REACTIONS OF FE-III WITH LIALH4 AND LIBH4 IN THE PRESENCE OF BIS(DIPHENYLPHOSPHINO)METHANE (DPPM) AND CO - THE CRYSTAL AND MOLECULAR-STRUCTURES OF TRANS-[FE(CL)(CO)(ETA(2)-DPPM)(2)] [FECL4], TRANS-FE(H)(2)(ETA(2)-DPPM)(2) AND CIS-[FE(ETA(2)-S2CH)(ETA(2)-DPPM)(2)]BF4

Reactions between Fe-III, dppm, CO as appropriate and LiAlH4 produce t he Fe-II complexes trans-[Fe(Cl)(CO)(eta(2)-dppm)(2)][FeCl4]. (1a) tra ns-[Fe(H)(2)(eta(2)-dppm)(2)] (2) and trans-[Fe(H)(Cl)(eta(2)-dppm)(2) ] (3), depending upon the reaction conditions. The trans octahedral st ructures, with chelating dppm ligands, of Ia and 2 have been establish ed by X-ray crystallography. Compound 2 reacts with CO to produce the Fe-0 complex Fe(CO)(3)(eta(1)-dppm)(2) (4), identified by NMR spectrom etry, and with H-2/HBF4 . Et2O to give the dihydrogen complex trans-[F e(H)(eta(2)-H-2)(eta(2)-dppm)(2)]BF4 (5). The dihydrogen can be replac ed with, for example, CO and CH3CN to give trans-[Fe(H)(L)(eta(2)-dppm )(2)]BF4 (L = CO, 6, and L = CH3CN, 7, respectively). With CS2, insert ion into the Fe-bond of 5 occurs to produce the dithioformato complex cis-[Fe(eta(2)-S2CH)(eta(2)-dppm)(2)]BF4 (8), the structure of which i s also reported. (C) 1997 Elsevier Science Ltd.