Tetrarhodium dodecacarbonyl

Tetrarhodium dodecacarbonyl can effect carbonylation of an olefin at atmospheric pressure (132). The rate of hydroformylation of an olefin decreases with increasing alkyl substitution. 

Liu G, Volken R, Garland M (1999) Unmodified rhodium-catalyzed hydroformylation of alkenes using tetrarhodium dodecacarbonyl. The infrared characterization of 15 acyl rhodium tetracarbonyl intermediates. Organometallics 18(17) 3429-3436... 

Hydridocarbonyl(triphenylphosphine)rhodium readily gives the insertion product (85) with perfluorobut-2-yne, the trifluoromethyl groups being in the cis configuration, in contrast to the molybdenum complex (3) (see p. 293). Two molecules of carbon monoxide are displaced from dodecacarbonyl-tetrarhodium to give (CF3 Cj CF3)Rh4(CO)io. ... 

Important pioneer work in the synthesis of polynuclear metal carbonyls was made by reduction of simple metal salts in the presence of carbon monoxide or similar ligands. The best results are obtained in general for the most stable clusters such as triruthenium, triosmium, tetrarhodium, and tetrairidium dodecacarbonyls. Thus, heterogeneous pyrolysis reactions of metal halides with carbon monoxide in the presence of halide acceptors such as Cu or Zn under relative drastic conditions of temperature and pressure can be used for preparing these types of three and tetranuclear carbonyl clusters ... 

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