Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706-1322, USA.
J Org Chem. 2010 Mar 19;75(6):1815-21. doi: 10.1021/jo9026462.
Stimulated and intrigued by the report of the synthesis of diazirinone (1), a metastable adduct of N(2) and CO, we carried out further experimental and theoretical studies aimed at the detailed spectroscopic characterization of this species. Our attempts to generate and detect diazirinone (1) in either the condensed phase (using matrix isolation spectroscopy) or in the gas phase (using millimeter-wave rotational spectroscopy), however, have been unsuccessful. Trapping the volatile products produced from the reaction of 3-chloro-3-(p-nitrophenoxy)diazirine (5) with tetrabutylammonium fluoride (TBAF) under matrix-isolation conditions affords chlorofluorodiazirine (8) and carbon monoxide but fails to provide evidence for diazirinone (1). Moreover, sophisticated ab initio calculations of the structure and fundamental vibrational frequencies of diazirinone (1) produce an estimate for the fundamental band origin of the C=O stretch (2046 cm(-1)) that is ca. 100 cm(-1) lower in frequency than the experimental value previously attributed to this band. This discrepancy lies well outside any expected solvent shift or calculation error at this level of theory. In an effort to reconcile our findings with the earlier reports concerning diazirinone (1), we reconsidered the infrared spectral evidence upon which the original claim of diazirinone synthesis was based. New experiments demonstrate that these spectra may be explained and reproduced with a combination of solution-phase and gas-phase absorptions of CO, without recourse to invoke diazirinone (1).
受合成二氮烯酮（1）的报告的启发和吸引，1 是 N(2)和 CO 的亚稳加合物，我们进行了进一步的实验和理论研究，旨在对该物种进行详细的光谱特征描述。然而，我们试图在凝聚相（使用基质隔离光谱学）或气相（使用毫米波旋转光谱学）中生成和检测二氮烯酮（1）的尝试均未成功。在基质隔离条件下，用四丁基氟化铵（TBAF）捕获 3-氯-3-（对硝基苯氧基）二氮烯（5）反应产生的挥发性产物得到氯氟二氮烯（8）和一氧化碳，但未能提供二氮烯酮（1）的证据。此外，对二氮烯酮（1）的结构和基本振动频率进行的复杂从头算计算得出 C=O 伸缩的基本带原点估计值（2046 cm(-1))，比以前归因于该带的实验值低约 100 cm(-1)。这种差异远远超出了该理论水平的任何预期溶剂位移或计算误差。为了使我们的发现与先前关于二氮烯酮（1）的报告相一致，我们重新考虑了原始合成二氮烯酮（1）报告所依据的红外光谱证据。新的实验表明，这些光谱可以通过 CO 的溶液相和气相吸收的组合来解释和重现，而无需援引二氮烯酮（1）。
