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A novel 3,3′-bipyrazolo[1,5-a]pyridine molecular scaffold was obtained as a product of serendipity. Both photophysical characterisations and HOMO–LUMO theoretical calculations indicate its potential as a promising fluorophore with notable intramolecular charge transfer. Nonetheless, the emission properties of this compound suffer from the typical aggregation-caused quenching effect. To overcome this situation, we introduced additional diaryl groups onto the skeleton and synthesised a series of 7,7′-diaryl-3,3′-bipyrazolo[1,5-a]pyridines via palladium-catalysed intermolecular C–H/C–H bond cross-coupling reaction in 35–62% yields. This series of tailor-made luminogens with twisted π-structures display aggregation-induced emission enhancement properties.

A facile and efficient synthetic methodology for preparing dibenzosuberones via a C-H bond activation strategy is presented. The ortho-aroylated 3,5-diarylisoxazole was employed as the starting substrate to undergo palladium-catalyzed intramolecular C-H/C-Br bond cross-coupling to produce a variety of dibenzosuberones bearing an isoxazole group in 24 to >99% 1H NMR yields. The dibenzosuberone structure was further confirmed by X-ray crystallography. The developed methodology exhibits very good functional group tolerance. In addition, a rational mechanism was presented for describing the reaction process. For the prepared dibenzosuberone, the use of Mo(CO)6 as the catalyst can easily transform the isoxazole ring into the β-aminoenone group. Finally, the structure of the anticipated ring-opening product, dibenzosuberenone, bearing a β-amino-α-ketone group was secured by X-ray crystallography.

A synthetic methodology for the late-stage ortho-C–H bond aroylation of anilines with aryl aldehydes led to a variety of ortho-aroylated anilines by the use of palladium(II) acetate, tert-butyl hydroperoxide, and 1,4-dioxane as the catalyst, oxidant, and solvent, respectively, is presented. An N-phenylpyridin-2-amine palladacycle was isolated and characterized by X-ray crystallography. Controlled experiments, radical trapping experiments, and the experiments of the kinetic isotope effect were undertaken to support the proposed reaction mechanism. Syntheses of 2-aminobenzophenone and 9(10H)-acridanone based on the developed methodology were successfully demonstrated.

Fused deposition modeling (FDM), one of the archetypal 3D printing processes, typically requires support structures matched to printed model parts that principally have undercut or overhung features. Thus, the support removal is an essential postprocessing step after the FDM process. Here, we present an efficient and rapid method to remove the support part of an FDM-manufactured product using the phenomenon of oxidative degradation of hydrogen peroxide. This mechanism was significantly effective on polyvinyl alcohol (PVA), which has been widely used as a support material in the FDM process. Compared to water, hydrogen peroxide provided a two times faster dissolution rate of the PVA material. This could be increased another two times by applying ultrasonication to the solvent. In addition to the rapidness, we confirmed that amount of the support residues removed was enhanced, which was essentially caused by the surface roughness of the FDM-fabricated part. Furthermore, we demonstrated that there was no deterioration with respect to the mechanical properties or shape geometries of the obtained 3D printed parts. Taken together, these results are expected to help enhance the productivity of FDM by reducing the postprocessing time and to allow the removal of complicated and fine support structures, thereby improving the design capability of the FDM technique.

The first example of one single crystal (NTOU-5) containing two different organic-inorganic hybrid open-framework structures was obtained using a hydro(solvo)thermal method and structurally characterized by single-crystal X-ray diffraction. Remarkably, under the same synthetic conditions, the zinc ions are respectively coordinated by oxalic acid (OX) and 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (TIMB) linkers to form two significantly different frameworks: anionic [Zn2 (OX)3 ]2- and cationic [Zn(TIMB)]2+ networks that interweave with each other to give an unprecedented interpenetrating structure with two differently-bonded open-frameworks. From the inorganic chemistry perspective, it is extremely difficult to control to which metal center the oxygen-donor linkers or/and nitrogen-donor ligands bind. A mixed Co/Zn analogue was also obtained by a similar method. The single-crystal XRD and EDS analyses indicate that the octahedral Zn ions of the anionic framework are replaced by cobalt cations, whereas the Zn ions in the tetrahedral positions of the cationic networks remain intact. This leads to the formation of the interpenetrating analogue with a mixed metal composition. Furthermore, NTOU-5 shows structural stability and efficiently removes organic dyes from aqueous solutions at concentrations of 10 ppm.

