Structural and conformational analysis of 1,2-bis(benzotriazol-1-yl)ethane

The compound 1,2-bis(benzotriazol-1-yl)ethane (BBTA) was prepared and its structure was determined by X-ray analysis. The compound crystallizes in monoclinic space group P21/c with aZ7.526(2) A° , bZ10.836(2) A° , cZ8.412(2) A° , bZ116.629(5)8, VZ613.2(3) A° 3, ZZ2, and DZ1.431 Mg/m3. The structure was solved by direct methods and refined to RZ0.0537 and wR2Z0.1302 by full matrix anisotropic least-squares methods. The molecular geometry of the anti-BBTA in the ground state has been calculated using the restricted Hartree–Fock and density functional method (B3LYP) with 6-31G* basis set. The optimized geometric bond lengths and bond angles obtained by using B3LYP/6-31G* are better agreement with the experimental values than those by using RHF/6-31G*. The conformers located at minima by RHF/STO-3G calculation were re-optimized by using B3LYP/6-31G* method. Two anti conformations (A(1) and A(2)) and two gauche conformations (G(1) and G(2)) were obtained. The B3LYP/6-31G* relative energies for A(1), A(2), G(1) and G(2) conformers are 0.00, 1.09, 1.52 and 2.07 kcal/mol, respectively. In addition, a qualitative estimation of the chemical behaviors of the stable conformers has been investigated by analyzing charges of the nitrogen atoms in the benzotriazole ring. q 2004 Elsevier B.V. All rights reserved.