Synthesis, crystal structure and optical properties of a naphthylbisimide-Ni complex: a framework on TiO2 for visible light H2 production

Abstract

A novel ligand N,N′-di-(3-(pyridin-2-yl)-1H-pyrazole-5-carbohydrazide) naphthalene 1,4,5,8-tetracarboxylic acid bisimide (PPNB) and its nickel (II) complex (Ni-PPNB) were synthesized and systematically characterized. Both the molecules show higher sensitization activity on the TiO₂ semiconducting system. These composites have interesting photophysical properties as they enable photocatalytic hydrogen production from water with a sacrificial electron donor (SED) using visible light, while neither component alone is able to do so. The photocatalysts have shown long term stability and a maximum turnover number (TON) of 7866 based on Ni-PPNB was obtained after 6 h of irradiation at a catalyst concentration of 2.5 × 10⁻⁵ mol g⁻¹.