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Non‐covalent interactions play a crucial role in (supramolecular) chemistry and much of biology. Supramolecular forces can indeed determine the structure and function of a host–guest system. Many sensors, for example, rely on reversible bonding with the analyte. Natural machineries also often have a significant non‐covalent component (e.g. protein folding, recognition) and rational interference in such ‘living’ devices can have pharmacological implications. For the rational design/tweaking of supramolecular systems it is helpful to know what supramolecular synthons are available and to understand the forces that make these synthons stick to one another. In this review we focus on σ‐hole and π‐hole interactions. A σ‐ or π‐hole can be seen as positive electrostatic potential on unpopulated σ* or π(*) orbitals, which are thus capable of interacting with some electron dense region. A σ‐hole is typically located along the vector of a covalent bond such as X?H or X?Hlg (X=any atom, Hlg=halogen), which are respectively known as hydrogen and halogen bond donors. Only recently it has become clear that σ‐holes can also be found along a covalent bond with chalcogen (X?Ch), pnictogen (X?Pn) and tetrel (X?Tr) atoms. Interactions with these synthons are named chalcogen, pnigtogen and tetrel interactions. A π‐hole is typically located perpendicular to the molecular framework of diatomic π‐systems such as carbonyls, or conjugated π‐systems such as hexafluorobenzene. Anion–π and lone‐pair–π interactions are examples of named π‐hole interactions between conjugated π‐systems and anions or lone‐pair electrons respectively. While the above nomenclature indicates the distinct chemical identity of the supramolecular synthon acting as Lewis acid, it is worth stressing that the underlying physics is very similar. This implies that interactions that are now not so well‐established might turn out to be equally useful as conventional hydrogen and halogen bonds. In summary, we describe the physical nature of σ‐ and π‐hole interactions, present a selection of inquiries that utilise σ‐ and π‐holes, and give an overview of analyses of structural databases (CSD/PDB) that demonstrate how prevalent these interactions already are in solid‐state structures. 相似文献
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《Journal of computational chemistry》2018,39(2):93-104
The characteristics of the concave–convex π‐π interactions are evaluated in 32 buckybowl dimers formed by corannulene, sumanene, and two substituted sumanenes (with S and CO groups), using symmetry‐adapted perturbation theory [SAPT(DFT)] and density functional theory (DFT). According to our results, the main stabilizing contribution is dispersion, followed by electrostatics. Regarding the ability of DFT methods to reproduce the results obtained with the most expensive and rigorous methods, TPSS‐D seems to be the best option overall, although its results slightly tend to underestimate the interaction energies and to overestimate the equilibrium distances. The other two tested DFT‐D methods, B97‐D2 and B3LYP‐D, supply rather reasonable results as well. M06‐2X, although it is a good option from a geometrical point of view, leads to too weak interactions, with differences with respect to the reference values amounting to about 4 kcal/mol (25% of the total interaction energy). © 2017 Wiley Periodicals, Inc. 相似文献
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Tuning the π‐π stacking distance and J‐aggregation of DPP‐based conjugated polymer via introducing insulating polymer
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Liang Chen Haiyang Wang Jiangang Liu Rubo Xing Xinhong Yu Yanchun Han 《Journal of Polymer Science.Polymer Physics》2016,54(8):838-847
The close π–π stacking and the high J‐aggregation during the formation of fibrillar morphology in films of the poly[[2,5‐bis(2‐octyldodecyl)?2,3,5,6‐tetrahydro‐3,6‐dioxopyrrolo[3,4‐c]pyrrole‐1,4‐diyl]‐alt–[[2,2′‐(2,5‐thiophene)bis‐thieno[3,2‐b]thiophen]‐5,5′‐diyl]] (PDPPTT‐T) are demonstrated via blending with polystyrene (PS). The hydrodynamic radius (Rh) of PDPPTT‐T is decreased from 16.7 nm in the neat solution to 12.7 nm in the blend solution at the ratio of 1/20(PDPPTT‐T/PS). This phenomenon suggests that blending PS is beneficial for the disentanglement of PDPPTT‐T. The disentanglement of PDPPTT‐T facilitates the formation of fibrillar morphology. The growth of the fibrils occurs along the molecular backbones and the width of the fibrils is parallel to the π–π stacking direction. The disentanglement of PDPPTT‐T helps the molecules adjust conformation to improve J‐aggregation and decrease the π–π stacking distance. The maximum absorption is red‐shifted from 825 nm to 849 nm and the relative intensity of J‐aggregation (the 0‐0/0‐1 ratio) is increased from 1.19 to 1.60. The π–π stacking distance decreases from 3.57 to 3.52 Å. The charge‐carrier mobility will be improved in the fibrillar morphology with close π–π stacking and high J‐aggregation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 838–847 相似文献
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Joan Simó Padial Dr. René de Gelder Dr. Célia Fonseca Guerra Prof. Dr. F. Matthias Bickelhaupt Dr. Jasmin Mecinović 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(21):6268-6271
The through‐space polar–π interactions between pyridinium ion and the adjacent aromatic rings in 2,6‐diarylpyridines affect the pKa values. Hammett analysis illustrates that the basicity of pyridines correlates well with the sigma values of the substituents at the para position of the flanking aryl rings. 相似文献
