Diarylstannylene Activation of Hydrogen or Ammonia with Arene Elimination

Treatment of the stannylenes SnAr'2 (Ar' = C6H3-2, 6 (C6H3-2, 6-Pri2) 2), SnAr2# (Ar# = C6H3-2, 6- (C6H2-2, 4, 6-Me3) 2, or SnN (SiMe3) 22 with H2, D2, or NH3 under identical, mild (1 atm, 65 degrees C) conditions showed that SnAr2' reacted readily to afford the products Ar'Sn (mu-H) 2, Ar'Sn (mu-D) 2, or Ar'Sn (mu-NH2) 2 with elimination of Ar'H or Ar'D. The less crowded stannylenes SnAr2# and SnN (SiMe3) 22 were recovered unreacted. The differences in reactivity were accounted for in terms of the n-p energy separations which is lowest in the case of AnAr2'. The low energy separation in SnAr' is consistent with enhanced singlet diradical character of the ground state which increases its reactivity.