Amine-rich Nickel(II)-Xerogel as a Highly Active Bifunctional Metallo-organo Catalyst for Aqueous Knoevenagel Condensation and Solvent-free CO 2 Cycloaddition

作者：Ekata Saha, Hiren Jungi, Shilpa Dabas, Abra Mathew, Rositha Kuniyil, Saravanan Subramanian, Joyee Mitra · 发表于：Inorganic Chemistry · 年份：2023 · DOI：10.1021/acs.inorgchem.3c01669 · 被引用次数：26 · 研究领域：Carbon dioxide utilization in catalysis、Asymmetric Hydrogenation and Catalysis

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 ( NiXero ) 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 2 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 NiXero, due to the concurrent presence of bifunctional Lewis acid–base sites on the channels, open Ni(II) nodes, N triazole, pendant −NH 2 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.