共查询到20条相似文献,搜索用时 15 毫秒
1.
Philip J. Cox Marcel Jaspars Yashodharan Kumarasamy Lutfun Nahar Satyajit D. Sarker Mohammad Shoeb 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(9):o520-o522
The crystal structure of 9‐(3‐methylbut‐2‐enyloxy)‐7H‐furo[3,2‐g]chromen‐7‐one–4‐methoxy‐9‐(3‐methylbut‐2‐enyloxy)‐7H‐furo[3,2‐g]chromen‐7‐one (0.926/0.074), 0.926C16H14O4·0.074C17H16O5, is characterized by two independent imperatorin molecules in the asymmetric unit, which exhibit different side‐chain conformations. A small amount of phellopterin overlaps with one of the two imperatorin molecules. The supramolecular structure is supported by C—H...O, C—H...π and π–π interactions. 相似文献
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Prof. Dr. Yasutomo Segawa Takehisa Maekawa Prof. Dr. Kenichiro Itami 《Angewandte Chemie (International ed. in English)》2015,54(1):66-81
Activation of aromatic C? H bonds by a transition metal catalyst has received significant attention in the synthetic chemistry community. In recent years, rapid and site‐selective extension of π‐electron systems by C–H activation has emerged as an ideal methodology for preparing organic materials with extended π‐systems. This Review focuses on recently reported π‐extending C–H activation reactions directed toward new optoelectronic conjugated materials. 相似文献
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Philip J. Cox Stephen M. MacManus 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):o603-o604
Molecules of the title compound, C13H9ClO2, contain an intramolecular O—H...O hydrogen bond, and the two aromatic rings are inclined at 57.02 (3)° with respect to one another. The crystal structure is supported by C—H...O, C—H...π and π–π interactions. 相似文献
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Kallol Mukherjee Nicolas Grimblat Somratan Sau Koushik Ghosh Majji Shankar Vincent Gandon Akhila K. Sahoo 《Chemical science》2021,12(44):14863
A direct Pd(ii)-catalyzed kinetic resolution of heteroaryl-enabled sulfoximines through an ortho-C–H alkenylation/arylation of arenes has been developed. The coordination of the sulfoximine pyridyl-motif and the chiral amino acid MPAA ligand to the Pd(ii)-catalyst controls the enantio-discriminating C(aryl)–H activation. This method provides access to a wide range of enantiomerically enriched unreacted aryl-pyridyl-sulfoximine precursors and C(aryl)–H alkenylation/arylation products in good yields with high enantioselectivity (up to >99% ee), and selectivity factor up to >200. The coordination preference of the directing group, ligand effect, geometry constraints, and the transient six-membered concerted-metalation–deprotonation species dictate the stereoselectivity; DFT studies validate this hypothesis.A Pd/MPAA catalysed KR of heteroaryl substituted sulfoximines through C–H alkenylation and arylation (up to >99% ee) is developed. In-depth DFT studies uncover the salient features. 相似文献
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David K. Geiger H. Cristina Geiger Jared M. Deck 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(12):1125-1132
The synthesis and structural characterization of 2‐(furan‐2‐yl)‐1‐(furan‐2‐ylmethyl)‐1H‐benzimidazole [C16H12N2O2, (I)], 2‐(furan‐2‐yl)‐1‐(furan‐2‐ylmethyl)‐1H‐benzimidazol‐3‐ium chloride monohydrate [C16H13N2O2+·Cl−·H2O, (II)] and the hydrobromide salt 5,6‐dimethyl‐2‐(furan‐2‐yl)‐1‐(furan‐2‐ylmethyl)‐1H‐benzimidazol‐3‐ium bromide [C18H17N2O2+·Br−, (III)] are described. Benzimidazole (I) displays two sets of aromatic interactions, each of which involves pairs of molecules in a head‐to‐tail arrangement. The first, denoted set (Ia), exhibits both intermolecular C—H...π interactions between the 2‐(furan‐2‐yl) (abbreviated as Fn) and 1‐(furan‐2‐ylmethyl) (abbreviated as MeFn) substituents, and π–π interactions involving the Fn substituents between inversion‐center‐related molecules. The second, denoted set (Ib), involves π–π interactions involving both the benzene ring (Bz) and the imidazole ring (Im) of benzimidazole. Hydrated salt (II) exhibits N—H...OH2...Cl hydrogen bonding that results in chains of molecules parallel to the a axis. There is also a head‐to‐head aromatic stacking of the protonated benzimidazole cations in which the Bz and Im rings of one molecule interact with the Im and Fn rings of adjacent molecules in the chain. Salt (III) displays N—H...Br hydrogen bonding and π–π interactions involving inversion‐center‐related benzimidazole rings in a head‐to‐tail arrangement. In all of the π–π interactions observed, the interacting moieties are shifted with respect to each other along the major molecular axis. Basis set superposition energy‐corrected (counterpoise method) interaction energies were calculated for each interaction [DFT, M06‐2X/6‐31+G(d)] employing atomic coordinates obtained in the crystallographic analyses for heavy atoms and optimized H‐atom coordinates. The calculated interaction energies are −43.0, −39.8, −48.5, and −55.0 kJ mol−1 for (Ia), (Ib), (II), and (III), respectively. For (Ia), the analysis was used to partition the interaction energies into the C—H...π and π–π components, which are 9.4 and 24.1 kJ mol−1, respectively. Energy‐minimized structures were used to determine the optimal interplanar spacing, the slip distance along the major molecular axis, and the slip distance along the minor molecular axis for 2‐(furan‐2‐yl)‐1H‐benzimidazole. 相似文献
