Authors: Stephanie R. Hare | Allan R. Pinhas | Julia Rehbein | Dean J. Tantillo | Stephen Wiggins
Source: Journal of Physical Organic Chemistry (article, 2022-09-08)
Field: Chemistry — Physical and Theoretical Chemistry

Barry Carpenter—Pioneering physical organic chemist, teacher, mentor, and friend This special issue of the Journal of Physical Organic Chemistry is dedicated to an outstanding physical organic chemist, mentor, and friend, Barry Carpenter, on the occasion of his official retirement. Knowing that great minds like his never fully retire, we thought a fitting tribute would be a compilation of recent research by people who have been lucky enough to have crossed paths—trajectories—with him. Here, you will find a selection of contributions from Barry's science family. We hope that the diversity of these contributions will encourage readers to broaden their views on reactivity and to delve deeper into its origins—as Barry's many contributions, in papers, talks, and personal discussions, have done. To Barry, we say thank you for having opened doors in our minds, for leading us beyond the well-trodden minimum energy path and into new adventures of chemistry. Below, we include (1) an autobiographical sketch provided by Barry himself, (2) testimonials from colleagues and friends speaking to Barry's contributions both professional and personal, and (3) a comprehensive list of Barry's publications. I was born in Hastings, in SE England, and lived there until 1967, when I left to go to college. As a child, I had become interested in chemistry and biochemistry after discussions with my older brother, who was the first in my family to pursue higher education, and who had studied biochemistry. My interest was further piqued by being given a chemistry set as a gift. It contained substances, such as sodium dichromate, that would never be permitted to be sold to children today. Even more remarkably, it was perfectly acceptable for a 12-year-old to go to the local pharmacy with a glass-stoppered bottle and have it filled with concentrated hydrochloric or even nitric acid! I am probably lucky not to have killed myself in my garden-shed laboratory. On the other hand, I am not sure whether the tepid items that pass for chemistry sets these days would have stimulated me to pursue chemistry as a career. My higher education began at the University of Warwick, which had only opened 2 years before my arrival. It had a real pioneering spirit, although was also clearly still a work in progress. Rather than having hallowed, ivy-covered buildings of centuries' duration, it consisted of blocks of white-tiled structures, causing some wits to liken it to a giant public toilet! The principal hazard of being a student there at the time was avoiding the tiles that would fall off the buildings with some regularity. In line with the general Zeitgeist of the late 1960s, there was a general wish to try new directions in education at Warwick. Germaine Greer was a lecturer in the English department at the time, for example. In the sciences, there was a similar wish to explore new ideas. So my degree course was actually in Molecular Sciences, rather than chemistry. Instead of teaching chemistry in a conventional fashion with what one might call the traditional, vertical divisions of organic, inorganic, and physical chemistry, there was an effort to take a topic, say stereochemistry, and to explore its meaning and importance across the traditional disciplines. Thus, the general field of chemistry was divided horizontally rather than vertically. I believe my exposure to this way of thinking influenced by own rather generalist tendencies later in life. I had originally thought that I would follow my brother's path and pursue biochemistry, but at Warwick I was inspired by one particular lecturer, John M. Brown, who showed me the delightful logic of physical organic chemistry. I decided that that was what I really wanted to do, and so pursued a doctorate in the topic with Prof. H. M. R. Hoffmann at University College London. I worked on the chemistry of “oxyallyl” cations (the class of reactive intermediate formally formed by breaking the 2,3 C–C bond of a cyclopropanone). I also dabbled in a bit of organometallic chemistry, exploring the question of whether the newly developed Woodward-Hoffmann rules applied to organometallic as well as organic reactions. Following my receipt of a Ph.D. in 1973, I headed off to the USA for postdoctoral studies. I applied to several of the big-name American physical organic chemists of the time, but was accepted by only one of them—Jerome Berson at Yale University. As it turned out, this was a very fortunate outcome, because I received the best possible education in Berson's lab. I felt at the time, and still believe today, that I learned more in the 18 months with Berson than the 6 years of chemistry education that I had had to that point. Berson was an outstanding mentor. He was not prescriptive about what one should study, but was absolutely rigorous about how one should study it. His outstanding intellect combined, I must say, with his qualities as just a thoroughly decent human being, had a very strong impact on me. With hindsight, it is no surprise at all that many of his students and postdocs went on to become outstanding independent researchers—sometimes in fields far removed from traditional physical organic chemistry. I had developed an interest in computational chemistry during my PhD and that interest grew during my time with Berson. However, doing computer calculations of any kind was a bit different then from the way it is today. I had to carry heavy boxes of punched cards across