Structural Studies of Two Tinuvin® P Analogs: 2-(2,4-Dimethyl-phenyl)-2H-benzotriazole and 2-Phenyl-2H-benzotriazole

• Main Authors: José Elguero, M. Rosario Torres, Elena Pinilla, Dolores Santa María, Rosa María Claramunt
• Format: Article
• Language: English
• Published: MDPI AG 2007-09-01
• Series: Molecules
• Subjects: 2-Arylbenzotriazoles; synthesis; NMR; X-ray analysis; DFT
• Online Access: http://www.mdpi.com/1420-3049/12/9/2201/
• ISSN: 1420-3049

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.