Dolati Hadi, Denker Lars, Martínez Juan Pablo, Trzaskowski Bartosz, Frank René
Institute of Inorganic and Analytical Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.
Centre of New Technologies, University of Warsaw, Banacha 2 C, 02-097, Warszawa, Poland.
Chemistry. 2023 Nov 8;29(62):e202302494. doi: 10.1002/chem.202302494. Epub 2023 Sep 27.
While R C=N-R double bonds in organic imines are well established, the related iminoboranes R-B=N-R are either prone to oligomerization or can only be stabilized at sufficient steric congestion. In particular, the examples of unsubstituted parent B=N-H entity are rare. We demonstrate that the amino imidazoline-2-imine ligand system (HAmIm) not only gives rise to the isolation of a parent (AmIm)B=N-H iminoborane, but also to species of type (AmIm)B=N-SiMe with concomitant stabilization by lithium bromide. The double bond character in these systems is unambiguously corroborated by DFT calculations. The steric accessibility of the (AmIm)B=NH unit allows facile reactivity including metathesis reactions with C=O and C=S bonds, nucleophilic addition toward organic and organometallic carbonyl compounds, but also oxidative N-N coupling within a dimeric unit. Thus, the chemical behavior of the (AmIm)B=N-H and (AmIm)B=N-SiMe is distinctly different from that of organic imines.
虽然有机亚胺中的R C=N-R双键已得到充分证实，但相关的亚氨基硼烷R-B=N-R要么易于发生低聚反应，要么只能在足够的空间拥挤情况下才能稳定存在。特别是，未取代的母体B=N-H实体的例子很少。我们证明，氨基咪唑啉-2-亚胺配体体系（HAmIm）不仅能分离出母体（AmIm）B=N-H亚氨基硼烷，还能得到（AmIm）B=N-SiMe类型的物种，并通过溴化锂实现稳定化。这些体系中的双键特征通过密度泛函理论计算得到了明确证实。（AmIm）B=NH单元的空间可及性使得其具有包括与C=O和C=S键发生复分解反应、对有机和有机金属羰基化合物进行亲核加成以及在二聚单元内进行氧化N-N偶联等在内的容易发生的反应活性。因此，（AmIm）B=N-H和（AmIm）B=N-SiMe的化学行为与有机亚胺明显不同。
