催化水解β-内酰胺键导致直接开环是消除水中头孢菌素类抗生素(CEPs)生物活性的有效手段之一。本项目利用铁(氢)氧化物矿物(IOM)具有特殊的组成、晶面和Fe自旋状态等性质，系统研究IOM在光照及暗反应下催化降解多种CEPs的反应。以7-氨基头孢烷酸/7-氨基去乙酰氧基头孢烷酸及3-甲基丁烯酸为CEPs分子结构模型化合物，利用同位素标记(H218O，D2O和18O2)、液质联用、电子顺磁技术，测定矿物(表面)对CEPs内酰胺键催化水解和氧化过程中的降解产物及氧化物种，捕捉β-内酰胺键断裂方式(水解/氧化)和进攻位点。同时结合原位红外光谱及穆斯堡尔光谱，研究IOM表面吸附对CEPs催化降解的机理；确定IOM(光)催化β-内酰胺键断裂的主要反应路径，明确光活化对表面Fe酸性的影响及其对β-内酰胺键亲核水解的选择性和活性；并利用DFT分子计算进一步研究CEPs内酰胺键断裂的普遍规律。

The direct cleavage of β-lactam ring by catalytic hydrolysis is believed to be an effective way for lowering the antibacterial activities of cephalosporin antibiotics (CEPs) in water. Here we select iron (hydr)oxide minerals (IOM) with defined composition, crystal plane and spin state of Fe as catalysts to achieve the degradation of several kinds of CEPs under solar/Vis irradiation and dark conditions. With 7-aminocephalosporanic acid/ 7-aminodesacetoxycephalosporanic acid and 3-methylcrotonic acid as structural model compounds of CEPs, utilizing isotope labeling technique, liquid chromatography-mass spectrometry (LC-MS) and spin-trapping electron spin resonance (ESR) to analyze the degradation products and oxidative species of IOM/CEPs system, and to determine the cleavage way of β-lactam bond (hydrolysis/oxidation) and reaction sites (18O, 2H source) of CEPs with different structures. Combining in-situ FTIR and Mossbauer spectrum (MS), to explore the underlying mechanism of the effect of CEPs adsorption on IOM surface-catalyzed reactions, to determine the main reaction pathways for IOM (photo)catalysis of β-lactam bond cleavage, and to explicit the effects of photoactivation on the surface Fe acidity and on the selectivity and activity of IOM during nucleophilic hydrolysis of β-lactam bond process. From the density functional theory (DFT) descriptors and the experimental results, we could further elucidate the cleavage rules of β-lactam bond at the IOM/water interface.