A Binuclear Cadmium(II) Cluster Based on π•••π Stacking and Halogen•••Halogen Interactions: Synthesis, Crystal Analysis and Fluorescent Properties

An interseting binuclear complex [Cd-2(tcpa)(4)(bipy)(2)] (1) has been hydrothermally synthesized with 3, 5, 6-trichloropyridine phenoxy acetatic acid (Htcpa) and 2, 2 '-bipyridine (bipy) coligands. The X-ray single-crystal diffraction analysis shows that the Cd-II center is situated on unusual triangular prismatic geometry formed by two pyridyl nitrogen atoms of a bipy molecule and four carboxyl oxygen atoms of four different tcpa(-) ligands. The four tcpa(-) anions play as bis-monodentate linkers and connect two Cd-II ions together to form the dimer structure of 1. 1 is further assembled into a 2D layer by the co-effects of pi center dot center dot center dot pi stacking and Cl center dot center dot center dot Cl halogen bonds interactions. Moreover, 1 exhibits intense solid-state luminescence emissions centered at 442 nm at room temperature, which mainly originates from the intraligand pi -> pi* transitions of tcpa(-). The CCDC number of 1 is 1,935,091.