β-卤素取代对杯[4]吡咯构象及主-客体相互作用的影响(Ⅰ)——分子力学/分子动力学研究

通过分子力学/分子动力学模拟,获得4种游离杯4]吡咯以及杯4]吡咯-卤素阴离子主-客体复合物的稳定构象,用偶极子模型解释了β位卤素取代对游离杯4]吡咯稳定构象、杯4]吡咯-卤素阴离子复合物的结构及其结合能的影响,指出造成这些影响的主要因素是不同卤素取代导致杯4]吡咯的吡咯环基团偶极大小不同.计算了不同杯4]吡咯与卤素阴离子的结合能,当杯4]吡咯β位上的H原子被卤素阴离子取代后,杯4]吡咯对阴离子的识别能力加强.

Effects on the Conformations and Host-guest Interaction of Calix[4]pyrroles Substituted by Halide on β Positions( Ⅰ ) -- Molecular Mechanics/Molecular Dynamics Study

The calix4]pyrroles are new heterocalixarene analogues that show interesting anion and neutral substrate binding properties. In this paper, a series of molecular mechanics and molecular dynamics simulations were performed to obtain stable conformations of four free calix4]pyrroles and their corresponding host-guest complexes with halide anions; A dipole model was provided to explain how the substitutions by halide on β positions affected the conformations and host-guest interaction of calix4]pyrroles. These effects was due to the difference of dipole moments in pyrroles rings. Binding energies of the calix4]pyrrole-halide anion complexes were calculated. Replacing the β-pyrrolic hydrogens by halide atoms served, respectively, to greatly increase the anion binding affinities.