bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Phase Transition by FTIR/SAXS/WAXD Simultaneous Measurement System
Authors: Tashiro Kohji , Yamamoto Hiroko , Yoshioka Taiyo , Tahara Daisuke
Published: November 2015

FTIR/SAXS/WAXD simultaneous measurement system has been developed for the study of the structural phase transition behaviors of soft materials including crystalline polymers. The system consists of a transmission-type miniature FTIR spectrometer set around the sample stage and the 2-dimensional detectors for WAXD and SAXS measurements in a synchronized mode, as shown in Figure. The infrared and X-ray beams can pass through the same position of a sample, which is set on the various types of equipments such as a stretcher, a heater, a temperature-jump cell for isothermal crystallization, etc. The system has been successfully applied to the studies of the structural evolution processes of crystalline polymers. For example, an intimate relationship has been clarified between the structural change in the crystal lattice and the change in lamellar stacking mode during the stress-induced phase transition of poly(tetramethylene terephthalate). Another example is the study of phase transition of aliphatic nylons in the heating and cooling processes. So far the aliphatic nylons were considered to show the phase transition at a so-called Brill transition point, but the simultaneous measurement revealed another phase transition occurring in a temperature region immediately below the melting point. The structural evolution has been also studied for the isothermal crystallization process of crystalline polymer from the melt, as seen in the case studies of polyethylene, nylon, polyester, and so on. The concrete description was made for the regularization process viewed from the various hierarchical levels of molecular chain conformation, chain packing mode, and lamellar stacking mode or higher-order structure.
Watching nanocrystals form
Authors: Iversen Bo
Published: November 2015

Reactions in steel containers under solvo/hydrothermal conditions are widely used to produce crystalline nanoparticles. The solvo/hydrothermal approach often provides excellent control over nanoparticle characteristics such as size, size distribution, morphology and crystallinity. However, most progress in the solvothermal field is empirical in nature. Recent development of in situ X-ray scattering techniques now allow real time monitoring of the formation of nanoparticles under high pressure, high temperature conditions, and this opens up the possibility for synthesizing nanoparticles by design. We have developed unique in situ reactors for studies of reactions in sub- and supercritical fluids [1]. By means of Small Angle X-ray Scattering (SAXS), Wide Angle X-ray Scattering (WAXS), Total scattering and EXAFS we have obtained knowledge on the formation and growth of a range of important nanoparticles all the way from the precursor structures to the final crystalline product. In the talk recent examples will be discussed. [1] (a) Jensen et al., Angew. Chem. 2007, 46, 1113; (b) Bremholm et al., Angew Chem. 2009, 48, 4788; (c) Bremholm et al., Adv. Mater. 2009, 21, 3572; (d) Lock et al, Angew Chem. 2011, 50, 7045; (e) Jensen et al., J. Am. Chem. Soc. 2012, 134, 6785; (f) Tyrsted et al, Angew. Chem. 2012, 51, 9030; (g) Nørby et al., RSC Adv. 2013, 3, 15368; (h) Eltzholtz et al., Nanoscale 2013, 5, 2372
The LGN:Insc tetramer stabilises the apical site in asymmetric cell divisions
Authors: Culurgioni Simone , Mari Sara , Gallini Sara , Bonetto Greta , Mapelli Marina
Published: November 2015

Asymmetric cell divisions regulate the position and the fate choice of daughter cells, with impact on developmental programs and tissue homeostasis. The asymmetric outcome of a stem cell division relies on the coordination between cortical polarity and the orientation of the mitotic spindle. To date the adaptor Inscuteable (Insc) is considered the molecular bridge between cortical polarity proteins and the spindle tethering machinery assembled on NuMA:LGN:Gαi. Insc interacts with the polarity protein Par3, and competes with NuMA for the binding to LGN [1]. I will present the crystallographic structure of Drosophila LGN in complex with the asymmetric domain of Insc. The structure reveals a tetrameric arrangement of intertwined molecules, and is compatible with the concomitant binding of Insc to LGN and Par3. Binding assays indicate that Insc interacts directly with the PDZ region of Par3. The finding that LGN enters a stable tetrameric complex with Insc and Par3 suggests a novel function for LGN in stabilizing the apical site, where polarity proteins enrich during asymmetric cell divisions. I will propose a revised model for mitotic spindle coupling to polarity cues based on the dual role of LGN in organizing microtubule motors when in complex with NuMA and Dynein, and securing their cortical attachment when bound to Insc and Par3.
Structure-based classification of ice-binding proteins
Authors: Do Hackwon , Lee Chang Woo , Lee Jun Hyuck
Published: November 2015

