E. Lindner et al., CATALYTIC-HYDROGENATION OF CARBON-DIOXIDE WITH THE CATIONIC BIS(CHELATE)RHODIUM COMPLEX [RH(P-O)(2)][BPH4], Inorganica Chimica Acta, 258(1), 1997, pp. 97-100
In contrast to the mono(chelate)rhodium complex CIRh(P similar to O)((
PO)-O-boolean AND) (1) ((PO)-O-boolean AND=eta(2)(O,P)-chelated Cy2PCH
2CH2OCH3 ligand; P similar to O=eta(1)(P)-coordinated) the correspondi
ng cationic bis(chelate) complex [Rh((PO)-O-boolean AND)(2)](+) (anion
:BPh4-) (4) acts as an efficient catalyst for the hydrogenation of car
bon dioxide to produce formic acid. Turnover numbers up to 1000 within
7 h are achieved in methanol solution at 55 degrees C. Stoichiometric
reactions related to the characterization of possible reactive interm
ediates are also presented.