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Kiralj R., Ferreira M. M. C., “Predicting Bond Lengths in Planar Benzenoid Polycyclic Aromatic Hydrocarbons: A Chemometrics Approach”. J. Chem. Inf. Comput. Sci., 42(3), 508-523 (May-Jun 2002).
[Article in section: Chemical Computation. Cited in the WebCite database at the Cambridge Crystallographic Data Centre: http://www.ccdc.cam.ac.uk/free_services/webcite/. See Notes, Notes2 and Notes3.]

Abstract.
Two hundred and twenty-three aromatic carbon-carbon bond lengths in high precision crystal structures containing 22 planar
condensed benzenoid polycyclic aromatic hydrocarbons (PB-PAHs) were related to the Pauling p-bond order. its analogue
corrected to crystal packing effects, the number of hexagonal rings around the bond. and the numbers of carbons atoms around
the bond at topological distance one and two. Principal Component Analysis (PCA) showed that the bond lengths in
PB-PAHs are at least two-dimensional phenomenon, with well pronounced classification into 12 types of bonds, as confirmed
with Hierachical Cluster Analysis (HCA). Consequently, Multiple Linear Regression (MLR) and Partial Least Squares (PLS)
models were superior to univariate models, reducing the degeneration of the data set and improving the estimation of Julg's
structural aromaticity index. The approximate regression models based on topological descriptors only were built for fast and
easy prediction of bond lengths and bond orders in PB-PAHs.

Keywords.

Keywords Plus.
Crystal structures; Valence Bond; Orders; Systems.