title: Cyclotetrabenzoin: Facile Synthesis of a Shape-Persistent Molecular Square and Its Assembly into Hydrogen-Bonded Nanotubes.
abstract: Cyanide-catalyzed benzoin condensation of terephthaldehyde produces a cyclic tetramer, which we propose to name cyclotetrabenzoin. Cyclotetrabenzoin is a square-shaped macrocycle ornamented with four α-hydroxyketone functionalities pointing away from the central cavity, the dimensions of which are 6.9×6.9 Å. In the solid state, these functional groups extensively hydrogen bond, resulting in a microporous three-dimensional organic framework with one-dimensional nanotube channels. This material exhibits permanent-albeit low-porosity, with a Langmuir surface area of 52 m(2)  g(-1) . Cyclotetrabenzoin's easy and inexpensive synthesis and purification may inspire the creation of other shape-persistent macrocycles and porous molecular crystals by benzoin condensation.
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA).
authors.forename: Qing
authors.initials: Q
authors.lastname: Ji
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA).
authors.forename: Ha T M
authors.initials: HT
authors.lastname: Le
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA).
authors.forename: Xiqu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Center for Advanced Radiation Source (ChemMatCARS), The University of Chicago, c/o APS/ANL, 9700 South Cass Drive, Argonne, IL 60439 (USA).
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA).
authors.forename: Tatyana
authors.initials: T
authors.lastname: Makarenko
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA).
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Jacobson
authors.affiliation: Department of Chemistry, University of Houston, 112 Fleming Building, Houston, TX 77204-5003 (USA). miljanic@uh.edu.
authors.forename: Ognjen Š
authors.initials: OŠ
authors.lastname: Miljanić
keywords: adsorption; benzoin condensation; dynamic combinatorial chemistry; macrocycles; shape-persistent macrocycles