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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. May 2003, Volume 2, Number 5, 288-305 |
Comparative QSPR Studies with Molecular Connectivity, Molecular
Negentropy and TAU Indices. Part 2. Lipid-Water Partition Coefficient
of Diverse Functional Acyclic Compounds
Kunal Roy and Achintya Saha
Internet Electron. J. Mol. Des. 2003, 2, 288-305
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Abstract:
In late eighties, topochemically arrived unique (TAU)
scheme was described by Pal et al. in valence electron mobile
(VEM) environment and this index was claimed to have
power to decode chemical information in somewhat better
way than molecular connectivity index (MCI). The TAU
scheme is unique in that it unravels specific contributions of
functionality, branching, shape and size factors to the
physicochemical property or biological activity while other
indices give mainly a global contribution of the molecule.
Subsequently, several papers described QSAR and QSPR
with TAU index to show the diagnostic potential of the
parameter, but much work has not been done on the index.
Thus, a comparison among the relations involving these
indices may explore relative suitability of the schemes in
describing physicochemical parameters. The present
communication attempts to correlate lipid-water partition
coefficient (log P) of 168 diverse functional acyclic
compounds with TAU indices and to compare those with
relations involving molecular negentropy (I) and first order
valence molecular connectivity (1χv) indices to
explore the diagnostic feature of TAU scheme. This study shows that
TAU indices can unravel specific contributions of molecular
bulk (size), functionality, branching and shape parameters to
the lipophilicity of diverse functional compounds. In general,
lipophilicity increases with increase in molecular bulk and
skeletal index value, and decreases with increase in
branching and functionality. The TAU index is an important
tool in exploring structure-property relationship studies in
view of its potential to unravel specific contribution of
different structural parameters like molecular bulk, shape
factors, branching, functionality and carbon skeletal
structure.
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