Infra-red spectra and solvent effects. Part 1.—X—H stretching frequencies

Abstract

It is shown that the frequency shifts of the NH stretching mode of pyrrole in a variety of different solvents can be plotted directly against the corresponding shifts of many X-H stretching vibrations in the same solvents. The significance of the results obtained is discussed in relation to complex formation and hydrogen bonding.

Vibrational Spectroscopy of Zeolites

“…We will demonstrate now that this observation can be substantiated from a large amount of experimental observations obtained with different bases and different zeolites, so proving its general validity. We anticipate that this general correlation, which is an extension to heterogeneous systems of the well known Bellamy-Hallam-Williams (BHW) relationship extensively documented for the homogeneous phase, 43,44 will form the basis of the spectroscopic method for the acid strength evaluation of the Brønsted groups of zeolitic systems.…”

“…30 The gradual shift to lower frequency of the For every adsorbate with PA in the range from 118 to 196 kcal mol 1 we can determine the shift N n Br of the Brønsted sites and of the silanols. We may then plot them as a graph (Figure 15) in order to verify if the BHW relation, whose validity has been well established in solution, 43,44 is also holding for the hydrogen-bonding interactions occurring in the zeolite channels.…”

Nature and Estimation of Functional Groups on Solid Surfaces

“…In solution, the wavenumber shifts of two H-bond donors can be correlated by plotting the relative wavenumber shift L\V/vo of one donor with respect to that for another [177]. Such graphs give linear relationships and chemically very different H-bond acceptors fit the same straight line provided the proton bearing atoms of the donors are identical [178].…”

Secondary Kinetic Isotope Effects in Bimolecular Nucleophilic Substitutions. V. The Role of the Solvent in the Reaction Between Methyl Iodide and Pyridine

“…However, there is some indication of a parallel between the rate ratios and specific solventsolute interactions. One measure of specific solvent-solute interactions has been advanced by Bellamy et al (21) who measured the frequency shift for the stretching frequency of X-H dipoles between the vapor and dissolved species for a large number of solvents. Using the N-H bond of pyrrole as the X-H dipole the relative frequency shift 103Av/v, where Av is the X-H stretching frequency in the vapor minus that in the solvent, has a value of 20.4 for benzene, 22.9 for nitrobenzene, and 35 to 47 for ketones (39.6 for acetone).…”