Vs-cu Metal Clusters In The Synthesis, Characterization And Third-order Nonlinear Optical Properties

The thesis focuses on studies of synthetic reactions and structural characterizations of V-S-Cu clusters. In order to find the better optical functional molecule materials, clusters' thermodynamic stability and third-nonlinear optical (NLO) properties were tested.Fourteen cluster compounds with different structure were synthesized, and two structures of them were determined by Single-crystal X-ray diffraction. They are:[VS₈Cu₆Py₁₂]SCN(1); [V₂S₆O₂Cu₆(3-MePy)₆](2), and the skeleton structure of cluster (1) was synthesized firstly. The structures of other compounds were deduced from the reported homologues by their FT-IR spectra and elemental analyses.The third-nonlinear optical (NLO) properties of cluster (1) were investigated with an 8ns pulsed laser at 532nm. This cluster exhibit very strong third-order NLO absorption effects [α₂= 8.9xl0^-10m/W] and self-focusing performance in 1.46×10^-4mol/dm³ DMF solution. The third-order NLO refractive coefficients (n₂) of cluster (1) are 3.18×10^-18 m²/W, respectively. The corresponding effective NLO susceptibilities x(3) are calculated to be 3.0×10¹¹esu. Based on the NLO experimental results, it can be drawn that the symmetry of skeleton, the number of heavy atoms and the rigidity of structures are the main reasons for the differences in NLO properties.