At Organometallics, the Editorial Team has been highlighting a number of scientists that we feel have had a profound impact on the field and perhaps also on ourselves. In this editorial, I wish to introduce another of our Pioneers and Influencers, Professor Charlotte K. Williams from Oxford University. Professor Williams works on three things I love: homogeneous metal catalysts, carbon dioxide, and selectivity. With these ingredients, she is developing impressive protocols for making versatile and sustainable polymers. As a small-molecule chemist, I am in awe of scientists who embark on making polymers. Polymers often referred to as “plastics”, are large molecules composed of repeating subunits, and they have favorable properties, such as macroscale toughness, which shorter molecules are unable to provide. The current worldwide production of polymers is 360 million tons/year.(1) However, developing a polymerization catalyst that can produce polymers with exactly the desired physical–chemical properties is a magician’s work. As Williams and Nozaki write “In contrast to small-molecule catalysts, polymerization catalysts also control the polymerization rate, selectivity, and productivity that govern the resulting materials’ crystallinity, decomposition temperature, viscosity, rheology, and mechanical performance. Catalyst selection may also be used to tune the polymer molecular weight, dispersity, chain composition, chain architecture, and regio- and/or stereochemistry.”(2) Charlotte Williams (Figure 1) was born in 1975 and studied Chemistry at Imperial College London, from where she received a Bachelor’s Degree in 1998. During her Ph.D. studies (1998–2001), Williams worked with Vernon Gibson and Nicholas Long, initially embarking on classic organometallic chemistry with focus on ferrocenediyl ligands.(3) In fact, the first scientific article coauthored by Williams appeared in Organometallics, with the title “Hang-gliding with Ferrocenes: Unusual Coordination Chemistry of 1,1′-Bis(mesitylthio)ferrocene” (Figure 2).(3a) Figure 1. Professor Charlotte K. Williams. Figure 2. X-ray structure of the hang-glider-like C,S-cyclometalated Pt^IV complex formed from 1,1′-bis(mesitylthio)ferrocene (left)(3a) and a hang-glider (right).(4) The ferrocenediyl complexes were tested in Suzuki coupling and olefin polymerization catalysis.(3c,e) From then on the use of homogeneous catalysts in polymerization reactions became a defining topic in Williams’ work. During 2001–2002, she was a postdoctoral fellow, first studying lactide ring-opening polymerization (ROP) with William B. Tolman and Marc Hillmyer at the University of Minnesota, USA.(5) Subsequently she worked with organometallic light-emitting polymers, with Andrew Holmes and Richard Friend at the University of Cambridge, UK.(6) In 2003, Williams returned to her Alma Mater, Imperial College, as a lecturer. Here she started her independent career, with a focus on developing new homogeneous catalysts for polymerization reactions, initially focusing on yttrium complexes.(7) In 2004, CO₂ entered into her research as a potential polymer ingredient, due to Williams’ interest in developing polymers from sustainable feedstocks. However, initially all her attempts to develop an efficient catalyst for copolymerization of CO₂ failed, and several years without success passed by before her team finally could report a major breakthrough in 2009 (patented in 2008): a dizinc catalyst with a reduced Robson type macrocycle, which is able to copolymerize CO₂ and cyclohexene oxide (Figure 3).(8) Williams was not the first to copolymerize CO₂ and epoxides; indeed, the first reaction of this type, mediated by ZnEt₂, was developed in 1969 by Inoue and co-workers.(9) This was followed by seminal studies leading to well-defined homogeneous zinc catalysts reported by the groups of Darensbourg,(10) Coates,(11) and Lee,(12) among others.(13) However, Williams’ catalyst was a remarkable step forward due to its properties: robust, air-stable, with high end-group fidelity and, most important, the first well-defined zinc catalyst that was highly active at only 1 atm of CO₂ pressure.(8) Figure 3. (top) Copolymerization of CO₂ and cyclohexene oxide (CAT = catalyst). (bottom) Bimetallic Zn catalyst reported by Williams in 2009 (left)(8) and X-ray structure of the Co-analogue reported in 2010 (right).(14) The Williams group reported a bimetallic cobalt analogue in 2010 (Figure 3, right), which was even more active and selective than the zinc catalyst, producing no cyclic carbonate as an undesired byproduct.(14) This was later followed by the first homogeneous heterodinuclear Zn/Mg catalyst with improved performance for CO₂–epoxide copolymerization, still with the reduced Robson ligand.(15) If Williams’ initial work is described as involving the synthesis of a hang-glider complex (Figure 2), then I suggest considering these beautiful macrocyclic catalysts as her follow-up jet planes (Figure 3). The catalysts’ excellent performance may be due to the two metals in proximity, as the polymer chain growth is expected to occur through a shuttle mechanism involving both metal centers (Figure 4).