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G-quadruplexes (G4s) are non-canonical secondary structures that play a crucial role in the regulation of genetic expression. This study explores the interaction between G4s and a small family of oligostyrylbenzene (OSB) derivatives, characterized by tris(styryl)benzene and tetrastyrylbenzene backbones, functionalized with either trimethylammonium or 1-methylpyridinium groups. Initially identified as DNA ligands, these OSB derivatives have now been recognized as potent G4 binders, surpassing in binding affinity commercially available ligands such as pyridostatin and displaying good selectivity for G4s over duplex DNA. Furthermore, OSB derivatives 1 and 2 demonstrated significant antiparasitic activity against bloodstream forms of T. brucei and extracellular L. major, with high selectivity indices when compared to MRC-5 healthy control cells. Derivatives 1 and 2 exhibited moderate biocidal effects against a range of Gram-positive and Gram-negative bacterial strains. Notably, a synergistic antibacterial effect was observed when these compounds were combined with traditional antibiotics, particularly against Acinetobacter baumannii, highlighting their potential utility in addressing drug-resistant bacterial infections. The differences in bioactivity among the OSB derivatives can be attributed to variations in cellular uptake, as proved by flow cytometry analysis. This suggests that the degree of cellular internalization plays a pivotal role in the observed antiparasitic and antibacterial efficacy. [ABSTRACT FROM AUTHOR]

The shape and size‐controlled synthesis of colloidal I−III−VI quantum dots (QDs) can be attained only by a few synthesis strategies via the introduction of various high‐boiling‐point organic surfactants. To further investigate this strategy, in this study, we present a surfactant‐associated controlled synthesis of copper (Cu)‐deficient, zinc (Zn)‐doped Cu─indium (In)─selenium (Se) QDs, followed by a mechanistic investigation of their photophysical properties using surfactants, such as oleylamine (OLA), oleic acid (OA), and diphenylphosphine (DPP). OLA significantly promoted the quantum size effect‐resultant emission wavelength red‐shift, while OA controlled the homogeneous growth of QDs and improved the quantum yields. Moreover, Gaussian deconvolution of the photoluminescence spectra and the bandgap derived from the absorption spectra, by fitting, supported the fact that the radiative transition channels, especially for surface‐trap‐state‐related transitions, are also dependent on the surfactants. Specifically, the conduction band electron‐intragap state transitions and donor‐acceptor transitions were present in all the prepared samples but accounted for different percentages. Furthermore, the surface‐trap‐state‐related transitions significantly faded upon adding (i) OLA/OA as the sole surfactant to the cationic precursor and (ii) the OA + OLA + DPP mixture to the anionic precursor. The findings described here are expected to provide a general strategy for enhancing the tunability of photophysical properties in other QDs systems. [ABSTRACT FROM AUTHOR]

A robust, metal‐free and K2CO3‐mediated method has been developed to access highly diversified pyrazole C‐3/4/5 linked 1,3,4‐oxadiazole derivatives through the formation of C−O/C−N bonds in a one‐pot operation. This domino methodology was facilitated by utilizing pyrazole C‐3/4/5 carbaldehydes and benzohydrazides as starting substrates to generate the interesting molecular hybrids with high yields. The photophysical properties were also evaluated of the synthesized derivatives and exhibited good results with more than seven parameters. The fluorescence quantum yield of the pyrazole based 1,3,4‐oxadiazole was reached up to 75 %. The salient features of this approach are diversity‐oriented synthesis, metal‐free strategy, high yields and superior atom economy. [ABSTRACT FROM AUTHOR]

We report a step-economic strategy for the direct synthesis of novel polycyclic N-heterocycle-fused naphthoquinones by merging intramolecular oxidative coupling and cascade [4 + 2] cycloaddition. In the protocol, mechanistic investigations suggest that the cascade reaction involves the intermediate spiro polycyclic N-heterocycles and [4 + 2] cycloaddition processes. This protocol is featured with moderate to excellent yields, wide substrate scope, and divergent structures of products. In addition, the photophysical properties of the synthesized products were evaluated. These products exhibit interesting fluorescence properties, and surprisingly, the compounds have the ability to selectively recognize trifluoroacetic acid. [ABSTRACT FROM AUTHOR]

A novel Schiff base (BSSMO) and its copper complex have been synthesized, and their structure was delineated using single crystal XRD studies. Computational techniques were used to design and evaluate BSSMO‐based luminophores, revealing a significant intramolecular hydrogen bond within the molecule. Understanding ESIPT is crucial for optimizing photophysical and luminophore properties of organic molecules, especially for advancing optoelectronic devices. The study also explored the mechanisms of GSIPT and ESIPT for these BSSMO‐based luminophores using transition state theory, charge distribution, molecular orbital analysis, and quantum theory of atoms in molecules. Results advocated that BSSMO‐L2 exhibits higher absorption compared with BSSMO‐L1 and the same trend is observed in emission spectral studies. However, the intensity of enol emissions in BSSMO‐L2 is lower than that of keto (BSSMO‐L3) emissions and the S1 (Keto form) emission of BSSMO‐L3 shows significantly larger values, making it attractive for optoelectronic devices. The findings offer valuable insights for the development of ESIPT emitters with distinct photophysical properties. The in silico antidiabetic study of BSSMO‐L2 explores the interaction with PPAR‐γ protein, revealing a moderate affinity and stable complex, enhancing its bio‐potential for future applications. The in vitro anticancer study of Cu‐BSSMO‐L2 complex shows a potential anticancer effect through mitochondrial and extrinsic death receptor mediated pathways. These insights contribute to the design of novel benzenesulfonamide‐based bioactive molecules. [ABSTRACT FROM AUTHOR]

