The linear and nonlinear (chir)optical properties of four oligoamide foldamers with different donor groups are studied by means of time-dependent density functional theory calculations. It is shown that stronger donors yield larger hyperpolarizabilities due to low-lying charge–transfer states. The agreement with the experiments concerning the key bands in the electronic circular dichroism spectra and the hyper-Rayleigh scattering (HRS) quantities is rather good, though some discrepancies remain in the depolarization ratio and HRS optical activity quantities.

The linear and nonlinear (chir)optical properties of a series of four oligoamide foldamers, containing different electron-donor groups in the same position, have been studied by means of quantum chemistry (QC) calculations at the time-dependent density functional theory (TDDFT) level. In particular, the electronic circular dichroism (ECD), the electric field induced second harmonic generation, the hyper-Rayleigh scattering (HRS), and finally the HRS optical activity (HRSOA) spectroscopies have been simulated. Structure–property relationships emerge: systems bearing stronger donors exhibit the largest electric-dipole first hyperpolarizabilities. This is attributed to the presence of a low-lying excited state characterized by a nonlocal intramolecular charge transfer and a large electric-dipole moment variation. Analyses based on the unit sphere representation further identify the directions of maximum induced second-order polarization and clarify the dipolar versus octupolar nature of the whole responses. Although the predicted β HRS values and the key ECD bands show good agreement with the experiments, some discrepancies are observed in the depolarization ratio of HRS and in the circular differential scattering ratio of HRS-OA. Overall, this study establishes clear links between the structural features and the linear and nonlinear (chir)optical properties, and it demonstrates the current power of modern QC to tackle large and intricate chiral systems.

Redox-dependent luminescence in a molecular pentavalent uranyl complex supported by a pyridine dipyrrolide pincer ligand is presented. Electrochemical and chemical reduction of the uranyl(VI) species provides a stable uranyl(V) complex that emits blue light from a high-energy excited state. The anti-Kasha emission is credited to the presence of “nested” excited states that disfavor relaxation to lower-energy excited states.

The chemistry of pentavalent uranyl is of high interest due to the ion's central role as an intermediate in nuclear separations. However, due to the instability of [UO2]+, little is known about its electronic structure. The synthesis and characterization of a pentavalent uranyl complex supported by a pyridine dipyrrolide pincer-type ligand are reported. The pentavalent species is isolated following reduction of the hexavalent uranyl congener, allowing for direct comparisons to be made between the two species. The [UO2]2+ analog is nonemissive, but upon reduction, luminescence is “switched on” in the pentavalent uranyl complex, affording emission from a high-energy state. Quantum chemical calculations support the experimental findings and help provide insight into the electronic structure of the excited states of the reduced complex. This work provides a unique example of ligand-based non-Kasha emission from a molecular pentavalent uranyl complex.

Cathepsin B-sensitive peptide–adjuvant conjugates are designed, synthesized, and evaluated to deliver an antigenic peptid and an adjuvant targeting Toll-like receptors 7 and 8 (TLR7/8) to antigen presenting cells. The adjuvant is released by cathepsin B resulting in antigen presentation and TLR mediated T cell activation. This strategy offers a promising approach to developing effective therapeutic cancer vaccines.

Therapeutic cancer vaccines have emerged as a promising approach to raise an immune response against tumors. These vaccines work by stimulating dendritic cells to present tumor-associated antigens, thereby activating T cells that target cancer cells. To enhance immune responses, adjuvants targeting pattern recognition receptors are often used. Toll-like receptor 7 (TLR7) and TLR8 agonists, which play key roles in initiating T Helper 1 (Th1) immunity, are central to this process. After screening a set of structurally different small molecule TLR7/8 agonists, resiquimod (R848) and a diaminoquinazoline were selected for the conception of cleavable adjuvant-antigen conjugates. To this end, the ovalbumin derived T cell epitope containing SIINFEKL was covalently linked to the ligand through a cathepsin B-sensitive linker, enabling controlled release of the adjuvant upon cleavage by intracellular cathepsin B, allowing controlled dendritic cell maturation and enhanced T cell activation.

Layered structures (LuFeO3) n LuFe2O4 exhibit a common structural transformation upon oxygen uptake. Although the LuFeO3 units do not directly participate in oxygen insertion, these inactive layers nevertheless influence the temperature at which oxygen absorption occurs.

