The search for hydrogen-storage materials has been extremelly vivid during the recent decades, with those having high gravimetric contents of hydrogen being at the focus of the research. Among them, borohydrides show record high gravimetric H content reaching 21 wt.%. To taylor their thermodynamic stability, multi-cation light metal borohydrides have been explored in recent years. Crystal structure of these compounds are very dificult to charactererize from experiment due to low crystallinity, presence of poorly scattering atoms and frequent substitutional disorder. On the theoretical grounds these crystalline compounds have been modelled using Density Functional Theory (DFT) [1]. Here we demonstrate that classical DFT functionals are insuffecient for their descritpion and that weak dispersive H...H interactions must be taken to account to reach qualititave agreement with experiment. We present our findings on an important case of LiSc(BH₄)₄ containing ca. 14.4 wt% H, for which we solve old-standing problem of identifying the most stable polymorphic α form [2] and also resolve the identity of the recently reported β form [3]. Our findigs are based on systematic DFT/DFT-D3 study combined with lattice dynamics in quasiharmonic approximation (direct phonon method) and utilizing the Zr(BH₄)₄ structure models with Sc → Zr substation and Li filing the interstiticals  [4].

Acknowledgement: This research was carried out with the support of the Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw under grant no. ADVANCE++ (GA76-19). M.D. acknowledges the European Regional Development Fund, Research and Innovation Operational Programme, for project No. ITMS2014+: 313011W085 and Scientific Grant Agency of the Slovak Republic, grant No. VG 1/0223/19. The authors acknowledge the support from Polish National Science Centre under grant HYDRA no. 2014/15/B/ST5/05012.

References:

[1] C. Kim, S.-J. Hwang, R. C. Bowman, Jr., J. W. Reiter, J. A. Zan, J. G. Kulleck, H. Kabbour, E. H. Majzoub and V. Ozolins, J. Phys. Chem. C, 113, 9956 (2009).

[2] H. Hagemann, M. Longhini, J. W. Kaminski, T. A. Wesolowski, R. Černý, N. Penin, M. H. Sørby, B. C. Hauback, G. Severa and C. M. Jensen, J. Phys. Chem. A, 112, 7551 (2008).

[3] A. Starobrat, T. Jaroń, W. Grochala, Dalton Trans., 47, 4442 (2018).

[4] A. Starobrat, M. Derzsi, T. Jaroń, P. Malinowski and W. Grochala, available at https://arxiv.org (2020).

4(3H)-quinazolinone may act as ligand for metal ions in different coordination modes – coordinating through nitrogen atom para to the quinazolinone oxygen atom (mode 1), or through nitrogen atom ortho to the quinazolinone oxygen atom (mode 2), after hydrogen atom migration (tautomerization). Earlier crystal structural investigations have shown that in the reaction of cadmium chloride or bromide with 4(3H)-quinazolinone, this ligand interacts with Cd(II) cations via para nitrogen atoms (mode 1), and the octahedral coordination around the metal is completed by two ligands in a trans axial geometry. New cadmium(II) and mercury(II) coordination polymers were obtained via reaction of (3H)-quinazolinone with CdBr₂ and HgCl₂, respectively. Single crystal X-ray structural analysis reveals that coordination compounds crystallize in monoclinic P2₁/c and triclinic P-1 space groups, featuring halide-bridged 1D chain polymers based on momonuclear [M(X₂)(L)] subunits ((M = Cd, Hg, X = halide ion and L = 4(3H)-quinazolinone). Each metal ion is coordinated to one quinazolinone ligand, via the nitrogen atom ortho to the quinazolinone oxygen atom, with similar coordination geometries for metal ions in both coordination polymers.

Lyotropic liquid crystals (LCs) seem to play a significant role in biological systems. The well-known example of this material is DNA, that tends to self-organize into various lyotropic mesophases at high concentration water solutions [1]. Previous studies indicated that gold nanoparticles show different arrangement in DNA LCs. It was observed that elongated nanoparticles accumulate in the whole volume of the mesophase, while nanoclusters tend to aggregate on the top of the mesophase [2-3].

