Correlation, property with molecular

The SPARC (Sparc Performs Automated Reasoning in Chemistry) approach was introduced in the 1990s by Karickhoff, Carreira, Hilal and their colleagues [16-18]. This method uses LSER [19] to estimate perturbed molecular orbitals [20] to describe quantum effects such as charge distribuhon and delocalizahon, and polarizability of molecules followed by quanhtative structure-activity relationship (QSAR) studies to correlate structure with molecular properties. SPARC describes Gibbs energy of a given process (e.g. solvation in water) as a sum of ... 

Correlation of Physical Chemical Properties with Molecular Size... 

Correlate bond order, bond strength (bond enthalpy), bond length, and magnetic properties with molecular orbital descriptions of molecules. (Section 9.8)... 

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. 

The measurement techniques most frequently used are derived from Raoult s and Van t Hoff s laws applied to cryometry, ebulliometry, osmometry, etc. They are not very accurate with errors on the order of ten per cent. Consequently, the molecular weight is often replaced by correlated properties. The mean average temperature or viscosity can thus replace molecular weight in methods derived from ndM. 

Chirality codes are used to represent molecular chirality by a fixed number of de-.scriptors. Thc.se descriptors can then be correlated with molecular properties by way of statistical methods or artificial neural networks, for example. The importance of using descriptors that take different values for opposite enantiomers resides in the fact that observable properties are often different for opposite enantiomers. 

Optical Properties. When light falls on an object, it is either partially absorbed, reflected, or transmitted. The behavior of the object as it relates to each of these three possibiUties determines visual appearance. Optical properties of fibers give useful information about the fiber stmcture refractive indexes correlate well with fiber crystalline and molecular orientation and birefringence gives a measure of the degree of anisotropy of the fiber. 

Molecular Connectivity Indexes and Graph Theory. Perhaps the chief obstacle to developing a general theory for quantification of physical properties is not so much in the understanding of the underlying physical laws, but rather the inabiUty to solve the requisite equations. The plethora of assumptions and simplifications in the statistical mechanics and group contribution sections of this article provide examples of this. Computational procedures are simplified when the number of parameters used to describe the saUent features of a problem is reduced. Because many properties of molecules correlate well with stmctures, parameters have been developed which grossly quantify molecular stmctural characteristics. These parameters, or coimectivity indexes, are usually based on the numbers and orientations of atoms and bonds in the molecule. 

The highly detailed results obtained for the neat ionic liquid [BMIM][PFg] clearly demonstrate the potential of this method for determination of molecular reorienta-tional dynamics in ionic liquids. Further studies should combine the results for the reorientational dynamics with viscosity data in order to compare experimental correlation times with correlation times calculated from hydrodynamic models (cf [14]). It should thus be possible to draw conclusions about the intermolecular structure and interactions in ionic liquids and about the molecular basis of specific properties of ionic liquids. 

The computational chemists were able to form collaborations with their fellow physical chemists. Some of the research questions dealt with molecular conformation and spectroscopy. The 1970s were full of small successes such as finding correlations between calculated and experimental properties. Some of these correlations were published. Even something so grand as the de novo design of a pharmaceutical was attempted but was somewhat beyond reach. 

Knowledge-based data mining algorithms used for correlation of molecular properties with specific activities play an increasingly significant role in modern strategies of chemical library design as relatively inexpensive, yet comprehensive tools. The ability to identify compounds with the desired... 

A property space can be defined using two classes of descriptors. The first class includes descriptors quantifying the variability (spread) of values their range is probably the most intuitive one. The second class of descriptors relates the dynamic behavior of a given property with other geometric or physicochemical properties. Such correlations can reveal if and how two molecular properties change in a coherent manner. 

Palm, K., Luthman, K., Ungell, A.-L., Strandlund, G., Artursson, P. Correlation of drug absorption with molecular surface properties./. Pharm. Sci. 1996, 85, 32-39. 

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