Four Co(II) coordination polymers based on 4,4′-bis(benzimidazol-1-ylmethyl)biphenyl and aromatic carboxylic acids co-ligands: Synthesis, structures, and photocatalytic properties

Abstract

Four Co(II) coordination polymers, [Co(L)2(1,4-bdc)]n (1), [Co0.5(HL)(Hbtc)]n (2), {[Co(L)(1,3-bdc)(H2O)]·1.5H2O}n (3) and {[Co2(L)2(nip)2]·2H2O}n (4) (L=4,4′-bis(benzimidazol-1-ylmethyl)biphenyl, 1,4-H2bdc=1,4-benzenedicarboxylic acid, H3btc=1,3,5-benzenetricarboxylic acid, 1,3-H2bdc=1,3-benzenedicarboxylic acid, H2nip=5-nitroisophthalic acid) have been synthesized under hydrothermal reaction conditions. Both complexes 1 and 2 feature chain structures, and 2 is ultimately extended into a 2D supramolecular framework via classic hydrogen bonding interactions. Complex 3 possesses a (4,4) grid with {44.62} topology. Complex 4 displays a 2D (6,3) layer, which is further extended into a 3D supramolecular network with unusual binodal (3,4)-connected sqc1425 topology via O–H⋯O hydrogen bonding interactions. Additionally, the thermal stability, UV/Vis diffuse-reflection spectra and photocatalytic behaviors of these CPs have also been investigated.