Absorption spectra sulfoxide

Kemp and coworkers employed the pulse radiolysis technique to study the radiolysis of liquid dimethyl sulfoxide (DMSO) with several amines as solutes [triphenylamine, and N, A, A, N -tetramethyl-p-phenylenediamine (TMPD)]. The radiolysis led to the formation of transient, intense absorptions closely resembling those of the corresponding amine radical cations. Pulse radiolysis studies determine only the product Ge, where G is the radiolytic yield and e is the molar absorption. Michaelis and coworkers measured e for TMPD as 1.19 X 10 m s and from this a G value of 1.7 is obtained for TMPD in DMSO. The insensitivity of the yield to the addition of electron scavenger (N2O) and excited triplet state scavenger (naphthalene) proved that this absorption spectrum belonged to the cation. 

Solvated electrons are known to be formed in amines, amides, dimethyl sulfoxide, and many other liquids that will not be discussed here. Note that, except for the yield and time scale of observation, the production of es itself is not related to polarity. Thus, the es absorption spectrum has indeed been observed in nonpolar liquids both at low temperatures and room temperature (Taub and... 

The fluorescence of TPHA 3 is not a mirror image of its absorption spectrum and the emission intensity is sensitive to concentrations greater than 10 M. The excitation profile of 3 also varies with concentration, believed to be due to aggregation of TPHA in solution and only emulates the ultraviolet-visible (UV-Vis) spectrum at concentrations less than 10 M. The Aem decreased from 633 nm in toluene to 619 nm in dimethyl sulfoxide (DMSO), and this is thought to be indicative of a polar ground state and nonpolar excited state <1998JA2989>. 

A close packing of the guest molecules was also reflected in the red shift in the absorption spectrum of the TPP-C intercalates. Although the absorption spectrum of TPP-C peaks at 414 nm in water and at 420 nm in dimethyl sulfoxide (DMSO), it shifts to 439 nm upon intercalation into the galleries of LDH (Fig. 52) [101b],... 

There has been no report on the spectrum of methionine sulfone, which is found in hydrolyzates of performate-oxidized proteins. It will probably be not very different from cysteic acid at wavelengths > 2000 A, since simple sulfones are generally transparent to 1800 A (Koch, 1950). Methionine sulfoxide is a stable amino acid found in human urine, in a variety of plant tissues, and as an intermediate in the oxidation of methionine to the sulfone. Its absorption spectrum has not been recorded. The sulfoxide chromophore is usually a broad band, located around 2100 A and of about the same intensity as alkyl sulfides (Koch, 1950). An interesting... 

N-oxidations, sulfoxidations, dealkylations, deaminations, dehalogenations, and others (Wislocki et al. 1980). These isozymes are responsible for the oxidation of different substrates or for different types of oxidation of the same substrate. Carbon monoxide binds with the reduced form of the cytochrome, forming a complex with an absorption spectrum peak at 450 nm. This is the origin of the name of the enzyme. As a result of the complex, inhibition of the oxidation process occurs. 

Figure 5. Absorption spectrum of pentaammine (S)-2-chloropropionato cobalt-(III) tetraphenylborate in ("lower set) water (as ClOf salt), hexamethylphosphor-triamide (hmpa), dimethyl sulfoxide, N-metkylformamide (nmf), N,N-dimethyl-formamide (dmf) ("upper set) acetonitrile, methanol, ethanol, acetone, pyridine (py) and tetrahydrofuran (thf). The reference contained tetraphenylborate (as Na salt) at the same concentration as the solution of the complex.

The absorption spectrum of the sulfoxide chromophore conjugated to aromatic nuclei has also been examined [6,7,9,15-17]. There are generally three bands for simple aryl alkyl sulfoxides between 200 and 300 ran. The middle band is most associated with the sulfoxide function because of the solvent effect, which parallels that of dialkyl sulfoxides. In some solvents, the central band, which is stronger than the benzene-like low energy absorption, overwhelms and hides the low energy band [10,17]. Figure 2 illustrates that an insulating CH2 decouples the benzene and SO chromophores save for the intensity of the sulfoxide absorption, dibenzyl sulfoxide appears as approximately the sum of bibenzyl and DMSO. 

The role of IR spectroscopy in the early penicillin structure studies has been described (B-49MI51103) and the results of more recent work have been summarized (B-72MI51101). The most noteworthy aspect of a penicillin IR spectrum is the stretching frequency of the /3-lactam carbonyl, which comes at approximately 1780 cm" This is in contrast to a linear tertiary amide which absorbs at approximately 1650 cm and a /3-lactam which is not fused to another ring (e.g. benzyldethiopenicillin), which absorbs at approximately 1740 cm (the exact absorption frequency will, of course, depend upon the specific compound and technique of spectrum determination). The /3-lactam carbonyl absorptions of penicillin sulfoxides and sulfones occur at approximately 1805 and 1810 cm respectively. The high absorption frequency of the penicillin /3-lactam carbonyl is interpreted in terms of the increased double bond character of that bond as a consequence of decreased amide resonance, as discussed in the X-ray crystallographic section. Other aspects of the penicillin IR spectrum, e.g. the side chain amide absorptions at approximately 1680 and 1510 cm and the carboxylate absorption at approximately 1610 cm are as expected. 

