32917-57-0Relevant articles and documents
Effects of main chain and acceptor content on phase behaviors of hydrogen-bonded main-chain/side-chain combined liquid crystalline polymers
Yang, Shuai-Qi,Qu, Wei,Pan, Hong-Bing,Zhang, Yu-Dong,Zheng, Shi-Jun,Fan, Xing-He,Shen, Zhihao
, p. 355 - 364 (2016/01/26)
Main-chain/side-chain combined liquid crystalline polymers (MCSCLCPs) are usually difficult to synthesize and their degrees of polymerization are relatively low, which bring difficulties in studying their structure-property relationships. In order to solve this problem, we prepared a new series of MCSCLCPs containing mesogen-jacketed liquid crystalline polymer (MJLCP) main chains via hydrogen-bonding (H-B). A pyridine derivative with a triphenylene (Tp) unit is the H-B acceptor. In addition to the temperature dependence, the phase behavior of the resulting complex is strongly influenced by the content of the H-B acceptor and the rigidity of the side-chain core of the MJLCP. The resulting complexes exhibit different phase structures: (1) a columnar nematic phase or a smectic A (SmA) phase formed by the supramolecular MJLCP chain as a whole; (2) hierarchical nanostructures including a hexagonal columnar phase or a SmA phase of the whole polymer chain plus a discotic nematic phase associated with the Tp moieties.
Copper-catalyzed recycling of halogen activating groups via 1,3-halogen migration
Grigg, R. David,Van Hoveln, Ryan,Schomaker, Jennifer M.
supporting information, p. 16131 - 16134,4 (2020/09/09)
A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp2 to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o-halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp3 C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.