p-MeC6H49; R = CF3, R′= But10). The 1H NMR data indicate a cis arrangement of the CH2C9H6N ligands. The crystal structure of complex 10 has been determined. It confirms the cis relationship of the CH2C9H6N ligands. The co-ordination at each palladium atom is approximately square planar and the oxygen atoms of the trifluoroacetate ligands are trans to carbon. The Pd2(µ-OCOCF3)(µ-SBut) core is quite bent with an angle of 55° between the two palladium co-ordination planes.