Synthesis And Quadratic Nonlinear Optical Studies Of Ruthenium Alkynyl Complexes With Oligo(Phenylenevinylene) Bridges

The organometallic materials with D-π-A structure which are synthesized by oligo(p-phenylenevinylene)(OPV) conjugated system have been the lastest process in the quadratic nonlinear optical(NLO) domain. The conjugated system with high π-electronic which is connected between aryl group and alkene units can increase β, reduce the energy of charge transfer between the molecules, and thus improve the nonlinear properties. At present, the research for the OPV chain which have rich delocalized electrons to grow the conjugated system still needs to be studied, especially OPV lengthening. In this thesis, a series of D-π-A compounds were synthesized with Ru metal ligand as electron donor and NO2 as electron acceptor to explore the effect on quadratic nonlinearities and other properities with the OPV lengthening.A series of optimum reaction processes were found through the screening of various reaction conditions, like temperature, catalyst and reactant ratio, and so on. Three raw materials which include phosphate structure were prepared. Then the conjugated chain increased through Horner-Wadsworth-Emmons reaction.The final compounds that included three, five and seven p-phenylenevinylene units were synthesized through the reaction between terminal alkyne compounds and ligated ruthenium complex.The compounds: trans-[Ru{C≡C-1-C6H4-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H4-4-NO2}Cl(dppe)2](32),trans-[Ru{CoC-1-C6H4-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H2-2,5-(n-hexyl)2-4-(E)-CH=CH-1-C6H2-2,5-(n-hexyl)2-4-(E)-CH=CH-1-C6H4-4-NO2}Cl(dppe)2](33) and trans-[Ru{CoC-1-C6H4-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H2-2,5-Et2-4-(E)-CH=CH-1-C6H2-2,5-(n-hexyl)2-4-(E)-CH=CH-1-C6H2-2,5-(n-hexyl)2-4-(E)-CH=CH-1-C6H2-2,5-(2-ethyl-n-hexyl)2-4-(E)-CH=CH-1-C6H2-2,5-(2-ethyl-n-hexyl)2-4-(E)-CH=CH-1-C6H4-4-NO2}Cl(dppe)2](34).All new compounds were characterized by NMR, MS, FT-IR, EA, X-ray and elemental analysis. In particular, the three metal complexes were compared through UV-vis, cyclic voltammetry, spectroelectrochemistry and hyper-Rayleigh scattering(HRS) studies. Density functional theory was applied to the optical results, and low-lying singlet excited-state transitions and orbitals(NTOs) were calculated at the CAM-B3 LYP theory and PBE1 PBE theory. On proceeding from OPV lengthening, all data are consistent with a saturation effect or a turning point. The fully reversible RuII/III oxidation potentials decrease, then keep insignificant and RuIII complexes exhibit low-energy bands at ca. 9000 cm-1. Blue-shifts turned up in the low-energy optical absorption maximum,then caused a red shifts. The quadratic nonlinearity β1064 increases on OPV lengthening, reaching a maximum, then decreasing on further OPV lengthening. The connection between the termini is attenuated and the most intense transition is predominately p?p* in character, not LUMO?HOMO MLCT transition with significant ruthenium involvement in the HOMO and nitro contribution to the LUMO.