bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-T magnetic anomaly in Ca2Fe2O5studied by single-crystal neutron diffraction
Authors: Auckett Josie , McIntyre Garry , Avdeev Maxim , De Bruyn Hank , Ling Chris
Published: November 2015

Ca2Fe2O5, which belongs to the Brownmillerite family of promising solid-oxide fuel cell membrane materials, is an antiferromagnet (AFM) below TN = 720 K. A small ferromagnetic (FM) canting perpendicular to the AFM easy axis has previously been established by physical properties measurements, but never observed crystallographically. More intriguingly, it has been known for some time to display an anomalous elevation in magnetic susceptibility for 60 K < T < 140 K. [1] Based on measurements performed with small oriented single crystals, Zhou et al. [2] proposed that this anomaly was due to a reorientation of the spins from the crystallographic a axis to the c axis below 40 K, with a region of minimal magnetocrystalline anisotropy in the anomalous temperature interval. In order to test this, we grew a very large (~1 cm3) single crystal by the floating-zone method and collected neutron Laue diffraction data, against which we refined both the atomic and magnetic structures of Ca2Fe2O5 between 10 K and 300 K. We designed and built an ad hoc sample mount to apply a small (~35 Oe) magnetic field to the sample, ensuring perfect consistency with the magnetic susceptibility data, which were collected in a comparably small field. Our refinements against both zero-field and in-field diffraction data reproduce the G-type AFM structure of Ca2Fe2O5 excellently at room temperature, including the FM canting which we have refined to statistical significance for the first time. We can also show that in the intermediate temperature interval (T = 100 K), the spins are slightly less well-ordered due to competing sublattice interactions. However, careful examination of the data reveals that the material is still best described by the room-temperature magnetic structure at all measured temperatures – i.e., the spin-reorientation hypothesis is incorrect.
Dispersed Lone Electron Pairs in Cubic Polymorph of Arsenic(III) Oxide
Authors: Gunka Piotr , Chen Yu-Sheng , Zachara Janusz
Published: November 2015

Stereoactive lone electron pairs (LEPs) situated on arsenic atomic cores in arsenic(III) compounds are responsible for a number of their interesting structural features. Thanks to their presence, arsenic may be involved in weak interactions such as As···O and As···X (X stands for halogen). It is the directional As···O interactions that cause the sphere-like As4O6molecules to pack in a diamondoid network in the cubic polymorph of As2O3, arsenolite, rather than in the closest-packed-sphere-type structure as P4O6molecules do in phosphorus(III) oxide. Recently, Gibbs and co-workers have determined the charge density distribution (CDD) in As2O3polymorphs by means of periodicab initiocalculations and have analysed its topological features.[1] Matsumoto et al. investigated the role of LEPs in As, Sb and Bi sesquioxides.[2] We have carried out a very precise high-angle diffraction experiments on arsenolite single crystals using both laboratory X-ray source and synchrotron X-ray radiation. The obtained diffraction data have been analysed utilising the Hansen-Coppens multipolar model and X-ray constrained wavefunction refinement. CDD resulting from both models has been analysed within the QTAIM (Quantum Theory of Atoms in Molecules) framework. The structural activity and localisation of LEPs has been compared with the predictions of bond valence vector model.[3] The computations performed by Gibbs et al. are critically evaluated by comparison with the experimental results extended by our own calculations in Gaussian basis sets. The obtained results suggest arsenic LEPs are dispersed into three distinct regions in arsenic atomic core vicinity.
Nanocrystalline diamond (NCD): an insight into structure-property relationships
Authors: Dubrovinskaia Natalia , Dubrovinsky Leonid , Solopova Natalia , Abakumov Artem , Snigirev Anatoly , Snigireva Irina , Prakapenka Vitali , Hanfland Michael
Published: November 2015

Nanocrystalline diamond (NCD) is a unique material we produce by direct conversion of glassy carbon into diamond at ca. 20 GPa and 2200 K in a multi anvil press. One of precursor materials we use is commercially available in the form of glassy carbon balls with a diameter of 20 to 50 microns. NCD demonstrates superior mechanical properties (e.g. extremely high yield strength under confining pressure) and has been successfully used for ultra-high static pressure generation (above 600 GPa) in a double-stage diamond anvil cell (DAC) (Ref. 1). To elucidate structure-property relationships in this extremely strong and seemingly inscrutable material we have investigated its microstructure using HRTEM and HAADF-STEM, measured its compressibility by means of synchrotron X-ray diffraction in a DAC, and evaluated its hardness in comparison to that of the hardest known materials - single-crystal diamond and nano-polycrystalline diamond (NPD) (Ref. 2). An additional insight into the volume compressibility was obtained due to X-ray phase contrast micro-imaging using a coherent high-energy synchrotron radiation. The established structure-property relationships will be presented and analyzed.
Improvement of SAXS Lab Equipment by Using Scatterless Apertures
Authors: Wiesmann Joerg , Kleine Andreas , Umland Christopher , Beerlink André , Graf Juergen , Michaelsen Carsten , Gollwitzer Christian , Krywka Christina , Kreith Josef
Published: November 2015

