Thermodynamic Calculations for Reactions Involving Hydrogen Halide Polymers, Ions, and Lewis Acid Adducts. 2. Polychlorohydrogenate(1-) Anions (H_nCl_n+1^-), Polychlorohydrogen(I) Cations (H_n+1Cl_N⁺), and Hydrogen Chloride Polymers (HCl)_n

Semiempirical (MNDO, AM1, and PM3) and ab initio (HF/3-21+G(d,p), BVWN/3-21+G(d,p), MP2/3-21+G(d,p), HF/6-311+G(d,p), BVWN/6-311+G(d,p), and MP2/6-311+G(d,p)) energy minimization and frequency calculations have been carried out on three hydrogen chloride polymers, (HCl)_n, n = 2-4 (the semiempirical methods were employed for n = 5 and 6 as well); on four polychlorohydrogenate(1-) anions, H_nCl_n+1^-, n = 1-4; and on two polychlorohydrogen(I) cations, H_n+1Cl_n⁺, n = 1 and 2. From the results, ΔG°, ΔH°, and ΔS° values have been calculated for a number of reactions involving these species. The thermodynamic data are presented for 21 reactions using calculations at the MP2/6-311+G(d,p) level, along with a comparison of ΔG° values obtained from all nine molecular orbital methods. ¹H NMR shielding data have also been calculated for three species, HCl, HCl₂^-, and H₂Cl⁺, using the gauge-independent atomic orbital (GIAO) and the continuous set of gauge transformations (CSGT) methods and density functional techniques with large basis sets.