Mixed-base-stabilised chloroborylenes are easily accessed by twofold reduction of a cyclic (alkyl)(amino)carbene-supported trichloroborane in the presence of a second Lewis base, thus enabling fine-tuning of the electronic properties of the electron-rich borylene centre.

While a stable base-free arylalumylene bearing a sterically encumbered terphenyl substituent has been reported previously, we herein report that our attempts to form a base-stabilised arylalumylene bearing a relatively small...

We report the reduction of bulky ferrocenyl-based NHC-stabilised aluminium(III) diiodide [Fc*(NHC)AlI2] (Fc* = 2,5-bis(3,5-di-tert-butylphenyl)-1-ferrocenyl) in different hydrocarbon solvents (hexane, benzene, toluene, and p-xylene), which results in different outcomes. Reduction in...

Doubly N-heterocyclic-carbene-stabilized diborenes undergo facile reactions with CO 2 , initially providing dibora-βlactones. These lactones convert over time to their 2,4-diboraoxetan-3-one isomers through a presumed dissociative pathway and hypovalent boron species borylene carbonyls (LHBCO) and base-stabilized oxoboranes (LHBO). Repeating these reactions with doubly cyclic(alkyl)(amino)carbene-stabilized diborenes allowed the isolation of a borylene carbonyl intermediate, whereas a base-stabilized oxoborane could be inferred by the isolation of a boroxine from the reaction mixture. These results, supported by calculations, confirm the presumed mechanism of the diboralactone-to-diboraoxetanone isomerization while also establishing a surprising level of stability for three unknown or very rare hypovalent boron species: base-stabilized derivatives of the parent borylene carbonyl (LHBCO) and parent oxoborane (LHBO) as well as base-free oxoboranes (RBO).