Nickel(II) cluster-based mixed-cation coordination polymer synthesized from 2-mercaptobenzoic acid and its application

Abstract

High‐nuclearity metal clusters have received considerable attention not only because of their diverse architectures and topologies, but also because of their potential applications as functional materials in many fields. To explore new types of clusters and their potential applications, a new nickel(II) cluster‐based mixed‐cation coordination polymer, namely poly[hexakis[μ4‐(2‐carboxylatophenyl)sulfanido]di‐μ3‐chlorido‐tri‐μ2‐hydroxido‐octanickel(II)sodium(I)], [Ni8NaCl2(OH)3(C7H4O2S)6]n, 1, was synthesized using nickel chloride hexahydrate and mercaptobenzoic acid (H2mba) as starting reactants under hydrothermal conditions. The material was characterized by single‐crystal X‐ray diffraction (SCXRD), Fourier transform IR spectroscopy, thermogravimetric analysis, powder X‐ray diffraction and X‐ray photoelectron spectroscopy analysis. SCXRD shows that 1 consists of a hexanuclear nickel(II) [Ni6] cluster, dinuclear NiII nodes and a mononuclear NaI node, resulting in the formation of a complex covalent three‐dimensional network. In addition, a tightly packed NiO/C&S nanocomposite is fabricated by sintering the coordination precursor at 400 °C. The uniform nanocomposite consists of NiO nanoparticles, incompletely carbonized carbon and incompletely vulcanized sulfur. When used as a supercapacitor electrode, the synthesized composite shows an extra‐long cycling stability (>5000 cycles) during the charge/discharge process.

Nickel(II) Cluster-Based Pillar-Layered Metal–Organic Frameworks for High-Performance Supercapacitors

“…44 was used as a precursor for carbonization to produce carboncontaining nickel oxide electrode materials with high performance. 45 Unlike the conductive MOFs, H 2 mba does not have a large heterocyclic macroconjugated structure and is a poor conductor. However, it is a common inexpensive raw material with several benefits, including strong structural rigidity with several coordination sites and small conjugated structures, such as a benzene ring and a carboxyl group.…”

“…For this study, 2-mercaptobenzoic acid (H 2 mba) was used as a ligand for coordination with nickel in the presence of sodium hydroxide to obtain the pillar-layered MOF [Ni 8 (mba) 6 (Cl) 2 Na­(OH – ) 3 ] n (Ni-mba-Na) . Ni-mba-Na was used as a precursor for carbonization to produce carbon-containing nickel oxide electrode materials with high performance . Unlike the conductive MOFs, H 2 mba does not have a large heterocyclic macroconjugated structure and is a poor conductor.…”