www.asiachem.news December 2021 | 99 EN: In the mid-1970s, there were essentially no computers in chemistry. We were still using Bunsen burner to heat things, fractional distillation, and crystallization, and all that we had was a 60 MHz NMR machine in our department. For that reason, people were so impressed by the CPK models and used them to solve chemistry problems. And Cram said that CPK models are the reality. My interest in modeling continued until the late 1980s, when we got a mainframe computer. Although that colossal machine was much slower than today’s iPhone, I immediately jumped into computational chemistry because I was eager to see events that happen in solution. I started collaborating with the late Prof. Keiji Morokuma in 1989, and that work eventually led me to transmission electron microscopy (TEM) in 2004. EK: This story leads me to the next question. You have traveled to many territories in science, including organic synthesis, nanoscience, organic electronics, organometallics, theoretical chemistry, EM, dynamic EM, to name a few. I find it quite unusual for a Japanese scientist who usually focuses on one area of interest for the entire career. What was your motivation to switch from one field to many others? EN: I have not switched the field. I have always stayed in physical organic chemistry but tried to explore new opportunities ahead of people. I’m not interested in synthetic chemistry by itself but getting the desired product in 100% yield suggests that you understand the mechanism pretty well. My main interest in mechanisms has taken me to all territories you’ve mentioned. In the 1970s, I was interested in molecular models, and after the 1990s, I went to computational chemistry. I started it in the late 1980s since Moore’s law predicted that we could study realistic systems in the mid-1990s. Similarly, when I started working on TEM around 2002, collaborating with Prof. Sumio Iijima, I hoped to study molecules at atomic resolution within 10 years. In 2015, we acquired a millisecond camera and the excellent resolution machine that we use now, and the camera was replaced by an even faster one in 2020. When I identify an opportunity, I tend to start preparing the background about five years ahead of others and wait for improved instrumentation and computer science. This way, as soon as the instrumentation and software become available, I can immediately do what I planned to do. EK: I understand that what I saw as diverse fields are different manifestations of the same general interest in mechanisms. There are two different types of scientists or two extremes of a continuous spectrum: those who try to understand and decipher the clockwork of Nature and those who take advantage of the available knowledge to make something valuable and practical. For example, those who study methodology and reaction mechanisms in synthetic organic chemistry look at basic phenomena. In contrast, those who practice total synthesis exploit the available knowledge to make molecules for various purposes. Where do you place yourself on that spectrum? Time may soon come that artificial intelligence tells us all what we need. Then we may need to accept it as the reality of chemistry in the years to come. EN: Well, youmay correctly put me in the first group because I am interested in fundamental research and mechanisms. However, I feel that I belong to both groups because I want to test mymechanistic hypothesis on something tangible like solar cells and iron catalysis. In line with the UNSustainable Development Goals (SDGs), we cannot rely forever on precious metals like palladium. In 2004 I coined the term “element strategy”, proposing a research initiative to the Japanese government. In the same year, I started our EM project. The generous funding of $15 million in our ERATO program led me to propose the teamwork of fundamental research and solar cells. We use functionalized carbon nanotubes as substrates to study chemical structures by TEM. But we also employ functionalized C60 for fabricating solar cells. Very recently, we have synthesized tiny blue quantum dots by self-organization approach. We did TEM video imaging at atomic resolution to precisely identify the whole structure of a single quantum dot. EK: I feel that your fundamental research is much more rewarding and fruitful, even when aiming at practical research goals. I see that your hypothesis-driven study can lead to valuable results, probably more effectively than a trial-and-error search. EN: Correct. Most achievements in the science of quantum dots resulted from the trial-and-error approach. Following empirical observations, people mixed various components making large and small dots with various ligands. That research has never been rational because they didn’t know the actual structure. We can change this practice by using our atomic resolution EM technology. EK: As for the empirical strategy, I remember attending a seminar by a famous Japanese chemist many years ago. He spoke about many successful palladium-catalyzed reactions. At the end of his lecture, I asked him about his efforts to explore the mechanism of the new reaction. He seemed puzzled when he looked at me, as if I was asking a silly question, and responded: “This reaction is very successful, and we get the product in nearly quantitative yield, so why should we waste time studying the mechanism?” EN: I am not surprised by this story, which can fit a significant number of Asian scientists. Asian scientists may continue to be more opportunistic and risk-taking. On the other hand, I feel that the 19th-century European value of “rationality” is dying out these days. Perhaps, we have already stepped into a “post-causality era”, as classical causal reasoning is not functioning anymore in this world of complexity. Time may soon come that artificial intelligence tells us all what we need. Then we may need to accept it as the reality of chemistry in the years to come.
RkJQdWJsaXNoZXIy NDU2MA==