Spectroscopic, structural and theoretical investigation of 1,3-bis(3-hydroxymethylpyridinium)propane dibromide, tetrabromozincate and tetrabromocuprate

Abstract The structures of 1,3-bis(3-hydroxymethylpyridinium)propane dibromide ( 1 ), 1,3-bis(3-hydroxymethylpyridinium)propane tetrabromozincate ( 2 ) and 1,3-bis(3-hydroxymethylpyridinium)propane tetrabromocuprate ( 3 ) have been studied by X-ray diffraction, DFT, FTIR, NMR and UV–vis methods. The crystal structures of three analogous compounds are significantly different: 1 is orthorhombic, space group Fdd 2, Z = 8, 2 is triclinic, space group P 1 ¯ , Z = 2 and 3 is monoclinic, space group C 2 /c , Z = 8. The bispyridinium dication in 1 lies on the special position on the 2-fold axis. Each 3-hydroxymethyl group forms an OH⋯Br hydrogen bond, and the dications combine into three-dimensional networks through numerous CH⋯Br bonds. The IR spectra of the dibromide of 1,3-bis(3-hydroxymethylpyridinium)propane ( 1 ) and its tetrabromometallates ( 2 and 3 ) were compared and their interpretation was confirmed by calculated spectra. UV–vis spectra for tetrabromocuprate salt ( 3 ) showed significant differences between solid-phase and water solution.