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Hypoxic tumor microenvironments pose significant challenges to the clinical translation of cancer photodynamic therapy (PDT). While heavy atom‐free Type‐I boron dipyrromethenes (BODIPYs) photosensitizers can alleviate this challenge by reducing oxygen dependency, but they remain scarce. Herein, heavy‐atom‐free α,meso‐linked bisBODIPYs were designed and synthesized. These bisBODIPYs exhibit remarkable red‐shifted emission (λemmax ~670 nm), large Stokes shifts (~4480 cm−1) and they are capable of producing both superoxide anion (O2⋅−) and singlet oxygen (1O2) in solution and cells. Additionally, they offer a wide PDT treatment window, ranging from 0.26 to 83.5 μM. Furthermore, these bisBODIPYs also demonstrate superior two‐photon fluorescence, promising for surgical navigation and integrating diagnosis with treatment. [ABSTRACT FROM AUTHOR]

We report a synthetic approach to π‐expanded [6]helicenes incorporating tropone and azocine units in combination with a 5‐membered ring, which exhibit intriguing structural, electronic, and chiroptical properties. The regioselective Beckmann rearrangement allows the isolation of helical scaffolds containing 8‐membered lactam, azocine, and amine units. As shown by X‐ray crystallographic analysis, the incorporation of tropone or azocine units leads to highly distorted [6]helicene moieties, with distinct packing motifs in the solid state. The compounds exhibit promising optoelectronic properties with considerable photoluminescence quantum yields and tunable emission wavelengths depending on the relative position of the nitrogen center within the polycyclic framework. Separation of the enantiomers by chiral high‐performance liquid chromatography (HPLC) allowed characterization of their chiroptical properties by circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy. The azocine compounds feature manifold redox chemistry, allowing for the characterization of the corresponding radical anions and cations as well as the dications and dianions, with near‐infrared (NIR) absorption bands extending beyond 3000 nm. Detailed theoretical studies provided insights into the aromaticity evolution upon reduction and oxidation, suggesting that the steric strain prevents the azocine unit from undergoing aromatization, while the indene moiety dominates the observed redox chemistry. [ABSTRACT FROM AUTHOR]

Structurally symmetric dyes using functionalized fluorenes and benzotriazole as the main building moieties have been synthesized and found to exhibit efficient dual-state emission (DSE) and interesting two-wavelength or dual amplified spontaneous emission (dual-ASE) behaviors in the solution phase, which may benefit the development of organic gain materials with dual-wavelength amplification. [ABSTRACT FROM AUTHOR]

A pair of novel chiral Zn(II) complexes coordinated by Schiff-base type ligands derived from BINOL (1,1'-bi-2-naphthol), R-/S-Zn, were synthesized. X-ray crystallography revealed the presence of two crystallographically independent complexes; one has a distorted trigonal-bipyramidal structure coordinated by two binaphthyl ligands and one disordered methanol molecule (molecule A), while the other has a distorted tetrahedral structure coordinated by two binaphthyl ligands (molecule B). Numerous CH···π and CH···O interactions were identified, contributing to the formation of a 3-dimensional rigid network structure. Both R-/S-Zn exhibited fluorescence in both CH2Cl2 solutions and powder samples, with the photoluminescence quantum yields (PLQYs) of powder samples being twice as large as those in solutions, indicating aggregation-induced enhanced emission (AIEE). The AIEE properties were attributed to the restraint of the molecular motion arising from the 3-dimensional intermolecular interactions. CD and CPL spectra were observed for R-/S-Zn in both solutions and powders. The dissymmetry factors, gabs and gCPL values, were within the order of 10-3 to 10-4 magnitudes, comparable to those reported for chiral Zn(II) complexes in previous studies. [ABSTRACT FROM AUTHOR]

