Three 3D Co() cluster-based MOFs constructed from polycarboxylate acids and bis(imidazole) ligands and their derivatives: magnetic properties and catalytic performance for the ORR

• Published in: Dalton transactions : an international journal of inorganic chemistry 2019-09, Vol.48 (35), p.13369-13377
• Main Authors: Yang, Ming-Xing, Chen, Li-Juan, Ma, Rong, Cai, Jian-Nan, Shi, Yuan-De, Lin, Shen
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Benzene; Carbon; Carbonization; Catalysis; Clusters; Cobalt; Coordination compounds; Crystallography; Dicarboxylic acids; Displays; Imidazole; Ligands; Magnetic properties; Metal-organic frameworks; Organic chemistry; Porous materials
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c9dt02278c

Three 3D polymeric complexes containing polynuclear Co( ii ) units, [Co 3 (bpda) 3 (bib) 2 ]·H 2 O ( 1 ), [Co 5 (OH) 2 (H 2 O) 2 (bpda) 4 (bib) 2 ]·2H 2 O ( 2 ), and [Co 2 (OH)(bib)(bpt)]·H 2 O ( 3 ) (H 2 bpda = biphenyl-2,4′-dicarboxylic acid, H 3 bpt = biphenyl-3,4′,5-tricarboxylic acid, bib = 1,4-bis(1-imidazolyl)benzene), have been prepared by urothermal synthesis. Complex 1 exhibits an unusual (4,6)-connected 3D network based on binuclear Co( ii ) clusters and Co 2+ centers bridged by bpda 2− and bib ligands. Complex 2 , containing a novel pentanuclear Co( ii ) cluster, features a porous 3D MOF with a regular nanosized tunnel. Complex 3 contains an interesting tetranuclear Co( ii ) cluster and displays an amazing 3D porous MOF built from double-layered 2D [Co 2 (μ 3 -OH)(bpt) 3 ] n networks pillared by two rows of bib spacers. In the title complexes, polycarboxylate acids serve to construct and stabilize the polynuclear Co( ii ) clusters, while bis(imidazole)s help to expand the dimensionality of MOFs. Complexes 2 and 3 show antiferromagnetic properties. Compound 3 with high surface area, high yield, high purity, and high chemical stability was used as a precursor to fabricate Co,N-codoped porous carbon materials by simple carbonization under an Ar atmosphere. The catalytic properties of the Co,N-codoped porous carbon material derived from complex 3 (denoted as CoNC-3) as an ORR electrocatalyst were studied. CoNC-3 displays superior electrocatalytic performances for the ORR. Three 3D Co-MOFs constructed from polycarboxylate acids and bis(imidazole) ligands were prepared by urothermal synthesis and the derived porous carbon material shows comparable electrocatalytic property toward the ORR.