Electrochemical, Theoretical, and Structural Investigations on the “Butterfly” Co4(CO)8L2(RC2R) (L = CO, PPh3; R = H, Et, Ph) Clusters

Domenico Osella, Mauro Ravera, Carlo Nervi, Catherine E. Housecroft, Paul R. Raithby, Piero Zanello, Franco Laschi

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The butterfly clusters Co4(CO)10(RC2R) (R = H, Et, Ph) undergo two consecutive le reduction processes, the former being fully chemically and electrochemically reversible and the latter followed by a moderately fast chemical complication. The disubstituted cluster Co4(CO)8(PPh3)2(HC2H) has been synthesized and its solution- and solid-state structure determined by multinuclear NMR spectroscopy and single-crystal X-ray diffraction: Monoclinic, P21/n (No. 14), a = 11.491 (5) Å, b = 24.178 (8) Å, c = 15.998 (5) Å, β = 105.84 (3)°, V = 4275.9 (9) Å3, Z = 4, RF = 0.061. The substitution of PPh3 for CO has occurred regiospecifically on both wing-tip cobalt atoms. The electrochemistry is qualitatively similar to that of the parent cluster, the reduction potentials being shifted toward more negative values. The strong influence of the substitution of PPh3 for CO and the weak influence of the alkyne substituents on the reduction potentials suggest that the LUMO is metal core in character. This hypothesis is corroborated by ESR results on the radical monoanion and by theoretical calculations within the Fenske-Hall scheme.

Original languageEnglish
Pages (from-to)3253-3259
Number of pages7
Issue number9
Publication statusPublished - 1 Sept 1991

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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