Tuning zinc(ii) coordination polymers based on bis(1,2,4-triazol-1-yl)ethane and 5-substituted 1,3-benzenedicarboxylates: syntheses, structures and properties

Abstract

In our effect to tune the structures of Zn(II) coordination polymers, six zinc(II) coordination polymers {[Zn(bte)(1,3-bdc)]·0.5H₂O}_n (1), {[Zn(bte)(NO₂-1,3-bdc)]·3H₂O}_n (2), {[Zn(bte)(I-1,3-bdc)(H₂O)]·H₂O}_n (3), {[Zn(bte)₂(H₂O)₂](SO₃-1,3-Hbdc)·4H₂O}_n (4), {[Zn(bte)(Hbtc)]·3H₂O}_n (5) and {[Zn₃(bte)₂(btc)₂(H₂O)₂]·2.5H₂O}_n (6) (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane, 1,3-bdc = 1,3-benzenedicarboxylate, NO₂-bdc = 5-nitroisophthalate, I-1,3-bdc = 5-iodoisophthalate, SO₃-1,3-bdc = 5-sulfoisophthalate, btc = 1,3,5-benzenetricarboxylate) have been synthesized and structurally characterized. 1, 2 and 3 are independent 1D MONTs. An interesting structural feature of 3 is that the I groups of each 1D MONT polythread into two adjacent 1D MONTs to form a (1D → 2D) polythreaded array and a 3D supramolecular architecture. 4 shows the double chain cation [Zn(bte)₂(H₂O)₂]_n²ⁿ⁺ and 3D hydrogen bond architecture. 5 exhibits a 2D (4,4) network and a 3D hydrogen bond architecture. In 6, each btc ligand bridges three Zn(II) atoms (one Zn1 and two Zn2) and forms a 3-connected 2D network [Zn₃(btc)₂(H₂O)₂]_n. Each bte ligand connects two [Zn₃(btc)₂(H₂O)₂]_n 2D networks to construct a (3,4)-connected 3D network with point symbol (6²·14⁴)(14³)₄. Such a (3,4)-connected 3D network is unprecedented, as to the best of our knowledge. The luminescence and thermal stability of 1–6 were investigated.