Thermal isomerization of acetylnitrene: a quantum-chemical study

Infrared spectrum and UV-induced photochemistry of matrix-isolated 5-methoxy-1-phenyl-1H-tetrazole

“…The primarily formed phenylazide partially converted to ACHT, with all probability involving singlet phenylnitrene as intermediate. The identification of all the photoproducts as well as the interpretation of the spectrum of the isolated 5MPT were supported by extensive DFT calculations and, whenever available, by previously reported data on these compounds as matrix-isolated species or in the gaseous phase [15,19,[52][53][54].…”

“…3 and Table 2). Methylcyanate is a quite unstable compound under normal experimental conditions and in particular in solid phase, isomerizing quickly to its more stable isomer methylisocyanate [50][51][52][53] (the DFT(B3LYP)/6-311++G(d,p) calculated energy of methylisocyanate is 127.5 kJ mol −1 lower than that of methylcyanate). Its synthesis was first reported in 1965, by two different groups [50,51], although a pure sample could not be obtained for spectroscopic investigation because of the instability of the molecule.…”

Assessing the effective factors affecting the conformational preferences and the early and late transition states of the unimolecular retro-ene decomposition reactions of ethyl cyanate, ethyl thiocyanate and ethyl selenocyanate

“…Also, they mentioned that the anti-conformation of ethyl cyanate is more stable than its gauche-conformation by about 0.16 kcal mol À1 (as calculated at the CCSD(T)/6-311+G(2d,2p)//B3LYP/6-311+G(2d,2p) level of theory), which is similar to the result obtained by Leszczynski and co-workers. 19 It is worth noting that Pasinszki and co-workers 20 mentioned that the conversion of ethyl thiocyanate to its isothiocyanate isomer in the gas phase could not be take place via a unimolecular process at ambient temperature [B3LYP/6-311+G(2d,2p): DG s (ethyl cyanate/ethyl isocyanate) ¼ 52.31 kcal mol À1 ], which is in the line with the results obtained by Faustov and co-workers 21 for methyl cyanate [G2(MP2, SVP): DG s (methyl cyanate/methyl isocyanate) ¼ 62.6 kcal mol À1 ].…”

Experimentelle und theoretische Untersuchungen der Synthesen, spektroskopischen Daten und Reaktionen des Formylazids

“…Möglicherweise sind zwei Gründe dafür verantwortlich, dass Experimentatoren bei der Erzeugung von 3 a Zurückhaltung zeigten: Quantenchemische Rechnungen sagen für die Aktivierungsenergie des Prozesses 3 a → 4 a signifikant kleinere Werte voraus als für die Curtius‐Umlagerung von Acetyl‐ oder Benzoylazid (Differenzen von 3.4–4.9 bzw. 6.5–10.5 kcal mol −1 ) 3e–j. Folglich sollte 3 a bereits deutlich unterhalb Raumtemperatur sehr instabil sein.…”