Structural elucidation of liquid cyclooctatetraene and cyclooctadienes in inclusion crystals

• Published in: Journal of molecular structure Vol. 1221; p. 128775
• Main Authors: Kawahata, Masatoshi, Tominaga, Masahide, Komatsu, Ai, Hyodo, Tadashi, Yamaguchi, Kentaro
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-12-2020
• Subjects: Channel structure; Crystal engineering; Host-guest system; Inclusion crystal; Molecular recognition; Molecular recognition; Crystal engineering; Inclusion crystal; Host-guest system; Channel structure
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.128775

A disubstituted adamantane derivative having chloropyrimidine units (1) was utilized as a V-shaped host molecule to create inclusion crystals and to elucidate the molecular structures of the guests by X-ray crystallographic analysis. The crystallization of 1 and 1,3,5,7-cyclooctatetraene (a) in chloroform resulted in the formation of co-crystal (1a) with 2:3 host:guest complexation stoichiometry. Host 1 was assembled into a molecular network composed of double layer structures bearing channels where guest molecules (a) were accommodated. Co-crystals (1b, 1c) containing 1,3-cyclooctadiene (b) and 1,5-cyclooctadiene (c) were obtained at identical stoichiometry under similar conditions. The host molecules arrangement in both 1b and 1c was similar to that of 1a. In each case, guest molecules b and c were accommodated in the channels formed between the layers of the host molecules. In all co-crystals, the molecular structures of the guests a‒c, along with the host frameworks, were determined by crystallographic analysis.
•A V-shaped compound was useful as a host molecule for co-crystal formation.•X-ray crystallographic analyses of four co-crystals were performed.•The co-crystals exhibited network structures containing cyclooctatetraene or cyclooctadiene.•The structures of liquid cyclooctatetraene and cyclooctadiene were determined.