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-[(PR 3 ) 2 (X)Ni-YNi(X)(PR 3 ) 2 ] {X = Cl, Br; H 2 Y = 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 NaN 3 with the dinuclear Ni(II)-thiophene chlorides gave the corresponding Ni(II)-azido complexes, trans,trans-, whose reactivity toward trimethylsilyl pseudohalides such as trimethylsilyl isothiocyanates and cyanides was investigated. In addition, the reaction of trans-[BrNi(PEt 3 ) 2 -C 4 H 2 S-C 4 H 2 S-CHO], a thienyl Ni(II) complex containing a terminal aldehyde group, with phosphonium ylide was examined.