Isolation and Properties of the Long Elusive Deep Blue Soluble [K(3){(N( t )Bu)(3)S}(2)](.) Cage Radical

The reaction of potassium metal with sulfurtriimide S(N( t )Bu)(3) (II) gives the long elusive deep blue cage radical [K( 3 ){(N( t )Bu)( 3 )S}( 2 )](.) (1_K) that crystallizes at −35 °C from toluene solution. The subsequent physical characterization via X‐ray structure analysis, UV/Vis‐, and EPR spectroscopy from solution reveals the existence of one unpaired electron delocalized within the whole cage, i.e. coupling with the six nitrogen atoms, as well as the three potassium atoms caped by the two SN(3) ligands. The present X‐ray structure analysis further supports previous assumptions made on the parent compound 1_Li obtained from [Li(4){(N( t )Bu)(3)S}(2)] (I) and finally elucidates the structural arrangement of the SN(3) caps and alkali metals in such radical cage species.