Caimao Zhan

Influence of the molecular configuration on second-order nonlinear optical properties of coordination compounds

Abstract The relationships between structure and nonlinear optical (NLO) properties of coordination compounds in terms of influence of molecular configuration on linear and NLO properties are reviewed. The molecular configurations involved are square pyramidal, tetrahedral, square planar, octahedral, sandwich and linear. Based on the experimental results, empirical rules of these relationships have been proposed, which may help the design of new NLO materials from organometallic and coordination compounds.

Synthesis and structural characterization of novel multifunctional polysiloxanes having photo-refractive properties

A novel series of multifunctional polysiloxanes with photo-refractive properties have been synthesized via a hydrosilylation reaction with 9-allylcarbazole (ACZ) as charge-transporting agent, 1-allyloxyl-2,5-dimethyl-4-(4-nitro-phenylazo)benzene (ADNPAB) as electro-optical chromophore and poly(hydrogenmethylsiloxane). The component concentrations in the polymers can be controlled by different reagent ratios between ACZ and ADNPAB. The structural characterization of the polymers is presented, together with 1 H NMR, IR spectra and elemental analysis.

Synthesis, photoconduction and electro-optical effect of a polysilane with disperse red-1 as side chain*

Abstract The structure of polymethylphenylsilane (PMPS) was modified by chloromethylation and then condensation with sodium salt of Disperse Red-1 (DR-1). The product (PMPS-DR1) shows a broad absorption in the wavelength of 400–700nm, and exhibits glass transition at ca. 155°C. Photoconductivity of a 2μm thick film made of PMPS-DR1 was measured to be in the range of 10 −18 ~10 −11 Scm −1 , and electric field dependent. After electrical poling, the film shows electro-optical effect with r 33 = O. 8pm/V.

Synthesis and structural characterization of multifunctional polysiloxanes for photorefractive effect

We have synthesized a novel kind of multifunctional polysiloxanes containing charge-transporting agent and electro-optical chromophobe as side chains for photorefractive application. The structural characterization of this kind of polymer is presented by 1H-NMR, IR spectra and elemental analysis.

Bismaleimide resins modified by bi- or tri-allyl-functionalized azo chromophores for second-order optical nonlinearity

Several novel azo dye chromophores with allyl groups at one or two ends of the molecules were synthesized. Differential scanning calorimetry and thermogravimetric analysis tracing showed that these chromophores can be thermally cured with bismaleimidodiphenyl methane to afford a series of crosslinked, and chromophore-modified bismaleimide resins without any appreciable decomposition up to >300°C, while IR spectra analysis indicated that it is not a trivial task to achieve highly-crosslinked BMI resins due to decomposition of the azo dye chromophores. The effects of different chromophores on the curing conditions and thermal stability of these modified BMI resins are discussed. It is noticeable that incorporating a chromophore into the network of BMI resins by its reactive groups at both ends facilitates improvement of the thermal stability of the materials.

Synthesis of polysiloxanes exhibiting both photoconductive and electro-optical properties

Abstract We have synthesized a novel kind of multifunctional polysiloxane containing charge-transporting agents and electro-optical chromophores as side chains for photorefractive application. The chemical structural characterization of this kind of polymer is presented by 1 H-NMR, IR spectra and elemental analysis.

Determination of the first molecular hyperpolarizability, β, of some organomercury compounds by solvatochromism

Abstract Twelve arylmercuric nitrophenylacetylides, (where DI, Br, Cl, MeO, EtO, Me, H2N, MeHN, Me2N or O2N; R1H or Me; R2H or Me), have been synthesised, and their β, the first molecular hyperpolarizability, have been examined by solvatochromism to be in the order of 10−29 esu while the λmax in the electronic spectra are around 310nm. These linear organomercury molecules may represent a new approach to solve the conflict between increasing nonlinearity and improving transparency.

Synthesis and characterisation of polyaniline catalysed and doped by squaric acid

Aniline was polymerized in dilute aqueous squaric acid and the polyaniline (PAn) was doped with 10−1–10−3 mol/L of squaric acid. The corresponding electrical conductivity of the PAn is 10−1–10−2 S ⊙ cm−1. The solubility of the doped PAn has been improved in common polar organic solvents. The FTIR and UV—Vis spectra show that the PAn has the structure of both quinone and imine.

Synthesis of several novel multifunctionalized chromophores for second-order NLO

4-[4-disubstituted-amino-phenylazo]-(alpha) - cyanocinnamates with two or more functional groups (such as hydroxyl, allyl) at both ends of the molecule to be used as novel chromophores for second-order NLO polymeric materials are synthesized by diazonium coupling and Knoevenagel condensation. In this two-step method, the tediousness of functionalization at the electron-acceptor end is avoided by selecting (alpha) -cyanoacrylate as electron-acceptor. The products are easy to purify, and the whole procedure is simple and time-saving, which facilitates the choice of polymer system for effective hardened NLO lattice in a broader range.

Synthesis and SHG effect of some cyclotriphosphazene derivatives

Twenty derivatives of hexachlorocyclotriphosphazene were synthesized by substituted reaction. The structure of the cyclotriphosphazenes were identified by i.r. uv-vis, n.m.r. and elemental analysis, proving that they are fully substituted cyclotriphosphazenes. Kurtz powder determination of SHG showed that two of them displayed SHG effect. X-ray diffraction determination of N3P3(OC6H4F)6 is presented to explain SHG effect.