A tandem synthesis of N-(4-hydroxyquinolin-2-yl)sulfonamides from sulfonoketenimides and isatoic anhydride

The one-pot synthesis of a novel class of N-(4-hydroxyquinolin-2-yl)sulfonamide derivatives is achieved in moderate to good yields by the sequential copper-catalyzed reaction between sulfonyl azides, terminal alkynes, and isatoic anhydride in N,N-dimethylformamide.     

Synthesis of Functionalized N-Sulfonylamidines from N-Sulfonylketenimines and 2-Aminobenzimidazole

The synthesis of a novel class of N-(1H-benzo[d]imidazol-2-yl)-2-alkyl-N′-sulfonylacetamidines via a copper-catalyzed, three-component coupling reaction of 1H-benzo[d]imidazol-2-amine, sulfonyl azides, and terminal alkynes is described.     

Mechanistic Study on the Ozone‐Mercury Reaction and the Effect of Water and Water Dimer Molecules

The thermodynamics and mechanism of the reaction of elemental mercury with ozone has been studied computationally. The effect of water and water dimer molecules on the reaction has also been investigated. For dry reaction, we obtained two pathways and geometry optimization, atoms in molecules analysis and vibrational frequencies of all component of reaction have been used for confirming of reaction mechanism. Thermodynamic variable of reaction has been calculated. For the reaction in the presence of the water, our studies focus on ozone‐mercury complex reaction with water and water dimer and obtained the mechanism of reactions. Comparison of wet and dry reaction shows the energy profile of reaction decreases with water molecule correspond to experimental prediction. Calculated thermodynamic variable of all reaction shows the Gibbs free energy of reaction decreases with the number of water molecule.     

Al(x)Ga(1-x)N-based deep-ultraviolet 320×256 focal plane array

We report the synthesis, fabrication, and testing of a 320×256 focal plane array (FPA) of back-illuminated, solar-blind, p-i-n, Al(x)Ga(1-x)N-based detectors, fully realized within our research laboratory. We implemented a pulse atomic layer deposition technique for the metalorganic chemical vapor deposition growth of thick, high-quality, crack-free, high Al composition Al(x)Ga(1-x)N layers. The FPA is hybridized to a matching ISC 9809 readout integrated circuit and operated in a SE-IR camera system. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower, and falling off three orders of magnitude by ~285 nm. By developing an opaque masking technology, the visible response of the ROIC is significantly reduced; thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allows the FPA to achieve high external quantum efficiency (EQE); at 254 nm, average pixels showed unbiased peak responsivity of 75 mA/W, which corresponds to an EQE of ~37%. Finally, the uniformity of the FPA and imaging properties are investigated.     

Copper‐Catalyzed Synthesis of 2H‐Thiopyran Derivatives from Alkynes,Sulfonyl Azides,Carbon Disulfide,and Malononitrile

A one‐pot synthesis of functionalized thiopyran derivatives via a Cu‐catalyzed multicomponent reaction of sulfonyl azides, arylacetylenes and dipotassium 2,2‐dicyanoethylene‐1,1‐dithiolate, generated from malononitrile and CS₂, has been developed. When alkylacetylenes were used as the terminal alkynes, N‐(alkanethioyl)‐N‐(2,2‐dicyanoethanethioyl)methanesulfonamides were obtained in good yields.     

Copper‐Catalyzed One‐Pot Synthesis of N‐Sulfonylalkanimidoyl Thiocyanates from Sulfonyl Azides,Alkynes, and KSCN

Ketenimine intermediates generated by the addition of copper acetylides to sulfonyl azides are trapped by KSCN to afford N‐sulfonylalkanimidoyl thiocyanates in moderate‐to‐good yields.     

Measurements of carbon monoxide mixing ratios in Houston using a compact high-power CW DFB-QCL-based QEPAS sensor

Measurements of carbon monoxide (CO) mixing ratios in Houston, Texas, during the period from May 16, 2013 to May 28, 2013 were performed using a sensitive, selective, compact, and portable quartz-enhanced photoacoustic spectroscopy (QEPAS)-based CO sensor employing a high-power continuous wave (CW) distributed feedback quantum cascade laser (DFB-QCL). The minimum detectable CO concentration was 3 ppbv for the strong, interference-free R(6) absorption line at 2,169.2 cm^?1 and a 5 s data acquisition time. The average CO concentration during the measurement period was 299.1 ± 81.4 ppb with observed minimum and maximum values of 210.5 and 4,307.9 ppb, respectively. A commercially available electrochemical sensor was employed in-line for simultaneous measurements to confirm the response of the CW DFB-QCL-based QEPAS sensor to variations of the CO mixing ratios. Moderate agreement (R ² = 0.7) was found between both sets of CO measurements.