In the present work, mini gold nanorods (GNRs) have been chosen due to their strong photothermal efficiency [4]. The formation of DNA LCs doped with mini GNRs was investigated and compared with pure DNA LCs by polarized light microscopy. Furthermore, two-photon microscopy was used to image the distribution of mini GNRs in the DNA LC matrix. These systems could potentially be useful as models of interactions of NRs with DNA for biomedical applications such as cancer thermotherapy, owing to the large absorption cross-sections of mini GNRs. Moreover, mini GNRs exhibit higher cellular uptake (especially in tumor changed tissues) and lower cytotoxicity both in vitro and in vivo [5]. Reliable and reproducible protocols describing the synthesis of mini GNRs with well-defined plasmonic and optical properties predestine them as model materials for such investigations.

References

[1] Phys. Rev. Lett., 2006, 96, 177801

[2] Nanoscale, 2013, 5, 10975

[3] Langmuir, 2017, 33, 36, 8993–8999

[4] Chem. Mater., 2018, 30, 4, 1427–1435

[5] ACS Biomater. Sci. Eng., 2016, 2, 5, 789 –797

Magnesium ammonium phosphate hexahydrate, NH₄MgPO₄·6H₂O, known as struvite, has been widely investigated over the last decade for several reasons.

Firstly, struvite can be a problem in sewage and wastewater treatment as it precipitates easily on specific locations, which may clog the system pipes. On the other hand, struvite is potential source of phosphorus, nitrogen and magnesium, and therefore it is the main compound recovered from wastewater and recycled as a useful P-N-Mg-containing fertilizer. Third and the most important reason for which struvite is examined is the fact that it constitutes the main component of the so-called infectious urinary stones.

The presented investigations combine theoretical and experimental research of properties of struvite, such as: elastic constants, in particular modules: Kirchhoff G, Young's E and bulk K. Theoretical calculations of the above properties were carried out by density functional methods. Such calculations are a challenge, because these methods are mainly developed for semiconductors in view of fast development of electronics. However, struvite is a dielectric crystal. Therefore, quantum-chemical calculations for struvite are innovative. In the presented work, we also present the experimental results of the measurement of Young's modulus by the nanoindentation method.

The knowledge of elastic properties of struvite may point the manner by which urinary stones interact with the mechanical stresses produced by extracorporeal shock-wave lithotripsy - one of the most frequently used procedures for treatment the urinary stones. The knowledge of this properties may be also important from the perspective of prevention of struvite deposition in sewage treatment plants.

In the presented work, we also compare the experimentally obtained value of Young's modulus with the calculated theoretical value and on this basis, we draw conclusions regarding reliability of the quantum-chemical methods applied to the dielectric material.

Acknowledgments: The calculations are performed using the PLATON project's infrastructure at Lodz University of Technology Computer Centre.

The study of phase transitions in organic crystals as a step to tunable modification of their physicochemical properties is in the center of modern crystal engineering approaches. Organic crystals with polyiodide anions and S,N-containing heterocycles, such as the substituted thiazolo(azino)quinolinium salts [1-3] open possibility for the design of wide row of nonlinear optical and semiconductor materials and serve as components of dye-sensitized solar cell devices. Variety of crystal structures, available for material engineering is due to their ability to form different types of non-covalent interactions with iodine participation. The methodology of the present work includes consistent analysis of X-Ray diffraction and Raman spectroscopy data accompanied by the results of periodic quantum-chemical calculations in order to reveal the changes in crystal packing, non-covalent interactions feature and spectral properties as a result of undergoing phase transition under non-ambient conditions. In the center of the present work is the case of two newly obtained crystal structures of substituted thia- and oxazinoquinolinium iodides with the typical I…I halogen bonds. Substituted thiazinoquinolinium monoiodide undergoes low-temperature phase transition with decrease of symmetry from P21/c to P-1 registered by X-Ray diffraction and Raman spectroscopy. The interpretation of the observed changes in the Raman spectra is made on the basis of theoretic spectra in low wavenumber region.