Parasitic scattering caused by apertures is a well-known problem in X-ray analytics, which forces users and manufacturers to adapt their experimental setup to this unwanted phenomenon. Increased measurement times due to lower photon fluxes, a lower resolution caused by an enlarged beam stop, a larger beam defining pinhole-to-sample distance due to the integration of an antiscatter guard and generally a lower signal-to-noise ratio leads to a loss in data quality. In this presentation we will explain how the lately developed scatterless pinholes called SCATEX overcome the aforementioned problems. SCATEX pinholes are either made of Germanium or of Tantalum and momentarily have a minimum diameter of 30µm. Thus, these novel apertures are applicable to a wide range of different applications and X-ray energies. We will show measurements which were performed either at home-lab small angle X-ray scattering (SAXS) systems such as the NANOSTAR of Bruker AXS or at synchrotron beamlines. At the PTB four-crystal monochromator beamline at BESSY II data was collected for a comparison of conventional pinholes, scatterless Germanium slit systems and SCATEX pinholes. At the Nanofocus Endstation P03 beamline at PETRA III we compared the performance of our SCATEX apertures with conventional Tungsten slit systems under high flux density conditions.
Spatio-temporal Structure of Filler in Rubber Studied with X-ray Scattering
Authors: Shinohara Yuya , Kishimoto Hiroyuki , Amemiya Yoshiyuki
Published: November 2015

Filler nanoparticles such as carbon black and silica play a vital role in the reinforcement effect of rubber, whereby its viscoelastic and mechanical properties are dramatically improved. The reinforcement effect is of great importance for developing rubber products such as vehicle tires. Its mechanism, however, has not been clarified despite a large number of studies. We have aimed at elucidating the mechanism by clarifying the spatio-temporal hierarchical structure of filler nanoparticles in rubber with various X-ray scattering techniques: ultra-small-angle X-ray scattering (USAXS) for elucidating the hierarchical structures of filler aggregates and their deformation under stretching, and X-ray photon correlation spectroscopy (XPCS) for observing the translational and rotational dynamics of nanoparticles in rubber. For that purpose, we have developed time-resolved two-dimensional USAXS at BL20XU [1] and XPCS at BL40XU, SPirng-8 [2, 3]. Based on the results of these novel scattering experiments, we have characterized spatio-temporal structure of filled rubber system, thereby developing tire products. In this presentation, experimental details and their results will be presented.
2014 - The international year of crystallography in Croatia
Authors: Višnjevac Aleksandar , Popović Stanko
Published: November 2015

"Croatian Crystallographic Association (under the auspices of Croatian Academy of Sciences and Arts - CASA) and Croatian Association of Crystallographers (CAC, a legal, non-profit entity), conduct numerous activities to celebrate the IYCr2014 in Croatia. International workshop ""Hot Topics in Contemporary Crystallography"" in Šibenik, held from 10th to 15th of May, 2014, gathered 27 young crystallographers and 6 speakers, the OC chair being A. Višnjevac. Scientific meeting ""Contemporary Crystallography in Croatia"", dealing with the present studies and perspectives, will be held in Zagreb, on September 30th, 2014, with the presentation of 20 papers and participation of more than 50 scientists. Proceedings of the Meeting will be printed and published. English-Croatian Dictionary of Crystallography, Solid State Physics and Materials Science, containing 1650 terms, will be published during 2014 by the Institute of the Croatian Language and Linguistics. The authors are S. Popović, A. Tonejc and M. Mihaljević. A review ""Hundred years of Crystallography"" in the journal Chemistry in Industry was published by B. Kojić-Prodić and K. Molčanov [1]. Another review, ""Chemical Crystallography before X-ray Diffraction"" was published by K. Molčanov and V. Stilinović [2]. The lecture ""IYCr2014 – one hundred years of exploring the world of atoms"" was presented by S. Popović before the CASA in Zagreb, on November 20th, 2013. ""Nikola Tesla, scientist and inventor, and the discovery of X-rays"" was the title of a lecture presented by S. Popović at the Meeting ""The Scientific and Technological Legacy of Nikola Tesla"" organized by the CASA in Zagreb, on December 17th, 2013. CAC is organizing a series of popular lectures on crystallography in professional societies and in secondary schools in Croatia. The newest project is the ""Crystal growing competition"" conducted by E. Meštrović. Finally, CAC is especially proud to organize the ECM29 in Rovinj, Croatia, in August 2015."
The International Year of Crystallography in the Americas
Authors: Teeter Martha
Published: November 2015

The American Crystallographic Association has focused its celebration of IYCr principally on outreach to spread the message of the importance of crystallography in our daily lives and to attract young people into science. We have formed an Ad Hoc Task Force, representing 13 geographical regions of 100-200 members each to develop our goals, to coordinate events and to enable specific activities. Key to our activities are a website which offers an attractive link for young scientists, projects and teaching tools for schools, biographies of important crystallographers, an adopt a crystallographer link, and video and crystal growing contests. We have continued to send scientists to Latin America for training workshops and assist Latin Americans in attending the ACA meetings. In order to create a lasting legacy for the International year, we have worked closely with national organizations such as in the US the National Science Teachers Association, the American Chemical Society, the American Institute of Physics, as well as student outreach groups like the Society for Physics Students. Forging an ongoing relationship with these organizations will aid our continuing outreach. Similar organizational contacts have been made in Canada and in Latin America. Working with national organizations can also help to influence the political climate for science funding.
ECS1@IYCr2014: Conveying a vision of modern crystallography
Authors: Oberti Roberta , Tarantino Serena , Zema Michele , Milanesio Marco , Berisio Rita , Moliterni Anna , Mealli Carlo
Published: November 2015

