Reduction of CO2 and SO2 with low valent nickel compounds under mild conditions

The reaction of [(dippe)Ni(mu-H)](2) (A) (dippe = 1,2-bis(diisopropyl-phosphinoethane) with CO2 in toluene afforded the carbonyl nickel(0) compounds of the type {(dippe) Ni(CO)](2)(mu-dippe)}(1) and (dippe)Ni(CO)(dippe=O)] (2), which were characterized by standard spectroscopic methods; complex (1) was also characterized by single crystal X-ray diffraction. Reaction of (A) with SO2 yields the thiosulfate nickel(II) compound [Ni(dippe)(S2O3)] (5), which was fully characterized by standard spectroscopic methods and X-ray crystallography. In both cases, a reduction reaction of CO2 to CO and SO2 to S2O32- with (A) took place under mild conditions.