General Treatment of Heteroatoms with the Randic Molecular Connectivity Index
Eugene J. Kupchik · Quantitative Structure-Activity Relationships · 1989
Abstract Excellent structure‐molar refraction relationships of alkylphosphines, dialkyl sulfides, alkylthiols, alkylamines, dialkyl ethers, and aliphatic alcohols were obtained using the Randic molecular connectivity index. Excellent structure‐molar refraction relations were also obtained using two empirically‐modified connectivity indices which reflect either the difference in bond length between the heteroatom‐carbon bond and a carbon‐carbon bond or the difference in covalent radius between the heteroatom and a carbon atom. Use of the empirically‐modified indices improves the prediction of molar refraction for a mixed set of alkylphosphines, dialkyl sulfides, alkylthiols, alkylamines, dialkyl ethers, aliphatic alcohols, alkanes, alkylsilanes, alkylgermanes, and alkyl halides.