THE RHODIUM(III)TRISACETONITRILE COMPLEXES - A REINVESTIGATION OF THESYNTHESIS OF FAC-[RHCL3(CH3CN)(3)] AND MER-[RHCL3(CH3CN)(3)], THEIR CHARACTERIZATION BY 2D NMR-SPECTROSCOPY AND THE X-RAY CRYSTAL-STRUCTUREOF MER-[RHCL3(CH3CN)(3)]CENTER-DOT-CH3CN

It is shown that the reaction of RhCl3 . 3H(2)O with acetonitrile norm ally produces mixtures of mer- and fac-[RhCl3(CH3CN)(3)] (1a and 1b, r espectively). The IR and H-1 NMR spectra of these isomers were re-inve stigated. Their two-dimensional (Rh-103,H-1) NMR spectra were also rec orded. Equilibrium and exchange studies of la and Ib in CD,CN were per formed. It was found that in la the exchange rate of the nitrile molec ule trans to Cl is much faster than those of mutually trans nitriles. Also the nitrile molecules in 1b underwent fast exchange in CD3CN; how ever, their rate was slightly faster than that of the more labile CH3C N in 1a. The X-ray crystal structure of mer-[RhCl3(CH3CN)(3)]. CH3CN ( 1c) was determined. Crystal data: triclinic space group <P(1)over bar> , a=12.200(10), b=12.227(10), c=12.270(11) Angstrom, alpha=115.95(7), beta=101.52(7), gamma=102.93(6)degrees, V=1509(2) Angstrom(3), Z=4.