Weak hydrogen bonding. Part 2. The hydrogen bonding nature of short C–H ⋯π contacts: crystallographic, spectroscopic and quantum mechanical studies of some terminal alkynes

Steiner, Thomas; Starikov, E. B.; Amado, Ana M.; Teixeira‐Dias, J. J. C.

doi:10.1039/p29950001321

Cited by 158 publications

(102 citation statements)

References 58 publications

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“…The latter can accept hydrogen bonds directed at the C=C bond, so that arrays of the type X-H···C=C-H···Y can be formed. Within such chains, cooperativity enhancement has been theoretically calculated for the system C=C-H···C=C-H···C=C [16], and was experimentally observed (by infrared spectroscopy) for O-H-··C=C-H···O-H chains in the crystalline sex steroid mestranol [17].…”

Section: Cooperativitymentioning

confidence: 97%

Weak Hydrogen Bonds

Steiner

1999

Implications of Molecular and Materials Structure for New Technologies

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Section: Cooperativitymentioning

confidence: 97%

Weak Hydrogen Bonds

Steiner

1999

Implications of Molecular and Materials Structure for New Technologies

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“…The C3C4 (1.424(3) Å) and C4C5 (1.450(3) Å) bond lengths are longer than other CC bond lengths in the same benzene ring. Classical NH···O hydrogen bonding according to [3] …”

Section: Discussionmentioning

confidence: 99%

Refinement of the crystal structure of propionaldehyde 2,4-dinitrophenylhydrazone, C9H10N4O4

Yang¹

2007

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of material 2,4-dinitrophenylhydrazine (1 mmol, 0.198 g) was dissolved in anhydrous ethanol (10 ml), H 2 SO 4 (98 %, 0.5 ml) was added to this, the mixture was stirred for several minutes at 351 K, propionaldehyde (1 mmol, 0.058 g) in ethanol (5 ml) was added dropwise and the mixture was stirred at refluxing temperature for 5 h. The product was separated and recrystallized in dichloromethane, red single crystals were obtained after 3 d. Discussion2,4-Dinitrophenylhydrazine is a reagent which is widely used for the condensation with aldehydes and ketones. Several phenylhydrazone derivatives have been shown to be potentially DNAdamaging and are mutagenic agents [1]. As part of our interest in the study of the coordination chemistry of Schiff base, we have synthesized the title compound and report its refined crystal structure. Due to the modern technique, more accurate data of the title compound firstly published in [2] are presented. In the title crystal structure, the molecule has a dihedral angle of 16.8 (2)

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“…Previously, only presumptions about the geometry of the motions of the donor and acceptor of the aromatic H bond had been reported. Calculations and structural studies 3,[23][24][25][26][27] have indicated that the directionality of the aromatic H bond is extremely flexible. Our study provides now more precise information, showing that the donor rotates in a specific way, and the acceptor undergoes strongly damped librational mo- tion with a partially diffusive character.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

The dynamical properties of the aromatic hydrogen bond in NH4(C6H5)4B from quasielastic neutron scattering

Jalarvo¹,

Desmedt

Lechner³

et al. 2006

The Journal of Chemical Physics

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NH 4 ͑C 6 H 5 ͒ 4 B represents a prototypical system for understanding aromatic H bonds. In NH 4 ͑C 6 H 5 ͒ 4 B an ammonium cation is trapped in an aromatic cage of four phenyl rings and each phenyl ring serves as a hydrogen bond acceptor for the ammonium ion as donor. Here the dynamical properties of the aromatic hydrogen bond in NH 4 ͑C 6 H 5 ͒ 4 B were studied by quasielastic incoherent neutron scattering in a broad temperature range ͑20ഛ T ഛ 350 K͒. We show that in the temperature range from 67 to 350 K the ammonium ions perform rotational jumps around C 3 axes. The correlation time for this motion is the lifetime of the "transient" H bonds. It varies from 1.5 ps at T = 350 K to 150 ps at T = 67 K. The activation energy was found to be 3.14 kJ/ mol, which means only 1.05 kJ/ mol per single H bond for reorientations around the C 3 symmetry axis of the ammonium group. This result shows that the ammonium ions have to overcome an exceptionally low barrier to rotate and thereby break their H bonds. In addition, at temperatures above 200 K local diffusive reorientational motions of the phenyl rings, probably caused by interaction with ammonium-group reorientations, were found within the experimental observation time window. At room temperature a reorientation angle of 8.4°± 2°and a correlation time of 22± 8 ps were determined for the latter. The aromatic H bonds are extremely short lived due to the low potential barriers allowing for molecular motions with a reorientational character of the donors. The alternating rupture and formation of H bonds causes very strong damping of the librational motion of the acceptors, making the transient H bond appear rather flexible.

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Weak hydrogen bonding. Part 2. The hydrogen bonding nature of short C–H ⋯π contacts: crystallographic, spectroscopic and quantum mechanical studies of some terminal alkynes

Cited by 158 publications

References 58 publications

Weak Hydrogen Bonds

Weak Hydrogen Bonds

Refinement of the crystal structure of propionaldehyde 2,4-dinitrophenylhydrazone, C9H10N4O4

The dynamical properties of the aromatic hydrogen bond in NH4(C6H5)4B from quasielastic neutron scattering

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