Since the antifreeze protein (AFP) super family has low structural identity, classification standard of the AFPs is presently ambiguous. Newly identified ice-binding proteins (IBPs), named so after the function of the AFPs, have similar structural identity and function that interact to the ice. Identification and characterization of IBPs from the eukaryotic microorganisms Typhulaishikariensis (TisAFP) and Leucosporidium sp. (LeIBP) revealed that both are glycosylated and have irregular motif on the ice-binding site (IBS). The IBPs share a unique right-handed β-helix, which provides an advantage of broad-range interaction surface. The other IBP encoded by the Antarctic bacterium Flavobacterium frigoris PSI was determined at 2.1-Å resolution to gain insight into its ice-binding mechanism. The structure of FfIBP shows the presence of an intra-molecular disulfide bond in the loop region between α2 and α4 (capping region), unlike that of LeIBP and TisAFP. Electron density for this disulfide bond was seen between Cys107 and Cys124 during the structure refinement process and the Cβ–Cβ distance between Cys107 and Cys124 was 3.9 Å. By sequence alignments and structural comparisons of IBPs, we defined two groups within IBPs, depending on the sequence differences between the α2 and α4 loop regions and the presence of the disulfide bond. In addition, to investigate the effects of the capping region on the activity and stability of FfIBP, we determined the crystal structure and measured the thermal stability of mutants that swapped the capping region of FfIBP and LeIBP (mFfIBP and mLeIBP). In thermal denaturation experiments, it is clear that the capping-head region of FfIBP is more stable than that of LeIBP and is important for the overall stability of IBP, although it is not directly involved in the antifreeze activity.
The first ribonucleotide reductase without an activating radical cysteine
Authors: Aurelius Oskar , Johansson Renzo , Bågenholm Viktoria , Lundin Daniel , Balhuizen Alexander , Beck Tobias , Sjöberg Britt-Marie , Mulliez Etienne , Logan Derek
Published: November 2015

Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides, the building blocks for DNA synthesis, and are found in all but a few organisms. RNRs use radical chemistry to catalyze the reduction reaction. Despite RNR having evolved several different mechanisms for generation of different kinds of essential radicals across a large evolutionary time frame, for over 30 years the paradigm has been that this initial radical is always channeled to a strictly conserved cysteine residue directly adjacent to the substrate for initiation of substrate reduction. Such a cysteine residue has been present in the structure of each of the many RNRs determined to date. We present the crystal structure of an anaerobic RNR from the extreme thermophile Thermotoga maritima (tmNrdD), both alone and in complex with allosteric effector dATP and substrate CTP. Remarkably, tmNrdD lacks a cysteine for radical transfer to the substrate, and is the first structurally or biochemically characterized RNR to do so. However in many other respects tmNrdD appears to be a normal anaerobic RNR, including gene structure, expression levels, metal cofactor and binding of allosteric effectors and substrates in the expected conformations. Furthermore, it is possible to generate a glycyl radical as expected. We present evidence that the structure of tmNrdD is representative for the new RNR subclass IIIh, present in all Thermotoga species plus a wider group of bacteria from the distantly related phyla Firmicutes, Bacteroidetes and Proteobacteria, all lacking the canonical cysteine residue. The wide distribution provides further evidence that the subclass IIIh is a functional RNR. Taken together, the results imply that an alternative initiation route for the RNR reduction reaction must exist that do not require channeling through a cysteine side chain.
Fibrillar Collagen Trimerization: Structural Basis and Related Genetic Disorders
Authors: Sharma Urvashi , Mariano Natacha , Hulmes David , Aghajari Nushin
Published: November 2015

The C-propeptides of fibrillar procollagens play crucial roles in tissue homeostasis and remodeling by controlling both the intracellular assembly of procollagen molecules and the extracellular assembly of collagen fibrils. Mutations in the C-propeptides affecting molecular assembly are associated with several, often lethal, genetic disorders affecting bone, cartilage, blood vessels and skin. Cells often produce multiple collagen types, each with the correct chain composition. In fibrillar collagens, molecular assembly begins with the C-propeptides which contain chain recognition sequences specific for each collagen type. Our recent crystal structure of a C-propeptide trimer from procollagen III (Bourhis et al, 2012), revealed specific interactions at the trimer interface. Unlike collagen III, a homotrimer, collagen I is normally a heterotrimer, though small amounts of homotrimer are found in embryonic tissue and cancer. To investigate the molecular basis of homo- versus hetero-trimer formation, further structural information is required. We have initiated structural studies on homo- and hetero-trimers of the C-propeptide domain of human procollagen I, to study the molecular basis of chain selectivity within the same cells. CPI homotrimer crystallizes in the monoclinic spacegroup P21, and data were collected to 2.2 Å resolution. The crystal structure solved by MR shows a structure resembling CPIII with the overall shape of a flower. At the trimerization interface however, interactions between chains are specific to CPI and these give insights into the mechanism of molecular recognition. These interactions will be compared to those in CPIII. Structural mapping indicates striking correlations between the sites of numerous disease-related mutations in different C-propeptide domains and the degree of phenotype severity. The results have broad implications for the understanding of genetic disorders of connective tissues and also for new therapeutic approaches against fibrosis.
A two-domain elevator mechanism for sodium/proton antiport
Authors: Lee Chiara , Kang Hae Joo , von Ballmoos Christoph , Newstead Simon , Uzdavinys Povilas , Dotson David , Iwata So , Beckstein Oliver , Cameron Alexander , Drew David
Published: November 2015

