TY - JOUR
T1 - Electrochemical, Theoretical, and Structural Investigations on the “Butterfly” Co4(CO)8L2(RC2R) (L = CO, PPh3; R = H, Et, Ph) Clusters
AU - Osella, Domenico
AU - Ravera, Mauro
AU - Nervi, Carlo
AU - Housecroft, Catherine E.
AU - Raithby, Paul R.
AU - Zanello, Piero
AU - Laschi, Franco
PY - 1991/9/1
Y1 - 1991/9/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0000809590&partnerID=8YFLogxK
U2 - 10.1021/om00055a049
DO - 10.1021/om00055a049
M3 - Article
AN - SCOPUS:0000809590
SN - 0276-7333
VL - 10
SP - 3253
EP - 3259
JO - Organometallics
JF - Organometallics
IS - 9
ER -