The first edition of the ECA European Crystallography School (ECS1), to be held in Pavia (Italy) during the course of IYCr2014, has found good balance between two apparently diverging goals: (i) to help students and young researchers to find their way in modern science, while keeping a special focus on the molecular and crystalline structure to interpret properties and functionality of materials; (ii) to raise the social and academic awareness of the great advances that crystallography has allowed and will allow to many branches of sciences. Students may choose between two formulae, i.e. a 6-day course with lectures and hands-on sessions held by renowned scientists, covering the state-of-the-art of crystallographic methods, theories and applications, at the same time indicating their future perspectives and cutting-edge aspects, or a 10-day Erasmus Intensive Programme, including a 3-day preparatory course and granting 3 ECTS credits. IYCr2014 is a unique opportunity to stimulate and ignite widespread interest in crystallography; therefore, some frontier seminars will be open to University faculty members, students, and to the general public. Efforts will be made to create a nice and friendly environment, with the goal to provide chances for future collaborations. Students will be invited to bring a poster showing their research results, projects or scientific interests. This will allow students to discuss their ideas with experienced crystallographers and favour aggregation. The programme received good support from scientific institutions and vendors, and a great response from the students: more than 110 pre-registrations from 33 countries were already received at the time this abstract was prepared, showing that there is a real need for both fundamental and advanced teaching in crystallography. We hope that this format will be continued and improved so as to provide a stable, periodic rendezvous for students and researchers under the common theme of crystallography.
Argentinian Association of Crystallography: IYCr activities and 10th anniversary
Authors: Baggio Ricardo , Botta Pablo , Di Salvo Florencia , Klinke Sebastián , Narda Griselda , Polla Griselda , Punte Graciela , Serquis Adriana , Vega Daniel , Lamas Diego
Published: November 2015

"The history of Crystallography in Argentina is very rich, probably starting with the pioneer work of Prof. Ernesto Galloni in the decade of the `40s. Thanks to Prof. Galloni, the National Committee of Crystallography was founded in 1958 and recognized by the IUCr in 1960. This committee organized several scientific meetings and was in good contact with the Ibero American Crystallography Group during about 35 years. After some crisis in the late `90s, some young crystallographers decided to reorganize the activities and form the Argentinian Association of Crystallography (AACr), which was finally founded on October 30th, 2004, on the occasion of the ""National Workshop on Crystallography"" held in Villa Giardino, Province of Córdoba. Therefore, in the International Year of Crystallography, the AACr is also celebrating its tenth anniversary. The regular annual events of the AACr are a scientific meeting, a school on Crystallography and a workshop. This year, they will be held in Mar del Plata (Province of Buenos Aires) in the period of October 27th-Novembre 7th. In addition, many other academic activities such workshops or postgraduate courses are being organized in the whole country. It is worth to remark the School on Fundamental Crystallography to be held in La Plata, followed by an Agilent-UNESCO-IUCr OpenLab in La Plata and Buenos Aires, in April-May. Moreover, taking into account that Crystallography is a field that needs more promotion in our country, the AACr decided to propitiate several educational and dissemination activities. They include a national crystal growing contest, promotion of Crystallography in high and primary schools through the National Fairs of Science of the Ministry of Education, dissemination talks for different audiences, exhibitions, etc. Acknowledgements: The AACr thanks all the crystallographers that are working hard in these activities: G. Echeverría, O. Piro, S. Suárez, M. Saleta, D. Tobía, R. Carbonio, G. Aurelio, J. Pedregosa, F. Doctorovich, S. Conconi, L. Baqué, F. Napolitano, S. Alconchel, C. Alvarez, A. Ares, C. Bernini, S. Brühl, M. Dailoff, M.A. Foi, M. Harvey, M.S. Lassa, S. Montoro, E. Pannunzio Miner, etc."
William Nunn Lipscomb, Jr – A Kentucky Colonel's Contribution to Boranes, Proteins and Atomic Structure
Authors: Krause Kurt
Published: November 2015

Any listing of important scientific figures in 20th century crystallography would certainly include William Nunn Lipscomb, Jr. He is notable for both the breadth and depth of his research and because of many former students and fellows who are still active in science. Beginning with graduate work in the 40s at Caltech with Linus Pauling, his scientific career spanned almost 7 decades and produced more than 660 publications. "The Colonel" as he was known by his students was a genius in choosing important and challenging areas in which to study. He is widely known for his work on borane chemistry, theoretical chemistry and protein structure and function. His work on the chemical structure and bonding of boron cage compounds led to insights into electron deficient bonding that resulted in the award of the Nobel Prize in Chemistry in 1976. He championed the use of various quantum-mechanical approaches, both empirical and ab initio, to address questions in chemistry and biochemistry. He is particularly known for work using partial retention of differential diatomic overlap (PRDDO), and early work leading to the development of extended Hückel methods. He was a pioneer in using quantum chemistry to address questions in enzymology. His group produced the structures of several proteins including carboxypeptidase A, the 3rd enzyme structure solved after lysozyme and ribonuclease A, and also the structure of the dodecameric enzyme, aspartate transcarbamylase. The structures of the T and R forms of this protein were the first detailed descriptions of the homotropic allosteric transition ever reported for an enzyme. Additionally, Professor Lipscomb mentored a huge number of important scientists whose work continues throughout the world today. Notably two former graduate students, Tom Steitz and Roald Hoffman have received Nobel Prizes. The list of other notable group members is too long to include here but includes Don Wiley, David Christianson, Eric Gouaux, Doug Rees, Michael Rossman, and Norbert Sträter among many, many others. I was fortunate to be a graduate student with him in the 1980s and am very grateful for his influence and mentorship. With so many important scientific contributions spread over such a long time span William Lipscomb's scientific legacy is certain to endure.
IYCr2014: "Crystals and Crystallography" at "Explore UT"
Authors: Hackert Marvin , Jacquemetton Lars
Published: November 2015

