214622-81-8Relevant articles and documents
Ligand Rigidification for Enhancing the Stability of Metal-Organic Frameworks
Lv, Xiu-Liang,Yuan, Shuai,Xie, Lin-Hua,Darke, Hannah F.,Chen, Ya,He, Tao,Dong, Chen,Wang, Bin,Zhang, Yong-Zheng,Li, Jian-Rong,Zhou, Hong-Cai
supporting information, p. 10283 - 10293 (2019/07/04)
Metal-organic frameworks (MOFs) have been developing at an unexpected rate over the last two decades. However, the unsatisfactory chemical stability of most MOFs hinders some of the fundamental studies in this field and the implementation of these materials for practical applications. The stability in a MOF framework is mostly believed to rely upon the robustness of the M-L (M = metal ion, L = ligand) coordination bonds. However, the role of organic linkers as agents of stability to the framework, particularly the linker rigidity/flexibility, has been mostly overlooked. In this work, we demonstrate that a ligand-rigidification strategy can enhance the stability of MOFs. Three series of ligand rotamers with the same connectivity but different flexibility were prepared. Thirteen Zr-based MOFs were constructed with the Zr6O4(OH4)(-CO2)n units (n = 8 or 12) and corresponding ligands. These MOFs allow us to evaluate the influence of ligand rigidity, connectivities, and structure on the stability of the resulting materials. It was found that the rigidity of the ligands in the framework strongly contributes to the stability of corresponding MOFs. Furthermore, water adsorption was performed on some chemically stable MOFs, showing excellent performance. It is expected that more MOFs with excellent stability could be designed and constructed by utilizing this strategy, ultimately promoting the development of MOFs with higher stability for synthetic chemistry and practical applications.
Synthesis of 2-and 2,7-functionalized pyrene derivatives: An application of selective C-H borylation
Crawford, Andrew G.,Liu, Zhiqiang,Mkhalid, Ibraheem A. I.,Thibault, Marie-Helene,Schwarz, Nicolle,Alcaraz, Gilles,Steffen, Andreas,Collings, Jonathan C.,Batsanov, Andrei S.,Howard, Judith A. K.,Marder, Todd B.
scheme or table, p. 5022 - 5035 (2012/05/20)
An efficient synthetic route to 2-and 2,7-substituted pyrenes is described. The regiospecific direct C-H borylation of pyrene with an iridium-based catalyst, prepared in situ by the reaction of [{Ir(μ-OMe)cod}2] (cod=1,5-cyclooctadiene) with 4,4′-di-tert-butyl-2,2′-bipyridine, gives 2,7-bis(Bpin)pyrene (1) and 2-(Bpin)pyrene (2, pin=OCMe 2CMe2O). From 1, by simple derivatization strategies, we synthesized 2,7-bis(R)-pyrenes with R=BF3K (3), Br (4), OH (5), B(OH)2 (6), and OTf (7). Using these nominally nucleophilic and electrophilic derivatives as coupling partners in Suzuki-Miyaura, Sonogashira, and Buchwald-Hartwig cross-coupling reactions, we obtained 2,7-bis(R)-pyrenes with R=(4-CO2C8H17)C6H4 (8), Ph (9), Ca≡CPh (10), Ca≡C[{4-B(Mes)2}C 6H4] (11), Ca≡CTMS (12), Ca≡C[(4-NMe 2)C6H4] (14), Ca≡CH (15), N(Ph)[(4-OMe)C6H4] (16), and R=OTf, R′=Ca≡CTMS (13). Lithiation of 4, followed by reaction with CO2, yielded pyrene-2,7-dicarboxylic acid (17), whilst borylation of 2-tBu-pyrene gave 2-tBu-7-Bpin-pyrene (18) selectively. By similar routes (including Negishi cross-coupling reactions), monosubstituted 2-R-pyrenes with R=BF3K (19), Br (20), OH (21), B(OH)2 (22), [4-B(Mes)2]C 6H4 (23), B(Mes)2 (24), OTf (25), Ca≡CPh (26), Ca≡CTMS (27), (4-CO2Me)C6H4 (28), Ca≡CH (29), C3H6CO2Me (30), OC 3H6CO2Me (31), C3H 6CO2H (32), OC3H6CO2H (33), and O(CH2)12Br (34) were obtained from 2. These derivatives are of synthetic and photophysical interest because they contain donor, acceptor, and conjugated substituents. The crystal structures of compounds 4, 5, 7, 12, 18, 19, 21, 23, 26, and 28-31 have also been obtained from single-crystal X-ray diffraction data, revealing a diversity of packing modes, which are described in the Supporting Information. A detailed discussion of the structures of 1 and 2, their polymorphs, solvates, and co-crystals is reported separately. Copyright
