Reactive Pulsed Laser Deposition of titanium nitride thin film: Optimization of process parameters using Secondary Ion Mass Spectrometry

Reactive Pulsed Laser Deposition is a single step process wherein the ablated elemental metal reacts with a low pressure ambient gas to form a compound. We report here a Secondary Ion Mass Spectrometry based analytical methodology to conduct minimum number of experiments to arrive at optimal process parameters to obtain high quality TiN thin film. Quality of these films was confirmed by electron microscopic analysis. This methodology can be extended for optimization of other process parameters and materials. (C) 2009 Elsevier B.V. All rights reserved.

Reversible double insertion of aryl isocyanates into the Ti-O bond of titanium(IV) isopropoxide

The insertion of phenyl isocyanate into titanium isopropoxide leads to the formation of a dimeric complex [Ti(O ' Pr)(2)(mu-O ' Pr){C6H5N(O ' Pr)CO}](2) (1) which has been structurally characterized. Reaction of titanium isopropoxide with two and more than 2 equiv. of phenyl isocyanate is complicated by competitive, reversible insertion between the titanium carbamate and titanium isopropoxide. The ligand formed by insertion of phenyl isocyanate into the titanium carbamate has been structurally characterized in its protonated form C6H5N{C(O ' Pr)O}C(O)N(H)C6H5 (3aH). Insertion into the carbamate is kinetically favored whereas insertion into isopropoxide gives the thermodynamically favored product. (c) 2004 Elsevier B.V. All rights reserved.

Studies of the polarographic and coulometric behaviour of aromatic nitro-compounds: I. Nitrobenzene in ethanol

A detailed polarographic (a.c. and d.c.) and coulometric investigation of nitrobenzene has been made at various pH values in the presence of different concentrations of ethanol. Below pH 4.7, two waves are apparent but above this pH, the second wave does not appear. Coulometric evidence indicates that the first and second waves correspond to the four-and two-electron processes, respectively. The coulometric method was not applicable in sodium hydroxide and sodium acetate solutions. When the diffusion coefficients (from the diaphragm cell) are used in the Ilkovic equation, no reliable conclusions can be reached for the number of electrons involved in the reduction process in alkaline solutions. The a.c. polarographic method gives evidence for the formation of species such as: C6H5NO2H22+, C6H5NO2− and C6H5NO22−. Analysis of d.c. polarographic data by Delahay's treatment of irreversible waves, indicates that the number of electrons involved in the rate-determining step is 2. In sodium hydroxide solutions, however, the first main wave is split indicating more than one rate-determining step. The results presented in this paper indicate that the first wave in the reduction of nitrobenzene is a four-electron process at all pH values. The second wave, which appears below pH 4.7, corresponds to a two-electron process irrespective of wave heights. The difference in the a.c. polarographic behaviour in acid and alkaline solutions has given evidence for the formation of species like C6H5NO2H2, C6H5NO2−, and C6H5NO22.

Dipole moments and structure of some organoselenium compounds

The dipole moments of di-p-tolyl selenide (1.74 D), di-p-tolyl selenide (1.00 D), di-m-tolyl selenide (1.66 D), di-p-anisyl selenide (2.35 D) and di-p-tolyl selenium dichloride (3.69 D) have been determined in benzene at 35°. The results are analysed in terms of mesomeric effects and internal rotation in these systems. The dipole moments of a few aliphatic selenides have been theoretically evaluated.

Spectroscopic studies of n-donor - σ-acceptor systems: Carbonyl and thiocarbonyl compounds as donors

The interaction of ketones and various thiocarbonyl derivatives with iodine has been examined. The thermodynamics of the interaction of carbonyl and thiocarbonyl donors have been discussed and compared.

Separation of vitamins A1 and A2 allied compounds by thin-layer chromatography

A simple and rapid method for the separation of vitamins A1 and A2 and allied compounds by thin-layer chromatography using kieselgel has been described. The method, however, cannot bbe applied for quantitative estimation.

Charge distribution, dipole moment and molecular structure of silyl compounds

The formal charge distribution and hence the electric moments of a number of halosilanes and their methyl derivatives have been calculated by the method of Image and Image . The difference between the observed and the calculated values in simple halosilanes is attributed to a change in the hybridization of the terminal halogen atom and in methyl halosilanes to the enhanced electron release of the methyl group towards silicon compared with carbon.

Antipyrine complexes of titanium(IV), zirconium(iv), thorium(IV) and uranium(VI) perchlorates

Antipyrine complexes of TiO2+, ZrO2+, Zr4+, Th4+ and UO2+2 perchlorates with molecular formulae TiO(Apy)4(ClO4)2, ZrO(Apy)3(ClO4)2, Zr(Apy)6(ClO4)4, Th(Apy)7(ClO4)4 and UO2(Apy)5(ClO4)2 have been prepared and characterized. The complexes are stable in air at room temperature and decompose exothermally at ~3OO °C. The i.r. study indicates the bonding of the antipyrine to the metal ion through its carbonyl oxygen. The nature of the bonding of the perchlorate and the stereochemistry of the complexes are discussed in the light of infrared spectra, conductivity in solvents of different polarity, and molecular weight measurements. From the UO2+2 group frequencies, the force constant K and rU-o are found to be 6.29 × 105 dynes/ cm-1 and 1.74 Å, respectively.

Electric dipole moments and molecular structure of aliphatic nitro compounds and oximes

Using the treatment of Smith et al. charge distributions in and consequently the dipole moments of some aliphatic nitro compounds and oximes have been evaluated. The mesomeric moment derived as a difference between the calculated and the observed values gives a clear picture as to how the positive (+M) and the negative (-M) mesomeric effects operate in such systems.

Preparation and properties of peroxy titanium malonate

The method of preparation and physicochemical properties of peroxy titanium malonate, TiO2(OOC)2CH2·3H2O are given. The reasons for the poor complexing tendency of malonic acid are discussed. The nature of the bonds between titanium and the peroxy as well as malonate groups is assigned from spectrophotometric and infra-red absorption studies.

Preparation and properties of peroxy titanium malonate

The method of preparation and physicochemical properties of peroxy titanium malonate, TiO2(OOC)2CH2·3H2O are given. The reasons for the poor complexing tendency of malonic acid are discussed. The nature of the bonds between titanium and the peroxy as well as malonate groups is assigned from spectrophotometric and infra-red absorption studies.

The Raman spectra of organic compounds -Part I. Methyl, ethyl, n-propyl and n-butyl alcohols

The Raman spectra of methyl alcohol, ethyl alcohol, n-propyl alcohol and n-butyl alcohol have been recorded using λ 2537 excitation. 35, 49, 45 and 51 Raman lines respectively have been identified in the spectra of these alcohols, in addition to the rotational 'wings'. In each case, a large number of additional lines have been recorded. The existence of Raman lines with frequency shifts greater than 3800 cm.-1, first reported by Bolla in the spectrum of ethyl alcohol, has been confirmed. Similar high-frequency shift Raman lines have also been recorded in the spectrum of methyl alcohol. They have been assigned as combinations. Proper assignments have been given for the prominent Raman lines appearing in the spectra of these alcohols.