Dibenzothiophene (DBT) bridged bis‐dipyrromethane was synthesized by treating readily available 4,6‐di(p‐formylphenyl) dibenzothophene with pyrrole under acid catalyzed conditions. The DBT bridged bis‐dipyrromethane was further oxidized with DDQ to afford the DBT bridged bis‐dipyrrin which was used as a ligand to prepare DBT bridged bis‐BODIPY, bis‐Ni(II) dipyrrin and bis‐Pd(II) dipyrrin complexes by treating the ligand with BF3 ⋅ Et2O, Ni(acac)2 and Pd(acac)2 respectively under mild reaction conditions. The DBT‐bridged bis‐BODIPY and bis‐metal dipyrrin complexes were thoroughly characterized and studied by HR‐MS, 1D & 2D NMR, absorption, fluorescence, cyclic voltammetry and DFT techniques. The bis‐BODIPY and bis‐Pd(II) dipyrrin showed highly intense absorption band at ~500 nm along with one low intense absorption band at 340 nm whereas the bis‐Ni(II) dipyrrin complex showed slightly broadened blue shifted high intense band at 490 nm along with one additional band at 426 nm. The bis‐BODIPY was fluorescent with fluorescence band at 524 nm and quantum yield of 0.031 whereas bis‐M(II) dipyrrin complexes were nonfluorescent. DFT optimized structures revealed that the BODIPY units are more planar with the dibenzophene moiety in bis‐BODIPY with an angle of ∼5.68°. However, in 3‐Pd and 3‐Ni, the M(II)‐dipyrrin units are much more deviated from the dibenzothiophene plane with an angle of 12.81°–14.23°. [ABSTRACT FROM AUTHOR]

The ternary complexes of the zinc(II), [Zn(met)(gly)(Cl)2] (1), and [Zn(met)(hist)(Cl)2] (2) are synthesized and illustrated utilizing spectroscopic and analytical measurements, and the geometry of the complexes has been identified to be octahedral. The Coats Red fern approach was employed to enumerate the thermodynamic and kinetic variables for both the Zn(II) complexes' decomposition. The quantum chemical variables were estimated utilizing the molecular orbital conformations' energy distribution, which was derived from optimal geometric shapes to test the stabilization of both complexes. DNA‐binding investigations by UV–Vis absorption, fluorescence, and viscosity were all exploited to examine the bonding properties between Zn(II) complexes and ct‐DNA, and a groove mode of bonding was established. The interactions between complexes and BSA/HSA were investigated by employing absorption and emission spectroscopic methods. The results demonstrate that complexes have a powerful ability to diminish BSA and HSA luminescence intensity, and overall associating mode is predominantly a static quenching process. The cytotoxic effect of the two Zn(II) complexes was additionally examined in human breast adenocarcinoma (MCF‐7 and MDA‐MB‐231) cell lines by employing the MTT technique. The IC50 values for every cell line were derived. Each of the two complexes was functional in both cell lines. [ABSTRACT FROM AUTHOR]

The binding between a fluorescent water-soluble Zn(II) complex of {2-[N-(2-hydroxyethylammonioethyl) imino methyl] phenol} and calf thymus DNA (ct-DNA) was investigated using spectroscopic techniques. The complex was prepared and identified by FT-IR, and 1H NMR spectroscopies. The significant changes in the absorption and the circular dichroism spectra of ct-DNA in the presence of the Zn(II) complex implied the interaction between the Zn(II) complex and ct-DNA. Upon addition of ct-DNA, the fluorescence emission intensity of the Zn(II) complex was increased and indicated the interaction between the Zn(II) complex and ct-DNA was occurred. The binding constant values (Kb) resulted from fluorescence spectra clearly showed the Zn(II) complex affinity to ct-DNA. The fluorescence studies also approved the static enhancement mechanism in the Zn(II) complex-DNA complexation process. The thermodynamic profile exhibited the exothermic and spontaneous formation of ct-DNA-Zn(II) complex system via hydrogen bonds and van der Waals forces. The competitive fluorescence investigation by methylene blue (MB), and Hoechst 33258 demonstrated that the Zn(II) complex could replace the DNA-bound Hoechst and bind to the minor groove binding site in ct-DNA. The viscosity changes were negligible, representing the Zn(II) complex binding to DNA via the groove binding mode. Molecular docking simulation affirmed that the Zn(II) complex is located in the minor groove of ct-DNA near the DG12, DA17, DA18, and DG16 nucleobases. [ABSTRACT FROM AUTHOR]

