Alkylamines correlation

The significance of the values calculated for the effective polarizability was first established with physical data, among them relaxation energies derived from a combination of X-ray photoelectron and Auger spectroscopy, as well as N-ls ESCA data53, 54). From our point of view, however, the most important applications of effective polarizability are to be found in correlating chemical reactivity data. Thus, the proton affinity (PA) of 49 unsubstituted alkylamines comprising primary, secondary and tertiary amines of a variety of skeletal types correlate directly with effective polarizability values (Fig. 22). 

Alkane carbon atoms satisfy the charge-NMR shift correlation [Eq. (6.8)]. With the alkylamines, things could be different because of a possible extra effect due to the presence of the nitrogen atom a-carbons should perhaps be compared only among themselves, and so should the /3- and y-carbons. The S-carbons, in contrast, which are sufficiently separated from the nitrogen center, could probably be treated as if they were part of an alkane. This point has been examined as follows for the —C 2—H2—NH2 motif, focusing on the dissociation and intrinsic bond energies, Dc Cp and sc Cp, respectively. 

The N-15 resonance shifts of alkylamines and nitroalkanes are expressed in ppm from HNO3, in methanol. Separate correlation lines are observed for mono-, di- and trialkylamines, namely... 

Coffander-iype Relationships Collander has studied partition coefficients in different alcohol-water systems [16]. He found that these partition coefficients are mutually correlated. For certain compounds containing one hydrophilic group, such as alkanols, alkanoic acids, alkanoates, dialkyl ethers, and alkylamines and selected compounds containing two, three, or four such groups, he reports the following equation ... 

Reviews by Gorte and coworkers [35, 36] deal with the adsorption complexes formed by strong and weak bases with acid sites in zeolites. They examine the adsorption enthalpies of a series of strongly basic molecules such as alkylamines, pyridines and imines. These workers also performed studies of the adsorption properties of weak bases, including water, alcohols, thiols, olefins, aldehydes, ketones and nitriles. They report a poor correlation between the differential heats of adsorption on H-MFl zeolites and the enthalpies of protonation in aqueous solutions, but a much better correlation with gas-phase proton affinities [37]. 

The electrochemical behaviour of the ribbed-functionalized iron(II) [65, 68] and ruthenium(II) [78] clathrochelates with alkylamine, thioaryl, thioalkyl, phenoxyl and crown ether substituents in a-dioximate fragments was characterized by E1/2 values for Fe3+/2+ and Ru3+/2+ couples (Table 37). The Tomes criterion values of most complexes exhibited reversible or quasi-reversible anodic processes. Moreover, the quasi-reversible oxidation processes are accompanied by the formation of insoluble products followed by passivation of the working electrode. The Ev2 values depend on the electron-donating properties of the substituents in the ribbed fragments. The correlations of E1/2 values for Ru3" 2+ and Fe + 2+ couples with these substituents Hammet s Opara constants were observed in Refs. 65, 68, and 78. These correlations are rather qualitative, but they enable one to conclude that ruthenium complexes are less sensitive to the change of substituents in dioximate fragments. There was no correlation between the Em values and the inductive Taft s (cr,) constants for substituents in dioximate fragments. 

In addition to the nucleophiles shown in Fig. 12, a number of a, oj-diaminoalkanes, both neutral and monoprotonated, show a similar correlation as alkylamines, but displaced by a factor of 10 upward (Bruice and Willis, 1965). Either these bases belong in a different class from alkylamines or their greater reactivity could be attributed to intramolecular general base or general acid facilitation. 

FIGURE 1. Correlation of scales for some common EPD/HBA solvents with solvatochromic comparison probe pairs with the Kamlet-Taft /3kt parameters. Circles pair 8/7, squares pair 1/2, and triangles pair 17/18 (empty symbols for alkylamines), all normalized with 0.00 for cyclohexane and 1.00 for HMPA... 

Similarly, as shown in Figure 3.21 (b), (c), (d), and (e), there exists an excellent linear correlation between the charge/volume of the charged species encapsulated in the framework and the charge density of the anionic framework for the anionic aluminophosphates with Al/P ratio of 1/2 directed by arylamines, the anionic aluminophosphates with Al/P ratio of 2/3 directed by cyclic amines, the layered anionic aluminophosphates with Al/P ratio of 3/4 and 4,6,8-net topological sheet structure directed by chain-shape alkylamines, and the layered anionic aluminophosphates with Al/P ratio of 3/4 and 4,6,12-net topological sheet structure directed by chain-shape alkylamines as well. 

In a series of Cr -alkylamine complexes with CrN skeletons, a correlation has been shown to exist between the radiationless transition rate and the number of active hydrogens attached to the donor atoms.The authors also report an expression that predicts the dependence of the non-radiative rates from the vibrational degeneracy and the displacement of the maximum frequency modes. 

In later work. Smith and coworkers [41a] found an interesting empirical correlation between the molecular mass, M, and the average charge, Zav, see Eq. (1.13), of starburst dendrimers. Starburst dendrimers are multibranched alkylamine polymers that have relatively rigid structures and are close to spherical, that is, with shapes resembling those of globular proteins. 

Lee et al. [174] have used microcalorimetry to measme the differential heats of adsorption of both a series of alkylamines and a series of substituted pyridines in H-ZSM-5. With few exceptions, the differential heats were approximately constant up to coverages close to the expected BrOnsted site concentration. The authors observed a strong correlation between gas-phase proton affinities and differential heats of adsorption of amine and pyridine bases but no useful correlation with aqueous base strengths, this contrast implying that the Hammett Ho value is probably not a meaningful description of zeohte acid strength. 

In another study, Lee et al. [174] have observed a strong correlation between gas-phase proton affinities and differential heats of adsorption of a series of alkylamines and a series of substituted pyridines in H-mordenite. 

Philippe, R. Delmas, G. Hong, P. N. Excess heats of tri-n-alkylamines and tetraalkyl tin compounds in linear and branched alkanes correlations of molecular orientations and steric hindrance effect Can. J. Chem. 1979,57, 517-525... 

Clearly, nitrogen shifts can be used as carbon shifts are. Thus there are substituent parameters for alkylamines, amino acids and peptides,ureas, amides, and so on, although two-dimensional correlation spectra are... 

The aquation kinetics of the chloropentaamminecobalt(III) ion in water-ethanol mixtures has been studied. The rate constants correlate well with the Grunwald-Winstein Y parameter and with the dielectric constant of the medium. The data supports a D mechanism for the reaction. The loss of chloride from the complexes cw-[Co(en)2(NH2CH2CH20H)Cl] and cw-[Co(en)2(NH2(CH2)3 0H)Cl] has been studied in aqueous ethyleneglycol at 40-65 °C in acidic media and at 20-35 °C in basic media.The rate constants decreased linearly with the increasing mole fraction of the cosolvent. The loss of chloride resulted in the formation of the chelated amino-alcohols as the main product. The observed solvent isotope effect (A h2oAd2o) = 112 at 50 °C, [HCIO4] =0.01 moldm for chloride release is lower than the value reported for the aquation of the cw-[Co(en)2(alkylamine)Cl] complexes (1.38-1.44). This result may indicate the lack of direct solvent intervention in the act of substitution at the cobalt(III) center, as expected for a true intramolecular reaction. 

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