T-Shaped-N-Doped Polycyclic Aromatic Hydrocarbons: A New Concept of Dopant-Free Organic Hole-Transporting Materials for Perovskite Solar Cells.

Although metal halide perovskites are positioned as the most powerful light-harvesting materials for sustainable energy conversion, there is a need for a thorough understanding of molecular design principles that would guide better engineering of organic hole-transporting materials, which are vital for boosting the performance and stability of perovskite solar cells. To address this formidable challenge, here, we developed a new design strategy based on the curved N-doped polycyclic aromatic hydrocarbon merged with T-shaped phenazines being decorated with (phenyl)-di--methoxyphenylamine (OMeTAD)─N-PAH23/24 and -3,6-ditertbutyl carbazole (TBCz)─N-PAH25/26. As N-PAH23/24 exhibited satisfying thermal stability, the comparative studies performed with various experimental and simulation methods revealed a pronounced correlation between the depth of the central cyclazine core and the form of the T-shape units.

Synthesis, photophysical characterisation, quantum-chemical study and antiproliferative activity of cyclometalated Ir(III) complexes based on 3,5-dimethyl-1-phenyl-1-pyrazole and N,N-donor ligands.

In this paper, we present the synthesis of four new complexes: the dimeric precursor [Ir(dmppz)(-Cl)] (1) (Hdmppz - 3,5-dimethyl-1-phenyl-1-pyrazole) and heteroleptic bis-cyclometalated complexes: [Ir(dmppz)(PyCO)]PF·½CHCl (2), [Ir(dmppz)(Hbiim)]PF·HO (3), and [Ir(dmppz)(PyBIm)]PF (4), with auxiliary N,N-donor ligands: 2-di(pyridyl)ketone (PyCO), 2,2'-biimidazole (Hbiim) and 2-(2'-pyridyl)benzimidazole (PyBIm). In the obtained complexes, SC-X-ray analysis revealed that Ir(III) has an octahedral coordination sphere with chromophores of the type {IrNCCl} (1) or {IrNC} (2-4). The complexes obtained, which have been fully characterised by physicochemical methods (CHN, TG, FTIR, UV-Vis, PL and H, C, N NMR), were used to continue our studies on the factors influencing the cytotoxic properties of potential chemotherapeutic agents ().

Controlled hydrolysis of AlMe to tetramethylalumoxane and a new look at incipient adducts with water.

We present an efficient route to tetramethylalumoxane by the controlled hydrolysis of AlMe in the presence of pyridine. The AlMe(pyr) hydrolysis by 0.5 and 1 equiv.

Fresh Impetus in the Chemistry of Calcium Peroxides.

Redox-inactive metal ions are essential in modulating the reactivity of various oxygen-containing metal complexes and metalloenzymes, including photosystem II (PSII). The heart of this unique membrane-protein complex comprises the MnCaO cluster, in which the Ca ion acts as a critical cofactor in the splitting of water in PSII. However, there is still a lack of studies involving Ca-based reactive oxygen species (ROS) systems, and the exact nature of the interaction between the Ca center and ROS in PSII still generates intense debate.

An unprecedented roll-off ratio in high-performing red TADF OLED emitters featuring 2,3-indole-annulated naphthalene imide and auxiliary donors.

The capability of organic emitters to harvest triplet excitons a thermally activated delayed fluorescence (TADF) process has opened a new era in organic optoelectronics. Nevertheless, low brightness, and consequently an insufficient roll-off ratio, constitutes a bottleneck for their practical applications in the domain of organic light-emitting diodes (OLEDs). To address this formidable challenge, we developed a new design of desymmetrized naphthalimide (NMI) featuring an annulated indole with a set of auxiliary donors on its periphery.

Uncovering Factors Controlling Reactivity of Metal-TEMPO Reaction Systems in the Solid State and Solution.

Nitroxides find application in various areas of chemistry, and a more in-depth understanding of factors controlling their reactivity with metal complexes is warranted to promote further developments. Here, we report on the effect of the metal centre Lewis acidity on both the distribution of the O- and N-centered spin density in 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) and turning TEMPO from the O- to N-radical mode scavenger in metal-TEMPO systems. We use Et(Cl)Zn/TEMPO model reaction system with tuneable reactivity in the solid state and solution.

Regioisomerism vs Conformation: Impact of Molecular Design on the Emission Pathway in Organic Light-Emitting Device Emitters.

Despite the design and proposal of several new structural motifs as thermally activated delayed fluorescent (TADF) emitters for organic light-emitting device (OLED) applications, the nature of their interaction with the host matrix in the emissive layer of the device and their influence on observed photophysical outputs remain unclear. To address this issue, we present, for the first time, the use of up to four regioisomers bearing a donor-acceptor-donor electronic structure based on the desymmetrized naphthalene benzimidazole scaffold, equipped with various electron-donating units and possessing distinguished conformational lability. Quantum chemical calculations allow us to identify the most favorable conformations adopted by the electron-rich groups across the entire pool of regioisomers.

