Organic compounds physicochemical characteristic

The concentration gradient. This is normally in the direction external to internal relative to the cell or organism. The rate of diffusion is affected by certain factors it is proportional to the concentration gradient across the membrane the area and thickness of the membrane and a diffusion constant, which depends on the physicochemical characteristics of the compound in question. This relationship is known as Fick s Law ... 

The search for relationships among the dynamic and equilibrium properties of related series of compounds has been a paradigm of chemists for many years. The discovery of such unifying principles and predictive relationships has practical benefits. Numerous relationships exist among the structural characteristics, physicochemical properties, and/or biological qualities of classes of related compounds. Perhaps the best-known attribute relationships are the correlations between reaction rate constants and equilibrium constants for related reactions commonly known as linear tree-energy relationships (LFERs). The LFER concept led to the broader concepts of QSARs, which seek to predict the environmental fate of related compounds based on correlations between their bioactivity or physicochemical properties and structural features. For example, therapeutic response, environmental fate, and toxicity of organic compounds have been correlated with... 

Traditional approaches for natural product screening in drug discovery involve the testing of crude extracts obtained from microbial fermentation broths, plants, or marine organisms. When activity above a certain level is detected, active components are isolated and purified for identification. This process is often time consuming where the physicochemical characteristics of the active components are determined, known compounds are identified (dereplication), and the novel compounds are scaled-up for more detailed investigation. 

Aromaticity has been long recognized as one of the most useful theoretical concepts in organic chemistry. It is essential in understanding the reactivity, structure, and many physicochemical characteristics of heterocyclic compounds. However, there is no precise quantitative definition of aromaticity that is universally acceptable. Aromaticity is usually... 

One of the most important physicochemical parameters associated with oral absorption, central nervous system (CNS) penetration, and other pharmacokinetic parameters is lipophilicity of organic compounds, which determines distribution of a molecule between the aqueous and the lipid environments. The lipophilicity in the form of LogP was included in Lipinski s rule of five as one of the major characteristics of drug-like organic molecules. It was stated that LogP should be not more than five for drug candidates to have a good... 

An ionophore, from the Greek words ion and/ero (carry), is a compound (organic or organometallic) which can selectively and reversibly coordinate to a specific ion and can thus, based on differences in Gibbs energy, transport the ion from the aqueous solution into a membrane. Up-to-date knowledge in the area of ionophores suggests that there are some very important physicochemical characteristics that a compound must have in order to be a candidate for use as an ionophore in ISEs. The most important of these are ... 

All reactions of organic compounds on solid catalysts are accompanied by the formation of heavy by-products, the so-called coke, which is deposited on the surface of the catalyst and provoke deactivation (1-2). Coke is formed inside the pores and/or the external surface of solid catalysts, and is the primary cause of their deactivation (3). Product composition, coke rate and coke composition are dependent on various parameters, such as reaction temperature (4-5), nature of the reactants (6), and the physicochemical characteristics of the zeolites, such as acidity (7) and pore structure (8-9). 

Retention indices of various systems sometimes are considered as different characteristics of chemical compounds. However, it is rational to neglect the differences in these parameters for the same compounds, measured in unequal conditions (in various laboratories) with the same stationary phases. Statistical processing of all of them (so-called randomization) gives averaged RI values (together with corresponding standard deviations), which can be considered as GC constants of organic compounds, as well as their other physicochemical parameters (Table 1). 

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