Search

Dithieno[3,2‐b:2',3'‐d]thiophene (DTT) derivative contains three annulated thiophene rings, which have attracted great attention in the field of materials due to its planar and conjugated molecular, structural rigidity, and increased solubility. Herein, the one‐step modular construction of a series of structurally well‐defined 2,6‐disubstituted dithieno[3,2‐b:2',3'‐d]thiophenes (2,6‐DTT) involves Pd/Cu(I)‐catalyzed Sonogashira coupling and LiNH2‐mediated ring‐closing reaction with element sulfur was reported. The method allows the selective and straightforward introduction of different aryl substitution into DTT without otherwise tedious separation and purification processes. The preliminary study of the thermal and photophysical properties demonstrated that the introduction of substituent in phenyl has great impact for the parent molecule, which enable this protocol to synthesis high‐performance 2,6‐DTT through the different alkynes. [ABSTRACT FROM AUTHOR]

Designing a multifunctional electrocatalyst to produce H2 from water, urea, urine, and wastewater, is highly desirable yet challenging because it demands precise Fermi‐engineering to realize stronger π‐donation from O 2p to electron(e−)‐deficient metal (t2g) d‐orbitals. Here a Sr‐induced phase transformed β‐FeOOH/α‐Ni(OH)2 catalyst anchored on Ni‐foam (designated as pt‐NFS) is introduced, where Sr produces plenteous Fe4+ (Fe3+ → Fe4+) to modulate Fermi level and e−‐transfer from e–‐rich Ni3+(t2g)‐orbitals to e–‐deficient Fe4+(t2g)‐orbitals, via strong π‐donation from the π‐symmetry lone‐pair of O bridge. pt‐NFS utilizes Fe‐sites near the Sr‐atom to break the H─O─H bonds and weakens the adsorption of *O while strengthening that of *OOH, toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Invaluably, Fe‐sites of pt‐NFS activate H2‐production from urea oxidation reaction (UOR) through a one‐stage pathway which, unlike conventional two‐stage pathways with two NH3‐molecules, involves only one NH3‐molecule. Owing to more suitable kinetic energetics, pt‐NFS requires 133 mV (negative potential shift), 193 mV, ≈1.352 V, and ≈1.375 V versus RHE for HER, OER, UOR, and human urine oxidation, respectively, to reach the benchmark 10 mA cm−2 and also demonstrates remarkable durability of over 25 h. This work opens a new corridor to design multifunctional electrocatalysts with precise Fermi engineering through d‐band modulation. [ABSTRACT FROM AUTHOR]

Li2CO3 is the most tenacious parasitic solid-state product in lithium–air batteries (LABs). Developing suitable redox mediators (RMs) is an efficient way to address the Li2CO3 issue, but only a few RMs have been investigated to date, and their mechanism of action also remains elusive. Herein, we investigate the effects of the central metal ion in binuclear metal phthalocyanines on the catalysis of Li2CO3 decomposition, namely binuclear cobalt phthalocyanine (bi-CoPc) and binuclear cobalt manganese phthalocyanine (bi-CoMnPc). Density functional theory (DFT) calculations indicate that the key intermediate peroxydicarbonate (*C2O62−) is stabilized by bi-CoPc2+ and bi-CoMnPc3+, which is accountable for their excellent catalytic effects. With one central metal ion substituted by manganese for cobalt, the bi-CoMnPc's second active redox couple shifts from the second Co(II)/Co(III) couple in the central metal ion to the Pc(-2)/Pc(-1) couple in the phthalocyanine ring. In artificial dry air (N2-O2, 78:22, v/v), the LAB cell with bi-CoMnPc in electrolyte exhibited 261 cycles under a fixed capacity of 500 mAh g−1carbon and current density of 100 mA g−1carbon, significantly better than the RM-free cell (62 cycles) and the cell with bi-CoPc (193 cycles). [ABSTRACT FROM AUTHOR]

We bootstrap the 4-point amplitude of N = 2 hypermultiplets in AdS2 × S2 at tree-level and for arbitrary external weights. We hereby explicitly demonstrate the existence of a hidden four-dimensional conformal symmetry that was used as an assumption in previous studies to derive this result. [ABSTRACT FROM AUTHOR]

A novel method to prepare asymmetric amine ethers is reported. Tertiary amine alcohol hydrogen sulfate intermediates are prepared through a reactive distillation process, followed by the transesterification process to afford eventually asymmetric amine ethers. Experiments and DFT calculations revealed the essential roles the sulfate group plays in the highly selective monoesterification process. This clean method is tolerant towards various functional groups with good yields under mild condition, which is obviously superior compared to the conventional processes. [ABSTRACT FROM AUTHOR]