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The reaction of copper-mediated chlorination of phenol rings under mild conditions at room temperature which involves the ligand 1,7-bis(2-hydroxyphenyl)-2,6-diaza-4-hydroxylheptane ([H.sub.3]L1) with CuC[l.sub.2] in acetonitrile is reported.

The covalent modification of Si surfaces through a two-step chlorination-methylation method is described to introduce kinetically stable C[H.sub.3]-Si bonds onto Si(111) surfaces. The results have provided strong evidence that the energetics of chemically modified Si interfaces can be fixed with respect to pH and have shown that the band-edge energies of Si can be tuned independently of pH-derived variations in the electrochemical potential of the solution redox species.

This paper deals with the optimization of accelerated solvent extraction (ASE) for the analysis of the polychlorinated dibenzo-p-dioxins, benzo-p-furans (PCDD/Fs), mixed bromine/chlorine-dibenzo-p-dioxins, and benzo-p-furans (so-called MXDD/Fs) in solid samples. Previous theoretical studies have shown that these compounds exhibit similar electronic properties. It is reasonable to assume that there is little difference in the behavior, formation, and toxicity of PCDD/Fs and MXDD/Fs. Indeed, for most of the cases, the affinity is defined by these weak interactions. Only eight native standards are available for the MXDD/Fs; hence, the use of similar compounds (native and (13) [C.sub.12]-1abeled), such as PCDD/ Fs, is required to optimize and to validate experimental methods. This would allow conclusions to be applied for the MXDD/Fs without extended studies involving complex synthesis methods. Experimental design methodology was used to evaluate the influence of five parameters (temperature, pressure, static time, number of cycles, and solvent nature) on the polyhalogenated dibenzodioxin and -furan (PXDD/Fs) extractions in different materials. The extraction profiles and the optimal operating conditions were determined for each matrix from the modeling of extraction performance. The two following effects, the relative peak area and the co-extracted matrix (CEM), were screened in this study. The temperature of extraction was found to be the most important parameter. ASE offers automation and appears to be as efficient as Soxhlet or Soxtet; however, a major benefit was that a 4-fold decrease in extraction time was obtained. Results suggest that extraction efficiency was quantitative with extraction times as low as 15 min for all congeners at 130[degrees]C with a mixed solvent (n-hexane/acetone (1/1)). Under these operating conditions, the CEM and the degradation of the highly brominated compounds were minimized. The analysis of some real life samples from municipal solid waste incinerators showed significant amounts of PXDD/Fs.

In this paper, a Fourier transform infrared (FT-IR) spectroscopic method for detection of chlorinated aromatic compounds in soils was developed. The sensing device of this method was based on an infrared hollow waveguide, the inner surface of which was coated with a hydrophobic film. Vaporized chlorinated aromatic compounds from soils were trapped onto the hydrophobic film of the hollow waveguide sampler following detection by FT-IR spectrometry. The extraction process in this method was similar to the headspace solid-phase microextraction (HSSPME) in principle. Means of increasing the speed of transfer of the vaporized organic species to the sampler were also studied. Results indicated that, with a negative pressure on the end of the sampler, the speed of transfer increased significantly. Vapor pressures of the analytes were used as an indication to test the limitation of this method in the analysis of organic compounds in soils. Results showed that analytes with vapor pressures lower than 12 Torr could be detected quantitatively. The typical R-square of the regression on the concentration and IR signals was around 0.99 and the typical detection limits were in the range of hundreds of parts per billion.

The use of solid-phase microextraction with poly(dimethylsiloxane) (PDMS)-coated glass fibers for the extraction and analysis of hydrophobic organic analytes is increasing. The literature on this topic is characterized by large discrepancies in partition coefficients and an uncertainty of whether highly hydrophobic analytes are retained by absorption into the fiber coating or by adsorption to the fiber surface. We applied a new method, which minimizes the impact of experimental artifacts, to determine PDMS water partition coefficients of 17 hydrophobic analytes including chlorinated benzenes, PCBs, PAHs, and p,p'-DDE. These partition coefficients are several orders of magnitude higher than some reported values. Two observations strongly suggest that the retention of hydrophobic organic substances is governed by partitioning into the PDMS coating. (1) The partition coefficients are proportional with octanol/water partition coefficients. (2) The fluorescence of fluoranthene was observed to be homogeneously distributed within the polymer coating when studied by means of fluorescence microscopy. Implications of these findings for the application of solid-phase microextraction with respect to potential detection limits, with respect to biomimetic extraction, and with respect to measurements in multicompartment systems are discussed.

