RESUMO
A regiodivergent allylation of 1H-indoles highly selectively at the C3 and N1 positions with ß-acyl allylic sulfides through desulfurative C-C/C-N bond-forming reactions has been developed under mild conditions. Notably, the remarkable site-selective switch can be achieved by a delicate choice of solvents and bases. This cost-efficient method displays a broad substrate scope, good functional compatibility, and excellent site-selectivity, thus offering a divergent synthesis of indole substituted α-branched enones, which possess diverse potential opportunities for further applications and derivatization.
RESUMO
In the title compound, {(C4H12N)[Mn(HCO2)3]} n , the Mn(II) atom lies on an inversion centre and is coordinated by O-atom donors from the three double-bridging formate ligands, one of which lies across a crystallographic mirror plane, giving a slightly distorted octahedral coordination sphere. A three-dimensional NaCl-type framework is generated in which the tetra-methyl-ammonium cations, which lie across mirror planes and occupy the cavities in the polymer structure, form weak C-Hâ¯O hydrogen bonds with the formate ligands.
RESUMO
Carbon dioxide capture and conversion have attracted extreme enthusiasm from the scientific community owing to global warming and environmental problems. However, conversion of CO2 under atmospheric pressure is of great challenge because of the inertness of CO2. Herein, we present a novel covalent triazine framework (CTF-DCE) prepared via ZnCl2-catalyzed ionothermal trimerization reaction of di(4-cyanophenyl)ethyne, which displays a high Brunauer-Emmett-Teller surface area of 1355 m2 g-1 and an excellent CO2 capture capacity of 191 mg/g at 273 K/1 bar. More importantly, silver species can be successfully fixed on the CTF matrix to produce a stable CTF-DCE-Ag heterogeneous catalyst for outstanding catalysis in the terminal alkyne carboxylation reactions under atmospheric pressure. CTF-DCE-Ag exhibited over sixfold higher turnover numbers than Ag@MIL-101. The recyclability test of the CTF-DCE-Ag catalyst demonstrated a great potential application in various environmental and energy-related applications.
RESUMO
A multifunctional carbazolic porous framework (Cz-TPM), with a tetrahedral core, has been synthesized by FeCl3 oxidative coupling polymerization. The Brunauer-Emmett-Teller surface area of the obtained polymers reaches 713.2 m2 g-1. Gas adsorption isotherms show that Cz-TPM exhibits large carbon dioxide (97.9 mg g-1, 9.8 wt %, 273 K, and 1 bar) and hydrogen uptake capacities (149.3 cm3 g-1, 1.34 wt %, 77 K, and 1 bar). Furthermore, Cz-TPM has been found to display tandem visual detection of iodide and mercury, respectively. The Cz-TPM dispersion turns to yellow in the presence of iodide salts and subsequently changes to nearly colorless on addition of Hg2+ salts that could be easily observed by the naked eye. Cz-TPM can detect I- via "turn off" fluorescence quenching, and then the in situ generated Cz-TPM@I complexes can recognize Hg2+ ions via "turn on" fluorescence recovery. More importantly, Cz-TPM is stable over common solvents and can be easily recovered by excessive water washing and centrifugation for further repeated use. As far as we know, carbazolic porous organic frameworks enabling detection of I- and Hg2+ have not been reported.
RESUMO
A new heptazine-based polymer network (Cy-pip) with highly rich nitrogen sites has been synthesized via catalyst-free direct coupling of cyameluric chloride (Cy) and piperazine (Pip). Cy-pip exhibits large CO2 uptake capacity (103.4 mg/g, 9.4 wt %, 1 bar/273 K) with high selectivity (117) toward CO2 over N2. Furthermore, this framework with high Lewis basic nitrogen sites has also been exploited as heterogeneous catalyst for Knoevenagel reaction of aromatic and heterocyclic aldehydes with active methylene compounds. Moreover, the catalyst can recycle up to four times with only a minor loss of activity.
RESUMO
The reversible crystal transformation between the mononuclear complex [Cu(tzbc)2(H2O)4] (1) and the 4-fold interpenetrated diamondoid MOF [Cu(tzbc)2] (2) was chemically implemented and structurally interpreted. Interestingly, despite 4-fold interpenetration, desolvated with 1D channels and rich N-groups shows exclusive CO2 adsorption of up to 12.5 wt% at room temperature and low pressure, indicating potential application in the separation of industrial and automobile exhaust.
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An expanded pyridyl-decorated MOF-505 analogue[Cu2(L)(H2O)2]·G(x) (H4L = 5,5'-(pyridine-2,5-diyl)diisophthalic acid, G = solvent molecule) has been solvothermally synthesized and reported. It exhibited rare hierarchical meso- and microporosity. With exposed unsaturated Cu(II) sites and Lewis basic pyridyl sites, the material shows both large CO2-uptake capacity (123.4 cm(3) g(-1) at 273 K, 1 bar) and high selectivity for CO2 over N2 (55.7) at 273 K. Furthermore, for the first time the compound has been exploited for its heterogeneous catalytic performance toward the cyanosilylation reaction under solvent-free conditions. The compound can be recycled up to five times with only a minor loss of activity.
Assuntos
Dióxido de Carbono/isolamento & purificação , Cobre/química , Compostos Organometálicos/química , Ácidos Ftálicos/química , Piridinas/química , Adsorção , Catálise , Modelos Moleculares , PorosidadeRESUMO
A new interpenetrated bioactive nonlinear optical metal-organic framework [Zn2(ppa)2(1,3-bdc)(H2O)] has been designed and synthesized, which shows both a high drug content of 63.9% and a good slow release effect in simulated physical conditions compared to other non-interpenetrated bioactive MOFs. It also shows a large powder second-harmonic generation (SHG) efficiency of 5.6 times that of KH2PO4 (particle size: 150-200 µm).