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51.
From Linear to Angular Isomers: Achieving Tunable Charge Transport in Single‐Crystal Indolocarbazoles Through Delicate Synergetic CH/NH⋅⋅⋅π Interactions 下载免费PDF全文
Dr. Hui Jiang Dr. Peng Hu Dr. Jun Ye Dr. Apoorva Chaturvedi Dr. Keke K. Zhang Yongxin Li Dr. Yi Long Prof. Denis Fichou Prof. Christian Kloc Prof. Wenping Hu 《Angewandte Chemie (International ed. in English)》2018,57(29):8875-8880
Weak intermolecular interaction in organic semiconducting molecular crystals plays an important role in molecular packing and electronic properties. Here, four five‐ring‐fused isomers were rationally designed and synthesized to investigate the isomeric influence of linear and angular shapes in affecting their molecular packing and resultant electronic properties. Single‐crystal field‐effect transistors showed mobility order of 5,7‐ICZ (3.61 cm2 V?1 s?1) >5,11‐ICZ (0.55 cm2 V?1 s?1) >11,12‐ICZ (ca. 10?5 cm2 V?1 s?1) and 5,12‐ICZ (ca. 10?6 cm2 V?1 s?1). Theoretical calculations based on density functional theory (DFT) and polaron transport model revealed that 5,7‐ICZ can reach higher mobilities than the others thanks to relatively higher hole transfer integral that links to stronger intermolecular interaction due to the presence of multiple NH???π and CH???π(py) interactions with energy close to common NH???N hydrogen bonds, as well as overall lower hole‐vibrational coupling owing to the absence of coupling of holes to low frequency modes due to better π conjugation. 相似文献
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Summary. A novel process for the one-step chemoselective conversion of alkyl halides into carbamates as protected amines was developed
using benzyltrimethylammonium hydroxide (Triton-B) in presence of gaseous carbon dioxide. Thus, carbamate esters of different
amines were prepared in very good to excellent yields.
Present address: Institute of Organic and Biomolecular Chemistry, George–August University, 37077, G?ttingen, Germany 相似文献
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Harsh S. Shah Kaushalendra Chaturvedi Matthias Zeller Simon Bates Kenneth Morris 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(9):1213-1219
Phenytoin sodium, a salt of 5,5‐diphenylimidazolidine‐2,4‐dione, or phenytoin, is commercially available in various dosage forms for its anti‐epileptic properties to treat and prevent seizures. The title compound, poly[aquatris(μ3‐4,4‐diphenyl‐2,5‐dioxoimidazolidin‐1‐ido)trimethanoltrisodium(I)], [Na3(C15H11N2O2)3(CH4O)3(H2O)1.08]n, a methanol solvate and hydrate of phenytoin sodium, forms a modulated crystal structure that consists of a supercell made up of three close‐to‐identical repeat units. Each of the basic fragments consists of one phenytoin anion, a sodium cation, and either a methanol, or a methanol and a water molecule coordinated to the sodium ion, yielding a formula unit of Na(C15H11N2O2)(CH3OH)x(H2O)y for each of the three segments (x, y = 0 or 1; x + y = 1 or 2). Modulation along the b axis is introduced due to the presence or absence of water or methanol molecules at sodium and by the alternating torsion angles of one of the two phenytoin phenyl rings. Individual segments within the asymmetric unit are linked by covalent Na—O and Na—N bonds, with each sodium ion coordinated to one anionic amide N atom and three keto O atoms. The Na—N and one of the Na—O bonds connect (C15H11N2O2)·Na units along the modulation direction, creating an infinite [(C15H11N2O2)·Na] chain that is further stabilized by intramolecular N—H…O hydrogen bonding parallel to [010]. The second Na—O bond connects this chain with a symmetry‐equivalent copy of itself created by a screw‐axis operation, yielding double strands of [(C15H11N2O2)·Na] chains. Two of these double strands, propagating in opposite directions, constitute the content of the unit cell. Neighboring double strands are connected with each other to form layers perpendicular to the a axis, tethered together via O—H…O hydrogen bonds involving the water and methanol molecules. In addition to modulation, each of the repeat units also exhibits disorder of the modulated segments. Phenyl rings of each repeat unit are rotationally disordered, and sodium‐coordinated methanol and water molecules are also positionally disordered and/or partially occupied. The solvated structure reported here, while not matching the patterns reported for any of the known forms of phenytoin sodium, does provide a first insight into the complications and complexities involved in resolving the structure of anhydrous phenytoin sodium. 相似文献
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Devdutt Chaturvedi Nisha Mishra Virendra Mishra 《Monatshefte für Chemie / Chemical Monthly》2007,138(1):57-60
Summary. A novel Mitsunobu-based protocol was developed for the synthesis of carbamates from the corresponding alcohols using carbon dioxide and amines
in good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other reported methods. 相似文献
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Previously metal forming has been done using electromagnet in pulsed power mode, better known as magneform [1]. Here we will
be presenting a different technique for metal forming. We are using water as a medium for this process. By discharging the
stored electrical energy of the capacitor bank in water, we are getting the desired result i.e. to form (expand or compress)
a wide range of workpiece to the desired shapes. The advantage of this method over conventional method is that it uses low
power (negligible running cost). It does not require any post assembly cleaning degreasing and is hence environmentally ‘friendly’. 相似文献
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Vikas Porwal Mahendra Singh Deepika Chaturvedi Poonam Tandon Vishwambhar Dayal Gupta 《Journal of Polymer Science.Polymer Physics》2010,48(2):175-182
Poly(L ‐lactic acid) (PLLA) (? CH(CH3) ? COO? )n is a biodegradable polymer, which exhibits many applications in the biomedical field and where thermoplastics are employed. A comprehensive study of the normal modes and their dispersion in PLLA using Wilson′s GF matrix method as modified by Higgs is being reported. Assignments of calculated normal modes have been made and characteristic features of dispersion curves are discussed. Heat capacity has been calculated via density‐of‐states using Debye relation in the temperature range 10–250 K, which is in fairly good agreement with the experimental data. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 175–182, 2010 相似文献
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