Based on the reported spiro organoboron compounds (PS1 and PS2 as potent 1O2 sensitizers), several new organoboron molecules (PS4–PS9) were constructed through structural modification, and their low‐lying excited states and photophysical properties have been explored by density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations. The predicted effective intersystem crossing (ISC) processes arise from the S1→T2 transition for PS4–PS6 and the S1→T4 transition for PS1, and corresponding KISC rate constants reach the order of magnitude of 109 (s−1). The organoboron compounds with a (N, N) chelate acceptor are predicted to exhibit relatively higher ISC efficiency than those bearing a (N, O) acceptor, and the planar C3NBN ring and the orthogonal configuration between the donor and acceptor moieties are responsible for the ISC rate enhancement. Importantly, the geometric features of the lowest singlet excited state (S1) for these compounds play a decisive role in their photosensitive efficiency. The present results provide a basis for better understanding of the photosensitivity of these spiro organoboron compounds and the structural modification effect. [ABSTRACT FROM AUTHOR]

A novel category of asymmetric boron chromophores with the attachment of two BF2 moieties denoted as BOPAM has been successfully synthesized via a one‐pot three‐step reaction starting from N‐phenylbenzothioamide. This synthetic route results in the production of [a] and [b]benzo‐fused BOPAMs along with post‐functionalization of the [a]benzo‐fused BOPAMs. The photophysical properties of these compounds have been systematically investigated through steady‐state absorption and fluorescence emission measurements in solvents at both ambient and cryogenic temperatures, as well as in the solid state. Computational methods have been employed to elucidate the emissive characteristics of the benzo‐fused BOPAMs, revealing distinctive photophysical attributes, including solvent‐dependent fluorescence intensity. Remarkably, certain BOPAM derivatives exhibit noteworthy photophysical phenomena, such as the induction of off‐on fluorescence emission under specific solvent conditions and the manifestation of intermolecular charge transfer states in solid‐state matrices. Through post‐functionalization strategies involving the introduction of electron‐donating groups onto the [a]benzo‐fused BOPAM scaffold, an intramolecular charge transfer (ICT) pathway is activated, leading to substantial fluorescence quenching via non‐radiative decay processes. Notably, one [a]benzo‐fused BOPAM variant exhibits a pronounced fluorescence enhancement upon exposure to acidic conditions, thereby underscoring its potential utility in pH‐sensing applications. [ABSTRACT FROM AUTHOR]

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A novel series of D−A−D-type 9-phenyl-9-phosphafluorene oxide (PhFlOP) derivatives was prepared and is reported herein. The synthetic protocol involved 5 steps from commercially available 2-bromo-4-fluoro-1-nitrobenzene, featuring a noble-metal-free system, mild reaction conditions, and a good yield, especially for the final Cs2CO3-facilitated nucleophilic substitution (77–91% yield). The characterization data obtained from IR and NMR spectroscopy (1H, 13C, 19F, and 31P) as well as HRMS spectrometry were in full agreement with the expected structures, and single-crystal X-ray diffraction analysis was conducted to confirm the structure of compound 7-H. Moreover, the photophysical properties of these PhFlOP derivatives were determined by UV–vis absorption and photoluminescence studies, revealing that their photophysical behavior can be affected by the different substituents in the donor carbazole group.

Introduction of non‐hexagons and/or heteroatoms allows for finely tuning the physicochemical properties of nanographenes. Heteroatoms doping have dominated the modulation of nanographenes with tunable band gap, rich electrochemical activities and so on. The pair of non‐hexagons, for instance, pentagon‐heptagon pairs, have furnished nanographenes with aromatic and/or antiaromatic characteristics, open‐shell properties and so on. In order to meet the growing demand for versatile nanographenes in materials science, research on novel nanographenes with heteroatom doped non‐hexagonal pairs has been aroused in recent years. In this review, we focus on nanographenes with nitrogen‐doped non‐hexagonal paris including the synthesis, structure analysis, photophysical properties, and potential applications in organic devices. [ABSTRACT FROM AUTHOR]

In order to study the connection between structure of the molecular and sensitizing performance in dye-sensitized solar cells, four new organic sensitizers with donor-pi spacer-acceptor structures were designed and synthesized. The structural characterization of all dye sensitizers was investigated using FT-IR, 13C and 1H NMR, CHN and UV–visible analyses. The electronic orbital transitions and optical properties were determined and discussed. (E)-2-cyano-3-(5-(3-(di-p-tolylamino)phenyl)furan-2-yl)acrylic acid (TPCA), (Z)-2-cyano-N′-((5-(3-(di-p-tolylamino)phenyl)furan-2-yl)acetohydrazide (TPCH), (E)-3-(5-(4-(bis(4-methoxyphenyl)amino)phenyl)furan-2-yl)-2-cyanoacrylic acid (MTPCA), and (Z)-N′-((5-(4-(bis(4-methoxyphenyl)amino)phenyl)furan-2-yl)methylene)-2-cyanoacetohydrazide exhibited band gaps (Egap) in the range from 1.51 to 1.78 eV with λabs in the range of 486–589 nm. The dyes' energy levels were investigated using the cyclic voltammetry technique and DFT calculations. To complement the comprehensive optical, electrochemical, and photovoltaic properties, density functional theory studies were conducted. Besides, important parameters such as open-circuit voltage, light harvesting efficiency, and band gap energy of the dye sensitizers were calculated and discussed. The theoretically calculated open-circuit voltage (Voc) values ranged from 1.28 to 2.04 eV, while the light-harvesting efficiency (LHE) values varied from 0.11 to 0.22. Indeed, this theoretical research could guide chemists to synthesize effective dyes for DSSCs. [ABSTRACT FROM AUTHOR]

