Theoretical descriptions of novel bicyclic stannylenes and their halogenated derivatives

The effect of halogen substituents on the stability and reactivity of singlet (s) and triplet (t) forms of novel bicyclic stannylenes ( 1 – 10 ) with one and two stannylene centers are compared and contrasted, at B3LYP/6-311++G** and M06/Def2-TZVP level of theories. All bicyclic stannylenes appear singlet ground state and the highest and lowest stability belong to 2 (Δ E s − t = 95.29 kcal/mol) and 7 (13.90 kcal/mol), respectively. The order of stability based on the absolute values of Δ E s − t in kcal/mol is 2 > 4 > 3 > 5 > 1 > 9 > 10 > 6 > 8 > 7 at the two level of theories. This clearly demonstrates the effect of our imposed structure and intermolecular interactions. The LP (F, Cl, Br, and I) → LP ∗ S ¨ n interactions and LP S ¨ n →σ * (C–F, Cl, Br, and I) interactions have positive and negative effect on stability, respectively. For example, competition between LP (Br(exo)) → LP ∗ S ¨ n (positive effect) and LP S ¨ n →σ * (C–Br) (negative effect) interaction at stannylene 4 s leads to a decrease in their stability than 3 s . In fact, this study offers novel stannylene 1 s with rather high stability (Δ E s − t = 37.45 kcal/mol), nucleophilicity (3.76 eV), and high negative Δ E PA (− 258.80 kcal/mol) that can be applied as accumulated ligand. Graphical abstract