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Triple and Quadruple Triptycene Gears in Rigid Macrocyclic Frameworks
Author(s) -
Toyota Shinji,
Kawahata Kenta,
Sugahara Kota,
Wakamatsu Kan,
Iwanaga Tetsuo
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201701067
Subject(s) - triptycene , trimer , chemistry , sonogashira coupling , tetramer , phenylene , rotation (mathematics) , coupling (piping) , crystallography , computational chemistry , stereochemistry , dimer , polymer chemistry , palladium , organic chemistry , geometry , polymer , materials science , mathematics , enzyme , catalysis , metallurgy
The structures and dynamic behavior of macrocyclic compounds consisting of three or four 9,10‐triptycyl units and 1,2‐phenylene and ethynylene frameworks were studied as multiple‐gear systems. These compounds were synthesized from 9,10‐diethynyltriptycene derivatives and a diiodobenzene by repeated Sonogashira coupling reactions. DFT calculations revealed that the benzene rings in the triptycene units meshed with each other in the inside region, which led to overall attractive interactions through π ··· π and CH ··· π contacts, regardless of the significant molecular deformations in the trimer. The symmetric 1 H NMR signal pattern implied that the rotation of the gear moieties takes place rapidly, even at a low temperature. We analyzed the rotational mechanisms of the dynamic behavior by DFT calculations, for which the rotation was partly or fully correlated. The estimated rotational barriers were very low at 22.5 and 3.9 kJ mol –1 for the trimer and tetramer, respectively.