IYCr2014 is a unique opportunity for increasing the public awareness about the importance of crystallography, and promoting educational awareness of crystallography. Explore UT is a campus-wide open house of the University of Texas at Austin campus for the central Texas community that attracts thousands of visitors to campus each spring, including many busloads of school children and their teachers. We describe our experience at a booth for this event of presenting a variety of educational and learning tools to illustrate the benefits to society of 100 years of crystallography and the significance of IYCr2014. The exhibit featured posters, computer stations with web links and software, experiments and movies on crystal growth, lessons on symmetry, optical transform demonstrations, graphics software, as well as a variety of molecular models including 3D printed molecular models. Teaching structure/function concepts in chemistry, biochemistry, molecular biology, pharmacy, biomedical engineering, etc. has always been a challenge due to the inherent importance of understanding the role of 3D structure in order to understand function. Most students find it easier to understand the concepts when they have access to molecular models. For protein molecules, the sheer size and number of atoms involved make assembling molecular models from atomic parts impractical. Advances in computers and availability of high quality computer graphics software for the display of molecular models has helped, but does not replace the benefit of being able to hold and examine a physical model. We describe our experience using 3D printing technology to generate molecular models for use in the classroom and research laboratories to improve learning of structural concepts. See the IYCr2014 website for more information – http://www.iycr2014.org
IYCr2014: Online activities in Spain to attract and involve everyone
Authors: Ramajo Beatriz , García-Granda Santiago , Fernández-González Ángeles , Rodríguez-Terente Luis , Torre-Fernández Laura , Roces Laura , González-Malmierca Justo , Pastor Roberto , González-Seco Alfonso , González-González Jose , Covelo Berta
Published: November 2015

New technologies offer an emerging framework to spread scientific knowledge. New sites based on different platforms (blogs, websites, youtube channels, etc.) are born everyday with an informative and educational spirit. The success of such proposals lies in an increasingly growing interest of the general publicusing these tools as an easy, convenient and funnyway to share information. These technologies contribute to spread and promote the participation in the IYCr2014 activities by supporting all the activities organized under the IYCr2014 [1,2] in Spain,accessing an ever wider audience through the network. First, we have created an own website: www.iycr2014.info where all the information about the different activities (national and international) of the IYCr2014 are being posted. This website has a TV channel available where some events (workshops, exhibitions, conferences, activities for school children or public engagement events) are broadcasted. Both, website and TV channel, are being supported by means of the most popular social networks: facebook and tweeter. Besides, some of our actions are designed by the use of different network tools. As selected running activities, we shall present the Massive Open Online Course (MOOC) [3] about crystallization and crystallography. This course is builtby using an accessible language andwas thought to support Crystallization in the School Project. A second example is the Mobile application to the project: Sands of the world. This very complex project needs worldwide collaboration to collect samples of sand from as many beaches as possible around the world. A third application is the Online development of competitions such as The most relevant molecule in SpanishCrystallography and The Round Robin-Crystal phase identification. Acknowledgements: Financial support from Ministerio de Economía y Competitividad de España (MAT2010-15094, Factoría de Cristalización – Consolider Ingenio 2010) Figure: QR codes of the website (left) and the MOOC (right)
IYCr2014: Ongoing Activities around the ECA area
Authors: Garcia-Granda Santiago , Roces Laura
Published: November 2015

As the International Year of Crystallography is going on, the crystallographic community is actively involved in a number of activities and events to connect crystallography and society. The European Area, where the seminal discoveries took place, combines the traditional out-reach activities carried out during the last few years with several new activities to make crystallography and crystallization attractive to the public in general. The crystal growing competitions, involving high schools, organized since 2008 in Spain, are in 2014 very popular in the ECA Area. Since 2011, a Summer Scientific Campus has been held at the University of Oviedo in which the students develop a research project that incorporates crystallography as the core theme (X-Ray diffraction in the Forensic Science, Crystallisation and Mineralogy Workshops) [1]. An extension of that is the Spanish program for IYCr2014 "Science, Crystals and Society" [2]. For the European activities, the ECA Executive Committee created the IYCr2014 Coordination Committee, to gather initiatives in the ECA area and to be a link with the IUCr worldwide supervision of IYCr2014. "Discovering", "Getting involved" and "Communicating" are the three key points to connect scientists and society. The main objective of this project is to integrate and disseminate the science of crystallography into the European society, particularly among students, boosting the European dimension of the Project. "Discovering", "Getting involved" and "Communicating" are the three key points that will connect scientists and society. This European platform (http://www.iycr2014.eu) and the associated social networks content are the European links between crystallography and society using a number of tools: A dedicated IP/TV, ITunesU Chanel, or the Google Course Builder tool platform. Acknowledgements: Financial support from Ministerio de Economía y Competitividad de España (MAT2010-15094, Factoría de Cristalización–Consolider Ingenio 2010) and ERDF.
IYCr2014 in the « Midi-Pyrénées » Region, France
Authors: Daran Jean-Claude , Mourey Lionel , Seydoux Anne-Magali , Ratel-Ramond Nicolas
Published: November 2015

