Dolati Hadi, Denker Lars, 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 2C, 02-097, Warszawa, Poland.
Angew Chem Int Ed Engl. 2021 Feb 23;60(9):4633-4639. doi: 10.1002/anie.202015553. Epub 2021 Jan 12.
Boron reluctantly forms B=X (X=O, S, Se, Te) moieties, which has stimulated the quest for such species in the past few years. Based on the N,N'-chelating β-diketiminato ligand (HNacNac), a new amido imidazoline-2-imine ligand system (HAmIm) is presented, giving rise to the isolation of an exhaustive series of Lewis acid free, monomeric chalcogen B=X boranes with documented π-bond character between boron and the chalcogen. The chalcogenoboranes are isoelectronic and isolobal to the respective ketones. The chemical behavior of the oxoborane (B=O) strongly resembles the classical carbonyl reactivity in C=O bonds. The improved stability provided by HAmIm arises from the formation of more-stable five-membered boron chelates versus the six-membered NacNac analogues and from the imidazoline-2-imine moiety providing enhanced σ- and π-donation. The HAmIm ligand class may supersede the widely employed NacNac system in certain applications.
硼很难形成B=X（X = O、S、Se、Te）基团，这在过去几年激发了人们对这类物种的探索。基于N，N'-螯合β-二酮亚胺配体（HNacNac），提出了一种新的酰胺基咪唑啉-2-亚胺配体体系（HAmIm），从而分离出了一系列无路易斯酸的单体硫族元素B=X硼烷，这些硼烷在硼和硫族元素之间具有已记录的π键特征。硫族硼烷与相应的酮是等电子体且具有等瓣关系。氧硼烷（B=O）的化学行为与C=O键中的经典羰基反应性非常相似。HAmIm提供的稳定性提高源于与六元NacNac类似物相比形成了更稳定的五元硼螯合物，以及咪唑啉-2-亚胺部分提供了增强的σ-和π-给体作用。在某些应用中，HAmIm配体类别可能会取代广泛使用的NacNac体系。