Selective recognition of fructosyl amino acids in water by arylboronic acid-based receptors is a central field of modern supramolecular chemistry that impacts biological and medicinal chemistry. Fructosyl valine (FV) and fructosyl glycyl histidine (FGH) occur as N-terminal moieties of human glycated hemoglobin; therefore, the molecular design of biomimetic receptors is an attractive, but very challenging goal. Herein, we report three novel cationic Zn-terpyridine complexes bearing a fluorescent N-quinolinium nucleus covalently linked to three different isomers of strongly acidified phenylboronic acids (ortho-, 2Zn; meta-, 3Zn and para-, 4Zn) for the optical recognition of FV, FGH and comparative analytes (D -fructose, Gly, Val and His) in pure water at physiological pH. The complexes were designed to act as fluorescent receptors using a cooperative action of boric acid and a metal chelate. Complex 3Zn was found to display the most acidic –B(OH)2 group (pKa = 6.98) and exceptionally tight affinity for FV (K = 1.43 × 105 M−1) with a strong quenching analytical response in the micromolar concentration range. The addition of fructose and the other amino acids only induced moderate optical changes. On the basis of several spectroscopic tools (1H, 11B NMR, UV-Vis, and fluorescence titrations), ESI mass spectrometry, X-ray crystal structure, and DFT calculations, the interaction mode between 3Zn and FV is proposed in a 1 : 1 model through a cooperative two-point recognition involving a sp3 boronate–diol esterification with simultaneous coordination bonding of the carboxylate group of Val to the Zn atom. Fluorescence quenching is attributed to a static complexation photoinduced electron transfer mechanism as evidenced by lifetime experiments. The addition of FGH to 3Zn notably enhanced its emission intensity with micromolar affinity, but with a lower apparent binding constant than that observed for FV. FGH interacts with 3Zn through boronate–diol complexation and coordination of the imidazole ring of His. DFT-optimized structures of complexes 3Zn–FV and 3Zn–FGH show a picture of binding which shows that the Zn-complex has a suitable (B⋯Zn) distance to the two-point recognition with these analytes. Molecular recognition of fructosyl amino acids by transition-metal-based receptors has not been explored until now. [ABSTRACT FROM AUTHOR]

The development of fluorescent materials that can act as sensors for the determination of metal ions in biological fluids is important since they show, among others, high sensitivity and specificity. However, most of the molecules that are used for these purposes possess a very low solubility in aqueous media, and, thus, it is necessary to adopt some derivation strategies. Clay minerals, for example, hectorite, as natural materials, are biocompatible and available in large amounts at a very low cost that have been extensively used as carrier systems for the delivery of different hydrophobic species. In the present work, we report the synthesis and characterization of a hectorite/phenanthroline nanomaterial as a potential fluorescent sensor for Zn ion detection in water. The interaction of phenanthroline with the Ht interlaminar space was thoroughly investigated, via both theoretical and experimental studies (i.e., thermogravimetry, FT-IR, UV-vis and fluorescence spectroscopies and XRD measurements), while its morphology was imaged by scanning electron microscopy. Afterwards, the possibility to use it as sensor for the detection of Zn2+ ions, in comparison to other metal ions, was investigated through fluorescent measurements, and the stability of the solid Ht/Phe/Zn complex was assessed by different experimental and theoretical measurements. [ABSTRACT FROM AUTHOR]

Melanoma, arguably the deadliest form of skin cancer, is responsible for the majority of skin-cancer-related fatalities. Innovative strategies concentrate on new therapies that avoid the undesirable effects of pharmacological or medical treatment. This article discusses the chemical structures of [(MTZ)2AgNO3], [(MTZ)2Ag]2SO4, [Ag(MCZ)2NO3], [Ag(MCZ)2BF4], [Ag(MCZ)2SbF6] and [Ag(MCZ)2ClO4] (MTZ—metronidazole; MCZ—miconazole) silver(I) compounds and the possible relationship between the molecules and their cytostatic activity against melanoma cells. Molecular Hirshfeld surface analysis and computational methods were used to examine the possible association between the structure and anticancer activity of the silver(I) complexes and compare the cytotoxicity of the silver(I) complexes of metronidazole and miconazole with that of silver(I) nitrate, cisplatin, metronidazole and miconazole complexes against A375 and BJ cells. Additionally, these preliminary biological studies found the greatest IC50 values against the A375 line were demonstrated by [Ag(MCZ)2NO3] and [(MTZ)2AgNO3]. The compound [(MTZ)2AgNO3] was three-fold more toxic to the A375 cells than the reference (cisplatin) and 15 times more cytotoxic against the A375 cells than the normal BJ cells. Complexes of metronidazole with Ag(I) are considered biocompatible at a concentration below 50 µmol/L. [ABSTRACT FROM AUTHOR]

