Quantum-chemical study of the interactions of π-orbitals of double bonds in divinyl compounds

Conclusions

• 1. The results of quantum-chemical calculations for divinyl compounds with bridging groups XR_n (X=C, N, O, Si, Ge, Sn) show that the interaction of the π orbitals of the double bonds through the covalent bond X-C becomes weaker on increasing the covalent radius of the hetero-atom X, on introducing electronegative substituents R, and also on passing from a planar to a “twisted” molecular conformation.

• 2. A weakening of the “conductivity” of the bridge is correlated with a decrease in the bond order of the X-C π bonds for the MO localized on the hetero-atom X and on the C atoms of the vinyl fragments covalently bonded to it, while the relative position of the frontier π MO on the energy scale is determined by the overlap occupancy of the corresponding π levels of the X-C bond.