Effect of ring strain on disulfide electron attachment

The possibility of excess electron binding of a series of (bi)cyclic, ring-constrained disulfides, in gas phase was investigated by ab initio MP2/6-31+G∗∗ calculations. It is shown that ring strain favors electron attachment, as neutral compounds are very sensitive to angular and dihedral compressions: cyclic disulfides will preferentially undergo a spontaneous electron capture compared to linear analogs, with superior positive values for adiabatic electron affinity. Cyclisation effect is progressively switched off for higher-member rings, but remains important for disulfides grafted on molecular bridges. Its structural consequences are analysed, with different behaviors for neutral and radical anionic moities.