Order and disorder in (E)-[1-(biphenyl-4-yl)ethylidene]hydrazine: a structural, spectroscopic and theoretical study

2018 ◽  
Vol 74 (11) ◽  
pp. 1459-1468
Author(s):  
Xue-Jie Tan ◽  
Qing-Zhe Zhao ◽  
Kun Li ◽  
Yong-Ji Hu ◽  
Jing-Chao Zhang
Keyword(s):  
Rational Design ◽  
Fluorescence Spectra ◽  
Energy Surface ◽  
Full Range ◽  
Scanning Calorimetry ◽  
Data Set ◽  
X Ray ◽  
Order And Disorder ◽  
Experimental And Theoretical Studies

An unexpected global disorder (co-existing rotational disorder and glide disorder) has been observed during an X-ray investigation of the crystal structure of (E)-[1-(biphenyl-4-yl)ethylidene]hydrazine, C14H14N2, at room temperature. When the temperature decreases to 273 K, the disorder disappears, but the quality of the data set is low. The diffraction data were collected again at 110 K. Differential scanning calorimetry (DSC) analysis and polarizing-microscopy experiments, as well as a fourth set of single-crystal data collected at 283 K, proved that the order–disorder transformation occurs continuously. The analyses of these crystal structures and full-range relaxed potential energy surface scans showed that this kind of global disorder is not very difficult to achieve inside the crystal. Experimental and theoretical studiesviaUV–Vis and fluorescence spectra impart an understanding on the prediction methods of optical properties, which are essential for the rational design of biphenyl-based materials with pre-defined properties.

Optimization of Structure of Soft Block for Design of Adaptive Polyurethanes

2020 ◽  
Vol 869 ◽  
pp. 273-279
Author(s):  
Marina A. Gorbunova ◽  
Denis V. Anokhin ◽  
Valentina A. Lesnichaya ◽  
Alexander A. Grishchuk ◽  
Elmira R. Badamshina
Keyword(s):  
Mutual Influence ◽  
Glycol Adipate ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Conditions ◽  
Crystalline Domains ◽  
Kinetics Of

A synthesis of new di-and triblock polyurethane thermoplastic copolymers containing different mass ratio of two crystallizing blocks - poly (1,4-butylene glycol) adipate and poly-ε-caprolactone diols was developed. Using combination of danamometric analysis, IR-spectroscopy, differential scanning calorimetry and X-ray diffraction, the effect of the soft block composition and crystallization conditions on crystal structure and thermal behavior of the obtained polymers have been studied. For the triblock copolymers we have shown a possibility of control the kinetics of material hardening and final mechanical characteristics due to the mutual influence of polydiols during crystallization. In the result, the second crystallizing component allows to control amount, structure and quality of crystalline domains in polyurethanes by variation of crystallization conditions.

When dendrimers are not better – rational design of nanolayers for high-performance organic electronic devices

Nanoscale ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 4463-4470 ◽  
Author(s):  
Maxim A. Shcherbina ◽  
Oleg V. Borshchev ◽  
Alexandra P. Pleshkova ◽  
Sergei A. Ponomarenko ◽  
Sergei N. Chvalun
Keyword(s):  
High Performance ◽  
Rational Design ◽  
Electronic Devices ◽  
Carbosilane Dendrimers ◽  
Scanning Calorimetry ◽  
Organic Electronic Devices ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force

Several generations of carbosilane dendrimers with quaterthiophene end groups were studied by X-ray scattering, differential scanning calorimetry, polarizing optical and atomic force microscopy and molecular modelling.

scholarly journals Spin frequency evolution and pulse profile variations of the recently re-activated radio magnetar XTE J1810–197

2019 ◽  
Vol 488 (4) ◽  
pp. 5251-5258 ◽  
Author(s):  
L Levin ◽  
A G Lyne ◽  
G Desvignes ◽  
R P Eatough ◽  
R Karuppusamy ◽  
...  
Keyword(s):  
Full Range ◽  
Active Phase ◽  
Main Pulse ◽  
Pulse Profile ◽  
Data Set ◽  
X Ray ◽  
Quiet State ◽  
Pulse Component ◽  
Timing Properties ◽  
Radio Band

