NMR studies of some second and third row transition metal complexes of monothio-β-diketones

Abstract

A 13C and 19F NMR study of twenty-four ruthenium, rhodium, palladium and platinum complexes containing a difluoromethyl or a trifluoromethyl substitutent(R′) on the monothio-β-diketone, RCSCH 2COR′, is reported. The R-substituents are 2′-thienyl, 2′-naphthyl, phenyl, p-fluorophenyl or p-methylphenyl. The 13C NMR data show the chemical shift of the diketonate ring carbons to be geometry dependent. Similarly, the 19F NMR spectra show chemical shift data which are also metal dependent. The thiocarbonyl and methine carbon's shieldings are also dependent on the nature of the R-group. The rhodium and platinum complexes show carbon-metal and carbon-fluorine spin coupling. The paramagnetic ruthenium(III) complexes give 19F NMR spectral resonances which are broad and shifted upfield from the corresponding diamagnetic rhodium, palladium and platinum complexes. 13C and 19F NMR data supports a facial octahedral geometry for the rhodium(III) complexes.