Spectroscopic correlations

Yang JS, Hwang CY, Hsieh CC et al (2004) Spectroscopic correlations between supermolecules and molecules. Anatomy of the ion-modulated electronic properties of the nitrogen donor in monoazacrown-derived intrinsic fluoroionophores. J Org Chem 69 719-726... 

It should be noted that the above treatment of errors does not take into account the effects of any systematic errors in the experimental heats, which might arise, for example, from solvent effects or from the fact that some of the heats were taken from spectroscopic correlations. 

Haloform reaction, 237, 296 Halogenation alkanes, 300, 323 alkenes, 179,186, 313 benzene, 138,316 ketones, 295 Hammett equation, 362 additional parameters, 374, 388, 395 derivation of, 362 deviations from, 375 empirical nature of, 395 implications of, 394 reaction pathway, and, 375 solvent effects and, 388 spectroscopic correlations, 392 standard reaction for, 362, 395 steric effects and, 361, 383 thermodynamic implications of, 394 Hammett plots, 359 change in rate-limiting step and, 383 change in reaction pathway and, 378... 

The values for the redox potential for the couple M3 + /M2+ have been estimated57 using a simple ionic model and available thermodynamic data. The results (Table 2) correlate closely with the ionization potentials for the M2+ ions, and are in good agreement with both chemical observations and other estimates obtained by spectroscopic correlations. Irreversible oxidation of terbium(m) to terbium(iv) in aqueous K2C03-K0H solutions has been observed electrochemically 58 the discovery of an intermediate of mixed oxidation state explains partly the reduction behaviour of terbium(iv) deposits. Praseodymium(iv) and terbium(iv) have also been detected in nitrate solutions. 

The low-temperature MCD and absorption titration studies (Figure 10) have determined that azide binds to both the type 2 and type 3 centers with similar binding constants. A series of chemical perturbations and stoichiometry studies have shown that these effects are associated with the same azide. This demonstrates that one N3 bridges between the type 2 and type 3 centers in laccase. These and other results from MCD spectroscopy first defined the presence of a trinuclear copper cluster active site in biology (89). At higher azide concentration, a second azide binds to the trinuclear site in laccase. Messerschmidt et al. have determined from X-ray crystallography that a trinuclear copper cluster site is also present in ascorbate oxidase (87, 92) and have obtained a crystal structure for a two-azide-bound derivative (87). It appears that some differences exist between the two-azide-bound laccase and ascorbate oxidase derivatives, and it will be important to spectroscopically correlate between these sites. 

Since the stmctures and spectroscopic correlations for both oxy and red forms of He, Co, and Tyr are well understood, much of the future synthetic modeling work will focus on the reactivity of CU2O2 species. Tyr activity, o-phenol hydroxylation, seems to occur via an electrophihe aromatic substitution, but the broader scope of reaction for side-on /r- -peroxodicopper(II) complexes should be further explored. Much remains to be accomphshed in determining the detailed mechanism of catechol oxidase catalysis (i.e. HAT vs. PCET). The differential reactivity of peroxo versus bis-/u.-oxo tautomers is still largely unknown. Although there is as yet no... 

There are very few experimentally-recorded spectroscopic data for COBrF, and only one publication [1596] exists in which the spectroscopic properties of COBrF have been studied for their own sake. Apart from the recording of a F n.m.r. spectrum and a mass spectrum [1163], the remaining spectroscopic studies of COBrF have been confined to the recording of its infrared spectrum [1596], and to the derivation of spectroscopic correlations with other members of the carbonyl halide series [604,864,1860],... 

In light of recent advances in solid state Hg NMR, Raman, IR, EXAFS, and electronic spectrocopies summarized here, Hg(II) complexes can no longer be considered as spectroscopically silent. A formidable barrier to establishing reliable spectroscopic correlations with the coordination environment still exists because of the small number of well characterized small molecule complexes. Solution Hg NMR, vibrational, and electronic spectroscopies can distinguish complexes with a coordination number of 2 from those with CN = 3 or 4. None of these techniques can readily distinguish between three and four coordination however. Recent advances in solid-state Hg NMR spectroscopy unequivocally demonstrate that Hg-SR complexes with a primary coordination number of three or four can be readily distinguished. 

A correction to earlier work on the addition of formaldehyde aminals and amino-acetals to bis(trifiuoromethyl)keten has appeared, and shows that addition in fact occurs to the carbon-carbon double bond and not to the carbonyl group as thought earlier. This came to light as a result of spectroscopic correlations established during synthetic work on keten acetals and related compounds, most of which were not derived from the keten itself. ... 

