Hirshfeld surface and structural analysis of new crystal form of felodipine
Objective:To prepare a new crystal form(Form Ⅴ)of felodipine,analyze the molecular conformation,crystal stacking and hydrogen bond network of Form Ⅴ,and explore the intermolecular force difference and formation mechanism between Form Ⅰ and Form Ⅴ of felodipine.Methods:A new crystal form of felodipine(Form Ⅴ)was prepared by solvent slow evaporation method.The crystal parameters and three-dimensional structure of Form Ⅴ were obtained by single crystal X-ray diffraction.The intermolecular hydrogen bond forces of the two forms were analyzed by infrared spectroscopy,Raman spectroscopy and Hirshfeld surface analysis.Results:X-ray diffraction analysis showed that Form Ⅴ belongs to monoclinic system,P21/c space group,and each asymmetric unit contains a felodipine molecule.The unit cell parameters are:a =11.2528Å,b =9.6018Å,c =16.4019Å,β =92.688°.The results of Hirshfeld surface analysis showed that Form Ⅰ and Form Ⅴ have similar interaction force,H…H force is the main contribution,but there are differences among the magnitudes of the forces.Conclusion:Felodipine molecules are connected with carbonyl O atoms on methyl ester groups by N1-H1…O2 hydrogen bonds through pyridine N atoms.Hirshfeld surface analysis can reveal the interaction between molecules in the crystal structure intuitively and visually.
felodipinepolymorphismhydrogen bondHirshfeld surface analysisX ray diffraction analysis