Distance Indices and Their Hyper-Counterparts: Intercorrelation and Use in the Structure-Property Modeling

• Published in: SAR and QSAR in environmental research Vol. 12; no. 1-2; pp. 31 - 54
• Main Authors: Trinajstič, N., Nikolič, S., Basak, S. C., Lukovits, I.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 2001
• Subjects: Alkanes - chemistry; Carbon - chemistry; Chemical Phenomena; Chemistry, Physical; Distance indices; Hyper-distance indices; Intercorrelation; Models, Theoretical; Saturated hydrocarbons; Structure-Activity Relationship; Structure-boiling point modeling; Temperature
• ISSN: 1062-936X; 1029-046X
• DOI: 10.1080/10629360108035370

Intercorrelation between the Wiener index, hyper-Wiener index, Harary index, hyper-Harary index, detour index and hyper-detour index is studied on three sets of branched and unbranched alkanes and cycloalkanes with up to eight carbon atoms. First set (S-39) contains all alkanes from ethane to octane (39 molecules), the second set (S-139) 139 cyclic hydrocarbons from cyclopropane to branched and unbranched polycyclic octanes and the third set (S-178) is a combination of the first two sets (178 molecules). It is found that the pairs of distance indices and the corresponding hyper-counterparts are highly intercorrelated for all three sets. The use of the distance indices of both kinds in structure-boiling point modeling was analyzed. Distance indices and hyper-distance indices do not lead to particularly good models for any of the three sets. When used as composite indices they give much-improved models. However, they are most useful when combined with such indices as the number of carbon atoms in a hydrocarbon, Hosoya Z index and/or total walk count index. The following standard errors of estimate are obtained for the best models based on the combination of descriptors: 2.1°C (S-39), 4.4°C (S-139) and 4.1°C (S-178). They compare favorably with the related models in the literature.