SYNTHESIS AND STRUCTURE OF (COBALT)3C CLUSTERS WITH ALKYNE FUNCTIONALITY

Tricobalt carbon clusters with alkyne functionality R(C = C)(n)CCo3(CO)9 (R = Me3Si, n = 1, 2; R = Ph, (eta(5)-C5H5)Fe(eta(5)-C5H4) (Fc), and H, n = 1) have been prepared by Cadiot-Chodkiewicz, Grignard, or AlCl3-assisted coupling reactions between an alkyne and BrCCo3(CO)9. The scope for these reactions has been delineated. X-ray structure analysis of the compounds Me3SiC = CCCo3(CO)9 (P1BAR, a = 9.261 (2) angstrom, b = 15.092 (6) angstrom, c = 15.739 (8) angstrom, alpha = 76.12 (4)-degrees, beta = 88.33 (3)-degrees, gamma = 77.73 (2)-degrees, Z = 4), FcC = CCCo3(CO)9 (P2(1)2(1)2(1), a = 11.658 (3) angstrom, b = 13.826 (3) angstrom, c = 14.625 (3) angstrom, Z = 4), and Me3Si(C = C)2CCo3(CO)9 (P1BAR, a = 9.117 (3) angstrom, b = 9.386 (4) angstrom, c = 15.191 (4), alpha = 95.40 (3)-degrees, beta = 93.42 (3)-degrees, gamma = 93.38 (3)-degrees, Z = 2) have assisted spectroscopic characterization. The structural analysis of Me3Si(C = C)2CCo3(CO)9 revealed the presence of polymeric material in the crystal, consistent with topochemical polymerization of the monomer units in the solid state. Co2(CO)6 derivatives of these clusters (R = Me3Si, Ph) are minor products and have been independently synthesized from the alkyne clusters; regioisomers of Me3Si(C = C)2[Co2-(CO)6]CCo3(CO)9 were identified.