2020 Meeting of the Crystallographic Society of Japan

Volume 29, Number 1, 2021

ISSN 1067-0696

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Latest articles

Commentary

The decades-old mystery of bis(diethyl ether)tungsten(IV) chloride solved
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The decades-old mystery of bis(diethyl ether)tungsten(IV) chloride solved

André Schäfer

A hexacoordinated metal centre with an octahedral coordination environment is a very common motif in transition metal chemistry. This can involve neutral, as well as anionic, ligands or a combination of both. The latter can, inter alia, be found in many Group 6 complexes, often with donor solvent molecules acting as neutral ligands and saturating the coordination sphere of the metal(IV) centre. In particular, with regard to tungsten, many complexes of the type WX₄(solvent)₂ are known in the literature and are even found in textbooks nowadays, as, for instance, WCl₄(py)₂ (Brenčič et al., 1979) or WCl₄(MeCN)₂ (Manteghetti et al., 1999), which have even been structurally characterized by single-crystal X-ray diffraction. A common, yet ambiguous, example of this is bis(diethyl ether)tungsten(IV) chloride, WCl₄(Et₂O)₂. Although this compound has been `floating around' in the literature for many decades, surprisingly little analytical data concerning it have been reported, begging the question if it even truly exists.

Taking a look at the history of the compound, it starts in 1975 when Thiele et al. (1975) studied different benzyltungsten compounds, tetrabenzyltungsten amongst others, which they obtained from the reaction of dibenzylmagnesium with tungsten(IV) chloride bis(tetrahydrofuran), WCl₄(thf)₂. This, in turn, was synthesized from tungsten(VI) chloride, WCl₆, by treatment with diethylzinc in diethyl ether, whereas the authors proposed that the tungsten(IV) chloride bis(diethyl ether) adduct, WCl₄(Et₂O)₂, was formed initially, and was then transformed into the isolatable bis(tetrahydrofuran) adduct. Unfortunately, no analytical data for the bis(diethyl ether) complex was provided. At roughly the same time, Chisholm, Cotton and co-workers investigated the use of WCl₄(Et₂O)₂ as a possible precursor in the preparation of tungsten–tungsten triple-bond complexes (Chisholm et al., 1976a,b). While WCl₄(Et₂O)₂ was explicitly mentioned as a bis(diethyl etherate), it is worth pointing out that it was prepared in situ (by the same route as described above), with a 100% yield assumed, and was used without characterization. Therefore, although WCl₄(Et₂O)_x had already proven to be an interesting synthon, the exact nature and structure of the complex remained unclear and its composition, suggested to be a bis(diethyl ether) adduct, was based simply upon chemical intuition and the logical assumption of an octahedral complex with hexacoordinated tungsten (Fig. 1).

Figure 1: Tungsten tetrachloride bis(diethyl etherate), WCl₄(Et₂O)₂.

Almost a decade later, in 1985, Castellani & Gallazzi (1985) revisited the preparation of diethyl ether complexes of molybdenum and tungsten tetrachlorides, and made an attempt to characterize WCl₄(Et₂O)_x by elemental analysis to elucidate its exact composition. In contrast to previous articles, they reported that the mono(diethyl etherate), WCl₄(Et₂O), was obtained from diethyl ether solutions of WCl₆, which was based on elemental analysis suggesting not two but one equivalent of C₄H₁₀O [WCl₄(Et₂O)₂: C 20.3, H 4.3%; WCl₄(Et₂O): C 12.0, H 2.5%; reported by Castellani & Gallazzi (1985): C 11.5, H 2.4%]. First, it is worth mentioning that Castellani & Gallazzi seem to be the first to actually attempt to isolate the complex as a pure solid, rather than just synthesize and use it in situ. Furthermore, they reported that an orange reaction mixture, along with a yellow solid, formed initially, but that ultimately black crystalline needles were obtained and isolated. It seems odd that a compound could be obtained in the form of black crystals from an orange reaction mixture and, taking into account that a yellow precipitate was observed initially, this might point towards an equilibrium between a mono- and bis(diethyl etherate), due to the relatively weak complexation of the diethyl ether ligands. In fact, Castellani & Gallazzi pointed out correctly that other complexes, such as WCl₄(thf)₂ and WCl₄(py)₂, always feature two complexed solvent molecules.