Sodium/proton (Na+/H+) antiporters, located at the plasma membrane in every cell, are vital for cell homeostasis. In humans, their dysfunction has been linked to diseases, such as hypertension, heart failure and epilepsy, and they are well-established drug targets. The best understood model system for Na+/H+ antiport is NhaA from Escherichia coli, for which both electron microscopy and crystal structures are available. NhaA is made up of two distinct domains: a core domain and a dimerization domain. In the NhaA crystal structure a cavity is located between the two domains, providing access to the ion-binding site from the inward-facing surface of the protein. Like many Na+/H+ antiporters, the activity of NhaA is regulated by pH, only becoming active above pH 6.5, at which point a conformational change is thought to occur. The only reported NhaA crystal structure so far is of the low pH inactivated form. Here we describe the active-state structure of a Na+/H+ antiporter, NapA from Thermus thermophilus, at 3 Å resolution, solved from crystals grown at pH 7.8. In the NapA structure, the core and dimerization domains are in different positions to those seen in NhaA, and a negatively charged cavity has now opened to the outside. The extracellular cavity allows access to a strictly conserved aspartate residue thought to coordinate ion binding directly, a role supported here by molecular dynamics simulations. To alternate access to this ion-binding site, however, requires a surprisingly large rotation of the core domain, some 200against the dimerization interface. We conclude that despite their fast transport rates of up to 1,500 ions per second, Na+/H+ antiporters operate by a two-domain rocking bundle model, revealing themes relevant to secondary-active transporters in general.
Crystallography for the People
Authors: Warren Anna , Thomas Lynne , Murray Claire
Published: November 2015

The British Crystallographic Association (BCA) has engaged in public outreach projects over the past two years, aimed at communicating the basic principles and applications of crystallography to the general public, especially in light of the Bragg Centenary Celebrations and the International Year of Crystallography. Based on an activity developed by the Young Crystallographers group of the BCA called "The Structure of Stuff is Sweet", we have developed a pack which can be used as a walk-up stand at science fairs and festivals, workshops and as science busking in pubs. The activities all focus on highlighting the relevance of crystallography to everyday life and are eye-catching to attract an audience. The biggest of the activities has been the UK Big Bang Fair which took place in both March 2013 and March 2014 in London and Birmingham, respectively. This is a very large science fair for schools and families to learn about different aspects of Science and Engineering, with over 75,000 people attending. The Science and Technology Facilities Council in the UK and the BCA funded a crystallography stand in collaboration with Diamond and ISIS. The stand had appeal to both young and old alike, and there was the opportunity to make unit cells from marshmallows, crystallise lysozyme, and to learn about the principles of diffraction using a lego beamline! We had a team of around 40 volunteers from Universities and institutions across the UK covering biological, chemical and physical crystallography. An outline of the events, pictures and comments from participants are presented, as well as our plans for future events building on these foundations to further strengthen the BCA's engagement with the wider community and to raise the profile of crystallography in the public domain. Please come to the poster to find out more about the BCA, and what we do.
Crystallography for teachers
Authors: Serquis Adriana , Baqué Laura , Napolitano Federico , Soldati Analía , Lamas Diego
Published: November 2015

In this work we present and analysis of the influence of workshop activities performed in our city regarding the dissemination of crystallographic science in all educational levels. The organized workshops in honor of the IYCr are aimed to introduce crystallography to elementary and high schools teachers. The main goal is to improve teachers' knowledge in crystal formation and its techniques. This will allow teachers to elaborate laboratory projects that include crystallography principles according to their own students' level and to encourage the participation in the national and international crystal growing competition. Topics: 1. Introduction to crystallography 2. Atomic structure, chemical bonds and periodic table 3. Types of crystalline solids: metallic, ionic and covalent 4. Crystalline systems 5. Introduction to structure determination using X-ray diffraction 6. Crystal growing
Celebrating crystallography from K to 12 at CIMF, Montreal
Authors: Pillot Paul , Heron Paul , LowKam Clotilde , Barbier Vincent , Beylich Françoise , Chambon Anne-Laure , Falletto Jocelyne , Leroux Morgane , Pelé Joelle , Sygusch Jurgen , Kajetanek Dominique , Kremer Celia , Legris Magali
Published: November 2015

If crystallography is well known to many scientists, this is not true for the general public. Aims of the international year of crystallography include the desire to increase public awareness, to stimulate the intellectual curiosity of students and to promote crystallographic education. At the College International Marie de France, we decided to tackle these challenges and celebrate IYCR2014 with students from kindergarten to grade 10 and by an outreach with the Universite de Montreal (UdeM). We will illustrate how, beyond appreciating the mesmerizing ordered crystal growth from a saturated solution, studying and performing crystallization activities has a proven track record for fostering academic and practical skills. If crystallography starts by the Bragg's iconic law, then most undergraduate students will not appreciate it. However, crystals do have an intrinsic aesthetic appeal that can serve as a starting point to stimulate students' interest. Instead of teaching crystallography as a discipline, could we not teach key scientific concepts through it? We devised three distinct approaches addressing skills and notions appropriate to students in kindergarten, primary or grade 10 school levels. Younger pupils can make descriptions, comparisons and learn about symmetry and growth based upon the observation of snowflakes or crystal growth from solution, encouraging them to formulate basic concepts regarding solubility and changes in states of matter. Growing crystals allows primary students to practice mathematical skills such as measuring angles, masses, volumes and describing shapes. This sets the stage for problem solving using the scientific method. Older students take part in workshops ranging from diffraction patterns generated by lasers to simulating growth with cellular automata. They also undertake protein crystallization experiments in partnership with UdeM thereby offering unique access to crystallographic facilities and insight into scientific research.
Crystallography on Stage: Presenting the Concepts and History Dramatically
Authors: Abad-Zapatero Celerino , Campbell Jill , Gerhardt Gregory
Published: November 2015

