The 19F–1H coupling constants transmitted through covalent, hydrogen bond, and van der Waals interactions

2001 ◽  
Vol 115 (12) ◽  
pp. 5498-5506 ◽  
Author(s):  
Magdalena Pecul ◽  
Joanna Sadlej ◽  
Jerzy Leszczynski
Keyword(s):  
Hydrogen Bond ◽  
Van Der Waals ◽  
Coupling Constants ◽  
Van Der Waals Interactions

Competition and cooperativity of hydrogen-bonding and tetrel-bonding interactions involving triethylene diamine (DABCO), H2O and CO2 in air

2020 ◽  
Vol 44 (6) ◽  
pp. 2328-2338 ◽  
Author(s):  
Jianming Yang ◽  
Qinwei Yu ◽  
Fang-Ling Yang ◽  
Ka Lu ◽  
Chao-Xian Yan ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Tetrel Bond

Triethylene diamine (DABCO) can interact with H2O and CO2 in air to form dimeric and trimeric complexes via hydrogen bond, tetrel bond as well as van der Waals interactions.

A Learning Method for Predicting the Binding Strength in RNA-Protein Complexes

2014 ◽  
Vol 644-650 ◽  
pp. 5291-5294
Author(s):  
Tong Wang ◽  
Jian Xin Xue ◽  
Tian Xia
Keyword(s):  
Hydrogen Bond ◽  
Protein Binding ◽  
Rna Binding ◽  
Protein Complexes ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Protein Binding Sites ◽  
Binding Strength ◽  
Rna Protein Complexes ◽  
Score Matrix

Hydrogen bond and van der Waals interactions between protein and RNA are important. We have developed a set of algorithms for predicting RNA-Protein binding strength by analyzing hydrogen bond and van der Waals interactions between protein and RNA. Firstly, we must identify the RNA-Protein binding sites. In this study, we use features including Pseudo Position-Specific Score Matrix (PsePSSM) computed by PSI-BLAST and Dipeptide Composition (DC) as feature vectors. Then, the classifier is employed to identify the residues that interact with RNA in RNA-binding protein. Then, take into account the number of amino acids hydrogen bonding and van der Waals forces to any nucleotide, the binding strength is calculated. Finally, fuzzy sets method is adopted to predict the binding strength is strong or weak. Our experiments show that the above methods are used effectively to deal with this complicated problem of predicting RNA-protein binding strength.

Proton and fluorine magnetic resonance studies of some benzoyl fluoride derivatives. Sensitivity of the fluorine shifts to intramolecular van der Waals interactions and steric effects

1977 ◽  
Vol 55 (22) ◽  
pp. 3936-3941 ◽  
Author(s):  
Ted Schaefer ◽  
Kirk Marat ◽  
Kalvin Chum ◽  
Alexander F. Janzen
Keyword(s):  
Magnetic Resonance ◽  
Van Der Waals ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Van Der Waals Interactions ◽  
Proton Proton ◽  
Out Of Plane ◽  
Spin Coupling Constants ◽  
The Individual ◽  
Spin Spin Coupling

The syntheses and the analyses of the high resolution proton and fluorine magnetic resonance spectra of the 3-fluoro-4-methyl-, 2-fluoro-5-chloro-, 2-fluoro-6-chloro-, 2,6-difluoro-, and of the pentafluorobenzoyl fluorides are reported. The spin–spin coupling constants over five bonds between the sidechain fluorine-19 and the ring protons are sensitive to intrinsic substituent perturbations. Their use in the deduction of conformational preferences is much more problematical than is the use of the corresponding proton–proton couplings in benzaldehyde derivatives. The 2-fluoro-6-chloro compound is nonplanar, as indicated by a finite magnitude of the long-range proton–fluorine coupling over six bonds. The nonplanarity is also indicated by a comparison of the through-space fluorine–fluorine coupling to those in the other compounds. The chemical shift of the sidechain fluorine moves to low field by over 35 ppm as the size of the two ortho substituents increases. The individual shifts are discussed in terms of intramolecular van der Waals interactions and of out-of-plane twisting of the COF group.

Self-Organization of 2,5-Di-n-Alkoxy-1,4-benzoquinones in the Solid State:  Molecular Recognition Involving Intermolecular Dipole−Dipole, Weak C−H···OC Hydrogen Bond and van der Waals Interactions

1996 ◽  
Vol 8 (5) ◽  
pp. 1092-1105 ◽  
Author(s):  
Erik M. D. Keegstra ◽  
Valentijn van der Mieden ◽  
Jan W. Zwikker ◽  
Leonardus W. Jenneskens ◽  
Arie Schouten ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Molecular Recognition ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Self Organization

Solvent-induced changes in 2J(H, F) for fluoroform via van der Waals interactions. Non-contact contributions to spin–spin coupling constants involving a proton?

