Table II.
Interaction geometries for methylammonium ions interacting with benzene, after constrained optimization using the aug-cc-pVTZ without f functions basis set and M06−2X functional. R refers to the distance between the ammonium nitrogen and the center of the benzene ring, θ refers to the angle between the ammonium nitrogen and the axial to the ring, and ϕ refers to where the cation is positioned with respect to the benzene hydrogen atoms.
| Initial Geometry θ_ϕ |
NH4+ | CH3NH3+ | (CH3)2NH2+ | (CH3)3NH+ | (CH3)4N+ | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| R(Å) | ϕ | R(Å) | ϕ | R(Å) | ϕ | R(Å) | ϕ | R(Å) | ϕ | |
| 0_0 | 2.9 | - | 3.0 | - | 3.0 | - | 3.0 | - | 4.2 | - |
| 30_0 | 3.4 | 5-10 | 3.5 | 20-25 | 3.5 | 25-30 | 3.5 | 25-30 | 4.3 | 0-5 |
| 30_30 | 3.5 | 10-15 | 3.4 | 5-10 | 3.5 | 5-10 | 3.6 | 25-30 | 4.4 | 0-5 |
| 60_0 | 4.1 | 25-30 | 4.2 | 25-30 | 4.1 | 25-30 | 4.2 | 25-30 | 5.1 | 25-30 |
| 60_30 | 4.1 | 25-30 | 4.2 | 25-30 | 4.2 | 25-30 | 4.2 | 25-30 | 5.2 | 25-30 |
| 90_0 | 4.4 | 25-30 | 4.4 | 25-30 | 4.6 | 25-30 | 4.6 | 25-30 | 8.0 | 15-20 |
| 90_30 | 4.4 | 25-30 | 4.4 | 25-30 | 4.6 | 25-30 | 4.6 | 25-30 | 6.4 | 25-30 |