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Facile Fabrication of Solid‐state Electrochemiluminescence Sensor via Non‐covalent π‐π Stacking and Covalent Bonding on Graphite Electrode
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Herein, a facile and efficient method was developed for fabrication of solid‐state electrochemiluminescence (ECL) sensor via non‐covalent π‐π stacking and covalent bonding on the graphite electrode (GE) surface. The electrode was firstly modified with 1‐aminopyrene via π‐π stacking between GE surface and the pyrene moiety. Thereafter a stable and efficient solid‐state ECL sensor was fabricated by covalent immobilization of ruthenium(II) onto the GE surface via amidation reaction between the 1‐aminopyrene and bis(2,2′‐bipyridyl)(4‐methyl‐4′‐carboxypropyl‐2,2′‐bipyridyl) ruthenium(II) bishexafluorophosphate. The sensor has been investigated using tripropylamine and tetracycline as representative analytes, and low detection limits of 0.7 nM and 3.5 nM (S/N=3) were reached, respectively. 相似文献
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Taraneh Hajiashrafi Roghayeh Zekriazadeh Keith J. Flanagan Farnoush Kia Antonio Bauz Antonio Frontera Mathias O. Senge 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(2):178-188
The supramolecular chemistry of coordination compounds has become an important research domain of modern inorganic chemistry. Herein, six isostructural group IIB coordination compounds containing a 2‐{[(2‐methoxyphenyl)imino]methyl}phenol ligand, namely dichloridobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)zinc(II), [ZnCl2(C28H26N2O4)], 1 , diiodidobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)zinc(II), [ZnI2(C28H26N2O4)], 2 , dibromidobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)cadmium(II), [CdBr2(C28H26N2O4)], 3 , diiodidobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)cadmium(II), [CdI2(C28H26N2O4)], 4 , dichloridobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)mercury(II), [HgCl2(C28H26N2O4)], 5 , and diiodidobis(2‐{(E)‐[(2‐methoxyphenyl)azaniumylidene]methyl}phenolato‐κO)mercury(II), [HgI2(C28H26N2O4)], 6 , were synthesized and characterized by X‐ray crystallography and spectroscopic techniques. All six compounds exhibit an infinite one‐dimensional ladder in the solid state governed by the formation of hydrogen‐bonding and π–π stacking interactions. The crystal structures of these compounds were studied using geometrical and Hirshfeld surface analyses. They have also been studied using M06‐2X/def2‐TZVP calculations and Bader's theory of `atoms in molecules'. The energies associated with the interactions, including the contribution of the different forces, have been evaluated. In general, the π–π stacking interactions are stronger than those reported for conventional π–π complexes, which is attributed to the influence of the metal coordination, which is stronger for Zn than either Cd or Hg. The results reported herein might be useful for understanding the solid‐state architecture of metal‐containing materials that contain MIIX2 subunits and aromatic organic ligands. 相似文献
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Sumesh Nicholas 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(3):211-215
The peptide N‐benzyloxycarbonyl‐L‐valyl‐L‐tyrosine methyl ester or NCbz‐Val‐Tyr‐OMe (where NCbz is N‐benzyloxycarbonyl and OMe indicates the methyl ester), C23H28N2O6, has an extended backbone conformation. The aromatic rings of the Tyr residue and the NCbz group are involved in various attractive intra‐ and intermolecular aromatic π–π interactions which stabilize the conformation and packing in the crystal structure, in addition to N—H...O and O—H...O hydrogen bonds. The aromatic π–π interactions include parallel‐displaced, perpendicular T‐shaped, perpendicular L‐shaped and inclined orientations. 相似文献
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Hua Cai Yan‐Ling Xiao Ying Guo Jian‐Gang Li 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(7):722-725
The complex poly[[aqua(μ2‐phthalato‐κ2O1:O2){μ3‐2‐[3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl]acetato‐κ4N2,N3:O:O′}{μ2‐2‐[3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl]acetato‐κ3N2,N3:O}dizinc(II)] dihydrate], {[Zn2(C10H8N3O2)2(C8H4O4)(H2O)]·2H2O}n, has been prepared by solvothermal reaction of 2‐[3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl]acetonitrile (PPAN) with zinc(II). Under hydrothermal conditions, PPAN is hydrolyzed to 2‐[3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl]acetate (PPAA−). The structure determination reveals that the complex is a one‐dimensional double chain containing cationic [Zn4(PPAA)4]4+ structural units, which are further extended by bridging phthalate ligands. The one‐dimensional chains are extended into a three‐dimensional supramolecular architecture via hydrogen‐bonding and π–π stacking interactions. 相似文献
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Lei Gao Yanli Zeng Xueying Zhang Lingpeng Meng 《Journal of computational chemistry》2016,37(14):1321-1327
The σ‐hole of M2H6 (M = Al, Ga, In) and π‐hole of MH3 (M = Al, Ga, In) were discovered and analyzed, the bimolecular complexes M2H6···NH3 and MH3···N2P2F4 (M = Al, Ga, In) were constructed to carry out comparative studies on the group III σ‐hole interactions and π‐hole interactions. The two types of interactions are all partial‐covalent interactions; the π‐hole interactions are stronger than σ‐hole interactions. The electrostatic energy is the largest contribution for forming the σ‐hole and π‐hole interaction, the polarization energy is also an important factor to form the M···N interaction. The electrostatic energy contributions to the interaction energy of the σ‐hole interactions are somewhat greater than those of the π‐hole interactions. However, the polarization contributions for the π‐hole interactions are somewhat greater than those for the σ‐hole interactions. © 2016 Wiley Periodicals, Inc. 相似文献
