BRIGE: Redox Noninnocent Ligands - Application to the Reductive Transformation of Veterinary Pharmaceuticals Containing Carbon-Nitrogen Double Bonds

主要研究者：研究目的和方法：氧化还原非无辜配体（Redox non-innocent ligands，RNILs）是无机化学家们研究的一个热点，它与许多过渡金属形成的配合物具有氧化还原性质。然而，关于RNILs的氧化还原活性的信息很少，特别是当它涉及到新兴污染物的命运和转化时。另一方面，可溶性Fe（II）与有机cathechol-和硫醇-配体的配合物，在文献中仅被认为是氧化还原配体，最近已被认识到它们能够减少许多有机污染物。考虑到Fe（II）络合物在环境中的普遍存在和快速氧化还原反应性，缺乏对配体性质的理解（.，氧化还原无害对非无害）将显著妨碍对还原环境中出现的污染物的命运和转化的准确估计。因此，本研究将应用氧化还原非无辜配体的概念来研究一类含碳-氮双键的兽药（VP）的整体还原转化; VP和RNILs的作用和转化将从机理的角度进行研究。基于我们的初步结果和文献，我们假设这组VP将进行快速氧化还原反应与Fe（II）配合物与一些RNILS，包括邻苯二酚，邻二氨基苯，邻氨基苯酚，邻二硫纶，邻氨基硫醇配体。为了验证这一假设，一系列的实验已经构建（1）来说明氧化还原非无辜的性质的复合物，（2）以确定所选择的VP和结构相关的模型化合物的反应动力学和机制，（3）开发定量结构活性关系（QSAR），可用于预测其他结构相似的污染物的还原转化。在方法学上，该研究将依赖于多种方法，包括但不限于循环伏安法、FTIR、HPLC、LC-MS-MS、NMR和UV-可见光测量与分析测定相结合。智力优点：这项研究是第一个研究环境相关的Fe（II）络合物的氧化还原非无害行为。先进的实验和解释方法将用于生成知识，这对于准确建模一组重要的含有碳-氮双键的VP的环境命运至关重要，这也是许多其他新兴污染物（如人类药物和个人护理产品和农药）的常见结构部分。该项目的智力价值是基于：1）对一些Fe（II）络合物的氧化还原非无害行为的基本理解; 2）对络合物和一组VP之间的还原反应的机理理解;和3）可用于估计VP之外的其他结构相关污染物的命运的QSAR的发展。在该项目的基础上，PI将能够系统地研究许多其他金属（II）-RNIL络合物在各种新兴污染物的命运和转化中的作用。更广泛的影响：环境科学家/工程师可利用该项目的结果开发环境归趋模型，以准确预测氧化还原活性环境中有机污染物的归趋和转化。 此外，该项目将有助于我们的研究生、本科生和高中生的培训、指导和全面发展。将特别鼓励代表性不足的少数民族学生和女学生参加与开创性的CEET（化学促进环境-教育和培训）方案、女工程师协会分会、大学？的高级设计课程，联盟少数民族参与计划，为期一周的住宅夏季计划“妇女的工程探索”和部门？每周的研讨会。本研究的结果和技术将通过讲座，实验和演示相结合，融入坦普尔大学的环境课程。此外，该项目的研究结果将在坦普尔大学水和环境技术中心的年度工业咨询委员会会议上广泛传播给30多个工业伙伴。

PI: Zhang, Huichun J.Proposal Number: 1125713Research Objectives and Approach: Redox noninnocent ligands (RNILs) have been extensively studied by inorganic chemists on the redox-nature of the complexes formed with many transition metals. Yet, little information is available regarding the redox activity of RNILs, particularly as it pertains to the fate and transformation of emerging contaminants. On the other hand, soluble Fe(II) complexes with organic cathechol- and thiol-ligands, considered only as redox ligands in the literature, have been recently recognized for their ability to reduce a number of organic contaminants. Given the ubiquitous presence and fast redox reactivity of Fe(II) complexes in the environment, this lack of understanding of the nature of the ligands (., redox innocent versus noninnocent) will significantly prevent accurate estimation of the fate and transformation of emerging contaminants in reducing environments. For this reason, the proposed study will apply the concept of redox noninnocent ligands to the overall reductive transformation of a group of veterinary pharmaceuticals (VPs) containing carbon-nitrogen double bonds; the role and transformation of both the VPs and RNILs will be investigated from mechanistic perspective. Based on our preliminary results and the literature, we hypothesize that this group of VPs will undergo fast redox reaction with Fe(II) complexes with a number of RNILs including -catecholate, o'diaminophenylene, o-aminophenolate, o-dithiolene, and o-aminothiolate ligands. To test this hypothesis, a series of experiments have been structured (1) to illustrate the redox noninnocent nature of the complexes, (2) to determine the reaction kinetics and mechanism of the selected VPs and structurally related model compounds, and (3) to develop quantitative structural-activity relationships (QSARs) that can be used to predict reductive transformation of other structurally similar contaminants. Methodologically, the study will rely on diverse methods including but not limited to cyclic voltammatry, FTIR, HPLC, LC-MS-MS, NMR, and UV-visible measurements coupled with analytical determinations. Intellectual Merit: This study is one of the first to examine the redox noninnocent behavior of environmentally relevant Fe(II) complexes. Advanced experimental and interpretative methods will be used to generate knowledge that is critical for accurate modeling of environmental fates of an important group of VPs containing carbon-nitrogen double bonds, which are also a common structural moiety for many other emerging contaminants such as human pharmaceutical and personal care products and pesticides. The intellectual merit of this project is based on: 1) fundamental understanding of the redox noninnocent behavior of a number of Fe(II) complexes; 2) mechanistic understanding of the reduction reaction between the complexes and a group of VPs; and 3) development of QSARs that can be used to estimate the fate of other structurally related contaminants beyond VPs. On the basis of this project, the PI will be able to systematically study the role of many other metal(II)-RNIL complexes in the fate and transformation of a variety of emerging contaminants. Broader Impacts: Results of this project can be used by environmental scientists/engineers to develop environmental fate models to accurately predict the fate and transformation of organic contaminants in redox-active environments. Moreover, this project will contribute to training, mentoring and overall development of our graduate, undergraduate and high school students. Underrepresented minority and female students will be particularly encouraged to participate through a variety of activities planned with the pioneering CEET (Chemistry for the Environment - Education and Training) program, the Chapter of the Society of Women Engineers, College?s senior design course, Alliance For Minority Participation program, one-week residential summer program "Women's Engineering Exploration" and Department?s weekly seminars. Results and techniques of this study will be integrated into the environmental curriculum at the Temple University through a combination of lectures, experiments and demonstrations. In addition, findings from this project will be broadly disseminated to over 30 industrial partners at the annual industrial advisory board meetings of the Water and Environmental Technology (WET) Center at the Temple University.