Five Regioisomers of Dimethyl Dodecahedrane Derivatives: A Hybrid DFT B3LYP Study

Table 1

The relative energies (rel. ), relative ZPEC energies (rel. ZPEC), relative enthalpy (rel. ), and relative Gibbs free energies (rel. ) in units of meV and distance (, Å) between the two methyls of the five C₂₀H₁₈(CH₃)₂ derivatives using B3LYP/6-31G(d, p) calculations.

Derivative	Rel.	Rel. ZPEC
1,2-cis-1	112.7	121.6	3	9	2.88
1,4-cis-2	2.9	2.5	−3	−5	4.32
1,7-eq	0.8	0.4	−2	−2	6.11
1,6-trans-2	1.9	0.2	−4	−7	6.99
1,16-trans-1	0.0	0.0	0	0	7.48

The relative value of each derivative is the energy minus the energy of trans-1 isomer.