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A novel tripod-chromogenic sensor based on a s-triazine and thiazolidine-2,4-dione ring (TCST)was designed, synthesized, and applied as a colorimetric probe in aqueous solutions of dimethyl sulfoxide (DMSO). The probe showed a highly sensitive and selective colorimetric sensor for naked-eye detection of L[i.sup.+], changing from colourless to yellow. The probe's detection limit toward L[i.sup.+] was found to be 1.2 [micro]M. The result of the Job plot analysis showed 1:1 stoichiometry for the interaction between the tripod chemosensor and L[i.sup.+] and this result was confirmed by [.sup.1.H] NMR titration experiments. The probe can also be used for biological activities depending on the results of microbial tests. Key words: chemosensor, colorimetric, naked-eye detection, L[i.sup.+] sensing, s-triazine, thiazolidine-24-dione. Nous avons concu et synthetise un nouveau capteur chromogene de type tripode contenant un noyau central striazine et des cycles thiazolidine-2,4dione (TCST)et nous l'avons employe comme sonde colorimetrique dans des solutions aqueuses de dimethylsulfoxyde (DMSO). Nous avons observe que cette sonde agit comme capteur colorimetrique haute-ment sensible et selectif pour la detection a l'ceil nu de l'ion L[i.sup.+], qui se caracterise par un changement de couleur passant d'incolore a jaune. La limite de detection de la sonde a l'egard de l'ion L[i.sup.+] etait de 1,2 [micro]M. L'analyse de la courbe de Job a montre que l'interaction entre le capteur chimique de type tripode et l'ion L[i.sup.+] presentait une stc chiometrie de 1:1. Ce resul-tat a ete confirme au moyen d'experiences de titrage par RMN [.sup.1.H]. La sonde peut egalement etre utilisee comme molecule bioactive selon les resultats de tests microbiens. [Traduit par la Redaction] Mots-cles: capteur chimique, colorimetrique, detection a l'ceil nu, detection d'ions L[i.sup.+], striazine, thiazolidine-24dione., Introduction Lithium (Li) is an important metal with natural sources in the Earth's crustal rocks, seawater, and mammals. (1,2) Among the metal ions, this soft metal has an undeniable industrial [...]

We report techniques for in-situ abundance measurements of the light-lithophile elements (LLE; Li, Be, and B) in silicate glasses by laser-ablation inductively coupled mass spectrometry (LA-ICP-MS), and compare the analytical performance of a sector field and quadrupole mass analyzer for these measurements. LA-ICP-MS is shown to be an effective means of determining LLE abundances at spatial scales between 25 and 100 [micro]m. Detection limits depend on instrumental sensitivity and ablation rate, but can be in the low- to sub-ng/g range. Measured ion yields for [sup.7]Li, [sup.9]Be, and [sup.11]B ion, normalized to [sup.43]Ca as an internal standard, remain largely constant during ablation, although [sup.11]B shows a relative increase once the ablation crater aspect ratio exceeds ~1. Surficial contamination, particularly of B, can be removed rapidly via a short pre-ablation (~20 pulses) immediately prior to analysis. The sector field ICP-MS provided considerable improvements in analytical performance over the quadrupole mass analyzer, although longer magnet settling times result in greater duty cycle losses. Calculated detection limits for a given set of ablation conditions are 20-90 times lower, and useful yields (the ratio of atoms ablated to counts detected) are 20-75 times greater for the sector field instrument. Analysis of reference glasses shows that LA-ICP-MS provides accurate measurements of Li, Be, and B contents in silicate glasses over a range of compositions (komatiite to rhyolite). LA-ICP-MS also offers similar accuracy and precision and marked improvements in sample throughput compared to secondary ion mass spectrometry (SIMS) analysis of LLE abundances, although SIMS has higher useful yield and thus provides better spatial resolution. Keywords: Light-lithophile elements (Li, Be, B), laser ablation ICP-MS, SIMS, geochemical reference standards

The frequency stability of microwave oscillators have improved considerably depending on very low loss, single crystals with frequency temperature self compensation of the resonance mode. From the isotropic materials like the calcium and lithium fluoride only one form of resonance is selected which shows whispering gallery (WG) mode electromagnetic field structure.

