Abstract: On the basis of AM1 method, the interactions between the squaraines and the anions, such as F^-, Cl^-, Br^-, O^2-, S^2-, etc., have been studied by means of the proposed modeLIN which the anion approaches vertically the center of the four-membered rings of the squaraine. The calculated results suggest that the squaraines are characterized by the particular electron-defect rings and tend to act upon the electron-rich anions. The strength of these action is related to the charges and polarizabilities of the anions and is improved by the introduction of electron with drawing groups.

Key words: Squaraines, Electrophilic activities, AM1 method