A new interpretation of the IR bands of supported Rh(I) monocarbonyl complexes.
The characteristic CO vibrational frequency of supported monocarbonyl complexes Rh(I)CO, at 2014 and 1984 cm(-1) on dealuminated Y zeolite and alumina, respectively, is lower than the frequencies of both the symmetric and the antisymmetric CO normal modes of the corresponding stable supported Rh(I) dicarbonyls. The CO mode with a measured frequency between those of the symmetric and antisymmetric CO frequencies of the dicarbonyls, previously assigned to rhodium monocarbonyl, is reassigned to mixed carbonyl dihydrogen complexes Rh(H(2))(CO) or Rh(H)(2)(CO). This reassignment is based on a critical analysis of reported experimental data, supplemented by quantum chemical calculations.
Vayssilov
Georgi N
GN
Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85747 Garching, Germany. gnv@chem.uni-sofia.bg
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