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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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Dr. Kaori Fujisawa Dr. César Beuchat Marie Humbert‐Droz Dr. Adam Wilson Prof. Tomasz A. Wesolowski Dr. Jiri Mareda Dr. Naomi Sakai Prof. Stefan Matile 《Angewandte Chemie (International ed. in English)》2014,53(42):11266-11269
Herein, we address the question whether anion–π and cation–π interactions can take place simultaneously on the same aromatic surface. Covalently positioned carboxylate–guanidinium pairs on the surface of 4‐amino‐1,8‐naphthalimides are used as an example to explore push–pull chromophores as privileged platforms for such “ion pair–π” interactions. In antiparallel orientation with respect to the push–pull dipole, a bathochromic effect is observed. A red shift of 41 nm found in the least polar solvent is in good agreement with the 70 nm expected from theoretical calculations of ground and excited states. Decreasing shifts with solvent polarity, protonation, aggregation, and parallel carboxylate–guanidinium pairs imply that the intramolecular Stark effect from antiparallel ion pair–π interactions exceeds solvatochromic effects by far. Theoretical studies indicate that carboxylate–guanidinium pairs can also interact with the surfaces of π‐acidic naphthalenediimides and π‐basic pyrenes. 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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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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Dr. Koji Yamamoto Seita Kimura Prof. Tetsuro Murahashi 《Angewandte Chemie (International ed. in English)》2016,55(17):5322-5326
The intrinsic features of (hetero‐arene)–metal interactions have been elusive mainly because the systematic structure analysis of non‐anchored hetero‐arene–metal complexes has been hampered by their labile nature. We report successful isolation and systematic structure analysis of a series of non‐anchored indole–palladium(II) complexes. It was revealed that there is a σ–π continuum for the indole–metal interaction, while it has been thought that the dominant coordination mode of indole to a metal center is the Wheland‐intermediate‐type σ‐mode in light of the seemingly strong electron‐donating ability of indole. Several factors which affect the σ‐ or π‐character of indole–metal interactions are discussed. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7315-7318
A series of N ‐arylimide molecular balances were designed to study and measure fluorine–aromatic (F–π) interactions. Fluorine substituents gave rise to increasingly more stabilizing interactions with more electron‐deficient aromatic surfaces. The attractive F–π interaction is electrostatically driven and is stronger than other halogen–π interactions. 相似文献
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Dr. Seth E. Snyder Bin‐Syuan Huang Yu W. Chu Huei‐Shian Lin Prof. Dr. James R. Carey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12663-12671
We have designed and utilized a simple molecular recognition system to study the substituent effects in aromatic interactions. Recently, we showed that 3‐ and 3,5‐disubstituted benzoyl leucine diethyl amides with aromatic rings of varying electronic character organized into homochiral dimers in the solid state through a parallel displaced π–π interaction and two hydrogen bonds, but no such homochiral dimerization was observed for the unsubstituted case. This phenomenon supports the hypothesis that substituents stabilize π–π interactions regardless of their electronic character. To further investigate the origin of substituent effects for π–π interactions, we synthesized and crystallized a series of 4‐substituted benzoyl leucine diethyl amides. Surprisingly, only two of the 4‐substituted compounds formed homochiral dimers. A comparison among the 4‐substituted compounds that crystallized as homochiral dimers and their 3‐substituted counterparts revealed that there are differences in regard to the geometry of the aromatic rings with respect to each other, which depend on the electronic nature and location of the substituent. The crystal structures of the homochiral dimers that showed evidence of direct, local interactions between the substituents on the aromatic rings also displayed nonequivalent dihedral angles in the individual monomers. The crystallographic data suggests that such “flexing” may be the result of the individual molecules orienting themselves to maximize the local dipole interactions on the respective aromatic rings. The results presented here can potentially have broad applicability towards the development of molecular recognition systems that involve aromatic interactions. 相似文献
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Heqing Tang Lihua Zhu Yutaka Harima Kazuo Yamashita Joji Ohshita Atsutaka Kunai 《Journal of Polymer Science.Polymer Physics》1999,37(15):1873-1880
UV‐visible absorption and fluorescence properties of three series of σ–π‐conjugated polymers (copolymers of alternative oligothienylene and oligosilylene units) have been studied in dioxane solution. The energies of the absorption maximum, fluorescence maximum, and the 0–0 transition are found to be linearly dependent on the reciprocal of the number of thiophene rings in the repeating unit of the polymer chain, but almost independent of the silicon atom number. The σ–π‐conjugation in the polymers results in red shift in the absorption and fluorescence maxima, higher fluorescence quantum yields, and longer fluorescence lifetimes of the polymers, with respect to their corresponding analogous α‐oligothiophenes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1873–1880, 1999 相似文献
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Electrostatic self‐assembly can be used to form supramolecular vesicles in aqueous solution. Vesicles consist of cationic G8 poly(amidoamine) dendrimers and the trivalent sulfonate dye Ar27. No classical amphiphiles are present but the interplay of electrostatics, π–π interaction and geometric factors influences the structure formation. Labeled guest molecules, both small molecules and peptides, can be included inside these vesicles and vesicles imaged by fluorescence techniques. The structure was studied by dynamic and static light scattering, small‐angle neutron scattering, confocal laser scanning microscopy, and fluorescence correlation spectroscopy. The study indicates the prospect of constructing functional nanoobjects by the self‐assembly of charged molecules in aqueous solution.