It is puzzling that for decades this mystery remained unsolved, even though this complex was frequently used as a starting material in tungsten chemistry. Finally, in 2021, almost half a century after the complex first appeared in the literature, Jurca and co-workers were able to obtain a pure crystalline sample of the bis(diethyl ether) complex, WCl₄(Et₂O)₂, and conduct a complete structural characterization by single-crystal X-ray diffraction and NMR spectroscopy (Shaw et al., 2021). Different from previous reports, the authors used tungsten tetrachloride, WCl₄, as the starting material, dissolving it in diethyl ether. In a striking similarity to the report of Castellani & Gallazzi from 1985, they observed a yellow solution and were able to obtain not a black but a yellow crystal from it. Structural characterization of this crystal by X-ray diffraction confirmed it to be tungsten tetrachloride bis(diethyl etherate), WCl₄(Et₂O)₂, with trans-coordinated diethyl ether molecules in the axial positions (Fig. 1)! With this, the quest for the elucidation and structural characterization of the long-discussed WCl₄(Et₂O)₂ finally comes to an end, closing this gap in tungsten tetrachloride bis(solvent) complexes.

The question remains, did Castellani & Gallazzi actually obtain the mono(diethyl etherate), WCl₄(Et₂O), in 1985, as suggested? It seems not unlikely given the fact that diethyl ether is a rather weakly bonded ligand, and they reported black crystals instead of yellow ones and the elemental analysis was very much in line with a mono(diethyl etherate). Two interesting details are given by Jurca and co-workers here as well, namely, that `prolonged exposure to ambient conditions led to the appearance of dark spots on the crystal surface' and that `the compound is unstable under vacuum' (Shaw et al., 2021). This clearly suggests the loss of one equivalent of diethyl ether due to rather weak complexation, which would explain Castellani & Gallazzi's elemental analysis results.

Funding information

Funding for this work was provided by: Deutsche Forschungsgemeinschaft (grant No. SCHA1915/3-1).

References

Brenčič, J. V., Čeh, B. & Šegedin, P. (1979). Z. Anorg. Allg. Chem. 454, 181–186.

Castellani, L. & Gallazzi, M. C. (1985). Transition Met. Chem. 10, 194–195.

Chisholm, M. H., Cotton, F. A., Extine, M., Millar, M. & Stults, B. R. (1976a). J. Am. Chem. Soc. 98, 4486–4491.

Chisholm, M. H., Cotton, F. A., Extine, M. & Stults, B. R. (1976b). J. Am. Chem. Soc. 98, 4477–4485.

Manteghetti, A., Belin, C., Tillard-Charbonnel, M., Pascal, J., Clot, E. & Favier, F. (1999). New J. Chem. 23, 165–172.

Shaw, T. E., Sattelberger, A. P. & Jurca, T. (2021). Acta Cryst. C77. In the press.

Thiele, K., Russek, A., Opitz, R., Mohai, B. & Brüser, W. (1975). Z. Anorg. Allg. Chem. 412, 11–19.

This article was originally published in Acta Cryst. (2021). C77.

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Awards and prizes

2021 Ludo Frevel Crystallography Scholarship Awards
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Meeting report (IUCr supported)

4th International Symposium on Halogen Bonding
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4th International Symposium on Halogen Bonding

Catharine Esterhuysen

Oral presenters (from top left) Charles Loh, Martin Breugst, Pierangelo Metrangolo (moderator), Sebastian Hasenstab-Riedel, Marta Mosquera, Stefan Huber, Tatsuo Kaiho and Sekar Govindasamy discussing the theme of 'Applications in synthesis, catalysis and industry'. (Screenshot courtesy of Somananda Sanyal.)

The International Symposium on Halogen Bonding (ISXB-4) was held online from 2 to 5 November 2020 after being postponed from an event scheduled from 22 to 27 March 2020 in Stellenbosch, South Africa, owing to travel restrictions brought about by the COVID-19 pandemic. The ISXB-4 was the latest in the series of ISXB conferences initiated in 2014 by Giuseppe Resnati and Pierangelo Metrangolo. It focused primarily on halogen bonding, but incorporated all forms of σ- and π-hole type bonding, including hydrogen bonding. The symposium aimed to cover both experimental and theoretical aspects of a broad range of fields such as medicinal chemistry, chemical biology, materials science, catalysis, crystal engineering and industrial applications.

