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Thioimidates 1-Z undergo facile cross-coupling with Pd(0)-RZnI but are inert to Pd(0)-[R.sub.2]Zn. This difference is due to the lower Lewis acidity of [R.sub.2]Zn, as opposed to lower nucleophilicity. Various sources of RZnI (R = Me, Et) and Pd(0) were evaluated for their convenience and reactivity. Key words: thioimidates, cross-coupling, dialkylzincs, alkylzinc iodides.

Treatment of the oligomeric compound [[Cp*Sc[Cl.sub.2]].sub.n] (Cp* = [C.sub.5][Me.sub.5]) with tri-tert-butylphosphine oxide in THF leads to the monocyclopentadienyl scandium dichloride [Cp*(t-[Bu.sub.3]P=O)Sc[Cl.sub.2]] as a monomeric, THF-free solid in 72% yield. This compound can be alkylated with MeLi to give the corresponding dimethyl derivative, [Cp*(t-[Bu.sub.3]P=O)Sc[Me.sub.2]], 1. The crystal structures of these two compounds have been done and reveal a three-legged piano stool geometry about the scandium center. The coordinated phosphine oxide ligand exchanges with free donor in both compounds via an associative mechanism, as indicated by the activation parameters ([DELTA]H[double dagger] = 6.4-8.4 kcal [mol.sup.-1]; [DELTA]S[double dagger] = -22.5 to -26.6 eu). Thus, the Cp*(t-[Bu.sub.3]P=O) ligand set provides a stable platform for organoscandium chemistry. This was demonstrated by the activation of 1 by treatment with [B([C.sub.6][F.sub.5]).sub.3] to form the fully characterized contact ion pair [[Cp*(t-[Bu.sub.3]P=O)ScMe].sup.+][MeB[([C.sup.6][F.sub.5]).sub.3]].sup.-], 2, which is an active ethylene polymerization catalyst. Key words: organoscandium compounds, olefin polymerization, cationic complexes.

Results demonstrate that (sup)57Fe Mossbauer isomer shifts can be accurately predicted for inorganic, organometallic, and metalloporphyrin/metalloprotein model systems at different spin states using density functional theory calculations. Data indicate that this methodology is superior to that of Hartree-Fock method.

Results reveal that four precursors of dimethylstannylene which absorb in the region of 450-520 nanometers. Based on the gaseous product analyses, the absorptions can be attributed to dimethylstannylenes, the first report for any organo-stannylene. Data indicate that the compound does not react with alkenes but reacts with dienes or alkynes.

A complete methodology for the preparation and characterization of ferrocenoyl-dipeptides along with their X-ray structures are presented. The interaction of the ferrocenoyl-dipeptides with 3-aminopyrazole derivatives in solution is discussed. Furthermore, electrochemical analysis of the interaction between the ferrocenoyl-dipeptides and the aminopyrazole ligands are described.

The boratabenzene complex di-mu-chlorotetrakis(1-methylboratabenzene)diyttrium crystallizes into three conformationally different polymorphs, which differ in the relative orientations of the boratabenzene ligands. The intra- and inter- molecular geometry and crystal packing features of the polymorphs are presented in terms of quantum chemical and lattice energy calculations.

Salen-group 13 ligands are derived by combining a diamine with 2 equivalents of salicyclaldehyde and are ideal for the equatorial coordination of transition metals and catalysis. The use of group 13 compounds is generally in combination with Salen-supported trnsition metal compounds.

Research demonstrates the synthesis of alcohol complexes of osmium nitrosyl porphyrins for the first time. Data reveal that these heme-containing biomolecules undergo facile deprotonation mediated by pyridine to yield cognate alkoxide derivatives.

Research demonstrates that low molecular weight organic compounds can be prepared from functionalized carbosilane dendrimers used as soluble supports. The methodology employs enolate-imine condensation and dendritic species that have only one functional group per peripheral Si-site.

