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Crystallization of the title compound, C8H8N4O2, results in the formation of one- dimensional chains of imidazole ( im) molecules linked together by strong hydrogen bonds. The O center dot center dot center dot N( im) separation a...
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Crystallization of the title compound, C8H8N4O2, results in the formation of one- dimensional chains of imidazole ( im) molecules linked together by strong hydrogen bonds. The O center dot center dot center dot N( im) separation and O - H( center dot center dot center dot N) distance are 2.6906 ( 17) and 1.74 ( 2) angstrom, respectively, and the O - H center dot center dot center dot N angle is 173 ( 2)degrees. The one- dimensional chains are weakly pi stacked along the b axis, with centroid- to- centroid separations of 3.678 ( 2) angstrom between five- and six- membered rings and 3.963 ( 2) angstrom between six- membered rings. Each molecule is arranged around an inversion center.
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The title organometallic compound, fac-tricarbonyl-2kappa(3) C-(4,4'-dimethyl-2,2'-bipyridine)-2kappa(2) N,N'-triphenyl-1kappa(3) C-1-tin(II)-rhenium(I)(Sn-Re), [ReSn(C6H5)(3)(C12H12N2)(CO)(3)], contains three unique pi-pi stackin...
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The title organometallic compound, fac-tricarbonyl-2kappa(3) C-(4,4'-dimethyl-2,2'-bipyridine)-2kappa(2) N,N'-triphenyl-1kappa(3) C-1-tin(II)-rhenium(I)(Sn-Re), [ReSn(C6H5)(3)(C12H12N2)(CO)(3)], contains three unique pi-pi stacking interactions. The result is an infinite chain of uninterrupted alternating intra- and intermolecular offset pi-pi stacking interactions throughout the crystal lattice. This extended pi-pi stacking arrangement, and an additional isolated intramolecular pi-pi interaction between the remaining 4,4'-dimethyl- 2,2'-bipyridine ring and a second phenyl group, impose geometric constraints on the Re and Sn atoms, yielding distorted octahedral and tetrahedral coordinations, respectively, for the metal centers.
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We report herein the synthesis and properties of it-stacked dimeric and polymeric compounds that consisted of hexabenzocoronene (HBC) and xanthene as the stacked pi-electron system and the scaffold, respectively; the compounds wer...
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We report herein the synthesis and properties of it-stacked dimeric and polymeric compounds that consisted of hexabenzocoronene (HBC) and xanthene as the stacked pi-electron system and the scaffold, respectively; the compounds were obtained by Sonogashira-Hagihara coupling. The obtained polymer was separated into three fractions, and the through-space conjugation effect was estimated. HBC units were layered in proximity (approximately 3.4 angstrom), leading to pi-pi stacking in the ground and excited states. (C) 2015 Elsevier Ltd. All rights reserved.
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In the crystal structure of 1,1'-(1,3-propanediyl)bis(5-methyl-6-methylthio-4, 5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one), C17H20N8O2S2, the pairs of pyrazolo[3,4-d]pyrimidine rings of the molecules stack, due to intramolecular ...
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In the crystal structure of 1,1'-(1,3-propanediyl)bis(5-methyl-6-methylthio-4, 5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one), C17H20N8O2S2, the pairs of pyrazolo[3,4-d]pyrimidine rings of the molecules stack, due to intramolecular pi-pi interactions, between the heterocyclic rings. [References: 22]
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Acenes represent interesting platforms on which to add [60]fullerenes via Diels-Alder cycloaddition reactions.For unsubsti-tuted acenes,the most reactive positions are the center-most rings.Large acenes can accommodate more than o...
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Acenes represent interesting platforms on which to add [60]fullerenes via Diels-Alder cycloaddition reactions.For unsubsti-tuted acenes,the most reactive positions are the center-most rings.Large acenes can accommodate more than one [60]fullerene cycloaddition and these reactions become facile once suitable directing substituents (e.g.phenyl groups) are added to the acene.In these cases,[60]fullerenes add in a syn-diastereoselective fashion due to favorable pi-pi stacking interactions between adjacent [60] fullerene moieties.The pi-pi stacking interactions provide further stabilization to these adducts.Several cis-bis[60]fullerene-acene adducts have been prepared in modest to excellent yield and one cis,cis-tris[60]fullerene-heptacene adduct has also been prepared.
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2,7-Substituted 9,10-bis (phenylethynyl)anthracenes with bulky phenol residues were synthesized and investigated for their antiparallel molecular arrangement. UV-vis absorption and photoluminescence properties and molecular mechan...
