Substituted cyclopentadienyl compounds: III. NMR and molecular orbital study of conformational preferences in some substituted (η5- cyclopentadienyl)-rhodium(η4-diene) compounds and the crystal structure of (η5-methanoylcyclopentadienyl)- (η4-2,3-dimethoxybutadiene)rhodium(I)☆

摘要: The crystal structure of (eta-C5H4CHO)Rh(eta74-C4H4(OMe)2) (I) has been determined by X-ray diffraction. preferred orientation the ligands is one in which cyclopentadienyl ring substituent bond bisects internal carbon-carbon counter diene ligand. Related compounds for four separate resonances appear have analysed nOe difference NMR spectroscopy and spectral simulation. results show that relative solution similar to revealed crystallographic studies. CNDO/U molecular orbital calculations performed on several these compounds. are consistent with experimental findings there a preference rotamer tendency towards allyl-ene geometry. Carbon-13 studies ratios carbon chemical shifts metal-diene coupling constants reflect importance retrodative bonding.