To promote crystallography through the "Midi-Pyrénées" Region, our association, « Les Cristallographes en Midi-Pyrénées » has scheduled different events from October 2013 until the end of 2014. These events will cover scientific demonstrations and/or lectures open to the general public. 1) Events - The Novela (7-12 October 2013), organized by the Toulouse-Metropole, is an event whose major goal is to share knowledge, in all its diversity, in a festive and popular spirit. It aimed at pupils and students as well as the general public. This will be performed once again in October 2014. - The "Kiosque-Actu" at the Toulouse Museum provides an opportunity to inquire and to exchange with researchers on a scientific topical subject. On the 2nd of February 2014, researchers coming from several laboratories in Toulouse (CEMES, CIRIMAT, GET, IPBS, and LCC; from the CNRS and the Paul Sabatier University) and involved in all domains of X-ray diffraction (Biology, Mineralogy, Chemistry, Materials, etc.) came to meet the general public and to demonstrate the importance of crystallography. Exhibition "Voyage dans le cristal / Journey within a crystal" at (i) the Philadelphe Thomas Museum in Gaillac (14 February-4 May 2014) and (ii) at the library of the Paul Sabatier University (from the 1st of September until the end of the year). Panels from this exhibition have been/will be also displayed during all events mentioned above. 2) Conferences - Maryvonne Hervieu (ENSICAEN, Caen, France), 17 February 2014, "Des cristaux et des hommes / Of crystals and men". - Jean-Claude Daran (LCC, Toulouse, France), 20 February 2014, "Les cristaux de Louis Pasteur / Louis Pasteur's crystals". - Lionel Mourey (IPBS, Toulouse, France), 27 February 2014, "Des cristaux au secours de la médecine / Crystals to help medicine". - Anne-Magali Seydoux (GET, Toulouse, France), 10 April 2014, "Effets de la radioactivité sur les structures des minéraux / Effects of radioactivity on the structure of minerals".
Some Crystallographic Activities Organized in Mexico
Authors: Bucio Lauro , Belio-Reyes Irma Araceli
Published: November 2015

The Mexican Society of Crystallography (SMCr) has 19 years old; 14 Regional Delegations (red points in the map below); has celebrated six national meetings (each one with audiences of around 250, red points with circles in the map below); and several courses, workshops, conferences along its lifespan. Also around 50 monographs have been produced, with some videos, games and souvenirs related with crystallography. A lot of them have been designed for improving the teaching of crystallography in graduate and postgraduate programs. Visits to the giant crystals of gypsum in the locality of Naica in the mexican state of Chihuahua, were organized by the SMCr with the kindly permission of Peñoles Company. Documents concerning to the history of crystallography in Mexico have been published by A. Cordero-Borboa [1-3]. On 2014, the SMCr will celebrate the IYCr,with organizing several activities and its seventh national meeting. With other Latin American countries will join to the initiative of found the Latin American Crystallographic Association (LACA) and its incorporation as Regional Associate of the International Union of Crystallography (IUCr). In the next images, circling the map of Mexico, starting from the upper left and following clockwise sense: cave of swords; gem (workshop on gemology); giant crystals of gypsum in Naica; crystal drawings (mineralogy for kids workshop); workshop on the Rietveld method; mineralogy for kids workshop; workshop on crystal growth of proteins.
IYCr outcome in SE Asia
Authors: Vittal Jagadese
Published: November 2015

Crystallography has been extensively practiced in a number of Asian countries such as India, China, Japan, S. Korea, Taiwan, Australia, New Zealand and Singapore, and to a lesser extent in Malaysia and Thailand for decades, but not in many parts of South East Asia. The International Year of Crystallography (IYCr 2014) provided an opportunity to reach out some of these countries to initiate or intensify the crystallographic activities in terms of workshops, conferences, crystal growing competition, etc. As a part of this initiative, the IUCr with the help of the Asian Crystallographic Association contacted various academicians and researchers in Malaysia, Thailand, Indonesia and Fiji to increase the awareness of the science of crystallography through various activities, to promote education and research in crystallography and to inspire young people through hand-on demonstration in school, among the activities planned in 2014. The speaker will collate the details of these activities and present in his talk. He will also discuss details of the Crystal Growing Challenge in Singapore among the other activities planned to celebrate IYCr 2014 in Singapore.
Doing Diffraction in an Absorption beamline
Authors: Figueroa Santiago , Falcão Matheus , Espindola Alexey , Da Silva Eleoterio Marcos , Sotero Levinsky Anna , Mauricio Junior , Zambello Fabio , Fonseca Vinicius
Published: November 2015

During the summer school program on the Brazilian Synchrotron Light Laboratory we adapt the XAFS2 beamline to do Diffraction experiments. This instrumentation work allows us to open a new window on the usual XAFS experiments, which is specially useful for combine the techniques obtaining information on short and long range order. We explore both techniques performing in situ studies with a capillary microreactor [1] exploring the hydrogen dessoption on metal hydrides (MgCo compounds) during a thermal treatment under helium atmosphere. The possibility to change between XAFS and XRD experiments in a few minutes and following the dessoption with a mass spectrometer give a complete picture of the changes in the material under operando conditions. This is a very promissing combination to explore catalysts or funtional materials increasing the research possibilities of the beamline.
Educational Outreach and User Training at the Worldwide Protein Data Bank
Authors: Battle Gary , Zardecki Christine , Haruki Nahoko , Kleywegt Gerard , Berman Helen , Nakamura Haruki , Conroy Matthew
Published: November 2015

