Inorg Chem
Inorganic Materials & Catalysis (IMC) Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India.
Published: September 2023
Metallogels formed from supramolecular interactions of low-molecular-weight gelators (LMWGs) combine the qualities of heterogeneous catalysts and offer the advantages of multifunctionality owing to the facile installation of desired task-specific moieties on the surface and along the channels of the gels. We discuss the applications of a triazole-based Ni(II) gel-derived xerogel () having a high density of Ni(II)-nodes and appended primary amines as a recyclable heterogeneous catalyst for Knoevenagel condensation of aldehyde and malononitrile in water and the solvent-free cycloaddition of CO to form a series of cyclic carbonates with near-quantitative conversion of the respective epoxides, with low catalyst loading (0.59 mol %), high catalyst stability, and recyclability. The structural advantages of , due to the concurrent presence of bifunctional Lewis acid-base sites on the channels, open Ni(II) nodes, N, pendant -NH and its chemical stability, are conducive to the cooperative heterogeneous catalytic activity under mild conditions. This work emphasizes the effective amalgamation of metals with purpose-built ligand systems for the construction of metallogels and their utility as heterogeneous catalysts for desired organic transformations.
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http://dx.doi.org/10.1021/acs.inorgchem.3c01669 | DOI Listing |
ACS Appl Polym Mater
January 2025
Department of Chemistry, Faculty of Science and Engineering, Swansea University, Grove Building, Singleton Park, Swansea SA2 8PP, U.K.
Heterogeneous catalysis is significantly enhanced by the use of highly porous polymers with specific functionalities, such as basic groups, which accelerate reaction rates. Polymers of intrinsic microporosity (PIMs) provide a unique platform for catalytic reactions owing to their high surface areas and customizable pore structures. We herein report a series of Tröger's base polymers (TB-PIMs) with enhanced basicity, achieved through the incorporation of nitrogen-containing groups into their repeat units, such as triazine and triphenylamine.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Organic Chemistry, University of Debrecen Egyetem Square 1 Debrecen 4032 Hungary
Domino Knoevenagel-cyclization reactions of styrene substrates, containing an -(-formyl)aryl subunit, were carried out with -substituted 2-cyanoacetamides to prepare tetrahydro-4-pyrano[3,4-]quinolone and hexahydrobenzo[]phenanthridine derivatives by competing IMHDA and IMSDA cyclization, respectively. The diastereoselective IMHDA step with α,β-unsaturated amide, thioamide, ester and ketone subunits as a heterodiene produced condensed chiral tetrahydropyran or thiopyran derivatives, which in the case of Meldrum's acid were reacted further with amine nucleophiles in a multistep domino sequence. In order to simplify the benzene-condensed tricyclic core of the targets and get access to hexahydro-1-pyrano[3,4-]pyridine derivatives, a truncated substrate was reacted with cyclic and acyclic active methylene reagents in diastereoselective Knoevenagel-IMHDA reactions to prepare novel condensed heterocyclic scaffolds.
View Article and Find Full Text PDFChemSusChem
January 2025
Polish Academy of Sciences, Institute of Organic Chemistry, Kasprzaka 44/52, 01-224, Warsaw, POLAND.
We demonstrate the application of mechanochemistry in the synthesis of indolone-based photoswitches (hemiindigos, hemithioindigos, and oxindoles) via Knoevenagel condensation reactions. Utilizing ball-milling and an organic base (piperidine) acting as catalyst and solvent for liquid assisted grinding (LAG) conditions, we achieve rapid, solvent-free transformations, obtaining a set of known and previously unreported photoswitches, including highly functional amino acid-based photoswitches, multichromophoric derivatives and photoswitchable cavitands based on resorcin[4]arenes. The reaction under mechanochemical conditions gives moderate-to-high yields and is highly stereoselective leading to Z-isomers of hemiindigos and hemithioindigos and E-isomers of oxindoles.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
State Key Laboratory of Applied Organic Chemistry (SKLAOC), Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
Conjugated polymers have attracted extensive attention as semiconducting materials in wearable and flexible electronics. In this study, we utilize atom-economical Knoevenagel reaction to construct two conjugated polymers, PTDPP-CNTT and PFDPP-CNTT, based on dialdehyde-thiophene/furan-flanked diketopyrrolopyrrole (DPP) and 2,2'-(thieno[3,2-b]thiophene-2,5-diyl)diacetonitrile (CNTT). The resulting polymers exhibited suitable highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, small bandgaps, and broad UV-vis-NIR absorptions (≈400-1000 nm), endowing them with photothermal and balanced ambipolar semiconducting properties with hole and electron mobilities over 10 cmVs.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, IIT Dharwad, Dharwad, Karnataka 580007, India.
The favorable redox properties of ferrocene have led to the extensive development of ferrocene-based systems for several electrochemical applications but have scarcely been explored for electrochromism. Here, we report the synthesis and electrochromic properties of novel π-conjugated ferrocene-dicyanovinylene systems (- and -). Monosubstituted (-) and disubstituted (-) compounds have been developed via Knoevenagel condensation of methyl-dicyanovinyl ferrocenes ( or ) with various aromatic aldehydes.
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