Organorhodium compound
Organorhodium chemistry is the chemistry of organometallic compounds containing a rhodium-carbon chemical bond, and the study of rhodium and rhodium compounds as catalysts in organic reactions.
Stable organorhodium compounds and transient organorhodium intermediates are used as catalyst such as in olefin hydroformylation, olefin hydrogenation, olefin isomerization and the Monsanto process
Organometallic rhodium compounds share many characteristics with those of cobalt (see organocobalt compounds), which is also in group 9. Rhodium can exist in oxidation states of -III to +IV, but rhodium(I) and rhodium(III) are the most common. Rhodium(I) compounds (d8 configuration) can occur with square planar or trigonal bipyramidal geometries, while rhodium (III) compounds (d6 configuration) typically have an octahedral geometry.
Important homoleptic rhodium compounds are tetrarhodium dodecacarbonyl, Rh4(CO)10, and hexadecacarbonylhexarhodium, Rh6(CO)16. Both are important catalysts in hydroformylation of alkenes, often accompanied by a phosphine ligand, though Rh6(CO)16 is less preferred due to its relatively poor solubility:
Nitrobenzene reduction is another reaction catalysed by this compound type:
Cyclooctadiene rhodium chloride dimer [RhCl(COD)]2 is investigated for its use in C-H bond activation. Cyclopentadienyl complexes of rhodium include the Sandwich compound rhodocene and half-sandwich compounds [(η5-Cp)Rh(CO)2] and Pentamethylcyclopentadienyl rhodium dichloride dimer.
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