Results 281 to 290 of about 91,814 (336)

Force-field model for intramolecular radical additions

The Journal of Organic Chemistry, 1987
Ce modele permet de prevoir de facon precise la regioselectivite et la stereoselectivite des reactions de cyclisation des radicaux ...
D. C. Spellmeyer, K. N. Houk
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Enhanced Small-Molecule Assembly through Directional Intramolecular Forces

Organic Letters, 2005
[reaction: see text] Directional intramolecular interactions play a critical role in the self-assembly of donor-sigma-acceptor molecules in solution. Amide functions on the periphery of the tricyclic core stabilize a C3-symmetric monomer conformation by intramolecular hydrogen bonding and dipole-dipole interactions.
Andrew J, Lampkins, Osama, Abdul-Rahim, Hengfeng, Li, Ronald K, Castellano   +3 more
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Intramolecular forces in the water molecule in lithium sulfate monohydrate

The Journal of Chemical Physics, 1975
A study of the low−temperature infrared spectra of varyingly deuterated mulls of lithium sulfate monohydrate has afforded information on the origin of bands due to the vibrations of the water molecule in the solid. Assignments are made for the intermolecularly uncoupled modes which produce these bands in the spectrum and intramolecular coupling force ...
H. Preston Hayward, Jerome Schiffer
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The driving forces for twisted or planar intramolecular charge transfer

Physical Chemistry Chemical Physics, 2015
The driving forces for twisting or planarization of excited D–A (donor–acceptor)-type chromophore have been investigated.
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Characterization of Intermolecular and Intramolecular Interactions with the Atomic Force Microscope

2014
The atomic force microscope (AFM) is a powerful nanoscale instrument that is capable of simultaneously imaging biomolecules and measuring the forces between biomolecules attached to the probe and the surface. In this review, we provide an introduction to the experimental and theoretical considerations that are involved in studying single molecular ...
Lee, Gil U, Ivanov, Krasimir, Kilinc, Devrim, Martines, Elena, Blasiak, Agata, Li, Peng, Higgins, Michael J   +6 more
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A force field model for the transition structures of intramolecular nitrile oxide cycloadditions

Tetrahedron Letters, 1992
Abstract A force field model for nitrile oxide cycloadditions accounts for observed diastereoselectivities in inter- and intramolecular reactions controlled by steric factors.
F. BROWN, L. RAIMONDI, Y. WU, K. HOUK
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On the Effects of Intramolecular van der Waals Forces

The Journal of Chemical Physics, 1960
Evidence for the existence of strong nonbonded repulsions between atoms bonded to a given atom is cited. It is observed that bond angles in ethylene derivatives and related molecules can be correlated with a simple ``hard sphere'' model in which atomic positions are presumed to be governed by the sizes of spherical atoms packed around a given atom ...
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Calculation of intramolecular force fields from second‐derivative tensors

International Journal of Quantum Chemistry, 1996
A practical procedure (FUERZA) to obtain internal force constants from Cartesian second derivatives (Hessians) is presented and discussed. It allows a systematic analysis of pair atomic interactions in a molecular system, and it is fully invariant to the choice of internal coordinates of the molecule.
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Intramolecular Force Fields and Vibrational Amplitudes of Disulfur Monoxide Isotopes

Spectroscopy Letters, 1977
Abstract The force constants of S2O have been calculated smploying GVFF and UBFF models. The reliability of the set of force constants have been examined. The mean amplitudes of vibration have also been evaluated at three temperatures, viz., 0°K, 298·15°K and 500°K. The results have been briefly discussed.
R. K. Goel, null Rohitashava, A. N. Pandey   +2 more
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Large molecules on surfaces: deposition and intramolecular STM manipulation by directional forces

Journal of Physics: Condensed Matter, 2010
Intramolecular manipulation of single molecules on a surface with a scanning tunnelling microscope enables the controlled modification of their structure and, consequently, their physical and chemical properties. This review presents examples of intramolecular manipulation experiments with rather large molecules, driven by directional, i.e. chemical or
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