Spiers memorial lecture. The quantum chemistry of d- and f-element complexes: from an approximate existence to functional happiness.

The field of modern quantum inorganic chemistry is just over 50 years old, dating back to 1951, when quantitative LCAO molecular orbital theory was developed and ferrocene was discovered. This Lecture provides a survey of the development of the field through about 1980, which has led to its current state. The application of modern quantum chemical techniques are illustrated via two disparate examples from the authors' research group. First, the recent discovery of uranium-noble gas bonds is discussed including the synergy between the theoretical and experimental investigations of this phenomenon. New theoretical results using coupled-cluster [CCSD(T)] methodology is contrasted to the original scalar-relativistic density functional theory results. Second, new applications of time-dependent density functional theory to the rich photochemistry of a dinuclear organometallic complex, (eta5-C5H5)2Fe2(mu-CO)2(CO)2, are discussed.