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Hydrogen bonding shift

Presence of hydrogen bonds. Shift of IR bonds to lower wave numbers indicates the presence of hydrogen bonds. This is absorbed in alcohols, animes, carboxylic acids and amides... [Pg.240]

Spectrum 1 illustrates how the interaction with tetramethylbenzene (by hydrogen-bonding) shifts the silanol band in Beta to 3563 cm" and the bridging hydroxyls to even lower frequencies where overlapping absorption from hydrogen-bonded silanols make them difficult to detect In spectrum 1 the bands between 3100 and... [Pg.427]

IR spectroscopy has been used to study the equilibrium constant and hydrogen-bond shifts of a phenol-dibenzothiophene 7r-complex. ... [Pg.199]

The position of the NH2 vibrational modes indicates a perturbation of the NH2 group. Hydrogen bonding shifts the maxima of the stretching vibration bands to below 3370 and 3310 cm 1, respectively. [Pg.202]

Hydrogen bonding. The n hydrogen bonding shifts the absorption towards shorter wave length. Since -eleetrons on nitrogen... [Pg.220]

Ditchfield, R. and McKinney, R. E., Molecular orbital studies of the NMR hydrogen bond shift, Chem. Phys. 13, 187-194 (1976). [Pg.46]

NMR chemical shift. The hydrogen bond shift of 8-14 ppm is considerably smaller than noted for hydrogen bond induced chemical shift for carbonyl group 1 0 NMR chemical shifts(vide supra). [Pg.588]

FIGURE 15. Solvatochromic hydrogen-bond shifts for 4-nitrophenol (longest wavelength ii n transition) in HBA solvents plotted against the enthalpy of hydrogen-bond formation of 4-fluorophenol in pure HBA solvents ... [Pg.592]

Fig. 11 Jl. Schematic representation of a synthetic triple-strand hydrogen-bonded structure designed to undergo hydrogen-bond shifts upon metal binding... Fig. 11 Jl. Schematic representation of a synthetic triple-strand hydrogen-bonded structure designed to undergo hydrogen-bond shifts upon metal binding...
Other correlations of NMR hydrogen-bonding shifts have been noted, e.g. with pK of proton donor, with for OD stretchings and for C=C stretching (of propargyl bromide),and with AG of... [Pg.511]

The IR spectroscopy, among others, is the most useful. The frequency shift of the X—H stretching band on complex formation (Av) is known as the hydrogen-bond shift. The lower-frequency shift Av of ordinary hydrogen bonds varies from ca. 100-500 cm. but the shifts are... [Pg.1577]

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See also in sourсe #XX -- [ Pg.117 ]



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Hydrogen shift

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