High-resolution structural study on pyridin-3-yl ebselen and its N-methylated tosylate and iodide derivatives

Abstract

The crystal structure of the pyridine-substituted benzisoselenazolinone 2-(pyridin-3-yl)-2,3-dihydro-1,2-benzoselenazol-3-one (C12H8N2OSe, 2), related to the antioxidant ebselen [systematic name: 2-phenyl-1,2-benzoselenazol-3(2H)-one, 1], is characterized by strong intermolecular N⋯Se( - N) chalcogen bonding, where the N⋯Se distance of 2.3831 (6) Å is well within the sum of the van der Waals radii for N and Se (3.34 Å). This strong interaction results in significant lengthening of the internal N - Se distance, consistent with significant population of the Se - N σ*antibonding orbital. Much weaker intermolecular O⋯Se chalcogen bonding occurs between the amide-like O atom in 2 and the less pol..