Work

Facile synthesis of acridine-based nickel(II) complexes via metal-mediated rearrangement of diphenylamine derivative and application in H2 evolution reaction

Year: 2025

Type: article

Abstract: In this study, the formation of acridine-based metal complexes from rearrangement of diphenylamine-2,2′-dicarboxaldehyde (2,2′-dpadc) in the presence of transition metal ions was investigated. As a result, two novel isomorphic nickel(II) complexes bearing acridine-based Schiff-base ligand [NiL ACR ](X) 2 ·CH 3 CN (X = BF 4 ( 1 ), ClO 4 ( 2 ), L ACR = (E)-N 1 -(2-((acridin-4-ylmethylene)amino)ethyl)-N 1 -(2-aminoethyl)ethane-1,2-diamine) were successfully synthesized via a one-pot condensation of 2,2′-dpadc and tris(2-aminoethyl)amine (TREN) with a satisfactory yield of approximately 60%. These complexes were fully characterized by X-ray crystallography, UV-vis spectroscopy and CHN elemental analysis. Additionally, their thermal stability (thermogravimetric analysis) and electrochemical properties were also determined. A plausible mechanism for the nickel(II)-mediated rearrangement of 2,2′-dpadc to form the acridine-based nickel(II) complex was proposed. To demonstrate their potential applications, complex 1 was explored in the realm of electrocatalysis. It exhibited moderate activity towards hydrogen evolution reaction (HER). During 1-h controlled-potential electrolysis (CPE) experiments, H 2 production (16 micromole) was observed with faradaic efficiency of 40% when the reaction was conducted in a TBAPF 6 /DMF solution at -2.1 V vs. Fc/Fc + in the presence of acetic acid as a proton source. The facile synthesis of these acridine-based nickel(II) complexes reported herein may stimulate further development of novel acridine-based ligands and their corresponding metal complexes for a wide range of applications.

Source: Scientific Reports

DOI: 10.1038/s41598-025-00345-3