title: Survey on the complexation character of p-sulfonatocalix[n]arenes and Caffeic acid.
abstract: In this work the inclusion complex formation of Caffeic acid (CA) with p-sulfonatocalix[n]arenes (SCXn, n=4, 6, 8) is reported aiming to improve the antioxidant activity, thermal stability and photostability properties of CA. Evidence for the formation was obtained using fluorescence spectroscopy, nuclear magnetic resonance spectroscopy (NMR), pulsed field gradient NMR (PFG-NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and scanning electron microphotographs (SEM). Experimental conditions including concentrations of SCXn and pH were investigated for the inclusion formation in detail. The results showed that CA was able to form inclusion complexes with SCXn in a molar ratio of 1:1, and the formation constants were varied with the pH conditions. NMR spectroscopy indicated that both the aromatic ring and the vinyl group of CA were partially covered by SCXn.
authors.affiliation: The Institute of Applied Chemistry of Shanxi University, Taiyuan 030006, China. Electronic address: chao@sxu.edu.cn.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Chao
authors.affiliation: The Institute of Applied Chemistry of Shanxi University, Taiyuan 030006, China; School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: The Institute of Applied Chemistry of Shanxi University, Taiyuan 030006, China; School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: First Clinical Hospital of Shanxi Medical University, Taiyuan 030006, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Second Clinical Hospital of Shanxi Medical University, Taiyuan 030006, China.
authors.forename: Bingtai
authors.initials: B
authors.lastname: Zhang
mesh_terms: D000975:Antioxidants / Q000032:analysis; D001713:Biphenyl Compounds / Q000737:chemistry; D002109:Caffeic Acids / Q000737:chemistry*; D047250:Calixarenes / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D016166:Free Radical Scavengers / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010851:Picrates / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D012996:Solutions; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D002109:Caffeic Acids; D016166:Free Radical Scavengers; D010851:Picrates; D012996:Solutions; D047250:Calixarenes; C004931:1,1-diphenyl-2-picrylhydrazyl; C040048:caffeic acid
keywords: Antioxidant activity; Caffeic acid; Inclusion complex; Photostability; Thermal stability; p-Sulfonatocalix[n]arenes