Acknowledgments: This work was supported by the Ministry of Science and High Education of the Russian Federation, FENU 2020-0019

1. Bartashevich E.V.; Yushina I.D.; Stash A.I.; Tsirelson V.G. Crystal Growth & Design, 2014, 14 (11), P. 5674-5684

2. Yushina I.D.; Kolesov B.A.; Bartashevich E.V. New Journal of Chemistry, 2015, 39 (8), P. 6163-6170

3. Yushina I.D., Tarasova N.M., Kim D.G., Sharutin V.V., Bartashevich E.V. Crystals, 2019, 9, P. 506.

To improve drug product quality, the size and shape of active pharmaceutical ingredient (API) crystals need to meet tight specifications, in part determined by downstream manufacturing requirements. Improved critical quality attributes may also lead to better solubilisation and bioavailability during drug product delivery. Milling-aided crystallisation is a practical means to reduce the mean particle size and aspect ratio to meet these requirements and to improve downstream manufacturability. Other methods to control crystal shape employ temperature cycling during solution state crystallisation, e.g. Direct Nucleation Control (DNC) may be used to alter the particle morphology and size distribution through successive heating-cooling cycles for dissolution and recrystallisation.

In this work, the process objective is to target uniformly sized, equant shaped crystals with enhanced bioavailability using DNC crystallisation, integrated with either external loop and in-situ wet-milling. Experiments were conducted using mefenamic acid in 2-butanol, starting with a benchmark case of batch crystallisation with a linear cooling profile. This allowed identification of suitable DNC set-points, which were then implemented using closed-loop feedback control, based on sensing the FBRM counts. DNC is shown to be capable of improving crystal shape, but additional control is added by applying wet-milling to reduce crystal size. Application of wet-milling, combined with DNC was effective in reducing the crystal size D₉₀ < 50 mm and reducing the aspect ratio.

The wet-milling approaches were compared in terms of cycle time and final crystal size and shape, by varying the wet-milling speed, with targeted counts specified for the DNC set-point. The external wet-mill aided DNC crystallisations reached a steady-state with reduced cycle time and improved crystal morphology, in comparison with in-situ wet-mill aided DNC processes.

Protein backbone conformation of human acetylcholinesterase (hAChE; EC 3.1.1.7) the key enzyme in cholinergic neurotransmission, observed in over 40 PDB deposited X-ray structures appears largely identical. An exception was found in hAChE covalently inhibited by the organophosphate (OP) paraoxon where ethoxy substituent of the diethylphosphorylated active serine (Ser203), unable to fit into limited size of the acyl pocket, distorts the acyl pocket loop by shifting its Cα backbone. This obstructs access into the active center gorge and restricts ability of nucleophilic antidotes to reactivate inhibited hAChE.

We have analyzed six recently released X-ray structures of hAChE covalently inhibited by a series of phosphoramidate OPs known as Novichoks, A-230, A-232 and A-234, with or without reactivating antidote HI6, bound reversibly. A large phosphoramido substituent, identical in all three Novichoks fills the choline binding site of inhibited hAChE tightly, while remaining methyl (A-230), methoxy (A-232) or ethoxy (A-234) substituents are directed to the acyl pocket. We have explored, using PACCT3 (Pairwise Alpha Carbon Comparison Tool, available from www.ZENODO.org) whether conformations of the acyl pocket loop or of other backbone domains shifted in three conjugated hAChEs. Furthermore, we explored whether reversible binding of HI6 influenced backbone conformations of three conjugates. Our findings indicate that unlike diethylphosphorylated conjugate, in spite of their larger size, conjugated Novichok OPs do not alter the acyl pocket and cause minimal shifts in protein conformation. Nevertheless, the whole Ser203 bound OP conjugate appears shifted by ~ 1.5 Å towards the choline binding site and away from the acyl pocket. Several smaller α-helix shifts will be discussed.

