186458-16-2Relevant academic research and scientific papers
Substrate activation by the Wilkinson analogous complex C1Rh(P ～ O)(P O) containing η2 P O-chelated and η1 P-bonded (methoxyethyl) dicyclohexylphosphine as a hemilabile ligand
Lindner, Ekkehard,Keppeler, Berthold,Mayer, Hermann A.,Gierling, Karlheinz,Fawzi, Riad,Steimann, Manfred
, p. 175 - 183 (1996)
In the presence of a variety of small molecules the pseudo 14-electron rhodium complex ClRh(P ～ O)(P O) (1, P O = η2(O,P)-chelated Cy2PCH2CH2OCH3 ligand; P ～ O= η1(P)-coordinated) is shown to undergo a facile cleavage of its intramolecular ether moiety. The reaction of 1 with ethene, diphenylacetylene and carbon disulfide results in the irreversible coordination of the corresponding molecule to the metal yielding the complexes ClRh(C2H4)(P ～ O)2 (2), ClRh(PhC=CPh)(P ～ O)2 (3), ClRhCS2(P ～ O)2 (4), and ClRhCS(P ～ O)2 (5). All compounds are obtained in excellent yields under very mild conditions. The structures of 4 and 5 were determined by single-crystal X-ray diffraction. The oxidative addition of HCl to the starting material 1 leads to the monochelated octahedrally coordinated complex Cl2Rh(H)(P ～ O)(P O) (6). Complex 6 exhibits fluxional behavior on the 31P NMR time scale. Line-shape analysis of variable temperature 31P{1H} NMR spectra of 6 affords the Eyring parameters ΔH? = 42.3kJ mol-1 and ΔS? = -63.7 J mol-1 K-1, indicating an intramolecular exchange mechanism. The Rh-H bond in 6 is able to insert ethene to give the ethylrhodium(III) complex Cl2RhC2H5(P ～ O)2 (7). Subsequently, there follows a fast σ/π rearrangement to the complex Cl2Rh(η2-C2H4)(H)(P ～ O)2 (8) which undergoes a slow π/σ transformation to the monochelated product Cl2Rh(C2H5)(P ～ O)(P O) (9).