Abstract After spending almost a decade in a radio-quiet state, the Anomalous X-ray Pulsar XTE J1810–197 turned back on in early 2018 December. We have observed this radio magnetar at 1.5 GHz with nearly daily cadence since the first detection of radio re-activation on 2018 December 8. In this paper, we report on the current timing properties of XTE J1810–197 and find that the magnitude of the spin frequency derivative has increased by a factor of 2.6 over our 48-d data set. We compare our results with the spin-down evolution reported during its previous active phase in the radio band. We also present total intensity pulse profiles at five different observing frequencies between 1.5 and 8.4 GHz, collected with the Lovell and the Effelsberg telescopes. The profile evolution in our data set is less erratic than what was reported during the previous active phase, and can be seen varying smoothly between observations. Profiles observed immediately after the outburst show the presence of at least five cycles of a very stable ∼50 ms periodicity in the main pulse component that lasts for at least tens of days. This remarkable structure is seen across the full range of observing frequencies.

scholarly journals MeshAndCollect: an automated multi-crystal data-collection workflow for synchrotron macromolecular crystallography beamlines

2015 ◽  
Vol 71 (11) ◽  
pp. 2328-2343 ◽  
Author(s):  
Ulrich Zander ◽  
Gleb Bourenkov ◽  
Alexander N. Popov ◽  
Daniele de Sanctis ◽  
Olof Svensson ◽  
...  
Keyword(s):  
Hierarchical Cluster ◽  
Data Sets ◽  
Macromolecular Crystallography ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
Partial Data ◽  
Final Data ◽  
Dispersion Technique

Here, an automated procedure is described to identify the positions of many cryocooled crystals mounted on the same sample holder, to rapidly predict and rank their relative diffraction strengths and to collect partial X-ray diffraction data sets from as many of the crystals as desired. Subsequent hierarchical cluster analysis then allows the best combination of partial data sets, optimizing the quality of the final data set obtained. The results of applying the method developed to various systems and scenarios including the compilation of a complete data set from tiny crystals of the membrane protein bacteriorhodopsin and the collection of data sets for successful structure determination using the single-wavelength anomalous dispersion technique are also presented.

Global indicators of X-ray data quality

2001 ◽  
Vol 34 (2) ◽  
pp. 130-135 ◽  
Author(s):  
Manfred S. Weiss
Keyword(s):  
Data Quality ◽  
Diffraction Data ◽  
Optical Resolution ◽  
Data Set ◽  
X Ray ◽  
Global Indicators ◽  
Nominal Resolution

Global indicators of the quality of diffraction data are presented and discussed, and are evaluated in terms of their performance with respect to various tasks. Based on the results obtained, it is suggested that some of the conventional indicators still in use in the crystallographic community should be abandoned, such as the nominal resolutiondminor the mergingRfactorRmerge, and replaced by more objective and more meaningful numbers, such as the effective optical resolutiondeff,optand the redundancy-independent mergingRfactorRr.i.m.. Furthermore, it is recommended that the precision-indicating mergingRfactorRp.i.m.should be reported with every diffraction data set published, because it describes the precision of the averaged measurements, which are the quantities normally used in crystallography as observables.

scholarly journals Continuous Manufacture and Scale-Up of Theophylline-Nicotinamide Cocrystals

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 419
Author(s):  
Steven A. Ross ◽  
Andrew P. Hurt ◽  
Milan Antonijevic ◽  
Nicolaos Bouropoulos ◽  
Adam Ward ◽  
...  
Keyword(s):  
Scale Up ◽  
Physicochemical Characterization ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Accelerated Stability ◽  
Continuous Manufacture ◽  
Hot Melt

The aim of the study was the manufacturing and scale-up of theophylline-nicotinamide (THL-NIC) pharmaceutical cocrystals processed by hot-melt extrusion (HME). The barrel temperature profile, feed rate and screw speed were found to be the critical processing parameters with a residence time of approximately 47 s for the scaled-up batches. Physicochemical characterization using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction of bulk and extruded materials revealed the formation of high purity cocrystals (98.6%). The quality of THL-NIC remained unchanged under accelerated stability conditions.

