New chiral organoantimony(iii) compounds containing intramolecular N → Sb interactions – solution behaviour and solid state structures

Abstract

Hypervalent organoantimony(III) compounds of the type [2-(Me2NCH2)C6H4]PhSbCl (1), [2-(Me2NCH2)C6H4]MesSbBr (7) and [2-(Me2NCH2)C6H4]nAr(3-n)Sb [n = 1, Ar = Ph (4), Mes (9); n = 2, Ar = Ph (5), Mes (10)] were prepared via salt elimination reactions between [2-(Me2NCH2)C6H4]Li and MesMgBr and PhnSbCl(3-n), [2-(Me2NCH2)C6H4]SbBr2 or [2-(Me2NCH2)C6H4]nSbCl(3-n) (n = 1, 2), in appropriate molar ratios. Halogen exchange reactions with aqueous KBr or KI gave [2-(Me2NCH2)C6H4]ArSbX [Ar = Ph, X = Br (2), I (3); Ar = Mes, X = I (8)]. Metathesis reaction between 1 and MesMgBr affords [2-(Me2NCH2)C6H4]PhMesSb (6). Compounds 1-10 were investigated by means of NMR (1H, 13C) in solution and by mass spectrometry. The investigation of the molecular structures of 2-8 by single-crystal X-ray diffraction revealed that the nitrogen atoms of the pendant CH2NMe2 arms are strongly coordinated to the antimony atoms. All compounds exhibit chirality and crystallize as racemic mixtures.