A comparative study of the effect of high-pressure and low temperature on the crystal structure of lithium xanthinate hydrate.

The crystal structure of lithium xanthinate hydrate was studied by single crystal X-ray diffraction and Raman spectroscopy on cooling to 100 K and under compression to 5.3 GPa. A phase transition at ∼4 GPa is observed.

Relating solvatochromism and solvatomorphism in organic dyes using high pressure.

By using complementary experimental methods including in situ high-pressure single-crystal X-ray diffraction and UV-Vis spectroscopy, the intricate connection between solvatochromism and solvatomorphism has been elucidated in a recent publication [Sobczak & Katrusiak (2024). IUCrJ, 11, 528-537]. The connection was demonstrated for an important pigment - Reichardt's dye - with potential applications in nonlinear optoelectronics and molecular pressure sensor development.

A comparison of the isostructural [Co(NH)NO]XNO and [Co(NH)ONO]XNO, X = Cl or Br in relation to nitro-nitrito linkage isomerization and photomechanical effects.

A new photoactive cobalt coordination compound, [Co(NH)NO]BrNO (I), was obtained. Its crystal structure was shown to be isostructural with previously known [Co(NH)NO]ClNO (II) for which linkage isomerization accompanied with mechanical response of the crystal has been already reported. Single crystals of I are transformed into nitrito isomer [Co(NH)ONO]BrNO (III) on irradiation with blue light (λ = 465 nm) without being destroyed.

Structural changes in Rochelle salt on phase transitions revisited in a multi-temperature single-crystal X-ray diffraction study.

Phase transitions in Rochelle salt [sodium potassium L(+)-tartrate tetrahydrate] are revisited in a single-crystal X-ray diffraction multi-temperature study on cooling from 308 to 100 K across the high-temperature paraelectric (PE) ↔ ferroelectric ↔ low-temperature PE phase transition points. The results of structure refinement using three different models (a harmonic with and without disorder, and an anharmonic) were compared. The temperature dependencies of anisotropic displacement parameters (ADPs) and U, which can be calculated directly from ADPs, for the low-temperature PE phase indicate clearly the dynamic nature of disorder of the K1 atoms.

Elastic and piezoelectric properties of β-glycine - a quantum crystallography view on intermolecular interactions and a high-pressure phase transition.

The effect of hydrostatic compression on the elastic and electronic properties of β-glycine was studied using a quantum crystallography approach. The interrelations between the changes in the microscopic quantum pressure in the electronic continuum, macroscopic compressibility and piezoelectricity were considered. The geometries and energies of hydrogen bonds in the crystal structure of β-glycine were considered as functions of pressure before and after a phase transition into the β'-phase in relation to the mechanism of this phase transition.

Radiation damage as a source of information.

The structural strain induced by temperature (`phonon pressure') and radiation damage (`defect pressure') is not necessarily correlated because of different underlying structural mechanisms. Here synchrotron experiments may provide new and yet unexplored opportunities. A recent publication by McMonagle et al.

A high-pressure single-crystal X-ray diffraction study of potassium guaninate hydrate, K·CHNO·HO.

The crystal structure of potassium guaninate hydrate, K·CHNO·HO, was studied in the pressure range of 1 atm to 7.3 GPa by single-crystal diffraction using synchrotron radiation and a laboratory X-ray diffraction source. Structural strain was compared to that of the same salt hydrate on cooling, and in 2Na·CHNO·7HO under hydrostatic compression and on cooling.

Spiers Memorial Lecture: Mechanochemistry, tribochemistry, mechanical alloying - retrospect, achievements and challenges.

The paper presents a view on the achievements, challenges and prospects of mechanochemistry. The extensive reference list can serve as a good entry point to a plethora of mechanochemical literature.

Deletion Variants of Autotransporter from Psychrobacter cryohalolentis Increase Efficiency of FN3 Exposure on the Surface of Escherichia coli Cells.

The autotransporter AT877 from Psychrobacter cryohalolentis belongs to the family of outer membrane proteins containing N-terminal passenger and C-terminal translocator domains that form the basis for the design of display systems on the surface of bacterial cells. It was shown in our previous study that the passenger domain of AT877 can be replaced by the cold-active esterase EstPc or the tenth domain of fibronectin type III (Fn3). In order to increase efficiency of the Fn3 surface display in Escherichia coli cells, four deletion variants of the Fn877 hybrid autotransporter were obtained.

Crystallography relevant to Mars and Galilean icy moons: crystal behavior of kieserite-type monohydrate sulfates at extraterrestrial conditions down to 15 K.

Monohydrate sulfate kieserites ( SO·HO) and their solid solutions are essential constituents on the surface of Mars and most likely also on Galilean icy moons in our solar system. Phase stabilities of end-member representatives ( = Mg, Fe, Co, Ni) have been examined crystallographically using single-crystal X-ray diffraction at 1 bar and temperatures down to 15 K, by means of applying open He cryojet techniques at in-house laboratory instrumentation. All four representative phases show a comparable, highly anisotropic thermal expansion behavior with a remarkable negative thermal expansion along the monoclinic axis and a pronounced anisotropic expansion perpendicular to it.

