The relevance of the complementary spherical electron density model to organometallic intermediates involved in homogeneous catalysis

The implications of the Complementary Spherical Electron Density Model, originally developed by Mingos and Hawes in 1985 and amplified in 2004, to co-ordinatively unsaturated intermediates in homogenous catalytic processes are discussed. The geometric consequences of the model for 16 and 14 electron complexes are particularly important and are supported by numerous recent X-ray crystallographic investigations. The character of the important frontier orbitals have been explored using density functional calculations.