Syntheses, characterization, and single crystal X-ray analysis of 2-pyridyl aryl selenium (IV) bromides and chlorides

In the present work, a variety of symmetrical and unsymmetrical 2-pyridyl aryl selenium (IV) chlorides or bromides were prepared by the dropwise addition of a dilute solution of bromine or sulfuryl chloride to the corresponding 2-pyridyl aryl selenide in dried organic solvent with continuous stirring at 0 °C. Removal of the solvent under reduced pressure resulted in the synthesis of, 2-pyridyl aryl selenium (IV) bromides or chlorides, respectively, in quantitative yields. The titled dihalides prepared were characterized by elemental analysis, spectroscopic studies, and single crystal X-ray analysis. Single crystal X-ray analysis revealed that the 2-pyridyl aryl selenium (IV) bromides/chlorides have a distorted trigonal bipyramidal structure. The pyridyl and phenyl rings along with a lone pair of electrons on selenium are at equatorial positions whereas chloride/bromide atoms at axial positions of the distorted trigonal bipyramidal structure.