Catalytic, Luminescence Activities and Structure of Metal-Organic Frameworks Containing CuCN Building Blocks and Bipodal Bridging Ligands

Abstract

The reactions of K3[Cu(CN)4], R3SnCl and bipodal ligands, where R = (n-Bu)3SnCl and L = quinoxaline (qox) and R = Me3SnCl and L = quinazoline (qaz) afford the red needle crystals of \( {}_{\infty }^{3} \left[ {{\text{Cu}}_{2} \left( {\text{CN}} \right)_{2} \mu {\text{-(qox)}}} \right]_{2} \), 1 and the orange needle crystals of [Cu2(CN)2μ(qaz)]n, 2. 1 was subjected to single crystals X-ray study while 2 was investigated by IR, 1H NMR and mass spectra as well as TGA. The crystal structure of 1 exhibits puckered CuCN chains connected by qox molecules forming 2D-sheets. The 2D-sheets contain hexagonal nets stacked in A···A···A fashion. The paralleled sheets are close packed via extensive H-bonds, π–π stacking, strong Cu-Cu interaction and short Cu–C contacts which develop 3D-network. Unique rhombic [Cu2(μ3-CN)2] motifs result as consequence of interwoven of the 2D-sheets. The structure of 2 exhibits different XRPD pattern than that of 1 although, the two structures have the same Cu:CN:L stoichiometric ratio. The emission spectra of 1 and 2 display bands around 390, 420 and 475 nm corresponding to MC transition, 1(n,π*) → So and MLCT, respectively. Thus, 1 and 2 can be considered as examples of room-temperature luminescent Cu-containing polymers which can be used in applications as molecular sensing systems. Also, the oxidative degradation of Metanil Yellow (MY) dye has been investigated by hydrogen peroxide catalyzed by 1 or 2. The catalytic activity of 1 is more pronounced than that of 2.