Assembly of four d10-metal inorganic–organic hybrid coordination polymers based on bipyrazine imine-based ligand: Synthesis, crystal structures and luminescent properties

Abstract

Four new inorganic–organic hybrid coordination polymers {[Ag₂L(NO₃)₂]·H₂O}_n (1), [Ag₂L(SCN)₂]_n (2), [CdL(SCN)₂]_n (3), and [CdLI₂]_n (4) have been synthesized and structurally characterized by IR spectroscopy, thermogravimetric (TG) analyses and complete single crystal structure analyses, where L is 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene. The structure of polymer 1 is a 3D coordination framework containing Ag-(μ-NO₃⁻) inorganic bridging units, in which each L coordinates four silver atoms through two pyrazinylimine chelate units and two terminal monodentate pyrazinyl N donors. Polymer 2 displays a new 3D inorganic–organic hybrid network through the coordination interactions between Ag-(1,1,3-μ-SCN⁻) inorganic 2D sheets and bidentate bridging ligands with two terminal monodentate pyrazinyl N donors. Bidentate bridging ligands link 1D inorganic chains Cd-(1,3-μ-SCN⁻) system for 3 and Cd-(μ-I⁻) system for 4 to form a similar two-dimensional layer network. The luminescent properties of polymers 1–4 were investigated in the solid state at room temperature.