The Protein Data Bank (PDB) contains a wealth of structural and functional knowledge about proteins, RNA, DNA, and other macromolecules, and their assemblies and complexes with small molecules. The challenge faced by the providers of PDB data is to make this knowledge accessible to an increasingly large and diverse audience, ranging from expert structural biologists to non-specialist consumers of structural information. Educators, students, and general audiences will have their own specific interests and expectations from molecular structure data. For a general user, a 2D image of hemoglobin illustrates how a protein looks at a microscopic level. For high school students and educators, 3D models or computer graphics can show how one or a few specific proteins can assemble into an icosahedral virus. In contrast, PhD and post-doc level researchers require expert guidance on how to critically assess the quality of structural data, and in-depth training on the use of specialist tools and resources for the comparison and analysis of structures. The PDB archive is managed by members of the Worldwide Protein Data Bank (wwPDB): the Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB; rcsb.org), Protein Data Bank in Europe (PDBe; pdbe.org), Protein Data Bank Japan (PDBj), and BioMagResBank (BMRB, bmrb.wisc.edu). In addition to managing and distributing structural data, the wwPDB partners are engaged in numerous outreach initiatives and user training programs. These efforts are vital to ensuring that these uniquely valuable data can be effectively accessed and used by research scientists, students, and educators alike. This talk will describe on-going wwPDB outreach efforts and highlight exciting new initiatives at the RCSB PDB, PDBe and PDBj.
Vernier structures of metal benzenedicarboxylats MIL-47 and MIL-53
Authors: Wang Xiqu , Jacobson Allan
Published: November 2015

The nanoporous frameworks VO(bdc), MIL-47, and M(OH)(bdc), MIL-53, bdc = 1,4-benzenedicarboxylate, can absorb various guest species in their 1D channels. As synthesized, the channels are filled with H2bdc molecules that have been reported to be disordered, except for In(OH)bdc·0.75H2bdc which has a Vernier structure with H2bdc molecules forming an ordered sublattice.[1] We have found similar Vernier structures in other members of the family based on X-ray data from large single crystals. The MO(bdc) framework consists of single chains of MO6octahedra that share trans corners and are bridged by bdc ligands. The guest H2bdc molecules form double columns in each channel parallel to the octahedral chains. Commensurate superstructures are observed, which result from mismatch between the basic periodicities of the guest and host sublattices, for [VO(bdc)](H2bdc)5/7, (1), (293 K, P21, a=23.903, b=17.191, c=25.722 Å, β=105.910), [Ga(OH)(bdc)](H2bdc)12/17, (2), (100 K, P21, a=17.707, b=11.730, c=114.639 Å, β=90.480), and [Al(OH)(bdc)](H2bdc)11/16, (3), (293 K, orthorhombic, a=12.278, b=17.059, c=105.488 Å). Different simple fractional numbers of H2bdc molecules per framework metal cation result from change in the basic periodicity of the octahedral chains due to different metal cation sizes. The octahedral chains are parallel to [201] in (1), and to [001] in (2) and (3). Remarkably, all atoms in (2) are observed to show significant transverse sinusoidal modulation along [001] direction. We thank the Robert Welch Foundation for financial support (Grant No. E-0024).
9,9'-Spirobifluorene Based MOFs: Synthesis, Structure, Catalytic Properties
Authors: Snejko Natalia , Iglesias Marta , Monge Ángeles , Benito-Hernández Ángela , Pintado Mercedes , Medina Manuela , Gutiérrez-Puebla Enrique
Published: November 2015

The 9,9'-spirobi[fluorene]-3,3',6,6'-tetracarboxylic acid (H4SBF), a ligand based on the spirobifluorene (SBF) core, was used as a ligand for the synthesis of the MOFs [Co(H2SBF)Phen(H2O)]n (1), and [M(H2SBF)(4,4´-Bipy)]n (M = Co, Ni, Cu) (2). The ligand H4SBF is based on the spirobifluorene (SBF) core: the interest in the SBF platform is due to its application as chiral ligand in organic electronics, as solid state laser or in third-order nonlinear optics. The MOFs with H4SBF have been obtained by hydrothermal reaction of H4SBF, the corresponding MCl2 and the base (Phen or 4,4´-Bipy) in a molar ratio H4SBF : M2+ : base = 1:1:1. The obtained MOFs are stable in air and thermally stable up to ~400°C. The MOFs 2 (M = Co, Ni, Cu) are isostructural (proved by DRXP data). Only for 1 and 2 (M=Ni) the crystals were obtained apt for crystallographic study. The Ni compound crystallizes in monoclinic system, Cc space group with cell parameters: 40.8251 Å, 12.0031 Å, 11.8383 Å and β = 104.3980, vol. 5618.89 Å3. Ni metal center is hexacoordinated in an octahedral environment with five O atoms of two ligands and one N atom from 4,4- Bipy, which means that there is another N atom not coordinated to metal center. The structure of 2 is 2D with interlayer H bonds, which built up a supramolecular 3D net. The Co compound is triclinic, P-1 space group with cell parameters: 10.9775 Å, 12.7231 Å, 14.2381 Å, α = 65.2030, β = 87.5280, γ = 72.9470, vol. 1718.6 Å3. Like Ni compound, Co metal center is hexacoordinated in an octahedral environment with three O atoms of one ligand, two N atoms from Phen and one water coordinated molecule, which builds up a 2D structure. To test the catalytic ability, the obtained MOFs were used to oxidize styrene molecules with tert-butyl hydroperoxide oxidant. Styrene was fully oxidized into its epoxidized product by 1 in CH2Cl2 in 6 h. Under the same conditions, 1 can oxidize the most inert cyclohexane substrate at 60°C with 80.6% substrate conversion.
Investigating valence tautomerism presence in compounds of Co and naphthoquinone
Authors: Ribeiro Marcos , Stumpf Humberto , Pinheiro Carlos
Published: November 2015

