The quasi-relativistic Xα-SW molecular orbital method in organo-f-element chemistry: applications to UCl4, (η5-C5H5)4U and (η5-C5H5)2UCl2

The advantages and disadvantages of using the Xα scattered-wave molecular orbital method with quasi-relativistic corrections for the calculation of the electronic structure of organo-f-element compounds is discussed. Application of the method in organouranium chemistry is discussed via comparative calculations on UCl₄, (η⁵-C₅H₅)₄U, and (η⁵-C₅H₅)₂UCl₂. It is found that the η⁵-C₅H₅^? ligand is a better donor to U than is Cl^? and that the valence orbitals of (η⁵-C₅H₅)₂UCl₂ are energetically closer to those of (η⁵-C₅H₅)₄U than UCl₄. The calculational results are in excellent accord with experimental photoelectron spectroscopic studies.