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In a novel two-stage crosslinking binder system, the chemical switch controlled crosslinking between PAA and PEI not only facilitates the lamination process but also leads to covalent crosslinking and much improved cycling performance.

Redoxmers or redox-active organic materials, are one critical component for nonaqueous redox flow batteries (RFBs), which hold high promise in enabling the time domain of the grid. While tuning redox potentials of redoxmers is a very effective way to enhance energy densities of NRFBs, those improvements often accompany accelerated kinetics of the charged species, undermining stability and cycling performance. Herein, a strategy for designing redoxmers with simultaneous improvements in redox potential and stability is proposed. Specifically, the redoxmer 1,4-di

Recent evidence indicates that niclosamide is an anti-cancer compound that is able to inhibit several signaling pathways. Although niclosamide has previously been identified by high-throughput screening platforms as a potential effective compound against several cancer types, no direct binding interactions with distinct biological molecule(s) has been established. The present study identifies key signal transduction mechanisms altered by niclosamide in ovarian cancer. Using affinity purification with a biotin-modified niclosamide derivative and mass spectrometry analysis, several RNA-binding proteins (RBPs) were identified. We chose the two RBPs, FXR1 and IGF2BP2, for further analysis. A significant correlation exists in which high-expression of FXR1 or IGF2BP2 is associated with reduced survival of ovarian cancer patients. Knockdown of FXR1 or IGF2BP2 in ovarian cancer cells resulted in significantly reduced cell viability, adhesion, and migration. Furthermore, FXR1 or IGF2BP2 deficient ovarian cancer cells exhibited reduced response to most doses of niclosamide showing greater cell viability than those with intact RBPs. These results suggest that FXR1 and IGF2BP2 are direct targets of niclosamide and could have critical activities that drive multiple oncogenic pathways in ovarian cancer.

Redoxmers are organic molecules that carry electric charge in flow batteries. In many instances, they consist of heteroaromatic moieties modified with appended groups to prevent stacking of the planar cores and increase solubility in liquid electrolytes. This higher solubility is desired as it potentially allows achieving greater energy density in the battery. However, the present synthetic strategies often yield bulky molecules with low molarity even when they are neat and still lower molarity in liquid solutions. Fortunately, there are exceptions to this rule. Here, we examine one well-studied redoxmer, 2,1,3-benzothiadiazole, which has solubility ∼5.7 M in acetonitrile at 25 °C. We show computationally and prove experimentally that the competition between two packing motifs, face-to-face π-stacking and random N-H bond piling, introduces frustration that confounds nucleation in crowded solutions. Our findings and examples from related systems suggest a complementary strategy for the molecular design of redoxmers for high energy density redox flow cells.

Redoxmers are electrochemically active organic molecules storing charge and energy in electrolyte fluids circulating through redox flow batteries (RFBs). Such molecules typically have solvent-repelling cores and solvent-attracting pendant groups introduced to increase solubility in liquid electrolytes. These two features can facilitate nanoscale aggregation of the redoxmer molecules in crowded solutions. In some cases, this aggregation leads to the emergence of continuous networks of solute molecules in contact, and the solution becomes microscopically heterogeneous. Here, we use small-angle X-ray scattering (SAXS) and molecular dynamics modeling to demonstrate formation of such networks and examine structural factors controlling this self-assembly. We also show that salt ions become excluded from these solute aggregates into small pockets of electrolytes, where these ions strongly associate. This confinement by exclusion is also likely to occur to charged redoxmer molecules in a "sea" of neutral precursors coexisting in the same solution. Here, we demonstrate that the decay lifetime of the confined charged molecules in such solutions can increase several fold compared to dilute solutions. We attribute this behavior to a "microreactor effect" on reverse reactions of the confined species during their decomposition.

Redoxmers are redox-active molecules that can store energy in electrolytes for redox flow batteries (RFBs), and their electrochemical properties are significantly affected by the choice of supporting electrolytes. Herein, we use 2,1,3-benzothiadiazole (BzNSN) as a model system to scrutinize the supporting electrolyte impact. By systemically varying the components of supporting salts, BzNSN not only shows substantial redox potential shifts but also exhibits varying electrochemical stabilities. Specifically, changing the size of cations can effectively alter the coordination between the supporting salt and BzNSN species. From Li+, Na+, K+, to NEt4+, the redox potential of BzNSN shifts negatively, from −1.63 V to −1.82 V vs. Ag/Ag+. Molecular dynamics and density functional theory simulations revealed that smaller cations, like Li+, are closer to the charged BzNSN when coordinated, implying stronger coordination, while larger cations, like K+ and NEt4+, are farther away. Interestingly, the large cation electrolytes also lead to much improved electrochemical stability, evidenced by the extraordinarily enhanced kinetic lifetime from electron paramagnetic resonance measurement. This study demonstrates the first example of tuning an anolyte redoxmer toward a concurrent improvement of lowered redox potentials AND enhanced calendar lives via solvation means, which is usually constrained by the thermodynamic–kinetic relation.

Redox flow batteries (RFBs), in which electric charge is stored in redox-active materials (redoxmer) dissolved in liquid electrolytes, show significant potential for grid-scale energy storage applications. Because of the liquid nature, RFBs feature remarkable flexibilities, including decoupled energy and power that is highly desired for adapting various scales of energy storage requirements. Aprotic organic solvents are extensively studied as they can significantly extend the electrochemical window, leading to higher cell voltage and energy density of RFBs. To that end, developing redoxmers with high solubility and stability in non-aqueous solvents are actively pursed in order to realize the full potentials. Inorganic-based redoxmer materials showed good cyclability in aqueous redox flow batteries. Designing non-aqueous compatible redoxmers based on traditional inorganic-based materials encounter critical technical and economic limitations such as low solubility, inferior electrochemical activity, and high cost. In this presentation, a ferrate(III) based low potential redoxmer (anolyte) will be discussed. The synthesized redoxmer showed high solubility in acetonitrile (>2 M) with redox potential of ~-1.36 V (vs Ag/Ag+) and deliver very stable cycling performance evidenced by the symmetric H-cell cycling. The design approach for non-aqueous compatible redoxmers based on traditional inorganic-based materials may represent a promising strategy for constructing high energy dense and stable RFBs.