A highly selective optical sensor for chloride, based on the multidentate Lewis acid ionophore [9]mercuracarborand-3, is described herein. This sensor is constructed by embedding the mercuracarborand ionophore, a suitable pH-sensitive lipophilic dye, and lipophilic cationic sites in a plasticized polymeric membrane. The multiple complementary interactions offered by the preorganized complexing cavity of [9]mercuracarborand-3 is shown to control the anion selectivity pattern of the optical film. The film exhibits a significantly enhanced selectivity for chloride over a variety of lipophilic anions such as perchlorate, nitrate, salicylate, and thiocyanate. Furthermore, the optical selectivity coefficients obtained for chloride over other biologically relevant anions are shown to meet the selectivity requirements for the determination of chloride in physiological fluids, unlike previously reported chloride optical sensors. In addition, the optical film responds to chloride reversibly over a wide dynamic range (16 (mu)M - 136 mM) with fast response and recovery times.

Results demonstrate the synthesis of phosphonate anions of aluminum-fluorine complex and fluoroalkoxy bridged derivative of titanium using n-Bu(sub)4NHF(sub)2 as a fluorinating agent. Data show characterization of these fluorinated metal alkoxides compounds by spectroscopic and X-ray diffraction techniques.

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 describes the synthesis of porphyrazinediols, their conversion into solitaire complexes, and chemical oxidation of the polydentate noninnocent macrocycles. Results demonstrate that porphyrazinediols are a novel class of redox-active ligands whose diol chelating group is directly attached at the beta-positions of the macrocycle.

Research has been conducted on the reactions of iodoperfluoro-3-oxaundecylsulfonyl fluoride with Cu, Zn or Grignard reagent. The production of organometallic species that further reacted with halohydrocarbons is described.

Results demonstrate that nonlinear optical measurements of organometllic compounds exhibit real cubic hyperpolarizability. Data also show that third harmonic generation responses can be inferred from hyperpolarizability and susceptibility data measured in solutions and films respectively.

Research has been conducted on the water substitution in the half-sandwich complexes by Cl (super)-, Br (super)-, I (super)-, nicotinamide, pyridine, thiourea and dimethylsulfide. The use of the stopped-flow spectroscopy is described.

A study on electron transfer processes at the interface between two immiscible electrolyte solutions identified the origin of the apparent potential dependence of the electron transfer rate by measuring the kinetics of the reverse electron transfer reaction. Scanning electrochemical microscopic techniques were used in the study. The ultramicroelectrode tip was positioned in the aqueous phase containing Ru(CN)6-4 and approached the organic layer containing ZnPor. Findings are discussed.

A study investigated the mechanism of reversible dioxygen binding to hemerythrin using density functional calculations to interpolate between experimentally calibrated bonding descriptions of oxyhemerythrin and deoxyhemerythrin that were derived in a previous study. Findings furnish new significant insights into the nature of the one-electron transfer mechanisms, the sequence where the one-electron transfer and proton transfer events occur, the correlation of spin states and the role of antiferromagnetic exchange coupling through the bridging oxide in one-electron transfer.

The role of water in the synthesis of aquo organometallic complexes were observed. Analysis shows that water's strong coordinating power and the extra stability of hydrogen bonds' net with bulk water enable the aquo organometallic complexes to be inert. The two factors were found to be instrumental in preventing the creation of vacant sites. The complete sequence of fundamental reactions needed for olefin activation were documented.

A series of organometallic salts made up of fac-(b)ReI(CO)3(py)(super +) cation and a Co(CO)(sub 4)(super -) anion have been synthesized and their crystal structures and photophysical properties studied. The b = 4,4',5,5'-tetramethyl-2,2'-bipyridine (tmb), 2,2'-bipyridine (bpy), 4,4'-dicarbomethoxy-2,2'-bipyridine (dmeb) and py = pyridine. The photoinduced electron transfer of these salts has been investigated to gain an insight on the control charge recombination and case escape in transition metal complexes.

