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In the present paper, the preparation and characterization of an improved solid-state pH sensor are described. The sensor is based on anodically electrodeposited iridium oxide film, as a pH-sensing layer. Merits of the present sensor include (i) excellent adhesion of the pH sensitive layer to the substrate, (ii) excellent reproducibility of sensor fabrication, (iii) faster preparation procedure, and (iv) low cost of the titanium substrate. These advantages are realized by combining acid-etched titanium as the electrode substrate with an optimized electrodeposition solution consisting of Ir[Cl.sub.4] as an iridium source, hydrogen peroxide, potassium oxalate, and potassium carbonate. Heating the electrodeposition solution to 90 [degrees]C reduced the time required for solution development from ~3 days to 10 min. The pH-sensing layer is protected with a layer of Nafion and a microporous polyester membrane. The improved sensor showed a super-Nernstian response (-73.7 [+ or -] 1.2 mV/pH unit) in the pH range of 1.5-11.5. The present pH sensor, fabricated in a tubular form, is used as a detector in a flow injection analysis (FIA) system for pH measurements. Optimization of the FIA experimental parameters resulted in a linear dependence of peak heights on the pH of the injected samples in the pH range of 2-11.

Gold exhibits homogeneous nucleation and growth on polycrystalline titania surfaces. Exposure of very small Au particles to ambient air at room temperature causes rapid sintering and migration to titania crystallite grain boundaries.

This paper examines the various steps involved in the organic synthesis involving monocarbanionic organometallic reagents. Research reveals that these compounds in the presence of titanium derivatives behave as dicarbanionics when reacting with electrophiles.

Research was conducted to examine the Ti-catalyzed, asymmetric oxidation of alkyl aryl sulfides by enantiomerically pure hydroperoxides. Several alkyl aryl sulfides were utilized for the evaluation of the scope of this catalytic, enantioselective sulfoxidation wherein the size of the alkyl group and the electronic properties of the aryl substituent were analyzed. Results indicate that the asymmetric sulfoxidation afforded high yields of methyl phenyl and p-tolyl alkyl sulfides.

Analysis of the enantio- and diastereoselective Diels-Alder reaction of cyclopentadiene with N-acyloxazolidinones, in the presence of alpha,alpha, alpha', alpha'-tetraaryl-1,3-dioxolane-4,5-dimethanolate (Ti-TADDOLate) reveals that the endo:exo ratio in Diels-Alder reaction and in the stoichiometric reaction are similar. The endo:exo ratio depends upon tosylato and chloride ligands attached to the titanium atom as endo diastereomer. The intermediate produced in the Diels-Alder reaction mediates the reaction mechanism.

The chlorosilane promotes the catalytic behaviour of titanium powder, which is then used for various acetal and carbonyl coupling reactions, heterocycle synthesis and reductions. The catalyst mixture is chemoselective and reveals a template effect for intramolecular processes. The chemically activated titanium behaves differently in aromatic and aliphatic substrates.

Research was conducted to address the shortcoming of previous studies on the synthesis of vicinal diamines through reductive dimerization of imines using low valent titanium (LVT) reagent which afforded low yields due to the formation of amines. The present study is aimed at directing the reaction to follow a bimolecular process in preference to a unimolecular process. The VT reagent, TiCl3-Li-THF, offered substantial improvements over the previous method by reducing reaction time, simplifying the procedure and augmenting the yield of the desired diamines.

A hydrated Sharpless reagent (1:2 Ti/chiral tartrate) allows the resolution of (+/-)-5-(3, 5-di-t-butyl-4-hydroxyphenyl)methyl-4-thiazolidinone, prepared from 3, 5-di-t-butyl-4-hydroxybenzaldehyde and rhodanine. When (+)-tartrates are used, the tert-butyl hydroperoxide oxidizes the (+)-enantiomer faster, leaving a (-)-enriched ketone. Conversely, using (-)-tartrates leaves behind a (+)-enriched ketone. The 94% enantiomeric purity is further enhanced by crystallization, which precipitates only the enreacted racemic ketone. The bulkier diisopropyl tartrate gives a 5% better optical yield than diethyl tartrate.

Studies have shown that the pyridine nitrogen complexes can be denitrogenated under mild conditions and in a cyclic manner when they are treated with an electrophile such as [(C[H.sub.3]).sub.3]SiCl. Synthetic, isotopic labeling and mechanistic studies of the denitrogenation process are described.

The cationic monocyclopentadienyl titanium catalysts that selectively trimerize ethylene to 1-hexene, by virtue of a pendant arene moiety on the Cp ligand are presented.

Ferrocene derivatives may be useful for materials and catalysts as they show unique optical, thermal and redox behaviour. Alkylferrocenes are usually derived via a two-stage protocol, and the development of a mild borohydride-based reagent system has been described. Alkylferrocenes were obtained in high yields through the reduction of alpha-ferrocenyl aldehydes, ketones and alcohols, utilizing titanium(IV) chloride and triethylsilane.

The organized assembly of acetylene molecules on titanium resulted in a new form of acetylene cyclotrimerization.

The titanium-catalyzed carbonyl-olefin and carbonyl-alkyne reductive cyclization reactions result in the formation of a metallacyclopentane with concomitant formation of a carbon-carbon bond because both ketones and aldehydes are good substrates for the titanium-catalyzed reductive cyclization reactions. The cis selectivity of the carbon-carbon bond forming reaction is complimentary to the trans selectivity obtained in related samarium-mediated cyclizations.

The reductive cyclization of an alkene or an alkyne with a heteroatom containing functional group is now possible with the help of an early transition metal catalysts like titanium. Early transformtion metal catalysts are often incompatible with polar functional groups, but in this type of transformation, enones containing allylic ethers or esters are tolerated. Efforts towards the development of more synthetically useful methods including those that afford more functionalized and/or enantiomerically enriched products are in progress.

Solid sampling electrothermal atomic absorption spectrometry using the boat technique and a transversely heated graphite tube was applied to direct analysis of pieces of high-purity titanium for Al, As, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sn, and Zn. It was found that the enthalpy for alloy formation between the analyte element and the titanium matrix plays an important role in the atomization mechanism. While the elements Ca, Cu, K, Mg, Mn, Na, Pb, and Zn could be determined without any modification, carbon powder was added to facilitate the vaporization of As, Co, Fe, Ni, and Sn and to eliminate the matrix interferences in the determination of Al and Cr. Quantification was performed by using a calibration curve obtained with use of aqueous standard solutions. Accuracy was checked by comparison of the results with those of three other methods. Sample amounts of up to 30 mg per atomization were applicable. The limits of detection for the 15 elements assayed were between 0.02 (Mg) and 30 ng/g (Sn).

Solid sampling electrothermal atomic absorption spectrometry using the boat technique and a transversely heated graphite tube was applied to direct analysis of pieces of high-purity titanium for Al, As, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sn, and Zn. It was found that the enthalpy for alloy formation between the analyte element and the titanium matrix plays an important role in the atomization mechanism. While the elements Ca, Cu, K, Mg, Mn, Na, Pb, and Zn could be determined without any modification, carbon powder was added to facilitate the vaporization of As, Co, Fe, Ni, and Sn and to eliminate the matrix interferences in the determination of Al and Cr. Quantification was performed by using a calibration curve obtained with use of aqueous standard solutions. Accuracy was checked by comparison of the results with those of three other methods. Sample amounts of up to 30 mg per atomization were applicable. The limits of detection for the 15 elements assayed were between 0.02 (Mg) and 30 ng/g (Sn).