Homolytic Cleavage Reactions of a Neutral Doubly Base Stabilized Diborane(4)

The neutral doubly base stabilized diborane(4) [C2H2(NCH2C6H4)2CB]2 (3a), featuring an electron-precise B­(sp3)–B­(sp3) σ bond, was generated by one-electron reduction of the corresponding borenium precursor with Cp*2Co followed by dimerization. Compound 3a reacts with TEMPO, (PhC­(O)­O)2, PhNO, (tht)­AuCl (tht = tetrahydrothiophene), and S8. The resulting species, (C2H2(NCH2C6H4)2CB)­(L) (L = ONC5H6Me4 (4), OC­(O)­Ph (5), PhNO (6), Cl (7)) and [(C2H2(NCH2C6H4)2CB)2(S4)] (8), have been fully characterized and are consistent with homolytic cleavage of the B–B bond in 3a.