Polymorphism plays a pivotal role in generating a range of crystalline materials with diverse photophysical and mechanical attributes, all originating from the same molecule. Here, we showcase two distinct polymorphs: green (GY) emissive and orange (OR) emissive crystals of 5′‐(4‐(diphenylamino)phenyl)‐[2,2′‐bithiophene]‐5‐carbaldehyde (TPA‐CHO). These polymorphs display differing optical characteristics, with GY exhibiting thermally activated delayed fluorescence (TADF) and OR showing room temperature phosphorescence (RTP). Additionally, both polymorphic crystals display mechanical flexibility and optical waveguiding capabilities. Leveraging the AFM‐tip‐based mechanophotonics technique, we position the GY optical waveguide at varying lengths perpendicular to the OR waveguide. This approach facilitates the exploration of the interplay between TADF and RTP phenomena by judiciously controlling the optical path length of crystal waveguides. Essentially, our approach provides a clear pathway for understanding and controlling the photophysical processes in organic molecular crystals, paving the way for advancements in polymorphic crystal‐based photonic circuit technologies. [ABSTRACT FROM AUTHOR]

This research delves into the effects of 2D layers on the functionality of 3D perovskite using lock‐in amplifier‐based in situ surface photovoltage (SPV) and its phase spectroscopy, with an emphasis on elucidating the connection between the tuning of dipole moments and the photocurrent hysteresis. Conventionally, the SPV of a perovskite/hole transport layer is observed to diminish as positive bias escalates. However, this trend is reversed in the case of 3D perovskite samples, where an augmentation in SPV is noted under positive bias. Notably, 3D/2D perovskite structures initially show a decrease, then an increase in SPV as bias intensifies, a phenomenon more pronounced with larger dipole moments in 2D. However, there is no linear relationship between the dipole moment and the hysteresis factor. Furthermore, using in situ light‐chopping‐frequency‐modulated SPV and Kelvin Probe Force Microscopy, it is revealed that the dipole fields of 2D layers can hinder ion migration. This leads to efficient hole transfer and minimal photocurrent hysteresis in 3D/2D perovskites, providing strong evidence for the underlying cause of hysteresis. Additionally, these findings suggest intricate interplays among the external electric field, interface dipole moments, and surface photovoltaics, offering significant insights into perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

An efficient I2 (10 mmol %)/H2O2 mediated oxidative formal [4+1] cyclization of 2‐pyridinemethylamine or o‐phenylenediamine (2‐aminobenzenethiol) with benzaldehyde via C−N bond formation has been developed. This strategy provides a straightforward approach to imidazo[1,5‐a]pyridines, iodo‐substituted imidazo[1,5‐a]pyridines and benzimidazole (benzothiazole) derivatives in yields ranging from 60 % to 98 %, respectively. Several heterocyclic products exhibit promising blue luminous performance with satisfactory fluorescence quantum yields of up to 64 %, large Stokes shifts, and a longer lifetime (7.35 ns). The band gap energies obtained from DFT are also consistent with the absorption spectra. [ABSTRACT FROM AUTHOR]

Here, we describe a set of coupled experimental and theoretical analyses. The introduction of one and two additional cyano groups in the carboheptahelicene backbone enhance its electron‐accepting properties. New carboheptahelicene derivatives are synthesized, and relevant characterizations of structural features, photophysical and electrochemical properties, and structure‐property relationships are described. This present work concerns the use of the density functional theory (DFT) to highlight the structural and the optoelectronic properties of carboheptahelicene derivatives and comparing the obtained findings with the experimental ones. The experimental and theoretical spectra (UV‐Vis absorption and photoluminescence) provide excellent concurrence. Afterward, molecular structures, structural parameters, molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of frontier molecular orbitals (FMOs) are constructed. Some other optoelectronic parameter including electron affinity (EA), ionization potential (IP), and some reactive descriptor such as chemical potential (μ), global hardness (η), electronegativity (χ) and the overall electrophilicity index (ω) are determined and indicating its potential uses as an active layer in optoelectronic efficient devices. The topological methods such as electron localization function (ELF), localization orbital locator (LOL) and the reduced density gradient method (RDG) were also conducted to clarify the strengths and kinds of interactions. [ABSTRACT FROM AUTHOR]

A new coordination polymer {[Cd(C12H13O5)2(4,4′-bpy)(H2O)2]}n (Cd-Tmca-bpy) was constructed with trans-2,3,4-Trimethoxycinnamic acid (HTmca) and 4,4′-Bipyridine (4,4′-bpy) ligands. This complex was structurally characterized on the basis of elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction and thermogravimetric analyses. X-ray crystallography revealed that the complex was monoclinic, space group C2/c. The Cd(II) ion in the complex was six coordinated, adopting an octahedron geometry. The neighboring Cd(II) ions linked linear ligand 4,4′-bpy molecules to form an infinite 1D chain. The 1D chain was further interlinked by O–H···O and C–H···O hydrogen bonds, resulting in a 3-D supramolecular framework. Meanwhile, the photoluminescence spectrum of the Cd(II) complex at room temperature exhibited an emission maximum at 475 nm. Using the time-dependent density functional theory (TD-DFT) method, the electronic absorption spectra of the Cd(II) complex was predicted. A good agreement was achieved between the predicted spectra and the experimental data. Bioactivity studies showed that the complex exhibited significant inhibition halos against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). [ABSTRACT FROM AUTHOR]

Quinazolines are biologically potent heterocyclic compounds; however, their synthesis poses high challenges. In this present study, we have developed an inexpensive cobalt metal‐catalyzed acceptorless dehydrogenative pathway for the sequential synthesis of alkenylated quinazolines from benzhydrol via dehydrogenation, cyclization, and subsequent dehydrogenative sp3 C−H functionalization. This transformation holds potential owing to its commercially available key starting materials, good functional tolerance, moderate reaction conditions, environmental friendliness, and applicability for gram‐scale synthesis. Furthermore, the synthetic utility of the synthesized derivatives has been explored through various reactions, including reduction, halogenation, methoxylation, Michael addition, and spiro cyclization. Additionally, the photophysical properties indicate that the nitrogen atom of the synthesized derivatives readily undergoes a reversible protonation, leading to significant changes in colour. This characteristic presents an opportunity for the creation of pH sensors with colourimetric capabilities. [ABSTRACT FROM AUTHOR]

