Five tetrazolate-based coordination polymers with cationic copper(I) halide motifs, namely, Cu 4 (tta) 2 Cl 2 (1, tta = tetrazolate), Cu 4 (tta) 2 Br 2 (2), Cu 2 (tta)I (3), Cu 3 (mtta) 2 Cl (4, mtta = 5methyltetrazolate), and Cu 2 (tta)Br (5) were prepared by hydro(solvo)thermal reactions of CuX 2 or CuX with tetrazolato ligands in the presence of HX. Compounds 1, 2, and 3 show eight-connected square-planar layered structures constructed with butterfly-like [Cu 4 X 2 ] 2+ (X = Cl, Br, I) clusters and μ 4 -tta groups. Isomorphs 1 and 2 crystallize in the orthorhombic space group Pbca, but 3 crystallizes in the orthorhombic space group Pbam, because each μ 4 -tta group is co-According to a recent review by Li, [11] there are several routes towards copper(I) halide aggregates, for example direct introduction and in situ generation of a cuprous source. It seems that reduction of cupric salts is the most promising route for the in situ generation of a cuprous source. [12] An excess of halide ions and a higher pH value are favorable for the promotion of the formation of CuX aggregates. [13] Hereby, haloid acids are introduced into the reactions of tetrazole and CuX 2 (X = Cl, Br) with the hope of obtaining new copper(I) halide architectures, and five unusual cationic copper(I) halide based coordination polymers, Cu 4 (tta) 2 Cl 2 (1, tta = tetrazolate), Cu 4 (tta) 2 Br 2 (2), Cu 2 (tta)I (3), Cu 3 (mtta) 2 Cl (4, mtta = 5-methyltetrazolate), and Cu 2 (tta)Br (5) were synthesized (Scheme 2). Interestingly, our experiments reveal that the amount of hydrogen halide has a great influence on the structures of final products. Compounds 1, 2, and 3 show eight-connected squareplanar layered structures constructed from butterfly-like [Cu 4 X 2 ] 2+ clusters and μ 4 -tta groups, which represent the only 2D coordination polymers with eight-connected square-planar topology to date. Compound 4 is a [Cu 3 Cl] 2+ cluster based on a ten-connected ZrIn 2 topological framework, but 5 is a pillar layered structure constructed from [Cu 2 Br] n n+ cationic layers. The tetrazole groups of 4 come from in situ [2+3] cycloaddition reactions of acetonitrile with sodium azide. Compounds 1, 2, 4, and 5 exhibit strong green-blue emission in the solid state at room temperature, whereas cuprous iodide complex 3 shows red luminescence. Scheme 2. Self-assembly reactions of coordination polymers 1-6; R = H or CH 3 .
Results and Discussion
Synthesis ChemistryThe reaction of CuCl 2 or CuBr 2 and tetrazole under hydro(solvo)thermal conditions with HX (X = Cl, Br, F) as Eur.