Eckhardt André K, Riu Martin-Louis Y, Müller Peter, Cummins Christopher C
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
J Am Chem Soc. 2021 Dec 22;143(50):21252-21257. doi: 10.1021/jacs.1c11426. Epub 2021 Dec 13.
Phosphoryl nitride (NPO) is a highly reactive intermediate, and its chemistry has only been explored under matrix isolation conditions so far. Here we report the synthesis of an anthracene () and phosphoryl azide based molecule (NP(O)) that acts as a molecular synthon of NPO. Experimentally, NP(O) dissociates thermally with a first-order kinetic half-life that is associated with an activation enthalpy of Δ = 27.5 ± 0.3 kcal mol and an activation entropy of Δ = 10.6 ± 0.3 cal mol K that are in good agreement with calculated DLPNO-CCSD(T)/cc-pVTZ//PBE0-D3(BJ)/cc-pVTZ energies. In solution NP(O) undergoes Staudinger reactivity with tricyclohexylphosphine (PCy) and subsequent complexation with tris(pentafluorophenyl)borane (B(CF), BCF) to form CyP-NP()O-B(CF). Anthracene is cleaved off photochemically to form the frustrated Lewis pair (FLP) stabilized NPO complex CyP-N═P-O-B(CF). An intrinsic bond orbital (IBO) analysis suggests that the adduct is zwitterionic, with a positive and negative charge localized on the complexing CyP and BCF, respectively.
磷酰氮化物（NPO）是一种高反应性中间体，到目前为止，其化学性质仅在基质隔离条件下进行过探索。在此，我们报告了一种基于蒽（）和磷酰叠氮化物的分子（NP(O)）的合成，该分子可作为NPO的分子合成子。实验表明，NP(O)以一级动力学半衰期进行热解离，其活化焓为Δ = 27.5 ± 0.3 kcal/mol，活化熵为Δ = 10.6 ± 0.3 cal/(mol·K)，这与计算得到的DLPNO - CCSD(T)/cc - pVTZ//PBE0 - D3(BJ)/cc - pVTZ能量高度吻合。在溶液中，NP(O)与三环己基膦（PCy）发生施陶丁格反应，随后与三（五氟苯基）硼烷（B(CF)，BCF）络合形成CyP - NP()O - B(CF)。蒽通过光化学作用被裂解，形成由受阻路易斯对（FLP）稳定的NPO络合物CyP - N═P - O - B(CF)。一种本征键轨道（IBO）分析表明，该加合物是两性离子型的，正电荷和负电荷分别定域在络合的CyP和BCF上。