From Christopher Marlowe's Doctor Faust (1604) to Oxygen (2000) by Carl Djerassi and Roald Hoffmann, there is a long tradition of dramatic work related to science and scientist. More recently, the enormously successful Copenhagen (1998) by Michael Frayn's and a wave of new plays about scientific themes such as Arcadia, Wit, After Darwin and others have created new dramatic phenomenon. These works are not the conventional documentary-dramas about scientific discovery but engaging plays. A recent book entitled Science on Stage (1) reviews more than a hundred plays presenting scientific themes on stage. Beginning in 2005, a play was developed with the objective of conveying the concepts and history of crystallography to large audiences in a dramatic setting. The script centers on the mural drawn by Picasso in 1950 at the flat of the iconic crystallographer J.D. Bernal, during his historical meeting with the world-famous artist. The main characters discuss the concepts of crystallography and explore the interconnections between Science and Art. The script has had several readings in academic settings (University of Illinois at Chicago, 2007; Barcelona, Zaragoza, Spain, 2008). The première staged reading of the play was produced at Argonne National Laboratory on May 4th2008. Details can be found at http://www.aps.anl.gov/Users/Meeting/2008/Picasso/index.php. The project has developed from an initial script entitled `Picasso Meets Crystallography' emphasizing the concepts and history of crystallography to the more dramatically-rich version entitled `Bernal's Picasso', which explores the relationships between Science and Art and is intended for wider theater audiences. The presentation will discus the history of the project with vignettes of previous performances, its multiple facets and its future development as a novel way to convey crystallography to wider audiences, and to explore in a dramatic context the role of crystallography in today's society
Talking and writing about science: different ways of popularization
Authors: Ivanenko Alisa
Published: November 2015

In the following contribution certain types of activities established in Russia within the last decade, which are devoted to popularization of science in particular crystallography, will be highlighted. Some of these projects have already been launched and could be recognized as both successfully and fast developing. Some of these events will take place during the International Year of Crystallography 2014. The most exciting event, at this present time, is the creation of a science café. This will involve lectures from top-ranked scientific experts taking place in a very informal atmosphere, for example in the café, gallery, park or another public place. Open discussions as well as games or questions from the lecturer to audience and vise versa could also take place here. Such project, namely "Science Café Eureka!", led to the bigger conception of a Science Festival, "Eureka!fest", to be held in Novosibirsk in May 2014. The festival structure is based on the "edutainment" format which means a combination of education and entertainment as a brand-new way of information exchange. A significant part of the comprehensive Festival program will be directly related to crystallography in honor of the International Year of Crystallography 2014. Another example of education in an informal environment is the Summer School of Russian Reporter Magazine. Originally supposed to be a journalistic event, this school has become a great place for spreading scientific knowledge to a very diverse audience in terms of both age and educational background. It should be noted that Summer School supports scientific journalism (not journalism about science which can be regarded as completely different) as an important tool of spreading up-to-date advances in science in a very accessible manner.
Halide-bridged Polymers of d10Metals with Heterocyclic Type Donor Ligands
Authors: Slabbert Cara , Rademeyer Melanie
Published: November 2015

Molecular self-assembly of organic ligands and inorganic metal halides leads to the formation of layered nano-composite organic-inorganic hybrid materials. The formation of both ionic- and coordination hybrids is possible. Both of these materials have attracted much attention recently in the field of Crystal Engineering [1], due to the retention and combination of desired inherent properties of both constitutional moieties, which then renders these materials multifunctional with a wide range of potential technological applications. Properties attributed to the organic component include structural diversity and optical properties [2], with mechanical hardness, electronic-, magnetic- and optical properties ascribed to the inorganic component. The coordination of an organic amine functionality to a metal halide results in the formation of halide-bridged polymers coordinated to donor ligands, with reported properties including non-linear optic (NLO) behavior, magnetic properties [3] and electronic semi-conduction. Literature confirms the technological importance of these materials and identifies the need for research aiming at a fundamental understanding of factors that control the observed structural trends and to relate chemical composition and topology of these compounds to ultimately enable retrosynthesis from desired property. In this study, a range of different divalent d10metal halides are combined with different aromatic nitrogen-containing organic ligands. The effects of change in metal atom, halide atom, stoichiometry and reaction conditions on the structural trends in the crystal systems are investigated. The molecular self-assembly of the said halide-bridged polymers is initiated by simple synthetic techniques under relatively mild conditions, at the most, hydrothermal reaction conditions. Structural characterisation was done employing single crystal X-ray diffraction, while bulk composition of the samples was investigated using powder X-ray diffraction.
Capture of face-to-face π-interactions via solid-state [2+2] photodimerization
Authors: Sinnwell Michael , MacGillivray Leonard
Published: November 2015

