Shi-Zhong Liu

Organometallic Gold(i) Acetylide/Polyoxometalate Hybrid Langmuir-Blodgett Films: Preparation, Characterization, and Photoelectric Properties

A new series of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films containing an organometallic gold(i) aryleneethynylene metal complex (OMA) as the π-conjugated organometallic molecule and a polyoxometalate (POM, POM = H3BW12O40, H6As2W18O62, or H6P2Mo18O62) of the Keggin and Dawson structure as the inorganic composite, were prepared and characterized by π–A isotherms, UV-vis absorption spectra, photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable, well defined and well organized Langmuir and LB films are formed in pure water and polyoxometalate subphases. There is a quenching effect in the luminescence of the gold(i) complex when it is made into the LB films. The OMA/POM hybrid LB films display strong photovoltage effect in the UV-vis region. The photovoltage response of OMA/H6As2W18O62 can be as high as 3338 μV. OMA/POM monolayer films show good electrical conductivity, and the tunnelling current for a OMA/H3BW12O40 monolayer film amounts to 50 to approximately –100 nA when the voltage is set at ±9 V.

Dawson-type Polyoxometalate Covalently Linked to Naphthalene: Synthesis, Characterisation and Material Properties

A novel covalently linked organic–polyoxometalate (POM) hybrid compound [N(C4H9)4]6[α2-P2W17O61{P(O)C6H4C≡CC10H7}2] (NOD) was prepared by Sonogashira coupling reaction of 1-iodonaphthalene with (NBu4)6[α2-P2W17O61{P(O)C6H4C≡CH}2] (OD), and characterised by NMR, infrared spectroscopy, UV–vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. The UV–vis and luminescence spectra of NOD showed delocalisation and electron transfer in the hybrid system. The redox potential of the polyanion could be tuned by grafting organic composites on it. NOD displayed interesting electrical conductivity behaviours, photovoltage response, and photocatalytic activity.

Studies on the Preparation, Characterization and Catalytic Activity of the Nanosolid Heteropoly Acid H3PW12O40/SiO2 Using the Sol-Gel Method

A new nanosolid heteropoly acid H3PW12O40/SiO 2has been prepared by using the sol–gel method. The structure of this acid has been studied by infrared (IR) spectroscopy, X-ray diffraction (XRD) methods, transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) and specific area detector analysis. The results show that the nanosolid (diameter: 30–70 nm) is amorphous and has a large surface area (506.5 m2 g-1). Infrared spectra revealed that the skeleton of the heteropoly anion PW12O403–still exists in the silica structure. The catalytic activity was measured by monitoring the synthesis of methyl t-butyl ether (MTBE); MTBE was obtained in yields of up to 84.0% and the catalyst remained highly active after five uses.

Langmuir-Blodgett Films of Dinuclear Mercury(II)-Containing Diethynylcarbazole/Polyoxometalate Hybrids: Film Characterization Studies and Potential Optoelectronic Applications

A new family of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films, consisting of organometallic mercury acetylide (OMA) as the π-conjugated organometallic molecule and polyoxometallate (POM, POM = K5BW12O40 or Na5IMo6O24) of the Keggin and Anderson structures as the inorganic composite and docosanoic acid (DA) as the auxiliary film-forming agent, were prepared and well characterized by π–A isotherms, UV-vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that stable and well defined monolayer Langmuir and LB films are formed in pure water and POM subphases. There is a quenching effect in the luminescence intensity of the mercury complex when it is made into the LB films due to the enhanced aggregation phenomenon. These alkynylmercury(ii) based LB films exhibit interesting electrical conductivity behaviour, dependent of the characteristics of the POM used. They all reveal decent electrical conductivity, and the tunnelling current can reach ±100 nA when the voltage is set at –5 to +5 V.