(15) Figure 4. Proposed bimetallic shuttle mechanism for ring-opening copolymerization (ROCOP) of cyclohexene oxide and CO₂ (based on the mechanism shown in ref (15)). In 2009, Williams became a Reader at Imperial College, which can be considered equivalent to an Associate Professor. In 2011, she received the BioEnvironmental Polymer Society Outstanding Young Scientist Award for her work,(16) and in 2012 she became Professor of Catalysis and Polymer Chemistry at Imperial College.(17) Prof. Williams continued to perform polymer magic and reported in 2014 a novel control mechanism that allows switching a single catalyst between the ROP of lactones and ring-opening copolymerization (ROCOP) of epoxides and CO₂ in one pot (Figure 5).(18) The catalytic system involved the zinc species in Figure 3, known to be active in ROCOP to form polycarbonates.(8) Williams’ group showed that this catalyst is inactive for the ROP of lactones to form polyesters, unless an epoxide is added as an initiator, which converts the zinc carboxylate into an active zinc alkoxide. The truly magical discovery was that the ROP reaction could be turned off again by adding CO₂. By adding or removing CO₂, ROCOP and ROP can be alternated, resulting in an unprecedented one-pot formation of copoly(ester-carbonates) (Figure 5). Figure 5. Chemoselective polymerization control.(18) If the bimetallic Zn catalyst (Figure 3) is mixed with caprolactone, no reaction takes place. Addition of epoxide activates ROP. If CO₂ is added, ROP is suppressed but ROCOP is activated. Removal of CO₂ reactivates ROP (green: active; red: inactive). Subsequently, Williams reported that anhydrides also could be used as a monomer feedstock in the chemoselective polymerization approach, and thus a large variety of copolymers can be formed in a highly selective manner.(19) In recent years, Prof. Williams has extended the portfolio of catalysts and (sustainable) monomers that can be employed and, in particular, has shown the controlled production of many new polymers with highly promising properties.(20) The use of CO₂ as a nonfossil carbon feedstock remains a major focus in her work. This is a topic that is gaining increased attention, as highlighted in the Organometallics special issue on CO₂ utilization, where Williams reported the isolation of a rare anionic Ti(IV) complex, assumed to be a model of the catalytic alkoxide intermediate.(21) Recently, her group showed how the combination of metals, chosen on the basis of their role in the catalytic cycle, can improve heterodinuclear catalysts for CO₂/epoxide copolymerization: in a reported Mg/Co complex, the magnesium center improves epoxide coordination and the cobalt center accelerates carbonate attack.(20f) It is particularly impressive to me when academics become innovators and company founders: in 2011, Williams founded Econic Technologies, a company focusing on catalysts to make polymers from CO₂. She commented in an interview: “Our first major catalyst discovery was in 2008. We filed a patent and continued to develop the science while exploring options for the technology and eventually formed Econic in 2011.”(22) For her industrial entrepreneurship, Prof. Williams was awarded the WISE Tech Start-up Award in 2015.(23) The catalysts developed by Econic are sold to polyol producers whose carbon dioxide based polyols then are used to make polyurethanes for applications: for example, soft foams for household goods, automotive components, adhesives, elastomers, and home insulation foams. In 2016, Williams became Professor of Inorganic Chemistry at Oxford University. The same year, she received the Corday-Morgan Prize, recognizing her contributions to using renewable resources to make polymers.(24) In 2018, she received the Otto Roelen Medal by Dechema and the German Catalysis Society, in recognition of her developments of highly active catalysts for CO₂ copolymerization.(25) There is no doubt that Williams has contributed fundamental breakthroughs in the field of homogeneous polymer catalysis and CO₂ utilization, and she is also a role model as an inventor and entrepreneur. Her impressive scientific record counts around 140 publications and 30 patents, many licensed industrially. In addition to her scientific achievements, she is a dedicated group leader and has mentored numerous postdocs, Ph.D. students, and undergraduates. Of her former group members, 16 are in academic positions worldwide. Besides chemistry, she has a love for the wilderness and for fossil hunting, alongside other hobbies, including swimming, cycling, and hiking. With her family she regularly goes on biking adventures and crossed Scotland by bike in 2019. To me, Prof. Williams is both a scientific and a personal role model. I have never worked with her, but just reading her publications has inspired me many times. I am a female chemist, and although I have performed research in academia for 20 years, my sense of belonging is small, which appears common for women in STEM fields.(26) Over the years, I have monitored my feeling of belonging and I have realized what makes it spike: inspiring female chemists, whose work and achievements remind me that women have a natural place in science and in academia. On days where the feeling of not belonging weighs particularly heavily on my shoulders, I look toward my role models, and it helps me calm my inner critic and carry on. Professor Charlotte Williams is such a role model to me and, I am sure, also to many others. Views expressed in this editorial are those of the author and not necessarily the views of the ACS. This article references 26 other publications.

