Formation of T-shaped versus charge-transfer molecular adducts in the reactions between bis(thiocarbonyl) donors and Br2 and I2.

The reactions of 4,5,6,7-tetrathiocino-[1,2-b:3,4-b']-1,3,8,10-tetrasubstituted-diimidazolyl-2,9-dithiones (R-2,R'(2)-todit; 1: R=R'=Et; 2: R=R'=Ph; 3: R=Et, R'=Ph) with Br-2 exclusively afforded 1: 1 and 1: 2 "T-shaped" adducts, as established by FT-Raman spectroscopy and single-crystal X-ray diffraction in the case of complex 1 center dot 2Br(2). On the other hand, the reactions of compounds 1-3 with molecular I-2 provided charge-transfer (CT) "spoke" adducts, among which the solvated species 3 center dot 2I(2 center dot)(1-x)I(2 center dot)xCH(2)Cl(2) (x=0.94) and (3)(2 center dot)7I(2 center dot)xCH(2)Cl(2), (x= 0.66) were structurally characterized. The nature of all of the reaction products was elucidated based on elemental analysis and FT-Raman spectroscopy and supported by theoretical calculations at the DFT level.