Iron complexes catalyze the activation of 1:1 HOOH HCl that facilitates the chlorohydroxylation of olefins and chlorination of hydrocarbons through (HCl) (L(x)FeIV(OH)Cl), an intermediate formed through a Fenton process. This intermediate, which is more reactive than HOCl, reacts with olefin substrates and saturated hydrocarbons in a highly efficient manner and in selective substrate solutions to yield chlorohydroxo and chloro derivatives.

Readily available materials with the formula R(sub f)CH2OCX double bond CYZ facilitate the synthesis of perfluorovinyl ethers. The protection of the fluorinated double bonds by chlorination is the vital reaction step. The method enables the preparation of perfluorovinyl ethers with long or short perfluoroalkyl groups. The use of perfluoro 2-butyltetrahydrofuran and hexafluoropropylene oxide oligomers as solvents reduces the chances of fragmentation.

Solvent effect highly influences the chemoselectivity of the free radical chlorination of cyclopropane. Internal pressure of the solvent is related to the ratio between ring-opened and hydrogen-abstraction products. Gas and condensed-phase chlorination of cyclopropane differ due to the solvent pressure effect of the phase. Results obtained from extrapolation techniques are in good agreement with the experimental data.

An investgation of the long-term rate and pathway dechlorination of Aroclor 1254 by sediment microorganisms from the Hudson river is discussed. Comparisons were made between polychlorinated biphenyl (PCB)-enriched and non-enriched sediments of their rate, extent and pathway of dechlorination over a 24-month period. Results indicate that highly chlorinated congeners could still be present even after the successful bioremediation of PCBs by dechlorination.

The synthesis and isolation of the elusive fullerene cage ([C.sub.2v]-[C.sub.72]) is described. The [C.sub.2v]-[C.sub.72] cage is captured by in situ chlorination to form [C.sub.72][Cl.sub.4] and the chlorination pattern and resulting stability of [C.sub.72][Cl.sub.4] are discussed.

Bicyclic C-fused chlorinated tetrahydrofuro[3,2-c]azetidin-2-ones are prepared by a general route involving Staudinger reaction of allylic/propargylic imidates with dichloroketene followed by highly diastereoselective CuCl/PMDETA-catalyzed 5-exo-trig/dig chlorine atom transfer radical cyclization. Synthetic application of the side chain chlorine atom of the products is shown by its substitution in one of the products with azide followed by azide-alkyne click reaction with phenylacetylene to obtain a 1,2,3-triazolyltetrahydrofuro[3,2-c]azetidin-2-one.

Pd[(OAc).sub.2]-catalyzed aromatic C-H chlorination is analyzed and dinuclear Pd(III) complexes are proposed as intermediated. Kinetic data obtained during catalysis and structural information of relevant intermediates is used for proposing a Pd[(II).sub.2]/Pd[(III).sub.2] catalysis cycle for Pd[(OAc).sub.2]-catalyzed aromatic C-H chlorination.

Computational methods were applied to study the mechanism of the chlorination reaction of SyrB2, a representative [alpha]-ketoglutarate dependent halogenase. CASPT2 calculations for the spin state splittings in the oxoferryl species supported the conclusion that once the [Fe.sup.IV]=O intermediate is formed, the reaction proceeds on the quintet potential energy surface.

A manganese porphyrin mediated reaction of different unactivated alkanes with sodium hypochlorite as the chlorine source was performed to obtain alkyl chlorides as major products with only trace amounts of oxygenation products. The regioselectivity and the preference for C[H.sub.2] groups in the aliphatic C-H bond chlorination could be attributed to nonbonded interactions between the alkyl groups on the substrates and the aryl groups of the manganese porphyrin.

A new [C.sub.1]-symmetric non-IPR hollow isomer, [super #23863][C.sub.78], was captured as [super #23863][C.sub.78][Cl.sub.8] and then subjected to a regioselective substitution reaction with benzyl hydroperoxide to obtain [super #23863][C.sub.78](OOC[H.sub.2][C.sub.6][H.sub.5])[Cl.sub.7]. The differences observed in in C-Cl bond length, intermediate stability, and steric effects of the involved molecules accounted for the chemical regioselectivity of the substitution reaction.

The halogenase gene prnA from pyrrolnitrin biosynthesis was introduced into Streptomyces coeruleorubidus to perform an efficient in situ chlorination of the uridyl peptide antibotic pacidamycin. The installed chlorine provided a selectably functionalizable handle enabling synthetic modification of the natural product using mild cross-coupling conditions in crude aqueous extracts of the culture broth.

