Metal-directed supramolecular architectures: From mononuclear to 3D frameworks based on in situ tetrazole ligand synthesis

This work focuses on the investigation of the influence of metal ions and supramolecular interactions on the self-assembly of in situ generated tetrazolate coordination architectures. A series of new metal-organic complexes, [Zn(pzta)(2)(H2O)(2)] (1), [Cu(pzta)(2)](H2O)(3) (2), [Cd(pzta)(2)](n) (3), [Ag(pzta)](n) (4), and [Cd-2(pzta)(OH)(SO4)](n) (5) [pzta = pyrazinyl tetrazolate], have been achieved by the in situ hydrothermal reactions of pyrazinecarbonitrile, sodium azide, and different metal ions. Complexes I and 2 have similar mononuclear structures bearing distinct intermolecular hydrogen-bond interactions to form two different 3D supramolecular networks based on 4(4)-subnets. Complex 3 features a ID crossed-shape chain structure. Complex 4 is a coordination polymer comprised of mildly undulated 2D layers with a (4.8(2)) topological network. Complex 5 is a 3D diamondoid framework constructed by pentanuclear cadmium cluster nodes and pzta linkers. The configurations of complexes 1-5 span from mononuclear (1, 2), to one-dimensional (3) and two-dimensional (4), to three-dimensional (5), which indicates that metal ions play an essential role in the framework formation of the in situ generated tetrazolate architectures. Furthermore, complexes 1, 3, and 5 exhibit strong blue photoluminescence in similar energy regions.