When the change to the online format for the conference was announced in July 2020 the response was overwhelmingly positive: where 88 delegates were due to attend the original on-site conference, 220 delegates from 29 different countries joined the online conference with great enthusiasm. This excellent turnout was aided by IUCr funding, thanks to which we were able to support the attendance of 30 young scientists, 13 (43%) of whom were female. The supported scientists represented 14 countries spread over 4 continents. As a result of their generous support, the IUCr was one of the sponsors with a virtual sponsor booth; these booths allowed delegates to get further information about the exhibitor and make contact with a company representative.

The many delegates were not disappointed: the scientific presentations were of an extremely high quality. A total of 25 invited speakers and 45 oral presenters gave live or pre-recorded talks in six sessions: the 'Nature of X-bonding' and 'Supramolecular chemistry and crystal engineering' on 3 November, 'Solid state properties' and 'Understanding X-bonding behaviour' on 4 November, and 'Applications in synthesis, catalysis and industry' and 'Applications in solution chemistry and biology' on 5 November. Within each session, all the oral presenters contributed to a live discussion on the theme, moderated by well-known members of the halogen-bond community. These discussions elicited enthusiastic participation from the audience through a question-and-answer chat function and resulted in some lively debates.

There were also 90 poster presenters divided between two poster sessions on 3 and 4 November. The standard was extremely high, but in the end, Vinu Panikkattu of Kansas State University, USA, was awarded the IUCr journals poster prize for his poster 'Exploring the strength and competition between chalcogen and halogen bonds through experiment and theory'.

Vinu Panikkattu presenting his prize-winning poster.

In addition to the scientific content, the social aspect of the conference was not forgotten: the welcome function included a session of "speed greeting" where delegates were randomly dealt into small groups so that they could greet old friends or get to know new members of the community. Delegates also had the opportunity to meet on an individual basis through the meeting hub, while every day ended with break-away "rooms" to give delegates the opportunity to get together and chat.

These social interactions combined with the live discussions meant that although delegates were sitting in front of computer screens spread over 17 time zones, they still felt a sense of community. ISXB-4 Virtual was, as a result, a resounding success. The organisers would like to thank the sponsors, particularly the IUCr, and all of the delegates for their role in achieving this.

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Feature article

Cryo-EM: expanding the reach of structural biology
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Cryo-EM: expanding the reach of structural biology

Catherine L. Lawson

Electron cryo-microscopy (cryo-EM) is rapidly becoming the method of choice to elucidate many important 3D structures in molecular and cellular biology, expanding the reach of structural biology well beyond materials that can be crystallized. I provide below a very brief summary of how we arrived at this point. The timeline described here follows in part a more extensive review that will shortly be published as part of a special collection celebrating the 50th anniversary of the Protein Data Bank (PDB) (Chiu et al., 2021).

EM scientists began investigating the overall shapes of biological materials in the mid-20th century. Early successes involved specimens with high internal symmetries – 2D periodicities, icosahedral viruses and helical assemblies. Symmetry enables averaging over many individual imaged subunits to obtain a final 3D reconstruction (density map). Experimental measurements typically include both electron diffraction (spots or layer lines) and direct images (for phasing). The 1982 Nobel Prize in Chemistry recognized the development of electron crystallography (Klug, 2010).

Minimizing radiation damage of biological materials on exposure to high-energy electrons was a major technological challenge. Early strategies involved low-dose exposure procedures and chemical embedding. Methods to vitrify and maintain specimens at cryogenic temperatures began to be developed in the mid-1970s, leading to substantial improvements in the collected data quality (Baker & Rubinstein, 2010).

The first 3DEM Gordon Research Conference was held in 1985 (see photo archived at https://www.ebi.ac.uk/pdbe/emdb/genealogy.html). The inaugural meeting, chaired by Wah Chiu, firmly established cryo-EM as a serious endeavor with a dedicated community of research scientists. The 3DEM GRC continues to play a critical role in sharing recent developments in the field. Meetings are held annually (outside of pandemics) with venues alternating between the US, Europe and Asia.