Chiral short-chain [alpha]-chloroaldehydes are prepared staring from enantiomerically pure amino acids in a three-step approach, thus giving a practical synthetic alternative for known organocatalytic [alpha]-chlorination procedures. The latter aldehydes are useful starting materials for the stereoselective Staudinger synthesis of (3S,4S)-4-[(1S)-1-chloroalkyl]azetidin-2-ones in high diastereomeric ratios, which are used as chiral building blocks for preparing azetidines and pyrrolidines.

The first example of a reagent controlled organocatalytic enantioselective chloroactonization reaction is reported. Various N-chlorinated hydantoins as the terminal chlorenium source is used to cyclize several 4-aryl pentenoic acids in the presence of 0.1 equiv of [(DHQD).sub.2]PHAL.

The article discusses a new approach, which can be used for the total synthesis of the antimitotic bicyclic peptide celogentin C. The various chemical shifts taking place in the process are shown to be highly temperature and concentration dependent.

Application of [H.sub.2][O.sub.2] in conjunction with SO[Cl.sub.2] as a highly reactive reagent for the direct oxidative conversion of thiol derivatives to the corresponding sulfonyl chlorides with high purity through oxidative chlorination is described. The same reaction with amines could be used to generate corresponding sulfonamides in excellent yields within short duration of reaction times.

Several techniques are simultaneously applied to explain the characterization and synthesis of the various catena-phosphorous cations. These cations are shown to contain numerous phosphinophosphonium bonds, which are found to exhibit a strong coordinate nature.

The analysis of the J-based configuration analysis method in chlorinated hydrocarbons and chlorohydrins is described along with the development of a spectroscopic database that has facilitated the configurational assignment of these structures. Certain diastereomeric subclasses of 4,5-dichloro-2,3-epoxyhexane-1-ols have displayed a propensity to undergo ring-opening reactions at C-3 with concomitant inversion of configuration at the neighboring C-Cl at C4, implicating the intermediacy of chloronium ions.

The literature data for the partial rate factors and (ln) for [S.sub.E]Ar processes are compared to theoretical reactivity parameters to rationalize the reactivity and regioselectivity of the electrophilic chlorination, nitration, and alkylation of benzene derivatives. The observed variations of electron density at the different arene ring positions and the experimental partial rate factors for the chlorination and nitration reactions are attributed to strong steric influences on the reaction rates for substitutions involving the bulky benzyl moiety.

A four-step synthesis method is described for cis-3,5-disubstituted morpholines from enantiomerically pure amino alcohols, where the key step is a Pd-catalyzed carboamination reaction between ethanolamine derivative and an aryl or alkenyl bromide. The morpholine products are generated as single stereoisomers and this method has provided access to fused bicyclic morpholines as well as 2,3- and 2,5-disubstituted products.

The sequential treatment of optically active terminal propargylic alcohols with n-BuLi/[(HCHO).n] and regioselective chlorination has produced optically active 4-chloro-2-butyn-1-ols. The subsequent reaction of the optically active 4-chloro-2-butyn-1-ols with the corresponding Grignard reagents under the catalysis of CuCN has produced the optically active secondary 2,3-allenols.

Muironolide A, a new chemical entity with an unprecedented chlorinated hexahydro-1H-isoindolone skeleton, is isolated from the same marine sponge, Phorbas sp. that has also provided phorboxazoles A and B. Muironolide A is the first macrolide bearing an esterified trichloromethyl carbinol and is produced by a cyanobacterium that has also made phorbasides.

New 3'-terminal deoxyribonucleoside-loading reagents having a silyl-type linker are developed. A new reaction of chlorination of cytosine base is described by using 1,3-dichloro-5,5-dimethylhydantoin.

The addition of chlorine atoms to conjugated cores is shown to be general, effective route for designing n-type air-stable organic semiconductors. The calculations and cyclic voltammetry measurements in solution have shown that the chloro-functionalized molecules have a slightly smaller HOMO-LUMO gap and a lower LUMO level than the fluoro-containing molecules.

A nucleophilic multiple chlorinations of chiral epoxides that stereospecifically incorporated halogen atoms into oxygenated molecular scaffolds are used to perform synthesis of polychlorinated hydrocarbon motifs in enantiomerically pure forms. The new reagent system that form [sp.sup.3]C-Cl bonds in terms of selectivity and reactivity could be applied as the multiple chlorination method to various internal alkenyl-substituted epoxides.