A novel bromothiophene‐functionalized BF2‐curcuminoid (BTC‐BF2) is synthesized by Knoevenagel condensation reaction. The structure of BTC‐BF2 is determined by 1H‐nuclear magnetic resonance (1H NMR), 13C‐nuclear magnetic resonance (13C NMR), and high‐resolution mass spectrometry (HRMS). Moreover, a nearly coplanar single crystal structure is successfully obtained and form a mesh structure through intermolecular multiple C─H···F hydrogen bond interactions. As expected, as‐prepared BTC‐BF2 exhibits solvent‐dependent photophysical properties in solvents with different polarity and an intense red solid‐state fluorescence. Density functional theory calculations further verify the relationships between its intrinsic electronic features and the photophysical properties. For its potential application aspect, BTC‐BF2 shows a certain ability to generate singlet oxygen under irradiation with 530 nm green light. Moreover, BTC‐BF2 can be utilized as versatile building block to construct novel far‐red or NIR BF2‐curcuminoid complexes for widely biological applications. [ABSTRACT FROM AUTHOR]

We report the facile synthesis of asymmetric perylene diimides (asym−PDIs) using readily available reagents, demonstrating their distinct photoluminescent properties. In CHCl3, asym−PDIs exhibit higher solubility compared to traditional perylene dyes, of which solubilities can be varied by substituent selections. Among them, UV‐vis absorption spectra of CPE in CHCl3 solution displayed no aggregate peaks in the ground state, maintaining high photoluminescent quantum yields. Also, CPE can be readily dispersed into poly(methyl methacrylate) PMMA (CPE−PMMA), forming thin films without aggregate formation. Importantly, the emission color of CPE−PMMA thin films significantly changes with the addition of polycyclic aromatic hydrocarbons (PAHs). These color changes should be strongly correlated with the HOMO level of the added PAHs. [ABSTRACT FROM AUTHOR]

This study delves into the intricate electronic and photophysical properties of copper (II) complexes and their ligands, shedding light on their behavior under varying conditions. UV–Vis absorption spectroscopy unveils significant insights, revealing absorption peaks attributed to ligand–metal charge transfer transitions (LMCT) and π → π* transitions of C = N bonds. The solvent’s polarity dictates the absorption peak positions, indicating a pronounced solvatochromic effect. Molar extinction coefficients underscore the complexes’ high absorption efficiency across different solvents. Density Functional Theory (DFT) calculations provide a theoretical framework, elucidating electronic transitions observed experimentally. While HL1 exhibits a single peak, HL2 displays two peaks, findings supported by calculated transition energies and oscillator strengths.Moreover, the oxidation processes of copper complexes with iodide salt and triethylamine unveil favorable electron transfer mechanisms, as corroborated by cyclic voltammograms and free energy change values. Photolysis experiments underpin the complexes’ behavior under light irradiation, revealing reversible photoreduction processes and the formation of novel photoproducts. Notably, the addition of triethylamine influences photolysis kinetics, elucidating complex interactions. Furthermore, fluorescence experiments unveil the fluorescent behavior of bidentate copper (II) complexes and their ligands. Fluorescence emission peaks, observed around 475–550 nm for complexes and 400–550 nm for ligands, are influenced by solvent polarity, indicating solvent effects on fluorescence deactivation pathways. Overall, this comprehensive investigation provides valuable insights into the electronic and photophysical characteristics of copper (II) complexes, paving the way for their potential applications in diverse fields, including materials science, catalysis, and photochemistry.

Over the past decades, pyrazole has displayed significant importance in various areas of chemistry and industry owing to its unique nature, reactivity, and properties. Pyrazole is versatile compound with a wide range of applications in pharmaceuticals, agriculture, materials science, and various branches of science. Specifically, pyrazole C-3/C-5 carbaldehydes can be used as a building block in organic synthesis to create more valuable and bioactive molecules. In this context, pyrazole C-3/C-5 carbaldehydes may be explored for achieving pyrazole fused/linked heterocyclic skeletons by employing different organic transformations. The investigation of pyrazole C-3/C-5 carbaldehydes has resulted in the formation of a range of biologically potent heterocyclic structures, which include pyrazole C-3/C-5-based silicon derivatives, pyrazole C-3/C-5-based Schiff base derivatives, pyrazole C-3/C-5-based metal complexes, pyrazole C-3/C-5-based imidazo[1,2-a]azines, pyrazole C-3/C-5-based sulphur containing derivatives, and pyrazole C-3/C-5-based thioamide and amides, as well as other pyrazole fused/tethered polycyclic systems. Previous reports have shown that derivatives synthesized from the pyrazole C-3/C-5 carbaldehyde have demonstrated favourable biological uses like 5-HT3A receptor antagonists, allosteric inhibitors, insecticidal activity, antioxidant, antifungal, antiproliferative and antimicrobial. Pyrazole C-3/C-5 carbaldehydes have the potential to be highly utilized in the medical field as well as material science if studied judiciously. This review focuses on the exploration of pyrazole C-3/C-5 carbaldehydes towards the synthesis of highly diversified pyrazole-based molecular hybrids till 2023 and describes their promising utilization in the field of pharmaceutical science. [ABSTRACT FROM AUTHOR]

This study explores the synthesis of cyclopenta‐fused polyaromatic hydrocarbons (CP‐PAHs) via Pt‐catalyzed cyclization in water, focusing on the formation of fused pentagonal rings within heavily fused PAH frameworks. Utilizing platinum catalysts at lower temperatures (200‐260 °C) in water, led to the successful synthesis of singly cyclized CP‐PAHs. The reaction conditions facilitated the mono‐cyclization of substrates such as dibenzo[g,p]chrysene and its isomers, yielding the desired products while suppressing the formation of bis‐cyclized compounds. The use of Fe2O3 as an additive in conjunction with PtO2 was effective to suppress hydrogenation of the substrates and products. The products exhibited a redshift in UV‐visible absorption and photoluminescence bands due to a decrease in the HOMO−LUMO energy gap. These findings highlight the potential of Pt‐catalyzed cyclization for the controlled synthesis of CP‐PAHs, with implications for various applications in materials science. [ABSTRACT FROM AUTHOR]