The 1990s and 2000s yielded many technological innovations, gradually increasing cryo-EM’s overall impact (Henderson, 2004). Microscopes with field electron gun sources became common in academic laboratories, yielding improved image signal-to-noise and spatial resolution. Keen interest in asymmetric (e.g. ribosomes) and lower-symmetry complexes (e.g. chaperonins) sparked the intensive development of single-particle reconstruction methods. Tomographic and sub-tomogram averaging methods were developed, enabling investigations of in situ materials in cellular and tissue samples such as muscle fibers. Software developers created packages that automated data collection, image classification and reconstruction. Some embraced electronic CCD detectors for their ability to automate data collection, but film still continued to be prized for its high sensitivity.

Crystallography and cryo-EM studies started to be combined in complementary ways. A common approach was to fit high-resolution crystal structures into low-resolution maps of large macromolecular complexes. Alternatively, low-resolution cryo-EM maps could provide critical phasing information for crystal-structure determination.

In this period, cryo-EM results were appearing with increasing regularity in the scientific literature. The community recognized a need to archive 3D reconstructions (density maps) and make them publicly accessible. The Electron Microscopy Data Bank (EMDB) was established in 2002 by Kim Henrick at the European Bioinformatics Institute (EBI) for this purpose. Soon after, and with input from many cryo-EM experts, Henrick and Helen Berman (Research Collaboratory for Structural Bioinformatics; RCSB PDB) spearheaded the development of a dictionary of data terms for cryo-EM experiments that could be utilized by both the EMDB and the PDB. In 2006, an NIH-funded international project was founded by Chiu, Henrick and Berman to provide a one-stop-shop for deposition and access to cryo-EM data and to serve as a community resource for news, events, software tools, data standards, challenges and validation methods [EMDataResource (Lawson et al., 2020)].

Seven years ago, cryo-EM had its famous “resolution revolution” (Kuhlbrandt, 2014). A key innovation was the introduction of new direct electron detectors with improved sensitivity and high speed, permitting the collection of movies. Post-imaging alignment of movie frames enabled researchers to overcome the previous limitations arising from specimen drift, yielding maps with much higher levels of structural detail (Fig. 1). Cryo-EM scientists have also learned how to computationally separate different classes of particles measured within the same set of images, yielding multiple reconstructions that can differ in composition and/or conformation. These innovations have substantially extended the reach of cryo-EM across a wide variety of specimens that are not readily crystallized (Fig. 2). The rapidly rising profile of cryo-EM in structural biology was internationally recognized by the 2017 Nobel Prize in Chemistry.

[Figure1] Figure 1. Shifting resolution profiles for cryo-EM maps archived in EMDB, plotted by map release year. The 2021 data are through 3 February. Source: https://www.emdataresource.org/statistics.html

Figure 2. Sampling of cryo-EM maps recently released in EMDB. Maps include several membrane-bound and soluble enzymes, a light-harvesting complex, a coronavirus spike glycoprotein and an icosahedral virus. Source: https://www.emdataresource.org/emdlist=released:2021

The recent pandemic has demonstrated the growing utility of cryo-EM. Important structural data about the circulating virus was produced very early on, with the first SARS-CoV-2 spike glycoprotein structure released on 26 February 2020 (Wrapp et al., 2020). A year later, more than 270 spike-containing map entries have been archived in the EMDB, representing the trimer, either alone or in complexes with antibody or receptor fragments. More than 60 maps are also available for other SARS-CoV-2 virus components such as polymerase and ribonucleoprotein.

In this rapid growth phase of cryo-EM, it is necessary to establish rigorous methods to validate the maps and associated models. EMDataResource promotes public awareness of this necessary step in structure determination, as is done in crystallography by sponsoring regular community Challenge activities and organizing and participating in community Task Forces (Lawson et al., 2020, 2021; Chiu et al., 2021).

References

Baker, L. A. & Rubinstein, J. L. (2010). Methods Enzymol. 481, 371–388.

