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Theoretical Consideration Of Solubility
Published in A. L. Horvath, Halogenated Hydrocarbons, 2020
In subsequent articles by Kier and co-workers Kier, Murray, et al., 1975; Kier, Hall, et al., 1975; Hall et al., 1975; Murray et al., 1975, 1976; Kier et al., 1976; Di Paolo and Kier, 1977; Kier and Hall, 1976a, b, 1977a, 1978, 1979; Hall and Kier, 1977a, b, 1978a, b; Kier et al., 1977; Cammarata, 1979; Di Paolo et al., 1977, 1979; Gupta and Singh, 1979), the molecular conncetivity index was used to correlate cavity surface area, molecular polarizability, molar refractivity, parachor, anesthetic potency, boiling point, partition coefficient, biological activity, density, minimum inhibitory, minimum killing concentration, electron density, odor of molecule, solubility in water, and other properties. The various methods have been compiled and described in a book by Kier and Hall (1976b).
Intermolecular Force Parameters
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Bogdan Bumbăcilă, Mihai V. Putz
QSAR/QSPR researchers are trying to establish new equations which are correlating phyisico-chemical parameters of the molecules (induced by their intermolecular forces) with their properties/activities. For example, molar refractivity, refractive index, and electronic parameters have been used extensively, but the first study which correlated the surface tension with dissociation constants was Thakur’s study. He showed that the surface tension can be successfully used to model the dissociation constant of some sulfonamide drugs. The dissociation constant pKa depends upon the polarity and the intermolecular forces. For a maximum activity, the sulfonamides should have a proper pKa, for penetrating in vivo membranes and best binding abilities to their target enzyme. These abilities depend upon their protonated/unprotonated form dissociation constants, expressed as pKa (Thakur, 2005).
Fundamental Light–Tissue Interactions: Light Scattering and Absorption
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Tissue structure and refractive index are interlinked. Consider several liquid media with different refractive indices. The Gladstone–Dale equation allows one to calculate the refractive index of the mixture, nn=1+ρ∑iαimi,where ρ is the density (typically in g/cm3) of the mixed medium, the liquid components are mixed in mass fractions mi, and αi are refractive index increments of the pure components (sometimes referred to as molar refractivity) and, in our chosen units, in cm3/g. This relationship stems from a physical principle that it is the electron density of molecules within a medium that determines its refractive index. The Gladstone–Dale equation was formulated in 1864 and is used for many practical applications today. For example, the Brix refractometer determines the alcohol content of a water-alcohol mixture by means of measurement of the index of refraction of the mixture.
A descriptor-based analysis to highlight the mechanistic rationale of mutagenicity
Published in Journal of Environmental Science and Health, Part C, 2021
Domenico Gadaleta, Emilio Benfenati
For example, ATSC3m, ATSC4m, ATSC1m (centered Broto-Moreau autocorrelation descriptors), ChiA_B(m) (average Randic-like index from Burden matrix) and GATS1m (Geary autocorrelation of lag 1) are all descriptors weighted by mass and show high values for bulky chemicals. Eta_sh_x is the summation of α values of the vertices that are joined to four other non-hydrogen atoms. It gives a measure of molecular shape50 with particular reference to sp3 systems and bulky groups. Analogously, P_VSA_MR_5 is a P_VSA-like descriptors that is weighted on molar refractivity. Molar refractivity is related to the size and the total volume of the molecule.54–56X5Av is a connectivity index that accounts for various information about molecular volume, surface area, number of branches and heteroatoms.57
Mononuclear copper(I) complexes with triphenylphosphine and N,N′-disubstituted thioureas: synthesis, characterization, and biological evaluation
Published in Journal of Coordination Chemistry, 2018
Syed Ishtiaq Khan, Inayat Ali Khan, Amin Badshah, Fouzia Perveen Malik, Saira Tabassum, Ikram Ullah, Davit Zargarian, Muhammad Khawar Rauf
A number of steric descriptors were calculated for the comprehension of macroscopic interactions. Electronic descriptors cannot be calculated because of the presence of Cu – a heavy metal. An important steric descriptor is molar refractivity (MR) which is an extent of the total polarizability of a mole of a substance. As evident from Figure 8 direct correlation of the binding strength with the MR was observed implying increase of binding strength with an increase in the molar refractivity of the compound.