Digital color analysis (DCA), utilizing colors themselves or digital information of colors, can not only be applied to various quantitative analysis using chromaticity coordinates but can also be used to develop suitable sensors for visual colorimetry based on the characteristics of human visual perception by virtual simulations based on digital color information. To achieve a clear visual color variation for lithium ion determination, we designed and prepared a color-changeable film sensor (film optode) by the use of two kinds of lipophilic dyes, KD-C4 and KD-M11, whose colors and [pK.sub.a] values are different. This film sensor is a plasticized PVC membrane containing the mixture of two kinds of dyes with the lithium ionophore TrD14C4 and the lipophilic anionic additive tetrakis[3,5-bis(trisfluoromethyl)phenyl]borate sodium salt dihydrate. The simulation of the color variation using the mixed dyes was evaluated by plotting the values on a uniform chromaticity scale diagram in a*b* coordinates, after converting the tristimulus values of each dye into its L*a*b* values. When the lithium ion concentration was actually determined by the PVC film optode containing the mixed dyes whose molecular ratio of KD-C4/KD-M11 was 3:1, the hues of red [right arrow] orange [right arrow] yellow [right arrow] green [right arrow] blue could be realized in the range of [10.sup.-6]-1 M. This observed color variation was similar to the result of the virtual simulation based on DCA.

The mineral phases of 33 eclogite and garnet clinopyroxenite samples from various tectonic settings were analysed for Li by secondary ion mass spectrometry (SIMS). In all samples, Li is preferentially incorporated into clinopyroxene (0.4 to 80 [micro]g/g), whereas co-existing garnet contains only minor amounts of Li (0.01 to 3.7 [micro]g/g). When present, glaucophane shows Li abundances which are similar to those of clinopyroxene, but phengite contains significantly less Li than clinopyroxene. Additional phases, such as amphibole, quartz, clinozoisite and kyanite, have low Li concentrations (< 1 [micro]g/g). No correlation is apparent between the Li contents and major-element compositions of clinopyroxene or garnet. On the basis of both measured Li concentrations in clinopyroxene and estimated Li abundances in the whole rocks, the investigated samples can be subdivided into high-Li and low-Li groups. These groups coincide with the mode of origin of the rocks. Metabasaltic (metagabbroic) eclogites from high-pressure terranes belong to the high-Li group whereas, except for one eclogite, all kimberlite- and basanite-hosted xenoliths have low Li contents. Samples from eclogites and garnet clinopyroxenites associated with orogenic peridotites fall into both groups. It is suggested that the high-Li eclogites originated from basaltic oceanic crust whereby the notable Li enrichment of some samples was probably caused by low-temperature hydrothermal alteration prior to subduction. Furthermore, the low-Li eclogites and garnet clinopyroxenites may represent high-pressure cumulates from mafic melts percolating through the mantle.

Research has been conducted on the pentadienyl cation, anion and metalated pentadienes and their equilibrium geometries and rotational barriers. The use of ab initio calculations is described.

An equation for computing the soft mode frequency and Curie temperature was used to investigate the defect structure of nonstoichiometric lithium niobate crystals. The Curie temperature was obtained for three possible kinds of defects: oxygen vacancies, niobium vacancies and lithium vacancies. Good quantitative agreement between the computed and experimental data for the lithium vacancy model showed that this model is the most accurate for representing the defect structure of nonstoichiometric lithium niobate.

The gas-phase hydroxyl (OH) radical emission occurring in the thermal decomposition of lithium hydroxide (LiOH) has been studied. Temperature programmed reaction experiments in a vacuum flow tube reactor were carried out between 500 to 1300 K at a pressure of 2 Torr. Laser-induced fluoroscopy and quadrupole mass spectrometry were used in measuring the volume of OH and other gas products. Results indicated that OH radicals may have originated from the surface OH groups on Li2O or the residual LiOH in the LiOH/Li2O solid solution. The OH production may be explained by the partial equilibrium in the reaction LiOH + 1/4O2 1/2Li2O + OH.