The use of principles of supramolecular chemistry to direct reactions in the crystalline state has emerged as a reliable means to facilitate highly selective reactions in a solvent-free environment. In this context, we exploit metal-organic complexes to fix spatial arrangements of molecules in crystal lattices to promote intermolecular [2+2] photodimerizations. Perfluorophenyl-perfluorophenyl interactions have recently emerged as a means to control supramolecular architectures and frameworks. However, it was not clear whether perfluorophenyl-perfluorophenyl interactions can be integrated in [2+2] photodimerizations in solids. In this presentation, we report a crystalline metal–organic complex with perfluorophenyl groups that adopt a well-defined face-to-face and head-to-head geometry in the solid state. Argentophilic forces are employed to enforce the face-to-face geometry. We demonstrate olefins of the solid to undergo a [2+2] photodimerization with UV-irradiation in a regiospecific and quantitative manner. In essence, we have employed the photoreaction as a means to covalently capture parallel perfluorophenyl-perfluorophenyl interactions in a solid.
Crystal structure of salts luminol with Li, Na and K
Authors: Rybakov Victor , Chernyshev Vladimir , Paseshnichenko Ksenia , Sheludyakov Victor
Published: November 2015

The molecular and crystal structures of new drugs Tamerit® (A) and Galavit® (B) which possess high effective immunomodulator, anti-inflammatory and anti-oxidant properties, were studied by single crystal and powder X-ray diffraction methods. As shown, A and B are aminodihydrophtalazindion (luminol) sodium salts, but A - is a dihydrate form and B anhydrous one, moreover it is a mixture two different crystal phases B1 and B2. The phase transition B1 <---> B2 is not registered by DSC method [1]. Crystal data for A: monoclinic system with a = 8.3429(4), b = 22.0562(11), c =5.2825(2) Å, β = 99.893(3)o, V = 957.59(8) Å3, Z = 4, sp.gr. R21/s. Crystal data for B1: monoclinic system with a = 14.7157(18), b = 3.7029(19), c = 16.0233(15) Å, β = 116.682(13)o, V = 780.1(4) Å3, Z = 4, sp.gr. R21/s. Crystal data for B2: orthorhombic system with a = 27.7765(15), b = 3.3980(19), c = 8.1692(19) Å, V = 771.0(5) Å3, Z = 4, sp.gr. Pna21. As a continuation of this work, we studied by the same methods other luminol salts: with Li - monohydrate (C1) and anhydrous (C2) and with K - trihydrate (D1) and anhydrous (D2). Crystal data for C1: monoclinic system with a = 13.0311(15), b = 9.6002(7), c = 7.3227(7) Å, β = 101.320(9)o, V = 898.26(15) Å3, Z = 4, sp.gr. R21/s. Crystal data for C2: monoclinic system with a = 13.0979(14), b = 8.7537(12), c = 14.5358(17) Å, β = 107.061(16)o, V = 1593.3(4) Å3, Z = 8, sp.gr. C2/c. Crystal data for D1: monoclinic system with a = 10.6760(6), b = 14.2905(8), c = 7.4902(5) Å, β = 99.246(5)o, V = 1127.90(12) Å3, Z = 4, sp.gr. R21/s. Crystal data for D2: orthorhombic system with a = 27.3961(19), b = 3.6811(14), c = 8.6672(12) Å, V = 874.1(4) Å3, Z = 4, sp.gr. Pna21 [2]. All X-ray experiments were made at T = 295 K. The features of molecular and crystal structures are discussed.
Crystal Structures of Four Novel Thiophene/Phenyl-piperidine Hybrid Chalcones
Authors: Parvez Masood , Bakhtiar Muhammad , Baqir Muhammad , Zia-ur-Rehman Muhammad
Published: November 2015

Chalcones constitute an important class of bioactive drug targets in the pharmaceutical industry that includes anti-ulcerative drug sofalcone. In continuation of our work, the crystal structures of four closely related 1-phenyl-piperidine based chalcones will be presented. I: C19 H21NOS, MW = 311.43, T = 173(2) K, λ = 0.71073 Å, Orthorhombic, P b c a, a = 10.1045(4), b = 10.5358(4), c = 30.6337(12) Å, V = 3261.2(2) Å3, Z = 8, Dc = 1.269 Mg/m3, F (000) = 1328, R [I>2σ(I)] = 0.059. II: C18H19NOS, MW = 297.40, T = 173(2) K, λ = 1.54178 Å, Orthorhombic, P b c a, a = 8.9236(2), b = 11.0227(2), c = 30.8168(6) Å, V = 3031.21(11) Å3 Z = 8, Dc = 1.303 Mg/m3, F (000) = 1264, R [I>2σ(I)] = 0.035. III: C18H19NOS, MW = 297.40, T = 173(2) K, λ = 1.54178 Å, Orthorhombic, P b c a, a = 8.82990(10), b = 11.0061(2), c = 31.2106(5) Å, V = 3033.13(8) Å3, Z = 8, Dc = 1.303 Mg/m3, F (000) = 1264, R [I>2σ(I)] = 0.048. IV: C18H18ClNOS, MW = 331.84, T = 173(2) K, λ = 0.71073 Å, Monoclinic, P 21/c, a = 14.1037(4), b = 11.3153(3), c = 10.1290(2) Å, β = 101.1367(14)0, V = 1586.02(7) Å3, Z = 4, Dc = 1.390 Mg/m3, F (000) = 696, R [I>2σ(I)] = 0.038. The crystals of I, II and III are isomorphous. In all structures, the piperidine rings are in chair conformations, thiophene rings are essentially planar and the C=C bonds in the prop-2-en-1-one fragment adopt E-conformation. All crystal structures are devoid of any classical hydrogen bonds. However, non-classical hydrogen bonding interactions of the type C---H...O in compounds II, III and IV link the molecules into chains extended along the b-axis. Moreover, C---H...Cg interactions involving thiophene rings in I and III and benzene ring in IV and π...π interactions between benzene rings lying about inversion centers are present in II and III.
Synthesis and structural characterization of four related α-phosphonates
Authors: Ouahrouch Abdelaaziz , Taourirte Moha , Lazrek Hassan Bihi , El Azhari Mohamed , Engels Joachim , Bats Jan
Published: November 2015

