Coordination polymer based on cyano: Synthesis, crystal structure, and fluorescence

One novel 2-D polythreading framework named as Cu₃(CN)₃(NH₃)] (1), was obtained through the self-assembling of CuCN under hydrothermal reaction. It is remarkable that there is a 26-membered Cu₁₀(CN)₈] decanuclear metallamacrocycle with the effective size of ca. 16.8×6.83 Å² along the a-axis. These 2-D layers stack in an ··ABAB···staggered fashion, with the lateral {(CN)Cu₃(NH₃)} moieties of each layer inserting into the voids of the decanuclear metallamacrocycles from two adjacent layers. Optical diffuse reflectance spectrum and the result of DFT calculation reveal that 1 is potential direct semiconducting material. In the solid state at room temperature, 1 shows bright yellow fluorescence under ultraviolet light illumination. Its emissive excited state is primarily attributed to the LMCT, LLCT and ³MMLCT] excited state, based on the result of DFPT calculation.