Similarity of nitroimidazole and nitrofuran antibiotics in molecular structure and photophysical properties makes them difficult to distinguish via luminescence sensing technology. Herein, this is solved by a dye-encapsulated lanthanide metal--organic framework luminescent sensor. [ABSTRACT FROM AUTHOR]

Cosmic infrared emission and absorption spectra often carry a well-defined and invariant 6.2  |$\mu \rm m$| band that has been proposed to emanate from very small dust grains that may carry polyaromatic hydrocarbons. Hemoglycin, a well-defined polymer of glycine that also contains iron, has been found in meteorites of the primordial CV3 class and therefore originated in the solar protoplanetary disc. Here, we suggest that the polymer hemoglycin should also be considered as a source of the cosmic 6.2  |$\mu{\rm m}$| emission and absorption. In quantum calculations, the principal amide I infrared absorption band of hemoglycin is centred, before splitting, at 6.0 |$\mu\rm m$|⁠. Multiple hemoglycin polymers interact to split amide I into the strong (a -) band in the region of 6.2 |$\mu\rm m$| and the much weaker (a +) band in the region of 5.8 |$\mu\rm m$|⁠. Experimentally, these two components are seen in extracts of the Sutter's Mill meteorite and in stromatolite ooid. The two 11-mer glycine antiparallel chains of hemoglycin have an exact structural analogue in antiparallel poly- l -lysine beta sheet crystals which in the laboratory have an (a -) absorption peak at 6.21 |$\mu\rm m$|⁠. This wavelength coincidence, the demonstrated propensity of hemoglycin 4.9 nm rods to form accreting lattice structures, and its proven existence in the solar protoplanetary disc suggest that the cosmic 6.2 |$\mu\rm m$| emission and absorption could be from small grains that are hemoglycin lattices or shell-like vesicles carrying internal organic molecules of various types. Calculated hemoglycin ultraviolet absorptions associated with iron in the molecule match the observed ultraviolet extinction feature at nominal 2175 Å. [ABSTRACT FROM AUTHOR]

In this work, we introduced a simple aggregation-induced emission enhancement (AIEE) sensor (PHCS) which can selectively detect and discriminate three environmentally and biologically imperative heavy metal ions (Cu2+, Co2+ and Hg2+) and a hazard class 1 categorized nitro-explosive picric acid (PA) in differential media. By virtue of its weak fluorescence attributes in pure organic medium owing to the synergistic operation of multiple photophysical quenching mechanisms, the molecular probe showcased highly selective 'TURN ON' fluorogenic response towards hazardous Hg2+ with a limit of detection (LOD) as low as 97 nM. Comprehensive investigation of binding mechanism throws light on the cumulative effect of probe-metal complexation induced chelation enhanced fluorescence (CHEF) effect and subsequent AIEE activation within the formed probe-metal adducts. Noteworthily, the probe (PHCS) can be readily used in real water samples for the quantitative determination of Hg2+ in a wide concentration range. In addition, the probe displayed modest colorimetric recognition performances to selectively detect and discriminate two essential heavy metal ions (Cu2+ and Co2+) with a LOD of 96 nM and 65 nM for Cu2+ and Co2+ respectively, in semi-aqueous medium. Intriguingly, based on high photoluminescence efficiency, the AIEE active nano-aggregated PHCS displayed a remarkable propensity to be used as a selective and ultra-sensitive 'TURN-OFF' fluorogenic chemosensor towards PA with LOD of 34.4 ppb in aqueous medium. Finally, we specifically shed light on the interaction of PHCS hydrosol towards PA using some unprecedented techniques, which helped uncover new photophysical insights of probe-explosive molecule interaction. We shed light on novel photophysical insights toward unique multifunctional sensory aptitude of a simple aggregation-induced emission enhancement active organic functional molecule in differential media, enabling ultra-sensitive discriminative detection of toxic heavy metal ions and explosive molecule simultaneously. [ABSTRACT FROM AUTHOR]