The diastereomeric purities of 2a were determined by capillary gas chromatography or H-NMR studies (quantitative determination of the molar ratio 2a/2b). The enantiomeric purities of 2a were established, affer derivatization with (S)-2-methoxy-2-(trifluoromethyl)-2-phenylacetyl chloride [(5)-MTPA-Cl], by H- or F-NMR studies [quantitative determination of the molar ratio (Si5, C7 )-2a/(SiR,CS)-2a]. The enantiomeric purities of 3a (after hydrolytic conversion into 2a) were determined analogously to those of 2a. The absolute configurations at the SiCH(OH)C carbon atoms of the enantiomers of 2a were established, after derivatization with (5 -MTPA-Cl, by the NMR-spectroscopic correlation method described in [7]. The relative configurations of 2a and 2b were assigned by comparison with the diastereoisomers of 1-methyl-1-phenyl-l-sila-2-cyclohexanol (in this context, see [8]). 

What is the bcisis for using spectroscopic methods such as QELSS, FRAP, FRS, or FCS to measure Dg or Dp In each case physical theory links the spectroscopic correlation function to fluctuations in microscopic variables that describe the liquid. For QELSS, the spectrum is determined [16] by the field correlation function t) of the scattered light, which mses from the scattering molecules via... 

Bruno TJ, Paris S (2005) CRC handbook of fundamental spectroscopic correlation charts. CRC press, Boca Raton, FL... 

From forensics and security to pharmaceuticais and environmentai appiications, spectroscopic detection is one of the most cost-effective methods for identifying chemicai compounds in a wide range of discipiines. The CRC Handbook of Fundamental Spectroscopic Correlation Charts provides a coiiection of spectroscopic information and unique correiation charts for use in the interpretation of spectroscopic measurements. 

This book presents fundamental charts that are needed on a general, day-to-day basis. The CRC Handbook of Fundamental Spectroscopic Correlation Charts is an ideal laboratory companion for students and professionals in academic, industrial, and government labs. 

In both of those editions, spectroscopic correlations are presented essentially in tabular form. It is onr conviction, however, that for spectroscopic data, correlation charts are far more easily used than tables. This is especially true of scientists and students who must make use (occasional or freqnent) of spectroscopic methods, while their own areas of specialization may lie elsewhere. We have therefore developed a set of fundamental correlation charts that target the same audience as the tabnlar format adopted in CRC Handbook of Basic Tables for Chemical Analysis. The exception wonld be the tables that we present here for mass spectrometry, a technique that does not lend itself to graphical presentation of data. It is nevertheless important to have data for this important techniqne covered here, since often multiple techniques, including mass spectrometry, are used for analyses and strnctnral determinations. 

Since only a few standard aqueous electrode potentials °(Ln /Ln ) have been determined electrochemically, others have been estimated [e.g., (Dy /Dy ) (Morss and Fahey 1976, Morss and Spence 1992)] from calorimetric measurements on their dichlorides or from spectroscopic correlations. The only experimental values of °(An /An " ) are from radioelectrochemical measurements on Fm-No (David 1986a) and coprecipitation studies (Mikheev 1988,1992). Spectroscopic correlations of (An /An ) have also been made (section 3.4). These reduction potentials have been assessed for the rare earths (Morss 1985), for the lighter actinides (Martinot and Fuger 1985), and for the heavier actinides (David 1986a, Morss 1986). With the exception of uranium, neptunium and plutonium species [(Fuger 1992, table 1), discussed in section 2.4.1] and No + (discussed in section 2.4.1), these potentials are still valid. We note that the (An /An) values depend on the S°[An (aq)] which are referenced to a value for Pu (aq) that is based in part on experiment but also required estimation of S°[PuClj 6H20(s)]. 

The fluorocarbon groups in (20) are assigned the trans disposition in view of the single strong i.r. carbonyl band, and it is argued that the three weak bands also observed for each compound arise from the lack of axial symmetry in the fluorocarbon groups, rather than from the presence of c -isomers. The stereochemistry about the double bond is firmly based on F n.m.r. spectroscopic correlations. 

The above analysis, shared by many spectroscopists in the field of small molecules, can be further expanded when vibrational spectroscopy is considered in the field of polymers and macromolecules in general. The wiggling of polymers adds new flavor to physics and chemistry. The translational periodicity of infinite polymers with perfect stmcture generates phonons and collective vibrations which give rise to absorption or Raman scattering bands that escape the interpretation based on the traditional spectroscopic correlations. The concept of collective motions forms the basis for the understanding of the vibrations of finite chain molecules which form a nonnegligible part of industrially relevant materials. On the other hand, real polymer samples never show perfect chemical, strereochemical, and conformational structure. Symmetry is broken and new bands appear which become characteristic of specific types of disorder. 

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