Editorial pubs.acs.org/cm
Cite This: Chem. Mater. 2018, 30, 5519−5520
The “Holey” Grail: Zeolites and Molecular Sieves Mark E. Davis and Raul F. Lobo, New Members of Chemistry of Materials’ 1k Club
Chem. Mater. 2018.30:5519-5520. Downloaded from pubs.acs.org by 5.62.154.46 on 08/28/18. For personal use only.
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materials that guided the synthesis of zeolites and molecular sieves as “templates.” In the manuscript, we argued that there may have only been one example of a true template (in the future, this case also turned out not to be true), and that a more appropriate denotation for these organic materials would be “organic structure-directing agents” (less specific host− guest interactions rather than true templating). Over the years since we published this paper, there have been a number of advances in the synthetic methodologies for preparing microporous materials and further understandings of the mechanisms of assembly. Needless to say, many details of the molecular-level assembly process still remain unknown. However, there are a number of aspects of the synthesis that can be influenced by the preparation method and composition; e.g., the pore size can be predicted from features of the organic structure-directing agent, the presence of what are called double four membered rings by the composition of the reaction mixture, etc. While several of the future synthetic objectives that we outlined have been achieved, e.g., pore systems involving intersecting 12 and 10 member rings, chirality, etc., there remain others, e.g., placing heteroatoms in specified crystallographic sites. CM: If you had to put your finger on it, what made your article special? What are you most happy about when you reread it? MED: I believe that the combination of the organized synthetic literature and the discussions on what was needed in future work provided the basis for the long-term referencing. For me, the final section of the manuscript titled “Rational “Design” of a Zeolite Synthesis” was the special feature of the paper. In that section, we described the concept of synthesizing chiral zeolites as an example of how one could perform certain elements of “design”. We discussed the issues of creating a chiral zeolite from both the point of view of the chiral inorganic framework and the organic structure-directing agent. As it turns out, those ideas were correct, it just took many years to fully understand how to correctly implement them. When we finally succeeded in synthesizing the first enantioenriched molecular sieve,5 the discussion we provided in 1992 was essentially correct. CM: What’s your advice to young scientists trying to discover the next breakthrough in material science? MED: (a) Do not be afraid to fail. Failure is a great teacher. I remind students that while they have had great successes in courses over the years, what they likely remember are the test problems that they got wrong. Those are the ones that make you think and learn the most. The same is true in research. The failures provide the stimulation to think harder and more carefully about the experimental plan and intermediate results. (b) Be patient. I tell the students in my research group “that it is difficult to be brilliant every week!” When you are working
s part of our continuing series of discussions with the authors of papers in Chemistry of Materials that have been cited more than 1000 times, we (CM) interviewed Prof. Mark E. Davis (MED) to talk about his 1992 review, “Zeolite and molecular sieve synthesis” (Figure 1).1 The review has been consistently cited since publication through today (35−60 citations/year, without exception), underlining the relevance of the authors’ perspective of the field, both of that time and into the future.2 The enduring strength of the review lies partly with its thoughtful synopsis of the history of zeolites and textbooklike, highly readable definition and description of zeolites, followed by a detailed review of synthetic approaches. The review focused on what was known about molecular assembly to template the formation of these porous materials, an area that still has many open and unanswered questions. The papers citing this 1992 review would also serve as a very helpful introduction for new researchers to the evolution and present state-of-the-art of the field of zeolite and molecular sieve synthesis. CM: At what stage of your academic career were you when you submitted this article to Chemistry of Materials? Who was the other author on the paper, and at what stage was he? Where is he now? MED: When “Zeolite and Molecular Sieve Synthesis” was written and published, I was a professor of chemical engineering at the California Institute of Technology.3 I had recently moved to Caltech after spending 10 years on the faculty in chemical engineering at Virginia Tech, and my coauthor, Raul Lobo, was one of the initial group of Caltech graduate students who joined my research program. Raul did a spectacular job of coauthoring the manuscript, as he was only beginning his Ph.D. studies. We not only summarized the field, but also provided insights for future work. The writing of this manuscript launched Raul into his very successful Ph.D. research. Raul is currently the Claire D. LeClaire Professor of Chemical and Biomolecular Engineering at the University of Delaware.4 CM: Given the high number of citations of this review, a significant amount of research has been impacted over the years. Where did you think the field was headed when you wrote the review? In your opinion, how has this particular research field evolved ever since? MED: When we wrote the review, we summarized the field of zeolite and molecular sieve synthesis by categorizing the various types of materials and focused on important mechanistic issues within each group. The idea was to concentrate on bringing forth known mechanisms and unknown trends in the assembly of microporous solids. Since we outlined issues of significance and presented ideas for future investigations, those topics have maintained relevance for some time. Also, the concept of rational design was being discussed at that time, as it is today, and we pointed out what was possible. For example, many papers referred to the organic © 2018 American Chemical Society
Published: August 28, 2018 5519
DOI: 10.1021/acs.chemmater.8b02658 Chem. Mater. 2018, 30, 5519−5520
Chemistry of Materials
Editorial
Figure 1. Figure from ref 1, connecting zeolite pore size with the diameter of various molecules. Reproduced with permission. Copyright 1992 American Chemical Society. Polycrystalline Molecular Sieves. Proc. Natl. Acad. Sci. U. S. A. 2017, 114, 5101.
on a significant problem, it is going to take time. Often, it can take years before you are even asking the right questions. Great problems do not come along every day, so you should not expect solutions every day. (c) Pay attention to details. In experimental investigations, small details that are often overlooked are the ones that lead the way to solutions. If something seems a bit strange, follow it up, as it is likely that you are missing something of importance until you understand its origin. (d) Take luck whenever you can get it, but do not count on it!
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Carlos Toro, Managing Editor Jillian M. Buriak, Editor-in-Chief AUTHOR INFORMATION
ORCID
Jillian M. Buriak: 0000-0002-9567-4328 Notes
Views expressed in this editorial are those of the authors and not necessarily the views of the ACS.
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REFERENCES
(1) Davis, M. E.; Lobo, R. F. Zeolite and Molecular Sieve Synthesis. Chem. Mater. 1992, 4, 756−768. (2) As of June 22, 2018, this review has 1024 citations in Web of Science, and 1471 citations in Google Scholar. (3) https://markdavisgroup.org. (4) https://sites.udel.edu/lobogroup/. (5) Brand, S. K.; Schmidt, J. E.; Deem, M. W.; Daeyaert, F.; Ma, Y.; Terasaki, O.; Orazov, M.; Davis, M. E. Enantiomerically Enriched, 5520
DOI: 10.1021/acs.chemmater.8b02658 Chem. Mater. 2018, 30, 5519−5520
