Syntheses, structures and photocatalytic properties of a series of cobalt coordination polymers based on flexible bis(triazole) and dicarboxylate ligands

Abstract

Seven cobalt(II) coordination polymers [Co(obtz)(Meip)]n (1), [Co(obtz)(ip)]n (2), {[Co2(obtz)2(tdc)2(H2O)]·2H2O}n (3), [Co(obtz)(1,4-bdc)(H2O)]n (4), [Co(obtz)(adc)]n (5), {[Co(obtz)2(fum)]·2H2O}n (6) and [Co(obtz)(hip)]n (7) (obtz=1,2-bis(1,2,4-triazole-1-ylmethyl)benzene, Meip=5-methylisophthalate, ip=isophthalate, tdc=2.5-thiophenedicarboxylate, 1,4-bdc=1,4-benzenedicarboxylate, adc=1,3-adamantanedicarboxylate, fum=fumarate, hip=5-hydroxyisophthalate) were synthesized. 1 shows a (3,4)-connected 2D network with the point symbol of (3·82)(32·4·82·9). 2 exhibits a (3,5)-connected 2D network with the point symbol of (42·6)(42·66·82). 3 presents a (3,6)-connected 2D network with the point symbol of (3·4·6)(32·44·54·63·7·8). 4 and 5 exhibit unusual 2D→2D polycatenated network based on 2D sql network. 6 shows a 2D sql network. 7 presents the ladder-like 1D chain with side arms. The diverse structures demonstrate that the structures of coordination polymers can be tuned by the dicarboxylate and bis(triazole) co-ligands. The thermal stability of 1–7 was investigated. 1–7 are effective photocatalytic catalysts for the degradation of methyl orange.