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2,7-Substituted 9,10-bis (phenylethynyl)anthracenes with bulky phenol residues were synthesized and investigated for their antiparallel molecular arrangement. UV-vis absorption and photoluminescence properties and molecular mechanics calculation indicate that they formed an antiparallel pi-pi stacked dimer, which was strongly associated by hydrogen bonding and pi-pi interaction. This strongly associated dimer structure was supported by AFM images of specimens prepared on mica by spin casting dilute chloroform/hexane (2/8 v/v) solution. However, the absence of intradimer hydrogen bonding resulted in the offset stacking, which was confirmed from the single crystal X-ray analysis.
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Various interesting supramolecular systems which self-assemble by noncovalent interactions have been developed rapidly.Cram et al.reported velcrand which dimerize to velcraplex by solvophobic n-n stacking interactions.Based on thi...
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Various interesting supramolecular systems which self-assemble by noncovalent interactions have been developed rapidly.Cram et al.reported velcrand which dimerize to velcraplex by solvophobic n-n stacking interactions.Based on this concept bisvelcrand composed of two velcrand units bridged in back-to-back fashion by covalent bond was reported to self-assemble oligovelcraplex only by solvophobic pi-pi stacking interactions.
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Reactions of a freshly prepared Zn(OH)(2-2x)(CO3)(x)(.)yH(2)O precipitate, phenanthroline with azelaic and sebacic acid in CH3OH/H2O afforded [Zn(phen)(C9H15O4)(2)] (1) and [Zn-2(phen)(2)(H2O)(2)(C10H16O4)(2)](.)3H(2)O (2), respec...
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Reactions of a freshly prepared Zn(OH)(2-2x)(CO3)(x)(.)yH(2)O precipitate, phenanthroline with azelaic and sebacic acid in CH3OH/H2O afforded [Zn(phen)(C9H15O4)(2)] (1) and [Zn-2(phen)(2)(H2O)(2)(C10H16O4)(2)](.)3H(2)O (2), respectively. They were structurally characterized by X-ray diffraction methods. Compound 1 consists of complex molecules [Zn(phen)(C9H15O4)(2)] in which the Zn atoms are tetrahedrally coordinated by two N atoms of one phen ligand and two O atoms of different monodentate hydrogen azelaato groups. Intermolecular C(alkyl)-H(...)pi interactions and the intermolecular C(aryl)-(HO)-O-... and O-(HO)-O-... hydrogen bonds are responsible for the supramolecular assembly of the [Zn(phen)(C9H15O4)(2)] Complexes. Compound 2 is built up from crystal H2O molecules and the centrosymmetric binuclear [Zn-2(phen)(2)(H2O)2(C10H16O4)(2)] complex, in which two [Zn(phen)(H2O)](2+) moieties are bridged by two sebacato ligands. Through the intermolecular C(alkyl)-(HO)-O-... hydrogen bonds and pi-pi stacking interactions, the binuclear complex molecules are assembled into layers, between which the lattice H2O molecules are sandwiched. Crystal data: (1) C2/c (no. 15), a 13.887(2), b = 9.790(2), c = 22.887(3) Angstrom, beta = 107.05(1)degrees, U = 2974.8(8) Angstrom(3), Z = 4; (2) P (1) over bar (no. 2), a = 8.414(1), b = 10.679(1), c = 14.076(2) Angstrom, alpha = 106.52(1)degrees, beta = 91.56(1)degrees, gamma = 99.09(1)degrees, U = 1193.9(2) Angstrom(3), Z = 1. [References: 14]
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The crystal structures of six complexes containing phenazine and a dicarboxylic acid are discussed. In each structure extended tapes are formed. The packing of these tapes is discussed with respect to the influence of the aromatic rings.
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The halogen bonding and pi-pi stacking interactions between pyrazine (C4H4N2) and fluoro substituted iodobenzene C6H5-nFnI (n = 0, 1, 2, 3, 4, and 5) have been discussed at the M062x-D3/aug-cc-pVTZ level. The calculated interactio...
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The halogen bonding and pi-pi stacking interactions between pyrazine (C4H4N2) and fluoro substituted iodobenzene C6H5-nFnI (n = 0, 1, 2, 3, 4, and 5) have been discussed at the M062x-D3/aug-cc-pVTZ level. The calculated interaction energy shows that the halogen bonding interactions are weaker than the corresponding pi-pi stacking interactions in C6H5-nFnI (n = 0, 1, and 2)-C4H4N2 complexes, while the halogen bonding interactions are stronger than the corresponding pi-pi stacking interactions in C6H5-nFnI (n = 3, 4, and 5)-C4H4N2 complexes. According to SAPT analysis, it is reveals that the electrostatic energy are the primary source of the attraction for the halogen bonding interactions while the pi-pi stacking interactions are dominantly dispersion energy. When the halogen bond and pi-pi stacking interaction coexist, we find out that the formation of pi-pi stacking will lead to stronger halogen bond interaction and the converse is also true.
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