the street to the Yale computing center (and heaven forbid that one should slip on an icy path in the wintertime and drop the box!). The cards were left there and after, typically, a couple of days one could pick them up again, along with the output of the calculations on massive, folded sheets of paper. This exercise did not encourage one to try much in the way of exploratory calculation! As the time for my postdoctoral study drew to a close, the question arose about what I would do next. I had hoped to return to a position as lecturer in the UK, but in the mid 1970s, the UK economy was in recession and there were essentially no positions available. I consequently looked for places in the US and was lucky enough to land an Assistant Professor job at Cornell University. After just a few months at Cornell, it became clear to me that this was what I should have been doing all along. The Department was very welcoming and there were strong social as well as scientific interactions among the faculty members. I subsequently discovered that this was far from the norm among US academic departments, and so, just as I had done when I happened to land in Berson's lab, I had fallen into something of a bed of roses by nothing but blind luck. The fact that I spent 31 years on the faculty at Cornell says everything necessary about how I felt about the place. When I finally left in 2006, it was certainly not because I had developed any antipathy to the Department or to my friends and colleagues there. It was that Cardiff University, back in the UK, had created a new Physical Organic Chemistry Centre, and was looking for a director. They offered me the position, and I accepted it. That is where I finished my career, and Wales is where I still live. Over the many years of my career, I have been blessed to work with a large number of highly talented graduate students and postdocs. They have taught me at least as much as I taught them, and so I take this opportunity to express my sincere gratitude for the many ways in which they enriched my life. I may never understand why Barry offered a postdoc to a computational inorganic chemist with no synthetic organic experience. Nevertheless, I have always appreciated how the opportunity altered my chemical thinking—arrow pushing inorganic chemists are a rarity after all! The experience and humility gained from working with Barry and my labmates over just 2 years in Ithaca made a huge impact on how I have approached research problems and student mentoring. I am grateful for Barry's guidance, patience, and generosity. Happy retirement, Barry! After taking one of Barry's graduate courses, I really wanted to see what he was like when teaching an undergraduate organic chemistry course. One day, I had the privilege of witnessing him lecture to largely 2nd year Cornell University undergraduates. During the lecture, he asked the auditorium full of students a question. I sat there wondering; I could not imagine how this would unfold. Seared into my memory was Barry waiting, very patiently waiting quite some time for a student to respond. Of course a student responded, but to me the real story was the sheer magnitude of his gentle patience for his students. Barry's persistent patience was witnessed during every single Carpenter research group meeting; he modeled for all of his students, whether they were his graduate students or undergraduates, that persistence and patience were key to teaching and learning. From the beginning of graduate school, I considered Barry's papers essential reference material for physical organic chemistry (reference material that reads like poetry). It would not be hyperbolic to say that the vast majority of my understanding of kinetic rate theories and non-statistical dynamic effects came directly from his papers. Considering the applicability of his work to my own, it felt completely natural to pursue a postdoc position in his group. Though moving to a new country (US → UK) was a big life decision, with the Chemistry and Mathematics in Phase Space (CHAMPS) program starting right before I was planning to apply for postdoc positions, and considering the impact I knew his mentoring would have on my career, working for Barry was a pretty easy choice to make. Working on our first paper together taught me everything I needed to know about writing research papers: push past uncertainty to get words on the page, prioritize scientific rigor and clarity above all else, and do not be precious about keeping writing or figures on which you have spent a lot of time. That last lesson was a huge obstacle for me to overcome, but Barry helped me realize that scientific writing is for others and not yourself, and thus, you have to listen if the reader has critiques of how information is coming across. When I made my unceremonious departure from the UK in September of 2020, due to the COVID-19 pandemic, I never got the chance to say goodbye to Barry in person. I am so thankful for everything Barry has done to contribute to training, teaching, and advancing not just my career, but the physical organic chemistry community as a whole – a community that feels like a sprawling scientific family. Happy retirement Barry! Barry Carpenter has influenced me throughout his career. His early papers with his then-student Cindy Burrows on the effect of cyano substituents (at all five positions!) on the rate of the Claisen rearrangement interested me immensely (C. Burrows and Carpenter, papers contained and of physical organic chemistry, done in his early at years and I studied cyano group effects on the inspired by the I had many to Barry after that at to from and to from his of Organic