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Polymorphic crystals of oxacalix[4]arene with 1,3‐alternate conformations of S 4 and C 2 symmetry
Author(s) -
Hori Akiko,
Betsugi Erina,
Ikumura Yoshinori,
Yoza Kenji
Publication year - 2019
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229619001517
Subject(s) - crystallography , ring (chemistry) , chemistry , density functional theory , crystallographic point group , block (permutation group theory) , stereochemistry , aromaticity , symmetry (geometry) , crystal structure , molecule , computational chemistry , combinatorics , geometry , mathematics , organic chemistry
Calix[4]arene and oxacalix[4]arene derivatives have eight possible conformations in the up and down directions of their four aromatic rings from the mean plane of a bridged central ring, the conformations of which determine the functionality of the host frameworks. Despite being a known compound for five decades, oxacalix[4]arene, C 24 H 16 O 4 , has not been characterized previously by crystallographic methods. It crystallizes from hexane/CH 2 Cl 2 solution to give two polymorphs, i.e. prismatic and block‐shaped crystals as twisted 1,3‐alternate structures with S 4 and C 2 symmetry, respectively. These were previously suggested as the prefered stable conformations by density functional theory (DFT) calculations.