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《Angewandte Chemie (International ed. in English)》2017,56(43):13259-13263
Three compounds with phenyl and pentafluorophenyl rings bridged by (CH2)3 and (CH2)2SiMe2 units were synthesized by hydrosilylation and C−C coupling reactions. Their solid‐state structures are dominated by intermolecular π stacking interactions, primarily leading to dimeric or chain‐type aggregates. Analysis of free molecules in the gas phase by electron diffraction revealed the most abundant conformer to be significantly stabilized by intramolecular π–π interactions. For the silicon compounds, structures characterized by σ–π interactions between methyl and pentafluorophenyl groups are second lowest in energy and cannot be excluded completely by the gas electron diffraction experiments. C6H5(CH2)3C6F5, in contrast, is present as a single conformer. The gas‐phase structures served as a reference for the evaluation of a series of (dispersion‐corrected) quantum‐chemical calculations. 相似文献
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《International journal of quantum chemistry》2018,118(15)
The ability of Ex 2 Box4+ as a host, able to trap guests containing both π‐electron rich (polycyclic aromatic hydrocarbons‐PAHs) and π‐electron poor (quinoid‐ and nitro‐PAHs) moieties was investigated to shed light on the main factors that control the host–guest (HG) interaction. The nature of the HG interactions was elucidated by energy decomposition (EDA‐NOCV), noncovalent interaction (NCI), and magnetic response analyses. EDA‐NOCV reveals that dispersion contributions are the most significant to sustain the HG interaction, while electrostatic and orbital contributions are very tiny. In fact, no significant covalent character in the HG interactions was observed. The obtained results point strictly to NCIs, modulated by dispersion contributions. Regardless of whether the guests contain π‐electron‐rich or π‐electron‐poor moieties, and no significant charge‐transfer was observed. All in all, HG interactions between guests 3‐14 and host 2 are predominantly modulated by π‐π stacking. 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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Alba Montoya Braulio Insuasty Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(7):677-680
In the title compound, C26H20ClNO3, the quinoline fragment is nearly orthogonal to the adjacent aryl ring, while the rest of the molecular skeleton is close to being planar. The crystal structure contains no hydrogen bonds of any sort, but there are two π–π stacking interactions present. One, involving the quinoline ring, links molecules related by inversion, while the other, involving the two nonfused aryl rings, links molecules related by translation, so together forming a ladder‐type arrangement 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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Zhengliang Lu Yuanchao Zhao Baolian Chen Ximing Huang Chunhua Fan 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(7):718-721
The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5‐bis(2,2′‐bipyridyl‐6‐yl)‐3,4‐diazahexa‐2,4‐diene (L). The MnII centre is five‐coordinate with an approximately square‐pyramidal geometry. The L ligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one‐dimensional chain by two C—H...Cl hydrogen bonds. These chains are assembled into a two‐dimensional layer through π–π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three‐dimensional supramolecular framework is attained through π–π stacking interactions between adjacent coordinated bipyridyl groups. 相似文献
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Interactions of anions with simple aromatic compounds have received growing attention due to their relevancy in various fields. Yet, the anion–π interactions are generally very weak, for example, there is no favorable anion–π interaction for the halide anion F? on the simplest benzene surface unless the H‐atoms are substituted by the highly negatively charged F. In this article, we report a type of particularly strong anion–π interactions by investigating the adsorptions of three halide anions, that is, F?, Cl?, and Br?, on the hydrogenated‐graphene flake using the density functional theory. The anion–π interactions on the graphene flake are shown to be unexpectedly strong compared to those on simple aromatic compounds, for example, the F?‐adsorption energy is as large as 17.5 kcal/mol on a graphene flake (C84H24) and 23.5 kcal/mol in the periodic boundary condition model calculations on a graphene flake C113 (the supercell containing a F? ion and 113 carbon atoms). The unexpectedly large adsorption energies of the halide anions on the graphene flake are ascribed to the effective donor–acceptor interactions between the halide anions and the graphene flake. These findings on the presence of very strong anion–π interactions between halide ions and the graphene flake, which are disclosed for the first time, are hoped to strengthen scientific understanding of the chemical and physical characteristics of the graphene in an electrolyte solution. These favorable interactions of anions with electron‐deficient graphene flakes may be applicable to the design of a new family of neutral anion receptors and detectors. © 2012 Wiley Periodicals, Inc. 相似文献