Synthesis and Reactivity of Dinuclear Ni(II) Azido Complexes Containing Bithienylene or Terthienylene Bridging Ligands

Abstract

Dinuclear Ni(II)-thiophene halides, which contain linear bridging thienylenes, trans,trans-[(PR3)(2)(X)Ni-Y-Ni(X)(PR3)(2)] {X = Cl, Br; H2Y = 5,5'-dichloro-2,2'-bithiophene (H(2)bth); H(2)tth = 5,5 ''-dichloro-2,2':5',2 ''-terthiophene (H(2)tth)} were prepared by the oxidative addition of dihalobithiophene (H(2)bth) or dihaloterthiophene (H(2)tth) to [Ni(COD)(2)] in the presence of tertiary phosphines. Subsequent reactions of NaN3 with the dinuclear Ni(II)-thiophene chlorides gave the corresponding Ni(II)-azido complexes, trans,trans-[(PR3)(2)(N-3)Ni-Y-Ni(N-3)(PR3)(2)], whose reactivity toward trimethylsilyl pseudohalides such as trimethylsilyl isothiocyanates and cyanides was investigated. In addition, the reaction of trans-[BrNi(PEt3)(2)-C4H2S-C4H2S-CHO], a thienyl Ni(II) complex containing a terminal aldehyde group, with phosphonium ylide was examined.