Some reaction chemistry of trans-[Fe(H)(η2-H2)(η2-dppm)2][BF4].: The crystal and molecular structure of trans-[Fe(H)(CH3CN)(η2-dppm)2][BF4], dppm = bis(diphenylphosphino)methane

Substitution of H-2 by ligands (L) in either pure tians-[Fe(H)(eta(2)-H-2)(eta(2)-dppm)(2)] [BF4], 1, or solutions of [Fe(H)(2)(dppm)(2)] 2, L and HBF4.Et2O in which 1 is made in situ? produce the compounds trans-[Fe(H)(L)(eta(2)-dppm)(2)] [BF4] (L=CH3CN, 3; succinonitrile, 4; pyridine, 5; C2H4, 6; and N-2: 7). The order of H-2 replacement from I appears to be CH3CN>N-2 > C2H4 similar to pyridine. Evidence is presented for the protonation of the hydride ligands of 1 or 2 to produce [Fe(H-2)(2)(eta(2)-dppm)(2)] [BF4](2), 8, although 8 could not be fully characterized nor could it be obtained in the solid state. Trans-[Fe(CH3CN)(2)(eta(2)-dppm)(2)] [BF4](2), 9, was obtained from solutions of 8 treated with acetonitrile. The coordination geometries of 3, 9 and 4 (monodentate succinonitrile) have been confirmed by X-ray crystallography (only the gross structural features of 4 were obtained due to a poor data set from a very small crystal). (C) 1998 Elsevier Science Ltd. All rights reserved.