Structure modulation in zinc–ditetrazolate coordination polymers by in situ ligand synthesis

Abstract

Three new Zn^II–ditetrazolate coordination polymers (CPs), namely [Zn(m-pdtz)(4,4′-bipy)(H₂O)]_n (1), [Zn₂Cl₂(m-pdtz)(4,4′-bipy)]_n (2) and [Zn₂(OH)₂(m-pdtz)]_n (3) (4,4′-bipy = 4,4′-bipyridine, m-H₂pdtz = 5,5′-1,3-phenylene-ditetrazole), have been constructed by an in situ ditetrazolate-ligand synthesis system. The formation of m-pdtz^2- ligand involves the Sharpless [2 + 3] cycloaddition reaction between isophthalonitrile (IPN) and NaN₃ in the presence of Zn²⁺ ions as Lewis-acid catalysts under hydro/solvothermal conditions. Single-crystal structural analyses reveal that compound 1 exhibits a new 6-connected 3D structural topology constructed from dimeric {Zn₂} clusters as secondary building units (SBUs), compound 2 represents a 2D sql structural feature built from rhombic tetrameric {Zn₄} rings as SBUs, while compound 3 displays a new (4,6)-connected 3D structural topology constructed from rod-shaped 1D Zn-chains as SBUs. Regarding these three CPs, we have performed a thorough investigation on their crystal structure, topology, and fluorescence property.