Synthesis and structure of interaction products of quinoline-2(1H)-thione with molecular iodine

Abstract

The behavior of quinoline-2(1H)-thione, which is a potential antithyroid drug toward molecular iodine, was investigated. The ability of quinoline-2(1H)-thione to form the outer-sphere charge-transfer complex C9H7NS·I2 with iodine molecular in dilute chloroform solution has been studied by UV–vis spectroscopy (lgβ=3.85). The crystal structure of the new salt 2-(quinoline-2-yldisulfanyl)quinolinium triiodide – product of irreversible oxidation of quinoline-2(1H)-thione was determined by X-ray diffraction. The 2-(quinoline-2-yldisulfanyl)quinolinium cations form dimers through π–π–stacking interaction between quinoline rings. Strong intramolecular interactions are observed between iodine – sulfur atoms and iodine – hydrogen atoms with shortened contacts (less of sum of van der Waals contacts). It is noteworthy that two perfectly centrosymmetrical anions I3− form a very short contact I(3)⋯I(3′) 3.7550(5) so we can state the formation of the dianion I62−. Therefore the formation and topology of polyiodide species depend on the characteristics, such as shape, size and charge, etc., of the counter cation, 2-(quinoline-2-yldisulfanyl)quinolinium, which is considered as templating agent.