Table 2.

Relative energies in (kJ mol⁻¹) calculated at the B3LYP/6-311 + G(d,p) theory level and populations in (%) of the styrylpyridine-like model compounds (IIIa–IIIc) for different rotamers, with θ1 and θ2 dihedral angles in (°).

2-Styrylpyridine			IIIa
θ1, θ2	Relative energy	Population	θ1, θ2	Relative energy	Population
0.0, 0.0	0.000	11.847	0.0, 0.0	0.000	6.854
0.0, 180.0	4.647	1.797	0.0, 180.0	6.459	0.076
30.0, 30.0	8.113	0.087	30.0, 30.0	7.903	0.064
60.0, 60.0	31.821	0.002	60.0, 60.0	31.532	0.001
90.0, 0.0	20.033	0.008	90.0, 0.0	19.088	0.003
90.0, 90.0	45.815	0.000	90.0, 90.0	45.658	0.000
90.0, 180.0	25.074	0.009	90.0, 180.0	24.916	0.003
180.0, 0.0	0.000	11.847	180.0, 0.0	0.630	5.254
180.0, 180.0	4.647	1.797	180.0, 180.0	5.277	1.231
IIIb			IIIc
θ1, θ2	Relative energy	Population	θ1, θ2	Relative energy	Population
0.0, 0.0	0.000	6.581	0.0, 0.0	0.000	5.246
0.0, 180.0	6.091	0.011	0.0, 180.0	0.053	4.348
30.0, 30.0	7.850	0.025	30.0, 30.0	2.757	0.077
60.0, 60.0	31.296	0.007	60.0, 60.0	19.770	0.004
90.0, 0.0	19.114	0.005	90.0, 0.0	18.168	0.002
90.0, 90.0	45.290	0.001	90.0, 90.0	33.712	0.001
90.0, 180.0	24.627	0.013	90.0, 180.0	25.074	0.005
180.0, 0.0	0.525	5.541	180.0, 0.0	0.000	5.056
180.0, 180.0	5.094	0.897	180.0, 180.0	0.053	4.348