Experimental and computational investigations on the high binding-selectivity of pyrimidine derivatives by a pillar[5]arene.

The binding selectivity of an adenine-monofunctionalized pillar[5]arene (H) with a series of pyrimidine derivatives were investigated through 1H NMR experiments and density functional theory (DFT) study. High binding-selectivity was demonstrated. Typically, H displayed very strong binding strength with 6-(2,4-dioxo-3, 4-dihydropyrimidin-1 (2H)-yl)hexanenitrile (G1) [Ka >105 M−1], up to about 3000-fold as compared with 1-hexylpyrimidine-2,4(1H, 3H)-dione (G5) [Ka = 31 M−1]. The strong binding ability of H with G1 was due to the cooperative multiple hydrogen bond, dipole-dipole, C-H···π and π···π interactions. The high binding-selectivity was also verified by calculation results. The calculated interaction energy (ΔEi) of G1⊂H was −12.92 Kcal·mol−1 while that of G5⊂H was −2.85 Kcal·mol−1. [ABSTRACT FROM AUTHOR]