Au@CuO Core-Shell and Au@CuSe Yolk-Shell Nanocrystals as Promising Photocatalysts in Photoelectrochemical Water Splitting and Photocatalytic Hydrogen Production.

In this work, we demonstrated the practical use of Au@CuO core-shell and Au@CuSe yolk-shell nanocrystals as photocatalysts in photoelectrochemical (PEC) water splitting and photocatalytic hydrogen (H) production. The samples were prepared by conducting a sequential ion-exchange reaction on a Au@CuO core-shell nanocrystal template. Au@CuO and Au@CuSe displayed enhanced charge separation as the Au core and yolk can attract photoexcited electrons from the CuO and CuSe shells.

Distinct Carrier Transport Properties Across Horizontally vs Vertically Oriented Heterostructures of 2D/3D Perovskites.

Two-dimensional-on-three-dimensional (2D/3D) halide perovskite heterostructures have been extensively utilized in optoelectronic devices. However, the labile nature of halide perovskites makes it difficult to form such heterostructures with well-defined compositions, orientations, and interfaces, which inhibits understanding of the carrier transfer properties across these heterostructures. Here, we report solution growth of both horizontally and vertically aligned 2D perovskite (PEA)PbBr (PEA = phenylethylammonium) microplates onto 3D CsPbBr single crystal thin films, with well-defined heterojunctions.

π-Extended Coumarins Derived with Nonhydrolyzable Iminophosphoranes as Two-Photon-Excited Fluorophores.

Novel coumarin-iminophosphorane (IPP) fluorophores that have stable resonance contributions from aza-ylides were formed by using the nonhydrolysis Staudinger reaction. The N═P formation reaction kinetics obey the conventional Staudinger reaction. The absorption and emission profiles of the coumarin-IPP derivatives can be fine-tuned: an electron-donating group at PPh enhances absorption and fluorescence, whereas an electron-withdrawing group at C-3 drives absorption and emission peaks toward blue-light wavelengths.

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitrile Derivatives for Air-Stable -Type Organic Field-Effect Transistors: Critical Role of -Alkyl Substituent on Device Performance.

Benzodipyrrole-2,6-dione-3,7-diylidenedimalononitriles (BDPMs) were synthesized as active materials for the use in air-stable -type organic field-effect transistors (OFETs), whose optical and electrochemical properties were examined. BDPM-based small molecules exhibit deep lowest unoccupied molecular orbital levels, which are required in air-stable -type OFETs. An OFET device that was based on and fabricated by vapor deposition provided a maximum electron mobility of 0.

Benzophenanthrothiophenes: Syntheses, Crystal Structures, and Properties.

A new class of polycyclic heteroarenes based on benzo[3,4]phenanthro[1,2-]benzo[3,4]phenanthro[2,1-]thiophene () was prepared from polyaryl thiophenes via regioselective Scholl reactions. The molecular frameworks of these compounds exhibited twisted bridges and near-cofacial packing motifs with oppositely or parallel π-stacked structures depending on the substituents on the periphery. Theoretical calculation of electronic coupling and charge mobility was carried out on the basis of the single-crystal structures.

In Situ Analysis of Growth Behaviors of CuO Nanocubes in Liquid Cell Transmission Electron Microscopy.

Metal oxides have attracted substantial attention over the years and are commonly used in the semiconductor industry because of their excellent physical and chemical properties. Among the various metal oxides, cuprous oxide (CuO) is regarded as a promising material. It is inexpensive, earth-abundant, and nontoxic; therefore, it can be used in catalysis, sensors, solar cells, and p-type semiconductors.

In situ TEM observation of Au-CuO core-shell growth in liquids.

Heterogeneous nanoparticles are widely used in catalysis, sensors and biology due to their versatile functions. Among the various heterogeneous nanoparticles, Au-Cu2O core-shell nanoparticles show high stability and short response times for use as sensors and catalysts and have thus attracted much attention. Previous studies show that the properties of Au-Cu2O are mainly related to the shape and size of the Au-Cu2O nanoparticles.

Angular-Shaped Naphthalene Bis(1,5-diamide-2,6-diylidene)malononitrile for High-Performance, Air-Stable N-Type Organic Field-Effect Transistors.

