Synthesis, crystal structures, and two-photon absorption properties of dithiocarbazate Zn(II) and Pd(II) complexes

A curcumin-based TPA four-branched copper(II) complex probe for in vivo early tumor detection

A multibranched Cu(II) complex CuL2 curcumin-based was synthesized and characterized by single-crystal X-ray diffraction analysis. The photophysical properties of the complex have been investigated both experimentally and theoretically. The results show that the target complex exhibits higher quantum yield and larger two-photon absorption (TPA) cross-section in the near infrared (NIR) region compared with its free ligand. The cell imaging studies in vitro and in vivo reveal that the complex shows good photostability and excellent tumor targeting capability to tested cancerous cells, which can be potentially used for early tumor detection.

Crystal structures, spectra properties and DFT calculations studies on 4-phenyl-1-(3-phenylallylidene)thiosemicarbazide and its Ni(II) complex

4-Phenyl-1-(3-phenylallylidene)thiosemicarbazide (HL) and its metal complex of NiL2 have been synthesized. For them, elemental analysis, IR and X-ray single crystal diffraction have been carried out. In complex NiL2, the central Ni(2+) ion coordinates with two deprotonated ligands of L(-) and adopts a distorted square planar configuration with the Ni(2+) ion being located at the inversion center. The thermal analyses result shows that complex NiL2 undergoes two decomposition processes. For the title compounds, DFT calculations of the structures and natural population analysis (NPA) have been performed at B3LYP/LANL2DZ level of theory. The predicted geometric parameters are compared with the experimental values and they are supported each other. By using TD-DFT method, electron spectra of ligand HL and complex NiL2 have been predicted, which suggest the B3LYP/LANL2DZ method can approximately simulate the electron spectra for the system presented here. The NPA results indicate that, for ligand HL, the electronic absorption spectra are mainly assigned to n-π(∗) and π-π(∗) electron transitions, while for the complex NiL2, the electronic transitions are mainly derived from the contribution of an intra-ligand (IL) transition, a metal-to-ligand charge transfer (MLCT) transition and a d-d transition. Based on vibrational analysis, thermodynamic properties for ligand HL and complex NiL2 at different temperatures have been obtained.