INDEX protonation

J. Rams, F. Agullo-Rueda, J.M. Cabrera, Structure of high index proton exchanged LiNb03 waveguides with undegraded nonlinear optical coefficients, Appl. Phys. Lett. 71. 3356-3358 (1997). 

As a measure of the stereoregularity, an index EQ-H% was defined as the precent of the equatorial acetal protons to the total acetal protons. Figure 2 illustrates the temperature dependence of EQ-H% s of the polymer obtained in toluene (A), methylene chloride (B), and 1-nitropropane (C). No significant difference is observed at... 

Tervalent organophosphorus compounds containing one single P-N bond with the valency of each atom saturated by protons or carbons (but no other heteroatoms) have been known since their discovery by MichaeUs more than one century ago [ 1 ] and named indistinctly as aminophosphanes, phosphanamines, phosphazanes, or phosphinous amides. This last chemical nomenclature is the one used by the Chemical Abstracts Service (CAS) for indexing these compounds and is also the one that best delimits the scope of this review those species derived from the parent H2P-NH2 (phosphinous amide in CAS nomenclature) by partial or total substitution of protons by hydrocarbon radicals (Table 1). 

The model has the advantage that it requires only a simple table eontaining the polarity index P and selectivity group for a number of solvents (Table 4.2). The model is based on Snyder s elassifieation of solvents [41,42] aeeording to their eharaeteristies to internet as proton aeeeptors (xj, proton donors (x, or dipoles (xj. 

The solvent triangle classification method of Snyder Is the most cosDBon approach to solvent characterization used by chromatographers (510,517). The solvent polarity index, P, and solvent selectivity factors, X), which characterize the relative importemce of orientation and proton donor/acceptor interactions to the total polarity, were based on Rohrscbneider s compilation of experimental gas-liquid distribution constants for a number of test solutes in 75 common, volatile solvents. Snyder chose the solutes nitromethane, ethanol and dloxane as probes for a solvent s capacity for orientation, proton acceptor and proton donor capacity, respectively. The influence of solute molecular size, solute/solvent dispersion interactions, and solute/solvent induction interactions as a result of solvent polarizability were subtracted from the experimental distribution constants first multiplying the experimental distribution constant by the solvent molar volume and thm referencing this quantity to the value calculated for a hypothetical n-alkane with a molar volume identical to the test solute. Each value was then corrected empirically to give a value of zero for the polar distribution constant of the test solutes for saturated hydrocarbon solvents. These residual, values were supposed to arise from inductive and... 

Evaluation of the only appropriate Fukui function is required for investigating an intramolecular reaction, as local softness is merely scaling of Fukui function (as shown in Equation 12.7), and does not alter the intramolecular reactivity trend. For this type, one needs to evaluate the proper Fukui functions (/+ or / ) for the different potential sites of the substrate. For example, the Fukui function values for the C and O atoms of H2CO, shown above, predicts that O atom should be the preferred site for an electrophilic attack, whereas C atom will be open to a nucleophilic attack. Atomic Fukui function for electrophilic attack (fc ) for the ring carbon atoms has been used to study the directing ability of substituents in electrophilic substitution reaction of monosubstituted benzene [23]. In some cases, it was shown that relative electrophilicity (f+/f ) or nucleophilicity (/ /f+) indices provide better intramolecular reactivity trend [23]. For example, basicity of substituted anilines could be explained successfully using relative nucleophilicity index ( / /f 1) [23]. Note however that these parameters are not able to differentiate the preferred site of protonation in benzene derivatives, determined from the absolute proton affinities [24],... 

We will use the so called TM1 model which is given by the following Lagrangian, describing coupling of the nucleon field to the non-linear sigma, omega and rho meson fields (index i p, n denotes protons or neutrons),... 

The most important route to 1-acylaminoanthraquinones involves reaction of 1-aminoanthraquinone with acid chlorides in an organic solvent. Reaction of 1-aminoanthraquinone with benzoylchloride in nitrobenzene at 100 to 150°C affords 1-benzoylaminoanthraquinone, a yellow pigment which is registered as Colour Index Constitution No. 60515. The reaction may also be performed in the presence of a tertiary amine, which acts as a proton acceptor ... 

Another example of the use of transition state pKa values has been provided by Pollack (1978). From the rate constants for the decarboxylation of substituted a,a-dimethylbenzoylacetic acids ([37] — [38]) and their anions, he calculated pK for reaction of the acids (Table A6.2). The values vary significantly with the phenyl substituent (p = +1.7), much more so than the p/(a values of the substrate acids (p = +0.2). This difference is consistent with the proton being much closer to the phenyl group in the transition state than in the initial state, and it may even denote a relatively late transition state (Pollack, 1978). However, from the pKa values of the reactant acids (approximately 3.4), the transition states (approximately 4.4), and the enol product (11.8) (Pruszynski et al., 1986), the Leffler index... 

Fields et al. 33) examined the closely related bis (trifluoromethyl) phosphine (Table 14) and found a similar increase in Vp.H with increasing polarity of the solvent. They noted a correlation between /P H and the proton chemical shift (confidence limit of the correlation coefficient was 99.9 %). Again hydrogen bonding was suggested as the principle causative factor since correlations with dielectric constant or refractive index were not found. The two-bond 2/P F was noted to decrease while the three-bond 3/H F coupling constant was solvent invariant (vide infra). 

One approach refers to local charge densities [188] the other one uses localization energies as a reactivity index [189]. In any event, the inductive effect of the methylene group, formed in the first protonation step, has to be taken into account if two sites provide comparable reactivity indices. 

Since the monoisotopic signal is the protonated ion, the elemental composition for the API in the counterfeit tablets was therefore determined as C8lTj502N7S3. A computerized search of The Merck Index using the elemental formula suggested the unknown compound to be Famotidine, an active pharmaceutical ingredient widely used in over-the-counter antiulcerative medicine. 

V.V. Atuchin, I. Savatinova, C.C. Ziling, High refractive index metastable phases in proton exchanged H LiTa03 optical waveguides, Mat. Lett. 46, 189-192 (2000). 

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