1979 ◽  
Vol 57 (14) ◽  
pp. 1877-1880 ◽  
Author(s):  
Ted Schaefer ◽  
Harold M. Hutton ◽  
Salman R. Salman
Keyword(s):  
Van Der Waals ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Van Der Waals Interactions ◽  
Spin Orbital ◽  
Orbital Contribution ◽  
Solvent Interactions ◽  
Spin Coupling Constants ◽  
Induced Changes ◽  
Spin Spin Coupling

The spin–spin coupling between the proton and the fluorine nuclei, 2J, in fluoroform varies by 1% in a range of solvents. It is argued that 2J decreases algebraically as the van der Waals solute–solvent interactions increase in magnitude. Such a decrease is also observed for coupling constants which likely contain a substantial positive orbital contribution. If the van der Waals interactions perturb the spin–orbital term in J, then 2J in fluoroform may well contain orbital contributions, as recently calculated for 2J in methyl fluoride. In that event, the large discrepancies between observed 2J(H,F) values and those calculated by semiempirical theories of the contact term may be partially attributed to the neglect of orbital terms.

1-Benzoyl-3-[(2-benzylsulfanyl)phenyl]thiourea

2012 ◽  
Vol 68 (12) ◽  
pp. o485-o487 ◽  
Author(s):  
Tirtha Bhattacharjee ◽  
Prasanta Gogoi ◽  
Vedavati G. Puranik ◽  
Rupesh L. Gawade ◽  
Pranjit Barman
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Van Der Waals ◽  
Membered Ring ◽  
Van Der Waals Interactions ◽  
Intermolecular Hydrogen Bonds ◽  
Compound C

In the title compound, C21H18N2OS2, a strong intramolecular N—H...O hydrogen bond [N...O = 2.642 (3) Å] between the amide N atom and the benzoyl O atom forms an almost planar six-membered ring in the central part of the molecule. In the crystal, molecules are packed through weak N—H...S interactions. Intra- and intermolecular hydrogen bonds and van der Waals interactions are the stabilizing forces for the crystal structure.

A precise analysis of the 1H nuclear magnetic resonance spectrum of 2-phenyl-1,3-dithiane. Ring pucker, signs of long-range J(H,H), internal rotational barrier, and van der Waals shifts

1994 ◽  
Vol 72 (7) ◽  
pp. 1722-1727 ◽  
Author(s):  
Ted Schaefer ◽  
Jeremy P. Kunkel ◽  
Robert W. Schurko ◽  
Guy M. Bernard
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Spectrum ◽  
Resonance Spectrum ◽  
Chemical Shifts ◽  
Van Der Waals ◽  
Lone Pair ◽  
Coupling Constants ◽  
Van Der Waals Interactions ◽  
Nuclear Magnetic

The 1H nuclear magnetic resonance spectrum of 2-phenyl-1,3-dithiane, as a dilute solution in a CS2–C6D12–TMS solvent mixture at 300 K, is analyzed to yield 8 chemical shifts and 22 distinct coupling constants, nJ(H,H), n = 2–6. The coupling constant between H-2 and the para proton indicates, first, that the bisected conformer (phenyl plane perpendicular to the pseudo plane of the dithiane ring) is most stable and, second, that the apparent twofold barrier to rotation about the Csp2—Csp3 bond is 9.6 kJ/mol. The AM1, STO-3G, and STO-3G* computations confirm the twofoldedness of the barrier; the AM1 barrier is 9.4 kJ/mol. The empirical equation, [Formula: see text] reproduces the vicinal coupling constants of the CH2CH2CH2 fragments and implies puckering angles [Formula: see text] of 54°, 61°, and 64°, respectively. It is implied that 3J at [Formula: see text] is larger than at [Formula: see text] This results is discussed in terms of the latest theoretical approach to 3J in the HCCH fragment. The 4J(H,H) signs and magnitudes for the CH2CH2CH2 fragment agree reasonably well with theory. For the CH2SCH fragment, 4J(H,H) values are positive, in contrast to corresponding numbers in the propanic fragment, perhaps the first experimental values for certain rigid orientations about a heteroatom. INDO MO FPT computations on propane, dimethyl ether, and dimethyl sulfide confirm the experimental trend in 4J(H,H). 2J(H,H) and 5J(H,H) values are compared to those in related molecules. The striking differential shifts of the axial and equatorial protons are attributed to differential van der Waals interactions with the 3p lone-pair orbital on sulfur. A comparison of the ring proton chemical shifts with those in phenylcyclohexane and isopropylbenzene implies that C—S bonds are weaker net electron donors by hyperconjugation than are C—C bonds. It is also proposed that the ortho protons are deshielded by intramolecular van der Waals interactions with the 3p orbitals on the sulfur atoms.

Sign in / Sign up

Export Citation Format

Share Document