Chiu, W., Schmid, M. F., Pintilie, G. & Lawson, C. L. (2021). J. Biol. Chem. In the press.

Henderson, R. (2004). Q. Rev. Biophys. 37, 3–13.

Klug, A. (2010). Annu. Rev. Biochem. 79, 1–35.

Kühlbrandt, W. (2014). Science, 343, 1443–1444.

Lawson, C. L., Berman, H. M. & Chiu, W. (2020). 'Evolving data standards for cryo-EM structures', Struct. Dyn. 7: 014701.

Lawson, C. L. A., Kryshtafovych, A., Adams, P. V., Afonine, M. L., Baker, B. A., Barad, P., Bond, T., Burnley, R., Cao, J., Cheng, G., Chojnowski, K., Cowtan, K. A., Dill, F., DiMaio, F., Farrell, J. S., Fraser, M. A., Herzik, S. W. Jr, Hoh, J., Hou, J., Hung, M., Igaev, M., Joseph, D., Kihara, D., Kumar, S., Mittal, B., Monastyrskyy, M., Olek, M., Palmer, A., Patwardhan, A., Perez, J., Pfab, J., Pintilie, J. S., Richardson, P. B., Rosenthal, D., Sarkar, D., Schäfer, M. F., Schmid, G. F., Schröder, M., Shekhar, D., Si, A., Singharoy, G., Terashi, G., Terwilliger, A., Vaiana, L., Wang, Z., Wang, Z., Wankowicz, C. J., Williams, M., Winn, T., Wu, X., Yu, K., Zhang, K., Berman, H. M. & Chiu, W. (2021). Nat. Methods, 18, 156–164.

Wrapp, D. N., Wang, N., Corbett, J. A., Goldsmith, C. L., Hsieh, O., Abiona, O., Graham, B. S. & McLellan, J. S. (2020). Science, 367, 1260–1263.

Catherine L. Lawson is at the EMDataResource Project, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, USA; cathy.lawson@rutgers.edu.

IUCr Journals have long championed the inclusion of research using techniques that complement crystallography, and recognised the spectacular growth in the adoption of cryo-EM by launching a new section of IUCrJ in 2016. Acta Cryst. D regularly publishes the proceedings of the Collaborative Computational Project for electron cryo-microscopy (CCP-EM) Spring Symposium, and together with Acta Cryst. F welcomes articles on cryo-EM as well as studies using other structural biology techniques.

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IUCr Congress

25th IUCr Congress and its background
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25th IUCr Congress and its background

Radomír Kužel

A pre-pandemic meeting of the local organisers of the 25th IUCr Congress at the Prague Congress Centre.

History

Czechoslovakia was accepted into the IUCr immediately after the first IUCr Congress in Boston, MA, USA, in 1948 as the fifth member together with USA, UK, Norway and Canada. The membership of the Czechoslovak National Committee in the IUCr was guaranteed originally by Charles University; later this was taken over by the Academy of Sciences and then the Czech and Slovak Crystallographic Association (CSCA) in 2017. A “meeting of crystallographers on special topics in structure analysis” was started by A. Kochanovská in 1954 at the headquarters of the Academy of Sciences and a long series of these traditional one-day seminars was established. Originally, the meetings, called “Discussions”, were organized under the head of the Institute of Technical Physics of the Academy of Sciences, later under the head of the Czechoslovak Society for Science and Technology and finally the CSCA. In 2016, the anniversary 300th Discussions Meeting on Recent Advances in Structure Analysis was organized in Prague.

The formal recognition of the Crystallographic Association – Krystalografická společnost as a stand-alone society was achieved on 6 February 1991. The logo of the association was designed by Z. Zikmund, and variations of it have been used as logos for different meetings including the 25th IUCr Congress. The Executive Committee, headed by the president and secretary, is responsible to the Scientific Board for all activities. All bodies and officers are now elected for a five-year period. See www.xray.cz for current officers and a full list of members of the Scientific Board.