Herein, a structural shearing behavior in heterolayered (LuFeO3) n LuFe2O4 (n = 0, 1) upon oxygen uptake is reported. Using advanced X-ray and electron diffraction techniques, it is found that when (LuFeO3) n LuFe2O4 absorbs oxygen, only the LuFe2O4 layer is affected, transforming into LuFe2O4.5, while the LuFeO3 layer remains chemically unchanged. Magnetic susceptibility and Mössbauer spectroscopy corroborate this local oxygen uptake in the LuFe2O4 layer by confirming the mixed oxidation state of the iron site. Interestingly, even though the LuFeO3 layer in the n = 1 compound does not directly absorb oxygen, it significantly influences how the structure evolves during oxidation. The n = 1 compound (Lu2Fe3O7) is active for oxygen absorption at a lower temperature than the n = 0 compound LuFe2O4 (110 °C vs. 150 °C from thermal gravimetric measurement). The LuFeO3 layer in Lu2Fe3O7 acts as a buffer zone that reduces strain and chemical pressure within the LuFe2O4 layer thereby enhancing the rate of oxygen absorption. The findings reveal a common behavior in the (LuFeO3) n LuFe2O4 series that provides new insights into the design of ternary oxides active at low temperatures for fast oxygen uptake. This crystallographic study can therefore lead to further improvements in the oxygen storage capability and oxygen absorption rates.

Oxidative addition is used for the site-specific incorporation of an organometallic PtII complex as an artificial nucleobase into a DNA duplex. The platination stabilizes the duplex and confers it with phosphorescence.

An organometallic phosphorescent PtII complex is introduced into DNA duplexes via oxidative addition to a tailor-made artificial nucleobase, acting as an N^N^C donor ligand. Its covalent attachment to the nucleic acid backbone localizes the metal ion in the center of the duplex. The platination exerts a stabilizing effect of up to 6.4 °C on the duplex, with the degree of stabilization depending on the identity of the nucleobase in the complementary position. No interstrand crosslink is formed, as indicated by mass-spectrometry and corroborated by almost identical photoluminescence lifetimes (τ) in Ar-purged solution. In air-equilibrated solution, τ shows moderate dependence on the complementary nucleobase, suggesting that the latter influences oxygen accessibility to the luminophore. When two PtII complexes are incorporated in neighboring positions, a redshifted luminescence from aggregates is observed in addition to monomer emission, indicating Pt···Pt interactions along the helical axis. The approach presented here allows the site-specific incorporation of highly stable PtII complexes as phosphorescent tags into nucleic acids.

Discussion on oxide interfaces in gallium-based liquid metals have concentrated on their properties, behaviors, and related applications. However, the molecular mechanisms underlying effects, as well as the differences between the presence and absence of the oxide layer, have been less thoroughly discussed. In this article, oxide interfaces are critically assessed from a dual standpoint, highlighting both their evident advantages and potential drawbacks.

Oxide interfaces in gallium-based liquid metals (Ga-based LMs) are of paramount importance, given their substantial influence on the material properties and performance across a range of applications. The emergence of these interfaces presents a double-edged sword, providing both significant advantages and potential drawbacks. While a self-limiting, protective oxide layer improves wettability and functionality, it also restricts fluidity and alters the alloy's fundamental properties. Therefore, understanding the dual role of oxide interfaces—as both a protective barrier and a potential risk—is essential for optimizing its application in fields such as flexible electronics, energy conversion, catalysis, and bioengineering. This article reviews the mechanisms behind oxidation, regulation techniques, and the interactions and reactivity at oxide interfaces. By examining their roles in both enhancing and restricting the performance of Ga-based LMs, insights into the delicate balance necessary to maximize benefits while mitigating risks in practical applications are offered.

Following the Danube Flow. The first total syntheses of highly brominated rubrolides T, U, and U-analog, together with the efficient and divergent syntheses of rubrolides A, D, and P. The dibrominated key intermediate, obtained via a Suzuki-Miyaura cross-coupling reaction, is the centerpiece of the synthesis. The compounds are tested for their antibiofilm activity against both Gram-positive and Gram-negative bacteria.

Rubrolides are marine natural products with numerous biological activities. Over the last few decades, more than 20 members of this natural product class have been isolated, but their mode of action remains unknown. All compounds share a furanone core structure with β-aryl and γ-benzylidene substituents. The highly brominated rubrolides T, U, and an analog of rubrolide U are synthesized for the first time. Furthermore, the developed method enables the synthesis of natural rubrolides A, D, and P as pure Z-isomers. The synthetic approach employs a Suzuki-Miyaura cross-coupling reaction with a dibrominated aromatic boronic species as the key step, followed by a vinylogous Aldol condensation to introduce the second aromatic substituent. The synthesized compounds are biologically tested and show outstanding antibiofilm activity for Stenotrophomonas maltophilia, Bacillus subtilis, and Staphylococcus aureus. All synthesized compounds shows only negligible effects at GABAA receptors, suggesting that they are unlikely to exert neurotoxic effects at a concentration of 10 µM.