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高分子魔术师：夏洛特·威廉姆斯教授

在有机金属，编辑团队一直在重点介绍一些我们认为对这一领域甚至对我们自己都有深远影响的科学家。在这篇社论中，我想介绍牛津大学的另一位先驱者和有影响力的人夏洛特·威廉姆斯教授。威廉姆斯教授致力于研究我喜欢的三件事：均相金属催化剂，二氧化碳和选择性。通过这些成分，她正在开发令人印象深刻的协议，以制造通用且可持续的聚合物。作为小分子化学家，我对着手制造聚合物的科学家敬畏。聚合物通常称为“塑料”，是由重复的亚基组成的大分子，并且具有较短的分子无法提供的良好性能，例如宏观韧性。目前，全世界范围内的聚合物产量为3.6亿吨/年。（1）然而，开发一种能够生产出具有理想物理化学性质的聚合物的聚合催化剂是魔术师的工作。正如威廉姆斯（Williams）和野崎（Nozaki）写道：与小分子催化剂相比，聚合催化剂还控制聚合速率，选择性和生产率，这些速率控制所得材料的结晶度，分解温度，粘度，流变性和机械性能。催化剂的选择也可用于调节聚合物的分子量，分散性，链组成，链结构以及区域和/或立体化学（2）夏洛特·威廉姆斯（Charlotte Williams）（图1）出生于1975年，曾在伦敦帝国理工学院学习化学，并于1998年在那获得了学士学位。研究（1998–2001），威廉姆斯与弗农·吉布森和尼古拉斯·朗合作，最初着手于经典的有机金属化学，重点研究二茂铁二烯配体。（3）实际上，威廉姆斯与他人合着的第一篇科学文章发表在有机金属中，标题为“ Hang与二茂铁一起滑行：1,1'-双（间苯二甲硫基）二茂铁的异常配位化学”（图2）。（3a）图1.夏洛特·威廉姆斯教授。图2.悬挂式滑翔机C，S-环金属化的Pt ^IV的X射线结构由1,1'-双（间苯二甲硫基）二茂铁（左）（3a）和悬挂式滑翔机（右）形成的配合物。（4）在Suzuki偶联和烯烃聚合催化下测试了二茂铁基复合物。（3c，e）由然后在聚合反应中使用均相催化剂成为Williams工作中的一个确定主题。在2001年至2002年期间，她是博士后研究员，首先与美国明尼苏达大学的William B. Tolman和Marc Hillmyer一起研究丙交酯开环聚合（ROP）。（5）随后，她从事有机金属发光聚合物的研究， （6）2003年，威廉姆斯回到帝国理工学院母校任讲师。在这里，她开始了自己的独立职业，致力于开发用于聚合反应的新型均相催化剂，由于威廉姆斯（Williams）对利用可持续原料开发聚合物的兴趣，₂作为潜在的聚合物成分进入了她的研究。然而，最初，她为开发高效的CO ₂共聚催化剂开发的所有尝试均以失败告终，经过数年没有成功的尝试，她的团队终于在2009年报告了一项重大突破（2008年获得专利）：一种还原型Robson型二锌催化剂能够使CO ₂和环己烯氧化物共聚的大环化合物（图3）。（8）Williams并不是第一个使CO ₂和环氧化物共聚的化合物。实际上，这种类型的第一个反应是由ZnEt ₂介导的，是由Inoue及其同事于1969年开发的。（9）随后的开创性研究导致达伦斯堡[10] Coates [11]和Lee [12]小组报告了定义明确的均相锌催化剂。 （13）然而，威廉姆斯的催化剂由于其性能而向前迈出了显着的一步：坚固，空气稳定，具有高端基保真度，最重要的是，首个定义明确的锌催化剂具有很高的活性。仅1 atm的CO ₂压力。（8）图3.（顶部）CO _2的共聚和环己烯氧化物（CAT =催化剂）。（下）Williams在2009年报道了双金属Zn催化剂（左）（8），在2010年报道了共模拟物的X射线结构（右）。