排序方式: 共有54条查询结果,搜索用时 15 毫秒
31.
Sirajud D. Khaja 《Tetrahedron letters》2010,51(33):4411-5632
Predominant α-linked products can be generated in glycosylation involving galactosyl trichloroacetimidate donors with 2-naphthylmethyl (NAP) as the non-participating group at C-2 position. The above-mentioned donor was successfully utilized for the synthesis of α-galactosyl ceramide. 相似文献
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Iwan Zimmermann Sadig Aghazada Mohammad Khaja Nazeeruddin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1084-1088
Organic‐inorganic hybrid perovskites have attracted great attention over the last few years as potential light‐harvesting materials for efficient and cost‐effective solar cells. However, the use of lead iodide in state‐of‐the‐art perovskite devices may demonstrate an obstacle for future commercialization due to toxicity of lead. Herein we report on the synthesis and characterization of low dimensional tin‐based perovskites. We found that the use of symmetrical imidazolium‐based cations such as benzimidazolium (Bn) and benzodiimidazolium (Bdi) allow the formation of 2D perovskites with relatively narrow band gaps compared to traditional ‐NH3+ amino groups, with optical band gap values of 1.81 eV and 1.79 eV for Bn2SnI4 and BdiSnI4 respectively. Furthermore, we demonstrate that the optical properties in this class of perovskites can be tuned by formation of a quasi 2D perovskite with the formula Bn2FASn2I7. Additionally, we investigate the change in band gap in the mixed Sn/Pb solid solution Bn2SnxPbx?1I4. Devices fabricated with Bn2SnI4 show promising efficiencies of around 2.3 %. 相似文献
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Juveriya Farooq Rokeya Sultana Tahreen Taj Syed Mohammed Basheeruddin Asdaq Abdulkhaliq J. Alsalman Mohammed Al Mohaini Maitham A. Al Hawaj Mehnaz Kamal Saad Alghamdi Mohd. Imran Haleema Shahin Ruheena Tabassum 《Molecules (Basel, Switzerland)》2022,27(1)
The drugs used to treat cancer not only kill fast-growing cancer cells, but also kill or slow the growth of healthy cells, causing systemic toxicities that lead to altered functioning of normal cells. Most chemotherapeutic agents have serious toxicities associated with their use, necessitating extreme caution and attention. There is a growing interest in herbal remedies because of their pharmacological activities, minimal side effects, and low cost. Thymoquinone, a major component of the volatile oil of Nigella sativa Linn, also known as black cumin or black seeds, is commonly used in Middle Eastern countries as a condiment. It is also utilized for medicinal purposes and possesses antidiabetic, anti-cancer, anti-inflammatory, hepatoprotective, anti-microbial, immunomodulatory, and antioxidant properties. This review attempts to compile the published literature demonstrating thymoquinone’s protective effect against chemotherapeutic drug-induced toxicities. 相似文献
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Muhammad Israr Nicola Pugliese Arshad Farid Shakira Ghazanfar Alessandro Di Cerbo Muhammad Muzammal Abdulhakeem S. Alamri Syed Mohammed Basheeruddin Asdaq Ashfaq Ahmad Kamran Ahmad Khan 《Molecules (Basel, Switzerland)》2022,27(10)
Controlled-release effervescent floating bilayer tablets reduce dosage frequency and improve patient compliance with enhanced therapeutic outcomes. Generally, two different tablets of clarithromycin and esomeprazole, respectively, are given for the treatment of Helicobacter pylori infection and it might be worth incorporating both in a single tablet. In the current study, controlled-release floating bilayer tablets of clarithromycin and esomeprazole (F1–F4) were developed with different rates of polymeric materials by a direct compression method. During the formulation, Fourier-transform infrared spectroscopy (FTIR) analysis was performed for possible interactions between drugs and excipients. No interactions between drugs and excipients were noted. Moreover, the bilayer tablets’ thickness, diameter, friability, hardness, weight variation, dissolution, and percent purity were found within the acceptable limits. The floating lag time and total floating time of all formulations were found to be < 25 s and 24 h, respectively. The release of both the clarithromycin and esomeprazole started at the same time from the controlled-release floating bilayer tablets by anomalous non-Fickian diffusion, and the polymeric materials extended the drug release rate up to 24 h. In the case of F1, the results approached ideal zero-order kinetics. The dissolution profiles of the tested and reference tablet formulations were compared, but no significant differences were observed. It can be concluded that such controlled-release effervescent floating bilayer tablets can be efficiently used in clinical practice to reduce dosage frequency and increase patient compliance with continuous drug release for 24 h, which ultimately might enhance therapeutic efficacy. 相似文献
