Partition atom-based calculation

Pearlman [24] has developed a partitioning method based on the BCUT values described earlier. Different methods are available for calculating the atomic... 

Koritsanszky, T. S. Coppens, P. Chemical applications of X-ray charge-density analysis, Chem. Revs. 2001, 101, 1583-1627 Volkov, A. Coppens, P. Calculation of electrostatic interaction energies in molecular dimers from atomic multipole moments obtained by different methods of electron density partitioning, J. Comp. Chem. 2004, 25, 921-934 Suponitsky, K. Y Tsirelson, V. G. Fell, D. Electron-density-based calculations of intermolecular energy the case of urea, Acta Cryst. 1999, A55, 821-827. 

Table 1 Calculation of some molecular-based descriptors for BOA, DIMBOA and MBOA. Physicochemical descriptor like logP (partition coefficient between octanol and water) constitutional descriptors like the number of a specified atoms or bonds (number of carbons, hydrogens, oxygens, nitrogens, single and aromatic bonds, the total number of atoms and bonds) and molecular weight quantum-mechanical descriptors like HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital).

Molecular connectivity indices are desirable as potential explanatory variables because they can be calculated for a nominal cost (fractions of a second by computer) and they describe fundamental relationships about chemical structure. That Is, they describe how non-hydrogen atoms of a molecule are "connected". Here we are most concerned with the statistical properties of molecular connectivity Indices for a large set of chemicals In TSCA and the presentation of the results of multivariate analyses using these Indices as explanatory variables to understand several properties important to environmental chemists. We will focus on two properties for which we have a relatively large data base (1) biodegradation as measured by the percentage of theoretical 5-day biochemical oxygen demand (B0D)( 11), and (2) n-octanol/water partition coefficient or hereafter termed log P (12). 

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