Theoretical investigation of the conventional CX1X2− (X1, X2 = H, F, Cl, Br, and I) compounds

The effects of substituents have been evaluated in detail via investigating on the electronic and molecular structures of the compounds constructed by model CX1X2− (X1, X2 = H, F, Cl, Br, I) using the DFT-B3LYP, MP2 and QCISD(T) methods with the aug-cc-pVTZ/RECP basis set. Comparisons are performed for the geometries of each compound CX1X2−, as well as with the analogous silicon-anion SiX1X2−. Moreover, the spin density (Sd) and second-order perturbative (E(2)) analysis are discussed to assess stabilization of these radical anions CX1X2−, suggesting the heavier the substituent, the stronger the stability is. Besides, we also estimated the ionization energies (IE) and proton affinity (PA) of the title anions and explored the difference between them for the same compound molecule.