A newly developed nonlinear crystal belonging to the borate family, lithium tetraborate Li2B4O7 (LB4), has excellent properties below 180 nm and allows the generation of wavelengths down to 170 nm with an all-solid state laser system. This was gleaned from a characterization of the newly grown crystal by the Czochralski method. A comparison with a lithium triborate sample showed that it performs better in the vacuum ultraviolet spectral region below 180 nm. Its effective nonlinearity is maximized under the conditions of 90 degree-phase matching.

A method for the synthesis of trimethyl alpha-keto esters and dimethyl alpha-keto dithioacetals was developed based on a [tris(methylthio)methyl]lithium-catalyzed process. The synthetic strategy utilizes aromatic derivatives of acyl chlorides as starting materials for the target compounds. The highest yield was obtained by the reaction of N,N-diethylamides with [tris(methylthio)methyl]lithium due to the smaller amount of reagent that was required for the reaction compared to aromatic esters.

The kinetics of aldol reactions of alpha-sulfinylcyclohexanones with different esters was analyzed during the reaction of lithium enolates derived from esters and lactones with 2-(p-tolylsulfinyl)cyclohexanones. The synthetic strategy was characterized by the evolution of the alpha-sulfinylcyclohexanones with complete control of the stereoselectivity in both the carbonyl and enolate prochiral centers. The formation of mixtures of two diastereoisomers depends on the equilibration of the enolates.

The highly deuterated or tritiated LiB3H4 was synthesized by a one-spot process from Li3H which was synthesized from lithium gas. The highly selective LiBH4 exhibited a level of reactivity that is between LiAlH4 and NaBH4 with a reducing power that can be modified by catalysts. The reagent also exhibited excellent selectivity during simple aldehyde reductions including the complete reduction of an acid chloride to R-CH2-OH.

Irradiation was performed on pure and magnesium doped crystals of LiF with gamma rays utilizing 241Am and 60Co sources. Measurement of the photoluminescence and optical absorption were conducted simultaneously with the isochronal anneal. The ubiquitous nature of the F3+ defects was revealed and was found to be highly luminescent but was considered as hidden due to its non-appearance in optical absorption. Luminescence was also observed in the Z3, Z2, R1 and F2 defects.

The structure of lithium diisopropylamide (LDA) is analysed using 6Li and 15N nuclear magnetic spectroscopy in toluene/pentane solutions with monodentate and bidentate ligands. The study illustrates the use of strongly coordinating diamine-trans-NmNm N', N'-tetramethyl-1,2-cyclohexanediamine in the identification of ethereal ligand relative binding constants on the LDA dimer fragment. Further structural information on LDA-mediated dehydrohalogenations is given.

A novel method for the transformation of benzotriazole derivatives into carbanions was developed based on the utilization of lithium for C-benzotriazole bond scission. The synthetic process for the transformation of N-substituted benzotriazoles was characterized by the formation of carbanions based on the reaction of electrophiles with N-(diphenylmethyl)benzotriazole and N-benzylbenzotriazole. Furthermore, the easy scission of carbon-nitrogen bonds mediated the transformation of benzotriazole derivatives into carbanions.

The 6Li-13C REDOR experiment is a study of the solid-state structure of the tetramethylethylenediamine (TMEDA) complex of fluorenyllithium. This experiment used Li-enriched samples with natural abundance C-signal which made data interpretation and sample preparation easier. It was observed that the dipole-dipole couplings between the Li cation and the C nuclei yield direct structural information. The position of the Li cation, with respect to the fluorenyl framework, is determined within plus-minus 0.2 angstrom.