A direct arylation of pyrazolo[1,5-a]pyridines with aryl iodides selectively occurring at the C-3 and C-7 positions via palladium-catalyzed C–H activation is described. In these reactions, (a) cesium(I) fluoride and (b) silver(I) carbonate were employed as the additive to afford 3- and 7-arylated pyrazolo[1,5-a]pyridines, respectively, in modest to good yields. These reactions showed good compatibility with functional groups, and the catalytic mechanisms of these reactions were proposed. Finally, the synthetic application on the potent p38 kinase inhibitors was demonstrated.

A direct ortho aroylation of 2-phenoxypyridines with aldehydes leading to aryl ketones by the use of palladium(II) acetate, tert-butyl hydroperoxide, and chlorobenzene as the catalyst, oxidant, and solvent, respectively, is presented. Intra- and intermolecular kinetic isotope effects, radical trapping, and controlled experiments were carried out to support the proposed catalytic mechanism for the reaction. Syntheses of (2-hydroxyphenyl)(phenyl)methanones and 1-hydroxy-9H-fluoren-9-ones directed from ortho-aroylated 2-phenoxypyridines were demonstrated.

The direct ortho arylation of 4-methyl-N-phenylpyridin-2-amines via palladium(II)-catalyzed C–H activation is described. Treatment of 4-methyl-N-phenylpyridin-2-amine with potassium aryltrifluoroborate using 10 mol % of palladium(II) acetate as the catalyst, 2 equiv of copper(II) acetate as the oxidant, and 1 equiv of p-benzoquinone in tert-butyl alcohol gave ortho-arylated products in modest to excellent yields. This reaction shows good functional group compatibility. A series of 1H NMR titration experiments and controlled experiments elucidating the reaction mechanism were carried out. The key intermediate, 4-methyl-N-phenylpyridin-2-amine palladacycle, was isolated and characterized by X-ray crystallography. The advanced transformations of ortho-phenylated 4-methyl-N-phenylpyridin-2-amine to N-(4-methylpyridin-2-yl)-9H-carbazole, biphenyl-2-amine, and 3-methyl-6-phenylpyrido[1,2-a]benzimidazole were successfully demonstrated as potential synthetic applications.

Interaction between adsorbed t-butyl peroxybenzoate and photoexcited graphene rendered trapped phenyl and t-butoxy radicals. Post-irradiation thermal desorption showed benzene, t-butanol, and isobutylene oxide as the end products. The required hydrogen atoms were obtained via the radical disproportionation. Graphene enabled radical species to be captured and their on-surface chemistry to be revealed.

A one-pot synthesis of ortho-arylated 9-(pyridin-2-yl)-9H-carbazoles via C–H bond activation is presented. Silver nitrate and tert-butyl alcohol were found to be the best oxidant and solvent for the process, respectively. The product yields are from modest to excellent, and the reaction showed sufficient functional group tolerance. p-Benzoquinone served as an important ligand for the transmetalation and reductive elimination steps in the catalytic process. The key intermediate of the reaction, a 9-(pyridin-2-yl)-9H-carbazole palladacycle, was isolated, and its structure was unequivocally confirmed by X-ray crystallography. No kinetic isotope effect (kH/kD = 1.00 ± 0.17) for the C–H bond activation step was observed. In addition, a Hammett experiment gave a negative ρ value, −2.16 ± 0.02. The directing group, pyridinyl, was demonstrated to be a removable functional group. Finally, a rational catalytic mechanism is presented on the basis of all experimental evidence.