In this study, we present a comprehensive investigation of 2-amino-4,6-diphenylnicotinonitriles (APNs, 1–6), including their synthesis, cytotoxicity against breast cancer cell lines, and photophysical properties. Compound 3 demonstrates exceptional cytotoxicity, surpassing the potency of Doxorubicin. The fluorescence spectra of the synthesized 1–6 in different solvents reveal solvent-dependent shifts in the emission maximum values, highlighting the influence of the solvent environment on their fluorescence properties. A quantum chemical TD-DFT analysis provides insights into the electronic structure and fluorescence behavior of 1–6, elucidating HOMO-LUMO energy gaps, electronegativity values, and dipole moments, contributing to a deeper understanding of their electronic properties and potential reactivity. These findings provide valuable knowledge for the development of APNs (1–6) as fluorescent sensors and potential anticancer agents. [ABSTRACT FROM AUTHOR]

DNA-stabilized silver nanoclusters with 10 to 30 silver atoms are interesting biocompatible nanomaterials with intriguing fluorescence properties. However, they are not well understood, since atom-scale high level theoretical calculations have not been possible due to a lack of firm experimental structural information. Here, by using density functional theory (DFT), we study the recently atomically resolved (DNA)2–Ag16Cl2 nanocluster in solvent under the lowest-lying singlet (S1) and triplet (T1) excited states, estimate the relative emission maxima for the allowed (S1 → S0) and dark (T1 → S0) transitions, and evaluate the transient absorption spectra. Our results offer a potential interpretation of the recently reported transient absorption and dual emission of similar DNA-stabilized silver nanoclusters, providing a mechanistic view on their photophysical properties that are attractive for applications in biomedical imaging and biophotonics. [ABSTRACT FROM AUTHOR]

DNA-stabilized silver nanoclusters with 10 to 30 silver atoms are interesting biocompatible nanomaterials with intriguing fluorescence properties. However, they are not well understood, since atom-scale high level theoretical calculations have not been possible due to a lack of firm experimental structural information. Here, by using density functional theory (DFT), we study the recently atomically resolved (DNA)2–Ag16Cl2 nanocluster in solvent under the lowest-lying singlet (S1) and triplet (T1) excited states, estimate the relative emission maxima for the allowed (S1 → S0) and dark (T1 → S0) transitions, and evaluate the transient absorption spectra. Our results offer a potential interpretation of the recently reported transient absorption and dual emission of similar DNA-stabilized silver nanoclusters, providing a mechanistic view on their photophysical properties that are attractive for applications in biomedical imaging and biophotonics. [ABSTRACT FROM AUTHOR]

Aiming at the construction of novel stimuli‐responsive fluorescent system with precisely tunable emissions, the typical 9,14‐diphenyl‐9,14‐dihydrodibenzo[a, c]phenazine (DPAC) luminogen with attractive vibration‐induced emission (VIE) behavior has been introduced into [2]rotaxane as a stopper. Taking advantage of their unique dual stimuli‐responsiveness towards solvent and anion, the resultant [2]rotaxanes reveal both tunable VIE and switchable circularly polarized luminescence (CPL). Attributed to the formation of mechanical bonds, DPAC‐functionalized [2]rotaxanes display interesting VIE behaviors including white‐light emission upon the addition of viscous solvent, as evaluated in detail by femtosecond transient absorption (TA) spectra. In addition, ascribed to the regulation of chirality information transmission through anion‐induced motions of chiral wheel, the resolved chiral [2]rotaxanes reveal unique switchable CPL upon the addition of anion, leading to significant increase in the dissymmetry factors (glum) values with excellent reversibility. Interestingly, upon doping the chiral [2]rotaxanes in stretchable polymer, the blend films reveal remarkable emission change from white light to light blue with significant 6.5‐fold increase in glum values up to −0.035 under external tensile stresses. This work provides not only a new design strategy for developing molecular systems with fluorescent tunability but also a novel platform for the construction of smart chiral luminescent materials for practical use. [ABSTRACT FROM AUTHOR]

