An experimental and theoretical investigation on hypervalent organoselenium(II) halides: Case study of [2-(Et 2NCH 2)C 6H 4]SeX (X = Cl, Br, I)

Abstract

Cleavage of the Se–Se bond in [2-(Et 2NCH 2)C 6H 4] 2Se 2 ( 1) with SO 2Cl 2 (1:1 molar ratio) yielded the organoselenium(II) chloride [2-(Et 2NCH 2)C 6H 4]SeCl ( 2). Treatment of 2 with excess of KX yielded the organoselenium(II) halides [2-(Et 2NCH 2)C 6H 4]SeX [X = Br ( 3), I ( 4)]. The new compounds 2– 4 were characterized by solution NMR spectroscopy ( 1H, 13C, 77Se, 2D experiments). The solid-state molecular structures of 2, 2·HCl and 3 were established by single crystal X-ray diffraction. Distorted T-shaped coordination geometries of type ( C, N)SeX (X = Cl, Br) and CSeCl 2 were found for the neutral halides 2 and 3, and the zwitterionic species [2-{Et 2N +(H)CH 2}C 6H 4]SeCl 2‾ ( 2·HCl), respectively. DFT calculations were performed on 2– 4 and the related tellurium compounds [2-(Et 2NCH 2)C 6H 4]TeX [X = Cl ( 5), Br ( 6) and I ( 7)] in order to elucidate the bond nature and FT-Raman features of this class of organochalcogen(II) derivatives.