Impact of the anion and chalcogen on the crystal structure and properties of 4, 6‐dimethyl‐2‐pyrimido(thio)nium halides. Issue 5 (24th April 2020)

• Record Type: Journal Article
• Authors: Okuniewski, Andrzej; Rosiak, Damian; Chojnacki, Jarosław
• Is Part Of: Acta crystallographica. Volume 76:Issue 5(2020)
• Page Start: 468
• Page End: 475
• Publication Date: 2020-04-24
• Subjects: pyrimidone -- pyrimidinethione -- anion–π interactions -- chalcogen interactions -- halides -- crystal structure; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229620005525
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : Seven new 4, 6‐dimethyl‐2‐pyrimido(thio)nium halides were synthesized and characterized. In the discussion, they are compared to three chloride derivatives described previously in the literature. In these ten compounds, hydrogen‐bond patterns form chains, ribbons or layers. Four compounds exhibit luminescent properties. Abstract : By the reaction of urea or thiourea, acetylacetone and hydrogen halide (HF, HBr or HI), we have obtained seven new 4, 6‐dimethyl‐2‐pyrimido(thio)nium salts, which were characterized by single‐crystal X‐ray diffraction, namely, 4, 6‐dimethyl‐2‐oxo‐2, 3‐dihydropyrimidin‐1‐ium bifluoride, C6 H9 N2 O + ·HF2 − or (dmpH)F2 H, 4, 6‐dimethyl‐2‐oxo‐2, 3‐dihydropyrimidin‐1‐ium bromide, C6 H9 N2 O + ·Br − or (dmpH)Br, 4, 6‐dimethyl‐2‐oxo‐2, 3‐dihydropyrimidin‐1‐ium iodide, C6 H9 N2 O + ·I − or (dmpH)I, 4, 6‐dimethyl‐2‐oxo‐2, 3‐dihydropyrimidin‐1‐ium iodide–urea (1/1), C6 H9 N2 O + ·I − ·CH4 N2 O or (dmpH)I·ur, 4, 6‐dimethyl‐2‐sulfanylidene‐2, 3‐dihydropyrimidin‐1‐ium bifluoride–thiourea (1/1), C6 H9 N2 S + ·HF2 − ·CH4 N2 S or (dmptH)F2 H·tu, 4, 6‐dimethyl‐2‐sulfanylidene‐2, 3‐dihydropyrimidin‐1‐ium bromide, C6 H9 N2 S + ·Br − or (dmptH)Br, and 4, 6‐dimethyl‐2‐sulfanylidene‐2, 3‐dihydropyrimidin‐1‐ium iodide, C6 H9 N2 S + ·I − or (dmptH)I. Three HCl derivatives were described previously in the literature, namely, 4, 6‐dimethyl‐2‐oxo‐2, 3‐dihydropyrimidin‐1‐ium chloride, (dmpH)Cl, 4, 6‐dimethyl‐2‐sulfanylidene‐2, 3‐dihydropyrimidin‐1‐ium chloride monohydrate, (dmptH)Cl·H2 O, and 4, 6‐dimethyl‐2‐sulfanylidene‐2, 3‐dihydropyrimidin‐1‐ium chloride–thiourea (1/1), (dmptH)Cl·tu. Structural analysis shows that in 9 out of 10 of these compounds, the ions form one‐dimensional chains or ribbons stabilized by hydrogen bonds. Only in one compound are parallel planes present. In all the structures, there are charge‐assisted N + —H… X − hydrogen bonds, as well as weaker CAr + —H… X − and π + … X − interactions. The structures can be divided into five types according to their hydrogen‐bond patterns. All the compounds undergo thermal decomposition at relatively high temperatures (150–300 °C) without melting. Four oxopyrimidinium salts containing a π + … X − …π + sandwich‐like structural motif exhibit luminescent properties.