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

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 Fdd2, Z = 8, 2 is triclinic, space group PT, Z = 2 and 3 is monoclinic, space group C2/c, Z = 8. The bispyridinium dication in I lies on the special position on the 2-fold axis. Each 3-hydroxymethyl group forms an OH center dot center dot center dot Br hydrogen bond, and the dications combine into three-dimensional networks through numerous CH center dot center dot center dot Br bonds. The IR spectra of the dibromide of 1,3-bis(3-hydroxymethylpyridinium)propane (I) 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. (C) 2018 Elsevier B.V. All rights reserved.