Synthesis, Characterization And Second-order Nonlinear Optical Property Studies Of Zn(Ⅱ)–ethylene-diamine Complexes

Seven novel ethylene-diamine(en) complexes,(en H2)Cl2(1), Zn Cl4×2Cl×2(en H2)(2), Zn Br Cl2I·(en H2)(3), Zn Cl3(en H)(4), Zn(en)3·2Br·H2O(5), Zn Br(C9H11N2O)(6), Zn(C16H14N2O2)×H2O(7), have been successfully synthesized under the proper p H values, respectively, which based on the reaction of flexible ethylene-diamine and halogenated zinc. In addition, the title compounds 1–7 have been characterized by the elemental analyses, infrared spectra, X-ray structures and so on. The crystal structures analyses show that the complexes 3–4 have asymmetric structures with chiral space group. With the construction of hydrogen bond interaction, the supramolecular structures are formed, respectively, 3D network of 1-5, 2D ribbon structure of 6, and 1D parallel chain of 7. The Hirshfeld surfaces analyses show that the various weak forces among the molecules, which are crucial in building supramolecular architectures. The solid photoluminescence studies display that complexes 2-7 have blue fluorescence in the region of 420–470 nm, especially, the complexes 6-7 with strong fluorescence. The second-order nonlinear optical property studies show that the chiral complex 4 display good SHG efficiency, which is almost 0.5 times that of KDP, and the another chiral complex 3 has shown none SHG signal. The thermal stable studies show that complexes 2-7 are thermal stable with the completely decomposed temperature 600 °C.