N-Methylcarbamoyl azide: spectroscopy, X-ray structure and decomposition via methylcarbamoyl nitrene

Wan, Huabin; Li, Hongmin; Xu, Jian; Wu, Zhuang; Liu, Qifan; Chu, Xianxu; Abe, Manabu; Bégué, Didier; Zeng, Xiaoqing

doi:10.1039/c7qo00277g

Cited by 11 publications

(14 citation statements)

References 42 publications

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“…The two interacting azide molecules reside in different parallel planes with a distance of 1.3 Å (Figure B). Similar intermolecular hydrogen bonds (N–H ··· O=C) with D–H ··· A lengths of 2.85 Å and angles of 147.7° have also been found in solid carbamoyl azide Me(H)NC(O)N 3 …”

Section: Resultssupporting

confidence: 63%

“…Whereas, the two pyrroyl nitrenes 2 and 6 in the CSS state adopt the partial oxazirine structures, as evidenced by the much smaller O–C–N angles (92°) in the CSS state than those in the OSS (117°) and T (118°) states. The O–C–N angles (92°) in the CSS state of pyrroyl nitrenes 2 and 6 are slightly larger than those in the CSS of carbamoylnitrene Me(H)NC(O)N [ syn : 90.6°; anti : 90.9°, CASPT2(8,8)/6‐311+G**] …”

Section: Resultsmentioning

confidence: 99%

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Photodecomposition of 1H‐Pyrrole Carbonyl Azides: Direct Observation of Singlet 1H‐Pyrrole Carbonyl Nitrenes and Triplet 1H‐3‐Pyrrylnitrene

Liu

Wan

et al. 2018

Eur J Org Chem

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The two simplest pyrroylazides, namely 1H‐pyrrole‐2‐carbonyl azide (1) and 1H‐pyrrole‐3‐carbonyl azide (5), have been fully characterized by vibrational spectroscopy (IR and Raman) and X‐ray crystallography. The photo‐induced stepwise decomposition of both azides has been studied by combining matrix‐isolation IR spectroscopy (N2 matrix at 15 K) and quantum chemical calculations. Upon laser irradiation at 266 nm, both pyrroylazides split off molecular nitrogen and yield the corresponding pyrroylnitrenes (2 and 6) in the closed‐shell singlet state. Subsequent irradiation of 2 with UV‐light (365 nm) results in Curtius rearrangement to 2‐pyrrylisocyanate (3), as followed by laser‐induced (266 nm) CO‐elimination and the formation of ring‐opening product imines (9) in Z and E‐conformations. Similar rearrangement of 6 to 7 occurs under the green‐light (532 nm) irradiation, and the latter eliminates CO and furnishes the elusive 1H‐3‐pyrrole nitrene (8) in the triplet state. The first‐time spectroscopic identification of pyrroylnitrenes (2 and 6) and 3‐pyrrylnitrene (8) has been supported by 15N‐labeling experiments and quantum chemical calculations.

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Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Photodecomposition of 1H‐Pyrrole Carbonyl Azides: Direct Observation of Singlet 1H‐Pyrrole Carbonyl Nitrenes and Triplet 1H‐3‐Pyrrylnitrene

Liu

Wan

et al. 2018

Eur J Org Chem

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“…Electron‐withdrawing substituents stabilize the triplet nitrenes and result in triplet ground states for phosphoryl‐ and sulfonylnitrenes with D values on the order of 1.6 cm −1 (Table S1). These nitrenes largely fit the D‐ρ correlation, but alkoxycarbonylnitrenes and carbamoylnitrenes have D values 12–14 % higher than expected from the spin densities (Figure and Table S1). This suggests the presence of SOC, and in fact our ORCA calculations indicate a SOC contribution of about 10 % to the value of D , which brings D into agreement with experiment and explains the significant E values.…”