A new one-pot synthesis of 9-(pyridin-2-yl)-9H-carbazoles through the simultaneous C-H activation and palladium(II)-catalyzed cross-coupling of N-phenylpyridin-2-amines with potassium aryltrifluoroborates is presented. Silver acetate and 1,4-dioxane proved to be the best oxidant and solvent, respectively. The product yields fluctuated from modest to excellent and the reaction showed sufficient functional group tolerance. p-Benzoquinone served as an important ligand for the transmetalation and reductive elimination steps in the catalytic process. The kinetic isotope effects (k(H)/k(D)) for the first and second C-H activation/C-C or C-N formation steps were measured as 2.14 and 1.18, respectively. Finally, a rational catalytic mechanism is presented based on all experimental evidence.

Since n-type crystalline silicon films have the electric property much better than those of hydrogenated amorphous and microcrystalline silicon films, they can enhance the performance of advanced electronic devices such as solar cells and thin film transistors (TFTs). Since the formation of amorphous silicon is unavoidable in the low temperature deposition of microcrystalline silicon on a glass substrate at temperatures less than 550 degrees C in the plasma-enhanced chemical vapour deposition and hot wire chemical vapour deposition (HWCVD), crystalline silicon films have not been deposited directly on a glass substrate but fabricated by the post treatment of amorphous silicon films. In this work, by adding the HCl gas, amorphous silicon-free n-type crystalline silicon films could be deposited directly on a glass substrate by HWCVD. The resistivity of the n-type crystalline silicon film for the flow rate ratio of [HCl]/[SiH4] = 7.5 and [PH3]/[SiH4] = 0.042 was 5.31 x 10(-4) ohms cm, which is comparable to the resistivity 1.23 x 10(-3) ohms cm of films prepared by thermal annealing of amorphous silicon films. The absence of amorphous silicon in the film could be confirmed by high resolution transmission electron microscopy.

Although the deposition of crystalline silicon on a glass substrate has been pursued using hot wire chemical vapor deposition or plasma enhanced chemical vapor deposition for applications in flat panel displays and solar cells, the process has been only partly successful because of the inevitable formation of an amorphous incubation layer on a glass substrate. Currently, the crystalline silicon films are prepared by depositing an amorphous silicon film on a glass substrate and then crystallizing it by excimer laser annealing (ELA), metal induced crystallization or rapid thermal annealing (RTA). Here we report a new process, which can remove the amorphous incubation layer and thereby deposit crystalline silicon directly on glass using HCl. The intrinsic crystalline silicon film has a conductivity of 3.7×10−5 Scm−1 and the n-type doped crystalline silicon film has the Hall mobility of 15.8 cm2V−1 s−1, whose values are comparable to those prepared by ELA and RTA, respectively.

We report herein the synthesis of a fluorescence turn-on chemosensor, 25,27-bis{N-[1-(4-{[4-amino-4-(1-naphthyl)-2-oxo-3-butenyl]oxy}phenyl)aminocarbonyl]methoxy}-26,28-dihydroxycalix[4]arene (3b), which is highly selective toward Cu 2+ . The fluorescence intensity of 3b was enhanced upon adding [Cu(ClO 4 ) 2 ], which reached a maximum with approximately 4 equiv. of Cu 2+ but then started to decrease in intensity at higher Cu 2+ concentrations. Job plot experiments revealed a 1:2 binding stoichiometry of 3b with Cu 2+ . Based on 1 H NMR titration results, we infer that there are two possible binding sites for Cu 2+ in 3b: one at the lower-rim phenolic-OH and amide groups, and the second at the β-amino α,β-unsaturated ketone groups. It is important to note that during the complexation of 3b with [Cu(ClO 4 ) 2 ], the Cu 2+ ions were reduced to Cu + by both the phenolic OH and the amines of the β-amino α,β-unsaturated ketones. Furthermore, control compounds 6 and 9b were synthesized to clarify the possible binding sites of Cu 2+ in 3b. By comparing the binding constants of 3b, 6, and 9b with Cu 2+ , we found that 3b exhibited a positive allosteric behavior toward the coordination of two Cu 2+ ions.

