187Os, 31P and 17O NMR study of carbonylated and alkylated (p-cymene)OsI (L)PR3 complexes
摘要:
Series of complexes of the types [(p-cymene)OsI(CO)PR3][PF6], (p-cymene)OsI(phenylethynyl)PR3, (p-cymene)OsI(alkyl)PR3 have been prepared and investigated by Os-187, P-31 and O-17 NMR spectroscopy. The structures of (p-cymene)OsI(C=CPh)PMe3 (3a) and (p-cymene)OsI(C=CPh)(PPr3)-Pr-i (3c) have been determined by X-ray diffraction. A mechanistic study of the formation of the metallacycle 8A formed by intramolecular trans-alkylation from (p-cymene)(OsI2PPr3)-Pr-i (1c) in the presence of Al2Me6 is presented. As shown by time-dependent P-31 NMR, (p-cymene)OsI(Me)(PPr3)-Pr-i (6c) is formed as an intermediate. Os-187, C-13 coupling constants in Cp-and Cp*Os(CO)(2)Me (14 and 15) have been determined from C-13-filtered (H-1, Os-187)-HMQC correlation spectra and are interpreted in comparison with the Fe-57, C-13 data of the corresponding iron complexes. (C) 1997 Elsevier Science S.A.