Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
Org Lett. 2011 Aug 19;13(16):4320-3. doi: 10.1021/ol201657p. Epub 2011 Jul 28.
A series of conformationally flexible bicyclic N-arylimides were employed as molecular balances to study the weak aliphatic CH-π interaction between alkyl and arene groups. The formation of intramolecular CH-π interactions in the folded conformers was characterized by X-ray crystallography. The strengths of the interactions were characterized in CDCl(3) by the changes in the folded/unfolded ratios, as measured by (1)H NMR. The CH-π interaction between a methyl group and an aromatic surface was ∼1.0 kcal/mol and was easily disrupted or masked by conformational entropy and repulsive steric interactions.
一系列构象灵活的双环 N-芳基酰亚胺被用作分子天平，以研究烷基和芳基基团之间的弱脂肪族 CH-π 相互作用。通过 X 射线晶体学表征了折叠构象中分子内 CH-π 相互作用的形成。通过（1）H NMR 测量折叠/未折叠比例的变化，在 CDCl(3)中表征相互作用的强度。甲基和芳环表面之间的 CH-π 相互作用约为 1.0 千卡/摩尔，很容易被构象熵和排斥性空间相互作用破坏或掩盖。