Section: Triplet Nitrenes and Carbenes Spin Densities And Mixing Ofmentioning

confidence: 90%

“…(15)], [62] and carbamoylnitrenes R 2 NÀCOÀN [Eq. (16)] [63] have been prepared by either FVP or matrix photolysis of azide or isocyanate precursors and characterized by IR and/or ESR spectroscopy.…”

Section: Triplet and Singlet Acylnitrenes (Oxazirines)mentioning

confidence: 99%

Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry

Wentrup

2018

Angew Chem Int Ed

115

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Carbenes and nitrenes can exist in both singlet and triplet states, sometimes equally stable and interconverting either thermally or photochemically. Many carbene and nitrene reactions proceed via tunneling at low temperatures. Numerous singlet and triplet states have been characterized spectroscopically, and a detailed understanding of the chemical and physical properties of carbenes and nitrenes is emerging. There has been significant progress in the direct observation of carbenes, nitrenes, and many other reactive intermediates in recent years through the application of matrix photolysis and flash vacuum pyrolysis linked with matrix isolation at cryogenic temperatures. Our understanding of singlet and triplet states has improved through the interplay of spectroscopy and computations. Bistable carbenes and nitrenes as well as many examples of tunneling have been discovered and numerous rearrangements and fragmentations have been documented. The correlation of the zero-field splitting parameter D with calculated spin densities on nitrenes and carbenes is discussed. This Minireview gives an overview of some of these developments.

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“…[8][9][10][11][12] Subsequently, Zeng et al published the structures of N-methylcarbamoyl azide, as well as of aryl substituted carbonyl azides such as 1H-pyrrole carbonyl azide. [13,14] Recently, Benz et al successfully synthesized and characterized nitrocarbamoyl azide, which shows remarkable stability. [15] The publication by Benz mentioned the existence of two carbonyl azides, namely, oxalyl diazide and carbamoyl azide, however, neither were characterized (Figure 1).…”

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confidence: 99%

Synthesis, Characterization and Energetic Performance of Oxalyl Diazide, Carbamoyl Azide, and N,N’‐Bis(azidocarbonyl)hydrazine

et al. 2021

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As pure compounds, small carbonyl azides enjoy a bad reputation, due to the high explosive sensitivity and instability they demonstrate. Consequently, most reported examples have only been poorly characterized. The compounds oxalyl diazide (1), carbamoyl azide (2), as well as N,N’‐bis(azidocarbonyl)hydrazine (3) were obtained by performing a diazotation reaction on the corresponding hydrazo precursor. Carbamoyl azide (2) could also be obtained from oxalyl diazide via Curtius rearrangement to the reactive isocyanate, followed by reaction with water. Further, different trapping reactions of the isocyanate with hydroxyl (methanol, oxetan‐3‐ol) and amino (2‐amino‐5H‐tetrazole) functions are described. All products were extensively analyzed using IR, EA, DTA and multinuclear NMR spectroscopy, and the crystal structures elucidated using single crystal X‐ray diffraction. In addition, the sensitivities toward friction and impact were determined and the energetic performances of the carbonyl azides were calculated using the EXPLO5 code.

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N-Methylcarbamoyl azide: spectroscopy, X-ray structure and decomposition via methylcarbamoyl nitrene

Abstract: N-Methylcarbamoyl azide has been characterized and the nitrene intermediate in its Curtius-rearrangement has been observed in two conformations by matrix-isolation IR and EPR spectroscopy.

Cited by 11 publications

References 42 publications

Photodecomposition of 1H‐Pyrrole Carbonyl Azides: Direct Observation of Singlet 1H‐Pyrrole Carbonyl Nitrenes and Triplet 1H‐3‐Pyrrylnitrene

Photodecomposition of 1H‐Pyrrole Carbonyl Azides: Direct Observation of Singlet 1H‐Pyrrole Carbonyl Nitrenes and Triplet 1H‐3‐Pyrrylnitrene

Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry

Synthesis, Characterization and Energetic Performance of Oxalyl Diazide, Carbamoyl Azide, and N,N’‐Bis(azidocarbonyl)hydrazine

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