An. Krylov et al., HYDROGEN-BONDS AND PROTONATION OF CARBONYL-CONTAINING POLYNUCLEAR RHODIUM COMPLEXES, Russian chemical bulletin, 44(2), 1995, pp. 378-379
According to IR spectroscopy data, the interaction of bi-, tri-, and t
etranuclear cyclopentadienylcarbonyl rhodium complexes with rather wea
k protic acids (phenols, fluoroalcohols) in low-polarity media results
in the formation of hydrogen bonds of the OH...O=C type with bridged
carbonyl groups. According to H-1 NMR data, protonation of these compl
exes with strong acids (CF3COOH and HBF4) occurs at the the Rh-Rh bond
to give the symmetrical [GRAPHICS] bridge.