This research was supported by the CounterACT Program, National Institutes of Health Office of the Director (NIH OD), and the National Institute of Neurological Disorders and Stroke (NINDS), [Grant Numbers U01 NS083451 and R21 NS098998].

Commercial azodye photoalignment materials based on our development are now readily available [1]. Many new displays and photonics applications, have been proposed and demonstrated. In particular, the application of photoalignment to active optical elements in optical signal processing and communications is currently a hot topic in photonics research [2].

Photoalignment on azo-dyes developed by us possesses obvious advantages in comparison with the usually “rubbing” treatment of the substrates of liquid crystal display (LCD) cells. Possible benefits for using this technique include :

• Elimination of electrostatic charges and impurities as well as mechanical damage of the surface;
• A controllable pretilt angle and anchoring energy of the liquid crystal cell, as well as its high thermo and UV stability and ionic purity;
• Possibility to produce the structures with the required LC director alignment within the selected areas of the cell, thus allowing pixel dividing to enable new special LC device configurations for transflective, multi-domain, 3D and other new display types;
• Potential increase of manufacturing yield, especially in LCDs with active matrix addressing, where fine tiny pixels of a high resolution LCD screen are driven by thin film transistors on a silicone substrate;
• New advanced applications of LC in fiber communications, optical data processing, holography and other fields, where the traditional rubbing LC alignment is not possible due to the sophisticated geometry of LC cell and/or high spatial resolution of the processing system;
• Ability for efficient LC alignment on curved and flexible substrates;
• Manufacturing of new optical elements for LC technology, such as patterned polarizers and phase retarders, tunable optical filters, polarization non-sensitive optical lenses, with voltage controllable focal distance etc.

This technique of azodye photoalignment does not involve any photochemical or structural transformations of the molecules. As well the new photoaligning films are robust and possess rather good aligning properties such as anchoring energies and voltage holding ratios. They can be very useful for the new generation of the liquid crystals devices as well as in new photovoltaic, optoelectronic and photonic devices based on highly ordered thin organic layers. Examples of such applications are light emitted diodes (OLED), solar cells, optical data storage and holographic memory devices. The novel and highly ordered layer structures of organic molecules may exhibit certain physical properties, which are similar to the aligned LC layers.

[1] V. Chigrinov, A. Srivastava, H.S. Kwok, Azo-dye photoalignment materials, In a book “High Quality Liquid Crystal Displays and Smart Devices - Volume 2: Surface alignment, new technologies and smart device applications”. IET. 2019, 41-64. Stevenage, UK.

[2] Vladimir G. Chigrinov, Liquid Crystal Photonics, Nova Science Publishers, December 2014.

SUNBIM (Supramolecular and sUbmolecular Nano- and Biomaterials X-ray IMaging) is a computer suite of integrated programs which, through a user-friendly graphical interface, is able to perform a number of functions for (GI)SAXS-(GI)WAXS data analysis [1] such as: centering, q-scale calibration, two-dimensional to one-dimensional folding of small- and wide-angle X-ray scattering (SAXS/WAXS) data, also in grazing-incidence (GISAXS/GIWAXS); indexing of two-dimensional GISAXS frames and extraction of one-dimensional GISAXS profiles along specific cuts; quantitative scanning microscopy in absorption and SAXS contrast.

