PENTAMETHYLCYCLOPENTADIENYLRHODIUM BIS-CARBOXYLATES - MONOHAPTO CARBOXYLATE COORDINATION, DIHAPTO CARBOXYLATE COORDINATION, AND WATER COORDINATION TO CP-ASTERISK-RH

摘要

Reaction between [Cp*RhCl2](2) and silver carboxylates in anhydrous, non-coordinating solvents produces Cp*Rh(eta(2)-O(2)CR)(eta(1)-O(2)CR) complexes with the unusual feature of having both the eta(2) and eta(1) carboxylate ligands bound to the same metal. The benzoate complex Cp*Rh(eta(2)-O(2)CPh)(eta(1)-O(2)CPh) was characterized crystallographically and its structure is discussed. Cp*Rh(eta(2)-O(2)CPh)(eta(1)-O(2)CPh) was found to crystallize in the monoclinic space group P2(1)/c with a=11.658(3), b=14.574(4), c=26.248(6) Angstrom, beta=101.87(2)degrees and V=4364(2) Angstrom(3) for Z=8. These bis-carboxylate compounds are very hygroscopic, reacting with water quite readily to form the aquo complexes, Cp*Rh(OH2)(eta(1)-O(2)CR)(2). The acetate aquo complex Cp*Rh(OH2)(eta(1)-O(2)CMe)(2) was characterized crystallographically and was found to crystallize in the monoclinic space group P2(1)/c with a=8.910(2), b=12.854(4), c=14.710(3) Angstrom, beta=106.82(2)degrees and V=1612.6(7) Angstrom(3) for Z=4. The water molecule in Cp*Rh(OH2)(eta(1)-O(2)CMe)(2) was found to internally hydrogen bond to the coordinated acetate groups. The coordination of water in Cp*Rh(OH2)(eta(1)-O(2)CMe)(2) is unusual in that the Rh-O bond is perpendicular to the plane of the water molecule. The geometry of water coordination in these Cp*Rh complexes is compared with geometries found for water coordinated to other non-classical, organometallic compounds. [References: 35]