The synthesis, characterization, and application of two angular-shaped naphthalene bis(1,5-diamide-2,6-diylidene)malononitriles (NBAMs) as high-performance air-stable n-type organic field effect transistor (OFET) materials are reported. NBAM derivatives exhibit deep lowest-unoccupied molecular orbital (LUMO) levels, suitable for air-stable n-type OFETs. The OFET device based on NBAM-EH fabricated by vapor deposition exhibits a maximum electron mobility of 0.

Di-2-(2-oxindolin-3-ylidene)malononitrile Derivatives for N-Type Air-Stable Organic Field-Effect Transistors.

The nitrogenization of phenyl rings on DIM derivatives not only enhances molecular coplanarity but also stabilizes molecular LUMO levels, favoring charge transfer and improving air stability. Therefore, n-type organic field-effect transistors (OFETs) that are based on DIM-N2C8 with nitrogen atoms on both sides of the phenyl rings exhibit a moderate electron mobility of 0.059 cm V s under ambient conditions.

Effect of Imidazole on the Electrochemistry of Zinc Porphyrins: An Electrochemical and Computational Study.

In this study, the electrochemical behavior of zinc meso-substituted porphyrins in the presence of imidazole is examined by using both cyclic voltammetry (CV) and density functional theory (DFT) methods. The results show that the first half-wave oxidation potentials (1st E) of zinc porphyrins complexed with imidazole all move to the negative side, while the second ones (2nd E) move to the positive side, resulting in larger half-wave oxidation potential splittings of the two oxidation states (ΔE = second E - first E) comparing with the zinc porphyrins. By employing DFT calculations, we have found that both sterically controlled inter π-conjugation between porphyrin rings and meso-substituted phenyl groups and deformation of porphyrin rings do play important roles in contributing to the half-wave oxidation potentials.

Electrochemical Behavior of meso-Substituted Porphyrins: The Role of Cation Radicals to the Half-Wave Oxidation Potential Splitting.

In this study, the electrochemical behavior of free base and zinc meso-substituted porphyrins is examined by cyclic voltammetry (CV) and density functional theory (DFT). The results show that the half-wave oxidation potential splitting of the two oxidation states (ΔE= second E1/2 - first E1/2) of tetraphenylporphyrin (H2TPP) and its zinc complex (ZnTPP) are higher than those of porphyrins and their zinc complexes with meso-substituted five-membered heterocylic rings. The ΔE values follow the trend of TPP > T(3'-thienyl)P > T(3'-furyl)P > T(2'-thienyl)P for both meso-porphyrins and their respective zinc complexes.

Hexaazatrinaphthylene Derivatives: Efficient Electron-Transporting Materials with Tunable Energy Levels for Inverted Perovskite Solar Cells.

Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6 % with negligible hysteresis.

Per-Substituted [8]Circulene and Its Non-Planar Fragments: Synthesis, Structural Analysis, and Properties.

The syntheses, structures, and physical properties of a full series of benzannulated tetraphenylenes are reported. The palladium-catalyzed annulation of tetraiodo-substituted 2,3,6,7,10,11,14,15-octamethyltetraphenylene with insufficient di(4-anisyl)ethyne yielded a mixture of per-substituted [8]circulene and its non-planar fragments, including mono-, para-di-, ortho-di-, and triannulated products. Their structures were unambiguously verified by X-ray crystallography.

Dinaphthozethrene and Diindenozethrene: Synthesis, Structural Analysis, and Properties.

Zethrene-based condensed arenes dinaphthozethrene and diindenozethrene were synthesized by oxidative cyclodehydrogenation and palladium-catalyzed cyclization of 7,14-diarylzethrenes, respectively. Their structures were analyzed by X-ray crystallography. The photophysical and electrochemical properties of these compounds were investigated.

An Unconventional Approach to Induce Liquid-Crystalline Phases of Triazine-Based Dendrons by Breaking Their Self-Assembly into Dimers.

Three triazine-based dendrons (1 a-c) were successfully prepared in 70-83 % yields. These newly prepared dendrons are found to be liquid crystalline (LC). Computational investigations on molecular conformations and dipoles of triazine-based dendrons reveal that the substituent on the central triazine unit interrupts strong dipole or H-bond interactions to avoid dimeric formation.

Pyromellitic dithioimides: thionation improves air-stability and electron mobility of N-type organic field-effect transistors.

Thionation and fluorination of pyromellitic diimides (PyDIs) increased the electron mobility and on/off ratio of the original diimides by two orders of magnitude and improved the threshold voltage and air-stability of diimide compounds.