Four organometallic complexes of Eu3+ have been synthesized in Y, mordenite and ZSM-5 zeolites by adsorbing the ligand into the Eu3+-doped zeolites. These compounds will be used in studying how their luminescence is affected by the Eu3+ content, the nature of the ligand and the zeolite crystalline structure. Results show that the complexes exhibit longer lived emissions even when the highest ligand:metal stoichiometry cannot be achieved. The emission is 10-fold longer than those for complexes in solution.

The crystal structure of four organosilver(I) complexes of polycyclic aromatic hydrocarbons has been investigated. The study sought to find out if organometallic solid materials with unique bonds can be synthesized from cation-pi interactions and aromatic stackings. Metal ions joined by pi macrocycles such as 9,10-diphenylanthracene, rubrene, benzopyrene and coronene have been examined. Results show that pi macrocycles and pi-pi stackings can be used to synthesize new supramolecules with possible electric properties.

Two new methods for the simultaneous identification and quantification of organotin compounds (OTs) including monobutyltin, dibutyltin, tributyltin, monophenyltin, diphenyltin, triphenyltin, and tricyclohexyltin (TCyT) in natural waters and sediments, respectively, are presented. For water samples, aqueous ethylation followed by liquid-liquid extraction (LLE) or solid-phase extraction and large-volume-injection GC/MS (50-200 [[micro]liter]) were used. For sediment samples, accelerated solvent extraction at 100 [degrees] C with a methanolic mixture of sodium acetate and acetic acid was developed. By using for the first time perdeuterated OTs as internal standards, excellent precision (relative standard deviations

The molecular and crystal structures of organometallic complexes exhibiting the intermolecular interactions of metal-hydride (M-H) were analyzed. The intermolecular reactions of M-H---H-M and M-H---H-C types were determined through the combination of extended Huckel and density functional calculations. The obtained evidence showed the amphoteric behavior of the M-H bond. The M-H---H-M bonding was considered as the supramolecular equivalent of the covalent bond while the M-H---H-C bonds were the equivalent of a polarized bond linking atoms of different electronegativity.

The selectivity and reactivity of nucleophilic additions of various organometallic reagents to the free C=N bond of imines, hydrazones, oximes and nitrones have significantly improved. The scope of such reactions have greatly benefited from the use of organocerium and organocopper reagents. The addition of organometallic reagents have also improved techniques associated with the obtention of enantiomerically-enhanced amines and amino derivatives.

Organometallic crystal engineering supports an organic outlook of crystal engineering. Its scope focuses on the characterization of molecular crystals for a range of physical and chemical applications. A number of factors are considered critical in the crystal engineering of organomettalic compounds. These factors are correlated with the location of the metal centers in the compounds within the molecular cores. The features of organometallic molecules support dependencies related to the relationship between the electronic nature of the metals and the intermolecular bonding of ligands.

Research was conducted to isolate and characterize cyclopenta[l]phenanthrene (dibenz[e,g]indene) with isodibenzindene using x-ray crystallography and nuclear magnetic resonance spectroscopy. This compound is trapped in situ by its precursor cyclopenta[l]phenanthrene. Results using the Diels-Alder dimerization confirm RHF/3-21G calculations regarding the relative stability of the isoindene.

The organometallic compound vinylene-Co,N-linked multi(porphyrin)s, (Por)CoIII-CH=CH-(N-Por)H2 was a product of the nucleophilic addition reaction of a pyrrole nitrogen of free-base porphyrins to a phi-complexed acetylene ligand. The formation of such compound was also influenced by the CoIII porphyrin intermediate. Such cobalt complexes underwent oxidative migration for the Co-bound vinyl group to a porphyrin pyrrole nitrogen.

