Structural Investigation of Di-μ-chloro-bis[saccharinatopyridinemercury(II)] by X-ray Diffraction and FT IR Spectroscopy

The solid state structure of C12H9ClHgN2O3S2 was determined and the appropriate assignment of the CO and SO2 stretching vibrations in the FT IR spectrum was made. Two monomeric chlorosaccharinatopyridinemercury(II) moieties are joined together forming a di-chloro bridged dimmer by an inversion centre operation. The mercury atom is coordinated with two bridging chlorine and the pyridine and saccharinato nitrogen atoms in the shape of a heavily distorted tetrahedron. There is a significant difference between Hg1–Cl1 2.533(2) Å and Hg1–Cl1i 2.715(2) Å distances as well as between Hg1–N11 2.106(7) Å and Hg1–N21 2.209(7) Å bond lengths. The valence bond angles at the metal atom deviate significantly from the standard tetrahedral value, ranging from 86.23(7)° for Cl1–Hg1–Cl1i to 131.5(3)° for N11–Hg1–N21. Discrete molecules are linked together by weak intermolecular C–H⋅⋅⋅O attractions at distances less than 3.5 Å

Novel gold(I) diphosphine-based dimers with aurophilicity triggered multistimuli light-emitting properties

We report a design strategy for the preparation of stimuli-responsive materials with multicolour emission that is based on a single type of luminophore molecule comprising gold(i) and a flexible diphosphine ligand.</p

Photomechanical and Photochromic Behavior of a Molecule Containing Multiple Photoactive Groups

Photomechanical and photochromic activities are reported for single crystals of a new multirespon-sive material, 2,4-di-tert-butyl-6-((E)-((4-((E)-phenyldiazenyl)phenyl)imino)methyl)phenol (Azim-1), with two photoactive groups that can undergo photoisomerization (azo and imine), and an ortho-hydroxy group that is capable of proton transfer. Upon irradiation with UV light, platy and needle-shaped crystals of Azim-1 rapidly bend towards the light source and return to their initial shape as soon as the irradiation is terminated. Upon prolonged exposure to UV light, the crystals change their color from yellow to red. The crystal structure of non-irradiated Azim-1 is reported, and the mecha-nisms of the photomechanical and photochromic responses are discussed

Fine-tuning of a thermosalient phase transition by solid solutions

Thermosalient crystals are solids that exhibit motion at the macroscale as a consequence of a thermally induced phase transition. They represent an interesting scientific phenomenon and could be useful as actuators for the conversion of thermal energy into motion or mechanical work. The potential utilization of these miniature transducers in real-world devices requires a controllable phase transition (i.e. a predetermined temperature). While it is difficult to control these performances with a single-component molecular crystal, “tunable” properties could be accomplished by solid solutions. To verify this hypothesis, the thermosalient material [Zn(bpy)Br2] (bpy = 2,2′-bipyridine) was selected and its synthesis was performed in the presence of chloride ions. The resulting mixed crystals ([Zn(bpy)Br2xCl2(1−x)]) show that the product undergoes the expected thermosalient phase transition, and the temperature of the onset of the phase transition and the transition enthalpy depend on the Cl/Br ratio

Charting a course for chemistry

To mark the occasion of Nature Chemistry turning 10 years old, we asked scientists working in different areas of chemistry to tell us what they thought the most exciting, interesting or challenging aspects related to the development of their main field of research will be — here is what they said

Acoustic Emission from Organic Martensites

In salient effects, still crystals of solids that switch between phases acquire a momentum and are autonomously propelled because of rapid release of elastic energy accrued during a latent structural transition induced by heat, light, or mechanical stimulation. When mechanical reconfiguration is induced by change of temperature in thermosalient crystals, bursts of detectable acoustic waves are generated prior to self-actuation. These observations provide compelling evidence that the thermosalient transitions in organic and organic-containing crystals are molecular analogues of the martensitic transitions in some metals, and metal alloys such as steel and shape-memory alloys. Within a broader context, these results reveal that, akin to metallic bonding, the intermolecular interactions in molecular solids are capable of gradual accrual and sudden release of a substantial amount of strain during anisotropic thermal expansion, followed by a rapid transformation of the crystal packing in a diffusionless, non-displacive transition

Templated deposition of porous fullerene-C 60

The unique set of mechanical properties found in rigid biological tissues, which combine high strength and stiffness with superior toughness, offer inspiration for the design of advanced functional structural materials with outstanding performance. This paper reports on the first utilization of one such biogenic material-siliceous sponge spicules, the skeletal elements of sponges (Poriphera)-as a unique naturally nanostructured template for vacuum deposition, while also reporting on the effects of the required chemical and thermal treatments for template preparation on the material's microstructure and mechanical properties. The confined space within the central channel of spicules from the sponge Euplectella acts simultaneously as a nanotemplate and as a biogenic, optically transparent, glassy microchamber for the preparation of micrometer-sized clusters of fullerene-C-60 through vacuum deposition onto the nanostructured surface. This biological material allows an unprecedented and unique microporous morphology of C-60 particles to be obtained

A stable gold(I)–enyne species obtained by alkyne carboauration in a complex rearrangement

An unprecedented tetranuclear gold derivative with unusual gold-enyne moieties is prepared by a mild and neat rearrangement of a dinuclear gold complex with a bridging bis(diphenylphosphino)alkyne and terminal alkynyl ligands. The complex originates as a consequence of an intramolecular addition of the AuC[triple bond, length as m-dash]CTol fragment to the internal diphosphine triple bond Ph2PC[triple bond, length as m-dash]CPPh2. The crystal structure of the tetranuclear complex shows a dinuclear metallacycle with a very short Au⋯Au bond interaction and bridging phosphino–enyne ligands. This disposition clearly stabilises the elusive vinyl gold species omnipresent as intermediates in gold-catalysed reactions.Financial support was provided by the Ministerio de Economía y Competitividad-FEDER (CTQ2016-75816-C2-1-P) and Gobierno de Aragon-Fondo Social Europeo FSE (E77).Peer reviewe

Remote and precise control over morphology and motion of organic crystals by using magnetic field

Elastic organic crystals are the materials foundation of future lightweight flexible electronic, optical and sensing devices, yet precise control over their deformation has not been accomplished. Here, we report a general non-destructive approach to remote bending of organic crystals. Flexible organic crystals are coupled to magnetic nanoparticles to prepare hybrid actuating elements whose shape can be arbitrarily and precisely controlled simply by using magnetic field. The crystals are mechanically and chemically robust, and can be flexed precisely to a predetermined curvature with complete retention of their macroscopic integrity at least several thousand times in contactless mode, in air or in a liquid medium. These crystals are used as optical waveguides whose light output can be precisely and remotely controlled by using a permanent magnet. This approach expands the range of applications of flexible organic crystals beyond the known limitations with other methods for control of their shape, and opens prospects for their direct implementation in flexible devices such as sensors, emitters, and other (opto)electronics