K.Z. Wang

Electronic memory switching in a new charge transfer-complex thin film

Charge transfer-complex thin films of 1,4-bis(2,2-dicyanovinyl)benzene(BDCB) with silver, sandwiched between two silver elctrodes, show current-controlled bistable electronic switching and memory behavior. The switching from a high to low impedance is believed to be associated with chemical phase change similar to that for charge transfer-complex thin films of TCNQ with either copper or silver. The films are analyzed by infrared, ultraviolet-visible spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction.

Synthesis, characterization, crystal structure and luminescent property studies on a novel heteronuclear lanthanide complex {H[EuLa2(DPA)5·8H2O]·8H2O}n (H2DPA = pyridine-2,6-dicar☐ylic acid)

Abstract The title complex was synthesized and its crystal structure determined by X-ray diffraction. Both europium and lanthanum are nine-coordinated, their coordination polyhedra being distorted tricapped trigonal prisms. The europium is located on a two-fold crystallographic axis. The title complex is connected to an infinite polymer via the bridging of the ligands. The IR and luminescent spectra of the complex were studied.

Langmuir-Blodgett film study on N-hexadecyl pyridinium tetrakis (2-naphthyltrifluoroacetone) europium, HDP.Eu(NTA)4

Abstract The amphiphilic strong luminescence europium complex given in the title has been synthesized. Three isotherms at different temperatures were measured and the 15°C one has two different solid phases, indicating two kinds of molecular arrangements on the water surface. The monolayer was transferred on different hydrophilic pretreated plates using LB technique for different purposes. The LB films were characterized by IR, UV-vis and luminescence spectra.

Electrical switching and memory phenomena in the Ag-BDCP thin film

Abstract A novel organic materials 2,6-bis(2,2-bicyanovinyl)pyridine (BDCP) and its complex function thin films of Ag-BDCP were synthesized in our laboratory. Stable and reproducible electric bistable properties were observed in the Ag-BDCP thin films. The thin films were analyzed by high-resolution scanning electron microscopy, X-ray diffraction, ultraviolet-visible absorption and infrared transmission spectroscopy.

Synthesis, characterization and crystal structure of Me2NC6ChCHC5H4N(C2H5)+[La(TTA)4]−(TTA α-thenoyltrifluoroacetonato)

Abstract The complex ( E )- N -ethyl-4-(2-(4′-dimethylaminophenyl)ethnyl)pyridinium tetrakis( α -thenoyltrifluoracetanoto)lantanum(III) was synthesized, and its crystal structure was determined by single-crystal X-ray crystallography and refined to the final R of 0.046 and R w of 0.052. IR, electronic absorption spectroscopy (UV-vis) and thermogravimetric and differential thermal analysis (TG-DTA) for the complex are also resported.

Optical and electrical properties of the langmuir-blodgett films prepared from a rare earth coordination compound

Abstract The stable floating Langmuir film of N-hexadecylpyridinium tetrakis-(1-phenyl-3-methyl-4-benzoyl-pyrazolone-5-one) europium formed at air-water interface, could be deposited at a surface pressure of 10 mN/m onto various hydrophilic substrates of fuzed quartz, single crystal calcium floride and transparent indium tin oxide (ITO) glass successively with a transfer ratio of around unity. LB films with more than 50 layers in Z or Y type were obtained. The films were characterized by ultraviolet, fluorescent, X-ray photoelectron spectroscopy and low angle X-ray diffraction. The electric conductivity of the film is reported as well.

Liquid-crystalline behaviors of lanthanide complexes containing hemicyanine

The liquid crystalline behaviors of four lanthanide complexes, (E)-N-hexadecyl-4-(2-(4-(dimethylamino)phenyl)ethylene)pyridinium tetrakis(1-phenyl-3-methyl-4-benzoyl-5-pyrazolonato)lanthanide(La, Nd, Dy and Yb)(III) have been investigated by using differential scanning calorimetry (DSC), thermogravimetric and differential thermal analysis (TG-DTA) and polarized optical microscopy. Except for the lanthanum complex, the other three complexes display mesogenic behavior with typical smectic mosaic textures. This is the second report on lanthanide metallomesogens since a discotic mesophase of substituted bis(phthalocyanine)lutetium was found.

Langmuir-Blodgett films of a series of new fluorescent ternary europium(III) complexes

Three europium complexes 1-methyl-4-octadecylpyridinium tetrakis(α-thenoyl trifluoroacetonato) europium(III), tris(α-thenoyl trifluoroacetonato) mono-(9-(4-hexadecylanilino)-4,5-diazafluorene) europium(III), and tris(α-thenoyltrifluoro acetonato) mono(2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline) europium(III) have been newly synthesized. They were capable of forming stable Langmuir films on pure water subphase(pH 5.6, 18 °C) with collapse pressures of 39.0, 50.0 and 20.5 mN/m, respectively. Langmuir-Blodgett films of these complexes have been prepared and studied by surface pressure-area isotherms, ultraviolet, fluorescent spectroscopy, fluorescent lifetime measurements and second-harmonic generation.

A new azo rare earth coordination compound for second-order non-linear optical Langmuir-Blodgett films

Abstract An amphiphilic lanthanide complex, ( E )-1-methyl-4-(2-(4-(dihexadecylamino)phenyl)azo)pyridinium tetrakis(1-phenyl-3-methyl-4-benzoyl-5-pyrazolonato)lanthanum(III), has been synthesized. It forms a stable Langmuir monolayer film on a pure water subphase (pH 5.6, 18°C) when spread from a chloroform solution. Langmuir-Blodgett (LB) films were prepared by transferring the monolayers onto hydrophilic substrates of quartz and calcium fluoride with a transfer ratio close to unity. From a second-harmonic generation measurement, the second-order molecular hyperpolarizability β of the complex was estimated to be about 1.4 × 10 −47 C m 3 V −2 , which is one of the largest values for azo-based, second-order non-linear optical materials reported so far. The infrared and variable-temperature ultraviolet spectra of the film are also reported.

Second-order nonlinear optical property of Langmuir-Blodgett film prepared from a novel ferrocenyl-containing lanthanide complex

Abstract Uniform multilayer LB film of a novel amphiphilic ferrocenyl-containing lanthanide complex. (E)-1-ferrocenyl-2-(N-hexadecylpyridinium-4-yl)ethylene tetrakis) 4, 4, 4-trifluoro-1-(2-naphthyl)-1,3-butanedionato)dysprosiuum(III), can be prepared by transferring the monolayer formed on pure water subphase (pH5.6. 18°C) onto hydrophilic substrates of quartz and calcium fluoride with a transfer ratio close to unity. From second harmonic generation experiments, the second-order molecular hyperpolarizability β of the dysprosium complex was evaluated to be 1.5 × 10−28e.s.u. This is one of largest values known for organometallic complexes. The UV-vis. near- and mid-IR spectroscopy for the LB film are also reported.