Low-pressure metalorganic chemical vapor deposition was used to create AlGaInP/GaInP visible strained quantum well lasers. A visible laser diode developed through AlInP cladding layer features a threshold current of 30 mA and an output of at least 32 mW under continuous wave operation at room temperature. Test results indicate the possibility of reducing transverse beam divergence at low threshold current.

The extraction equilibrium of U(VI) between a nitric acid solution and a supercritical C[O.sub.2] phase containing tributyl phosphate (TBP) is formulated taking into account that (i) a distribution ratio of a metal extracted is a function of a distribution constant of each component involved in the extraction reaction, (ii) the distribution constant is defined as a ratio of solubilities of the component in both phases, and (iii) the solubility in the C[O.sub.2] phase is correlated with density of C[O.sub.2]. A simple linear relationship between the distribution ratio, [D.sub.U], of U(VI) and density, [Rho], of C[O.sub.2] is derived; log [D.sub.U] = a log [Rho] + A + B, in which a is a proportional constant implying the solvation characteristic of the solute in supercritical C[O.sub.2], A is a pressure-independent constant, and B is a variable determined by the distribution equilibrium of HN[O.sub.3]. The equation derived was verified experimentally by the measurement of the distribution ratio of U(VI) and HN[O.sub.3] under various conditions of pressure and temperature. A novel concept of selective supercritical fluid extraction of metals by means of pressure-tuning or C[O.sub.2] density-tuning was proposed.

An analysis was conducted to characterize the compound niobium oxo acetate and determine its process of synthesis and X-ray crystal structure. The nuclear magnetic resonance spectroscopy was utilized in the compound's solid and liquid states. Results revealed that cluster structure of the compound is fully preserved in solution making the cluster a building blocks for the synthesis of sol-gel derived materials.

A series of anion-exchange materials were prepared by adsorption of the dark-green organometallic salt [HEP.sup.+][N[O.sub.3].sup.-] or [HEP.sup.+][Re[O.sub.4].sup.-] dissolved in organic solvents onto three different silica gels (HEP = 1, 1[prime],3,3[prime]-tetrakis(2-methyl-2-hexyl)ferrocene). Adsorption isotherms showed that the amount of [HEP.sup.+] salt adsorbed depended on the choice of counteranion, solvent, surface area, and pore size diameter of the silica gel. After drying the [HEP.sup.+][N[O.sub.3].sup.-]/Si[O.sub.2] and [HEP.sup.+][Re[O.sub.4].sup.-]/Si[O.sub.2] solid materials, the organometallic salts did not desorb into the aqueous phase when the solids were treated with aqueous solutions containing NaN[O.sub.3] and/or HN[O.sub.3]. The [HEP.sup.+][N[O.sub.3].sup.-]/Si[O.sub.2] materials functioned as redox-recyclable ion exchangers. Treatment of the materials with aqueous waste simulants containing KRe[O.sub.4], NaN[O.sub.3], and HN[O.sub.3] resulted in [N[O.sub.3].sup.-]/[Re[O.sub.4].sup.-] ion exchange as follows: [Mathematical Expression Omitted]. The distribution coefficient for one of the new materials was 100 mL/g (440 mL/mmol of [HEP.sup.+]) for an aqueous waste simulant containing [Re[O.sub.4].sup.-] and 1.0 M HN[O.sub.3]. This can be compared with 290 mL/g (87 mL/mmol of cationic sites) for Reillex-HPQ, a commercial non-redox-recyclable ion-exchange resin which has been studied for [Re[O.sub.4].sup.-] and [Tc[O.sub.4].sup.-] extraction. The higher distribution coefficient per millimole of cationic sites suggests that [HEP.sup.+][N[O.sub.3].sup.-]/Si[O.sub.2] is more selective for [Re[O.sub.4].sup.-] than Reillex-HPQ under these conditions. The recovery of adsorbed [Re[O.sub.4].sup.-] was accomplished by treating the exchanged materials with aqueous ferrocyanide, which caused the reduction of adsorbed HEP- to adsorbed HEP and concomitant release of the adsorbed counterions [Re[O.sub.4].sup.-] and [N[O.sub.3].sup.-]. Reactivation of HEP/Si[O.sub.2] to [HEP.sup.+][N[O.sub.3].sup.-]/Si[O.sub.2] was accomplished with aqueous ferric nitrate. Five complete extraction - deactivation/([Re[O.sub.4].sup.-] recovery) - reactivation cycles (duty cycle time 94 min) consistently showed a slow decrease in distribution coefficient ([approximately]20% over five cycles). Nevertheless, the data indicate that redox-recyclable anion exchange is a viable concept and that redox-recyclable ion-exchange materials with improved stability should be considered as viable alternatives to traditional anion-exchange resins in the future.

