Theory and importance of oxygen bridge-bonding

Abstract

An oxygen atom as a donor bridge causes the bonding of two atoms at lower electronegativity. In a case of paramagnetic centres such as transition metal ions the magnetic criterion occurs, i.e. spin queuehing follows. The MO model for the Single oxygen bridge bonding in Ru 4 +, W 4 +, Mo 5 +, Fe 3 +, Re 4 +, Cr 3 +, Os 4 + dimers of d 4 , d\ d 2 , d 1 and d 5 electronic structure were calculated using the SCCC method. This model gives a good explanation of magnetic properties of all the known complexes with one linear or angular bridge. The influence of other ligands on the ground term and on the complex properties has been explained. The structures most convenient to linear bridge formation are those ofthe d 0 -d 4 electronic ones. At d 5 the angular bridge is more enocgetically convenient. Double oxygen-bridge bondingwas studied on the large group of Mo-V dimers. The probable MO system explaining their magnetic properties is given. The spectroscopic characteristic in the infra-red of single and double oxygen bonding confirmed the bonding of the oxygen bridge.