UNUSUAL ATTRACTIVE INTERACTIONS BETWEEN SELENIUM AND OXYGEN IN SELENOIMINOQUINONES

The reaction of benzeneseleninic anhydride and hexamethyldisilazane gives a reactive intermediate namely oligomeric (RSeN)4 which oxidizes a phenol to the selenoiminoquinone 1. Both spectroscopic and crystallographic studies showed that the oxygen atom of the carbonyl group in the (phenylselenoimino)quinone 2 is involved in an attractive interaction with the selenium atom. The carbon atom of the phenyl ring is also found to be in the same plane as the O-C-C-N-Se plane. Theoretical studies of these systems clearly show a strong dependence of the Se-O interactions on the substituent on the selenium atom. The electronic structure around the selenium atom can be described in terms of the VSEPR model with a 3-center, 4-electron O-Se-R bond and correlated with other hypervalent molecules.