Organoantimony( iii ) compounds containing (imino)aryl ligands of the type 2-(RNCH)C ₆ H ₄ (R = 2′,4′,6′-Me ₃ C ₆ H ₂ , 2′,6′- i Pr ₂ C ₆ H ₃ ): bromides and chalcogenides

The reaction of 2-(RN=CH)C(6)H(4)MgBr [R = 2',4',6'-Me(3)C(6)H(2) (R(1)), 2',6'-(i)Pr(2)C(6)H(3) (R(2))] [prepared from 2-(R(1)N=CH)C(6)H(4)Br (1) or 2-(R(2)N=CH)C(6)H(4)Br (2) and Mg] with SbCl(3) in a 2 : 1 and 1 : 1 molar ratio followed by treatment with an aqueous KBr solution gave [2-(R(1)N=CH)C(6)H(4)](2)SbBr (3) and [2-(R(2)N=CH)C(6)H(4)](2)SbBr (4) as well as [2-(R(1)N=CH)C(6)H(4)]SbBr(2) (6) and [2-(R(2)N=CH)C(6)H(4)]SbBr(2) (7). Treatment of 4 with Na(2)S·9H(2)O provided the dinuclear [{2-(R(2)N=CH)C(6)H(4)}(2)Sb](2)S (5). Heterocyclic species, i.e. the oxide cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbO](3) (8) and the sulfides cyclo-[{2-(R(1)N=CH)C(6)H(4)}SbS](2) (9) and cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2) (10), were obtained by reacting dibromides 6 and 7 with KOH and Na(2)S·9H(2)O, respectively, in a water-toluene solvent mixture. The sulfide 10 reacted with [W(CO)(5)(thf)] to yield the heterometallic complex cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2)[W(CO)(5)] (11). The compounds were characterised by multinuclear NMR spectroscopy in solution, mass spectrometry and IR spectroscopy in the solid state. The molecular structures of 4, 5, 6·CHCl(3), 7, 9·CH(2)Cl(2), 10 and 11·0.25CH(3)OH were established by single-crystal X-ray diffraction. Theoretical calculations using DFT methods were carried out on bromide 7 and the geometrical isomers of its dimer association as well as the geometrical isomers of sulfide 10 and its monomer.