HOMO-LUMO, IRFRARED FREQUENCIES AND MOLECULAR GEOMETRY COMPARSION STUDY OF THE STRENGTH OF BORON TRIHALIDES ACIDITY USING AM1 MOLECULAR MODELING

Abstract

AM1 Molecular Modeling has been used in the comparison of Lewis acid strength of Boron Trihalide using available opportunities in this method such as HOMO-LUMO gap , infrared frequencies and molecular geometry. HOMO-LUMO separation was employed to evaluate acid strength of BX3, and results show that BI3 is more acidic than others and acidity has decreased up to halogen group. When complex formation between BX3 and dimethylamine was made , N—H bond stretching alters to red shift ( lower frequency) .It was found that I3BNH(CH3)2 has the lowest frequency for this bond .Geometry for these complexes , B—N bond length and degree of X-B-X angle of all mentioned complexes were also studied and pyramidal structure for complexed BX3 were observed.