Tetrakis(diethylamido) titanium (TDEAT) interactions with SiO2 and Cu substrates

X-ray photoelectron spectroscopy (XPS) is used to characterize the chemical interactions of tetrakis(diethylamido) titanium (TDEAT) with SiO₂ and Cu surfaces under ultrahigh vacuum (UHV) conditions. XPS studies show that TDEAT dissociatively chemisorbs on SiO₂ at room temperature or above, resulting in Ti---N bond scission, and Ti---O bond formation. No Ti carbide or Si carbide formation is observed. In the presence of co-adsorbed NH₃, Ti---N bond formation is enhanced and is stable at temperature up to 900 K in UHV. Continuous exposures of TDEAT on SiO₂ at 500 K produce both Ti oxides and nitride formation. The presence of an overpressure of NH₃ enhances Ti nitride formation. In contrast, TDEAT physisorbed on Cu at 120 K and annealed to 500 K results in desorption of Ti-containing species from the surface. Successive exposures of TDEAT on Cu at 500 K yield a Ti-alkyl reaction product. The presence of NH₃ does not significantly alter TDEAT interaction with Cu.     

Twin boundaries in antimony(V)-doped rutile titanium(IV) oxide

Titanium-antimony oxides formed by the calcination of precipitates at elevated temperatures contain low concentrations of antimony(V) within the rutile titanium(IV) oxide lattice. Electron microscopy has revealed the presence of planar defects which have been shown by electron diffraction to be twin boundaries. Energy dispersive X-ray analysis has not revealed any evidence for the segregation of antimony to these planar faults. No evidence has been found for the occurrence of crystallographic shear planes which are frequently found in rutile when doped with trivalent cations.     

Thio sol-gel synthesis of titanium disulfide thin films and nanoparticles using titanium(IV) alkoxide precursors

Titanium tetraisopropoxide reacts with hydrogen sulfide in butylamine solvent at room temperature to form an amorphous titanium alkoxy-sulfide which can be converted to crystalline titanium disulfide by heat treatment in a flowing hydrogen sulfide gas stream. The reaction has been studied using infrared and Raman spectroscopy, gas chromatography-mass spectrometry, X-ray diffractometry and energy-dispersive X-ray analysis measurements. Based on these studies, it is shown that a partially thiolysed alkoxide precursor forms through the replacement of a limited number of alkoxy groups by hydrosulfide moieties. This alkoxy-hydrosulfide is believed to form following a thiolysis-condensation mechanism similar to the hydrolysis-condensation process that occurs during the corresponding oxide sol-gel reaction. The alkoxy-hydrosulfide species can then be completely thiolysed at 800 °C in a stream of hydrogen sulfide to yield pure, hexagonal titanium disulfide in either film or particulate form.     

Optically driven actuators using poly(vinylidene difluoride)

Optically driven actuators have a feature of a non-contact method supplied by light energy. A new method is proposed with three poly(vinylidene difluoride) (PVDF) cantilevers as the legs and a polymer film as the body. The PVDF cantilevers are coated with silver on one surface. When one side of the cantilever is irradiated by a laser beam, an electric field is produced along a cross-section of the cantilever by the pyroelectric effect and a mechanical displacement occurs by the piezoelectric effect. Its response time and its generated force are measured experimentally. Two types of optically driven actuators using PVDF film are proposed to move using different characteristics.     

Preparation and characterization of thermally evaporated titanium phthalocyanine dichloride thin films

Titanium phthalocyanine dichloride (TiPcCl₂) thin films are prepared on glass substrates by vacuum-sublimation technique. The optical constants of thin films are obtained by means of thin film spectrophotometry. Planar structures for the study of electrical properties are fabricated with TiPcCl₂ as active layer and silver as the contact electrodes. The effects of post-deposition annealing on the optical band gap have been studied. The optical transition is found to be direct allowed in nature. The invariance in the optical band gap shows the thermal stability of the material. The activation energies are determined using the Arrhenius plots between electrical conductivity and inverse temperature. The variation in activation energy with post-deposition annealing is investigated. The unit cell dimensions of TiPcCl₂ thin films are also determined by indexing the powder diffraction data. The variations of the surface morphology and grain size with annealing have also been studied.     

Highly excited and autoionizing states in the spectrum of triply ionized titanium Ti(IV)

The spectrum of Ti(IV) excited in a vacuum spark was investigated in the range 250–900 Å with high resolution. Eighty-four lines were measured and identified as transitions from the 3p⁶ns, 3p⁶np, and 3p⁶nf configurations, where n ≤ 8, ≤ 10, and ≤ 8, respectively, and from the 3p⁵3d² and 3p⁵3d⁴s configurations. The lines due to the transitions from the autoionizing levels of the 3p⁵3d² and 3p⁵3d⁴s configurations were also observed and their widths were measured. The experimental data were compared with the results obtained by calculations using the Hartree-Fock method and semiempirical calculations.     