The newly synthesized 5-arylidine-2-((5-nitropyridin-2-yl)imino)thiazolidin-4-ones 4a–4d were established in a good yield by Knoevenagel type of condensation with four diverse benzaldehyde derivatives branched with electron-donating moieties by refluxing in acetic acid. Meanwhile, investigate the photophysical properties of freshly synthesized conjugates 4a–4d, with an emphasis on their behavior in various solvents. Furthermore, differences in absorbance maxima among solvents indicated varying degrees of conjugation and electrical interactions within the molecules. Moreover, the cytotoxicity assessments demonstrated that, although these hybrids are typically less powerful than the conventional drug 5-Fu, they show extraordinary selectivity against certain cancer types. Notably, conjugate 4b showed strong activity against MCF-7 cells with an IC50 of 6.41 ± 0.21 μM, while conjugate 4d was very effective in HepG2 cells with an IC50 of 7.63 ± 0.05 μM. Molecular docking experiments confirmed these results by demonstrating effective interactions with the active region of the chosen protein. Given its promising pharmacokinetic profile, which includes intermediate solubility, good gastrointestinal absorption, and compliance with Lipinski's rule of five, conjugate 4d emerged as the most viable option for continued drug development. [ABSTRACT FROM AUTHOR]

The synthesis of two novel phthalonitrile derivatives (3–4) bearing ethynylcyclohex‐1‐ene and ethynylcyclohexane groups and two peripherally octa substituted zinc (II) phthalocyanines (5–6) were prepared. The synthesis of phthalonitrile derivatives was performed with Sonagashira coupling reaction by using palladium‐catalyzed. The newly synthesized compounds were characterized by using FT‐IR, NMR, mass, and UV‐Vis absorption spectroscopy techniques. Aggregation studies of 5 and 6 were performed in various organic solvents and different concentrations in tetrahydrofuran (THF). The photophysical studies of the Pcs were performed in THF to determine the effect of the alkyne groups on the fluorescence of the Pc ring. Substances showing fluorescence properties can be used in practical applications such as to create an image in microscopy. Fluorescence quantum yield (ΦF) and fluorescence lifetime (τF) of 5–6 were calculated. The fluorescence quenching studies of 5–6 were performed by adding the different concentrations of 1,4‐benzoquinone (BQ) to a constant concentration of the Pcs in THF and it was found that benzoquinone was an effective quencher. The values of the Stern‐Volmer constant (Ksv) and quenching constant (kq) of zinc phthalocyanines (5–6) were examined. All obtained results were compared with each other and with unsubstituted zinc Pc compound used as a reference. [ABSTRACT FROM AUTHOR]

Polybenzoxazines are a class of luminescent polymers that exhibit light emission properties, making them suitable for various applications. This manuscript presents the synthesis, characterization, and thermal behavior of a novel luminescent polybenzoxazine, named P‐BZ‐CP. The synthesis of P‐BZ‐CP involved a three‐stage process, starting with the formation of Bis‐OHOMe through the reaction of cyclopentanone and vanillin, followed by a Mannich condensation reaction with p‐toluidine to obtain the monomer M‐BZ‐CP. Thermal ring‐opening polymerization of M‐BZ‐CP at 250°C resulted in the synthesis of P‐BZ‐CP. Comprehensive characterization techniques, including NMR, FTIR, XRD, SEM, TGA, and DSC, were employed to analyze the structure and properties of both M‐BZ‐CP and P‐BZ‐CP. The thermal behavior of M‐BZ‐CP curing was investigated using DSC, highlighting the temperature‐dependent polymerization process. This work also provides insights into the photophysical properties of Bis‐OHOMe, M‐BZ‐CP, and P‐BZ‐CP, highlighting the role of molecular structure and concentration in determining absorption, excitation, and emission characteristics. The core benzylidene cyclopentanone chromophore contributes to the common absorption and emission features, while the additional functional groups in M‐BZ‐CP lead to concentration‐dependent photoluminescence behavior due to aggregation or excimer formation. These findings demonstrate the importance of understanding the structure–property relationships in designing optoelectronic materials with tunable photophysical properties. The findings demonstrate the successful synthesis and characterization of luminescent polybenzoxazines, providing valuable insights into their potential applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Copper halides, a new class of attractive and potential scintillators, have attracted tremendous attention in X‐ray imaging. However, the ambiguity surrounding their exciton properties and the unclear effect of crystal structure on their photophysical performance hinder an in‐depth understanding of their luminescence mechanism and their further application in the X‐ray imaging field. Herein, copper halide scintillators Cs3Cu2X5 (X = I, Br, and Cl) with a 0D crystal structure is prepared, and their photophysical properties and luminescence mechanism are revealed using both theoretical calculation and experimental verification. The small exciton Bohr diameter together with the high exciton binding energy can cause Cs3Cu2X5 to hold strongly confined excitons and lack quantum‐size effects. The 0D Cs3Cu2X5 materials exhibit a structural framework with a soft crystal lattice and Frenkel excitons with strong confinement effects, further resulting in a luminescence mechanism with self‐trapped excitons. In particular, Cs3Cu2I5 is demonstrated as an efficient scintillator with high radioluminescence efficiency and high spatial resolution of ≈106 µm in radiography, which is primarily attributed to strongly confined excitons to improve the radiative recombination probability of electron‐hole pairs. Overall, this work provides a pathway for developing 0D scintillators with strongly confined excitons to improve X‐ray imaging performance. [ABSTRACT FROM AUTHOR]

