Carbone-type Reactivity by a Neutral Antimony(I) Compound in Bond Activation and Catalysis

Carbones, bis(donor)-stabilized carbon(0) species, are renowned for their exceptional donor strength, di-nucleating ligand property, and bond activation ability, but parallel reactivity of valence-isoelectronic heavy pnictogens analogues has remained elusive. We report a neutral, two-coordinate Sb(I) compound supported by a bis(carbene)borate (BCB) ligand, representing a rare antimony analogue of carbones. Single-crystal X-ray diffraction and computational analyses establish a two-coordinate nature of Sb(I) center and two non-bonding electron pairs, respectively. This compound provides exceptional donor strength (Tolman electronic parameter, TEP = 2040 cm ^–1 ) close to that of carbone ligands, di-nucleating coordination to two Pd(II) centers, and cooperative bond activation in combination with B(C ₆ F ₅ ) ₃ enabling C–F and C–O bond cleavage. Furthermore, the neutral Sb(I) species catalyzes radical type 1,2-iodoperfluoroalkylation of alkenes under photochemical conditions, highlighting its potential in radical organocatalysis. These findings establish a design principle for stabilizing neutral low-valent pnictogens with true carbone-like reactivity and open avenues for main-group catalysis that parallels transition-metal chemistry.