The imporant roles of the cluster structure and the cooperative interactions of the meals in that structure were analyzed through the utilization of hybrid density functional B3LYP procedure. Results have established a pathway for a dimer to undergo conjugate addition. Lithium atoms were shown to have facilitated the reaction by cooperatively reacting with copper atoms during carbocupration and and conjugate addition.

The synthesis, structure, and reactivity properties of a novel molecular gallium phosphonate cage which contains flanked lithium ions were presented through analytical and spectroscopic techniques and single-crystal X-ray diffraction study. Data revealed that compound 1 from the first molecular ionic gallophosphonate cage acts as a precursor for the molecular sieves and ion conductors synthesis, unreactive toward air and moisture at room temperature.

The molecular structure and experimental behavior of the Li+(cryptand [2.1.1])e- electride were analyzed to characterize the inter-electron magnetic spin coupling and conductivity of the lithium electride. Analysis of the Li+(cryptand [2.1.1])e- electrides indicated the field dependence of magnetic susceptibility. The electride also exhibited weak spin anisotropy and electron-electron coupling reactions that were affected by small changes in crystal packing. Furthermore, steric interactions contributed to the dimerization of the electride.

The dynamic behavior and structure of the allylic lithium was altered by modifications in the site of the pendant ligand. The sequential metalation/silylation of a propene with a pendant ligand led to the formation of allylic lithium compounds. Nuclear magnetic resonance of the allylic lithium compounds also indicated the presence of C-Li bond exchange, inversions at the lithium-bound carbon and a 1,3 lithium sigmatropic shift.

Conducting organic polymers are evaluated in terms of their prospective usefulness in meeting the demands for rechargeable batteries with high specific energy and power. It has been recognized that the highest specific energy and energy density may be provided by ion-transfer battery design with a lithium-inserting carbon negative (or metallic lithium) combined with metal oxide polymer or metal sulfide positive that is capable of inserting lithium ions during discharge and give them off during charging.

A method for the synthesis of trimethyl alpha-keto esters and dimethyl alpha-keto dithioacetals was developed based on a [tris(methylthio)methyl]lithium-catalyzed process. The synthetic strategy utilizes aromatic derivatives of acyl chlorides as starting materials for the target compounds. The highest yield was obtained by the reaction of N,N-diethylamides with [tris(methylthio)methyl]lithium due to the smaller amount of reagent that was required for the reaction compared to aromatic esters.

The kinetics of aldol reactions of alpha-sulfinylcyclohexanones with different esters was analyzed during the reaction of lithium enolates derived from esters and lactones with 2-(p-tolylsulfinyl)cyclohexanones. The synthetic strategy was characterized by the evolution of the alpha-sulfinylcyclohexanones with complete control of the stereoselectivity in both the carbonyl and enolate prochiral centers. The formation of mixtures of two diastereoisomers depends on the equilibration of the enolates.

The addition of sulfur to LiC6H3-2,6-Trip2 and the subsequent hydrolysis of the intermediate product led to the formation of HSC6-2,6-Trip2 which was also treated with n-BuLi to produce lithium thiolate derivatives. The resulting lithium thiolates such as (LiSC6H2-2,4,6-Ph3)4.C7H8, (LiSC6H3-2,6-Mes2)3.C6H14 and (LiSC6H3-2,6-Trip2)2 exhibited tetrameric, trimeric and dimeric structures respectively. Furthermore, the tetrameric and trimeric lithium thiolates are composed of four- and three-rung ladders that are terminated at the tetrameric/trimeric stage due to steric factors.

An examination of the utility of the cyclization of acetylenic vinyllithiums revealed that exo-dig cycloisomerization of a vinyllithium tethered to an acetylenic unit provides a simple and efficient technique for preparing synthetically useful five- and six-membered bisexocyclic 1,3-dienes. The 5-exo closure tolerates aryl-, silyl-, or alkyl-substituents at the distal acetylenic carbon, while the 6-exo process is less easy and appears to be limited to substrates bearing an anion-stabilizing substituent at the terminal acetylenic carbon.