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Naofumi Naga Hitomi Nagino Midori Iwashita Tomoharu Miyanaga Hidemitsu Furukawa 《Journal of polymer science. Part A, Polymer chemistry》2015,53(11):1360-1368
Organic–inorganic hybrid gels containing Si‐vinylene units have been synthesized by a hydrosilylation reaction of tri‐ or tetra‐ethynyl aryl compounds, 1,3,5‐triethynylbenzene (TEB), 3,3′,5,5′‐tetraethynylbiphenyl (TEBP), or tetrakis(4‐ethynylphenyl)methane (TEPM), and bisdimethylsilyl compounds, 1,1,3,3‐tetramethyldisiloxane (TMDS) or 1,4‐bisdimetylsilylbenzene (BDMSB), in toluene. Network structure of the resulting gels was quantitatively characterized by a scanning microscopic light scattering. The reactions yielded the gels having homogeneous network structure of 1.5–2.9 nm mesh size under the monomer concentrations that were relatively higher than the critical gelation concentration. The gels obtained from TEB showed broad absorption in the range from 340 to 370 nm, and emission in the range from 440 to 490 nm. The TEB–BDMSB gels showed remarkable red shift of the emission in comparison with that of the corresponding reaction solutions derived from the network formed by σ–π conjugation. The TEPM–TMDS, BDMSB gels exited by 280 nm showed not only the emission peak at around 360 nm derived from TEPM, but the broad peak at around 420 nm, which should be derived from interaction between phenyl groups of TEPM in the gels. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1360–1368 相似文献
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Zun‐Ting Zhang Qian‐Guang Liu Xiao‐Bing Wang Jian‐Bin Zheng Kai‐Bai Yu 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o29-o31
The title compound, 5‐hydroxy‐4′,7‐dimethoxyisoflavone, C17H14O5, is composed of a benzopyranone moiety, a phenyl moiety and two methoxy groups. The benzopyranone ring is not coplanar with the phenyl ring, the dihedral angle between them being 56.28 (3)°. The two methoxy groups are nearly coplanar with their corresponding rings, having C—C—O—C torsion angles of 2.9 (2) and 5.9 (2)°. The molecules are linked by C—H·O hydrogen bonds into sheets containing classical centrosymmetric (8) rings. The sheets are further linked by aromatic π–π stacking interactions and C—H·O hydrogen bonds into a supramolecular structure. 相似文献
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Zachary N. Vealey Brandon Q. Mercado Patrick H. Vaccaro 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(10):730-737
Tropolone long has served as a model system for unraveling the ubiquitous phenomena of proton transfer and hydrogen bonding. This molecule, which juxtaposes ketonic, hydroxylic, and aromatic functionalities in a framework of minimal complexity, also has provided a versatile platform for investigating the synergism among competing intermolecular forces, including those generated by hydrogen bonding and aryl coupling. Small members of the troponoid family typically produce crystals that are stabilized strongly by pervasive π–π, C—H…π, or ion–π interactions. The organic salt (TrOH·iBA) formed by a facile proton‐transfer reaction between tropolone (TrOH) and isobutylamine (iBA), namely isobutylammonium 7‐oxocyclohepta‐1,3,5‐trien‐1‐olate, C4H12N+·C7H5O2−, has been investigated by X‐ray crystallography, with complementary quantum‐chemical and statistical‐database analyses serving to elucidate the nature of attendant intermolecular interactions and their synergistic effects upon lattice‐packing phenomena. The crystal structure deduced from low‐temperature diffraction measurements displays extensive hydrogen‐bonding networks, yet shows little evidence of the aryl forces (viz. π–π, C—H…π, and ion–π interactions) that typically dominate this class of compounds. Density functional calculations performed with and without the imposition of periodic boundary conditions (the latter entailing isolated subunits) documented the specificity and directionality of noncovalent interactions occurring between the proton‐donating and proton‐accepting sites of TrOH and iBA, as well as the absence of aromatic coupling mediated by the seven‐membered ring of TrOH. A statistical comparison of the structural parameters extracted for key hydrogen‐bond linkages to those reported for 44 previously known crystals that support similar binding motifs revealed TrOH·iBA to possess the shortest donor–acceptor distances of any troponoid‐based complex, combined with unambiguous signatures of enhanced proton‐delocalization processes that putatively stabilize the corresponding crystalline lattice and facilitate its surprisingly rapid formation under ambient conditions. 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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ZhongMin Geng Go Sato Kazuhiro Marumoto Masashi Kijima 《Journal of polymer science. Part A, Polymer chemistry》2016,54(21):3454-3461
Donor–π–acceptor type fluorene‐based copolymers with a sulfone unit were designed and synthesized for application in efficient pure‐blue light emitting. The electroluminescence behaviors of these copolymers were investigated by fabricating light‐emitting diodes and electrochemical cell devices. The former device little functioned but the latter worked well. The electrochemical cell devices having a configuration of ITO/PEDOT:PSS/copolymer:ionic liquid/Al exhibited purplish blue electroluminescence with an emission maximum at 434 nm (CIE coordinates (x, y) = (0.17, 0.10)) measured at 7 V. The initial positive scan of the D–π–A polysulfone based light emitting electrochemical cell with a sweep rate of 0.1 V s?1 afforded a maximum luminance of 1080 cd m?2 with a current efficiency of 1.96 cd A?1 at an operating voltage of 12.5 V. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3454–3461 相似文献