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Dr. Junjian Miao Prof. Bo Song Prof. Yi Gao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2586-2589
The interaction between a noble gas atom and an aromatic π‐electron system, which mainly originates from the London dispersion force, is very weak and has not attracted enough attention yet. Herein, we reported a type of notably enhanced aerogen–π interaction between cation–π systems and noble gas atoms. The binding strength of a divalent cation–π system with a xenon atom is comparable to a moderate hydrogen bond (up to ca. 7 kcal mol?1), whereas krypton and argon atoms produce slightly weaker interactions. Energy‐decomposition analysis reveals that the induction interaction is responsible for the stabilization of divalent cation–π?Xe species besides the dispersion interaction. Our results might be helpful to increase the understanding of some unsolved mysteries of aerogens. 相似文献
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Veysel T. Yilmaz Canan Kazak Cumhur Kirilmis Murat Koca Frank W. Heinemann 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(7):o438-o441
The molecules of 2‐benzoyl‐1‐benzofuran, C15H10O2, (I), interact through double C—H⋯O hydrogen bonds, forming dimers that are further linked by C—H⋯O, C—H⋯π and π–π interactions, resulting in a three‐dimensional supramolecular network. The dihedral angle between the benzoyl and benzofuran fragments in (I) is 46.15 (3)°. The molecules of bis(5‐bromo‐1‐benzofuran‐2‐yl) ketone, C17H8Br2O3, (II), exhibit C2 symmetry, with the carbonyl group (C=O) lying along the twofold rotation axis, and are linked by a combination of C—H⋯O and C—H⋯π interactions and Br⋯Br contacts to form sheets. The stability of the molecular packing in 3‐mesityl‐3‐methylcyclobutyl 3‐methylnaphtho[1,2‐b]furan‐2‐yl ketone, C28H28O2, (III), arises from C—H⋯π and π–π stacking interactions. The fused naphthofuran moiety in (III) is essentially planar and makes a dihedral angle of 81.61 (3)° with the mean plane of the trimethylbenzene ring. 相似文献
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Direct arylation of imidazo[2,1‐b]thiazoles and thiazoles with aryl iodides via CuCl2/PPh3‐catalyzed C–H bond functionalization 下载免费PDF全文
With PPh3 acting as a ligand, a convenient method for CuCl2‐catalyzed arylation of imidazo[1,2‐b]thiazoles and thiazoles with aryl iodides under mild reaction conditions is described. Preliminary mechanistic studies of this arylation involving a formal Cu(I) to Cu(0) and Cu(II) route by convergent disproportionation of the copper mediator are also reported. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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《应用有机金属化学》2017,31(9)
An efficient trans ‐PdCl2(NH2CH2COOH)2‐catalyzed direct C3‐cyanation of indole C─H bonds is described. Notably, free (N─H)‐indoles reacted smoothly using the procedure, and the desired product 3‐cyanoindoles were obtained in good to excellent yields. 相似文献
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Synthesis of ent‐Ketorfanol via a C–H Alkenylation/Torquoselective 6π Electrocyclization Cascade 下载免费PDF全文
Eric M. Phillips Tehetena Mesganaw Ashay Patel Simon Duttwyler Brandon Q. Mercado Prof. Dr. Kendall N. Houk Prof. Dr. Jonathan A. Ellman 《Angewandte Chemie (International ed. in English)》2015,54(41):12044-12048
The asymmetric synthesis of ent‐ketorfanol from simple and commercially available precursors is reported. A RhI‐catalyzed intramolecular C? H alkenylation/torquoselective 6π electrocyclization cascade provides a fused bicyclic 1,2‐dihydropyridine as a key intermediate. Computational studies were performed to understand the high torquoselectivity of the key 6π electrocyclization. The computational results demonstrate that a conformational effect is responsible for the observed selectivity. The ketone functionality and final ring are introduced in a single step by a redox‐neutral acid‐catalyzed rearrangement of a vicinal diol to give the requisite carbonyl, followed by intramolecular Friedel–Crafts alkylation. 相似文献
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Hole Mobility Modulation in Single‐Crystal Metal Phthalocyanines by Changing the Metal–π/π–π Interactions 下载免费PDF全文
Dr. Hui Jiang Dr. Peng Hu Dr. Jun Ye Dr. Rakesh Ganguly Dr. Yongxin Li Dr. Yi Long Prof. Denis Fichou Prof. Wenping Hu Prof. Christian Kloc 《Angewandte Chemie (International ed. in English)》2018,57(32):10112-10117
