Electrostatic and lipophilic

The same procedure is used to compute cross-correlation coefficients C, which correlate two different properties, e.g., electrostatic and lipophilic single atom parameters. Every C value describes typical distances of regions in a molecule with... 

Hasegawa, K., Matsuoka, S., Arakawa, M. and Funatsu, K. (2003) Multi-way PLS modeling of structure-activity data by incorporating electrostatic and lipophilic potentials on molecular surface. Comp. Biol. Chem., 27, 381-386. 

The aligned conformations were compared again using Asp. Through the Tsar interface, molecules can be compared by shape and electrostatic and lipophilic properties. Thus 108 columns of data were generated by... 

The CoMSIA analysis using steric, electrostatic, and lipophilic fields as descriptors gave a model with (f of 0.873 and of 0.954. The CoMSIA steric, electrostatic, and lipophilic fields explained the variance of 8.8, 40.9 and 50.2 %, respectively. This indicated that the hydrophobic interaction was a major factor to explain the field properties of the alkylphosphonates lo. Further attempts to combine the hydrogen bond fields with the standard steric, electrostatic, and lipophilic fields did not lead to any significant improvement = 0.869, = 0.952). Indeed,... 

The electrostatic and steric effects can be combined to stabilize nanoparticles in solution. This type of stabilization is generally provided by means of ionic surfactants such as alkylammonium cations (Scheme 9.3). These compounds bear both a polar head group which is able to generate an electrical double layer, and a lipophilic side chain which is able to provide steric repulsion [14, 15]. 

Since CEC is a hybrid technique, the differential migration of analytes through the stationary phase bed will generally involve lipophilic, electrostatic, and electrophoretic processes between the analytes and the stationary and mobile phases. Consequently, the applied voltage and electrical field strength and the mobile phase properties such as pH, buffer concentration, ionic strength, temperature, and the organic content will all affect the separation. For a detailed discussion, also refer to reference 10. 

The major hurdle to overcome in the development of 3D-QSAR models using steric, electrostatic, or lipophilic fields is related to both conformation selection and subsequent suitable overlay (alignment) of compounds. Therefore, it is of some interest to provide a conformation-ally sensitive lipophilicity descriptor that is alignment-independent. In this chapter we describe the derivation and parametrization of a new descriptor called 3D-LogP and demonstrate both its conformational sensitivity and its effectiveness in QSAR analysis. The 3D-LogP descriptor provides such a representation in the form of a rapidly computable description of the local lipophilicity at points on a user-defined molecular surface. 

Thomlinson [78] was the first chromatographer to point out that the classical electrostatic ion-pair concept did not hold for IPRs that were usually bulky hydrophobic ions he also emphasized that in the interfacial region between the mobile and the stationary phases, the dielectric constant of the medium is far lower than that of the aqueous phase. Chaotropes that break the water structure around them and lipophilic ions that produce cages around their alkyl chains, thereby disturbing the ordinary water structnre, are both amenable to hydrophobic ion-pairing since they are both scarcely hydrated. The practical proof of such ion-pairing mode can be found in References 80 and 81 many examples of such pairing modes are reported in the literature [79-86],... 

Three-dimensional pharmacophore patterns Target interaction sites (hydrogen bonds, electrostatic or lipophilic interactions, etc.). Similarities between different chemical classes and scaffolds can be recognized. 10 to 10 s... 

Ion interaction. This suggestion is based neither on ion pair or ion exchange phenomena, though the lipophilic ions are adsorbed onto the surface but are associated with a primary ion giving an electrical double layer. The analyte then interact dynamically with this double layer by both electrostatic and van der Waal s type forces. 

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