Facile Energy Release from Substituted Dewar Isomers of 1,2‐Dihydro‐1,2‐Azaborinines Catalyzed by Coinage Metal Lewis Acids

• Published in: Angewandte Chemie 2024-07, Vol.136 (30), p.n/a
• Main Authors: Richter, Robert C., Biebl, Sonja M., Einholz, Ralf, Walz, Johannes, Maichle‐Mössmer, Cäcilia, Ströbele, Markus, Bettinger, Holger F., Fleischer, Ivana
• Format: Article
• Language: English
• Subjects: Azaborinine; Catalysts; Crystal structure; Dewar isomer; Energy storage; Internal energy; Isomers; Lewis acid; Lewis acids; Low temperature; Magnetic resonance spectroscopy; NMR spectroscopy; photoisomerization; Silver; Solar energy; Solar heating
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202405818

Molecular solar thermal systems (MOST) represent an auspicious solution for the storage of solar energy. We report silver salts as a unique class of catalysts, capable of releasing the stored energy from the promising 1,2‐dihydro‐1,2‐azaborinine based MOST system. Mechanistic investigations provided insights into the silver catalyzed thermal backreaction, concurrently unveiling the first crystal structure of a 2‐aza‐3‐borabicyclo[2.2.0]hex‐5‐ene, the Dewar isomer of 1,2‐dihydro‐1,2‐azaborinine. Quantification of activation energies by kinetic experiments has elucidated the advantageous energy change associated with Lewis acid catalysts, a phenomenon corroborated through computational analysis. By means of low temperature NMR spectroscopy, mechanistic insights into the coordination of Ag+ to the 1,2‐dihydro‐1,2‐azaborinine were gained. Molecular solar thermal (MOST) systems offer a promising solution for solar energy storage. We present silver salts as a distinctive catalyst class capable of releasing stored energy from the promising dihydroazaborinine‐based MOST system. Through mechanistic investigations and computational analysis, we gained insights into the silver‐catalyzed thermal back reaction, while revealing the first crystal structure of a Dewar dihydroazaborinine.