Electron transfer spectrum of caesium rhodium (IV) hexachloride at relatively low wave-number

The dark green crystals of Cs₂RhCl₆ have electron transfer bands at lower wave-number than any other hexahalide complex yet studied. The transitions are compared to those occurring in analogous compounds, and the influence of covalent bonding on the orbital energies is discussed.     

Preparation and study of microstructures, optical properties and oscillator parameters of titanium (IV) oxide (TiO2) film

In this study, Titanium (IV) Oxide (TiO₂) film has been prepared and characterized by X-ray diffraction (XRD). The XRD pattern of TiO₂ film of anatase phase exhibit very sharp peaks at 25° and 47.85°. According to Scherrer??s formula the grain size of anatase (101) phase TiO₂ nananoparticle is 38.5 nm. The optical properties and constants of TiO₂ film of thickness (4 ??m) have been investigated at room temperature. The transmittance, reflectance and absorbance spectra are measured in the wavelength range (340?C900 nm). Optical constants of TiO₂ film are derived from the transmission spectra and the refractive index dispersion of the film. The oscillator energy, E ₀ dispersion energy, E _d , the static refractive index, n ₀, and other parameters have been determined by the single oscillator Wemple-DiDomenico method. This film can be used in the form of thin film in dye-sensitized solar cells.     

Precipitation of gold nanoparticles on the quartz surface modified by titanium (IV) butoxide

Gold nanoparticles have been precipitated on the surface of quartz slides covered with titanium (IV) butoxide. UV irradiation of modified quartz slides immersed into water solutions of hydrogen tetrachloroaurate of different concentrations (2.5 × 10⁻⁴–1.0 × 10⁻² M) has been used for this purpose. Properties of produced samples have been investigated by UV–Vis spectroscopy, IR spectroscopy, SEM-EDX, TGA, and AFM. According to the obtained data, produced gold particles are distributed on modified quartz surface very uniformly and the average size of gold particles is about 30–50 nm.     

二(2-苯基-8-羟基喹啉)锌和喹啉锌的合成和荧光性质

合成了一种新型二(2-苯基-8-羟基喹啉)锌配合物。利用元素分析、红外吸收光谱等方法表征了结构,并对比研究了二(2-苯基-8-羟基喹啉)锌和喹啉锌的荧光性质,前者的激发光谱在465nm处出现了较强的吸收,并且发射峰位置发生了明显的红移,由喹啉锌的495nm移至2-苯基-8-羟基喹啉锌和喹啉锌的521nm处。对有关的吸收峰的归属进行了讨论,初步认为苯环的取代增加了有机配体π-π键的共轭程度,使HOMO-LUMO之间能隙变小,引起发射峰红移。     

Synthesis and Fluorescence Properties of Lanthanide (III) Perchlorate Complexes with Bis(benzoylmethyl) Sulfoxide

A ligand with two carbonyl groups and one sulfinyl group has been synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, ¹H NMR and UV spectra. The results indicated that the composition of these complexes is REL₅(ClO₄)₃·3H₂O (RE = La(III), Pr(III), Eu(III), Tb(III), Yb(III), L = C₆H₅COCH₂SOCH₂COC₆H₅). The fluorescent spectra illustrate that both the Tb (III) and Eu (III) complexes display characteristic metal-centered fluorescence in solid state, indicating the ligand favors energy transfer to the excitation state energy level of them. However, the Tb (III) complex displays more effective luminescence than the Eu (III) complex, which is attributed to especial effectively in transferring energy from the average triplet energy level of the ligands (T) onto the excited state (⁵D₄) of Tb (III) than that (⁵D₀) of Eu (III), showing a good antenna effect for Tb(III) luminescence. The phosphorescence spectra and the relationship between fluorescence lifetimes and fluorescence intensities were also discussed.     

离子对电荷转移配合物[NO2Py]x[Co（mnt）2]的合成、光谱和磁性表征

合成了两种新的离子对电荷转移配合物[NO2Py]x[Co(mnt)2],(NO2Py=1-(4-ritrobenzyl)pyridinium;mnt=maleonitriledithiolate;x=1or2时分别对应配合物2和1),并用元素分析和红外光谱、电喷雾质谱和固体反射电子光谱等谱学方法对两种配合物进行了表征.两种配合物在77K到300K范围内的变温磁化率结果表明,配合物2是抗磁性物质,经Pascal′s常数校正后的配合物1的磁化率遵循改进的Bleaney-Bowers方程,实验值和理论计算值能很好的吻合,非线性最小平方二乘法拟合所得的最佳拟合参数为g=2.392,2J/k=5.9K和θ=-4.9K,一致性因子R=7.20×10-9(R=∑(χobsi-χcalcdi)2/∑(χobsi     