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Luis A. Illicachi Javier Urieta-Mora Dr. Joaquín Calbo Dr. Juan Aragó Cansu Igci Dr. Inés García-Benito Dr. Cristina Momblona Prof. Dr. Braulio Insuasty Prof. Dr. Alejandro Ortiz Dr. Cristina Roldán-Carmona Dr. Agustín Molina-Ontoria Prof. Dr. Enrique Ortí Prof. Dr. Nazario Martín Prof. Dr. Mohammad Khaja Nazeeruddin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(48):11039-11047
Three novel donor–π-bridge–donor (D -π-D) hole-transporting materials (HTMs) featuring triazatruxene electron-donating units bridged by different 3,4-ethylenedioxythiophene (EDOT) π-conjugated linkers have been synthesized, characterized, and implemented in mesoporous perovskite solar cells (PSCs). The optoelectronic properties of the new dumbbell-shaped derivatives (DTTXs) are highly influenced by the chemical structure of the EDOT-based linker. Red-shifted absorption and emission and a stronger donor ability were observed in passing from DTTX-1 to DTTX-2 due to the extended π-conjugation. DTTX-3 featured an intramolecular charge transfer between the external triazatruxene units and the azomethine–EDOT central scaffold, resulting in a more pronounced redshift. The three new derivatives have been tested in combination with the state-of-the-art triple-cation perovskite [(FAPbI3)0.87(MAPbBr3)0.13]0.92[CsPbI3]0.08 in standard mesoporous PSCs. Remarkable power conversion efficiencies of 17.48 % and 18.30 % were measured for DTTX-1 and DTTX-2 , respectively, close to that measured for the benchmarking HTM spiro-OMeTAD (18.92 %), under 100 mA cm−2 AM 1.5G solar illumination. PSCs with DTTX-3 reached a PCE value of 12.68 %, which is attributed to the poorer film formation in comparison to DTTX-1 and DTTX-2 . These PCE values are in perfect agreement with the conductivity and hole mobility values determined for the new compounds and spiro-OMeTAD. Steady-state photoluminescence further confirmed the potential of DTTX-1 and DTTX-2 for hole-transport applications as an alternative to spiro-OMeTAD. 相似文献
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Ghosh AK Kumaragurubaran N Hong L Lei H Hussain KA Liu CF Devasamudram T Weerasena V Turner R Koelsch G Bilcer G Tang J 《Journal of the American Chemical Society》2006,128(16):5310-5311
Structure-based design, synthesis, and X-ray structure of protein-ligand complexes of memapsin 2 are described. The inhibitors are designed specifically to interact with S2- and S3-active site residues to provide selectivity over memapsin 1 and cathepsin D. Inhibitor 6 has exhibited exceedingly potent inhibitory activity against memapsin 2 and selectivity over memapsin 1 (>3800-fold) and cathepsin D (>2500-fold). A protein-ligand crystal structure revealed cooperative interactions in the S2- and S3-active sites of memapsin 2. These interactions may serve as an important guide to design selectivity over memapsin 1 and cathepsin D. 相似文献
38.
Ito S Ha NL Rothenberger G Liska P Comte P Zakeeruddin SM Péchy P Nazeeruddin MK Grätzel M 《Chemical communications (Cambridge, England)》2006,(38):4004-4006
High-efficiency flexible dye-sensitized solar cells were fabricated with a Ti-metal foil substrate for photo anode and using a Pt-electrodeposited counter electrode on ITO/polyethylene naphthalate (ITO/PEN); these devices were characterized by incident photon-to-current efficiency (IPCE), optical transmittance and electrical impedance spectroscopy. 相似文献
39.
A Computational and Experimental Study of Thieno[3,4‐b]thiophene as a Proaromatic π‐Bridge in Dye‐Sensitized Solar Cells
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George A. Puneky Dr. Amala Dass Dr. Shaik M. Zakeeruddin Prof. Mohammad Khaja Nazeeruddin Prof. Michael Grätzel Prof. Gregory S. Tschumper Prof. Jared H. Delcamp 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):694-703
Four D ‐π‐A dyes (D=donor, A=accpetor) based on a 3,4‐thienothiophene π‐bridge were synthesized for use in dye‐sensitized solar cells (DSCs). The proaromatic building block 3,4‐thienothiophene is incorporated to stabilize dye excited‐state oxidation potentials. This lowering of the excited‐state energy levels allows for deeper absorption into the NIR region with relatively low molecular weight dyes. The influence of proaromatic functionality is probed through a computational analysis of optimized bond lengths and nucleus independent chemical shifts (NICS) for both the ground‐ and excited‐ states. To avoid a necessary lowering of the TiO2 semiconductor conduction band (CB) to promote efficient dye–TiO2 electron injection, strong donor functionalities based on triaryl‐ and diarylamines are employed in the dye designs to raise both the ground‐ and excited‐state oxidation potentials of the dyes. Solubility, aggregation, and TiO2 surface protection are addressed by examining an ethylhexyl alkyl chain in comparison to a simple ethyl chain on the 3,4‐thienothiophene bridge. Power conversion efficiencies of up to 7.8 % are observed. 相似文献
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Dr. Lauren E. Polander Dr. Aswani Yella Basile F. E. Curchod Negar Ashari Astani Dr. Joël Teuscher Rosario Scopelliti Dr. Peng Gao Dr. Simon Mathew Prof. Jacques‐E. Moser Dr. Ivano Tavernelli Prof. Ursula Rothlisberger Prof. Michael Grätzel Dr. Md. Khaja Nazeeruddin Dr. Julien Frey 《Angewandte Chemie (International ed. in English)》2013,52(33):8731-8735