The rhodium(III)trisacetonitrile complexes: A re-investigation of the synthesis of fac- and mer-[RhCl3(CH3CN)(3)], their characterization by 2D NMR spectroscopy and the X-ray crystal structure of mer-[RhCl3(CH3CN)(3)]center dot CH3CN

It is shown that the reaction of RhCl3 . 3H(2)O with acetonitrile normally produces mixtures of mer- and fac-[RhCl3(CH3CN)(3)] (1a and 1b, respectively). The IR and H-1 NMR spectra of these isomers were re-investigated. Their two-dimensional (Rh-103,H-1) NMR spectra were also recorded. Equilibrium and exchange studies of la and Ib in CD,CN were performed. It was found that in la the exchange rate of the nitrile molecule trans to Cl is much faster than those of mutually trans nitriles. Also the nitrile molecules in 1b underwent fast exchange in CD3CN; however, their rate was slightly faster than that of the more labile CH3CN 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.