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Here we report on a scanning tunnelling microscopy (STM) investigation on the self-assembly of C 3 - and C 2 -symmetric molecules at the solution/graphite interface. 1,3,5-tris(( E )-2-(pyridin-4-yl)vinyl)benzene and 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethane are used as model systems. These molecules displayed a concentration dependent self-assembly behaviour on graphite, resulting in highly ordered supramolecular structures, which are stabilized jointly by van der Waals substrate-adsorbate interactions and in-plane intermolecular H-bonding. Denser packing is obtained when applying a relatively high concentration solution to the basal plane of the surface whereas a less dense porous network is observed upon lowering the concentration. We show that the molecular conformation does not influence the stability of the self-assembly and a twisted molecule can pack into dense and porous architectures under the concentration effect. [ABSTRACT FROM AUTHOR]

Non-aqueous redox flow batteries (naRFBs) are promising candidates as high-capacity energy storage devices. Although the wide redox windows associated with the organic solvents used in naRFBs are useful to realize high open circuit voltages, the low solubilities of electrolytes often minimize the energy densities. Strategies have emerged to increase the concentration of active materials employed in naRFBs; however, the dilute conditions typically associated with chronoamperometry and voltammetric experiments are orders of magnitude lower than those found in a working RFB. The electrochemical behavior of non-aqueous electrolytes may differ at high concentrations due to changes in solvation structure, aggregation, solution resistance, and mass transport, which in turn affect the overall cell performance. Accordingly, we studied a series of naRFB systems using ferrocene/TEMPO as a posolyte, and cobaltocenium hexafluorophosphate/N-methylphthalimide as a negolyte, to investigate the effect of concentration on charge-discharge profiles. Cycling studies were performed with four combinations of the above-mentioned catholyte and anolyte materials. Concentration regimes were explored ranging from 10 mM to 1 M depending on the maximum solubility of a given active species. The results indicate that cycling behaviors are concentration dependent. Coulombic efficiencies and voltage efficiencies are calculated for each system. In addition, it was observed that the specific combination of catholyte/anolyte also affects the charge-discharge profiles and that membrane crossover and fouling is a major contributor to performance losses. [ABSTRACT FROM AUTHOR]

[Display omitted] • A pioneering example of incorporating [CB 11 H 12 ]- into Platinum triplet emitters. • Anionic [CB 11 H 12 ]- enforced the charge neutrality of cationic Platinum emitter. • Anionic [CB 11 H 12 ]- optimized the Platinum emitter PLQY from 54% to 97%. • OLEDs exhibited green electroluminescence with CIE coordinates of (0.28, 0.55). • OLEDs exhibited the maximum external quantum efficiency (EQE max) of 18.51%. The use of organometallic triplet emitters in OLED applications may be complicated when the luminescent complex bears a formal charge. By designing ligands containing pendant closo -monocarborane clusters [CB 11 H 11 ]−, it is possible to neutralize the otherwise cationic cores of cyclometalated Pt(II) complexes bearing bis -carbenes, resulting in significantly enhanced photophysical properties. Herein, we report four Pt(II) complexes decorated with a monoanionic closo -monocarborane by coupling the cluster to the classic cyclometallating moiety, phenylpyridine (ppy). All four complexes were fully characterized by NMR, HR-MS, UV–Vis, and cyclic voltammetry. Complexes 1b , 1c and 2a were characterized by single-crystal X-ray diffraction. Moreover, all four complexes show interesting photophysical behaviors, with complex 1a exhibiting a photoluminescent quantum yield of 97% in a 2 wt% PMMA film. This high efficiency prompted the incorporation of 1a and 1c into an OLED device using solution processing, resulting in green emission with CIE coordinates of (0.28, 0.55) for 1a and yellow emission with CIE coordinates of (0.44, 0.50) for 1c. The measured maximum external quantum efficiency (EQE max) was 18.51% for 1a , an EQE max that is among the highest for solution-processed OLED devices containing Pt(II) complexes with simple cyclometalated ppy ligands. [ABSTRACT FROM AUTHOR]

Mixed matrix materials (MMMs) comprising porous fillers in polymers can exhibit superior gas separation properties, yet their practical use has been limited by poor interfacial compatibility between the two components. Herein we report a bottom-up approach to synthesize the MMMs by dispersing a metal-organic polyhedron (MOP-3) in monomer solutions before rapid photopolymerization to form interpenetrating networks (IPNs), where the porous MOP-3 nanoparticles serve as molecular dopants. Specifically, MOP-3 with particle sizes of ≈5 nm was dispersed in and infiltrated by either a macromonomer of poly(ethylene glycol) diacrylate (PEGDA) or poly(1,3 dioxolane) acrylate (PDXLA). The introduction of the MOP-3 in the polyethers decreases their glass transition temperatures and even induces the crystallization of polyPDXLA at high loadings. Increasing the MOP loading increases CO 2 permeability with a slight decrease in CO 2 /gas selectivity. For example, as the MOP content increases from 0 to 30 mass% in polyPDXLA, CO 2 permeability increases from 190 Barrer to 580 Barrer, and CO 2 /N 2 selectivity decreases from 70 to 62 at 35 °C. These IPNs-based MMMs exhibit separation properties above the Robeson's upper bounds for CO 2 /N 2 and CO 2 /H 2 separation. As the MOPs are soluble in solvents, this approach can be easily integrated into industrial membrane fabrication processes to produce MMMs-based composite membranes in large-scale. Image 1 • Metal-organic polyhedra (MOP-3) was dispersed in monomers before polymerization. • Adding MOP-3 (<5 nm) in polyethers increases chain flexibility and decreases T g. • Increasing MOP-3 loadings enhances permeability and retains CO 2 /gas selectivity. • Adding 2% MOP-3 increases gas permeability by more than 100%. • MOP-3 can be dissolved in coating solutions for large-scale membrane fabrication. [ABSTRACT FROM AUTHOR]