A continuous series of Annual CSCA Conferences began in 1980. At these meetings, people interested in crystallography can meet for four days and discuss informally all scientific problems and directions of future activities of the CSCA. The conference is devoted to diffraction and non-diffraction techniques and methods for structural studies of compounds, applications of diffraction methods in practice, and the use of techniques in materials science, physics, chemistry and biology. The meetings are organized in different places in Bohemia and Moravia. Besides general and broad crystallographic topics, several focused meetings are organized. Recently, these have included Experimental methods in X-ray and neutron analysis, Computational methods, Small-angle scattering and Non-diffraction techniques for structural studies. Nowadays, the conference is named Struktura xxxx including the year. The usual participation at these annual meetings is 70–100 people.

A biennial student symposium is organized as part of the annual conference. The session contains student works – BSc, MSc and PhD theses in the field of crystallography, study of structures and microstructures mainly by X-ray and neutron techniques. Students from different universities in the Czech and Slovak Republics take part at this meeting. The presentations are evaluated by a wide committee and finally the best students are awarded.

In addition to general plenary lectures and other common contributions, sessions and highly specialized courses are usually organized in parallel for bio-crystallographers (course on protein crystallography – general, preparation of measurements and data collection, macromolecular structure refinement, precision and reliability) and people more directed to powder diffraction and materials science (course on the study of the real structure of materials, phase analysis). Courses on software are organized as well (structure databases, programs Jana, Maud, Mstruct, etc.). A course on the use of groups in crystallography was well attended, in particular.

IUCr2020

After several attempts, in 2014 we won the bid for the 25th IUCr Congress. We were looking forward to it and working hard for its preparation. We organized the workshop Current trends and future of crystallography in May 2019, connected with the meeting of the International Programme Committee. Both appeared to be very useful and we recommended such meetings also to future organizers of IUCr Congresses. Everything was going well till March 2020 when COVID-19 appeared. We found it was basically impossible to organize a classical congress in August 2020, and a quick virtual meeting of the IUCr Executive Committee unanimously decided to postpone the Congress to August 2021. This decision was accepted basically by all already registered people and companies with frequent comments that in 2021 people may be even more eager to attend the congress. However, at that time I was already thinking that we may only be postponing the problem.

Struktura 2020

Because we were organizing such a big congress in 2020, we did not plan to hold Struktura 2020. However, when the Congress was postponed we returned to it and decided to prepare Struktura 2020 for the end of November, when, we all hoped, the situation with COVID should have stabilized. Moreover, we did not expect a participation of over 100. The limit for indoor events was varying over time but in summer was as high as 500 so we did not expect problems. We agreed on the venue – a hotel in Tabor, a beautiful historical town about an hour's drive south of Prague – for two reasons. Struktura 2016 was held there, where we had a very good experience with the hotel and location, and the venue was also that planned for the largest pre-IUCr Congress workshop on electron crystallography.

Unfortunately, by the time we reached September, the pandemic was not decelerating but vice versa. At that time, it was decided to organize a hybrid congress from the hotel with the possibility for remote participants. We purchased better equipment such as cameras and sound systems and started preparation. We kept that idea till the beginning of November when it became clear that no real meeting would be allowed and possible and the only way was to prepare for a purely virtual conference. Before that point, we had already asked participants for their opinion. Most of them approved both real and virtual participation. Some of them said "No, I am only interested in a real meeting, not a virtual one“ and cancelled their participation. A few cancelled their lectures but approved their virtual passive participation. Others decided not to come to Tabor but were able to give a virtual lecture. In the end, we had about the same number of people as expected for a real conference (about 70).

We decided to host the virtual meeting on the Zoom platform as this was widely used and well known. We prepared a small TV-like studio center in one seminar room of Charles University, where a few presentations were given. The conference (25–27 November) had a few sessions as planned, for example on the use of synchrotron radiation, and it also included the first virtual student symposium and competition. In this competition, the main evaluation takes in a complex picture (scientific significance, contribution of the student, presentation quality, impression given by the speaker); however, just for interest, we evaluated the presentation skills of the speaker separately, i.e. how he/she is able to sell their work, almost regardless of the content. It was expected that in virtual form, these features would be suppressed. However, just the opposite was found, surprisingly. It seems that these skills are also important for virtual presentations. At the end of each day, the Zoom meeting remained open for 1–2 hours for free discussion.

