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281.
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Aqueous methanolic potassium carbonate under reflux has been demonstrated to be a highly effective deprotective agent for the tert‐butyl carbamates of indoles, indazoles, carbazole, thiazoloindole, and pyrrole. The method is a mild one and is particularly expeditious for NH‐heteroarenes bearing electron‐withdrawing groups. 相似文献
284.
A novel, efficient total synthesis of a series of pterindithiolenes (15, 16, 17 and 18) [(5,6-dihydro-[1,4]dithiin or 6,7-dihydro-5H-[1,4]dithiepin systems respectively for six and seven membered dithiolenes] has been reported. The six membered quinoxaline thioketal 9 and seven membered quinoxaline dithiolene 11 have also been synthesized from quinoxaline acetylenic alcohol 5 and the corresponding acetylenic ketone 10 respectively. The synthesis of five membered pterin thioketals 12 and 13 along with the conversion of 13 to the dithiolene 14 by the reaction with NBS is also reported. 相似文献
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The rate coefficients of hydroxyl radical (OH) reaction with limonene were computed using canonical variational transition state theory with small-curvature tunnelling between 275 and 400 K. The geometries and frequencies of all the stationary points are calculated using hybrid density functional theory methods M06-2X and MPWB1K with 6-31+G(d,p), 6-311++G(d,p), and 6-311+G(2df,2p) basis sets. Both addition and abstraction channels of the title reaction were explored. The rate coefficients obtained over the temperature range of 275–400 K were used to derive the Arrhenius expressions: k(T) = 4.06×10?34 T7.07 exp[4515/T] and k(T) = 7.37×10?25 T3.9 exp[3169/T] cm3 molecule?1 s?1 at M06-2X/6-311+G(2df,2p) and MPWB1K/6-311+G(2df,2p) levels of theory, respectively. Kinetic study indicated that addition reactions are major contributors to the total reaction in the studied temperature range. The atmospheric lifetime (τ) of limonene due to its reactions with various tropospheric oxidants was calculated and concluded that limonene is lost in the atmosphere within a few hours after it is released. The ozone production potential of limonene was computed to be (14–18) ppm, which indicated that degradation of limonene would lead to a significant amount of ozone production in the troposphere. 相似文献
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Naba K. Mondal Saurabh D. Rindani Kaustubh Agashe Pankaj Agrawal B. Ananthanarayan Ketevi Assamagan Alfred Bartl Subhendu Chakrabarti Utpal Chattopadhyay Debajyoti Choudhury Eung-Jin Chun Prasanta K. Das Siba P. Das Amitava Datta Sukanta Dutta Jeff Forshaw Thomas Gajdosik Dilip K. Ghosh Rohini M. Godbole Monoranjan Guchait Partha Konar Sabine Kraml Manas Maity Kajari Mazumdar Naba K. Mondai Biswarup Mukhopadhyaya Meenakshi Narain Santosh K. Rai Sreerup Raychaudhuri Saurabh D. Rindani D. P. Roy Seema Sharma Ritesh K. Singh Rishikesh Vaidya 《Pramana》2004,63(6):1331-1353
This is a summary of the projects undertaken by the working group I on high energy and collider physics. 相似文献
289.
Gold Doping of Silver Nanoclusters: A 26‐Fold Enhancement in the Luminescence Quantum Yield 下载免费PDF全文
Giada Soldan Maha A. Aljuhani Dr. Megalamane S. Bootharaju Lina G. AbdulHalim Dr. Manas R. Parida Dr. Abdul‐Hamid Emwas Prof. Omar F. Mohammed Prof. Osman M. Bakr 《Angewandte Chemie (International ed. in English)》2016,55(19):5749-5753
A high quantum yield (QY) of photoluminescence (PL) in nanomaterials is necessary for a wide range of applications. Unfortunately, the weak PL and moderate stability of atomically precise silver nanoclusters (NCs) suppress their utility. Herein, we accomplished a ≥26‐fold PL QY enhancement of the Ag29(BDT)12(TPP)4 cluster (BDT: 1,3‐benzenedithiol; TPP: triphenylphosphine) by doping with a discrete number of Au atoms, producing Ag29?xAux(BDT)12(TPP)4, x=1–5. The Au‐doped clusters exhibit an enhanced stability and an intense red emission around 660 nm. Single‐crystal XRD, mass spectrometry, optical, and NMR spectroscopy shed light on the PL enhancement mechanism and the probable locations of the Au dopants within the cluster. 相似文献
290.
Inside Cover: Templated Atom‐Precise Galvanic Synthesis and Structure Elucidation of a [Ag24Au(SR)18]− Nanocluster (Angew. Chem. Int. Ed. 3/2016) 下载免费PDF全文