The search for new functional materials involves the development of bistable molecules exhibiting different electronic states with distinct properties at the ambient condition (temperature, pressure, illumination) of application. Coordination compounds, which present electron transfer between metal ion and an organic ligand associated with a change in electron multiplicity of the metal ion, are named valence tautomers(VT)[1]. The chemical equilibrium between two distinct electronic states in VT can be induced by temperature and pressure change as well as by soft X-ray and light irradiation. Thermodynamic and structural data highlighting the mechanisms of the valence tautomerism interconversion can be found in the literature for materials build up with cobalt and benzoquinones such as the 3,5-di-t-butyl-semiquinonate. However, to the best of our knowledge, there is no example of compounds showing VT build up with cobalt and naphthoquinones. In the present work 2-hydroxy-1,4-naphthoquinone (law) has been used as redox active ligands in the search for new VT compounds with cobalt. Three new coordination compounds of cobalt and 2-hydroxy-1,4-naphthoquinone (law), [Co(law)2(im)2], [Co(law)2(phen)] e [Co(law)2(bpy)] were synthesized and characterized by infrared (IR), UV-vis spectroscopy, electron paramagnetic resonance (EPR) and cyclic voltammetry. The three dimensional structures were determined using single crystal X-ray diffraction techniques. However, within the investigated temperature range neither X-ray diffraction nor EPR data showed the presence of VT in the materials, mainly due to the electrochemical properties of the 2-hydroxy-1,4-naphthoquinone. Nevertheless the structural features of the compounds as well as their supramolecular packing motifs suggest that naphthoquinones can be an alternative for the synthesis of compounds showing valence tautomerism[3].
X-ray and neutron scattering: from ideal zeolites to real guest-host systems
Authors: Porcher Florence , Souhassou Mohamed , Lecomte Claude
Published: November 2015

Tetrahedral MOFs, microporous metallophosphates and zeolites share common framework topologies despite very different chemical nature of their crystalline skeleton. In the case of zeolites or metallophosphates, the polymeric [TO2]_ framework is based on single tetrahedral atoms T (T= Si4+/Al3+ or Ga3+/B3+/P5+ respectively) connected by corner oxygen atoms O. In the case of MOFs, the skeleton is built from supertetraedra formed by a central metal atom complexed by 4 organic linkers (terephtalate,...); hence homologous structures expanded by a "scale factor". In "molecular sieves", the static porosity but also the "breathing effect" control, in first approximation, the adsorption and the self-diffusion of guest molecules. These latter are finely tuned by the interaction of these molecules with the framework itself (though H-bonds or electrostatic interactions), with charge compensating cations in basic zeolites (through coulombic interaction), or with other adsorbed molecules. However, the interplay between guest molecule adsorption, framework relaxation, cation redistribution and atomic charge transfer leads to an inextricable problem for the modeling and prediction of adsorption properties in these systems in absence of any polarizable and adaptive force field. We will present experimental charge density studies on activated industrial zeolites FAU, MFI and MOR. The electrostatic properties derived on these systems (electric field, atomics charges) are validated by a comparison with those derived, experimentally and theoretically, on a comprehensive set of simpler quartz-type materials (SiO2, AlPO4, GaPO4,...) representative of typical microporous compositions. Finally, we will combine the informations brought by diffraction, diffuse scattering and Monte-Carlo modelling to analyse the adsorption process or the role of the template in the stabilisation of the framework in these systems and in the famous MIL-53 MOF
Copper(II) complexes with 3-hydroxyquinoxaline-2-carboxylic acid
Authors: Kukovec Boris-Marko , Vila-Viçosa Diogo , Zbačnik Marija , Calhorda Maria José , Popović Zora
Published: November 2015

Hydrothermal and mechanochemical syntheses are extensively used to obtain metal coordination polymers of different dimensionalities. Transition metal complexes with carboxylate based ligands e. g. 3-hydroxyquinoxaline-2-carboxylic acid (3-OHquinoxH) are interesting due to the possible formation of porous structures suitable for gas storage and separation. 1D coordination polymer {[Cu2(3-OHquinox)2(SO4)(H2O)2]·4DMSO}n (1) was obtained by reaction of CuSO4and 3-OHquinoxH in dimethyl sulfoxide (DMSO) solution at room temperature, while mononuclear complex [Cu(3-OHquinox)2(H2O)2]·2DMSO (2) was formed under hydrothermal conditions. The X-ray crystal structure analysis revealed two differently coordinated Cu(II) ions in 1 (see figure). The first Cu(II) ion in 1 is octahedrally coordinated by two bridging O,O'-bidentate 3-OHquinox ligands and two water molecules in trans position, and the second Cu(II) ion by two bridging N,O'-bidentate 3-OHquinox ligands and one O,O'-bidentate sulfate ion. The Cu(II) ion in 2 is octahedrally coordinated by two N,O'-bidentate 3-OHquinox ligands and two water molecules in trans position. The reaction mixture was also grinded in a ball mill in the presence of H2O, DMSO or their mixture and the products were identified by powder X-ray diffraction (PXRD). The grinding under these conditions could not be used to prepare pure 1 nor 2, but rather a mixture of both 1, 2, reactants and new, still unidentified, phase. The complex 2 was also studied by DFT methods. The hypothetical complex with two O-bound DMSO molecules is more stable than 2 by 2.9 kcal/mol. The preference for the formation of 2, with two coordinated water molecules, must be assigned to the hydrogen bonds between coordinated water and crystallization DMSO molecules in the crystal structure of 2.
Towards Controlling the Valance Tautomer Interconversion Character by Solvation
Authors: Ribeiro Marcos , Stasiw Daniel , Shultz David , Pattison Philip , Raithby Paul , Pinheiro Carlos
Published: November 2015

