Synthesis, structure and thermal rearrangement of tetramethyldisilane-bridged bis(cyclopentadienyl) diiron complexes with a phosphite or phosphine ligand substitution

Photolysis of tetramethyldisilane-bridged bis(cyclopentadienyl) tetracarbon yl di-iron in the presence of phosphite or phosphine ligand afforded the co rresponding Fe-Fe bond complexes with one carbonyl replaced by a phosphite or phosphine ligand: [(Me2SiSiMe2)Cp2Fe2(CO)(PR3)(mu-CO)(2)] (R=OPh, 1; OEt , 2; Ph, 3). When these complexes were heated in refluxing xylene, they bec ome rearranged to the corresponding products [(Me2SiCpFe)(2)(CO)(3)(PR3)] ( R=OPh, 4; OEt, 5; Ph, 6). It was found that, after phosphite or phosphine l igand substitution, the rearrangement became facile. The molecular structur es of 1-6 were characterized by IR, H-1 NMR spectra and elemental analyses. The crystal structures of 1 and 4 were determined by X-ray diffraction ana lysis. (C) 1999 Elsevier Science Ltd. All rights reserved.