Reactions of pyridyl donors with halogens and interhalogens: an X-ray diffraction and FT-Raman investigation

Three different N-donors L, namely N -ethyl-N ′-3-pyridyl-imidazolidine-4,5-dione-2-thione (1), N ,N ′-bis(3-pyridylmethyl)-imidazolidine-4,5-dione-2-thione (2), and tetra-2-pyridyl-pyrazine (3), bearing one, two and four pyridyl substituents, respectively, have been reacted with halogens X2 (X = Br, I) or interhalogens XY (X = I; Y = Cl, Br). CT σ–adducts L · n XY, bearing linear N⋯XY moieties (L = 3; X = I; Y = Br, I; n = 2), and salts containing the protonated cationic donors HnLn+ (L = 1 − 3; n = 1, 2, 4), counterbalanced by Cl−, Br−, View the MathML sourceI3-, View the MathML sourceBr3-, View the MathML sourceI5-, View the MathML sourceBr5-, I2Br−, View the MathML sourceI3Br4-, or View the MathML sourceICl2- anions, have been isolated. Among the reactions products, (H1+)Cl−, (H1+)Br−, View the MathML source(H2+)I3-, View the MathML source(H232+)(ICl2-)2, and 3 · 2IBr have been characterised by single-crystal X-ray diffraction. The nature of the products has been elucidated based on elemental analysis and FT-Raman spectroscopy supported by MP2 and DFT calculations.