Synthesis and spectroscopic characteristics of 2-methyl-2-phenylpropyl- and dimethyl(phenyl)silylmethylnickel(II) complexes

Three types of organonickel derivatives, NiR n L m (R = CH 2 CMe 2 Ph, CH 2 SiMe 2 Ph) have been characterized. (1) NiCp(R)L [L = PPh 3 , P(cyclo-C 6 H 11 ) 3 ]; (2) trans -Ni(R)(X)L 2 (X = Cl, L = PMe 3 , PEt 3 , PBu 3 n , PMe 2 Ph); (3) NiR 2 L 2 (L 2 = bipy, Me 2 bipy, Bu 2 t bipy, Me 4 phen, R = CH 2 CMe 2 Ph and CH 2 SiMe 2 Ph; L 2 -= Ph 2 phen, bipym, dppe and L = PMe 3 , R = CH 2 SiMe 2 Ph only). Synthetic strategies and spectroscopic characteristics for these complexes are discussed. In general contrast to their silylmethyl analogues, neophylnickel complexes are labile. NiCp(CH 2 CMe 2 Ph)(L) readily undergoes H-transfer isomerization to give the 2- tert -butylphenyl complex NiCp(2-C 6 H 4 CMe 3 )(L). NiR 2 L 2 (R = CH 2 CMe 2 Ph, L 2 = R' 2 bipy) undergo thermolytic rearrangement also by intramolecular aromatic CH activation to give metallacycles which react further under the prevailing conditions.