α-Aminophosphonates are structural analogues of natural amino acids. They have been the subject of considerable attention due to their potential biological activities. They may be applied as enzyme inhibitors , antibacterial agents , antitumour agents or antiviral agents [4]. α -Aminophosphonates can be synthesized via the Kabachnik–Fields reaction [5] by the coupling of a carbonyl, an amine and a dialkyl phosphite unit. We report here the synthesis and crystal structures of four diethyl [(arylamino)(4-ethynylphenyl) methyl] phosphonate derivatives, namely diethyl [(4-bromoanilino) (4-ethynyl-phenyl) methyl] phosphonate, (I), diethyl ((4-chloro-2-methyl-anilino) {4-[2-(trimethylsilyl) ethynyl] phenyl} methyl) -phosphonate, (II), diethyl ((4-fluoroanilino) {4-[2-(trimethyl-silyl) ethynyl] phenyl} methyl) phosphonate, (III), and diethyl [(4-ethynylphenyl) (naphthalen-2-ylamino) methyl] phosphonate, (IV). The X-ray analysis confirms the structures found (Fig. I-IV), the products was crystallized by slow evaporation of ethyl acetate/n-hexane solution [3].
Non-covalent interactions of Acipimox in Multi-component Crystals
Authors: Maurel Vaughan , Dare Nicola , Bourne Susan , Caira Mino
Published: November 2015

The hypolipidemic agent acipimox has various potential hydrogen bonding donor and acceptor sites. A series of multi-component crystals can be formed owing to these moieties. Acipimox forms such structures with benzamide, isonicotinamide and urea. Each of these systems has a unique hydrogen bonding arrangement leading to changes in the physicochemical properties of acipimox. X-ray analysis of a hydrated co-crystal, acipimox·benzamide·0.5H2O (space group C2/c) revealed layers of dimeric acipimox-benzamide units, the layers being linked by hydrogen bonding from a bridging water molecule. A salt with formula (acipimox)- (isonicotinamide)+ (space group P2(1)/c) results from proton transfer from the carboxyl group of acipimox to the pyridyl nitrogen of isonicotinamide. The carboxyl group engages in an electrostatic interaction with the protonated pyridyl nitrogen. In addition, a hydrogen bond is formed between the donor amide and the acceptor carboxyl group of a second acipimox anion. These form a macrocyclic structure composed of two pairs of acipimox-isonicotinamide counterions in a R44(22) H-bonded motif, giving rise to interlaced layers. Acipimox and urea form two distinct systems, both crystallising in the space group P(-1). The kinetic crystallisation product is a co-crystal with 1:1 acipimox:urea stoichiometry (R22(8) motif), a second distinct urea molecule self-assembles forming infinite chains within channels formed by the packing arrangement. The thermodynamic form is an acetonitrile solvate in which the solvent molecules are included in isolated sites. The different H-bonding systems in each of these multi-component crystals give rise to differing physicochemical properties. For example the melting and degradation temperatures for each of these systems is distinct: that of the acipimox·benzamide co-crystal is lower than that of acipimox while the crystals containing isonicotinamide and urea have higher melting and degradation temperatures.
Gas Phase Single Crystal Growth of Coordination Networks
Authors: Kojima Tatsuhiro , Choi Wanuk , Kawano Masaki
Published: November 2015

Organic ligands and metal ions can produce several kinds of networks depending on experimental conditions, such as solvent, temperature, reaction speed, and so on.1, 2 While many MOF chemists have used solution phase reaction, recently some unique networking methods have been investigated, e.g. mechanochemical solid state reactions. Here we report a new method for single crystal growth of porous coordination networks via gas phase. In our previous work, we found that heating of interpenetrated network [(ZnI2)3(TPT)2]n (solvent) forms a crystalline powder, [(ZnI2)3(TPT)2]n (1, TPT = 2,4,6-tris(4-pyridyl)triazine).3 We determined a porous saddle-type structure of 1 by ab initio PXRD analysis. Interestingly, we could not prepare 1 by grinding and heating the starting powder materials of ZnI2 and TPT. Therefore, we attempted to prepare coordination networks via gas phase. On heating of ZnI2 and TPT together under reduced pressure in a glass ample at high temperature, single crystal growth of 1 was observed. The single crystal X-ray structure analysis revealed that 1 has the same structure as microcrystalline powder of 1. In gas phase, because there is no solvation effect, network topology is purely based on ligand interactivity and geometry of metal coordination. Therefore, saddle-type network is one of the possible patterns on the basis of geometry of only TPT and ZnI2 without guest molecules. To the best of our knowledge, this is the first example of single crystal growth of porous coordination network via gas phase. In summary, we successfully demonstrated the first gas phase single crystal growth of porous coordination network formation. In this presentation, we will discuss network design by gas phase reaction based on ligand interactivity focusing on weak intermolecular interaction.
Tuning colour in multi-component complexes: Molecular disorder as a design tool
Authors: Jones Charlotte , Wilson Chick , Thomas Lynne
Published: November 2015