（14）Williams研究小组在2010年报道了双金属钴类似物（图3）。 （右），它比锌催化剂具有更高的活性和选择性，不会产生环状碳酸酯作为不良副产物。（14）随后是第一款均质的异双核Zn / Mg催化剂，具有改善的CO ₂性能。-环氧共聚，但仍具有还原的Robson配体。（15）如果将Williams的最初工作描述为涉及悬挂滑翔剂复合物的合成（图2），那么我建议将这些美丽的大环催化剂用作她的后续射流。飞机（图3）。催化剂的优异性能可能归因于两种金属的接近，因为预期聚合物链的增长将通过涉及两个金属中心的穿梭机理发生（图4）。（15）图4.建议的双金属双环穿梭机理环己烯氧化物和CO _2的开环共聚（ROCOP）（基于参考文献（15）中所示的机理）。2009年，威廉姆斯成为帝国理工学院的读者，可以被视为等同于副教授。2011年，她获得了生物环境聚合物协会因其工作而获得的杰出青年科学家奖（16），并于2012年成为帝国大学的催化和聚合物化学教授。（17）威廉姆斯教授继续发挥聚合物魔术的作用，并于2014年报告了一种新颖的控制机制，该机制可实现在内酯的ROP与环氧化物和CO ₂的开环共聚（ROCOP）之间切换单个催化剂在一个锅中（图5）。（18）催化系统涉及图3中的锌物质，已知在ROCOP中有活性以形成聚碳酸酯。（8）Williams的研究小组表明，该催化剂对内酯的ROP没有活性除非添加环氧化物作为引发剂，否则它会形成聚酯，将羧酸锌转化为活性烷氧基锌。真正神奇的发现是，通过添加CO ₂可以再次关闭ROP反应。通过添加或除去CO ₂，ROCOP和ROP可以交替出现，从而导致空前的一锅形成共聚（酯-碳酸酯）（图5）。图5.化学选择性聚合控制。（18）如果将双金属Zn催化剂（图3）与己内酯混合，则不会发生反应。环氧化合物的加入会激活ROP。如果CO ₂添加后，ROP被抑制，但ROCOP被激活。去除CO _2会重新激活ROP（绿色：活动；红色：无效）。随后，威廉姆斯报告说，酸酐也可以在化学选择性聚合方法中用作单体原料，因此可以以高度选择性的方式形成各种共聚物。（19）近年来，威廉姆斯教授扩大了产品组合可以使用的催化剂和（可持续）单体的数量，特别是已显示出许多具有高度希望的性能的新型聚合物的受控生产。（20）将CO ₂用作非化石碳原料仍然是她工作的主要重点。正如在有关CO的有机金属专刊中所强调的那样，这一主题正受到越来越多的关注。₂利用，威廉姆斯报道了一种稀有的阴离子Ti（IV）配合物的分离，被认为是催化醇盐中间体的模型。（21）最近，她的小组展示了如何根据其作用选择金属的组合在催化循环中，可以改善CO ₂ /环氧化物共聚的异二核催化剂：在已报道的Mg / Co络合物中，镁中心改善了环氧化物的配位作用，钴中心加速了碳酸盐的进攻。（20f）当学者成为研究人员时，这对我尤其印象深刻创新者和公司创始人：2011年，威廉姆斯创立了Econic Technologies，该公司专注于由CO ₂制备聚合物的催化剂。她在一次采访中说：我们的第一个主要催化剂发现是在2008年。我们申请了专利，并在探索技术选择的同时继续发展科学，并最终在2011年成立了Econic。”（22）威廉姆斯教授因其工业企业家精神而被授予WISE科技启动2015年获得up-up奖（23）。Econic开发的催化剂出售给多元醇生产商，后者的二氧化碳基多元醇随后被用于制造聚氨酯，用于各种用途：例如，家用泡沫，汽车部件，粘合剂，弹性体和家用保温泡沫。2016年，威廉姆斯成为牛津大学无机化学教授。同年，她获得了科迪摩根奖认识到她在利用可再生资源制造聚合物方面的贡献。