Hydrophobicity Parameter of Diazines IV: A New Hydrogen‐Accepting Parameter of Monosubstituted (Di)azines for the Relationship of Partition Coefficients in Different Solvent Systems

Prediction of the 1-Octanol/H2O Partition Coefficient, Log P, by Ab Initio MO Calculations: Hydrogen-Bonding Effect of Organic Solutes on Log P

“…6 Yamagami et al recently proposed a new hydrogen-bonding accepting scale parameter, SHA, of a solute molecule in various dielectric environments by the semi-empirical MO with the COSMO 7,8 (conductor-like screening model) method. 9,10 They successfully analyzed the relationships between the observed log P and log PCL values of variously substituted diazines using the SHA parameter.…”

Application of a Stepwise Flow Ratiometry without Phase Separation to the Determination of the Chloroform/Water Distribution Coefficients of Volatile Diazines

“…Table 2 is the summary of the results obtained for the diazines. The log K D values determined by a shake flask method 9,11,15) are also listed, as reference. The log K D obtained from A S (ϭA o ϩA a ) were listed for less lipophilic compounds (log K D Ͻ1), because the addition of A o and A a is considered to give more reliable results.…”

“…Mono-and di-substituted diazines were selected as the compounds to be analyzed because their K D values in various solvents systems have been extensively explored in the studies of quantitative structure-activity relationships. [6][7][8][9][10][11] …”

Hydrogen-Bonding Abilities for Phenols Assessed by Quantitative Analyses of Their Partition Coefficients Derived from Different Partitioning Systems

“…1 as the general formula. 5,6,11) log P CL (log k)ϭa log P oct ϩrsϩs S HA ϩconst.(The rs (s: Hammett's type electronic substituent constant) and s S HA terms act as correction terms for hydrogenbonding effects; the rs term describes electronic effects of the substituent X on the change in hydrogen-bonding ability of the ring N-atom(s) and the s S HA term expresses the hydrogen-bonding ability of the X-substituent. The "a" value, the coefficient of the log P oct term, should be close to 1, provided the hydrophobic and hydrogen-bonding contributions are satisfactorily separated by Eq.…”

“…1,2) We have so far studied systematically log P oct values for heteroaromatic compounds and found it very important to estimate correctly the contribution of hydrogen-bonding effects involved in log P oct values for reliable prediction of log P oct . [3][4][5][6] Many efforts have been devoted to developing appropriate parameters to describe the hydrogen-bonding abilities. Among them, the indicator variable HB 7) and Abraham's hydrogen-bond acidity and basicity scales 8,9) are most frequently used.…”