Synthesis and characterization of fluorophenylpalladium pincer complexes: electronic properties of some pincer ligands evaluated by multinuclear NMR spectroscopy and electrochemical studies

Palladium fluorophenyl complexes with different pincer ligands Pd(Ar)[2,6-(tBu(2)PCH(2))(2)C6H3] (13), Pd(Ar)[2,6-(tBu(2)PO)(2)C6H3] (14), Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C5H2}Fe(C5H5)] (15), and Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C5H2} Ru(C5H5] (16) were synthesized by the reaction of LiAr (Ar = C6H4F-4) with the respective trifluoroacetate palladium pincer complexes 9-12. The molecular structures of 14 and 16 were determined by an X-ray crystallographic method. Complexes 13-16 and {Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C5H2}Fe(C5H5)]}PF6 (17) were studied by multinuclear NMR spectroscopy and cyclic voltammetry. On the basis of F-19 NMR chemical shifts and (1)J(C-13-F-19) coupling constants, as well as Pd-II/Pd-IV oxidation potentials, electronic characteristics of the corresponding pincer ligands were elucidated.