Valence tautomers are bi-stable functional molecular materials in which it is observed charge transference between redox active ligands and a metallic center followed by the change of spin of the metal. Valence tautomerism (VT) interconversion is entropically driven and induced by external stimuli such as irradiation by light and soft X-rays and/or changes in temperature and pressure. VT interconversion is also associated with remarkable variations in optical and magnetic properties and and can be modulated with slight chemical changes [1]. Typical examples of valence tautomers are coordination compounds of Co and o-dioxolenes ligands [2]. Crystals of the [Co(diox)(4-X-py)2], where diox = 3,5-di-t-butylcatecholate/3,5-di-t-butylsemiquinonate, X=CN/NO2, py= pyridine, were initially studied with respect to low spin (LS) to high spin (HS) thermo and photoinduced VT interconversion. It was reported that [Co(diox)(4-CN-py)2] crystals become HS–Co3+ at temperatures below 110 K with cooperative VT interconversion whereas [Co(diox)(4-NO2-py)2] crystals present non cooperative VT interconversion [3]. Toluene and benzene solvates of [Co(diox)(4-NO2-py)2 and [Co(diox)(4-CN-py)2 have been prepared to investigate further the solvation effects on the VT interconversion properties. Analysis of the single crystal X-ray diffraction data obtained during cooling and heating at temperatures ranging from 293 K to 90 K indicated that [Co(diox)(4-CN-py)2] toluene and benzene as well as [Co(diox)(4-NO2-py)2].toluene solvate crystals undergo into non cooperative VT interconversion. The [Co(diox)(4-NO2-py)2].benzene crystal show a highly cooperative VT interconversion with a pronounced hysteresis. Intermolecular interactions between inlayer [Co(diox)(4-X-py)2] molecules are responsible for the VT interconversion in all compounds, however the VT interconversion cooperativity seems to be related with the strength of the Car–H...Odiox interactions and with the correspondent Co–Co separation. Thus solvation plays a key role in the definition of the VT interconversion nature. Acknowledgments: FAPEMIG, CNPq and CAPES grant 10030-12-3.
Two new platinum complexes containing a chelating safrole-derivative and amine
Authors: Kimpende Peter , Dinh Nguyen , Huan Trinh , Toan Duong Ngoc Toan , Van Meervelt Luc
Published: November 2015

A series of new platinum(II) complexes containing chelating safrole (or its derivatives) and various amines have been synthesized to evaluate their anticancer activity. Here we report the structure determination of [Pt((MeO)2Ph)(o-toluidine)Cl] (1) and [Pt((MeO)2Ph)(piperidine)Cl] (2), with (MeO)2Ph 3,4-dimethoxyphenyl-2-propene. Plate-like crystals of (1), suitable for x-ray diffraction measurement were obtained by slow evaporation from an ethanol solution. Rod-like crystals of (2) were harvested from ethanol after slow evaporation of acetone from an ethanol-acetone solution. Diffraction data were collected on a diffractometer equipped with a Bruker-AXS SMART 6000 CCD detector and integrated by the program SAINT. A multi-scan absorption correction was performed by the program SADABS. Both structures were solved by direct methods using the SHELXS program and refined according to the least-squares method to R-values of for 0.0204 (1) and 0.0280 for (2). The crystal of (1) to the orthorhombic space group P212121 and that of (2) belongs to the triclinic space group P-1. The asymmetric unit of (1) comprises one molecule of [Pt((MeO)2Ph)(o-toluidine)Cl]. The asymmetric unit of (2) consists of one ethanol molecule and one [Pt((MeO)2Ph)(piperidine)Cl] molecule. Both structures are similar with respect to the configuration and geometry of the Pt complex. Considering the centroid Cg of the allyl C=C bond as one ligand, the coordination geometry of Pt is square planar (other ligands are Cl, N (amine) and C (phenyl ring)). The angle between the best planes through the (MeO)2Ph and amine ligands is 84.3(1)0in (1) and 25.2(5)0in (2). The best plane through the allyl group makes an angle of 55.6(2)0and 56.4(4)0with the best plane through the (MeO)2Ph group, respectively in (1) and (2). The allyl double bond C=C is nearly perpendicular to Pt–Cg line, 89.8(2)0in (1) and 87.4(8)0in (2). For (1) the packing is essentially the result of van der Waals' interactions and two weak hydrogen bonds of type C-H...Cl and C-H...O. In (2) the packing is determined by the O-H...O hydrogen bond (O...O distance 2.870(4) Å) between ethanol and one of the methoxy substituents.