Polarization dynamic

Van der Zwan G and Hynes J T 1982 Dynamical polar solvent effects on solution reactions A simple continuum model J. Chem. Phys. 76 2993-3001... 

Kaptein R and Oosterhoff J L 1969 Chemically Induced dynamic polarization II (relation with anomalous ESR spectra) Chem. Phys. Lett. 4 195-7... 

Palm, K., Luthman, K., Ungell, A.-L., Strandlund, G., Beigi, F., Lundahl, P., Artursson, P. Evaluation of dynamic polar molecular surface area as predictor of drug absorption comparison with other computational and experimental predictors. J. Med. Chem. 1998, 41, 5382-5392. 

PSA. Hence, we only mention here that the definition of PSA is similar to that of Na and N. Thus, PSA possesses the same disadvantages when compared to thermodynamic H-bond descriptors. In fact, it has been estimated that there is a strong linear relationship between the calculated static PSA and the calculated dynamic polar surface [32, 33]. A further possible simplification using only the number of H-bond forming atoms and PLS statistics was proposed [35]. Excellent correlahons of PSA with the number of H-bond donors and acceptors were published [35, 36]. 

Iwata K, Ozawa R, Hamaguchi H (2002) Analysis of the solvent- and temperature-dependent Raman spectral changes of S1 trans-stilbene and the mechanism of the trans to cis isomerization dynamic polarization model of vibrational dephasing and the C=C double-bond rotation. J Phys Chem A 106 3614—3620... 

Virtually all known acyclic carbozirconation reactions involve activation through dynamic polarization or ate complexation as shown in Scheme 1.7. Some of the representative examples are shown in Scheme 1.43. The reaction of allylzirconocene derivatives [151] shares similar regiochemical features with the Zr-catalyzed allylalumination [22,152] and appears to be mechanistically closely related. 

Kelder et al. [25] also explored the role of PSA as a determinant for the transport of drugs through the BBB. Initially, they calculated and correlated the PSA of 45 drug molecules with their known brain-penetration data. A linear relationship was obtained between brain penetration and dynamic polar surface area (DPSA) as shown in Eq. 34 ... 

Closing naphthyl ring. The induced dipole moment is then chirally disposed in relation to the inducing NH2 dipole moment. This mechanism, referred to as the dynamic polarization model (45), is shown to explain most of the observed VCD intensity in the synunetric NH2 stretching mode, >>nh2- The anisotropy ratio for this VCD band is ca. 10. Since an NH. . . x type hydrogen bond is possible in this molecule, a description based on vibrationally induced charge flow (currents) may also be riuitfiil, similar to that proposed for a-phenyleth-ylamine. Sect. FV-B-2. 

Picosecond Raman measurements have led to the proposal of a dynamic polarization model." In this model, 5i tS undergoes reversible changes in vibrational frequencies that are induced by solvent fluctuations. The mixing of a perturbing state with interconverts carbon-carbon double bonds with single bonds that leads S tS near the vertical geometry to proceed along the pathway for isomerization. 

Single-bilayer DODAC (6) vesicles Magnetite particles prepared in situ in vesicles from Fe2+/Fe3+ and OH" Static and dynamic polarized and depolarized light scattering and static and time-resolved dichroic anisotropy, as well as conventional magnetization vs applied magnetic field determinations were used for characterization 794... 

Coherent dissociation Geminate recombination Dephasing Proton transfer Electron transfer Vibrational relaxation 8arrierless reactions Bimolecular reactions Ionic reactions Solvation dynamics Friction dynamics Polarization (kerr)... 

G. R. Lawler, Chemically Induced Dynamic Polarization (CIDNP). II. The Radical-Pair Model," Accfs. Chem. Res. 5, 25 (1972). 

The technique most recently introduced to study radical cations is chemically induced dynamic polarization (CIDNP), a nuclear resonance method based on the observation of transient signals, substantially enhanced in either absorption or emission. These effects are induced as a result of magnetic interactions in radical or radical ion pairs on the nanosecond timescale. This method requires acquisition of an NMR spectrum during (or within a few seconds of) the generation of the radical ion pairs. The CIDNP technique is applied in solution, typically at room... 

In PI, the slow and fast indices are replaced by the subscripts or and el referring to orientational and electronic response of the solvent, respectively, while in PII the subscripts in and dyn refer now to an inertial and a dynamic polarization response of the solvent, respectively. 

PSAd, dynamic polar molecular surface area If specific capacity factor, for details see ref 55. 

In addition, the results of absorption studies for a series of (i-adrenoceptor blockers in vitro using Caco-2 monolayers and rat intestinal segments have been used to test new descriptors [55]. For this purpose, the authors calculated dynamic molecular surface properties considering all low-energy conformations. Molecular mechanics were used to consider the flexibility of the molecules, and the van der Waals volume (vdW) and water-accessible surface areas were also calculated (Table 4.18 and 4.19). When the dynamic polar vdW surface areas were used in regression analysis to describe cell permeability data obtained in Caco-2 cells and in rat ileum, excellent correlations were obtained (r2 = 0.99 and 0.92 respectively). 

However, these molecular modeling techniques, like molecular dynamics calculations and dynamic polar surface calculations, require expensive computer time. Hydrogen bond formation and molecular volume turned out to be the most important... 

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