Triazoles are an important class of heterocyclic compounds due to their interesting structural features and versatile biological significance. In this regard, the present work highlights the synthesis of Cu(II)‐catalyzed 1,2,3‐trisubstituted triazoles through the cycloaddition of different chalcones with azides under neat methodology. A series of 16 triazole derivatives (3 a to 3 o) was prepared using 10 mol % Cu(II) complexes of 1,10‐phenanthroline and terpyridine‐based ligands as catalysts with moderate to excellent yields. All these derivatives were structurally analyzed by UV‐visible, infrared, 1H, 13C NMR and mass spectral data. The product, (4‐((4‐benzoyl‐5‐(4‐fluorophenyl)‐1H‐1,2,3‐triazol‐1‐yl) methyl)benzonitrile) (3 j) was structurally analyzed by single crystal XRD analysis. Also, the molecular structure of one of the catalysts, [Cu(Phen)2]2+(NO3−)2) was obtained by single crystal XRD analysis. Additional investigations of all these derivatives exhibited potential cytotoxic characteristics against MCF‐7 cancer cell lines. Among them, compounds 3 j, 3 i, 3 c, 3 d and 3 g facilitated the notable IC50 values. Moreover, the studies on the photophysical properties of synthesized derivatives showed the absorption bands in the range of 267–290 nm, depending on the nature of the substituent and the compounds 3 e and 3 f demonstrated the highest and lowest quantum yields as 0.05339 % and 0.01914 %, respectively. [ABSTRACT FROM AUTHOR]

A new curcuminoid molecule (3) has been designed and synthesized, containing a central -(CH2)2-COOH chain at the α carbon of the keto-enol moiety in the structure. The carboxylic acid group is added to react with exposed amino groups on silica oxide nanoparticles (nSiO2), forming an amide bond to attach the curcuminoid moiety to the nSiO2 covalently. The Kaiser test quantifies the functionalization degree, yielding 222 μmol of curcuminoid per gram of nanoparticles. The synthesized hybrid nanosystem, nSiO2-NHCO-CCM, displays significant emission properties, with a maximum emission at 538 nm in dichloromethane, similar to curcuminoid 1 (without the central chain), which emits at 565 nm in the same solvent. Solvent-induced spectral effects on the absorption and emission bands of the new hybrid nanosystem are confirmed, similar to those observed for the free curcuminoid (1). The new nanosystem is evaluated in the presence of kerosene in water, showing an emission band at 525 nm as a detection response. The ability of nSiO2-NHCO-CCM to change its fluorescence when interacting with kerosene in water is notable, as it overcomes the limitation caused by the insolubility of free curcuminoid 1 in water, allowing for the exploitation of its properties when connected to the water-stable nanosystem for future detection studies. [ABSTRACT FROM AUTHOR]

Multiheterocyclic inorganic–organic hybrid phosphazenes have robust inorganic ring systems with the stabilities of the phosphorus nitrogen skeleton and many different substituents bonded to the P atoms. In present study, unsymmetrical dispirocyclotriphosphazenes were prepared due to their potential to depict steric hindrance and electronic rearrangement in creating permanent chirality for certain conformational and configurational isomers. These isomers may have an effect on DNA bindings and activitiy against selected fungi and bacteria, remarkably. Herein, tetrachlorocyclotriphosphazenes (1 and 2) were reacted with 9-ethyl-N-methyl-3-carbazolyl-1,2-diaminoethane (3), 9-ethyl-N-ethyl-3-carbazolyl-1,2-diaminoethane (4) and 9-ethyl-N-methyl-3-carbazolyl-1,3-diaminopropane (5) to give the new unsymmetrical cis/trans-dispirocyclotriphosphazenes, [(ClBz/BzSpiro-6)R1(N3P3)(CzSpiro-n)R2]Cl2 (Cz: Carbazolyl; R1:Me R2:Me or Et; n = 5 or 6; trans 6a–11a and cis 6b–11b). Characterizations, chiralities, and photophysical and biological properties of the new compounds were examined. The molecular and crystal structures of cis-6b, cis-7b, trans-9a, cis-9b, trans-10a and cis-10b were determined by single crystal X-ray crystallography. The chiralities of these compounds with unsymmetrical spiro-architectures were confirmed by X-ray crystallography. These results were further proven by 31P NMR data recorded with the addition of a chiral solvent (CSA). Additionally, circular dichroism (CD) spectra also supported the results. Photophysical measurements indicate that these compounds show emission with lifetimes of approximately 5.6–5.9 ns. In addition, the bioactivities of some isomers were found to be different and quite high against some bacterial and yeast strains. Trans-8a was very active against B. cereus (MBC = 78.1 µM), while cis-6b, trans-9a and cis-9b were very active against the pathogenic yeast C. albicans (MFC = 156.3 µM). [ABSTRACT FROM AUTHOR]

A series of iridium(III) triimine complexes incorporating 2,2′:6′,2″-terpyridine (terpy) and 2,6-bis(thiazol-2-yl)pyridine (dtpy) derivatives were successfully designed and synthesized to investigate the impact of the peripheral rings (pyridine, thiazole) and substituents (thiophene, bithiophene, EDOT) attached to the triimine skeleton on their photophysical properties. The Ir(III) complexes were fully characterized using IR, 1H, elemental analysis and single crystal X-ray analysis. Their thermal properties were evaluated using TGA measurements. Photoluminescence spectra of [IrCl3L1–6] were investigated in solution at 298 and 77 K. The experimental studies were accompanied by DFT/TDDFT calculations. The photophysical properties of the synthesized triimine ligands and Ir(III) complexes were studied in detail by electronic absorption and emission. In solution, they exhibited photoluminescence quantum yields ranging from 1.27% to 5.30% depending on the chemical structure. The experimental research included DFT/TDDFT calculations. The photophysical properties of the synthesized triimine ligands and Ir(III) complexes were conducted using electronic absorption and emission techniques. In solution, they displayed photoluminescence quantum yields ranging from 1.27% to 5.30% depending on the chemical structure. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of terminal donors on the structures and photophysical properties, four donor (D1)-acceptor (A)-π bridge-donor (D2) prototype fluorophores were synthesized and characterized. Single crystal analysis indicated that changing the types of terminal donors (D2) would give rise to different frontier molecular orbitals and molecular packing modes, leading to their different emission behaviors in solid states. In dilute solution, the four D–A–π-D compounds displayed different absorption and emission behaviors in dilute solution with solvatochromism properties. Assisted by the quantum chemical calculations and wave function analysis, the essence of optical properties of four compounds were explored. The results indicated that changing the types of terminal donors (D2) can affect the structures and photophysical properties of such donor (D1)-acceptor (A)-π bridge-donor (D2) prototype fluorophores, which provided guidance to design new fluorophores. [ABSTRACT FROM AUTHOR]

