Syntheses, structures and luminescence of a series of coordination polymers constructed with 4-substituted 1,2,4-triazole and biscarboxylate co-ligands

Abstract

Eight coordination polymers {[Cd₃(btpm)₂(1,4-bdc)₃]·6H₂O}_n (1), {[Cd₂(btpm)(mip)₂(H₂O)]·1.25H₂O}_n (2), {[Cd₂(btpm)(nip)₂(H₂O)]·H₂O}_n (3), {[Cd₄(btpm)₃(H_0.5suc)₂(suc)₂Cl(H₂O)₂]·9H₂O}_n (4), {[Cd₂(btpm)(glu)₂(H₂O)₂]·5H₂O}_n (5), {[Cd₂(btpm)(mbda)₂(H₂O)]·3H₂O}_n (6), {[Zn(btpm)(1,4-bdc)](1,4-H₂bdc)}_n (7), {[Zn(btpm)(adc)]·3H₂O}_n (8) (btpm = bis(4-(1,2,4-triazol-4-yl)phenyl)methane, 1,4-bdc = 1,4-benzenedicarboxylate, mip = 5-methyl-isophthalate, nip = 5-nitro-isophthalate, suc = succinate, glu = glutarate, mbda = 1,3-benzenediacetate, adc = 1,3-adamantanedicarboxylate) were hydrothermally synthesized. 1 shows an unusual 8-connected three-dimensional network based on Cd₃(COO)₂ trimer clusters. 2 exhibits an unusual (3,7)-connected three-dimensional network based on Cd₂(COO) dimers. 3 presents a (3,4,5)-connected 3D network. 4 shows the 6-connected three-dimensional pcu net based on Cd₄Cl tetranuclear clusters. 5 exhibits a 2-fold interpenetrating three-dimensional pcu network based on Cd₂(COO)₂ dimers. 6 presents an unusual 2D network based on nanotube-like [Cd₂(mbda)₂] chains. 7 shows the intriguing 2D → 3D polythreaded network based on a special 2D (6,3) network, with six Zn(II) atoms at six corners and four 1,4-bdc and two double btpm at six edges. 8 exhibits an undulated 2D (4,4) network. 1–8 show structural diversity based on mono-metal, bi-, tri- and tetra-nuclear metal clusters. The coordination polymers can be tuned with different biscarboxylates and metal cations based on the semi-rigid 4-substituted 1,2,4-triazole ligand btpm. The luminescence and thermal stability were investigated.