A life in crystallography

Jorge L. Colón a, Angel Martí b and Luyi Sun c
aDepartment of Chemistry, University of Puerto Rico, USA. E-mail: jorge.colon10@upr.edu
bDepartment of Chemistry, Rice University, USA. E-mail: amarti@rice.edu
cDepartment of Chemical and Biomolecular Engineering, University of Connecticut, USA. E-mail: luyi.sun@uconn.edu

It is a great honor to act as guest editors for this themed issue in Dalton Transactions to honor Professor Abraham (Abe) Clearfield, who retired in spring 2019 from the Department of Chemistry at Texas A&M University after 43 years of service to the university. To honor Abe, we have invited a variety of distinguished researchers to present their latest research, reflecting the depth and diverse impact of Abe Clearfield in crystallography, inorganic solid-state chemistry, materials science, and inorganic chemistry for more than 60 years. Examples of topics in this issue include chemistry of nanosized layered inorganic compounds, the nanostructure and heterogeneity of materials, functional inorganic layered materials, layered organic–inorganic hybrid materials, novel layered copper–lithium phosphonates, bioinspired catalysts, inorganic solid-state chemistry, industrially significant catalysts and catalytic properties, multifunctional nanostructured materials, high performance functional materials for nanotechnology, biotechnology and micro/nano-electronics, and metal organic frameworks, among others.

Abe was born in Philadelphia, Pennsylvania to Ukrainian immigrants. He has been interested in Chemistry since he was 12 years old when his brother Ted bought him a Chemcraft chemistry set as a birthday gift. Although his high school chemistry course was very poor, this did not dissuade him from pursuing a chemistry degree. Nonetheless, even when he finished high school 12th in a class of 400, he did not receive a scholarship for college. It was his brother Ted, who was in the Navy, who came to the rescue; stationed in the South Pacific, he sent part of his salary to Abe every month. Together with money that Abe had saved from a variety of jobs in high school, it was enough to allow him to graduate from Temple University in Philadelphia with a B.A. But more importantly for Abe, during his time at Temple University he met Ruth, the love and soulmate of his life.

After obtaining his degree, the Chemistry Department at Temple University offered Abe a position to run the physical chemistry laboratory in their night school and earn an M.A. concurrently with free tuition and a monthly stipend. That monthly income allowed him to marry Ruth halfway through his M.A. studies. She was actually the one that convinced Abe to pursue a Ph.D. After obtaining his Master's degree in 1951, he was accepted into the Ph.D. program at Rutgers University. His entrance exam was so good that he was offered a fellowship with Phillip A. Vaughan, a former Ph.D. student of the great Linus Pauling at Caltech. This was the beginning of Abe's life in crystallography. For his 1954 Ph.D. thesis, Abe determined the X-ray crystal structure of zirconyl chloride, ZrOCl2·8H2O (published in Acta Crystallogr., 1956, 9, 555–558), at a time when there was no automated equipment and no computers. Zirconyl chloride was the compound that started Abe's journey in zirconium chemistry for the next 60 years. Abe was financially supported by a Meredith Fellowship from the titanium alloy manufacturing division of the National Lead Company. During those years, Abe was also present at the American Crystallography Association conference in 1953 where Hauptman and Karle presented their “direct methods” procedure for the determination of crystal structures.

Abe then spent a year with the Army Quartermaster Corp. in Natick, Massachusetts, after which he joined the Magnesium Electron Co. in Niagara Falls to work on solving the structures of semiconductor powders of interest to the company. Abe’s expertise was then required at the titanium alloy manufacturing division at the National Lead Company in Niagara Falls, New York, the largest supplier of zirconium chemicals in the world. Some years later, he started teaching a course in crystallography at the evening school at Niagara University. There were 15 students working in industry to whom he taught X-ray powder diffraction. One of the students was James A. Stynes, who obtained permission from the company to pursue a Master's degree at Niagara University with Abe as his research director. James and Abe successfully characterized the ion exchanger zirconium phosphate gel by converting it into crystals and establishing its composition as Zr(HPO4)2·H2O and its layered structure. Until then, zirconium phosphate was only available in the amorphous form. They published their results (J. Inorg. Nucl. Chem., 1964, 26, 117–129) and Abe decided to become an academic.

Abe started his journey as a professor at Ohio University in Athens, Ohio, where he established an X-ray lab, and taught a course in X-ray diffraction and crystallography with lab sessions on using the new X-ray equipment. His first two students were G. David Smith and Robert (Bob) H. Blessing. Dave solved the crystal structure of α-zirconium phosphate (Inorg. Chem., 1968, 8, 431–436), later refined in Abe's laboratory by Jan Marshall Troup (Inorg. Chem., 1977, 16, 3311–3314). Abe's lab was a pioneer in studying zirconium phosphate chemistry, and after Prof. Giulio Alberti at the University of Perugia discovered how to prepare zirconium phosphonates, both laboratories engaged in a very fruitful and friendly scientific rivalry in layered metal(IV) phosphates and phosphonates for the next 40 years that helped to establish and advance zirconium phosphate research.

