Describing hydrogen-bond acidity with quantum chemical parameters

The correlations between the overall hydrogen-bond acidities Sigma alpha (H )(2) of 137 diverse compounds and their quantum;chemical parameters have be en studied. For the compounds having hydroxyl or carboxyl, Sigma alpha (H)( 2) = -0.027 7+3.826Q(H)-0.027 3E(LUMO)-0.065 4E(HOMO)+3.085Q(o)(n=70, r=0. 982). The quantum chemical parameters Q(H), E-LUMO, E-HOMO and Q(O) are the net charge of the hydrogen atom in the hydroxyl or carboxyl of the compoun ds, the energy of the lowest est unoccupied molecular orbital, the energy o f the highest occupied molecular orbital and the net charge of the oxygen b inding with the hydrogen atom in the hydroxyl or carboxyl, respectively. Fo r the compounds having amino group, Sigma alpha (H)(2) = -1.569+3.637Q(H)- 0.123 5E(HOMO) (n=49, r=0.985). Q(H) is the net charge of the hydrogen atom having greater positive net charge in the amino group. For the compounds h aving imino group, Sigma alpha (H)(2) -0.472+3.676Q(H)(n=18, r= 0.993). Q(H ) is the net charge of the hydrogen atom in the imino group.