2D-NMR Studies on Bis(Amidinohydrazones). I. A Proton-Carbon Heteronuclear Shift Correlation Study on the Enzyme Inhibitors Methylpropylglyoxal Bis(Amidinohydrazone) and Butylmethylglyoxal Bis(Amidinohydrazone)

The first 2D-NMR study on bis(amidinohydrazones) [‘(guanylhydrazones)’] is reported. Heteronuclear shift correlation (HETCOR) experiments were performed on the enzyme inhibitors methylpropylglyoxal bis(amidinohydrazone) (MPGBG) and butylmethylglyoxal bis(amidinohydrazone) (BMGBG). The results obtained made possible the unambiguous assignment of the previously unassigned resonances of the side-chain carbon atoms of MPGBG. The results indicate that the chemical shifts of the protons of the propyl side chain of MPGBG are positively correlated to the ¹³C chemical shifts of the corresponding carbon atoms. The chemical shifts of the carbon atoms of the propyl side chain decrease as a function of the position of the atom in the side chain, the terminal methyl group having the lowest shift value. These results are in full agreement with previous results on the analogous compound dipropylglyoxal bis(amidinohydra- zone), whose side-chain carbon resonances were assigned using totally different techniques. In the case of BMGBG, however, HETCOR contour plots clearly indicate that there is no correlation between the chemical shifts of the protons of the butyl side chain and the 13C chemical shifts of the corresponding carbons. Because the 200 MHz proton spectrum of BMGBG is not fist-order, only the 1 3 resonance～ of the methyl substituent and the resonances of carbons 1 and 4 (but not those of carbons 2 and 3) of the butyl side chain could be assigned on the basis of the HETCOR study. Yet, the results gave a rough estimate of the previously unknown chemical shifts of the protons bound to butyl carbon atoms 2 and 3.     

Europium-151 Mössbauer effect study of relaxation in two bi(pentamethylcyclopentadienyl) europium(II) complexes

Europium-151 Mössbauer spectra of two bis(pentamethylcyclopentadienyl) europium complexes have been recorded at 78K. The broad spectra with linewidths of 14.2 and 11.6 mm/s, and with isomer shifts of –12.5 and –12.8 mm/s, relative to EuF₃ may be understood in terms of spherical relaxation of the effective hyperfine field.     

Coexistence of Magnetism and Conductivity in Bis(ethylenediseleno) Tetrathiafulvalene (BEST) with Octahedral Anions Hexacyanoferrate (III)and Nitroprusside

Using an accurate density-function method, we explore the coexistence of the magnetism and conductivity in bis(ethylenediselena)-tetrathiafulvalene (BEST) with the paramagnetic hexacyanoferrate(III) [Fe(CN)₆]^3- or the photochromic nitroprusside anion [Fe(CN)₅NO]^2-. The total and partial densities of states, and the atomic spin magnetic moments are calculated and discussed. It is found that the up- and down-spin total densities of states (DOS) are continuous in the vicinity of the Fermi level, there is overlap between the HOMO and LUMO in the up-spin subbands and the down-spin subbands, which reveals that these types of compounds have conductive properties. From the total and partial densities of states and atomic spin magnetic moments, it is shown that the spin magnetic moments of (BEST)₄[Fe(CN)₆] is mainly assembled at the iron atom and the cyanogen radical, and the spontaneous magnetic moments for (BEST)₂[Fe(CN)₅NO] come from iron atom, cyanogen and nitric oxide radical. To our best knowledge, it is the first theoretical study on the coexistence of the magnetism and conductivity of these compounds.     

Syntheses and Fluorescence Properties of Two Novel Lanthanide (III) Perchlorate Complexes with Bis(benzylsulfinyl)methane

A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane, was synthesized by a new method and its two lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, ¹HNMR and UV spectra. The results indicated that the composition of these complexes was REL_2.5(ClO₄)₃·3H₂O (RE = Tb (III), Dy (III), L = C₆H₅CH₂SOCH₂SOCH₂C₆H₅). The FT-IR results revealed that the perchlorate group was bonded with the lanthanide ion by the oxygen atoms, and the coordination was bidentate. The fluorescent spectra illustrated that both the Tb (III) and Dy (III) complexes displayed characteristic fluorescence in solid state, especially for the Tb (III) complex, the peak of ⁵D₄ → ⁷ F₅ of the Tb (III) ion in 544 nm was stronger than that of others. It indicated that the Tb (III) complex could emit purer green fluorescence. By analysis fluorescence and phosphorescence spectra, it was found that the ligand had the advantage to absorb energy and transfer it to the Tb (III) and Dy (III) ions. The phosphorescence spectra and fluorescence lifetimes of the complexes were also measured.