Strategies for data collection on a CCD-diffractometer

2000 ◽  
Vol 215 (9) ◽  
Author(s):  
M. Bolte ◽  
S. Rühl
Keyword(s):  
Crystal Size ◽  
Organic Molecules ◽  
Data Set ◽  
Detector Resolution ◽  
Small Organic Molecules ◽  
X Ray ◽  
Detector Distance ◽  
Complete Set ◽  
Time Scan

The introduction of area detectors has led to a significant reduction of the time needed for measuring a complete set of X-ray reflections. The default parameters suggested by the manufacturer of the instrument lead to good results, but both the software and the hardware provide the possibility of varying numerous parameters in order to optimize the quality of the data set. The influence of parameters (measuring time, scan angle, crystal-to-detector distance, collimator radius, detector resolution, redundancy, crystal size and scan type) is determined and rated with regard to their importance for the quality of the data. The investigations were carried out on a Siemens (now Bruker AXS) CCD diffractometer on three small organic molecules, p-nitrobenzaldehyde diacetate [P2

Improved crystallographic data for graphite

2003 ◽  
Vol 18 (2) ◽  
pp. 150-154 ◽  
Author(s):  
J. Y. Howe ◽  
C. J. Rawn ◽  
L. E. Jones ◽  
H. Ow
Keyword(s):  
Powder Diffraction ◽  
Figure Of Merit ◽  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
Hexagonal Cell ◽  
Data Set ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

Powder diffraction pattern of SP-1 graphite has been obtained using synchrotron X-ray diffraction. Unit cell dimensions were calculated using a least-squares analysis that refined to a |Δ2θ°| of no more than 0.007. A hexagonal cell was determined with a space group of P63/mmc (194), a=2.4617(2) and c=6.7106 (4) Å. The Smith/Synder figure of merit is 167 based upon 11 peaks, which indicates that the quality of this data set is superior to the existing PDF card for graphite, 41-1487. It is also emphasized that the interlayer spacing of graphite should be 3.355(1) Å. Using GAS and EXPGUI codes, a new set of calculated powder diffraction data based upon the interlayer spacing of 3.555 Å is generated. A comparison with the current calculated card, 75-1621, has also been made.

scholarly journals Good riddance to bad government? Institutional performance voting in Swedish municipalities

2021 ◽  
pp. 1-26
Author(s):  
Rasmus Broms
Keyword(s):  
Full Range ◽  
Institutional Quality ◽  
Political Corruption ◽  
Institutional Performance ◽  
Data Set ◽  
Electoral Accountability ◽  
Growing Body ◽  
Limited Support ◽  
Audit Reports

Abstract Electoral accountability is widely considered to be an essential component for maintaining the quality of a polity’s institutions. Nevertheless, a growing body of research has found weak or limited support for the notion that voters punish political corruption, a central but partial aspect of institutional quality. In order to capture the full range of institutional dysfunction an electorate should be incentivised to punish, I further the concept of institutional performance voting, that is, voting on institutional quality as a whole. Using a novel data set on performance audit reports in Swedish municipalities between 2003 and 2014, I find that audit critique is associated with a statistically significant but substantively moderate electoral loss of about a percentage point for mayoral parties, while simultaneously associated with a 14 percentage point decrease in their probability of reelection.

scholarly journals Interactive visualization tools for the structural biologist

2013 ◽  
Vol 46 (5) ◽  
pp. 1518-1520 ◽  
Author(s):  
Benjamin T. Porebski ◽  
Bosco K. Ho ◽  
Ashley M. Buckle
Keyword(s):  
Structural Biology ◽  
Data Bank ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
Software Packages ◽  
Organizational Problem ◽  
Visualization Tools ◽  
Macintosh Operating System

In structural biology, management of a large number of Protein Data Bank (PDB) files and raw X-ray diffraction images often presents a major organizational problem. Existing software packages that manipulate these file types were not designed for these kinds of file-management tasks. This is typically encountered when browsing through a folder of hundreds of X-ray images, with the aim of rapidly inspecting the diffraction quality of a data set. To solve this problem, a useful functionality of the Macintosh operating system (OSX) has been exploited that allows custom visualization plugins to be attached to certain file types. Software plugins have been developed for diffraction images and PDB files, which in many scenarios can save considerable time and effort. The direct visualization of diffraction images and PDB structures in the file browser can be used to identify key files of interest simply by scrolling through a list of files.

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