【摘要】 以α-猪去氧胆酸为隔离基,在3位桥联不同的D,L-氨基酸甲酯作手性臂,采用微波辐射法,合成了具有不同手性中心和裂穴的新型分子钳受体,其结构均经1H NMR、IR及元素分析测试技术得以确证。采用紫外光谱滴定法考察了这些受体对D,L-氨基酸甲酯的识别性能。结果表明,这类分子钳受体对所考察的客体D/L-氨基酸甲酯具有良好的识别配合性能,主客体间形成1∶1型超分子配合物。根据Hildebrand-Benesi方程,以1/ΔA对1/[G]0作图,均得出良好的线性关系,由直线的斜率和截距计算出配合物的稳定常数(Ka),进而计算出相应的自由能变化(-ΔG0)。初步研究结果表明,这类分子钳受体由于在结构上的微环境改变,导致其对映选择性识别性能的差异。更多还原

【Abstract】 A novel type of molecular tweezers with different chiral center and cleft has been designed and synthesized with α-hyodeoxycholic acid as spacer and D/L-amino acid methyl ester as chiral arm attached at 3-position under microwave irradiation.Their structures were elucidated by 1H NMR,FTIR spectra and elemental analysis.Their molecular recognition properties for D/L-amino acid methyl esters were investigated by UV-Vis spectral titration,which showed that all these molecular clefts possessed a good recognition ability for D/L-amino acid methyl esters.The supramolecular complexes formed between the tweezers and various substrates consisted of a 1∶1 type of host to guest of molecules.Based on the Hildebrand-Benesi equation,plotting 1/ΔA vs 1/[G]0 gave a straight line.From the line slopes and intercepts,the stability constants(Ka) of the complexes were calculated and thereafter the correspondent Gibbs free energies(-ΔG0) were also obtained.Preliminary results indicate that due to the structural micro-environmental changes,the synthesized chiral single-armed molecular tweezers exhibit different enantio-selectivity for D/L-amino acid methyl esters.更多还原