Theoretical Studies on Structures and Electronic State of Alkyl-Substituted Ethyl Cations

Table 5

Total energies 𝐸_total (Hartree) of alkyl-substituted ethyl cations 1–11 and reaction energies (kcal/mol) of corresponding isodesmic reactions^a.

Cation	R^1	R^2	R^3	R^4	R^5	𝐸total	Alkane	𝐸total	Δ𝐸iso
1	H	H	H	H	H	−78.2804	1–H	−79.1823	31.75
2	H	H	H	H	H	−78.2785	1–H	−79.1823	30.56
3	Me	H	H	H	H	−117.339	3–H	−118.200	57.11
4	Me	Me	H	H	H	−156.380	4–H	−157.220	70.59
5	H	H	Me	H	Me	−156.323	5–H	−157.220	34.83
6	H	Me	H	Me	H	−156.353	6–H	−157.219	54.28
7	Me	H	H	Me	H	−156.351	6–H	−157.219	53.02
8	Me	H	H	Me	H	−156.347	6–H	−157.219	50.51
9	Me	Me	Me	Me	H	−234.418	9–H	−235.251	74.99
10	Me	Me	H	Me	Me	−234.407	9–H	−235.251	68.08
11	Me	Me	Me	Me	Me	−273.433	11–H	−274.265	75.61

aThe structural optimizations and total energies 𝐸_total (Hartree) of methane and methyl cation were separately carried out at the same basis sets, respectively.