1,2-Bis[(pyridin-2-ylmethyl)sulfanyl]ethane and its dimorphic hydrochloride salt.

Although having been described as a liquid in the literature for 41 years, 1,2-bis[(pyridin-2-ylmethyl)sulfanyl]ethane, C(14)H(16)N(2)S(2), (I), has now been obtained as monoclinic crystals via a new and convenient method of purification. Molecules of (I) are located on crystallographic inversion centres and are held together by C-H···N and C-H···S interactions, resulting in the formation of a three-dimensional network structure. In addition, two polymorphs of the corresponding hydrochloride salt, 2-[({2-[(pyridin-1-ium-2-ylmethyl)sulfanyl]ethyl}sulfanyl)methyl]pyridin-1-ium dichloride, C(14)H(18)N(2)S(2)(2+)·2Cl(-), (II) and (III), have been isolated. Molecules of (II) and (III) have similar conformations and are located on inversion centres. Both polymorphs form three-dimensional networks through N-H···Cl, C-H···Cl and C-H···S interactions. The structure of (III) displays voids of 35 Å(3).