Supramolecular organic frameworks (SOFs) are widely used for biological detection and drug delivery. In this study, a SOF system was fabricated through the self-assembly of photosensitive triarylboron (TAB), TAB-6-methyl, and CB[8]. The maximum fluorescence emission of TAB-6-methyl was greatly enhanced and red-shifted from 560 nm to 610 nm after SOF formation. The SOF can specifically respond to a microRNA by dissembling and then combining with microRNA, which is accompanied by a fluorescence shift from 610 nm to 560 nm, thus providing a ratiometric readout for microRNA detection. The photosensitivity of TAB-6-methyl can be further improved by forming a SOF, which can be used in photodynamic therapy. By constructing another guest molecule, TAB-5-1-cRGD, we successfully embedded cRGD in the SOF system to improve its tumor-targeting ability. Moreover, we used this SOF system as a fluorescence imaging probe for targeted tumor imaging and as a drug carrier system for loading DOX to achieve combined photodynamic and chemotherapy treatment of tumors. [ABSTRACT FROM AUTHOR]

Diagram of the fabrication process for multicolor emitting SQDs and the mechanism of their applications. [Display omitted] Sulfur quantum dots (SQDs) have aroused widespread interest from researchers in a wide range of fields due to their excellent photoluminescent properties. Ethylenediamine, diaminopropane and butanediamine were used as precursor amine raw materials to interact with sublimated sulfur to synthesize SQDs with blue, cyan and green fluorescence emission, respectively. Multicolour emitting SQDs were first prepared via sulfur-amine interactions. Further characterization and calculations showed that the precursor amine substances could alter growth size and band gap energy of SQDs to allow for a wider absorption and fluorescence transfer to long wavelength emission region, resulting in tunable fluorescence emission. In terms of application, the excellent down-conversion properties of SQDs were utilized to obtain highly transparent and flexible photoblocking films by blending SQDs with polyvinyl alcohol matrixes, achieving a blocking of light in UV region of up to 99.69 %. In addition, we constructed an encoded storage microarray based on standard 8-bit ASCII character binary codes using BSQDs and GSQDs to store and encrypt important information. Finally, GSQDs-based fluorescent sensors were designed to achieve fluorescent trace detection of o-nitrophenols with limits of detection as low as 2.54 μM. The multicolor emitting SQDs prepared in this work have great potential for applications in analytical detection, optical anti-counterfeiting and light blocking. [ABSTRACT FROM AUTHOR]

Small organic molecules which can emit fluorescence with tunable dual emission bands are significant for fundamental research and broad applications. In this work, two binaphthyl based arylacrylonitrile derivatives with pyrene and triphenylamine unit (BiNp‐Py and BiNp‐TPA) were designed and synthesized, respectively, featuring chiral backbone and dual AIE‐active cyanostyrene‐linked chromophores. Excellent fluorescence emissions in a range of solution and solid states were observed with high quantum yields, indicative of the solvatochromism and mechanochromism. More interestingly, dual emission bands were found and tunable by the water fraction in THF, and speculatively attributed to the balancing of intramolecular charge transfer (ICT) and locally excited (LE) emission in solution and aggregate states. Furthermore, the potential application in anti‐counterfeiting ink was also explored, indicating the very low concentration (5 ppm) for sufficient distinguishable vision and small colour migration (28 nm) for printing on the filter. The present work provides a new strategy to design organic luminescent structure having widely fluorescent emissions in dual states and a valuable reference for the study of chiral optical materials. [ABSTRACT FROM AUTHOR]