Lithium arenethiolates were synthesized by the reaction of sulfur with LiC6CH4((R)-CH(Me)NMe2)-2, LiC6H3(CH2NMe2)2-2,6 and LiC6H4(CH2N(Me)CH2CH2OMe)-2 in tetrathydrofuran. The complex was isolated as adducts of tetrathydrofuran due to a strong tendency to incorporate the compound during the synthetic process. The complex is composed of two lithium atoms with a sulfur bridge between the arenethiolate ligand and the iodide atom.

A range of structural types was revealed by 6Li, 15N and 13C NMR spectroscopic investigations of (6Li,15N)lithium hexamethyldisilazide ((6Li,15N)-LiHMDS) solvated by 29 polyamines, polyethers and aminoethers. The range includes eta(super 1)-coordinated mono- and disolvated dimers, eta(super 2)-coordinated (3-coordinate) monomers, eta(super 1),eta(super 2)-coordinated (4-coordinate) monomers, eta(super 2),eta(super 2)-coordinated (5-coordinate) monomers, polymers, triple ions and solvent-separated ion pairs.

The syntheses and structural characterization of the lithium adduct ((i-Pr)2ATI)Li(THF)2 and the zirconium and hafnium complexes ((i-Pr)2ATI)2ZrCl2, ((i-Pr)2-ATI)2Zr(CH2SiMe3)2 and ((i-Pr)2ATI)2HfCl2 containing the N-isopropyl-2-(isopropylamino)troponimate ligand are described. The reaction of -isopropyl-2-(isopropylamino)troponimine ((i-Pr)2ATI)H, with n-BuLi in Et2O-THF afforded ((i-Pr)2ATI)Li(THF)2 in excellent yield. Monomeric structures in the solid state were observed in X-ray crystallography of the metal complexes.

High-resolution spectra of Mercury show no evidence of emission at the wavelength of the lithium resonance doublet, 6708 [Angstrom]. Observations were made with the 1.5-m telescope at the Catalina Observatory, near Tucson, Arizona, with the LPL echelle spectrograph and cooled CCD camera system. With an rms noise level of [approximately]0.1% we set an upper limit for the Li vertical column abundance

A variety of lithium thiolates was synthesized by ligand and donor selection to analyze their aggregation and association behaviors to several ligands. The formation of monomeric compounds was affected by the strength of the metal-chalcogen interactions which enhances solvation. Furthermore, the formation of monomeric compounds depends on the size and electronic properties of the chalcogenolate ligands. Aggregate formation is also regulated by slight changes in the ligands or donors.

A new method was developed for the synthesis of higher yields of isoindolones by adding omicron-lithiated benzoates and N-methylbenzamide to imines that are activated with BF3. The reaction of omicron-lithiobenzoates to imines with alpha hydrogens exhibited high diastereoselectivity without the presence of competing proton transfer. The reaction of isopropyl omicron-iodobenzoate with BF3.OEt2 produced 48% yield of isoindolone. The reaction was enhanced due to the faster rate of lithium-iodide exchange compared to the lithium-bromide exchange.

The synthesis of phenylglycine was utilized to design new chiral nonracemic lithium amide bases. The nonenzymatic enantioselective deprotonation of cylcohexene oxide to (S)-2-cylcohexene-1-ol by utilizing (S)-proline-based bases produced a maximum of 82% ee. The chiral base (S)-2-cyclohexene-1-ol also produced 77% ee when cyclcohexene oxide was converted to (R)-2-cyclohexene-1-ol (R)-2-cyclohexene-1-ol. The transition state model indicated the presence of larger N-substituent compared to the methyl group.

Lithium pentacyanocobaltate coordination polymers Li3(Co{CN}5).4DMF (1) and Li3(Co{CN}5).2DMF (2)(DMF = N,N-dimethylformamide) reversibly react with O2 to form 1:1 superoxo complexes. The reaction involves interaction of Li cation with nucleophilic N atoms of cyanide ligand. The interaction decreases the basicity of the cyanide ligands thereby reducing the electron density on Co(2+), thus weakening the charge-transfer interaction with O2. X-ray crystallographic analysis indicate that compound 1 cocrystallizes in triclinic space group P1. The synthesis of 1 and 2 is discussed.

