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Crystallography and Chemistry: an Ongoing Engagement Gautam R

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Crystallography and Chemistry: an Ongoing Engagement Gautam R Angewandte. Editorial DOI: 10.1002/anie.201308513 Crystallography and Chemistry: An Ongoing Engagement Gautam R. Desiraju* Crystallography is as old as chemistry therefore sufficient unto itself. It has no itself. As an intellectual endeavour, it is practical influence in a living context for practically without equal, such that its most precious products, crystalline however, crystallography was derided as Johann Wolfgang von Goethe, who was gems, first have to be cut and polished a “tool” of no research significance, and also interested in mineralogy, said al- before we can use them to adorn our organic chemists, mostly between 1960 womenfolk.” In contrast, his attitude to and 1990, would often ask rhetorically as chemistry is more generous as he states to the relevance of the structure of “The opposite can be said of chemistry, a molecule in the crystal in the context which can be applied in the most of its solution chemistry. Much of this extensive way and proves to be of the mercifully came to an end with the most unlimited influence on life.”[**] advent of organometallic chemistry The contrast between crystal statics and the appearance of a large number and chemical dynamics continues to of compounds whose complex internal pervade and persist in the consciousness molecular structures could not be deter- of chemists, even though crystallogra- mined in solution; notably NMR spec- phy and chemistry have merged in many troscopy was not an effective structure- most regretfully, if a little disparagingly contexts and are almost indistinguish- determining “tool” for this category of “Seen as a science, crystallography is an able today. compound. The crystal structure often altogether unusual case. It is not pro- was the only structure one had. Still, ductive; it is just itself, not giving rise to We have indeed traveled in the crystallographers were not intimidated anything else, more especially now that 200 years since Goethe, and especially by chemists altogether—Jack Dunitz a number of isomorphic bodies have so during the last century since the described the manner of structure de- been found which turn out to be quite discovery by Max von Laue of diffrac- termination by chemists and crystallog- distinct according to their content. As it tion by crystals and the development of raphers as trying to locate furniture in really is not possible to apply crystallog- methods to determine the internal struc- a darkened room. He claimed that raphy in any way, it has developed ture of matter. The ability to image the a chemist will find the furniture by largely as something self-contained. It structure of matter at an atomic and stumbling around in the darkness and gives the mind a certain limited satis- molecular level has had deep-seated bumping into each and every piece but faction and is so manifold in its detail consequences in chemistry and biology. that a crystallographer need just turn the that it can be called inexhaustible; which In the context of Angewandte Chemie,it lights on and see the arrangement at is the reason why it keeps a lasting and is pertinent to discuss the relationship once! decisive hold on outstanding people.” that crystallography has had with One is tempted to ask whether inex- chemistry. Lawrence Bragg was criti- Crystallographers and chemists have haustible detail can really exert an cized early in his career of trying to had more serious exchanges: 1) what is endless fascination over outstanding reduce chemistry to geometry. Linus the “real” structure of a molecule, real people. In any case, Goethe continues Pauling showed time and again, that at least in a chemical context; is it the to emphasize the introverted nature of chemical considerations could simplify “not so accurate” structure that is ob- the subject when he says “Crystallogra- the process of crystal structure determi- tained in an X-ray diffraction experi- phy has something of the monk and the nation. This was especially relevant in ment that shows electron density or the confirmed bachelor about it and it is his time, when the determination of “more accurate” structure that one crystal structures of “small molecules” obtains by neutron diffraction? was in itself a nontrivial task. In general 2) Which is the “more meaningful” [*] Prof. G. R. Desiraju molecular structure, the one obtained Solid State and Structural Chemistry Unit Indian Institute of Science [**] The original citations are from Maxims and with the most sophisticated X-ray dif- Bangalore 560 012 (India) Reflections, a collection of quotes that was fraction experiment, or the one obtained E-mail: [email protected] published posthumously in 1833. with the most sophisticated state-of-the- 604 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. Int. Ed. 2014, 53, 604 – 605 Angewandte Chemie art computation, if these structures are inate the fundamental role of crystallog- Pakistan, aims to bring together a similar different? 