单层2H-MoTe2光电效应的理论研究

材料的禁带宽度是影响光电探测器探测范围的重要因素.单层2H-MoTe2因具有合适的禁带宽度引起了科研人员广泛的研究兴趣.本文基于非平衡态格林函数-密度泛函理论,采用第一性原理方法,研究了单层2H-MoTe2的光电效应.结果表明:在线性偏振光照射下,MoTe2产生的光电流函数与唯象理论相吻合;在光子能量范围1.6～1.8...     

Synthesis, Structure and H+/K+-ATPase Inhibitory Activity of Novel Triazolyl Substituted Tetrahydrobenzofuran Derivatives via One-pot Three-component Click Reaction

Eleven triazolyl substituted tetrahydrobenzofuran derivatives were synthesized in high yields as novel H⁺/K⁺‐ATPase inhibitor via one‐pot CuI‐catalyzed three‐component click reaction of azide, secondary amine and 3‐bromopropyne under mild conditions in water. Their structures were characterized by NMR, IR, ESI‐MS, elemental analysis and single‐crystal X‐ray diffraction analysis. Most of the target compounds exhibited better H⁺/K⁺‐ATPase inhibitory activity than commercial omeprazole with IC₅₀ values less than 15 µmol·L^?1. The initial structure‐activity analysis suggested that the triazole substituted by cycloalkyl, aromatic ring or O‐containing side‐chain seemed to be beneficial for enhancing the activity.     

A modified procedure for synthesis of the side chain of ceftazidime-activated thioester

A modified procedure for synthesis of the side chain of ceftazidime-activated thioester has been established. This key intermediate of ceftazidime was obtained by a more eco-friendly process than conventional methods, and the yield was much higher (up to 92.4 %). It was found that different organic bases (triethylamine or pyridine) used in this reaction had different effects. The reaction conditions were also optimized to make the route more competitive and suitable for large-scale industrial production.     

Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides

We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ionic nature in different systems, the Mn-L spectra fingerprint the Mn valence and spin states through spectral lineshape and energy position consistently and evidently. The clear O- and F-K pre-edge features in our high resolution spectra enable a quantitative definition of the molecular orbital diagram with different Mn valence. In addition, while the binding energy difference of the O-1s core electrons leads to a small shift of the O-K leading edges between trivalent and quadrivalent manganese oxides, a significant edge shift, with an order of magnitude larger in energy, was found between divalent and trivalent compounds, which is attributed to the spin exchange stabilization of half-filled 3d system. This shift is much enhanced in the ionic fluoride system. This work provides the spectroscopic foundation for further studies of complicated Mn compounds.     

Multireference calculations on low-lying states and the X~3 Π_u -~3 Π_g absorption spectra of indium dimers

Multireference configuration interaction calculations are carried out on 11 Λ-S low-lying electronic states of indium dimers. The states are investigated with spin-orbit pseudopotentials via the state-interacting method, and characterized by fitted spectroscopic constants based on computed potential energy curves. The vibrational structures of the double-potential well 0+g (I) ( 3 Σ g ) state are also analyzed. The experimentally observed absorption spectrum centred at ～ 13000cm-1 is simulated and assigned to X 3 Πu (v=0)-3Πg transition according to the present ab initio calculations on transition energies and dipole moment functions.     

Development of Sn2+-based oxyfluoride photocatalyst with visible light response of ca.650 nm via strengthened hybridization of Sn 5s and 02p orbitals

The hybridization between the outmost s orbitals of metal (Bi3+,Sn2+,Pb2+,Ag+) and O 2p orbitals has been widely employed to develop innovative semiconductors w...     

Substrate-controlled and highly stereoselective synthesis of 2-aminobut-2-ene-1, 4-diones

2-Methylthio-substituted 1,4-enediones, obtained from readily available aryl methyl ketones, were reacted with primary or secondary amines to afford the desired 1,4-diaryl-2-aminobut-2-ene-1,4-diones in excellent yields with high Z/E-stereoselectivity.     

An environmentally benign benzylic oxidation catalyzed by hypervalent iodine intermediate in water

An effective and environmentally benign benzylic oxidation for transition of alkylarenes into the corresponding carbonyl compounds was reported.Alkylarenes were mixed and stirred with potassium bromide,m-chloroperbenzoic acid and a catalytic amount of iodobenzene in water at 60 8C for several hours,a series of the corresponding carbonyl compounds was obtained in moderate to good yields.In the reaction,iodobenzene was first oxidized by m-chloroperbenzoic acid into the hypervalent iodine intermediate which then reacted with potassium bromide to form the key radical initiator for the benzylic oxidation.