Weak intermolecular interactions in organic semiconducting molecular crystals play an important role in determining molecular packing and electronic properties. Single crystals of metal‐free and metal phthalocyanines were synthesized to investigate how the coordination of the central metal atom affects their molecular packing and resultant electronic properties. Single‐crystal field‐effect transistors were made and showed a hole mobility order of ZnPc>MnPc>FePc>CoPc>CuPc>H2Pc>NiPc. Density functional theory (DFT) and 1D polaron transport theory reach a good agreement in reproducing the experimentally measured trend for hole mobility. Additional detail analysis at the DFT level suggests the metal atom coordination into H2Pc planes can tune the hole mobility via adjusting the intermolecular distances along the shortest axis with closest parallel π stackings. 相似文献
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Zhang‐Gao Le Yue Lu Guo‐Fang Jiang Yi‐Shuai Liu Jia Liu Zong‐Bo Xie 《Journal of heterocyclic chemistry》2019,56(11):3135-3144
α‐Chymotrypsin from the bovine pancreas has been shown for the first time to display catalytic nonnatural catalytic ability toward the C (sp3)–H functionalization reaction of 2‐methylquinoline and aromatic aldehydes in water. α‐Chymotrypsin exhibited favorable catalytic activity with good adaptability to different substrates. The activity of the enzyme could be improved by adjusting the solvent, temperature, molar ratio of substrates, and protein loading. The products were obtained in moderate to excellent yields (51%‐93%) in 24 samples. This process afforded a potential biocatalytic approach as an alternative to chemical synthesis for azaarene derivatives. 相似文献
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Rosanne C. Salmond Orde Q. Munro 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(7):m189-m193
The cation of the title complex salt, chlorido{2,2‐dimethyl‐N‐[(E)‐1‐(pyridin‐2‐yl)ethylidene]propane‐1,3‐diamine}platinum(II) tetrafluoridoborate, [PtCl(C12H19N3)]BF4, exhibits a nominally square‐planar PtII ion coordinated to a chloride ion [Pt—Cl = 2.3046 (9) Å] and three unique N‐atom types, viz. pyridine, imine and amine, of the tridentate Schiff base ligand formed by the 1:1 condensation of 1‐(pyridin‐2‐yl)ethanone and 2,2‐dimethylpropane‐1,3‐diamine. The cations are π‐stacked in inversion‐related pairs (dimers), with a mean plane separation of 3.426 Å, an intradimer Pt...Pt separation of 5.0785 (6) Å and a lateral shift of 3.676 Å. The centroid (Cg) of the pyridine ring is positioned approximately over the PtII ion of the neighbouring cation (Pt...Cg = 3.503 Å). 相似文献
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Jan Oldengott Fridolin L. B. Röhs Anja Stammler Hartmut Bögge Thorsten Glaser 《无机化学与普通化学杂志》2017,643(13):819-825
The new triplesalophen ligand H6kruseBr was synthesized as a variation of the triplesalophen ligands H6baronR by replacing a phenyl by a methyl group at the terminal ketimine in order to allow closer contacts of trinuclear complexes due to less steric hindrance by the smaller methyl group. The ligand H6kruseBr was used to synthesize the trinuclear complex [(kruseBr)NiII3], which is insoluble in organic solvents despite the coordinating solvent pyridine. Recrystallization from pyridine results in the complex [(kruseBr){Ni2(Ni(py)2)}], which was characterized by single‐crystal X‐ray diffraction. Two NiII ions are four‐coordinate by the salophen‐like subunits while the third NiII ion is six‐coordinate by two additional pyridine donors. The analysis of the molecular and crystal structure in comparison to that of NiII3 complexes of (baronR)6– reveals that the methyl group in [(kruseBr){Ni2(Ni(py)2)}] results in less ligand folding and in closer contact distance of two NiII3 complexes by π–π interactions of 3.2 Å. This indicates that trinuclear complexes of H6kruseBr are more suitable than complexes of H6baronR as molecular building blocks for the anticipated synthesis of nonanuclear single‐molecule magnets. 相似文献
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Soumen Ghosh Rupa Mukhopadhyay Madeleine Helliwell Alok K. Mukherjee 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(8):o496-o500
The pyrazine ring in two N‐substituted quinoxaline derivatives, namely (E)‐2‐(2‐methoxybenzylidene)‐1,4‐di‐p‐tosyl‐1,2,3,4‐tetrahydroquinoxaline, C30H28N2S2O5, (II), and (E)‐methyl 2‐[(1,4‐di‐p‐tosyl‐1,2,3,4‐tetrahydroquinoxalin‐2‐ylidene)methyl]benzoate, C31H28N2S2O6, (III), assumes a half‐chair conformation and is shielded by the terminal tosyl groups. In the molecular packing of the compounds, intermolecular C—H...O hydrogen bonds between centrosymmetrically related molecules generate dimeric rings, viz. R22(22) in (II) and R22(26) in (III), which are further connected through C—H...π(arene) hydrogen bonds and π–π stacking interactions into novel supramolecular frameworks. 相似文献