Solvothermal synthesis and structural characterization of new Zn - Triazole - Sulfoisophthalate frameworks

Two new Zn-based coordination polymers based polymers, namely. Zn ₇(TRZ)₈(SIP)₂·7H₂O (1) and Zn₅Na₂(DMA)₄-(TRZ)₄(SIP) ₄·5H₂O (2) (TRZ = 1,2,4-triazole, SIP = sulfoisophthalate, and DMA = dimethylamine). were synthesized under mild solvothermal conditions. Their crystal structures were characterized by single-crystal X-ray diffraction, and their thermal properties were examined by thermogravimetric analysis. Structure 1 crystallizes in monoclinic P2 ₁/n space group (a = 14.050(3) Å, b = 12.517(3) Å, c = 15.377(3) Å, β= 97.95(3)^o, V = 2678.3(9) ų, Z = 2), while structure 2 is described as triclinic P1̄ (a = 9.701(2) Å, b= 12.442(3) Å, c= 17.218(3) Å, α = 89.83(3)^o, β= 75.01(3)^o, V = 73.33(3) ^o, V = 1917.5(7) A^o3. Z = 1). Structure 1 contains 8- and 16-membered channels made of Zn polyhedra linked by TRZ, which are occupied by water molecules and SIP ligands. Structure 2 consists of one-dimensional chains of Zn-TRZ moieties that are linked to each other via SIP. It is a negatively charged open framework in which Na⁺ ions and protonated dimethylamine in the cavities serve as counterions.