Ma. Banares et al., EFFECT OF PRECURSOR CORE STRUCTURE ON THE HYDROGENATION OF 1,3-BUTADIENE CATALYZED BY CLUSTER-DERIVED MODEL CATALYSTS, Chemistry of materials, 7(3), 1995, pp. 553-561
The cobalt-carbonyl cluster ligand based complexes, M(2){mu-[(CO)(9)Co
-3(mu(3)-CCO2)]}(4), M = Mo, Cu, were converted into active solids by
thermolysis. These precursor complexes contain a square planar array o
f tricobalt clusters centered by a M(2) carboxylate bridged core which
is M-M bonding in the case of M = Mo and nonbonding in the case of M
= Cu. TGA, TPD-MS, XPS, BET, and in situ DRIFTS measurements demonstra
te the existence of two forms of the resulting materials as well as di
fferences in these materials due to precursor structure. The first, fo
rmed at 400 K, is designated LT-MCo, M = Mo, Cu, and results from part
ial decarbonylation of the precursor with retention of metal carboxyla
te linkages. The second, formed at 500 K is designated HT-MCo and resu
lts from the full decarbonylation of the precursor and, under H-2, ful
l decarboxylation. The catalytic activity of these materials for the h
ydrogenation of 1,3-butadiene was studied. Significant differences in
the activities and selectivities for the LT- and HT-MCo materials are
observed and demonstrate a dependence of catalytic behavior on molecul
ar precursor core structure.