Abstract
The reaction of TaMe(3) Cl(2) with the rigid acridane-derived trisamine H(3) NNN yields the tantalum(V) complex [TaCl(2) (NNN(cat) )]. Subsequent reaction with dioxygen results in the full four-electron reduction of O(2) yielding the oxido-bridged bimetallic complex [{TaCl(2) (NNN(sq) )}(2) O]. This dinuclear complex features an open-shell ground state due to partial ligand oxidation and was comprehensively characterized by single crystal X-ray diffraction, LIFDI mass spectrometry, NMR, EPR, IR and UV/VIS/NIR spectroscopy. The mechanism of O(2) activation was investigated by DFT calculations revealing initial binding of O(2) to the tantalum(V) center followed by complete O(2) scission to produce a terminal oxido-complex.