Heterocyclic bismuth(III) compounds with transannular S→Bi interactions. An experimental and theoretical approach

Abstract Several new diorganobismuth(III) compounds based on a butterfly-like tetrahydro-dibenzo[ c,f ][1,5] thiabismocine heterocyclic framework were prepared and structurally characterized. The reaction between the dilithio derivative of bis(2-bromobenzyl)sulfane with BiBr 3 in a 1:1 M ratio resulted in the formation of [(C 6 H 4 CH 2 ) 2 S]BiBr ( 1 ). Further exchange reactions of 1 with KI, AgNO 3 and AgOSO 2 CF 3 , respectively, afforded the hypervalent species [(C 6 H 4 CH 2 ) 2 S]BiX [X = I ( 2 ), ONO 2 ( 3 ) and OSO 2 CF 3 ( 4 )]. The new species were characterized by 1 H and 13 C NMR, FT IR spectroscopy and mass spectrometry. The crystal and molecular structures of compounds 1 – 4 were determined by single-crystal X-ray diffraction. In all compounds the sulfur atom is strongly intramolecularly coordinated to bismuth, thus resulting in hypervalent species 10-Bi-4 (for 1 and 2 ) and 12-Bi-5 (for 3 and 4 ). Intermolecular interactions (X…H methylene in 1 and 2 , Bi…C g in 3 and Bi…O in 4 ) led to polymeric chains in the crystals. DFT calculations were carried out on [(C 6 H 4 CH 2 ) 2 S]BiCl and 1 – 4 in order to better understand the S→Bi intramolecular coordination.