Reversible Humidity-Driven Transformation of a Bimetallic {EuCo} Molecular Material: Structural, Sorption, and Photoluminescence Studies

Functional molecule-based solids built of metal complexes can reveal a great impact of external stimuli upon their optical, magnetic, electric, and mechanical properties. We report a novel molecular material, {[EuIII(H2O)3(pyrone)4][CoIII(CN)6]}·nH2O (1, n = 2; 2, n = 1), which was obtained by the self-assembly of Eu3+ and [Co(CN)6]3− ions in the presence of a small 2-pyrrolidinone (pyrone) ligand in an aqueous medium. The as-synthesized material, 1, consists of dinuclear cyanido-bridged {EuCo} molecules accompanied by two H-bonded water molecules. By lowering the relative humidity (RH) below 30% at room temperature, 1 undergoes a single-crystal-to-single-crystal transformation related to the partial removal of crystallization water molecules which results in the new crystalline phase, 2. Both 1 and 2 solvates exhibit pronounced EuIII-centered visible photoluminescence. However, they differ in the energy splitting of the main emission band of a 5D0 → 7F2 origin, and the emission lifetime, which is longer in the partially dehydrated 2. As the 1 ↔ 2 structural transformation can be repeatedly reversed by changing the RH value, the reported material shows a room-temperature switching of detailed luminescent features including the ratio between emission components and the emission lifetime values.

Chiral porous CN-bridged coordination polymer mimicking MOF-74 and showing magnetization photoswitching

The cyanide-bridged coordination polymer mimics the topology and porosity of MOF-74. It also shows additional highly desired functionalities: chirality and photomagnetic effect, which makes it a truly multifunctional molecular material.

Computational and data driven molecular material design assisted by low scaling quantum mechanics calculations and machine learning

Low scaling quantum mechanics calculations and machine learning can be employed to efficiently predict the molecular energies, forces, and optical and electrical properties of molecular materials and their aggregates.

A new molecular material as a dopant-free hole-transporting layer for stable perovskite solar cells

In this work, a new small molecular material, 9,9′-(pyrene-1,6-diyldimethylylidene)bis[N,N,N′,N′-tetrakis(4-methoxyphenyl)-9H-fluorene-2,7-diamine] (PFD), as a hole-transporting layer was designed for perovskite solar cells (PSCs).

Polariton assisted photoemission from a layered molecular material: Role of vibrational states and molecular absorption

The way molecules absorb, transfer, and emit light can be modified by coupling them to optical cavities. The extent of the modification is often defined by the cavity-molecule coupling strength,...

Thermal switches between delayed fluorescence and persistent phosphorescence based on a keto-BODIPY electron acceptor

A new type of twisted donor–acceptor molecular material 3a and 3b containing carbazole as an electron donor and keto-BODIPY bearing keto-isoindolinyl and pyridyl subunits as an acceptor has been prepared and characterized.

SEDIGISM-ATLASGAL: dense gas fraction and star formation efficiency across the Galactic disc

ABSTRACT By combining two surveys covering a large fraction of the molecular material in the Galactic disc, we investigate the role spiral arms play in the star formation process. We have matched clumps identified by APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) with their parental giant molecular clouds (GMCs) as identified by SEDIGISM, and use these GMC masses, the bolometric luminosities, and integrated clump masses obtained in a concurrent paper to estimate the dense gas fractions (DGFgmc = ∑Mclump/Mgmc) and the instantaneous star formation efficiencies (i.e. SFEgmc = ∑Lclump/Mgmc). We find that the molecular material associated with ATLASGAL clumps is concentrated in the spiral arms (∼60 per cent found within ±10 $\rm {km\,s}^{-1}$ of an arm). We have searched for variations in the values of these physical parameters with respect to their proximity to the spiral arms, but find no evidence for any enhancement that might be attributable to the spiral arms. The combined results from a number of similar studies based on different surveys indicate that, while spiral-arm location plays a role in cloud formation and H i to H2 conversion, the subsequent star formation processes appear to depend more on local environment effects. This leads us to conclude that the enhanced star formation activity seen towards the spiral arms is the result of source crowding rather than the consequence of any physical process.

In smell’s shadow: Materials and politics at the edge of perception

This article examines the politics of smell at the edge of perception. In January 2014, the municipal water supply of Charleston, West Virginia was contaminated by an under-characterized chemical, crude MCHM. Even when instrumental measurements no longer detected the chemical, people continued to smell its licorice-like odor. In a space where nothing was certain, smell became the only indicator of potential harm. Officials responded by commissioning state-funded sensory testing of crude MCHM to determine its sensory threshold. Via the critical passage point of sensory science, some instances of embodied attunement were allowed to enter into the evidentiary regimes of perception, while other, similarly trained moments of attunement were excluded from the process. This, I show, produced knowledge about the spilled chemical that maintained the systems that contributed to the spill in the first place. Drawing on new materialist thought, I riff on biology and ‘transduce’ the ephemeral phenomena of smelling crude MCHM into a new medium: Rather than thinking of smell as a volatile molecular material (an odorant), I show that consideration of smell as a manipulable object that one can imagine as having tangible substance and shape offers a way to experiment with disciplinary forms. I suggest an alternate future, where sensory science acts to record sensory labor that produces facts about collective experience that cannot (easily) travel through current systems, a process that is one possible way of beginning to unravel entrenched systems of toxic harm.