The key aim of multi-component crystallisation is modification of the physicochemical properties for a specific task.[1] Tuning colour using molecular components is a relatively unexplored area, which is surprising given the possible advantages in pigment development. In crystalline materials, the optical characteristics are not solely dependent on the molecules but also on the crystal packing;[2] it follows that the optical properties could be modified using crystal engineering techniques. We have systematically investigated co-crystallising haloanilines with dinitrobenzoic acids to build an understanding of the intermolecular interactions. Molecular disorder of one or more of the components tends to lead to layered crystal structures that include stacking interactions and therefore strong colour, indicating that molecular disorder is desirable. Defects in inorganic systems are routinely exploited as a route to enhancing or introducing physical properties but similar effects in organic systems are yet to be properly exploited. We will discuss the methods by which disorder can be designed into molecular complexes, and the local ordering effects which give rise to strong diffuse scattering. Additionally we have identified a pair of thermochromic molecular complexes, 2-iodoaniline/2-bromoaniline 3,4-dinitrobenzoic acid, where disorder appears to be crucial in lending the materials their properties. Both complexes undergo a temperature-induced colour change from red to yellow corresponding to a significant molecular rearrangement. The thermochromic transition is a single-crystal to single-crystal effect; the role of molecular disorder as a facilitator for the molecular rearrangement, maintaining the crystal integrity, will be discussed. Despite the complexes being isostructural, only the bromoaniline complex shows reversible thermochromic behaviour; subtleties in the manifestation of this disorder can explain the differences in the reversibility of the transition.
Co-crystals of leucyl-alanine
Authors: Fillion Travis , Soldatov Dmitriy
Published: November 2015

Although the ability of different molecules to crystallize in a single solid has been known for a long time [1], some of these materials became a subject of intense studies in the last decade due to pharmaceutical and other applications [2]. Short peptides may become a very useful class of co-crystallization agents due to their wide diversity, eco-friendliness and biocompatibility [3]. In this work, we screened the dipeptide leucyl-alanine (LA, see Figure) for the ability to form co-crystals with a variety of solid bioactive compounds. Solvent-assisted grinding of two compounds was followed by a powder X-ray diffraction test. The tested bioactive compounds were found to co-crystallize successfully with the peptide when they possessed both a hydrophobic part and strong hydrogen-bonding functionality. They were primarily derivatives of benzene, phenol, pyridine, pyrazine, quinoline and isoquinoline. Nearly all compounds with an amine or amide group formed a co-crystal, whereas most carboxylic acids did not form a new phase. For the successful combinations, single crystals were obtained when possible and studied using the single-crystal X-ray diffraction analysis. To our surprise, many of the co-crystals formed contained more than the two intended components due to the incorporation of the organic solvent and/or water. For example, one of the co-crystals studied displayed a complex hydrogen bonding framework built by four types of molecules: LA, 8-quinolinecarboxylic acid, ethanol and water in a 1:0.5:0.5:0.5 ratio.
Theoretical and X-ray diffraction studies of organic photovoltaic compounds
Authors: Chouaih Abdelkader , Yahiaoui Salem , Benhalima Nadia , Boulakoud Manel , Rahmani Rachida , Hamzaoui Fodil
Published: November 2015

The electronic and structural properties of thiazolic ring derivatives were studied using density functional theory (DFT) and X-ray diffraction in terms of their application as organic semiconductor materials in photovoltaic devices. The B3LYP hybrid functional in combination with Pople type 6-31G(d) basis set with a polarization function was used in order to determine the optimized geometries and the electronic properties of the ground state, while transition energies and excited state properties were obtained from DFT with B3LYP/6-31G(d) calculation. The investigation of thiazolic derivatives formed by the arrangement of several monomeric units revealed that three-dimensional (3D) conjugated architectures present the best geometric and electronic characteristics for use as an organic semiconductor material. The highest occupied molecular orbital (HOMO) . lowest unoccupied molecular orbital (LUMO) energy gap was decreased in 3D structures that extend the absorption spectrum toward longer wavelengths, revealing a feasible intramolecular charge transfer process in these systems. All calculations in this work were performed using the Gaussian 03 W software package.
Adducts of Trimeric Perfluro-o-Phenylene Mercury with TTF or DTT
Authors: Castaneda Raul , Draguta Sergiu , Yakovenko Andrey , Fonari Marina , Timofeeva Tatiana
Published: November 2015

