Hydrogen bonding with sulfur

The hydrogen-bonding capabilities of the sulfur-containing molecule trimercaptotriazine (TMT) was explored using various amines. The amines were chosen to observe the effect of varying base strength on the resulting hydrogen-bonded structures. The specific compounds [pyrrolidineH](+)(2)[HTMT]2-.THF (1), [triethylamineH](+)[H2TMT](-).THF (2), [propylenediamineH(2)](2+)[HTMT](2-) (3), [ethylenediamineH](+)2[HTMT](2-) (4), and [pyridineH](+)[H2TMT](-)(H3TMT.2(pyridine)) (5) were characterized by melting point, elemental analysis, infrared spectroscopy, and X-ray crystallography. It was found that the TMT molecule is readily deprotonated by all of the amines and that the subsequent ammonium hydrogens formed several types of hydrogen bonds. Importantly, these bonds were observed to form with the sulfur atoms of the TMT, with S...N distances of 3.3-3.5 Angstrom.