Engineering the Frontier Orbitals of a Diazadiborinine for Facile Activation of H2 , NH3 , and an Isonitrile.

An annulated 1,3,2,5-diazadiborinine with 14 π electrons has been synthesized and fully characterized. Experimental and computational studies revealed that this compound features a rather small HOMO-LUMO gap, which leads to enhanced reactivity towards small molecules. Thus, the 1,3,2,5-diazadiborinine readily cleaves the H-H bond of dihydrogen and an N-H bond of ammonia under mild conditions. Moreover, it reacts with 2,6-dimethylphenylisonitrile in a [4+1] cycloaddition at room temperature.