具有 N,N'-二芳基喹唑啉-4-酮主链的稳定 N-杂环卡宾：改进的合成、电子性能和反应性,Organometallics

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具有 N,N'-二芳基喹唑啉-4-酮主链的稳定 N-杂环卡宾：改进的合成、电子性能和反应性
Organometallics ( IF 2.5 ) Pub Date : 2024-01-09 , DOI: 10.1021/acs.organomet.3c00466
J. Maurice Pütz ₁ , Simone T. Hauer ₂ , Joscha Nellesen ₁ , Daniel Deißenbeck ₃ , Thomas J. J. Müller ₂ , Jan Meisner ₃ , Christian Ganter ₁

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我们提出了一种制备阳离子N , N '-二芳基取代的喹唑啉-4-酮衍生物的新途径，该衍生物可作为合成新N , N '-二芳基-氨基-酰胺卡宾5a,b的前体，该卡宾在惰性下稳定状况。四氟类似物5c可以耐受隔离，但可以原位制备和使用。根据耦合常数¹J _C,H (210–214 Hz) 和⁷⁷ Se NMR 共振 (545–654)所表明的 NMR 和 IR 光谱研究，新的 NHC 表现出强大的 σ 供体能力以及强大的 π 接受特性。 ppm) 合适的衍生物。^{值得注意的是，如 TEP 值从 2053 cm –1} ( 5a ) 到 2055 cm的小幅变化所示，用氟原子取代稠合苯环的氢原子对卡宾的整体供体性质仅产生很小的影响^–1（5c）。NHC 5的两亲反应性通过它们与异腈的反应得到支持，以提供各自的烯酮亚胺13，其显示出由水或热诱导的前所未有的重排反应。NHC 5还可以与胺或甲醇发生 N-H 和 O-H 键活化反应。通过量子化学计算研究了这些活化反应的机制。由于所选衍生物具有明显的蓝色发射，因此在溶液和固态中对光物理性质进行了示例性表征，并通过 (TD)-DFT 计算将其分配给基础电子跃迁。

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Stable N-Heterocyclic Carbenes with the N,N′-Diarylquinazolin-4-one Backbone: Improved Synthesis, Electronic Properties, and Reactivity

We present a new pathway toward cationic N,N′-diaryl-substituted quinazolin-4-one derivatives, which act as precursors for the synthesis of new N,N′-diaryl-amino-amido carbenes 5a,b that are stable under inert conditions. A tetrafluoro analogue 5c withstands isolation but can be prepared and employed in situ. The new NHCs exhibit a strong σ-donor capacity as well as strong π-accepting properties according to NMR and IR spectroscopic investigations indicated by the coupling constants ¹J_C,H (210–214 Hz) and ⁷⁷Se NMR resonances (545–654 ppm) of suitable derivatives. Remarkably, replacement of the hydrogen atoms of the anellated benzene ring by fluorine atoms exerts only a small effect on the overall donor properties of the carbene, as suggested by a small shift of the TEP values from 2053 cm^–1 (5a) to 2055 cm^–1 (5c). An ambiphilic reactivity of the NHCs 5 is supported by their reactions with isonitriles to provide the respective ketenimines 13, which show unprecedented rearrangement reactions, induced by either water or heat. The NHCs 5 also react with amines or methanol in N–H and O–H bond activations. The mechanisms of these activation reactions were investigated by quantum chemical calculations. Due to the apparent blue emission of the selected derivatives, the photophysical properties were exemplarily characterized in solution and solid state and assigned to the underlying electronic transitions by (TD)-DFT calculations.

更新日期：2024-01-09

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