Structural stability and analysis of vibrational spectra of 1,2,4,5-tetroxane and 3,6-diphenyl-1,2,4,5-tetroxane

✍ Scribed by H.M. Badawi; A.A. Al-Saadi; S.A. Ali

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 319 KB
• Volume: 969
• Category: Article
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2010.02.015

✦ Synopsis

The diperoxide 3,6-diphenyl-1,2,4,5-tetroxane was synthesized and its infrared and Raman spectra were measured. The structural stability and the vibrational spectra of 1,2,4,5-tetroxane and 3,6-diphenyl-1,2,4,5-tetroxane were investigated by the DFT-B3LYP and the ab initio MP2 calculations with the 6-311G ** basis set. From the calculations, the chair form of 1,2,4,5-tetroxane was predicted to be about 9, 20, and 50 kcal/mol lower in energy than the twist, boat, and planar structures, respectively. The ring inversion in 1,2,4,5-tetroxane is concluded to take place most probably through the twist structure of the ring. In the case of 3,6-diphenyl-1,2,4,5-tetroxane, the planar-equatorial (P eq ) conformation was predicted by both levels of theory to be the lowest energy and predominant form of the molecule. The planar perpendicular and axial equatorial interconversion barriers were calculated to be about 2 and 12 kcal/mol, respectively. Reliable vibrational assignments were provided for the spectra of 1,2,4,5-tetroxane and 3,6-diphenyl-1,2,4,5-tetroxane by combining experimental and theoretical data of the two molecules.