Experimental and theoretical investigation on the thermal isomerization reaction of tristriazolotriazines. (30th March 2022)

• Record Type: Journal Article
• Authors: Jochem, Matthias; Limbach, Daniel; Glang, Stefan; Haspel, Tobias; Detert, Heiner
• Is Part Of: Journal of physical organic chemistry. Volume 35:Number 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-30
• Subjects: discotic liquid crystal -- DFT calculation -- heterocycles -- kinetics -- mesomorphism -- rearrangement; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.4346
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: The isomerization of tristriazolotriazione with tangential substituents to radial isomers occurs in a cascade of three ring opening/rotation/ring closure steps of the central triazine. Donor substitution accelerates the isomerization which can be catalyzed by Brønsted acids. The velocity of the rearrangements drops with each step by a factor of 4, whereas the gain in heat of formation increases. Density functional theory (DFT) calculations led to transition states; their energies correspond to the experimental data. Threefold isomerization strongly affects the mesomorphic properties. Abstract : The isomerization of tristriazolotriazione with tangential substituents to radial isomers occurs in a cascade of three ring opening/rotation/ring closure steps of the central triazine. Donor substitution accelerates the isomerization which can be catalyzed by Brønsted acids. The velocity of the rearrangements drops with each step by a factor of 4, whereas the gain in heat of formation increases. Density functional theory (DFT) calculations led to transition states; their energies correspond to the experimental data.