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 [Cd2(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 1 and 2
have similar mononuclear structures bearing distinct intermolecular hydrogen-bond interactions to form two different 3D supramolecular
networks based on 44-subnets. Complex 3 features a 1D crossed-shape chain structure. Complex 4 is a coordination polymer comprised
of mildly undulated 2D layers with a (4.82) 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.