2,3-Bis[5-(pyren-1-yl)thiophen-2-yl]quinoxalines and 2,3-bis{5-[4-(9H-carbazol-9-yl)phenyl]thiophen-2-yl}pyrazino[2,3-f][1,10]phenanthroline were synthesized. One- and two-photon absorption and emission of the compounds were studied, the cross sections of the two-photon absorption were found to be equal to 101–476 GM in THF. Fluorescent responses of pyrene-containing fluorophores and dipyrido-annelated quinoxaline to nitroaromatic compounds and metal cations, respectively, were investigated. [ABSTRACT FROM AUTHOR]

Methyl 4-(1,3a,6a-triazapentalen-3-yl)benzoate (TAP1) shows interesting properties as a small molecule fluorophore. In the search for post-functionalization methods, palladium-catalyzed arylation reactions were demonstrated. Direct CH arylation reactions of TAP1 with various aryl halides resulted in 3,6-diaryltriazapentalenes TAP4, although mostly in poor yields. Bromination of TAP1 followed by Suzuki coupling, on the other hand, requires a more delicate procedure, but gave arylated products with the same regiochemistry (TAP4) in moderate to good yields. The structure of 6-phenyltriazapentalene TAP4a was confirmed by crystallographic analysis. In addition, the effect of the C6 arylation on the fluorescent properties of 3-aryl-1,3a,6a-triazapentalenes was studied in dichloromethane at room temperature and in 2-methyltetrahydrofuran at 77 K, while the photophysical properties of two saponified derivatives were measured in acetonitrile. [ABSTRACT FROM AUTHOR]

The interaction of indotricarbocyanine dyes with lipid-transfer protein Ns-LTP1 in Dulbecco's phosphate-buffered saline (PBS) was studied. An orthophenylene bridge with a chlorine in the meso-position of the dye was shown to be ineffective as a linker for protein macromolecules without a free cysteine residue. The indotricarbocyanine dye was modified into the N-hydroxysuccinimide ester to obtain a complex of the indotricarbocyanine dye with the Ns-LTP1 protein. A complex of dye molecules with the Ns-LTP1 protein was obtained by mixing a two-phase system of the protein in PBS and the dye activated ester in 1,2-dichloroethane. The half-width of the absorption spectrum increased from 56 to 61 nm; the fluorescence decay time, from 0.3 to 0.5 ns; and the degree of polarization, from 27 to 31% upon formation of the complex. It was established that HCl at concentrations equivalent to its content in gastric juice (0.1–0.5%) led to irreversible destruction of the dye. Capsules that can withstand stomach acid and dissolve in the intestines could be used to treat erosive and ulcerative lesions with peroral administration of the complex. [ABSTRACT FROM AUTHOR]

Nanocrystalline ZnO samples with different average crystallite sizes in the range 12–89 nm and varying concentrations of native point defects are synthesized by the decomposition of carbonate precursor in air ambience at different temperatures, viz., 250, 450, 650 and 850 ∘ C. Analysis of Zn 2p and O 1s XPS spectra reveal the presence of elemental Zn, oxygen vacancies and adsorbed oxygen containing species in all samples. The optical band gap of the samples is in the range of 3.17–3.20 eV. Photoluminescence spectra of samples with smaller average crystallite sizes are dominated defect induced emission in the visible region while that of sample with larger average crystallite size is dominated by the band edge emission in the UV region. PL emission spectra reveals the presence of native point defects, V O + , V O + + , Zn i and O i , the relative contribution of which vary with the synthesis temperature. Photocurrent response increases with an increase in average crystallite size. The sample with largest average crystallite size (89 nm) exhibits better photocatalytic activity among the samples with better efficiency (40 in minutes), rate constant ( k = 10 × 10 - 2 min - 1 ) and reusability (93% degradation in 5 cycles). The degradation kinetics under superoxide and hydroxyl scavengers reveals that the degradation mechanism is dominated by the reaction of hydroxyl radicals. Larger average crystallite size leads to better photonic absorption and charge carrier separation while trapping of free electrons in the defect induced energy levels in the forbidden gap leads to longer recombination time thereby improving the catalytic activity. [ABSTRACT FROM AUTHOR]

