μ 3-S bonding mode in H 2M 3(CO) 9S clusters of Ru and Os. An UVPES and theoretical study

Abstract

The electronic structure of H 2M 3(CO) 9S clusters (M = Ru, Os) is discussed on the basis of their He I and He II excited gas-phase photoelectron spectra and on the basis of CNDO quantum mechanical calculations. The PE data clearly demonstrate the cleavage of two direct MM interactions by operation of the bridging hydrides, giving rise to three-center two-electron MHM levels. The μ 3-S bonding mode has been described in detail and compared with previous results on related μ 3-CY cluster derivatives. The CNDO results on Ru 3(CO) 9S =, HRu 3(CO) 9S − and H 2Ru 3(CO) 9S indicate that the μ 3-S—cluster interaction is mostly independent of the presence of the bridging hydrides.