CHARACTERIZATION AND NONRIGID BEHAVIOR OF A CARBOXYLATE-BRIDGED RHODIUM DIMER

s(mu-t-butylacetato)bis(norbornadiene)dirhodium(I) 1 is prepared by a reaction between pivaloyl camphor and (norbornadiene)rhodium(I) chlori de dimer. A molecular rearrangement takes place in which the pivaloyl groups of the pivaloyl camphor starting material are incorporated into the end product as bridging t-butylcarboxylate ligands. A variable te mperature H-1 NMR study and corresponding dynamic computer fit of the NMR data, and crystal structure are reported for the structurally nonr igid dimer. Crystals of 1 are triclinic, a = 10.454(1), b = 10.817(1), c = 12.424(1) Angstrom, alpha = 64.904(7), beta = 100.320(7), gamma = 109.382(8)degrees, Z = 2, space group P $($) over bar$$ 1. The struct ure was solved by heavy atom methods and was refined by full-matrix le ast-squares procedures to R = 0.070 and R(w) = 0.081 for 3093 reflecti ons with I greater than or equal to 3 sigma(l).