Syntheses, crystal structures and third-order nonlinear optical properties of two series of Zn(II) complexes using the thiophene-based terpyridine ligands

• Two series of Zn(II) complexes based on two novel thiophene-based terpyridine ligands have been synthesized.
• The structural features of them were systematic studied.
• Linear absorption and emission spectra in solid state have been systematically investigated.
• All of five complexes exhibited good two-photon absorption within the near-infrared range in solid state.

Two series of Zn(II) complexes, abbreviated as [Zn2·(L1)2·Cl4] (1), [Zn2·(L1)2·Br4] (2), [Zn·(L2)·Cl2]n (3), {[Zn·(L2)·Br2]·(H2O)}n (4) and {[Zn·(L2)·I2]·(H2O)}n (5), were obtained by solvothermal method from ZnX2 (X = Cl, Br, I) and thiophene-based terpyridine ligands. Single-crystal X-ray diffraction analysis showed that complexes 1–2 belong to zero-dimensional structures while complexes 3–5 possess the structures of one-dimensional coordination polymer, and such a difference can be attributed to the different N-position in the terpyridine ligands. In addition to higher thermal stabilities than ligands (up to 400 °C), the titled Zn(II) complexes exhibited strong photoluminescent emissions and good two-photon absorption within the near-infrared range in solid state. And complexes 1–5 showed large two-photon absorption coefficients: 1.404, 1.161, 1.289, 0.965 and 0.473 cm/GW, respectively, which suggested that they have potential applications in the field of two-photon dyes.

Two series of Zn(II) complexes, abbreviated as [Zn2·(L1)2·Cl4] (1), [Zn2·(L1)2·Br4] (2), [Zn·(L2)·Cl2]n (3), {[Zn·(L2)·Br2]·(H2O)}n (4) and {[Zn·(L2)·I2]·(H2O)}n (5), were obtained by solvothermal method from ZnX2 (X = Cl, Br, I) and thiophene-based terpyridine ligands. In addition to higher thermal stabilities (up to 400 °C) than ligands, the titled Zn(II) complexes exhibited strong photoluminescent emissions based on ligands and good two-photon absorption within the near-infrared range in solid state. And complexes 1–5 showed large two-photon absorption coefficients: 1.404, 1.161, 1.289, 0.965 and 0.473 cm/GW, respectively, which suggested that they have potential applications in the field of two-photon dyes.Figure optionsDownload as PowerPoint slide