The direct spectroscopic study of the catalytic hydrodechlorination of 1,1-dichloroethene in [H.sub.2]O by using surface-enhanced Raman spectroscopy (SERS) is presented. The results have provided the evidence of the room-temperature catalytic hydrochlorination of a chlorinated solvent, an important pathway for groundwater cleanup, as a sequence of dechlorination and hydrogenation steps.

A two-step chlorination/azidation process is developed for the chemical passivation of Si(111) surfaces with azide groups and the chemical and structural characterization of those surfaces are described. The [N.sub.3]-/Si(111) surface is useful for secondary functionalization through the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition and the reduction of the [N.sub.3]-/Si(111) surface using the Staudinger reduction method has produced an amine-terminated surface for the coupling of carboxylic acid molecules.

A novel, mild, and efficient method for the synthesis of C8/C9-piperazino-substituted 1,4-benzodiazepine peptidomimetic scaffolds is reported. The method based on a mild chlorination procedure applied to enantiopure amino acid chlorides could find potential use for the synthesis of small-molecule protein-protein interactions (PPI) modulators.

The synthesis of selected polychlorinated biphenyls (PCB) metabolites with differing degrees of chlorination on the oxygenated phenyl ring and their corresponding quinones is reported. The results showed that the greater number of chlorines on the (hydro)-quinone (oxygenated) ring, increased the steady-state level of the resulting semiquinone radical at near neutral pH.

Study is presented to confirm that purified KtzQ and KtzR are tandem acting halogenases that catalyze the regiospecific dichlorination of L-tryptophan to produce 6,7-dichlorotryptophan.

A two-step chlorination/Grignard process is used to develop a new method to protect silicon surfaces with C[H.sub.3]-CH=CH-MgBr organic molecules. The results provide insight into the functionalization of Si surfaces with C[H.sub.3]-CH=CH-MgBr organic molecules which nearly gives full coverage of Si atop sites, for application in molecular electronics, energy conversion, catalysis, and sensing.

Two complementary diastereo-selective substitution reactions following a highly stereoselective chlorination with sulfuryl chloride was employed to prepare 2-thiabicyclo[3.2.0]heptan-6-one-4-carboxylates with alkoxy functionality of C3. The results provide insights into the strong influence of C3 substitution on the conformational preferences of the 2-thiabicyclo[3.2.0]heptan-6-one ring system and on the rate and extent of hemiketal formation in methanol-[d.sub.4].

The effect of sodium hydroxide on the liquid phase hydrodechlorination (LPHDC) of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) over Pd/[gamma]-[Al.sub.2][O.sub.3] is evaluated. An optimum amount of sodium hydroxide is required for degrading dioxin extracts from fly ash at short reaction times to avoid poisoning and leaching of Pd and to reduce Na deposition over the active phase.

An enhanced method for the synthesis of enamine N-oxides involving aminolysis of epoxides, chlorination, N-oxidation, and dehydrochlorination is described. The results from the scope and limitations of the reaction reveal that the rearrangement of isolated [beta]-chloroamine N-oxides can be slowed by the presence of stabilizing organic acids.

Several theoretical quantum chemistry studies are conducted to explain the cation structures and vibrational frequencies of the fluorinated and chlorinated germanes and their radicals. The most stable cationic structures are found to be extremely different from their neutral counterparts.

The preparation, photophysical and anion-binding properties of a series of di-, tri-, and tetrapodal anion-binding hosts based on aminopyridium units with pyrenyl reporter groups are described. The chloride addition has resulted in an increase in the intensity of the pyrenyl monomer emission as chloride binding reduces the acceptor ability of the pyridinium groups.

The studies of the Cl, Li, and H bonds complexes with lone pair, [pi] bond, unpaired, and [sigma] bond electrons is presented. The findings reveal the first one-electron chlorine-bonded complex, [H.sub.3]C***ClF which shows an anomalous and the largest blue shift.

The investigation of the chlorination reaction of 2-phenoxypropanic acid with 1-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP) in aqueous acetic acid at pH near 0.8 is presented.

The design and synthesis of new chiral N-chloroimidodicarbonates, which has functioned as efficient chiral chlorinating agents, is presented. [C.sub.2]-symmetric (1R,2S,5R)-(-)-menthyl-N-chloroimidodicarbonate has provided good enantioselectivity for the chlorination of silyl enol ethers to afford [alpha]-chloroketones only in the presence of a suitable Lewis acid such as Sm[(OTf).sub.3].

B3LYp density functional calculations were carried out on a number of polychlorinated dibenzofurans (PCDFs) using basis sets to estimate their heats of formation. It was shown that energy contributions arising from successive chlorination can be interpreted in a predictable way based on a few important energy parameters associated with ring position and chlorine atom repulsions.