20260-22-4Relevant articles and documents
Palladium-benzimidazolium salt catalyst systems for Suzuki coupling: development of a practical and highly active palladium catalyst system for coupling of aromatic halides with arylboronic acids
Huang, Wen,Guo, Jianping,Xiao, Yuanjing,Zhu, Miaofen,Zou, Gang,Tang, Jie
, p. 9783 - 9790 (2005)
Palladium-benzimidazolium salt catalyst systems have been studied for the Suzuki coupling. A different substitutent effect has been uncovered with respect to nitrogen substituents in the benzimidazolium salts from the palladium-imidazolium salt analogs. A practical and highly active palladium catalyst system, PdCl2/N,N′-dibenzylbenzimidazolium chloride 2, has been identified for the Suzuki coupling of aromatic halides with arylboronic acids. The coupling of a wide array of aromatic halides with arylboronic acids with the PdCl2-2 catalyst system gave good to excellent yields. The effective palladium loading could be as low as 0.0001 mol% and 0.01-0.1 mol% for iodide and bromide substrates, respectively. The coupling of unactivated aromatic chlorides with arylboronic acids also gave good results using Cs2CO3 as base with a 2 mol% palladium loading. The electronic factors from aromatic halides exert a significant influence on the Suzuki coupling catalyzed by the PdCl2-2 system while the electronic effect from the arylboronic counterparts is negligible. The aromatic halides with modest steric hindrance could also couple smoothly with phenylboronic acids using the PdCl2-2 catalyst system.
Planarity of terphenyl rings possessing: O -carborane cages: Turning on intramolecular-charge-transfer-based emission
So, Hyunhee,Kim, Jea Ho,Lee, Ji Hye,Hwang, Hyonseok,An, Duk Keun,Lee, Kang Mun
supporting information, p. 14518 - 14521 (2019/12/09)
To clarify the relationship between planarity and intramolecular charge transfer (ICT), two o-carboranyl compounds (TCB and FCB) containing different ortho-type terphenyl rings, namely, perfectly distorted or planar phenyl rings, were synthesised and fully characterised. Although the emission spectra of both compounds presented intriguing dual-emission patterns in solution at 298 or 77 K and in the film state, distorted TCB mostly showed locally excited emission, whereas planar FCB demonstrated intense emission corresponding to an ICT transition. Interestingly, the emission efficiencies and radiative decay constants of terphenyl-based o-carboranyl compounds were gradually enhanced by increasing the planarity of the terphenyl groups. These results verify the existence of a strong relationship between the planarity of appended aryl groups and ICT-based radiative decay in o-carborane-substituted compounds.
Activation-Dependent Breathing in a Flexible Metal–Organic Framework and the Effects of Repeated Sorption/Desorption Cycling
Engel, Emile R.,Jouaiti, Abdelaziz,Bezuidenhout, Charl X.,Hosseini, Mir Wais,Barbour, Leonard J.
supporting information, p. 8874 - 8878 (2017/07/17)
A non-interpenetrated metal–organic framework with a paddle-wheel secondary building unit has been activated by direct thermal evacuation, guest exchange with a volatile solvent, and supercritical CO2 drying. Conventional thermal activation yields a mixture of crystalline phases and some amorphous content. Exchange with a volatile solvent prior to vacuum activation produces a pure breathing phase with high sorption capacity, selectivity for CO2 over N2 and CH4, and substantial hysteresis. Supercritical drying can be used to access a guest-free open phase. Pressure-resolved differential scanning calorimetry was used to confirm and investigate a systematic loss of sorption capacity by the breathing phase as a function of successive cycles of sorption and desorption. A corresponding loss of sample integrity was not detectable by powder X-ray diffraction analysis. This may be an important factor to consider in cases where flexible MOFs are earmarked for industrial applications.
