Structural Studies of Two Tinuvin® P Analogs: 2-(24-Dimethylphenyl)-2H-benzotriazole and 2-Phenyl-2H-benzotriazole

摘要

2-(2,4-Dimethylphenyl)-2H-benzotriazole (>1) has been synthesized in a three step procedure starting from 2,4-dimethyl-N-(2-nitrophenyl)benzamide via a 5-(2,4-dimethylphenyl)-1-(2-nitrophenyl)-1H-tetrazole intermediate. Its structure and those of Tinuvin^® P and 2-phenyl-2H-benzotriazole (>5) have been studied by multinuclear NMR (¹H-, ¹³C- and ¹⁵N-) in solution and in the solid state. X-ray diffraction analysis of >1 and >5 allowed to us establish the molecular conformation around the single bond connecting the two aromatic systems, in agreement with the conclusions drawn from the NMR study. In the case of >1 ab initio geometry optimization was achieved at the Hartree-Fock HF/6-31G** and DFT B3LYP/6-31G** levels.