Correlation, property with molecular structure

The study of aqueous solutions of surface-active agents is interesting from both research and application points of view [1-13]. This chapter attempts to correlate the tribological properties with molecular structure, surface activity, and micelle and LLC formation ability both in the surface phase and in the bulk phase. The physicochemical properties are determined under static conditions, and relating them to dynamic conditions is difficult. Pressures, relative movement, and dissipation of energy in the form of heat aU occur under friction conditions. 

The objective of this work is to synthesize a series of acetylene terminated aryl-ether systems for the purpose of correlating their thermal and thermal mechanical properties with molecular structure. 

Correlation of Explosive Properties with Other Parameters "The Relationship between Performance and Constitution of Pure Organic Explosive Compounds is the subject of a review by Lothrop Handrick (Ref 1). Price (Ref 2) has reviewed the "Dependence of Damage Effects upon Detonation Parameters of Organic High Explosives , and Martin Yallop (Ref 3) have reported on "The Correlation of Explosive Power with Molecular Structure ... 

Tannins are used in medicine primarily because of their astringent properties, which are due to the fact that they react with the proteins of the layers of tissue with which they come into contact. Tannins are known to tan the outermost layer of the mucosa and to render it less permeable and more resistant to chemical and mechanical injury or irritation however, the correlation between the molecular structures of tannins and the astringent/antiulcer activity is not known. 

Alternatively, calculated molecular properties from 3D molecular fields of interaction energies represent a valuable approach to correlate 3 D molecular structures with physicochemical and pharmacodynamic properties. In contrast, their use in correlations with pharmacokinetic properties is still poorly explored and exploited. The rather new VolSurf approach [5-7] is able to compress the relevant information present in 3D maps into a few descriptors characterized by the simplicity of... 

They constitute the most important class of experimental measurements and play a fundamental role as —> molecular descriptors both for their availability as well as for their interpret-ability [Exner, 1966 Lyman, Reehl et al., 1982 Reid, Prausnitz et al, 1988 Horvath, 1992 Abraham, 1993c Baum, 1997 Lide, 1999 Reinhard and Drefahl, 1999]. Physico-chemical properties are used both as the molecular properties to be correlated with molecular structure in QSPR modeling and as the molecular descriptors when searching for relationships with biological activities. Physico-chemical properties are constitutive parts of volume descriptors, —> electric polarization descriptors, spectra descriptors, chromatographic descriptors, and so on. Combinations of physico-chemical properties are largely used in the definition of environmental indices. Other important physico-chemical properties are the so-called technological properties useful to characterize materials. 

The quantitative structure-activity and structure-property relationships (QSARs/ QSPRs) have become efficient tools to study complex chemical and biochemical systems. In principle, once a correlation between the molecular structure and activity/ property is found, any number of compounds, including those not yet synthesized, can be readily screened on the computer in order to predict the structures with the desired properties. Subsequently, the respective chemical compounds can be synthesized and tested in the laboratory. Thus the QSAR/QSPR approach conserves resources and accelerates the process of development of new drugs, materials, etc. In addition to the structure predictions, the QSAR/QSPR models often help to understand the physical nature of the processes and interactions behind the property or activity studied. 

Various acrylate copolymers with complex architectures have beensynthesized via atom transfer radical polymerization. A strong correlation between the molecular structure and composition of the copolymers and their thermo-mechanical behavior have been found. This suggests a facile route for creating new advanced materials with tailored properties. 

AN EVALUATION OF THE MECHANICAL PROPERTIES OF ADHESIVES AT CRYOGENIC TEMPERATURES AND THEIR CORRELATION WITH MOLECULAR STRUCTURE HERTZ J GENERAL DYNAMICS/ASTRONAUTICS SAN DIEGO CALIF DDC... 

The authors correlated properties of LDPE with molecular structure, characterized by long-and short- chain branching (LCB and SCB, respectively) and the molecular weight (MW)... 

It is interesting to mention that there is a correlation between the molecular structures of alkanes and some of their physical properties. By correlating the number of carbon atoms in simple alkanes with the melting points of the same compounds we observe that the molecules with odd numbers of C-atoms and those with even numbers of C-atoms exhibit different correlation curves. 

An important goal of these new experiments is to develop a link between the physical properties and molecular structures of different nitramines and their combustive behavior. The motivation of the work on the condensed phase is to obtain a better understanding of the physical processes and reaction mechanisms that occur, so that the identity and rate of release of the pyrolysis products can be predicted, as a function of pressure and heating rate, based on the physical properties and molecular structure of the material. This information can then be used along with the gas-phase reaction models to correlate modifications of the nitramine ingredients with variations in die overall combustion. 

The estimation of properties from molecular structures is the task of deriving specific chemical, physical, and thermodynamic properties, for a chemical compound or a mixture of chemical compounds, under a specific set of conditions (usually temperature, pressure, and phase), based primarily on information about the molecular structures of the compounds involved (and the composition, in the case of a mixture). While many modem techniques (including molecular modeling, ab initio or semiempirical quantum-chemical computations of molecular orbitals, and density functional theory) involve substantial computational effort for any one system (molecule or simple mixture) they study, other methods involve direct correlations between property values and particular features of the molecular structures involved. The latter methods involve regression of a model with experimental data over a class of compounds these methods favor empirical approximations and arguments over fundamental models. 

An extensive series of studies for the prediction of aqueous solubility has been reported in the literature, as summarized by Lipinski et al. [15] and jorgensen and Duffy [16]. These methods can be categorized into three types 1 correlation of solubility with experimentally determined physicochemical properties such as melting point and molecular volume 2) estimation of solubility by group contribution methods and 3) correlation of solubility with descriptors derived from the molecular structure by computational methods. The third approach has been proven to be particularly successful for the prediction of solubility because it does not need experimental descriptors and can therefore be applied to collections of virtual compounds also. 

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