An efficient synthesis of ortho-arylated 2-phenoxypyridines catalyzed by palladium acetate is described. Treatment of 2-phenoxypyridines with two and a half equivalents of potassium aryltrifluoroborate and 10 mol % of Pd(OAc)2 in the presence of two equivalents of Ag2CO3, one equivalent of p-benzoquinone (BQ), and four equivalents of DMSO with (or without) H2O at 130−140 °C for 48 h in dried CH2Cl2 gave the ortho-arylated 2-phenoxypyridines in modest to excellent yields. p-Benzoquinone is found to be an important ligand and co-oxidant for the transmetalation reductive elimination step in the catalytic reaction. The investigation of kinetic isotope effect (kH/kD) is determined to be 5.25, which indicates that C−H bond cleavage occurs in the rate-determining step. One of the arylated compounds, 2-(4′-nitrobiphenyl-2-yloxy)pyridine, was treated with methyl trifluoromethanesulfonate and subsequently sodium methoxide to give the 2-(4-nitrophenyl)phenol in 79% yield, demonstrating that pyridine is a removable d...

A method for stoichiometric C−H activation of 3,5-diphenylisoxazole (1) using Pd(OAc)2 as a reagent in acetic acid leading to the isoxazole palladacycle I was described. Ortho aryl- and alkyl-substituted 3,5-diphenylisoxazoles 3a−f and 5a−i were synthesized by the reaction of I with various boronic acids 2a−f and 4a−i, respectively. p-Benzoquinone was found to be the best oxidant and 1,4-dioxane the best solvent for the transmetalation−reductive-elimination step of I with boronic acids.

The direct intramolecular C—N cyclization of N-(biphenyl)pyridin-2-amines in the presence of hypervalent iodine(III) reagents is strongly influenced by substituent electronic effects.

The 1,3-dipolar cycloaddition of adamantylidenefulvene (1) with 2 equiv of nitrile oxides 2a-d gave 1/1 cycloadducts, 3a-d and 4a-d, as the major products, and four other 1/2 minor cycloadducts 5-8a,b. The ratios of 1/1 cycloadducts3a-d to 4a-d in THF solution were about 1/1 in the four different nitrile oxides 2a-d studied and microwave was found to accelerate the reactions and enhance their yields. It is noteworthy that the regioselectivity of 3a/4a was enhanced to 71/29 in b-cyclodextrin (b-CD) aqueous solution compared to that of 40/60 in the absence of b-CD. The regioselectivity of 3b/4b was further enhanced to 99/1 when 4-tert-butylphenyl hydroximinoyl chloride (9b) was complexed with b-CD and then proceeded to react with 1; this is in sharp contrast with that of 33/67 in the absence of b-CD. The binding constant of 1$b-CD in acetone-d6/D2O (1/1) was determined to be 188� 9M � 1 by 1 H NMR titration experiments. The binding mode of 1$b-CD was further determined by ROESY experiment. Furthermore, molecular dynamic simulations were carried out to provide information of the complexation modes of 1$b-CD, 3a$b-CD, 4a$b-CD, 9a$b-CD, and 9b$b-CD. It was found that both steric and electrostatic effects play important roles in determining the regio- and stereochemistry of 1,3-dipolar cycloaddition of1. Finally,b-CD is shown to serve as a chiral

Sodium borohydride reduction reactions on 4-X-adamantan-2-ones (where X=ethyleneketal 11 , ethylenethioketal 12 , and methylene 15 ) were studied, which gave Z -alcohols 16 and 17 (from en -face attack) as the predominant products for ketones 11 and 12 , but gave 1:1 mixture of Z - and E - 18 alcohols for ketone 15 . The en / zu face selectivity of 15 in sodium borohydride reduction was enhanced to 32/68 in β-CD solution. Both 1,3-dipolar addition and dichlorocarbene addition reactions on 4-ethyleneketal-2-methyleneadamantane 13 underwent again predominant en -face attack to give products in an E / Z ratio of >99:1 and 92:8, respectively. The exceptional high zu -face selectivity on the dichlorocarbene addition reaction of 15 may be explained by a temporal complexation between the carbene and the C 4 -oxo group. In the epoxidation reaction of 13 and 15 the zu -face attack products were favored despite their steric congestions suggesting that hydrogen bonding interaction between the peroxide reagent and the C 4 -oxo or 4-ethyleneketal is involved.

