Hydrogen bonding bond lengths

Fig. 3.3 Hydrogen bonds and lengths showing the different types of hydrogen bonds, bond lengths and examples...

At room temperature hypofluorous acid HOF is a gas. Its colorless solid (mp = 156 K) melts to a pale yellow liquid. In the crystal structure, O-F = 144.2 pm, angle H-O-F =101°, and the HOF molecules are linked by O-H- O hydrogen bonds (bond length 289.5 pm and bond angle O-H- O 163°) to form a planar zigzag chain, as shown below ... 

Tjandra N and Bax A 1997 Solution NMR measurement of amide proton chemical shift anisotropy in N-15-enriched proteins. Correlation with hydrogen bond length J. Am. Chem. Soc. 119 8076-82... 

Element Electronegativity Covalent radius, pm Usual coordination number Bond with hydrogen Bond length, pm Bond energy, kj/mot ... 

One after the other, examine methanol dimer and acetic acid dimer. Do the hydrogen-bond lengths in these systems differ significantly from the optimum distance in water dimer Are the hydrogen-bond angles in these compounds significantly different from those in water dimer Rationalize your results. 

Fig. 2.6 Comparison of the calculated structures for glycine in the gas-phase and in water (COSMO solvation model). Note that the central bond angle in the zwitterionic form 1 is distorted by the hydrogen bond length of 1.96A computed for this structure in the gas phase. When solvation effects are included in the calculation using COSMO, the electrostatic interaction is reduced in magnitude due to charge screening by water, and the bond angle distortion is no longer present.

A comparison of the hydrogen bond lengths obtained from the DFT and HF methods, and from X rays experimental data [118-119] is reported in Table V. 

M. Rozenberg, A. Loewenschuss, and Y. Marcus, An empirical correlation between stretching vibration redshift and hydrogen bond length. Phys. Chem. Chem. Phys. 2, 2699 2702 (2000). 

The hydrogen bond length in Watson-Crick base pairs can be characterized using the recently developed method of measuring the cross-correlated relaxation [61] between H chemical shift anisotropy and dipole-dipole coupling of H and its hydrogen bond donor... 

N. Using the two measured cross-correlated relaxation rates, an apparent hydrogen bond length can be determined. Data for the 15N3-1H3...15N1 hydrogen bond in A-T base pairs of Antennapedia homeodomain DNA complex with a correlation time of 20 ns has been presented. 

Fig. 39. A typical molecular configuration from the Monte Carlo simulation of liquid water (from Ref. 71>). Hydrogen bond lengths and OH.. . O angles are displayed. The numbers inside the oxygen atom circles are values of the Z coordinate in A...

Keywords Covalent and ionic radii, Golden ratio, hydrogen bond length... 

L AHB. All but the first of these parameters involve the proton itself, but this is not the easiest of entities to locate. The heavier atoms A and B can be located with certainty and for this reason is the dimension commonly referred to as the hydrogen-bond length. Relationships between hydrogen-bond parameters b> a-H b AHB have been the subject of... 

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