The regiochemistry of the addition of alkyl cuprates to chiral silabromoallenes is dependent on the presence of the silicon nucleus of silylated bromoallenes. Polysubstituted chiral silaalkylallenes were formed by the stereospecific substitution of the silylated bromoallenes which also involves a formal bromine SN2 nucleophilic substitution of the sp2 carbon. A propragylic Cu(III) intermediate was also formed during the initial reactions due to the displacement of the bromine by nucleophilic copper.

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.

Trisubstituted fluoroalkenes were synthesized by the reaction of organolithium reagents to trifluoromethyl enol ethers and thio enol ethers. The course of the reaction of nonterminal CF3-substituted vinylic compounds with organolithium reagents reagents is strongly dependent on the substitution pattern. The formation of E-trisubstituted fluoroolefins also involved the instantaneous stereoselective elimination of lithium ethoxide/thioethoxide.

The reaction of Bu3SnLi with gamma-OTBS crotonaldehyde led to the synthesis of alpha, delta-dioxygenated allylic stannanes which reacted with MOM-Cl or TBS-Cl to produce alpha-oxygenated allylic stannane. The alpha, delta-dioxygenated crotylstannanes were affected by the type of reagent that reacted with delta-dioxygenated allylic stannane. Furthermore, the differing selectivities of the MOM and TBS indium reagents were caused by interactions between the ethol ether substituent and the aldehyde substituent.

The morphology of copper films deposited from metalorganic precursor bis(t-butylacetoacetato)Cu(II) was examined using scanning tunneling microscope. The nanostructure of the film was investigated to determine its correlation with the resistivity and the temperature dependence of the resistivity. The results established the dependence of the growth conditions on the nanostructure of the metalorganic chemical vapor deposition films.

The role of ferric chloride hexahydrate as a mild hydrolytic agent for the deprotection of acetal was investigated through utilization of an increasing equivalents of FeCl3*6H2O in a deprotection study. The resulting quantitative deprotection of the 1,3-dioxane of cinnamaldehyde revealed that FeCl3*6H2O hydrolyzed the dioxane functionality effectively. It was also found that FeCl3*6H2O decreased the reactivity of dioxolane towards olefin isomerization.

Neutral PtRu2C(CO) complexes were utilized as molecular cluster precursors for the synthesis of carbon-supported Pt-Ru nanoparticles. The formation of the bimetallic particles was dependent on the activation of the cluster precursors on the carbon support via narrow compositional and size distributions. Analysis of the resulting carbon-supported Pt-Ru nanoparticles via X-ray absorption fine structure spectroscopy also indicated the presence of a face-centered cubic packing structure.

The process of yielding a tetrameric [{Cu(OC6H3Ph2)(CO)]2] dimer from carbonylation of 2,6-dphenylphenoxocopper(I), tetrameric [(CuOC6H3Ph2)4] was described. The parent compound, aryl oxide, resulted to a mu2-phenoxo bridged dimer comprising of a three-coordinated copper(I) with longer copper-oxide bonds. It was indicated that the Cu-C bond was classified to have a sigma character.

