STEPWISE DEPROTONATION OF H4RU4(CO)12 - HIGH-YIELD SYNTHESIS AND C-13 NMR-SPECTRA OF H3RU4(CO)12- AND H2RU4(CO)122-

A stepwise, systematic procedure is described for the deprotonation of H4Ru4(CO)12 when it is treated with KH in THF. Reaction with 1 equiv of KH yields the previously reported H3Ru4(CO)12- ion; reaction with 2 equiv of KH yields the new anion H2Ru4(CO)122-“; and reaction with 3 equiv of KH yields an equimolar mixture of H2Ru4(CO)122- and Ru4(CO)124-. In this last reaction, the HRu4(CO)123- ion is believed to form initially and then decompose to the products which were isolated. Carbon-13 NMR spectra and infrared spectra of the H2Ru4(CO)122- ion indicate the presence of carbonyl bridging. The carbon-13 NMR spectrum under conditions of slow exchange (-80°C) indicates that this dianion is of Cs point symmetry. From infrared and carbon-13 NMR spectra of the potassium and (PPh3)2N+salts of H2Ru4(CO)122- significant ion pairing is suggested in THF solutions of the potassium salt. © 1979, American Chemical Society. All rights reserved.