（24）在2018年，她获得了Dechema和德国催化学会颁发的Otto Roelen奖章，以表彰她在CO ₂共聚高活性催化剂方面的发展。（25）毫无疑问，威廉姆斯在均相聚合物催化和CO ₂领域贡献了根本性的突破她也是发明家和企业家的榜样。她令人印象深刻的科学记录涉及约140种出版物和30项专利，其中许多是工业许可的。除了她的科学成就之外，她还是一位敬业的小组负责人，并曾指导过许多博士后。学生和大学生。在她以前的小组成员中，有16个在世界范围内担任学术职务。除了化学外，她还热爱野外和化石狩猎，并热爱游泳，骑自行车和远足等其他爱好。她和她的家人经常骑自行车冒险，并于2019年骑自行车穿越苏格兰。对我来说，威廉姆斯教授既是科学典范也是个人榜样。我从来没有和她一起工作过，但是阅读她的出版物给我带来了很多启发。我是女化学家，尽管我在学术界进行了20年的研究，但我的归属感却很小，这在STEM领域的女性中似乎很普遍。（26）多年来，我一直监控着自己的归属感，并且意识到使它变得尖锐的原因：鼓舞人心的女化学家，他们的工作和成就使我想起，女性在科学和学术界具有天然的地位。在那些不属于自己的感觉特别沉重的日子里，我仰望自己的榜样，这有助于我平息内心的批评家并继续前进。夏洛特·威廉姆斯（Charlotte Williams）教授对我来说是一个榜样，而且我敢肯定，对许多其他人来说，也是这样。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。这对于STEM领域的女性来说似乎很普遍。（26）多年来，我一直监视着自己的归属感，并意识到使这种归属感飙升的原因：鼓舞女性化学家，他们的工作和成就使我意识到女性在科学中占有自然地位在学术界。在那些不属于自己的感觉特别沉重的日子里，我仰望自己的榜样，这有助于我平息内心的批评家并继续前进。夏洛特·威廉姆斯（Charlotte Williams）教授对我来说是一个榜样，而且我敢肯定，对许多其他人来说，也是这样。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26种出版物。这对于STEM领域的女性来说似乎很普遍。（26）多年来，我一直监视着自己的归属感，并意识到使这种归属感飙升的原因：鼓舞女性化学家，他们的工作和成就使我意识到女性在科学中具有天然的地位在学术界。在那些不属于自己的感觉特别沉重的日子里，我仰望自己的榜样，这有助于我平息内心的批评家并继续前进。夏洛特·威廉姆斯（Charlotte Williams）教授对我来说是一个榜样，而且我敢肯定，对许多其他人来说，也是这样。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。她的工作和成就使我想起，妇女在科学和学术界具有天然的地位。在那些不属于自己的感觉特别沉重的日子里，我仰望自己的榜样，这有助于我平息内心的批评并继续前进。夏洛特·威廉姆斯（Charlotte Williams）教授对我来说是一个榜样，而且我敢肯定，对许多其他人来说，也是这样。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。她的工作和成就使我想起，妇女在科学和学术界具有天然的地位。在那些不属于自己的感觉特别沉重的日子里，我仰望自己的榜样，这有助于我平息内心的批评并继续前进。夏洛特·威廉姆斯（Charlotte Williams）教授对我来说是一个榜样，而且我敢肯定，对许多其他人来说，也是这样。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文引用了其他26个出版物。