Mokhtar Maali Saad, Suliman FakhrEldin O, Elbashir Abdalla A
Department of Chemistry, College of Science, Sultan Qaboos University, Box 36, Al-Khod 123, Oman; Department of Chemistry, Box 321, Faculty of Science, Khartoum University, Khartoum, Sudan.
Department of Chemistry, College of Science, Sultan Qaboos University, Box 36, Al-Khod 123, Oman.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Apr 5;194:67-75. doi: 10.1016/j.saa.2018.01.007. Epub 2018 Jan 4.
The inclusion complexes of imazapyr (IMA) with cucurbit[n]uril, CB[n] (n=6-8), have been investigated. Fluorescence spectroscopy, MALDI-TOF, and HNMR were used to investigate and characterize the inclusion complexation of IMA and CB[n] in solutions. Whereas the solid state complexes have been characterized by Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). IMA was found to form 1:1 complexes with CB[n] with association constants ranging from 5.80×10-2.65×10. The guest molecule IMA was found to encapsulate into the larger cavities of CB[7] and CB[8], whereas with CB[6] the molecule remains outside the cavity. Molecular dynamic (MD) simulations were used to follow the inclusion process at an atomistic level to study the mechanism and stability of inclusion. The results obtained showed that inclusion complexes of IMA with both CB[7] and CB[8] are highly stable in aqueous media, but the CB[6] smaller cavity size prohibited the formation of an inclusion complex with IMA. The results clearly show that in addition to hydrophobic effects the presence of hydrogen bonding has added greatly to the stability of these complexes.
已对咪草烟（IMA）与葫芦[n]脲（CB[n]，n = 6 - 8）的包合物进行了研究。利用荧光光谱、基质辅助激光解吸电离飞行时间质谱（MALDI - TOF）和核磁共振氢谱（HNMR）对溶液中IMA与CB[n]的包合作用进行了研究和表征。而固态配合物则通过傅里叶变换红外光谱（FTIR）和粉末X射线衍射（PXRD）进行了表征。发现IMA与CB[n]形成1:1配合物，缔合常数范围为5.80×10 - 2.65×10。发现客体分子IMA包封在CB[7]和CB[8]的较大空腔中，而与CB[6]时该分子保留在空腔外部。利用分子动力学（MD）模拟在原子水平上跟踪包合过程，以研究包合的机理和稳定性。所得结果表明，IMA与CB[7]和CB[8]的包合物在水性介质中高度稳定，但CB[6]较小的空腔尺寸阻止了与IMA形成包合物。结果清楚地表明，除了疏水作用外，氢键的存在大大增加了这些配合物的稳定性。
