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To mimic superoxide dismutase, two new copper(II) complexes, [Cu(bqad)X2] (1, X = Cl; 2, X = Br; where bqad = N,N′-bis(2-quinolinylmethyl)amantadine), have been synthesized and characterized by elemental analysis, electronic absorption, IR and single crystal X-ray diffraction. The copper ions in 1 and 2 have a penta-coordination geometry, composed of three nitrogen atoms from one bqad ligand and two halide anions. The complexes showed quasi-reversible one-electron Cu(II)/Cu(I) redox waves, as determined by cyclic voltammetry. By using an NBT assay at pH 7.8, the superoxide dismutase (SOD)-like activity (IC50) of 1 and 2 were measured to be 0.43 and 0.32 μM, respectively. The enhancement in the SOD-like activity of 2 can be ascribed to the formation of the species [Cu(bqad)2(H2O)2]2+ in aqueous solution due to the two labile bromine ions. Furthermore, DFT calculations were performed in order to understand the relationship between the structures and activities of the mimics.

To mimic the active site of Cu,Zn-SOD, new copper(II) complexes (1, [Cu2(HL)2(L)2](ClO4)2; 2, [Cu(HL)2(phen)](ClO4)2; where HL = (N-methyl-2-methylol)imidazole, phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. Copper(II) in 1 is four-coordinate by a N2O2 plane with two copper(II) ions bridged with two oxygens from the deprotonated hydroxylmethyl pendants. Each Cu2+ in 2 is coordinated by four nitrogens from two HL and one co-ligand of 1,10-phenanthroline. Electrochemistry of the complexes was studied by cyclic voltammetry. The atomic net charges distribution and frontier molecular orbital energies were obtained by Gaussian 98 program with DFT method at B3LYP/lanl2dz level. The SOD-like activity (IC50) of 1 and 2 were measured as 0.10 ± 0.01 and 0.19 ± 0.01 μM by NBT assay at pH 7.8. The higher SOD activity of 1 could be attributed to the coordination configuration and the labile hydroxymethyl pendants.

The dinuclear complex [Cu2(HL)2(H2O)2](ClO4)2 (1) [H2L = 5′-(pyridin-2-yl)-1-H,2′-H-3, 3′-bis(1, 2,4-triazole)] was obtained and fully characterized. It exhibits a centrosymmetry configuration, in which each copper(II) ion is pentacoordinate with four nitrogen atoms of two triazole ligands and one oxygen atom from a water molecule. The net atomic charges distribution and atomic orbital contribution to frontier molecular orbitals were obtained using the Gaussian 98 program with Hartree-Fock method at LANL2DZ level, indicating that the copper(II) ion has the potential to accept the electron of O2·–. The complex showed quasi-reversible one-electron CuII/CuI redox waves with redox potentials of –0.034 V. The SOD-like activity (IC50) of 1 was measured to be 0.18 ± 0.01 μM by xanthine/xanthine oxidase-NBT assay at pH 7.8. The relatively high SOD activity suggests that the positive charge of protonated triazole can effectively steer O2·– to and from the active copper ion.

We show that Cu ions doped in (${\mathrm{K}}_{\mathit{x}}$${\mathrm{Na}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${)}_{0.4}$(${\mathrm{Sr}}_{\mathit{y}}$${\mathrm{Ba}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${)}_{0.8}$${\mathrm{Nb}}_{2}$${\mathrm{O}}_{6}$ (KNSBN) form two energy levels in the band gap, which increase the effective charge-combination-center concentration ${\mathit{N}}_{\mathrm{eff}}$. The two-wave coupling gain and the response speed of KNSBN crystals are increased while the photoconductivity and the effects of a dc field on the photorefractive properties are reduced. Self-pumped phase conjugation (SPPC) experiments have revealed that the effects of Cu ions on the photorefractive properties have a wavelength dependence. The SPPC response time at the ${\mathit{e}}^{\mathrm{\ensuremath{-}}1}$ level can be shortened to 200 ms.

The optical quality Pb1-xBaxNb2O6 single crystals have been grown by Czochraski method from the melt. Their structure, dielectric, ferroelectric properties were studied. Transmission spectra, two-wave mixing properties were measured. This crystal will be an available material for photorefractive applications.

Self-pumped phase conjugation has been observed in Ce-doped (K0.5Nb0.5)2y (Sr0.61Ba0.39)1-yNb2O6 (KNSBN) crystal at 633nm by using He-Ne laser. The phase conjugate reflectivity as high as 40% was measured. The reflectivity as function of incident angles and the relation of response time to the incident intensities were studied experimentally.

A reflectivity of 45% of the self-pumped phase-conjugate wave in (K0.5-Na0.5)0.2(Sr0.75Ba0.25)0.9Nb2O6:Cu crystal at the environmental temperature T ~ 70°C has been obtained. The temperature effect in this kind of self-pumped phase-conjugator is studied.

The image intensity inversion operation was succeeded by using the new type KNSBN:Cu crystal self-pumped phase-conjugate mirror. The new phase-conjugator was demonstrated to have the reguired specifications for this optical processing application.

The Cu-doped KNSBN crystals have been grown. The self-pumped phase conjugate mirrors of Cu-doped KNSBN crystals have been demonstrated. The phase conjugate reflectivity reaches as high as 68% for the crystal with 0.04 wt.% Cu-doped. The phase conjugate reflectivity and its response time were also measured as a function of the argon-ion laser wavelengths.

Self-pumped phase conjugate in trapezoid-cut Co-doped (KNa)0.1 (Sr0.75Ba0.25)0.9Nb2O6 (Co-KNSBN) crystal was demonstrated without external reflection mirrors and applied field, phase conjugation reflectivities as high as 40.5% were measured. The threshold power was lower than 0.02 W/cm2. The device was operated in one-region four-wave mixing using the photorefractive effect.

The mechanism for the high-performance KNSBN:Cu crystal self-pumped phase-conjugator is first put forward in this letter as no-loop photorefractive self-bending succesive four-wave mixing interaction. And the photorefractive backscattering amplification was found to play a very important role in it.

Observation of the dynamics in a single-mode Ar+ composite resonator laser using KNSBN:Cu crystal self-pumped phase-conjugator is reported. The sequence of instabilities occurring on gain change corresponds to the transition to chaos of the logistic equation. Period-doubling route to chaos, and period-5, -3, -3×2 and -2 together with -3 windows in the chaotic range were observed. The strange attractor which is similar to that of the forced Duffing equation is obtained by reconstructing phase-space pictures of the system.

Edge enhancement has been performed in Ce-doped (K0.5Na0.5)2y (Sr0.61Ba0.39)1-yNb2O6 (KNSBN) crystal at 633 nm with low incident-light intensities (10-3 W/cm2). We calculated the expected images which show good agreement with the images that we have experimentally observed.

Growth and photorefractive properties of KNSBN:Co crystal are reported for the the first time.Crystals were grown by CZ technique and the growth habits of them are severly affected by the amount of Co ions.New energy levels are formed in the energy band gap. Comparing to undoped KNSBN, KNSBN:Co has larger two-wave coupling coefficient, shorter response time and larger photo-induced free electron concentration in the experiment of two-wave coupling. Phase conjugation reflectivity of 56% and response time of 150ms were determined in the experiment of degenerate four-wave mixing.

Four faces of TGS crystal were chosen to study the growth kinetics. BCF spiral growth mechanism for the surface diffusion model was analyzed using the kinetic data of the four faces. We found it is more important that the growth units enter the surface layer to grow after overcoming the dehydration activation energy, than the process of surface diffusion. Two simple crystal forms of TGS spontaneousnucleation crystals were also observed.