which I for teaching, I immensely his and delightful I and his into a new for physical organic After he that field and showed the about that were many of and to a him into this a of other computational organic chemists have him to study and non-statistical views of how His to Cardiff years was a to but Barry to the chemical community with his into how It that Barry's contributions to science be as so and that you might be into that you could have at the if you had just thought about the and would not of course. certainly that his have been also his as a and that these so During my time in his research Barry's to teaching and his as a has had a impact on me as a chemist and as an me his writing or as and as they but rather his for the of and for the people with him in that He the in and every who is and Barry always showed the patience when to an undergraduate one of his graduate or a I him what could be as a question with the and patience that he would a even possible that I might have asked one of in my as an I do everything I every to my students with this Barry showed me how fortunate we are to not only be chemists but also to be to our with other chemists and students. I know been fortunate to have Barry some of and with me. It is my to my with Barry I first Barry when I his graduate physical organic class at Cornell, Chemistry course was the by Chemistry and I I am probably not the only student who thought that Barry's course should have that I was an undergraduate at the time, doing synthetic chemistry and planning a in that I still the first the and some that one not in an organic course. Barry of course had a – this was his to I also the first probably had a of about of this to because Barry was such an He made the material with his but just as Barry has an to The class was so that it made me fall in with organic chemistry and that as my career. Thus, I have Barry to thank for my I am so grateful to him for is also a to this graduate students were so by Barry's teaching that they the course to me I was an Chemistry was rather students about a but Barry was the kind of who one to to the such that the students the of both the class and One of graduate students later became my so I you could say that I have Barry to thank for my personal life as I first Barry in September of and became the first of his research group the in the or in a education of students has always been for He his students as and as Barry was to any I no how or how my research what were needed to understand the or to the Barry never me what to do, but he would what do you should be In he and his students, so they grew in this I went off in a different from what we Barry would about the and them with me. I have to my own with my students after Barry, and if I have been then it is a of my time in his research group. I would like to thank Barry for my as a and as a person. I became a of the Carpenter group in the fall of in the group him from where we all our as or I could not call him Barry and him Prof. me about Barry was his to problems in organic chemistry. His research problems were He was to organic chemistry what was to synthetic organic chemistry, a of The Barry his students was quite I wanted to take a course on with in my it into my research time, he He was with my to work with him and with I did not know that he He could have me on both but he me the to do what I the I could not group I work more and so I has a and the Carpenter group We had in the Carpenter group which was the of the He was one among us and with He asked for work Barry's were well thought and His were very clear and we sat One would not have any and his on the was very with as as one with It was only later that I that he must have spent planning courses, writing and and some of them were and Barry was also a great and One I one of the students on the and to the I was when the I was to was Barry, he just if this had happened to one of my students, I would have the student to work on a different to have a more Barry only looked at the effort in and me graduate at the of Barry's mentoring was one of the best that has happened in my When I was a postdoc at Cornell, I Barry's group in to of my postdoc I wanted to sure I had enough organic chemistry in my One of my from this time is Barry about non-statistical dynamic effects on organic I the words but I did not understand the back later in my independent I finally what non-statistical dynamic effects are and why they are and then that Barry knew all that He was so far of his such effects when organic reactivity is My time at Cornell to one paper with Barry, on of but I wish I had the to have the importance of dynamic effects back that time, I have had the of with Barry at and to know him a I his on science and was of his time with to the as I have always been at how he find in to scientific and them to in rather than When I my best papers I always Barry as a and my students that if we get this work past Barry, it must be I am grateful for the Barry has given me and the organic both directly and He is a giant and an My with Barry Carpenter had a We had essentially given up on understanding the of In with Barry, who was the department at the time, we the by this Barry came by the and the that was when Barry into the and that he knew what the is one of my from my time in This was the of a and with my group of physical with Barry the with the with and the of some years and many to our of organic Barry has always been and of our at even when they were or our he has very patiently taught my group how to Barry Carpenter was and still is a and mentor. 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