The 1970s were marked by big changes in Abe's professional career. He was a program officer rotator at NSF during the 1974–1975 academic year. The late Dr Frank Albert Cotton convinced Arthur Martell to hire and bring Abe to Texas A&M University. Al had known Abe since their days at Temple University when Al was studying for his B.A. and Abe his M.A. Abe arrived at College Station, Texas in 1976 as a full professor. In his biography “My life in the golden age of chemistry: more fun than fun”, Al says that “Abe was one of the pioneers of the now fashionable field of materials science”. At Texas A&M, Abe built a major X-ray diffraction laboratory and helped bring Joe Reibenspies and later Nattamai Bhuvanesh to manage it. Years later Abe co-edited and co-authored with Joe and Nattamai a major book on X-ray powder diffraction (Principles and Applications of Powder Diffraction. Wiley-Blackwell: Chichester, 2008). Abe again pursued his interest in solving crystal structures from X-ray powder data and finally was successful, with his Ph.D. student Philip Rudolf (Acta Cryst., 1985, B41, 418–425) becoming one of the pioneers in solving structures using powder data, even holding at one time the world record for size: a 50-atom problem from powder diffraction data. They successfully unraveled the structures of the largest (at that time) zeolite pore structures, designated H1 and VPI-5. During those years, while Associate Dean for Research, Abe helped envision what later became the interdisciplinary Materials Science Program and eventually the Department of Materials Science & Engineering at Texas A&M University.

In the mid 1980s, one of us (Jorge Colón) was a graduate student at Texas A&M University when he met Abe. At that time, Jorge's Ph.D. mentor had told Abe that one of his graduate research students was perfect to be involved in a collaborative project between both laboratories to study the incorporation of luminescent molecules into zirconium phosphate layered compounds. They soon met and Jorge was impressed by this senior professor with a calm demeanor and serenity. He was then Associate Dean for Research of the College of Natural Sciences. Abe took a liking to Jorge and taught him about zirconium phosphate chemistry, but also about research administration in a major research university, and half of Jorge's Ph.D. dissertation ended up being the result of this collaboration. Jorge then took a postdoctoral position with Abe and while continuing working on zirconium phosphate derivatives, was introduced to layered double hydroxides and Keggin ions in Abe's lab. After Jorge returned to his native country of Puerto Rico, Abe and Ruth came to visit and gave a seminar at the University of Puerto Rico, Río Piedras Campus Chemistry Department. Later on, he visited the University of Puerto Rico again to participate in the Ph.D. thesis defense of now Prof. Angel Martí, Jorge’s first Ph.D. student and one of the guest editors of this themed issue. In the late 2000s, Jorge's research group started a project on using zirconium phosphate nanoparticles as drug carriers for anticancer drugs, and Abe and Jorge restarted their collaboration in this new field of zirconium phosphate chemistry. Several of Jorge's students visited Abe's lab for research stays that allowed them to quickly advance in their degrees and the collaboration was very productive. During the 2007–2008 academic year, Jorge spent a sabbatical year in Abe's lab and got to know Luyi Sun, a postdoctoral research associate with Abe from 2005 to 2006 who had advanced the studies of the intercalation chemistry mechanism of zirconium phosphate. Luyi was working in industry at that time, and later became an assistant professor at the Texas State University in 2009. Luyi is currently a professor at University of Connecticut, and is the third guest editor of this themed issue.

Abe and Jorge participated together in various symposia on layered materials, one of which was at the 2011 IUPAC World Chemistry Congress held in San Juan, Puerto Rico, at which a representative from Wiley was present. She approached them to suggest that they serve as editors of a book based on the symposium. The book, edited by Abe, Jorge and Ernesto Brunet, Professor at the Autonomous University of Madrid, Spain, who was also at the 2011 symposium, was published in 2015 and is titled Tailored Organic–Inorganic Materials.

Abe's service to the crystallography community is evidenced by his involvement with the American Crystallographic Association (ACA). He helped establish the ACA X-ray Powder Special Interest Group, which he chaired in 2004. He was also Chairman of the Synchrotron Radiation Special Interest Group in 1995–96, Secretary/Treasurer, U.S. National Committee for Crystallography in 1995–97, and Vice President (1998) and President (1999) of the ACA.

Abe has also won numerous awards, including ones for excellence in research for the Southwest (1995) and the Northeast (2008) regions of the American Chemical Society, and the Sigma Xi scientist of the year award in 2000, and obtained an honorary Ph.D. (honoris causa) from the University of Oviedo, Spain, in 1998. He was also given the title of Distinguished Professor at Texas A&M in 2007, a title given to the top tenured professors of the university. He was named a Royal Society of Chemistry Fellow in 2013. In spring 2018, the Professor Abraham Clearfield Materials Science Scholarship was established to honor his role in starting materials science and engineering education and research efforts at Texas A&M University. The scholarship supports outstanding undergraduate and graduate students pursuing a doctoral degree in the Department of Materials Science and Engineering. In 2019, the Texas A&M University Board of Regents named Abe Distinguished Professor Emeritus of Chemistry.

It is a great privilege for us to present this themed issue in honor of Abe Clearfield, which illustrates the excellent state of numerous areas of crystallography, solid-state chemistry, and materials science that he helped pioneer. We thank all our friends and colleagues who accepted our invitation to contribute to this themed issue. We are also grateful for the support of the Editorial Board of Dalton Transactions. We leave you with a quote from Abe from the 90th birthday symposium held in his honor in 2017 at Texas A&M University. “The search for knowledge and wisdom is eternal. Ultimately, it is the student's efforts who have made this journey a success”. We are grateful to have been Abe’s students and to be his friends.

This journal is © The Royal Society of Chemistry 2020