3) Can one establish direct raphy for the development of chemistry, group from China, India, and Pakistan connections between molecular struc- mineralogy, physics, biology, medicine, under the umbrella of chemical crystal- ture and crystal structure and therefore materials science, geosciences, and to lography and pharmaceutical sciences. predict crystal structures from molecu- emphasize role of the results from The third meeting is scheduled in lar structures? 4) How many crystal crystallographic research in everyday Bloemfontein, South Africa, as an ad- structures can a molecule have, or does life to students and scientists. To render junct to a workshop on powder diffrac- polymorphism have no upper limit if these lofty goals into practical execu- tion and hopes to bring together govern- one varies the crystallization conditions tion, many activities have been planned ment representatives from many coun- sufficiently, including computer simula- across the world, including this special tries in Sub-Saharan Africa and North tions? One can go on; distance-resolved issue of Angewandte Chemie. Africa. There is a real necessity for crystallography is now supplemented by scientists to think beyond political and time-resolved crystallography so that The opening ceremony of IYCr2014 other borders. Therefore these summits, crystallographers can enter the domains will be held at the UNESCO headquar- which will be attended by scientists in of dynamics—an area that they were ters in Paris on 20th and 21st January, academia and industry, and by science traditionally excluded from. Chemistry 2014. About 2000 participants are ex- administrators, are planned between today is an interplay of synthesis, struc- pected to attend, including ambassadors countries that have hitherto been divid- ture, and dynamics. Crystallography and representatives of governments of ed on the basis of geography, ethnicity, dominates structural chemistry, but it member countries to UNESCO, as well religion, or politics. The meetings will has also made significant inroads into as crystallographers from all over the focus on high-level science, also high- synthesis, as for example in crystal world and delegations from other inter- lighting the difficulties and problems of engineering, and into dynamics. One national scientific and educational soci- conducting competitive scientific re- cannot conceive of modern chemistry eties. The event will use science to bring search in different parts of the develop- without crystallography. nations together and ignite new collab- ing world. orations. The International Union of Crystallog- The IUCr has strong experience in raphy (IUCr) was founded in 1948 and The IUCr and UNESCO have drawn up conducting programs in developing re- today, 51 countries adhere to it, through an ambitious plan for open laboratories gions. The IUCr Initiative in Africa three Regional Associates (American, and summit meetings in Asia, Africa, dates back to 1999 and provides faculty Asian and European) and 41 National and South America in the context of and students with training in crystallog- Associates. The IUCr publishes very IYCr2014. These open labs are being raphy teaching and research methods. high quality crystallographic research planned with major equipment makers. Thanks to the collaboration with in eight journals, and a ninth one, called New installations of crystallographic UNESCO and The World Academy of simply IUCrJ, will be launched in 2014 instrumentation will be made in Ivory Science for the Advancement of Science to coincide with the International Year Coast and Uruguay to serve as research in Developing Countries (TWAS), the of Crystallography. The IUCr, as a de- hubs, hosting students and researchers IUCr will now extend the Initiative in pository of crystallographic standards, from neighboring countries. Otherwise, Africa into the open lab project and also also acts as an editor and publisher of these open labs will function where an target South America. Its aim is to make the International Tables of Crystallog- X-ray diffractometer is already opera- science more broad-based and energize raphy, thus facilitating standardization tional. Parallel to this initiative, some youth in parts of the world that have of methods, units, nomenclature, and workshops and tutorials will be held in remained underdeveloped for too long. symbols. Additionally, the IUCr pro- the factories of the diffractometer man- motes international cooperation in crys- ufacturer companies, thus also opening In changing times, there is a need for tallography and coordinates
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