1H nuclear magnetic resonance titration method was utilized to examine the selective binding constants for Sc3+, Lu3+, Y3+, and La3+. It was shown that the binding of a metal ion was initially mediated by an alcoholysis reaction between the macrocycle and metal ion resulting in the formation of a M(H2L)X2 complex. A sheet structure with solvent byproduct was formed using AgCF3-SO3 in benzene. It was also indicated that the counterions had a direct effect on the coordination network topology.

High-resolution Shpol'skii spectroscopy was utilized to investigate the intraligand charge transfer in Pt(qol)(sub 2). Intraligand charge transfer transitionsn were found to generate low-lying singlet and triplet states. It was found that the phosphorescence decays triexponentially with the components polarization as evidenced by the biexponential decay. Spectral findings revealed highly resolved vibrational satellite structures.

The capabilities of alpha-thia and alpha-amino aldehydes to mediate the reaction of 1,2-asymmetric induction during allyndation was probed using water as the solvent. It was shown that the allyndium reagent has no thiophilic properties based on the reactivity of the SPh and SCH3 derivatives. Furthermore, the N-acetylmannosamine was found to be very reactive to chelation control based on the sensitivity of their asymmetric induction shifts towards the syn direction.

The half-lives of transient complexes with metal-carbon sigma-bonds which decompose homolytically decreased in the presence of NO. The effects of NO on the half-lives of the transient complexes were due to two alternative competing mechanisms involving the reaction of NO with the carbon-centered radical and the transient complex. The rate constants of the CH3 and CH2OH were slower compared to NO due to steric interactions.

Single-crystal diffraction techniques were utilized to study the trans-diaquabis(methoxyacetato)copper(II). Single-crystal diffraction of thetrans-diaquabis(methoxyacetato)copper(II) with temperatures above 325 degrees kelvin indicated the ability of the Cu2O2O2'O2'' chromophore to changes smoothly from an elongated rhombic octahedron at the lowest temperatures to a compressed rhombic octahedron at the highest temperatures. The main symmetry axis also changes from MeO-Cu-OMe to H2O-Cu-OH2.

The photoinduced reactions of (t-Bu)3In with Et2NSnMe3 and (n-Bu)2NSnMe3 led to the formation of [(t-Bu)2InNEt2] and [(t-Bu)2InN(n-Bu)2], respectively, with typical yields of 75-85%. Crystallographic analysis of the resulting compounds that were formed via alkyltrimethyltin elimination reactions indicated the presence of similar molecular bond lengths and bond angles. Furthermore, the average In-C bond length of the compounds were longer than the average bond length of [(t-Bu)2InN(n-Bu)2]2.

A novel method for the enantiomeric enrichment of allenedicarboxylates was developed based on the complexation of the starting compound with (+)-Eu(hfc)3. The synthetic process was characterized by the introconversion of diastereoisomeric complexes and subsequent enrichment of the preferred compound with the europium reagent. The synthetic process also involved the reconstruction or reordering of the higher-order complex in the reaction solution.

A novel method for the synthesis of a series of 4,6-dideoxypyranoside derivatives was developed based on the utilization of (TMM)Fe(CO)3 complexes [(TMM) = trimethylenemethane]. The synthetic strategy was characterized by the reaction of a racemic compound with 1-methoxy-3-[(trimethoxylsilyl)oxy] -1,3-butadiene in BF3.Et2O. The resulting intermediate product was reacted with trifluoroacetic acid to form single diastereoisomers of the dihydropyrone complex.

A novel method for the synthesis of alpha-aminocarbanions was developed based on the conversion of N-(alpha-aminoalkyl)benzotriazoles in Li/LiBr-mediated reactions. The synthetic strategy was characterized by the reaction of N-(alpha-aminoalkyl)benzotriazoles with Li/LiBr or SmI2 in the presence of representative electrophiles to generate nonstabilized alpha-aminocarbanions. Furthermore, the main byproduct of the reaction is a weak acid that can be easily washed away by utilizing a basic aqueous solution.