- Cadmium Metal-Organic Frameworks Based on Ditopic Triazamacrocyclic Linkers: Unusual Structural Features and Selective CO2 Capture
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Two three-dimensional cadmium metal-organic frameworks with general formula [Cd2(L1)(H2O)3](NO3)0.7(HCOO)0.2Br0.1 (Cd2L1, L1 = 1,4,7-tris(4-carboxybenzyl)-1,4,7-triazacyclononane) and Cd(HL2)(H2O)2 (CdL2, L2 = 1,4,7-tris(3-(4-benzoate)prop-2-yn-1-yl)-1,4,7-triazacyclononane) based on 1,4,7-triazacyclononane N-functionalized by different arylcarboxylic acids were prepared under solvothermal conditions and characterized by single crystal X-ray analysis and porosity measurements. The crystal structure of Cd2L1 reveals a cationic net with a bcs topology, and nodes are constituted by dinuclear cadmium complexes, in which each cadmium atom adopts a hexacoordinated environment involving both the carboxylate and the cyclic amine. In contrast, CdL2 displays a 2-fold interpenetrated structure with a pcu topology. In this net, the node is a mononuclear complex in which the Cd atom exhibits a seven-coordination geometry. Both materials show a high permanent porosity and good CO2 adsorption properties with a high selectivity over N2 and CH4. The adsorption capacity and selectivity for CO2 were calculated from a multisite Langmuir isotherm model and the ideal adsorbed solution theory, which gave insights into the nature of solid-gas interactions and showed the influence of interpenetration or polarity of the charged framework on their adsorption properties.
- Feuchter, Hervé,Ortiz, Guillaume,Rousselin, Yoann,Bessmertnykh-Lemeune, Alla,Brandès, Stéphane
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- Regioselective Iron-Catalysed Cross-Coupling Reaction of Aryl Propargylic Bromides and Aryl Grignard Reagents
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An iron-catalysed Kumada-type cross-coupling reaction between aryl substituted propargylic bromides and arylmagnesium reagents has been developed. Propargylic coupling products were the main or only outcome, and propargyl/allene regioselectivity was shown to depend on the electronic nature of the substituents on the triple bond of the substrate and on the arylmagnesium halide. Best selectivities were observed when electron donating substituents were present in either reagent. The process is stereoespecific, occurs with configuration inversion and no carbon-based radicals seem to be involved in the mechanism. (Figure presented.).
- Manjón-Mata, Inés,Quirós, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
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p. 146 - 151
(2019/12/11)
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- Iron-Catalyzed Coupling of Propargyl Bromides and Alkyl Grignard Reagents
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An iron-catalyzed Kumada-type cross-coupling reaction of propargyl halides with alkylmagnesium reagents is described. The reaction is fast, takes place in smooth conditions, tolerates several functional groups that would be able to react with the Grignard reagent, and may afford either allene or propargyl coupling derivatives. Factors involved in the observed regioselectivity have been studied.
- Domingo-Legarda, Pablo,Soler-Yanes, Rita,Quirós-López, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
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p. 4900 - 4904
(2018/09/10)
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