Twofold and Threefold Sinusoidal Patterns in Coupled Molecular Motions of 184,025 Structures of Phenylethane,...

Scatter plot analyses for 14,169 phenylethanes of the substructure C_β-C_αH₂-Ph with three open coordination positions at C_β and 150,568 phenylethanes of C_β-C_αHX-Ph with an additional open coordination position X at C_α have been performed, based on searches in the Cambridge Structural Database. The correlation of rotation angle ψ = C_β-C_α-C_i-C_o with a pyramidalization angle θ = C_o-C_o'-C_i-C_α in a 360° rotation about the bond C_α-C_i reveals a sinusoidal pattern with three maxima and minima, whereas the correlation of rotation angle ψ with bond angle ω = C_β-C_α-C_i and bond length d = C_β-C_α results in sinusoidal patterns with two maxima and minima. A total of 3993 nitro derivatives of the substructure C_β-C_αHX-NO₂ confirm the results and show that atoms C_i/C_o/C_o' in the phenyl compounds can be replaced by atoms N/O/O' without any change in the two- and threefold patterns. In 15,295 methyl acetates of the substructure C_β-C_αHX-C'(═O)OMe, pyramidalization of the group C_αC'(═O)OMe results in a chiral flat tetrahedron with four different corners. (R_θ)/(S_θ) selectivity in the configuration of the tetrahedron is induced by the bonds C_α-C_β, C_α-H, and C_α-X, emanating from the tetrahedral center C_α. It is surprising that bonds as different as C_α-C_β, C_α-H, and C_α-X (X = H, C, N, O, S, etc.) give almost the same induction intensities.