Design and Synthesis of Imine Carboxylate Functionalized New Transition Metal Based Complexes and Application Studies in Electrocatalytic Reactions

Abstract

newline This thesis contains an in-depth study of different types of electrocatalytic reactions (hydrogen evolution reaction, oxygen evolution reaction, and urea oxidation reaction) with Imine/Carboxylate functionalized transition metal complexes. The synthesized metal complexes were characterized with several characterization techniques (UV, FTIR, PXRD, ICP-MS, SEM, EDS, CHN analysis), including single-crystal x-ray diffraction. Chapter 1 contains a detailed basic introduction to the field of coordination complexes/MOFs/CPs and electrocatalysis. Recent advancement in electrocatalytic field is also included in this chapter. Chapter 2 introduced the design and synthesis of the two unique and symmetrical dinuclear CuII -and MnIII -bifunctional electrocatalysts, which exhibit better HER and OER activity in 0.5 M H2SO4 and 1 M KOH, respectively. Chapter 3 focuses on designing two new mononuclear NiII -embedded coordination complexes and explores them as a bifunctional electrocatalyst for the oxygen evolution and urea oxidation reactions in an alkaline medium. NiII complex was stable up to 100 h in alkaline electrolyte. Chapter 4 focusses the most important work, in which we have designed an unusual defective-dicubane azide bridge tetranuclear NiII 4-Cluster with an imine functionalized ligand, which have highly active and sustainable property for HER in 0.25 M acetate buffer electrolyte by achieving a low overpotential with high double-layer capacitance and low charge-transfer resistance with high Faradaic efficiency (92%). Chapter 5 focuses on a new approach, a parqueted Cu-polymer, which is very much thermodynamically stable up to ~317 and#730;C, and displays a better and sustainable electrocatalytic activity toward HER in 0.25 M acetate buffer electrolytes. Chapter 6 highlighted the two novel Cu2 II and MnIII - coordination salts, which display robust electrocatalysts and remarkable stability for H2 production in a universal pH range (~0-14), highlighting their strong potential for energy conversion applications.