Anhydro-1,2-dimethyl-3,5-diphenyl-4-hydroxy-1,2-diazolium hydroxide (373, R = R = Me, R = R = ph) shows a band (1546 cm" in dimethyl sulfoxide), which has been assigned as a carbonyl band. This absorption band, which is much lower than, for example, the sydnones (1) (vco 1750-1770 cm ) has been briefly considered in relation to the electronic characteristics of type A and type B meso-ionic heterocycles. However, the significance of this spectral difference must surely await more extensive comparison betweeen corresponding type A and type B heterocycles. The compound (373, R = R = Me, R = R = Ph) also shows a striking solvent dependence of its ul-traviolet/visible spectrum (Ama CjHg 447 McjSO 421 CHClj 410 Bu,OH 370 MeOH 345 Hp 325 nm). °... 

Diamonium pentachlorooxomolybdate(V) is an emerald green solid, stable in air. It is hygroscopic and should be stored in a stoppered vial in a desiccator. In concentrated HC1, a solution (> 10M) of the compound is green. In dilute HC1 (< 10M) the solution is greenish-brown or borwnish-red. The compound undergoes extensive ionic dissociation in aqueous solution. It is insoluble in benzene, chloroform, dichloromethane, and carbon tetrachloride. It is soluble (with decomposition) in ethanol, methanol, acetone, and pyridine a white solid of ammonium chloride precipitates from all these solutions immediately. The compound dissolves in dimethyl sulfoxide without decomposition. The electronic spectrum in 10 M HC1 contains the following absorptions 14,100(emax = 11), 22,500(emax = 10), 28,200(emax = 570),... 

A thiochroman-fused fullerene shows an absorption band at 441 nm in hexane which is characteristic of a 1 1 cycloadduct of It is shifted to 435 nm in the derived sulfoxide <1995TL6899>. The bands associated with 1,2-bis(thioxanthen-9-ylidene)ethene 237 are red shifted by 40-70 nm in its 1 1 complex with 0 in keeping with the interaction between the 7i-systems of the component parts. The IR spectrum is essentially a combination of the spectra of the two individual molecules. In the crystal, layers of Cgo alternate with layers of the alkene <2005MI711>. 

It was found that formation of the 6-cyclodextrin inclusion complex improved the compound solubility from less than 0.5 mg/mL to 160 mg/mL, eliminating the formulation problems associated with solubility concerns [65]. Although retinoic acid does exhibit intrinsic CD when dissolved in dimethyl sulfoxide, the CD spectrum is drastically upon formation of the cyclodextrin inclusion complex (see Figure 10). That CD can be measured in the absorption bands located at 350 and 400 nm can be taken as evidence that it is the conjugated sidechain of the retinoic acid solute which becomes included in the cavity of the cyclodextrin host system. 

Phthalocyaninato(2-)] iron(II) is a dark blue, thermally stable solid that can be sublimed in vacuo at 300°. It is very soluble in pyridine, giving deep blue solutions of the bis(pyridine) adducts. It also forms an unstable purple hexaaniline adduct when dissolved in aniline. It is soluble in concentrated sulfuric add and dimethyl sulfoxide (slightly) but is insoluble in most other organic solvents. The iron(II) complex, unlike the corresponding iron(II) porphines, is relatively stable toward oxidation to the iron (III) state. The electronic spectrum shows the following absorption bands (1-chloronaphthalene solution) 595 (e = 16,000), 630 (e = 17,000), 658 (e = 63,000) (pyridine solution) 333 (e = 45,000), 415 (e = 15,000), 395 (e = 2000), 658 nm (e = 8000). 

Dichloro(l,5-cyclooctadiene)platinum(II) is a white, air-stable solid. The compound is slightly soluble in solvents such as chloroform, acetic acid, sulfolane (tetrahydrothiophene 1,1-dioxide), and nitromethane. It decomposes slowly upon dissolution in dimethyl sulfoxide. The p.m.r. spectrum of the compound in chloroform shows resonances at 4.38r, /pt H = 65 Hz., for the olefinic protons and 7.29-r for the methylene protons. The infrared spectrum in Nujol has strong absorption maxima at 1334, 1179, 1009, 871, 834, and 782 cm.-1. 

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