Facile Functionalization of Ambipolar, Nitrogen-Doped PAHs toward Highly Efficient TADF OLED Emitters.

Despite promising optoelectronic features of N-doped polycyclic aromatic hydrocarbons (PAHs), their use as functional materials remains underdeveloped due to their limited post-functionalization. Facing this challenge, a novel design of N-doped PAHs with D-A-D electronic structure for thermally activated delayed fluorescence (TADF) emitters was performed. Implementing a set of auxiliary donors at the meta position of the protruding phenyl ring of quinoxaline triggers an increase in the charge-transfer property simultaneously decreasing the delayed fluorescence lifetime.

MALDI MSI and Raman Spectroscopy Application in the Analysis of the Structural Components and Flavonoids in Stem.

Nod factors among the signaling molecules produced by rhizobia in response to flavonoids to induce root nodule formation in the legumes. It is, however, hypothesized that they might increase the yield and positively impact the growth of non-legumes. To evaluate this statement, rapeseed treated with Nod factor-based biofertilizers were cultivated, their stems was collected, and the metabolic changes were investigated using Raman spectroscopy and MALDI mass spectrometry imaging.

MP2-Based Correction Scheme to Approach the Limit of a Complete Pair Natural Orbitals Space in DLPNO-CCSD(T) Calculations.

The domain-based local pair natural orbital (PNO) coupled-cluster DLPNO-CCSD(T) method has been proven to provide accurate single-point energies at a fraction of the cost of canonical CCSD(T) calculations. However, the desired "chemical accuracy" can only be obtained with a large PNO space and extended basis set. We present a simple yet accurate and efficient correction scheme based on a perturbative approach.

Aqueous-phase photo-oxidation of selected green leaf volatiles initiated by OH radicals: Products and atmospheric implications.

C- and C- unsaturated oxygenated organic compounds emitted by plants under stress like cutting, freezing or drying, known as Green Leaf Volatiles (GLVs), may clear some of the existing uncertainties in secondary organic aerosol (SOA) budget. The transformations of GLVs are a potential source of SOA components through photo-oxidation processes occurring in the atmospheric aqueous phase. Here, we investigated the aqueous photo-oxidation products from three abundant GLVs (1-penten-3-ol, (Z)-2-hexen-1-ol, and (E)-2-hexen-1-al) induced by OH radicals, carried out in a photo-reactor under simulated solar conditions.

V-shaped donor-acceptor organic emitters. A new approach towards efficient TADF OLED devices.

We report the synthesis and characterization of a series of donor-acceptor TADF emitters with a new architecture, where the donor moiety and the dibenzazepine-based acceptor moiety are separated by a phenylene linker in a V-shaped spatial arrangement. Such spatial separation and electronic decoupling between the donor and the acceptor moieties leads to low singlet-triplet energy gaps and favors efficient exciton up-conversion.

Chromophore hydrolysis and release from photoactivated rhodopsin in native membranes.

For sustained vision, photoactivated rhodopsin (Rho*) must undergo hydrolysis and release of all--retinal, producing substrate for the visual cycle and apo-opsin available for regeneration with 11--retinal. The kinetics of this hydrolysis has yet to be described for rhodopsin in its native membrane environment. We developed a method consisting of simultaneous denaturation and chromophore trapping by isopropanol/borohydride, followed by exhaustive protein digestion, complete extraction, and liquid chromatography-mass spectrometry.

Tandem rigidification and π-extension as a key tool for the development of a narrow linewidth yellow hyperfluorescent OLED system.

Hyperfluorescence (HF), a relatively new phenomenon utilizing the transfer of excitons between two luminophores, requires careful pairwise tuning of molecular energy levels and is proposed to be the crucial step towards the development of new, highly effective OLED systems. To date, barely few HF yellow emitters with desired narrowband emission but moderate external quantum efficiency (EQE < 20%) have been reported. This is because a systematic strategy embracing both Förster resonance energy transfer (FRET) and triplet to singlet (TTS) transition as complementary mechanisms for effective exciton transfer has not yet been proposed.

Understanding structure-properties relationships of porphyrin linked to graphene oxide through π-π-stacking or covalent amide bonds.

Two graphene oxide nanoassemblies using 5-(4-(aminophenyl)-10,15,20-triphenylporphyrin (TPPNH) were fabricated by two synthetic methods: covalent (GO-CONHTPP) and noncovalent bonding. GO-CONHTPP was achieved through amide formation at the periphery of GO sheets and the hybrid material was fully characterized by FTIR, XPS, Raman spectroscopy, and SEM. Spectroscopic measurements together with theoretical calculations demonstrated that assembling TPPNH on the GO surface in DMF-HO (1:2, v/v) via non-covalent interactions causes changes in the absorption spectra of porphyrin, as well as efficient quenching of its emission.

