CH/? hydrogen bonds in crystals

Nishio, Motohiro

doi:10.1039/b313104a

Cited by 1,389 publications

(825 citation statements)

References 446 publications

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“…Et 2 O, similar close contacts are observed between molecules of 2, but this time involving the methyl group of one tolyl substituent (C7...H212 ii = 2.85 Å, C7...C21 ii = 3.764(3) Å, symmetry code ii = -1 + x, y, z). Packing motifs based on C-H....C alkyne contacts are well established in the solid state structures of alkynes with aromatic substituents, [44][45][46][47][48][49] and C-H....C alkyne interactions are ubiquitous among compounds containing R 3 PAuC≡C units (CSD v 5.3 with May 2009 updates, Conquest v. 1.11), [17] involving both aromatic and aliphatic C-H units. There are no significant intermolecular Au...Au contacts in either 1 or 2, the closest separations being Au2...Au2 i = 4.763(1) Å in 1 (symmetry code i = 2 -x, -y, -z), and Au1...Au1 iii = 5.303(1) Å in 2 (symmetry code iii = 1 -x, 1 -y, -z).…”

Section: Synthesis and Solution Characterizationmentioning

confidence: 99%

Structural and Photophysical Properties of (Phosphane)gold(I)‐Decorated 4,4′‐Diethynyl‐2,2′‐bipyridine Ligands

et al. 2009

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Treatment of 4,4′‐diethynyl‐2,2′‐bipyridine with R3PAuCl (R = Ph, 4‐Tol, Et, iPr) leads to the formation of a family of (phosphane)gold(I)‐decorated 4,4′‐diethynyl‐2,2′‐bipyridine ligands. The solid‐state structures of the compounds are significantly affected by the change from aryl‐ to alkyl‐substituted phosphanes, whereas the progression from ethyl to isopropyl substituents leads to a subtle change in the packing that results in the propagation of two different polymeric chain motifs, both supported by close Au···Au contacts [3.1239(1) Å for R = Et, and 3.395(1) Å for R = iPr]. In CH2Cl2 solution, each of the compounds 1–4 is a dual emitter at room temperature. When the excitation wavelength is approximately 238 nm, the emission spectra of 1 and 2 exhibit new bands at 288 and 570 nm at the expense of the original emissions. The photodegradation is not inconsistent with the formation of gold nanoclusters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Synthesis and Solution Characterizationmentioning

confidence: 99%

Structural and Photophysical Properties of (Phosphane)gold(I)‐Decorated 4,4′‐Diethynyl‐2,2′‐bipyridine Ligands

et al. 2009

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“…Although weak interactions have been detected in synthetic molecules, it is difficult to quantify them experimentally because of very weak nature vis-à-vis conventional hydrogen bonds. Recently, some weak noncovalent interactions like C-H/p, [11][12][13] C-H/F-C, 14 C-H/O, 15,16 N/O¼ ¼C, 17 X/X (Cl, Br, S, Se), [18][19][20] C-H/ N, 21 X-H/p, [22][23][24] and Se/F 25 have been explored for stabilizing specific conformations of man-made small molecules and molecular assemblies.…”

Section: Michiya Fujiki 4638mentioning

confidence: 99%

Nonclassical forces: Seemingly insignificant but a powerful tool to control macromolecular structures

Fujiki

Saxena

2008

J. Polym. Sci. A Polym. Chem.

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Strong chemical forces such as covalent and ionic bonds are responsible for building discrete molecules, nature dwells on noncovalent forces weaker by three orders in magnitude, like the hydrophobic effect, hydrogen bonding, and van der Waals forces. Despite being weak, they possess the potential to drive spontaneous folding or unfolding of proteins and nucleic acids and the recognition between complimentary molecular surfaces. The power of these forces lies in the cooperativity with which they act, thereby generating a cumulative effect of many bonding interactions occurring together. Many ongoing research aims to translate the potential of these forces to the synthetic world to create desired structures with specific chemical functions. Achieving this offers unlimited opportunities for designing and synthesizing the most complex structures with specific applications. This highlight aims to reflect the critical role these noncovalent forces play in controlling macromolecular structures, which hold immense untapped potential for applications defying conventions, and briefly touches on the concept of homochirality in nature based on chiral and weak noncovalent interactions in synthetic nonpolar Si‐catenated polymers. It sheds some light on the discovery and characterization of Si/F‐C interactions in fluoroalkylated polysilanes in chemosensing of fluoride ions and nitroaromatics with a great sensitivity and selectivity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4637–4650, 2008

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“…The measured π-π distances of 3.704 and 3.253 Å respectively suggests π-π stacking and C-H-π interaction. [20,21] The distances of 2.614 and 2.734 Å respectively indicate a good hydrogen bonding of phenyl hydrogen with carbonyl oxygen and nitrogen atoms in compound 1.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Crystal Structure and in vitro DNA Binding Studies of Combretastatin A-4 Analogue

Rizvi¹,

Dangat²,

Yaseen³

et al. 2015

Croat. Chem. Acta

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Synthesis of a novel Combretastatin A-4 analogue using Schiff's reaction of benzil and 4-aminoantipyrine has been achieved under solvent free conditions. The structure of compound was examined spectroscopically and confirmed from single crystal diffraction studies. The synthesized Combretastatin A-4 analogue was investigated for its DNA binding ability as the plausible mechanism for its antitumor activity. The binding propensity of the synthesized compound with calf-thymus (CT) DNA was monitored with absorption and emission spectrophotometric titrations. The calculations predict a binding constant of 7.24 × 10 4 for the complex of the synthesized compound with CT DNA which is comparable in magnitude to that of DNA binding of bactericidal drug enoxacin and typical intercalation indicator ethidium bromide (EB). Competitive binding studies of the synthesized compound with EB using fluorescence titration reveal that it displaces the DNA-bound EB and binds in intercalative mode which was further supported by circular dichroism (CD) spectroscopy. The probable site and binding energy of the compound with DNA was further theoretically investigated by molecular docking studies. The significant DNA binding ability of the synthesized Combretastatin A4 analogue as revealed from this study could be related to the anticancer activity of the Combretastatin A4.

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CH/? hydrogen bonds in crystals

Cited by 1,389 publications

References 446 publications

Structural and Photophysical Properties of (Phosphane)gold(I)‐Decorated 4,4′‐Diethynyl‐2,2′‐bipyridine Ligands

Structural and Photophysical Properties of (Phosphane)gold(I)‐Decorated 4,4′‐Diethynyl‐2,2′‐bipyridine Ligands

Nonclassical forces: Seemingly insignificant but a powerful tool to control macromolecular structures

Synthesis, Crystal Structure and in vitro DNA Binding Studies of Combretastatin A-4 Analogue

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