Six red-light-emitting Eu(III) complexes having a β-hydroxyketone as ligand and heterocyclic ring containing compounds as ancillary ligands were synthesized to explore their use in displays and optoelectronics. The coordinating behavior of complexes was determined by various techniques such as FTIR (Fourier transform infrared), 1H-NMR (Nuclear magnetic resonance), and 13C-NMR that establishes a bonding of ligand and ancillary ligand with the Eu(III) ion. Morphology and purity were investigated through XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDS (energy-dispersive X-ray spectroscopy) analyses that suggest semicrystalline and pure complex formation. Thermal analysis of complexes by TGA/DTG (thermogravimetric/derivative thermogravimetric) indicates that complexes are stable upto 200 ºC temperature making them suitable for use in display devices. Analysis of the photophysical properties was carried out in both solid and solution states using PL (photoluminescence) studies, color parameters, J–O (Judd–Ofelt) analysis and bandgap. Most emissive transition (5D0 → 7F2) is responsible for the red emission in the complexes. The CIE (Commission International de I'Eclairage) coordinates of complexes also indicate the red emission on UV excitation. The bandgap which was obtained in the range of 2.54–3.02 eV reveals the semiconducting behavior of complexes. Values of J–O parameters and Ω2 in the complexes reflect asymmetric chemical environment around Eu (III) and less covalence and the Ω4 indicates that complexes are less rigid. Bandgap calculated through DFT (density function theory) for complexes is in range of 2.37–2.77 eV, and intensity parameters (J–O), energy transfer rates, and spherical coordinates were determined by LUMPAC software. The computational data are in good harmony with the experimental data. Further biological aspects of complexes were studied using antioxidant and antimicrobial studies. [ABSTRACT FROM AUTHOR]

Two new monopyridyl‐based Anthracene and Pyrene ligands were synthesized and employed to design Ruthenium‐coordinated organometallic complexes, RuAnthra and RuPyrene, respectively. The ligands and their metal complexes were fully characterized by different analytical techniques, including multinuclear 1D‐ and 2D‐NMR, electrospray ionization‐mass spectrometry, UV–Vis, fluorescence spectroscopy, and elemental analysis. Furthermore, their photophysical properties were studied in different solvents with increasing polarity using UV–Vis and fluorescence spectroscopy, showing less or no significant solvolysis effect. The average emission lifetimes of the complexes were further determined using time‐resolved emission spectroscopy. Additionally, the ligands and their metal complexes showed excellent ability to generate singlet oxygen and can be useful for several important potential applications. [ABSTRACT FROM AUTHOR]

Metal–halide perovskite nanocrystals (NCs) have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications. Despite their exceptional optical properties, the impact of different synthetic strategies on the fundamental nature of NCs, such as nonradiative recombination centers, remains poorly understood. In this study, we investigated the photophysical properties of CsPbBr3 NCs synthesized using two distinct methods, hot injection and ligand-assisted reprecipitation, at the individual particle level. We observed different blinking behaviors under specific photoexcitation power densities and proposed, through intensity–lifetime analysis and Monte–Carlo simulations, that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels, which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs. Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs, with significant implications for their use in optoelectronic and other technological applications. [ABSTRACT FROM AUTHOR]

Abstract This research delves into the effects of 2D layers on the functionality of 3D perovskite using lock‐in amplifier‐based in situ surface photovoltage (SPV) and its phase spectroscopy, with an emphasis on elucidating the connection between the tuning of dipole moments and the photocurrent hysteresis. Conventionally, the SPV of a perovskite/hole transport layer is observed to diminish as positive bias escalates. However, this trend is reversed in the case of 3D perovskite samples, where an augmentation in SPV is noted under positive bias. Notably, 3D/2D perovskite structures initially show a decrease, then an increase in SPV as bias intensifies, a phenomenon more pronounced with larger dipole moments in 2D. However, there is no linear relationship between the dipole moment and the hysteresis factor. Furthermore, using in situ light‐chopping‐frequency‐modulated SPV and Kelvin Probe Force Microscopy, it is revealed that the dipole fields of 2D layers can hinder ion migration. This leads to efficient hole transfer and minimal photocurrent hysteresis in 3D/2D perovskites, providing strong evidence for the underlying cause of hysteresis. Additionally, these findings suggest intricate interplays among the external electric field, interface dipole moments, and surface photovoltaics, offering significant insights into perovskite optoelectronics.

An efficient metal-free, triflic acid-promoted intramolecular Friedel–Crafts-type carbocyclization of alkenylated biphenyl derivatives is discussed. This method provides an elegant route for the construction of 9,10-dihydrophenanthrenes of biological significance in good to excellent yields. The carbocyclization reaction is likely to proceeds via activation of terminal CC bond of alkenylated biphenyl derivatives followed by subsequent aromatic electrophilic substitution to give desired carbocyclic products. Single crystal X-ray diffraction analysis of compound 10d revealed that the crystals are packed in AB-AB layer packing, where the molecules are aligned in anti-parallel fashion. Notably, all of the synthesized 9,10-dihydrophenanthrenes exhibited blue to greenish yellow fluorescence with λmax = 418–481 nm range. The stokes shift, quantum yield and optical band gap of tricyclic products were computed using their absorption and emission spectra. A significant positive solvatochromic effect was observed for 9,10-dihydrophenanthrene derivative 10l, which is a characteristic of ICT interactions.

A series of luminescent bis-cyclometalated iridium complexes with 2,2′:6′,2″-terpyridine (tpy), [Ir(C^N)2(tpy)]PF6 (C^N = 2-phenylpyridinate (ppy) for 1; benzo[h]quinolinate (bzq) for 2; 1-phenylisoquinolinate (piq) for 3; and 2-phenylbenzothiazolate (pbt) for 4), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analyses reveal that the tpy ligands of 1–4 are coordinated to the iridium center in a bidentate fashion, and the uncoordinated pendant pyridine rings in the tpy ligands of 1–4 form intramolecular π-π stacking interactions with a phenyl moiety of C^N ligands. In addition, the pendant pyridine ring in the tpy ligand of 1 forms an intramolecular hydrogen bonding interaction, unlike in 2–4. Of interest, the photophysical properties of 1–4 are strongly influenced by the C^N ligands; 1 shows a luminescence band at 572 nm, with a short lifetime (τ) value of 80 nsec and a lower absolute luminescence quantum yield (Φ) of 3.72%, whereas 3 exhibits an intense luminescence band at 588 nm with a long τ value of 1965 nsec and a moderate Φ value of 9.57%. The density functional theory calculations revealed that the luminescence originates from the triplet metal–ligand to ligand charge transfer (3MLL′CT) excited state.