SYNTHESIS AND STEREOCHEMISTRY OF PENTACARBONYL(PHOSPHOLE)METAL(0) AND TETRACARBONYLBIS(PHOSPHOLE)METAL(0) COMPLEXES OF 6B ELEMENTS


OZER Z., OZKAR S.

PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS, cilt.70, ss.339-349, 1992 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 70
  • Basım Tarihi: 1992
  • Doi Numarası: 10.1080/10426509208049183
  • Dergi Adı: PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
  • Sayfa Sayıları: ss.339-349

Özet

Pentacarbonylphospholemetal(0) and cis-tetracarbonylbis(phosphole)metal(0) complexes were synthesized from the thermal reaction of M(CO)5(THF) and M(CO)4(COD) (M: Cr, Mo, W) with corresponding phosphole (1-phenyl-3,4-dimethylphosphole, 1-phenyl-3-methylphosphole, and 1-phenylphosphole). These complexes were isolated as orange crystals by column chromatography on silicagel at 253 K and crystallization from n-hexane at 223 K and characterized by means of IR and NMR (H-1, C-13, and P-31). Spectroscopic data shows that the phosphole is coordinated to the transition metal through its phosphorus atom rather than through the conjugated diene unit in the both types of complexes. The tetracarbonylbis(phosphole)metal(0) complexes were found to have cis-arrangement of two phosphole ligands. Comparing C-13-NMR chemical shifts of the complexes with the free ligands, one can deduce that the involvement of the phosphorus atom in the ring pi-electron delocalization is drastically reduced upon coordination. This is attributed to the stronger sigma-donation but weaker pi-accepting ability of the phosphorus atom in the phosphole ligands compared to the carbonyl groups.