ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis and green catalysis of a Chitosan-supported N,N′-pyridyl imine nickel (II) diacetate complex

Jay Prakash Gupta, Kunj Bihari Paliwal, Deepshikha Soni, Girdhar Pal Singh, and Narendra Singh Chundawat

Department of Chemistry, Bhupal Nobles’ University, Udaipur, India

E-mail: chundawat7@yahoo.co.in

Received: 10 October 2025  Accepted: 11 February 2026

Abstract:

In this study, a novel and efficient strategy for the functionalization of chitosan is proposed through its reaction with 2-acetylpyridine, resulting in the formation of a Chitosan-supported N,N′-pyridyl imine (CPI) intermediate in the initial step. Subsequently, the CPI ligand undergoes coordination with nickel (II) acetate [Ni (OAc)₂] to form a chitosan-supported N,N′-pyridyl imine nickel (II) diacetate complex (CPINi). The synthesized CPINi complex was extensively characterized using a comprehensive set of analytical techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field-emission scanning electron microscopy (FESEM), FESEM elemental mapping, Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS), Brunauer–Emmett–Teller (BET) surface area analysis, Atomic absorption spectroscopy (AAS), Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES), Leaching test (WLP & TCLP), Thermogravimetric–differential thermal analysis (TG–DTA) and differential scanning calorimetry (DSC). Catalytic evaluation revealed that CPINi complex exhibits significant catalytic activity in several important organic transformations, including Suzuki–Miyaura cross-coupling, Wacker oxidation, Buchwald–Hartwig amination and Michael addition reactions. Furthermore, CPINi complex demonstrated excellent efficiency in the catalytic reduction of the toxic pollutant nitrobenzene to the comparatively less harmful aniline. Overall, these findings establish CPINi complex as a cost-effective, environmentally benign and multifunctional catalytic material with considerable potential for applications in green chemistry and sustainable organic synthesis.

Graphical abstract

Keywords: Chitosan-supported N,N′-pyridyl imine nickel (II) diacetate complex; Catalyst; Nickel acetate; Suzuki–Miyaura cross-coupling; Buchwald–Hartwig amination

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04739-z

Chemical Papers 80 (6) 5941–5961 (2026)