Simulation and analysis of the relaxation dynamics of a photochromic furylfulgide.

Furylfulgides, a class of photochromic organic compounds, show a complex system of photoinduced reactions. In the present study, the excited-state dynamics of the and isomers of a representative furylfulgide is modelled with the use of nonadiabatic molecular dynamics simulations. Moreover, a pattern recognition algorithm is employed in order to automatically identify relaxation pathways, and to quantify the photoproduct distributions.

COVID-19 Vaccination in Inflammatory Bowel Disease (IBD).

Vaccines against SARS-CoV-2 are believed to play a key role in the suppression of the COVID-19 pandemic. However, patients suffering from inflammatory bowel diseases (IBD) were excluded from SARS-CoV-2 vaccines trials. Therefore, concerns regarding vaccination efficacy and safety among those patients were raised.

A New Look at Molecular and Electronic Structure of Homoleptic Diiron(II,II) Complexes with N,N-Bidentate Ligands: Combined Experimental and Theoretical Study.

Paddlewheel-type binuclear complexes featuring metal-metal bonding have been the subject of widespread interest due to fundamental concern in their electronic structures and potential applications. Here, we explore the molecular and electronic structures of diiron(II,II) complexes with N,N'-diarylformamidinate ligands. While a paddlewheel-type diiron(II,II) complex with N,N'-diphenylformamidinate ligands (DPhF) exhibits the centrosymmetric [Fe (μ-DPhF) ] structure, a minor alteration in the ligand system, i.

Modular Nitrogen-Doped Concave Polycyclic Aromatic Hydrocarbons for High-Performance Organic Light-Emitting Diodes with Tunable Emission Mechanisms.

Although bowl-shaped N-pyrrolic polycyclic aromatic hydrocarbons (PAHs) can achieve excellent electron-donating ability, their application for optoelectronics is hampered by typically low photoluminescence quantum yields (PLQYs). To address this issue, we report the synthesis and characterization of a series of curved and fully conjugated nitrogen-doped PAHs. Through structural modifications to the electron-accepting moiety, we are able to switch the mechanism of luminescence between thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP), and to tune the overall PLQY in the range from 9 % to 86 %.

HAB79: A new molecular dataset for benchmarking DFT and DFTB electronic couplings against high-level ab initio calculations.

A new molecular dataset called HAB79 is introduced to provide ab initio reference values for electronic couplings (transfer integrals) and to benchmark density functional theory (DFT) and density functional tight-binding (DFTB) calculations. The HAB79 dataset is composed of 79 planar heterocyclic polyaromatic hydrocarbon molecules frequently encountered in organic (opto)electronics, arranged to 921 structurally diverse dimer configurations. We show that CASSCF/NEVPT2 with a minimal active space provides a robust reference method that can be applied to the relatively large molecules of the dataset.

NMR Crystallography Enhanced by Quantum Chemical Calculations and Liquid State NMR Spectroscopy for the Investigation of Se-NHC Adducts*.

N-heterocyclic carbene ligands (NHC) are widely utilized in catalysis and material science. They are characterized by their steric and electronic properties. Steric properties are usually quantified on the basis of their static structure, which can be determined by X-ray diffraction.

Simulation and Analysis of the Transient Absorption Spectrum of 4-(,-Dimethylamino)benzonitrile (DMABN) in Acetonitrile.

4-(,-Dimethylamino)benzonitrile (DMABN) is a well-known model compound for dual fluorescence-in sufficiently polar solvents, it exhibits two distinct fluorescence emission bands. The interpretation of its transient absorption (TA) spectrum in the visible range is the subject of a long-standing controversy. In the present study, we resolve this issue by calculating the TA spectrum on the basis of nonadiabatic molecular dynamics simulations.

Theoretical Study of the Photoisomerization Mechanism of All--Retinyl Acetate.

The compound 9--retinyl acetate (9--RAc) is a precursor to 9--retinal, which has potential application in the treatment of some hereditary diseases of the retina. An attractive synthetic route to 9--RAc is based on the photoisomerization reaction of the readily available all--RAc. In the present study, we examine the mechanism of the photoisomerization reaction with the use of state-of-the-art electronic structure calculations for two polyenic model compounds: -octatetraene and -2,6-dimethyl-1,3,5,7,9-decapentaene.

Rational Alteration of Pharmacokinetics of Chiral Fluorinated and Deuterated Derivatives of Emixustat for Retinal Therapy.

Recycling of all--retinal to 11--retinal through the visual cycle is a fundamental metabolic pathway in the eye. A potent retinoid isomerase (RPE65) inhibitor, ()-emixustat, has been developed and tested in several clinical trials; however, it has not received regulatory approval for use in any specific retinopathy. Rapid clearance of this drug presents challenges to maintaining concentrations in eyes within a therapeutic window.