On an unusual shortening of the C(sp(3))-C(sp(3)) bonds in n-propylcobaloximes

The structures of two n-propyl cobaloximes, [(n-Pr)Co(Hdmg)(2)(L)]. H2O whe re L = H2O (6) and NH2Ph (7), and Hdmg = monoanion of dimethylglyoxime, are described. The large static disorder undergone by the n-propyl group is at tributed to different conformations of n-Pr, differing in the torsional ang le around the axial Co-L bond. This result contrasts with those reported fo r the anhydrous [(n-Pr)Co(Hdmg)(2)(H2O)] (1) derivative and its inclusion c ompound with alpha-cyclodextrin (2), where a significant lengthening of 0.1 6 Angstrom in the C alpha-C beta bond of n-Pr in 2, with respect to an incr edibly short bond in 1, was attributed to the interaction of the cobaloxime with alpha-cyclodextrin. (C) 2000 Elsevier Science S.A. All rights reserve d.