title: 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 C triple bond C-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 5S(2)2, 5S(2)3, 7S(2)5, 5Se(2)2 and 5Te(2)3 tubular structures were encountered. These structures can be traced back to weak XX or weak C-Hpi interactions.
authors.affiliation: Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: J Hilko
authors.initials: JH
authors.lastname: Schulte
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Werz
authors.forename: Frank
authors.initials: F
authors.lastname: Rominger
authors.forename: Roll
authors.initials: R
authors.lastname: Gleiter