So, our first virtual conference went very well, even though the participants expressed their hope to meet in person next time. The organization was quite easy and low cost. There were no technical problems. All the lectures were available from recordings in the Zoom cloud for registered participants for two months and then they were downloaded to our local storage media.

IUCr2021

In January 2021, we resumed communication with the IPC, keynote speakers, co-chairs and invited speakers in sessions to find out their plans.

The overall situation with COVID is very complicated. At the moment nobody knows anything definite about this summer. Currently, we cannot guarantee whether we will be allowed to organize the Congress in the Congress Centre or, if so, under which specific regulations. People don't know if they will be able to come. Therefore, we have started to prepare the Congress as primarily a virtual one but we would like to keep open the possibility of a real part till the last possible moment, i.e. we are retaining the idea of hybrid congress. The time when, I think, we can know more should be in June but not much earlier.

Up to now, we have received answers from about two thirds of the people mentioned above with the following statistics:

About 40% of people are still going to travel to Prague, if possible.

About 15% of people plan to do the same, but they see more problems.

About 15% of people would also like to come but think that it is not very likely.

About 25% cannot come but approved virtual participation.

Actually all the above approved virtual participation.

About 5% had to cancel their participation.

Hybrid system

Recently, we revisited the Prague Congress Centre, mainly to see their registration and presentation system for real/hybrid/virtual events and we were all quite happy with its flexibility. The local Czech company has been developing it for more than 10 years, has used it for even larger conferences than the IUCr Congress and during the last year, has focused on improving and extending the features for virtual or hybrid types of events and used it for such meetings. Over time, they have removed some things/features that had the potential to cause technical and/or quality problems. The system offers several types of virtual rooms (sessions, workshops, meetings) and a wide range of "poster" presentations, which can include videos, etc. Companies can have space on the website in the form of a 2D or 3D virtual booth, which allows the inclusion of descriptions, photos and videos and the possibility of multiple chats with individual customers. Every visit to the booth is recorded, with the list of visitors being sent to the exhibitor immediately after the event. Nothing anonymous is allowed.

Sessions

In principle, there is not much difference if the speakers or chairs are on-site or remote. The system does not require any installation of special software by the participants. Several browsers are supported. Two weeks before the lecture, registered participants can post questions in the lecture's Discussion window, which the speaker can answer there at any time. As a typical example, a participant can ask if some problem will be discussed in the lecture.

Individual speakers can communicate with technicians and must upload either a full pre-recorded presentation including sound (this could be useful, for instance, when there is a time difference; these types of presentations are now easy to prepare, e.g. in PowerPoint) or just a pure presentation. Everything can be tested.

A short time before the session all speakers and co-chairs of the session can communicate live in real time.

The session is streamed for remote participants. The presentations are always run from the local server in Prague. This is to avoid the possibility of a lower quality connection from the speaker. However, if the speaker is online, he/she has full control of the presentation. During the lecture any participant can type questions into the corresponding Chat window, which is visible by all participants (which helps to avoid duplicate questions). The moderator/co-chair selects questions from the Chat and asks the speaker in the discussion. This discussion is also recorded. No anonymous comments are possible.

Any remaining questions can be moved by the speaker from Chat to Discussion and answered any time later. Both Discussion and Chat windows are accessible all the time but the Chat window is only active during the session. The lectures can be made available for registered participants for two months without extra cost. Different kinds of "rooms" are possible. For workshops, the set-up is similar to Zoom. Anybody can share screens, all participants can be seen.

All the tools for a hybrid congress have been prepared. However, now we can only wait and hope for a successful vaccination program to suppress the spread of the virus.

Radomír Kužel is CSCA Secretary and IUCr25 Chair.

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Special report

Slovenian Chemical Society celebrates its 70th anniversary
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Slovenian Chemical Society celebrates its 70th anniversary

Albin Pintar

The Slovenian Chemical Society held an online ceremony on 15 February 2021 to celebrate its 70th anniversary.