We report a nontraditional synthesis of cyclopentafused-polycyclic aromatic hydrocarbon embedded ladder polymers using a palladium catalyzed cyclopentannulation polymerization followed by a cyclodehydrogenation reaction. Donor–acceptor type polymers containing a cyclopenta[hi]aceanthrylene acceptor groups can be synthesized by a palladium catalyzed copolymerization between 9,10-dibromoanthracene and a variety of bis(arylethynyl)arenes to give polymers with molecular weights (Mn) of 9–22 kDa. The bis(arylethynyl)arenes were composed of benzene, thiophene, or thieno[3,2-b]thiophene moieties, which provided access to a series of four donor–acceptor copolymers. The polymers were subjected to cyclodehydrogenation with FeCl3 to access rigid ladder type polymers with the conversion investigated by 13C NMR of isotopically labeled polymers. The ladder polymers possess broad UV–Vis absorptions and narrow optical band gaps of 1.17–1.29 eV and are p-type semiconductors in organic field effect transistors.

Isomerically pure 5,11-dibromo-2,8-dihexylanthra[2,3-b:76-b′]dithiophene, a brominated analog of anthracenedithiophene (ADT), was prepared and utilized for a palladium catalyzed cyclopentannulation reaction with 3,3′-dimethoxy-phenylacetylene to give cyclopentannulated ADT (CP-ADTs). A further Scholl cyclodehydrogenation reaction gave contorted aromatics with large splay angles, low optical gaps, and low LUMOs.

A series of reduced band gap donor–acceptor copolymers that contain electron accepting 1,2,6,7-tetra(4-dodecylphenyl)dicyclopenta[cd,jk]pyrene were prepared. The hydrocarbon acceptor relies on its cyclopenta-fused polycyclic aromatic hydrocarbon (CP-PAH) character to access a relatively reduced lowest unoccupied molecular orbital. The donor unit was varied between thiophene, bithiophene, and 1,4-diethynyl-2,5-bis(octyloxy)-benzene producing polymers with band gaps between 1.69–1.74 eV. The synthetic methodology as well as the optoelectronic properties of the donor–acceptor copolymers, including thin-film absorption and cyclic voltammetry, are presented.

We show that a new class of contorted polycyclic aromatic hydrocarbons (PAHs) containing five-membered rings can be prepared via a palladium-catalyzed cyclopentannulation followed by Scholl cyclodehydrogenation. The annulation chemistry can be accomplished between a di-arylethynylene and an appropriate aryl-dibromide to form 1,2,6,7-tetraarylcyclopenta[hi]aceanthrylenes and 1,2,6,7-tetraaryldicyclopenta[cd,jk]pyrenes. Scholl cyclodehydrogenation to close the externally fused aryl groups was accomplished only with properly arranged alkoxy substitutions and provides access to the pi-extended 2,7,13,18-tetraalkoxytetrabenzo[f,h,r,t]rubicenes and 2,7,13,18-tetraalkoxydibenzo[4,5:6,7]indeno[1,2,3-cd]dibenzo[4,5:6,7]indeno[1,2,3-jk]pyrenes. The final compounds each possess apparent [4]helicene-like arrangements with fused five-membered rings; however, only the 2,7,13,18-tetraalkoxytetrabenzo[f,h,r,t]rubicenes contort out of planarity owing to an additional [5]helicene like arrangement. Single crystal analysis of the contorted aromatic shows the PAHs stack in a lock-and-key like arrangement and pi-stack in a columnar arrangement. Solution-phase aggregation, as well as liquid crystalline mesophases, were found for derivatives with suitably attached solubilizing chains.

A one-step postpolymerization modification that converts three high bandgap poly(arylene ethynylene)s into low bandgap donor–acceptor copolymers is described. The strategy relies on a palladium-catalyzed cyclopentannulation reaction between the main-chain ethynylene functionality and a small molecule aryl bromide (6-bromo-1,2-dimethylaceanthrylene). The reaction installs new cyclopenta[hi]aceanthrylene electron-accepting groups between the electron rich arylenes along the polymer backbone. The modified polymers include poly(9,9-didodecyl-fluorene-2,7-ethynylene), poly(9-dodecyl-carbazole-2,7-ethynylene), and poly(2,5-dioctyloxyphenylene-1,4-ethynylene). The functionalization efficiency was evaluated via isotopic 13C labeling of the polymeric ethynylene carbons and then monitoring the chemical environment of those carbons via NMR spectroscopy. Near complete conversion of the sp carbon species to sp2 carbon species was observed, which demonstrates the high efficiency of the modification strategy. Gel permea...

A new class of stabilized pentacene derivatives with externally fused five-membered rings are prepared by means of a key palladium-catalyzed cyclopentannulation step. The target compounds are synthesized by chemical manipulation of a partially saturated 6,13-dibromopentacene precursor that can be fully aromatized in a final step through a DDQ-mediated dehydrogenation reaction (DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone). The new 1,2,8,9-tetraaryldicyclopenta[fg,qr]pentacene derivatives have narrow energy gaps of circa 1.2 eV and behave as strong electron acceptors with lowest unoccupied molecular orbital energies between −3.81 and −3.90 eV. Photodegradation studies reveal the new compounds are more photostable than 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene).