BINDING-ENERGIES OF SOME ALUMINUM-CHLORIDE COMPLEXES OF POLY(P-PHENYLENEBENZOBISTHIAZOLE) (PBZT) MODEL COMPOUNDS

Ab initio molecular orbital calculations on aluminum chloride complexes of benzothiazole show that aluminum chloride binds more tightly to the nitrogen atom (D(e) = 36.5 kcal) than to the sulfur atom (D(e) = 10.2 kcal) and it is energetically more feasible for Al2Cl6 to complex at the nitrogen atom than for AlCl3 to complex simultaneously at the nitrogen and at the sulfur. These results have relevance regarding the structure proposed for PBZT dissolved in Lewis acid containing aprotic solvents. New calculational results are also reported for AlC13-NH3 (D(e) = 42.1 kcal), AlCl3-H2S (D(e) = 13.7 kcal), and Al2Cl6-NH3 (D(e) = 30.6 kcal for dissociation to NH3, D(e) = 7.2 kcal for dissociation to AlCl3-NH3 and AlCl3).