Host–Guest Complexation of Amphiphilic Molecules at the Air–Water Interface Prevents Oxidation by Hydroxyl Radicals and Singlet Oxygen. (25th May 2020)

• Record Type: Journal Article
• Authors: Geng, Wen‐Chao; Zhang, Dongmei; Gong, Chu; Li, Zhihao; Barraza, Kevin M.; Beauchamp, Jesse L.; Guo, Dong‐Sheng; Zhang, Xinxing
• Is Part Of: Angewandte Chemie. Volume 132:Number 31(2020)
• Page Start: 12784
• Page End: 12788
• Publication Date: 2020-05-25
• Subjects: antioxidants -- air–water interface -- calixarenes -- host–guest complexes -- mass spectrometry; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202001355
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The oxidation of antioxidants by oxidizers imposes great challenges to both living organisms and the food industry. Here we show that the host–guest complexation of the carefully designed, positively charged, amphiphilic guanidinocalix[5]arene pentadodecyl ether (GC5A‐12C) and negatively charged oleic acid (OA), a well‐known cell membrane antioxidant, prevents the oxidation of the complex monolayers at the air–water interface from two potent oxidizers hydroxyl radicals (OH) and singlet delta oxygen (SDO). OH is generated from the gas phase and attacks from the top of the monolayer, while SDO is generated inside the monolayer and attacks amphiphiles from a lateral direction. Field‐induced droplet ionization mass spectrometry results have demonstrated that the host–guest complexation achieves steric shielding and prevents both types of oxidation as a result of the tight and "sleeved in" physical arrangement, rather than the chemical reactivity, of the complexes. Abstract : A coating with "sleeves" : The compact host–guest complexation of calixarene and oleic acid molecules prevents the oxidation of the complex monolayers at the air–water interface by the action of hydroxyl radicals and singlet oxygen.