S-OH stretch

Four IR absorption bands have been identified in the spectrum of the hydroxysulfonyl radical (HOSO 2) which has been obtained by the reaction of hydroxyl radicals with sulfur dioxide in argon matrix at 11 K16. The observed bands at 3539.9 and 759.5 cm 1 have been assigned to O—H and S—OH stretching modes while the bands at 1309.2 and 1097.3 cm-1 have been assigned to the asymmetric and symmetric stretching modes of the double bonded S02 moiety. These data are consistent with the theoretical prediction on the geometry of the hydroxysulfonyl radical12. 

Adsorbed HSO ions should present the S-OH stretching vibration just above 900 cm . This band, which is surface-allowed for bisulfate adsorbed either through... 

Figure Bl.5.15 SFG spectrum for the water/air interface at 40 °C using the ssp polarization combination (s-, s- and p-polarized sum-frequency signal, visible input and infrared input beams, respectively). The peaks correspond to OH stretching modes. (After [ ].)...

The infrared spectra of alcohols change markedly with increasing concentration. For example, at very low concentration, the infrared spectrum of te/t-butyl alcohol in carbon tetrachloride contains a single sharp band at approximately 3600 cm corresponding to the OH stretching motion. As the alcohol s concentration increases (by adding more alcohol to the sample), a second broad OH stretch band grows in at approximately 3400 cm and eventually replaces the other band. 

The evidence presented for the formation of hydrogen bonds with sulphoxides and sulphones was first reported by Barnard. Fabian and Koch, who measured the characteristic infra-red stretching frequency shifts of the S—O bond in the presence of MeOH in Simultaneously the OH stretching band of MeOH at... 

Look at Fig. 118. Here s a fine example of a pair of alcohols if ever there was one. See the peak (some might call it trough) at about 3400 cm 1(2.9 fan) That s due to the OH group, specifically the stretch in the O—H bond, the OH stretch. 

D. Rueda, O. V. Boyarkin, T. R. Rizzo, I. Mukhopadhyay, and D. S. Perry, Torsion rotation analysis of OH stretch overtone torsion combination bands in methanol. J. Chem. Phys. 116,... 

M. Paolantoni, P. Sassi, A. Morresi, and R. S. Cataliotti, Raman noncoincidence effect on OH stretching profiles in liquid alcohols. J. Raman Spectr. 37, 528 537 (2006). 

It will not have escaped the reader s notice that Walrafen s analysis 39> of the OH stretching region of the vibrational spectrum of the liquid also uses a... 

A homoleptic bulky a,y-diketonate yttrium complex (fod = 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionate) was immobihzed on MCM-41.280 ( s = 1140m g, Vp = 0.93 cm g, dp = 2.7 nm) and a monopodaUy anchored surface species 6 has been proposed (Scheme 12.5). As suggested by FTIR (strong band for the Si-OH stretch vibration) as well as metal and carbon analysis (circa 3.4 wt% Y, fod/Y circa 2) only around half of the silanol population has been consumed [110]. 

Figure 1. VCD in the OH-stretching region of (—)-(2S,3S)-dimethyl tartrate, 0.01 M in CCl, at three temperatures. Sample path length 0.48 cm, time constant 10 s, resolution 16 cm. (Reproduced with permission from ref. 51. Copyright 1980 American Chemical Society.)...

The complexity of the physical properties of liquid water is largely determined by the presence of a three-dimensional hydrogen bond (HB) network [1]. The HB s undergo continuous transformations that occur on ultrafast timescales. The molecular vibrations are especially sensitive to the presence of the HB network. For example, the spectrum of the OH-stretch vibrational mode is substantially broadened and shifted towards lower frequencies if the OH-group is involved in the HB. Therefore, the microscopic structure and the dynamics of water are expected to manifest themselves in the IR vibrational spectrum, and, therefore, can be studied by methods of ultrafast infrared spectroscopy. It has been shown in a number of ultrafast spectroscopic experiments and computer simulations that dephasing dynamics of the OH-stretch vibrations of water molecules in the liquid phase occurs on sub-picosecond timescales [2-14],... 

Ultrafast proton transfer. The diffusion-controlled limit for second-order rate constants (Section A3) is 1010 M 1 s 1. In 1956, Eigen, who had developed new methods for studying very fast reactions, discovered that protons and hydroxide ions react much more rapidly when present in a lattice of ice than when in solution.138 He observed second-order rate constants of 1013 to 1014 M 1 s These represent rates almost as great as those of molecular vibration. For example, the frequency of vibration of the OH bond in water is about 1014 s . The latter can be deduced directly from the frequency of infrared light absorbed in exciting this vibration Frequency v equals wave number (3710 cm-1 for -OH stretching) times c, the velocity of light (3 x 1010 cm s ). 

These conclusions were ratified in a second paper134 which includes also 2,4-dithiouracil. The appearance of the N1H and/or N3H stretches and the absence of the SH and OH stretches in the spectrum of 2- and 4-thiouracil confirmed that these molecules exist only in the oxo-thione form. Similar findings for 2,4-dithiouracil showed that this molecule exists only as a dithione tautomeric form in an inert matrix. The spectra of S-methylated thiouracils are substantially different they present an absorption in the typical NH stretching range and another one near 3570 cm-1, which is the region characteristic for the OH stretching modes. 

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