Spin-orbit coupling geometry

Buhr et al. described the photocycloaddition of methyl and ethyl trimethyl pyruvates (25) with diisopropyl-1,3-dioxole. In contrast to the reaction with ethyl pyruvate, the bicyclic oxetane 26 was formed with very high (>98%) diastereoisomeric excess. An x-ray analysis revealed the unusual endo-t-butyl configuration. Semi-empirical calculation indicated that this clearly is the kinetic product formed by a biradical combination reaction, which might be controlled by favorable spin-orbit coupling geometries. 

Calculation of the Slater-Condon, spin-orbit coupling and ligand field parameters. The luminescence of CsMgBr3 Eu2+ is crucially dependent on the local coordination geometry of the Eu2+ dopant. Besides, a geometry change occurs in the excited state 4f 5d1 (see Table 2), leading to shifts... 

The sterically demanding ligand N(SiMe3)2 has allowed the electronic and EPR spectra of the first row rf-block elements in a purely trigonal planar environment to be measured.112113 All of the data obtained by Bradley et al. on this series were consistent with the theoretical predictions for this geometry, and allowed in some cases values for spin-orbit coupling constants to be evaluated. 

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