SOLUTION STRUCTURES AND ISOMER DISTRIBUTIONS OF BIS(BETA-DIKETONATO) COMPLEXES OF TITANIUM(IV) AND COBALT(III)

Force field parameters for beta-diketonates coordinated to titanium(IV) and cobalt(III) were developed based on published structural data and the cobalt(III) X-ray structures of cis-[Co(acac)2(NH3)2]I.H2O (acac = 2,4-pentanedionate) and [Co(acac)2(en)]ClO4 (en = ethane-1,2-diamine). cis-[Co(acac)2(NH3)2]I.H2O crystallizes in the triclinic space group P1BAR with a = 9.714(3) A, b = 9.885(3) angstrom, c = 10.449(4) angstrom, alpha = 69.12(3)-degrees, beta = 67.83(3)-degrees, gamma = 65.48(2)-degrees, and Z = 2, and the structure was refined to R(W). = 4.2%. [Co(acac)2(en)]ClO4 crystallizes in the monoclinic space group P2(1)/c with a = 12.756(7) angstrom, b = 7.389(2) angstrom, c = 19.76(1) angstrom, beta = 102.55(4)-degrees, and Z = 4, and the structure was refined to R(W) = 4.2%. There is good agreement between calculated and experimental structural data, including an appreciable trans effect in the titanium(IV) structures. A full conformational analysis of various cobalt(III) and titanium(IV) systems leads to calculated isomer distributions that are in satisfactory agreement with the experimental data derived from H-1-NMR spectroscopy.