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, Bu^t7, Ph 8 or p-MeC₆H₄9; R = CF₃, R′= Bu^t10). 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-SBu^t) core is quite bent with an angle of 55° between the two palladium co-ordination planes.