Force-induced retro-click reaction of triazoles competes with adjacent single-bond rupture. Issue 8 (13th June 2017)

• Record Type: Journal Article
• Authors: Stauch, Tim; Dreuw, Andreas
• Is Part Of: Chemical science. Volume 8:Issue 8(2017)
• Page Start: 5567
• Page End: 5575
• Publication Date: 2017-06-13
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7sc01562c
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Quantum chemical calculations reveal that mechanochemical cycloreversion of 1, 5-substituted triazoles competes with rupture of an adjacent single-bond. Abstract : The highly controversial force-induced cycloreversion of 1, 2, 3-triazole, its well-known retro-click reaction, is shown to be possible only for 1, 5-substituted triazoles, but competes with rupture of an adjacent single-bond. We draw this conclusion from both static and dynamic calculations under external mechanical forces applied to unsubstituted and 1, 4- and 1, 5-substituted triazoles. The JEDI (Judgement of Energy DIstribution) analysis, a quantum chemical tool quantifying the distribution of strain energy in mechanically deformed molecules, is employed to identify the key factors facilitating the force-induced retro-click reaction in these systems. For 1, 4-substituted triazoles it is shown to be impossible, but the parallel alignment of the scissile bond in 1, 5-substituted triazoles with the acting force makes it generally feasible. However, the weakness of the carbon–nitrogen bond connecting the triazole ring to the linker prevents selective cycloreversion.