Versatile Synthesis of Chlorophylls and Bacteriochlorophylls for Fundamental Studies in Photosynthesis

化学部化学合成计划支持乔纳森·S·林赛教授的项目。林赛教授是北卡罗来纳州立大学化学系的教员。他正在开发一种方法，在实验室用简单的起始材料以直接的方式创造叶绿素和细菌叶绿素(自然界用来从光中获取能量的分子)。(细菌)叶绿素的合成从来没有以这种方式完全完成。与类似物一起构建这种分子的能力将使人们更深入地了解光合作用中的能量流动(影响生物物理、植物科学、能源产生的领域)、代谢分解产物的性质(影响生态、全球碳平衡的领域)以及此类化合物的化学性质(影响营养、药物的领域)。该项目主要涉及有机化学，但也将影响科学的各个领域，包括对光合作用的理解。因此，该项目非常适合在协作环境中对科学家进行教育和培训。林赛教授的团队处于有利地位，可以为科学界代表性不足的学生提供这种体验。此外，涉及北卡罗来纳州教师的外联活动也将是资助项目的一部分。叶绿素和细菌叶绿素是光合作用生物中的主要色素，包括植物、蓝藻和缺氧光合细菌。缺乏制备(细菌)叶绿素及其类似物的合成方法构成了光合作用科学中的智力和技术缺陷。林赛实验室建议通过开发合成这种有价值的大环的可靠方法来填补这一鸿沟。合成(细菌)叶绿素的特殊挑战包括(1)吡咯环上取代基的立体化学(S)，(2)第五个(同环)环上的取代基，以及(3)排列在大环周围的取代基。这项工作的学术价值涉及关键光合色素及其类似物合成路线的开发；后者具有广泛的影响(超出本拨款的范围)，包括光合作用中的量子一致性和生态学中的分解代谢的研究。一个关键的成果是在杂环化学中制备与光合作用的(细菌)叶绿素相关的吡咯、吡咯烷、二吡咯甲烷、氢二吡咯和叶绿素的方法学。更广泛的影响包括中学和高中科学教师的专业发展，以改善学校的光合作用教学(通过基于叶绿素的实验)，并激励初中生参加STEM，从而扩大代表不足的群体的参与。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Chemical Synthesis Program of the Chemistry Division supports the project by Professor Jonathan S. Lindsey. Professor Lindsey is a faculty member in the Department of Chemistry at North Carolina State University. He is developing methods to create chlorophylls and bacteriochlorophylls (molecules that nature used to harvest energy from light) in the laboratory from simple starting materials in a straightforward manner. The synthesis of (bacterio)chlorophylls has never been fully accomplished in this manner. The ability to build such molecules along with analogues will afford a much deeper understanding of energy flow in photosynthesis (an area that impacts biophysics, plant sciences, energy generation), the nature of metabolic breakdown products (an area that impacts ecology, global carbon balance), and the chemical properties of such compounds (an area that impacts nutrition, medicine). The project mainly involves organic chemistry but will also impact diverse areas of science including understanding of photosynthesis. Thus, the project is well suited for the education and training of scientists in a collaborative environment. Professor Lindsey's group is well-positioned to provide this experience for students underrepresented in science. In addition, outreach activities involving North Carolina teachers will also be part of the funded project. Chlorophylls and bacteriochlorophylls are the chief pigments in photosynthetic organisms, including plants, cyanobacteria, and anoxygenic photosynthetic bacteria. The lack of synthetic methods for preparing (bacterio)chlorophylls and analogues constitutes an intellectual and technical deficit in the photosynthetic sciences. The Lindsey lab proposes to fill this chasm by developing robust methods for synthesis of such valuable macrocycles. The particular challenges in synthesizing (bacterio)chlorophylls include (1) the stereochemistry of substituents in the pyrroline ring(s), (2) the fifth (isocyclic) ring, and (3) substituents arrayed about the perimeter of the macrocycle. The intellectual merit of the work concerns the development of routes for the synthesis of the key photosynthetic pigments and analogues; the latter have broad impact (beyond the scope of the present grant) encompassing studies of quantum coherence in photosynthesis and catabolism in ecology. A key outcome is a methodology in heterocyclic chemistry for preparing pyrroles, pyrrolines, dipyrromethanes, hydrodipyrrins, and phyllobilins relevant to the (bacterio)chlorophylls of photosynthesis. The broader impacts entail professional development of middle and high school science teachers to improve teaching of photosynthesis (via a chlorophyll-based experiment) in schools and to inspire middle and high school students to STEM, thereby broadening the participation of underrepresented groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.