Synthesis and Characterization of a New Zinc‐Coordinated Covalent Organic Polymer: A Versatile Catalyst for the Synthesis of 2‐Substituted Benzimidazoles and Quinoline Derivatives

ABSTRACT

A Zn(II)‐coordinated covalent organic polymer (Zn‐COP) was synthesized from TMPT‐CHO and 2,6‐DAAQ, wherein Zn(II) ions are accommodated within the cavities of the polymeric framework. The structural integrity and morphology of Zn‐COP were systematically characterized by ¹³ C CP/MAS solid‐state NMR, FT‐IR, XRD, XPS, SEM, TEM, EDX, elemental mapping, TGA, BET, CHN, and ICP–OES analyses, confirming the successful construction of the COP framework and incorporation of Zn(II) species. The catalytic performance of Zn‐COP was evaluated in the one‐pot synthesis of three classes of N ‐containing heterocycles, namely 2‐substituted benzimidazoles, 2‐aminoquinolines, and 2‐phenylquinolines, from readily accessible substrates under solvent‐free conditions. The optimized protocol afforded excellent product selectivity together with high conversions and product yields. Furthermore, the catalytic process exhibited favorable green chemistry parameters, including AE, E‐factor, CE, PMI, and RME. The catalyst could be readily separated from the reaction mixture and reused for four consecutive cycles with negligible loss of activity, demonstrating the potential of Zn‐COP as a robust and sustainable heterogeneous catalytic system.