Syntheses and solid state structures of cyclic diynes with two chalcogen centres – a competition between weak interactions

Abstract

In this paper we report the synthesis of cyclic diynes of the general formula mX₂n. The letters m and n indicate the lengths of chains between two CC–X units where X indicates S, Se, or Te. The lengths of the bridges vary between m = 4–8 and n = 2–6. Structural investigations by means of X-ray diffraction reveal for most systems a chair-like conformation in the solid state. For 5S₂2, 5S₂3, 7S₂5, 5Se₂2 and 5Te₂3 tubular structures were encountered. These structures can be traced back to weak X⋯X or weak C–H⋯π interactions.