Interactions in Molecular Crystals, 123. Crystallization and Structure of Donor–Acceptor Complexes between Rigid or Conformationally Flexible Thio-Crowns and Iodine

✍ Scribed by Bock, Hans ;Nagel, Norbert ;Seibel, Andreas

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 900 KB
• Volume: 1997
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199719971018

✦ Synopsis

Abstract

Studies of π and σ interactions in molecular crystals of donoracceptor complexes have stimulated interest in the crystallization and structure determination of {1,3,5‐trithiane…︁I~2~}, {1,5,8,12‐tetrathiocyclotetradecane…︁I~2~} and {1,4,7,10,13,16‐hexathiocyclooctadecane…︁(I~2~)~3~} in order to detect structural changes. The II bond lengths are stretched by up to 0.16 Å relative to the gas‐phase value and prove iodine to be the acceptor species. Additional distance data >S…︁I~2~ and II from the Cambridge Structural Database establish a nonlinear correlation. In contrast, bond lengths and bond angles of the sulphide donors remain largely unperturbed on complexation, even when considerable conformational changes are observed. For example, on addition of four iodine molecules, the rather flexible 18‐thio‐crown‐6 with a C~2~‐symmetric bowl‐shape is flattened to a C~s~‐symmetric rectangle. The structural results complement those reported for stronger acceptor effects of metal cations.