Temperature tuned synthesis of zinc N,N-bis-(1(2)H-tetrazol-5-yl)-aniine complexes:: from Zn3O cluster-based 3-connected 63-hcb and (3,6)-connected (43)2(46)-kgd layers to Zn5(OH)4 chain-based 3D open framework

Hydrothermal in situ [2 + 3] cycloaddition reaction of dicyanamide and azide in the presence of Zn(II) ions at 120, 150, and 180 degrees C generated [Zn4O(Hbta)(3)(H2O)(6)] 1, [Zn-7(OH)(2)(Hbta)(6)(H2O)(6)] 2, and [Zn-5(OH)(4)(bta)(2)]center dot 2H(2)O 3 (H(3)bta = N,N-bis(1(2)H-tetrazol-5-yl)-amine), respectively. 1crystallizes in hexagonal space group P62c and shows a layered structure with 3-connected 6(3)-hcb topology in which Zn3O clusters and unsaturated three-coordinate Zn(II) ions function as 3-connected nodes; 2crystallizes in trigonal space group P3cl and also shows a layered structure with (3,6)-connected (4(3))(2)(4(6))-kgd topology in which Zn3O clusters and six-coordinated Zn(II) sites function as 3-connected nodes as 6-connected nodes, respectively; 3 is a 3D organic-inorganic hybrid open framework constructed by Zn-5(OH)(4) chains. The triply deprotonated bta(3-) anion is first observed in 3, and rare three-coordinate Zn(II) ions are revealed in 1. Analysis of relationship between structure and synthesis condition reveals that 1 is a metastable kinetic phase whose structure is closely related to that of 2. Both 1 and 2 are constructed by Zn3O(Hbta)(3) units and discrete Zn ions. The coordination mode of doubly deprotonated Hbta in 1 and 2 are also same. This study reveals that a higher reaction temperature is helpful to remove amine-hydrogen of H(3)bta to form triply deprotonated bta anion. The emergence of triply deprotonated bta species may explain why structure of 3 is significantly different from those of 1 and 2. Compounds 1-3 show strong blue-green emission, assigned as ligand-centered pi ->pi* excitation.