One-pot synthesis of manganese(I) and rhenium(I) alkylcarbonato complexes, fac-(CO)3(dppp)MOC(O)OR. Possible trapping of intermediate diphosphine dimers, [(CO)3(dppp)M]2

The reactions of Mn2(CO)10 and Re2(CO)10 with dppp, where, dppp is 1,3-bis(diphenylphosphino)propane, in primary alcohols, yielded the corresponding hydrides, fac-(CO)3(dppp)MH under argon atmosphere. However, similar reactions of the metal carbonyls with diphosphines in alcohols in the presence of air or carbon dioxide afforded one equivalent of the corresponding hydrides, fac-(CO)3(dppp)MH and one equivalent of the alkylcarbonato complexes, fac-(CO)3(dppp)MOC(O)OCH2R. The rhenium propylcarbonato complex, fac-(CO)3(dppp)ReOC(O)OCH2CH2CH3 is very stable and has been characterized by X-ray crystal structure determination. The manganese-analog, fac-(CO)3(dppp)MnOC(O)OCH2CH2CH3 is moisture-sensitive and converted slowly to the known carbonato-bridged complex, (CO)3(dppp)MnOC(O)OMn(dppp)(CO)3.