Two anionic [Cu6X7]n (X=Br and I) chain-based organic-inorganic hybrid solids with N-substituted benzotriazole ligands

Solvothermal reactions of the flexible ligand 1,6-Bi(benzotriazole)hexane with CuI and KI or CuBr and KBr in ethanol generate two hybrid compounds, namely, {(HETA)[(Cu₆I₇)(ETA)₂]}_n(1) and {K(Cu₆Br₇)(BBTH)}_n(2) (ETA=N-ethylbenzotriazole, HETA=protonated N-ethylbenzotriazole, BBTH=1,6-bi(benzotriazole)hexane). In 1, two [Cu₃I₄] vertex missing cubane-like subunits link each other by sharing one I atom to give a [Cu₆I₇] cluster, which further form novel 1D [Cu₆I₇]_nⁿ⁻ anionic chain. Two in-situ generated ETA ligands finished the 4-coordinated environments of copper centers and another one discrete protonated ETA ligand keeps the charge neutrality for 1. In complex 2, bowl-shaped [Cu₅Br₄] clusters and rhomboid [Cu₂Br₂] dimers link each other to generate a [Cu₆Br₇]_nⁿ⁻ 1D chain. BBTH ligands complete the tetrahedral spheres of Cu(I), and 7-coordinated K atoms further extend the 1D chain motifs to a 2D hybrid layer of 2. The UV-vis diffuse reflectance spectrum and luminescence measurements show that compound 1 and 2 both are potential semiconductor and photoluminescence materials.