Clathrate Hydrates of Organic Solvents as Auxiliary Intermediates in Pharmaceutical Research and Development: Improving Dissolution Behaviour of a New Anti-Tuberculosis Drug, Perchlozon.

There is an urgent need for new drugs to overcome the challenge of the ever-growing drug resistance towards tuberculosis. A new, highly efficient anti-tuberculosis drug, Perchlozone (thioureidoiminomethylpyridinium perchlorate, Pz), is only available in an oral dosage form, though injectable forms and inhalation solutions could be better alternatives, offering higher bioavailability. To produce such forms, nano- and micro-particles of APIs would need to be prepared as dispersions with carriers.

Relating Excited States to the Dynamics of Macroscopic Strain in Photoresponsive Crystals.

Exposure of a photoreactive single crystal to light with a wavelength offset from its absorption maximum can have two distinct effects. The first is the "direct" effect, wherein the excited state generated in individual chemical species is influenced. The second is the "indirect" effect, which describes the penetration of light into the crystal and hence the spatial propagation and completeness of transformation.

Charge density studies of multicentre two-electron bonding of an anion radical at non-ambient temperature and pressure.

The variation of charge density of two-electron multicentre bonding (pancake bonding) between semi-quinone radicals with pressure and temperature was studied on a salt of 5,6-di-chloro-2,3-di-cyano-semi-quinone radical anion (DDQ) with 4-cyano--methyl-pyridinium cation (4-CN) using the Transferable Aspheric Atom Model (TAAM) refinement. The pancake-bonded radical dimers are stacked by non-bonding π-interactions. With rising pressure, the covalent character of interactions between radicals increases, and above 2.

Tribochemistry, Mechanical Alloying, Mechanochemistry: What is in a Name?

Over the decades, the application of mechanical force to influence chemical reactions has been called by various names: mechanochemistry, tribochemistry, mechanical alloying, to name but a few. The evolution of these terms has largely mirrored the understanding of the field. But what is meant by these terms, why have they evolved, and does it really matter how a process is called? Which parameters should be defined to describe unambiguously the experimental conditions such that others can reproduce the results, or to allow a meaningful comparison between processes explored under different conditions? Can the information on the process be encoded in a clear, concise, and self-explanatory way? We address these questions in this Opinion contribution, which we hope will spark timely and constructive discussion across the international mechanochemical community.

State-of-the-Art of Eggshell Waste in Materials Science: Recent Advances in Catalysis, Pharmaceutical Applications, and Mechanochemistry.

Eggshell waste is among the most abundant waste materials coming from food processing technologies. Despite the unique properties that both its components (eggshell, ES, and eggshell membrane, ESM) possess, it is very often discarded without further use. This review article aims to summarize the recent reports utilizing eggshell waste for very diverse purposes, stressing the need to use a mechanochemical approach to broaden its applications.

A cocrystal of L-ascorbic acid with picolinic acid: the role of O-H...O, N-H...O and C-H...O hydrogen bonds and L-ascorbic acid conformation in structure stabilization.

A new 1:1 cocrystal (L-Asc-Pic) of L-ascorbic acid (vitamin C) with picolinic acid was prepared as a powder and as single crystals. The crystal structure was solved and refined from single-crystal X-ray diffraction (SCXRD) data collected at 293 (2) and 100 (2) K. The samples of the L-Asc-Pic cocrystal were characterized by elemental (HCNS) analysis and titrimetric methods, TG/DTG/DSC, and IR and Raman spectroscopy.

Pancake-bonding of semiquinone radicals under variable temperature and pressure conditions.

The effects of temperature (100-370 K) and pressure (0-6 GPa) on the non-localized two-electron multicentric covalent bonds (`pancake bonding') in closely bound radical dimers were studied using single-crystal X-ray diffraction on a 4-cyano-N-methylpyridinium salt of 5,6-dichloro-2,3-dicyanosemiquinone radical anion (DDQ) as the sample compound. On cooling, the anisotropic structural compression was accompanied by continuous changes in molecular stacking; the discontinuities in the changes in volume and b and c cell parameters suggest that a phase transition occurs between 210 and 240 K. At a pressure of 2.

Mechanically Responsive Crystals: Analysis of Macroscopic Strain Reveals "Hidden" Processes.

Mechanical response of single crystals to light, temperature, and/or force-an emerging platform for the development of new organic actuating materials for soft robotics-has recently been quantitatively described by a general and robust mathematical model ( . 2015 , 115 , 12440 - 12490 ). The model can be used to extract accurate activation energies and kinetics of solid-state chemical reactions simply by tracking the time-dependent bending of the crystal.