SUNBIM consists of five main programs:

(1) Calibration package, a set of functions allow one to find all of the geometrical parameters needed to extract a one-dimensional profile out of a two-dimensional image;

(2) Batch Script & 2D Mesh Composite, to prepare batch script files (ASCII files) to run a sequential acquisition of two-dimensional frames (in scanning mode) and to perform a composite of the as-collected two-dimensional SAXS frames into a single image;

(3) Single-scan (GI)SAXS and (GI)WAXS data analysis, to calibrate and fold the two-dimensional data, in order to extract relevant information from the experimental data and to fold 2D data into 1D profiles;

(4) Multi-scan SAXS and WAXS data analysis, to fold each two-dimensional frame of the mesh into a one-dimensional profile and extract scattering features of the sample with a multi-modal imaging approach;

(5) One-D Data Analysis Manager, a package that in addition to basic operations on one dimensional profiles (such as change of the plot representation from pixels to q, change from linear scale to logarithmic scale of the axes, choice of colors and plot thickness, inserting the legend, etc. as well as import, trigger, save and export plots) gives the possibility to denoise the folded profile and/or to deconvolute the primary beam angular divergence from the SAXS/WAXS profiles, particularly useful for a complete data analysis.

SUNBIM combines in the same package both originally developed algorithms (i.e denoising, beam centering etc.) and reliable methods documented in the literature (multi-modal imaging [2], GIXAXS three-dimensional frame indexing [3]).

New tools have been developed to enrich SUNBIM suite. The main novelty is the possibility to perform a deeper data reduction including dark current subtraction, background evaluation and subtraction, normalization of the SAXS intensity against the local sample thickness derived from absorption contrast maps.

The advances of the new release with respect to previous one include also an automatic background subtraction from the 1D profile of the azimuthal integration to enhance peak visibility at large scattering angles (WAXS), to correct geometric aberration for small sample-to-detector distance.

The previous release of the software has already been used successfully to analyse several nano-structured samples [4][5][6]. We are confident that the new features will allow a more correct and extensive analysis of the (GI)SAXS/(GI)WAXS data.

SUNBIM is developed in the MATLAB language and it is distributed free of charge to the academic user (downloadable after a valid registration from http://www.ba.ic.cnr.it/softwareic/sunbimweb/)

REFERENCES:

[1] D Siliqi, L De Caro, M Ladisa, F Scattarella, A Mazzone, D Altamura, T Sibillano, and C Giannini, Journal of Applied Crystallography, 49:1107–1114,2016.

[2] O Bunk, M Bech, T H Jensen, R Feidenhans’l, T Binderup, A Menzel and F Pfeiffer, New J. Phys. 2009, 11, 123016

[3] R Lazzari, J. Appl. Cryst. 35, 406 (2002).

[4] T Sibillano, A Terzi, L De Caro, M Ladisa, D Altamura, A Moliterni, R Lassandro, F Scattarella, D Siliqi, C Giannini, Crystals 2020, 10(4), 274

[5] L De Caro, C Giannini, R Lassandro, F Scattarella, T Sibillano, E Matricciani, G Fanti, Heritage 2019, 2(4), 2763-2783

[6] J M Montes-de-Oca-Ávalosa, D Altamura, R J Candal, F Scattarella, D Siliqi, C Giannini, M L Herrera, Food Research International 105, 2018

In the ab-initio indexing of powder diffraction, the unitcell parameters are determined from the values of d-spacings of reflections. From a Kikuchi map of electron backscattering diffraction (EBSD), the orientations of the corresponding reciprocal lattice vectors can be obtained, instead of the d-values. As fundamental tools for indexing analyses that can be commonly used in such different situations, we have recently developed the following.

(i) algorithm for error-stable Bravais lattice determination,
(ii) generalization of the de Wolff figure of merit for powder diffraction to higher-dimensional data, including EBSD images.
(iii) rules on forbidden hkl's that can be used even when the space group is not known.

In particular, handling of symmetries and observational error of experimental data are central topics in crystallography. We explain how indexing algorithms (including theoretical discussion such as (iii)) can be simplified by using (i). Our indexing software is now available on the web.

Powder diffraction: https://z-code.kek.jp/zrg/ (CONOGRAPH with graphic user interface)

EBSD: https://osdn.net/projects/ebsd-conograph/ (only command-line interface, upgrade is planned)