Synthesis and exchange reactions of Ni-dimine-COD, acetylene and olefin complexes.

The complexes MesDADNi(COD) (1), DippDADNi(COD) (2), DippDABNiCOD (3) and DippBIANNi(COD) (5) were readily prepared from Ni(COD)(2). The analogous reaction of the ligand MesBIAN afforded (MesBIAN)(2)Ni (4). The related Ni alkyne complexes DADNi(PhC[triple bond]CPh) (6), DippDABNi(PhC[triple bond]CPh) (7) and DippBIANNi(PhC[triple bond]CPh) (8) are readily prepared by addition of alkyne to solutions of the COD species. The analogous reactions employing tBuDAD ligand with either Ni(COD)(2) alone or Ni(COD)(2) and PhC[triple bond]CPh led only to the known bis-ligand Ni complex, although tBuDADNi(MeCO(2)C[triple bond]CCO(2)Me) (9) is readily prepared. In a similar fashion, the species DippDADNi(MeCO(2)C[triple bond]CCO(2)Me) (10), DippDABNi(Me(3)SiC[triple bond]CSiMe(3)) (11), DippDABNi(MeCO(2)C[triple bond]CCO(2)Me) (12) and DippBIANNi(MeCO(2)C[triple bond]CCO(2)Me) (13) were prepared. Reactions with olefins afforded DippDABNi(MeCO(2)CH=CHCO(2)Me) (14), DippDABNi(MeCO(2)CH=CHPh) (15). Employing isolated (3) or (15) in exchange reactions afforded (7), (11) (14) and (15). Similarly (6) served as a precursor to (10) while (11) reacts with PhC[triple bond]CPh to give (7). The solid state structures of (1), (3)-(7), (9), (11) and (15) are reported.