A good yield of Michael adducts are formed with suitable stereoselectivity on the Michael addition of silyl enol ethers to beta-nitro and beta,beta-dicyanostyrenes in 5M lithium perchlorate/diethyl ether (LPDE) at an ambient temperature. Alpha,beta-unsaturated carbonyls are unable to undergo the Michael addition under identical conditions. The silyl group can be transferred to the Michael acceptor by using the 1 equivalent of silyl enol ether. A good yield of Benzofuran derivatives are formed by reacting silyl enol ether with p-benzoquinone in 5M LPDE.

The lithiation of 1-(benzyloxy)pyrazole with n-BuLi followed by a electrophile reaction results in the formation of 5-substituted 1-(benzyloxy)pyrazole indicating that the N(benzyloxy) group is suitable for directed metalation stabilizing of the pyrazol-5-yllithium motif. The elimination of the benzyl protecting group results in the formation of 5-substituted hydroxypyrazoles indicating that the addition of electrophiles at 5-position can be achieved by using activating the groups.

Directing metalation groups are suitable for metalation of pi-deficient heteroatomic systems namely quinolines, diazines and pyridines and because of the instability of lithium intermediates produced with pyrimidine, metalation can be achieved with in situ trapping technique. Short reaction time and excess of LTMP results in the functionalization of the parent pyridazine and pyrazine.

The agostic activation of the ortho hydrogen is an artifact of ab initio, PM3 and MNDO semiempirical methods, caused by the overestimation of the RLi...HR' interaction energies. These semiempirical techniques are suitable for studying the regioselectivities for the metalation reaction of lithium methyl-2-naphthylcarbamate.2H2O, methyl-1-naphthylcarbamate.2H2O and lithium 1,2,3,4 -tetrahydroisoquinolinecarbamate.2H2O.

We have developed a diode laser apparatus to excite Li from its ground 2S state, through 2P and 3S, to its Rydberg states with three cw diode lasers operating at [Lambda] = 671 nm, 813 nm, and 630-635 nm. A He-Ne laser at [Lambda] = 633 is sometimes used in place of the 635-nm diode laser for the last step. The output power of each of these lasers was [approximately] 1 mW. We describe our technique of locking the first two lasers on Li resonance lines by obtaining a fluorescent signal from the second decay (38 [right arrow] 2P) that is normally overpowered by a strong background of fluorescent light from the first decay (2P [right arrow] 2S). We used two balanced photodiodes to reject the strong fluorescent light without loss of collection efficiency. A rejection ratio as high as 100 has been obtained.

A new technique helps synthesize a novel sodium lithium silicate (silinaite) from dispersions of silicate in aqueous solutions of LiOH and NaOH. Various techniques including X-ray powder method and spectroscopy aid in the characterization of these layered alkali silicates. Substitution of the metal cations by protons results in the H+ form or alpha-H2Si2O5. The H+ form of silinaite and alpha-H2 Si2 O5 show similarities in structure and reactivity. Number of micropores in the H+ form of silinaite is high.

Agostic interaction parameters and proximity features evaluated by the semiempirical MNDO method efficiently predict the feasibility of the direct lithiation of monohydric and polyhydric phenolic compounds. Agostic interaction parameters indicate that peri lithiation of mono and polyhydric phenolic compounds are kinetically favored over other processes. Direct lithiations are significantly influenced by the agostic interaction, and theoretical calculations provide an evidence for the involvement of precoordinated species in lithiation reactions.

Organolithium reagents and lithium aluminum hydride induces the alkylative bridge cleavage of oxabicyclic vinyl sulfones. This method is regio- and stereospecific and produces substituted hydroxycyclohexenyl or cycloheptenyl vinyl sulfones, which have up to four contiguous chiral centers. 1H NMR and DNOE experiments examine the regio- and stereochemistry of the products.