Linear oligoarylamines: electrochemical, EPR, and computational studies of their oxidative states.

A series of straight-chain oligoarylamines were synthesized and examined by electrochemical, spectroelectrochemical, electron paramagnetic resonance techniques, and density functional theory (DFT) calculation. Depending on their electrochemical characteristics, these oligoarylamines were classified into two groups: one containing an odd number and the other an even number of redox centers. In the systems with odd redox centers (N1, N3, and N5), each oxidation was associated with the loss of one electron.

Zethrene and dibenzozethrene: masked biradical molecules?

The syntheses, structures, and physical properties of dibenzozethrenes were explored. The results thus obtained were compared with those for zethrenes. Dibenzozethrenes were synthesized by the nickel-catalyzed cyclodimerization of 9-ethynyl-1-iodoanthracenes.

Highly curved bowl-shaped fragments of fullerenes: synthesis, structural analysis, and physical properties.

Highly curved buckybowls 3, 4, and 5 were synthesized from planar precursors, fluoranthenes 8, benzo[k]fluoranthenes 10 and naphtho[1,2-k]-cyclopenta[cd]fluoranthenes 12, respectively, using straightforward palladium-catalyzed cyclization reactions. These fluoranthene-based starting materials were easily prepared from 1,8-bis(arylethynyl)naphthalenes 6. Both buckybowls 3 and 4 are fragments of C60 , whereas 5 is a unique subunit of C70 .

Synthesis, structural analysis, and properties of [8]circulenes.

Polygons: [8]Circulenes were easily prepared by Pd-catalyzed annulations of tetraiodotetraphenylenes with alkynes. Their saddle-shaped structure with an [8]radialene character was identified by X-ray crystallography. Similar to 1,3,5,7-cyclooctatetraene, they have a tub-shaped eight-membered ring, but all of the bond lengths and bond angles are almost equal.

Infinite copper(II) coordination architectures from a resonative aminotriazine-derived tripodal ligand: synthesis, structures, and magnetic properties.

The ligand 2,4,6-tris(2-picolylamino)-1,3,5-triazine (o-H3tpat) with essentially resonative structure and two copper(II)-based one-dimensional coordination chain structures, [Cu3Cl5(o-H2tpat)(H2O)]·MeOH·CH2Cl2 (1) and [Cu2(o-H2tpat)(H2O)(MeOH)(NO3)2](NO3)·3MeOH (2), with different structural patterns have been synthesized and characterized using single crystal X-ray diffraction analysis. For o-H3tpat, two crystalline forms showing different solid-state structural features are obtained from MeOH/Et2O (form I) and CH2Cl2/Et2O (form II), respectively. The o-H3tpat form I adopts an asymmetric-configured all-amino resonative tautomer with three cis-trans-trans-arranged pyridyl groups, whereas the o-H3tpat form II adopts also an identical resonative structure but where two of the three pyridyl groups are in a cis-manner and the third one is nearly coplanar with the central aminotriazine core.

Studies on the structure of N-phenyl-substituted hexaaza[1(6)]paracyclophane: synthesis, electrochemical properties, and theoretical calculation.

The N-phenyl-substituted hexaaza[1(6)]paracyclophane (3, hexamer) has been synthesized successfully in two steps and the noncoplanar conformation was calculated by gaussian program. The electrochemical properties exhibited lots of interesting results and each overlapping oxidative wave contained two-electron transfer.

Synthesis and structural analysis of a highly curved buckybowl containing corannulene and sumanene fragments.

Buckybowls 7, 9, and 10 were prepared from benzo[k]fluoranthene 6 and fluoranthene 8 using straightforward procedures involving key palladium-catalyzed cyclization reactions. The structures of bowl-shaped molecules 7 and 10 were determined by using X-ray crystallographic methods. The observed p-orbital axis vector (POAV) angle of 7 was found to be 12.

Palladium-catalyzed cycloisomerizations of diarylacetylenes: synthesis, structures, and physical properties of highly substituted naphthalenes and 8,8 a-dihydrocyclopenta[a]indenes.

Depending on the electronic properties of their substituents, the major products generated by palladium-catalyzed cycloisomerizations of diarylalkynes are either highly substituted 8,8a-dihydrocyclopenta[a]indenes 3 or naphthalenes 4. The structures of these compounds were verified by X-ray crystallographic analysis. Many functional groups tolerated the reaction conditions evaluated in this study.