Small Cationic Boron and Boron‐Nitrogen Rings, Synthesized from Diboranes with Charge‐Delocalizing Guanidinate Substituents

We report the straightforward synthesis and characterization of small polycationic boron and boron‐nitrogen rings, stabilized by charge‐delocalizing guanidinate substituents. Reaction between a ditriflato‐diborane with two electron‐donating bridging bicyclic guanidinate substituents and the corresponding dihydrido‐diborane leads to a dicationic B 4 ring with a 4c,4e‐bond in the planar rhomboid B 4 skeleton. Reaction of the same ditriflato‐diborane with the corresponding diazido‐diborane gives a dicationic compound with a B 4 N 2 core. On the basis of experimental data in combination with quantum‐chemical calculations, pathways leading to these dicationic boron and boron‐nitrogen rings are suggested, and further preliminary studies demonstrate the scope of this strategy for the synthesis of polycationic boron‐nitrogen rings.