Synthesis, hydrogen bond interactions and crystal structure elucidation of some stable 2H-imidazolium salts

Reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) with phthalimide, quinazolinedione, thiophenole and 4-pyridinethiole led to the formation of the hydrogen-bonded salts, imidazolium phthalimide (2), imidazolium quinazolinedione (3), imidazolium thiophenolate (4) and imidazolium 4-pyridinethiolate (5), respectively, in good yield. In crystals of 2, the anion is linked to the imidazolium cation by a C-H center dot center dot center dot O hydrogen bond, while in 3 and 5 C-H center dot center dot center dot N hydrogen bonds are observed. In 4, the imidazolium ion is linked to the anion by C-H center dot center dot center dot S hydrogen bonds. In compounds 2, 3 and 5, the interionic hydrogen bonds are close to linearity, while the interionic hydrogen bond angle in 4 is 148.5(9)degrees.