Since the discovery of metallic conductivity in the TTF-TCNQ complex, the charge transfer (CT) complex materials have been studied for such properties as semiconductivity or superconductivity. The synthesis of new CT materials using trimeric perfluoro-ortho-phenylene mercury (Hg3) as electron acceptor compound was done first by Haneline and Gabaï [1]. A series of studies of CT materials containing Hg3 and tetrathiafulvalene (TTF) or dithieno thiophene (DTT) as an electron donor compounds was carried out by different methods. Co-crystalzation with TTF gave a larger variety of co-crystals than with DTT, producing three polymorphs and one pseudo-polymorph. One pot crystal growth of TTF and Hg3 in a 1:1 mixture of solvents dichloromethane (DCM) and dichloroethane (DCA) has led to the formation of TTF polymorphs 1 and 2 with same 1:1 donor acceptor ratio [Hg3·TTF] as well a pseudopolymorph [Hg3·TTF·DCA] 3 that contains the solvent DCA in the asymmetric unit. Slow evaporation in a 1:1 mixture of dichloromethane and carbon disulfide was used to obtain the previously reported CT [(Hg3)2·TTF] (4)1. By slow evaporation as well in pure dichloromethane was obtained the CT material [Hg3·DTT·DCM] 5. All these five CT co-crystals contain mixed donor acceptor stacks, however only in 3, 4 and 5 these stacks are parallel to each other. In the packing of 1 and 2 these stacks are in herringbone arrangement. Polymorphs 1 and 2 differ in crystal shape and color. Contacts Hg···S shorter than the sum of the Van Der Walls radii were observed in the five CTs materials reported, however only 1, 2, 3, and 5 have extended short donor acceptor molecular associates. Moreover only 3, and 5 has these extended donor acceptor associates along one direction.
Covalent Assistance to Supramolecular Synthesis
Authors: Lemmerer Andreas , Madeley Lee , Smith Mark
Published: November 2015

The similarity of crystal engineering to organic synthesis has been noted by Desiraju and many concepts and strategies have been successfully transferred. We aim to combine the two fields of research into one new concept called "Covalent Assistance to Supramolecular Synthesis". The supramolecular reagent isonicotinic acid hydrazide (isoniazid) is a promising molecule in the supramolecular synthesis of multi-component molecular complexes (Lemmerer at al., 2010). Due to the covalent reaction of the carbohydrazide functional group with simple ketones and aldehydes, the hydrogen bonding functionality of isoniazid can be modified, where two of the hydrogen bond donors are replaced with hydrogen bonding "inert" hydrocarbons (Lemmerer et al., 2011). The "modifiers" bonded to the isoniazid then give a measure of control of the outcome of the supramolecular synthesis with various carboxylic acids depending on the identity and steric size of the modifier used. The steric size itself can be used to shield or to "mask" the remaining hydrogen bonding functionality of isoniazid such that common homomeric and heteromeric interactions are prevented from taking place.
Alkali Metal Intercalation in Curved Carbon Networks: X-Ray Structural Studies
Authors: Sumner Natalie , Spisak Sarah , Zabula Alexander , Filatov Alexander , Rogachev Andrey , Petrukhina Marina
Published: November 2015

The intercalation of alkali metal ions into carbon-based aromatic systems is of great interest in materials science due to the increased need for stable anode materials with high capacity of energy storage. Currently, graphite, a sp2-hybirdized carbon network, is the key anode component in rechargeable Li-ion batteries. Carbon allotropes with nonplanar π-surfaces, ranging from fullerenes to nanotubes, are now under investigation as prospective anode materials. The curved carbon networks of fullerenes and nanotubes are often modeled by open bowl-shaped polyaromatic hydrocarbons, such as the smallest curved fullerene fragment, corannulene (C20H10). One of the most fascinating properties of such bowl-shaped polyarenes and fullerenes is their ability to reversibly uptake and delocalize extra electrons upon multi-electron reduction without significant rearrangement and deformation of their carbon framework [1,2]. Notably, the anode material fabricated from corannulene shows a high reversible lithium capacity (602 mAh/g). This is almost twice as high as the theoretical capacity of the commonly used fully lithiated planar graphite material (LiC6, 372 mAh/g). In our work, we target the X-ray structural elucidation of metal intercalation patterns of carbon-rich curved polyarenes with light alkali metal ions, such as Li and Na, and compare those with extended planar polyaromatic systems. Recently, we expanded this study to the light alkaline earth metal, Mg, as its atomic radius is very close to that of Li. In addition, magnesium is cost effective and abundant, and thus presents great interest in the emerging energy storage technologies.
Hierarchical Construction of Versatile Diamondoid Porous Organic Salts (d-POS)
Authors: Tohnai Norimitsu , Yamamoto Atsushi , Hisaki Ichiro , Miyata Mikiji
Published: November 2015

Porous materials using organic molecules have attracted much attention due to their potential application such as gas absorption and so on. However, it is still difficult to construct porous structures from only simple organic molecules. Thus, we proposed a novel hierarchical method to construct porous structures. In this method, the first step is to build up molecular assemblies. These assemblies act to sustain porous structures with larger inclusion spaces. Then, the assemblies are accumulated by intermolecular interactions between assemblies to achieve both robustness and dynamics of the porous structures. We have previously reported organic salts composed of triphenylmethylamine (TPMA) and various sulfonic acid derivatives constructed unique molecular assemblies "supramolecular clusters" through cubic hydrogen-bonding networks. Here we demonstrate that TPMA and sulfonic acids having polyaromatic moieties give a new class of porous structures consisting of diamond networks, named as diamondoid porous organic salts (d-POSs). The supramolecular clusters are hierarchically accumulated by π–π interactions between the polyaromatic moieties to yield the d-POSs through formation of the diamond networks. Large steric hindrance of the clusters prevents the diamond networks from constructing highly interpenetrated structures, giving continuous open channels. It should be noted that the interpenetration degree of the diamond networks is controlled by tuning the bulkiness of the cluster with alteration of sulfonic acids.