Structures of methyl- and benzyl(η1-azaferrocene)cobaloximes

(I) (eta-1-Azaferrocene-N)bis(dimethylglyoximato-N,N')(methyl)cobalt(III), [Co(FeC9H9N)(C4H7N2O2)2(CH3)], M(r) = 491.22, monoclinic, P2(1)/c, a = 8.539 (3), b = 17.957 (7), c = 14.215 (6) angstrom, beta = 102.54 (4)-degrees, V = 2127.7 angstrom3, Z = 4, D(x) = 1.533 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 14.64 cm-1, F(000) = 1004, room temperature, final R = 0.039, wR = 0.040 for 2948 observed reflections. (II) (eta-1-Azaferrocene-N)benzylbis(dimethylglyoximato-N,N')cobalt(III), [Co(FeC9H9N)(C4h7N2O2)2(C7H7)], M(r) = 567.3 1, triclinic, P1BAR, a = 10.619 (4), b = 11.353 (4), c = 12.693 (5) angstrom, alpha = 85.43 (4), beta = 119.48 (5), gamma = 109.07 (4)-degrees, V = 1252.87 angstrom3, Z = 2, D(x) = 1.503 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 12.49 cm-1, F(000) = 588, room temperature, final R = 0.049, wR = 0.056 for 2285 observed reflections. This work presents X-ray structures of two binuclear cobaloximes, containing axially coordinated azaferrocene. Co-N(ax.) and Co-C bond lengths are discussed and compared with those of other analogs. The structural trans effect of (I) and (II) is analyzed in terms of sigma-donor power and pi-acceptor properties of azaferrocene.