In 2021, the Slovenian Chemical Society is celebrating the 70th anniversary of its existence. The beginning of the Society dates back to 1951, when Slovenian chemists decided to establish a professional association. The Slovenian Chemical Society was founded on 15 February 1951. The aims and objectives of the Society are set out in its statute, which states its mission to promote the advancement of chemistry, chemical technology and chemical engineering in the broadest sense, to take care about the growth of the expertise of its membership and to work with all organizations involved in the chemical profession, share experiences and provide help. Today, the Slovenian Chemical Society operates locally, nationally and globally in the spirit of the slogan "When chemistry is life".

The Slovenian Chemical Society has developed from a narrow group of experts and around 200 members into an organization that unites over 900 members. Throughout the period, a large number of eminent Slovenian chemists, scientists, professors from academic and research institutions, as well as experts from companies and public organizations worked in the society. It is thanks to them that the Society has been maintained all these years, also through many political and social changes that have always had an impact on the functioning of professional associations.

In order to ensure the progress of the profession, the Slovenian Chemical Society organizes lectures, seminars, congresses, symposia and summer schools, which have developed from local to internationally acclaimed events. The main annual event of the Slovenian Chemical Society is the scientific conference "Slovenian Chemical Days", which the association has traditionally organized as a conference with international participation since 1995. The conference is designed to contribute to the career development of young researchers. It should be emphasized that several members of the Society are also involved in obtaining and organizing international scientific events in Slovenia, with the great help of the Slovenian Convention Bureau.

Slovenian Chemical Days 2018.

As one of its main activities, the Slovenian Chemical Society has been publishing the scientific journal Acta Chimica Slovenica throughout its existence, in which domestic and foreign researchers and experts publish their works. Over the years, the journal has developed and gained an international reputation and an exemplary level of citation.

The Slovenian Chemical Society is also active in the field of international cooperation. Special mention should be made of the association's membership in IUPAC, EuChemS, IUCr, ECA, EFCE, EURACHEM, ECTN, EPF and EFCATS.

Although we like to look into the past, evaluate our work and reminisce, it is also important to look to the future, which, in the Slovenian Chemical Society, is full of planned paths, tasks and work enthusiasm.

There is a very active section for crystallography in the Slovenian Chemical Society, which has been headed by Anton Meden. Members of the section participate in activities promoted by the IUCr and ECA, and the main activities are focused on the organization of scientific meetings. Above all, it is worth mentioning the traditional crystallographic conference with international participation that has been organized together with the Croatian Crystallographic Society from Zagreb for almost 30 years.

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The IUCr Newsletter (ISSN 1067-0696; coden IUC-NEB) is published electronically by the International Union of Crystallography. Feature articles, meeting announcements and reports, information on research or other items of potential interest to crystallographers may be submitted to the Editors at any time. Items will be selected for publication on the basis of suitability, content, style, timeliness and appeal.

IUCr Newsletter

IUCr Newsletter

2020 Meeting of the Crystallographic Society of Japan

Latest articles

Commentary

The decades-old mystery of bis­­(di­ethyl ether)tungsten(IV) chloride solved

The decades-old mystery of bis­­(di­ethyl ether)tungsten(IV) chloride solved

Funding information

References

Awards and prizes

2021 Ludo Frevel Crystallography Scholarship Awards

2021 Ludo Frevel Crystallography Scholarship Awards

Meeting report (IUCr supported)

4th International Symposium on Halogen Bonding

4th International Symposium on Halogen Bonding

Feature article

Cryo-EM: expanding the reach of structural biology

Cryo-EM: expanding the reach of structural biology

References

IUCr Congress

25th IUCr Congress and its background

25th IUCr Congress and its background

History

IUCr2020

Struktura 2020

IUCr2021

Hybrid system

Sessions

Special report

Slovenian Chemical Society celebrates its 70th anniversary

Slovenian Chemical Society celebrates its 70th anniversary

Notice

CCDC 2021 User Group Meetings

CCDC 2021 User Group Meetings

Associates news

IUCr Associates: are you using your benefits?

IUCr Associates: are you using your benefits?

newsletter design: Michele Zema, Andrea Sharpe, Peter Strickland, Brian McMahon; newsletter logo design: Michele Zema

The decades-old mystery of bis(diethyl ether)tungsten(IV) chloride solved

The decades-old mystery of bis(diethyl ether)tungsten(IV) chloride solved