Solid-state chemistry of molecular metal oxide clusters. Bis(triphenylphosphine)rhodium(I) carbonyl derivatives

Abstract

Hydronium salts of the Keggin-type XM{sub 12}O{sub 40} molecular metal oxide cluster anions SiW{sub 12}O{sub 40}{sup 4{minus}}, SiMo{sub 12}O{sub 40}{sup 4{minus}}, PW{sub 12}O{sub 40}{sup 3{minus}}, PMo{sub 12}O{sub 40}{sup 3{minus}}, PMo{sub 12}O{sub 40}{sup 4{minus}}, and PVMo{sub 11}O{sub 40}{sup 4{minus}} react with ((Ph{sub 3}P){sub 3}Rh(CO))(HC(SO{sub 2}CF{sub 3}){sub 2}) in CH{sub 3}CN{minus}C{sub 2}H{sub 5}OH to form (trans-(Ph{sub 3}P){sub 2}Rh(CO)(CH{sub 3}CN)){sub n}XM{sub 12}O{sub 40}. These salts lose CH{sub 3}CN on heating to provide ((Ph{sub 3}P){sub 2}Rh(CO)){sub n}XM{sub 12}O{sub 40}, which may also be obtained directly from ((Ph{sub 3}P){sub 3}Rh(CO))(HC(SO{sub 2}cF{sub 3}){sub 2}) in pure ethanol. These oxometalates have been characterized by ir, NMR, and x-ray absorption spectroscopy and are considered to contain isolated, lattice-stabilized (Ph{sub 3}P){sub 2}Rh(CO)-(CH{sub 3}CN){sup +} and (Ph{sub 3}P){sub 2}Rh(CO){sup +} cations, with the latter being a three-coordinate, 14-electron Rh(I) species. The activity and selectivity of these compounds as catalysts for olefin isomerization and hydroformylation are described. Reaction of ((Ph{sub 3}P){sub 3}Rh(CO))(HC(SO{sub 2}CF{sub 3}){sub 2}) with CH{sub 3}CN produces (trans-(Ph{sub 3}P){sub 2}Rh(CO)(CH{sub 3}CN))(HC(SO{sub 2}CF{sub 3}){sub 2}). The crystal structure of the triclinic compound is reported. 41 refs., 4 figs., 8 tabs.