Synthesis,Optical And Electronic Properties And Second Order Hyperpolarizabilities Of Azo-Functionalized Ruthenium Alkynyl Complexes

The materials with nonlinear optical（NLO） properties are creating intense interest because oftheir enormous applications in emerging optoelectronic and photonic technologies such as optical storage, optical limiting, liquid crystal displays and thin film transistors. Researchers have begun to focus on developing and studying nonlinear optical materials with better performance.The organometallic complexes which combines with the advantages of organics and inorganics have been attracted a lot of attention due to their potential NLO properties. At the same time, aromatic azo derivatives which have –N=N– group have not yet received much attention. In this thesis I synthesize a series of azo-conjugated organometallic compounds and research their second-order NLO properties. Specific content as follows.（1） Aromatic azo compound 2c（4-BrC₆H₄N=N-4-C₆H₄C≡CSiPr₃ⁱ） was prepared by means of Mills reaction from the starting materials 4-bromoaniline and 4-iodoaniline. Then by means of successive Sonogashira coupling/deprotection reactions compound b1（4-O₂NC₆H₄C≡C-4-C₆H₄-N=N-4-C₆H₄C≡CSiPr₃ⁱ） was prepared in good yield. Reaction of b1 with [RuCl₂（dppm）₂] or [RuCl（dppe）₂]（PF6） followed by treatment with NEt3 afforded compound Ru1（trans-[Ru{4,4’,4’’-C≡C-C₆H₄-N=NC₆H₄-C≡C-C₆H₄NO₂}Cl（dppm）₂]） and Ru₂（trans-[Ru{4,4’,4’’-C≡C-C₆H₄N=N C₆H₄C≡CC₆H₄-NO₂}Cl（dppe）₂]）. Another azo compound 2f（4-NCC₆H₄N=N-4-C₆H₄C≡CSiPr₃ⁱ） was prepared using the same way as compound 2c. Azo compound 2i（4-O₂NC₆H₄N=N-2,6-Et2-C₆H₂-NH2） was readily obtained by means of a standard diazotization coupling reaction of 4-nitroanilines and 2,6-diethylanilines. Compound 2f and 2i was treated with DIBAL in dry toluene for two hours, and by means of Horner–Wadsworth–Emmons C=C bond formation reaction b2（（E）-4-O₂NC₆H₄C=C-4-C₆H₄N=N-4-C₆H₄C≡CSiPr₃ⁱ） and b3（（E）-4-O₂NC₆H₄N=N-2,6-Et2C₆H₂-1-C=C-4-C₆H₄C≡CH） were prepared. Reaction of b2 or b3 with [RuCl（dppe）₂]（PF6） followed by treatment with NEt3 afforded compound Ru3（trans-[Ru{（E）-4,4’,4’’-C≡CC₆H₄N=NC₆H₄C=CC₆H₄ NO₂}Cl（dppe）₂]） and Ru4（trans-[Ru{（E）-4,4’,4’’-C≡CC₆H₄N=NC₆H₂（2,6-Et2）C=CC₆H₄NO₂}Cl-（dppe）₂]）. All of the compounds were characterized using IR, proton, carbon and phosphorus NMR spectroscopy, EI and high-resolution mass spectrometry, and elemental analysis.（2） Some complexes were analysed using UV-Vis spectroscopy, cyclic voltammetry（CV） and Hyper-Rayleigh scattering（HRS）. Results were rationalized using DFT calculations, and we analyse the influence of different π conjugate chain structure on the second-order NLO properties.