This review presents an environmentally sustainable strategy to address the critical issue of escalating atmospheric CO2 levels. It explores the application of metal-free covalent organic frameworks in a photocatalytic approach, offering a green and efficient strategy for carbon dioxide reduction and contributing to climate change mitigation.

Carbon dioxide (CO2), a major greenhouse gas, is undoubtedly in urgent need of mitigation as its concentration in the atmosphere is rising at an alarming rate, leading to numerous environmental consequences, most notably the serious problem of climate change. Researchers are, therefore, looking for different ways to reduce carbon dioxide. In this article, the use of atmospheric CO2 gas as a C1 feedstock is a prominent approach, as the effective conversion of CO2 into fuels can provide a viable option to produce several industrial organic fuels. Among the various types of photocatalysts, covalent organic frameworks (COFs) have garnered significant interest because of their well-defined structures, durable frameworks, intrinsic porosity, and promising photocatalytic performance. Consequently, extensive research has been conducted to explore the photocatalytic capabilities of COFs in the field of CO2 reduction. Therefore, this comprehensive article highlights the latest developments and advances in metal-free COF-based photocatalytic CO2 reduction. It also outlines and compares different types of linkers used as COF building blocks, which are highly efficient in the CO2 reduction reaction. The article concludes with an overview of the current challenges and potential directions for future research in the field of COF-based photocatalysis.

Reacting Bis2GaBr (Bis = CH(SiMe3)2) with Bis2AlH selectively yields Bis2GaH, a monomeric hydride in solution, characterized by diffusion ordered spectroscopy NMR, infrared spectroscopy and indirectly via hydrogallation. A one-pot route enables frustrated Lewis pairs Bis2EOPtBu2 (E = Al, Ga), with the gallium analog splitting H2 and showing a dynamic temperature-dependent equilibrium revealed by variable-temperature NMR studies.

Extremely sterically demanding bis(bis(trimethylsilyl)methyl)-substituted aluminum and gallium compounds are particularly suitable for applications in frustrated Lewis pair (FLP) chemistry. A selective exchange reaction between Bis2GaBr (Bis = CH(SiMe3)2) and Bis2AlH affords the previously inaccessible Bis2GaH, a monomeric gallium hydride, in solution, as confirmed by diffusion ordered spectroscopy NMR, IR spectroscopy, quantum chemical calculations, and—indirectly—by hydrogallation of phenylacetylene. A simple one-pot route enables access to Bis2EOP t Bu2 FLPs (E = Al, Ga) via formal HBr adducts and subsequent deprotonation with KHMDS. As predicted for Bis2GaOP t Bu2, H2 activation is favored, although it proceeds slowly and irreversibly. Surprisingly, variable-temperature NMR studies unveil a dynamic equilibrium between the H2 adduct Bis2Ga(H)OP(H) t Bu2 and the free gallium hydride and phosphine oxide, shedding new light on reversible hydrogen activation in main-group FLP systems.

The study examines the coordination chemistry of indium teflate complexes, showing the progression from [In(OTeF5)3(THF)3] to the anionic species [In(OTeF5)4(THF)2]– and [In(OTeF5)6]3–. Systematic ligand substitution and anion formation reveal increasing teflate coordination, highlighting structural evolution, Lewis acidity modulation, and stabilization by weakly coordinating environments.

This study explores the synthesis and characterization of novel indium-based pentafluoroorthotellurate (teflate) derivatives. It introduces a series of indium(III) teflate mono- and trianions, including [In(OTeF5)4(THF)2]– and [In(OTeF5)6]3–. The research utilizes low-temperature single-crystal X-ray diffraction, IR, and NMR spectroscopy to provide the first structural insights into these indium(III) teflate anions. The neutral Lewis acid [In(OTeF5)3] is successfully synthesized as its THF adduct [In(OTeF5)3(THF)3] via a salt metathesis reaction with InCl3 and AgOTeF5. Quantum-chemical calculations and catalytic tests highlight the pronounced Lewis acidity of the indium center in these compounds.