The hypervalent iodine(III) reagent-induced the direct intramolecular C–N cyclization of N-(biphenyl)pyridin-2-amines to 6-arylbenzimidazoles and N-pyridinyl-9H-carbazoles is presented. The substituent electronic effects governing the formation of benzimidazoles and carbazoles from the reaction of N-(biphenyl)pyridin-2-amines with hypervalent iodine(III) reagents is investigated. Radical trapping and UV–vis spectroscopic experiments on the detection of the cation radical are carried out. Rational mechanisms for these reactions are presented. The selective intramolecular C–N and C–O cyclization of N-(biphenyl)acetamides based on the substituent electronic effects is also presented.

A biscalixarene framework, without long alkyl chains, has been readily synthesized in three steps starting from the parent calix[4]arene. The biscalix[4]arene 1 was able to form organogels in various alcoholic solvents; furthermore, it exhibited an excellent phase selective gelation property that is potentially useful in oil spill recovery.

A variety of 1,2-diaryldiketones were synthesized in 15―90% yields by treatment of diarylacetylenes with Oxone as the oxidant in trifluoroacetic acid. Oxidation of 1-nitro-2-(phenylethynyl)benzene and 2,4'-(ethyne-1,2-diyl)bis(nitrobenzene) furnished 1-benzoylbenzo[c]isoxazol-3(1H)-one and benzo[c]isoxazol-3-yl(4-nitrophenyl)methanone as the major products, respectively.

A method for stoichiometric C−H activation of 3,5-diphenylisoxazole (1) using Pd(OAc)2 as a reagent in acetic acid leading to the isoxazole palladacycle I was described. Ortho aryl- and alkyl-substituted 3,5-diphenylisoxazoles 3a−f and 5a−i were synthesized by the reaction of I with various boronic acids 2a−f and 4a−i, respectively. p-Benzoquinone was found to be the best oxidant and 1,4-dioxane the best solvent for the transmetalation−reductive-elimination step of I with boronic acids.

Background/Purpose The yeast Kodamaea ohmeri rarely causes life-threatening human infections. However, risk factors, laboratory diagnoses, and treatments for K. ohmeri infection have been limited, and the optimal therapy for K. ohmeri infection has not been identified. Methods Twenty cases of K. ohmeri infection have been reported in the English medical literature. We present two new cases of K. ohmeri fungemia. We investigated the nature and treatment of K. ohmeri infections using minimum inhibitory concentrations of antifungal agents and by comparing the two cases with those described in the literature. Results From March 1998 to December 2008, a total of 22 patients with K. ohmeri infections were studied. Hematological malignancies and diabetes were the most common co-morbidities for K. ohmeri infections, with crude prevalence rates of 27.3% and 18.2%, respectively. The K. ohmeri isolates showed less susceptibility to fluconazole but greater susceptibility to amphotericin B [15/25 isolates (60%) vs. 25/25 isolates (100%), respectively]. Good outcomes (8/9 cases; 88.9%) were found following removal of indwelling catheters and implants. In addition, voriconazole and echinocandins, such as caspofungin and micafungin, also showed excellent minimum inhibitory concentrations against K. ohmeri . Conclusion K. ohmeri should not be regarded as a contaminant of blood cultures. Favorable outcomes for this potentially life-threatening infection are promoted by the removal of indwelling catheters; furthermore, outcomes are associated with optimal antifungal regimens, especially voriconazole and echinocandins.

Certain mixtures of chemicals are known to synergistically enhance skin permeability to drugs. Here, we report on the transport enhancing properties of mixtures of an anionic surfactant, sodium lauroylsarcosinate (NLS) and a non-ionic surfactant, sorbitan monolaurate (S20) in 1:1 phosphate buffered saline (PBS):ethanol (EtOH) solvent. Effect of 44 different compositions of NLS:S20 on skin constituents was probed by Fourier transform-infrared (FT-IR) spectroscopy while behavior of surfactant molecules in the solvent system was probed by FT-IR and NMR spectroscopy. No aggregation of NLS or S20 alone was observed in 1:1 PBS:EtOH at all concentrations studied (0–2%, w/v). However, mixtures of NLS and S20 resulted in micelle-like aggregates at certain specific compositions. Interestingly, compositions with increased aggregation showed resemblance to those that exhibited highest skin permeabilization.