Almost all types of proteins in biology are composed of L -amino acids, and very few contain D -amino acids. Therefore, chiral recognition, especially for the detection of L -amino acids, is of great importance. In this work, luminescent zinc-doped carbon dots (Zn-CDs) were successfully synthesized through a one-step hydrothermal method using [Zn(EDA)3]Cl2 (EDA = ethylenediamine) complex as a precursor, exhibiting superior water stability, low cytotoxicity and good photobleaching stability. It can be used as an "on–off–on" fluorescence probe in aqueous solution to sequentially detect Fe2+ ions and enantiomeric L -Lysine (L -Lys) molecules with the corresponding limit of detection (LOD) of 0.092 and 0.204 μM, respectively. Also, the sequential on–off–on fluorescent changes of Zn-CDs upon the addition of Fe2+ and L -Lys can be applied in living cell imaging, as observed by the contrast of images in confocal microscopy. In addition, two distinct multi-input molecular logic gates, involving distinguishing the effect of L -Lys and D -Lys on the fluorescence of Zn-CDs, and the regulation of fluorescence quenching and recovery of Zn-CDs by Fe2+ ions and L -Lys are established. The Zn-CDs also exhibits a linearly temperature-dependent fluorescence performance with high temperature sensitivity (Sr) of 1.10% °C−1 in 10–90 °C, demonstrating its great potential for biological temperature sensing applications. This work provides a new strategy for exploring novel metal-doped carbon dots with outstanding biocompatibility and multifunctionality in biological applications. [ABSTRACT FROM AUTHOR]

A novel metal–organic framework (MOF) Zn-PBC (H2PBC = pyridine-3,5-bis(phenyl-4-carboxylic acid)) was designed and synthesized via a solvothermal reaction with the H2PBC ligand, and produced a strong fluorescence. The material exhibited good stability and an ideal luminescent property in water. In addition, it was found that Zn-PBC displayed a different fluorescent response to different types of amino acids, and the mechanism was investigated. This research might give insight to the interaction between MOFs and amino acids, which would provide a strategy to fabricate MOF-based sensors for biomolecules in future. [ABSTRACT FROM AUTHOR]

We present a robust approach to generate a continuously tunable, low phase noise, Hz linewidth and mHz/s stability THz emission in the 0.1 THz to 1.4 THz range. This is achieved by photomixing two commercial telecom, distributed feedback lasers locked by optical-feedback onto a single highly stable V-shaped optical cavity. The phase noise is evaluated up to 1.2 THz, demonstrating Hz-level linewidth. To illustrate the spectral performances and agility of the source, low pressure absorption lines of methanol and water vapors have been recorded up to 1.4 THz. In addition, the hyperfine structure of a water line at 556.9 GHz, obtained by saturation spectroscopy, is also reported, resolving spectral features displaying a full-width at half-maximum of 10 kHz. The present results unambiguously establish the performances of this source for ultra-high resolution molecular physics. The authors demonstrate a very stable yet broadly tunable photonic THz source, characterized from 2 GHz to 1.4 THz. A very narrow Lamb dip feature is observed in a water absorption line, showcasing its potential for sub-kHz resolution spectroscopy. [ABSTRACT FROM AUTHOR]

Near‐Infrared (NIR) fluorescence imaging with the advantages of deep tissue penetration and minimum background, has been widely employed and developed in the study of biological applications. However, small Stokes shifts, difficulty in optical tuning, and pH sensitivity are still the major limitations faced by current NIR dyes. To solve these problems, we rationally designed a pH insensitive amino‐tunable NIR oxazine fluorophore DQF‐NH2, which exhibited large Stokes shift (125 nm) accompanied with NIR excitation/emission due to the introduction an asymmetrical alternating vibronic feature. By benefiting from the excellent photophysical properties of DQF‐NH2, we have successfully constructed the probe DQF‐NH2‐LAP with the ability to detect endogenous LAP. Bioimaging assays demonstrated that DQF‐NH2‐LAP can not only effectively detect LAP in living cells, but also was successfully applied to image tumor tissue in vivo. We anticipate that the functionalizable dye DQF‐NH2 may be a potential new NIR dye platform with an optically tunable group for the development of future desirable probes for bioimaging. [ABSTRACT FROM AUTHOR]

Some original poly(tetrasubstituted imidazole)s incorporating different units were synthesized and characterized. These materials were obtained via a cascade polycondensation process assisted by microwave irradiation that was developed by our team. This time, we integrated two well-known chromophore structures into the macromolecular backbone, which were benzothiadiazole (BTD) and diketopyrrolopyrrole (DKPP). These new polymers were fully characterized: their chemical structures were confirmed using NMR spectroscopy and their thermal, optical and electrochemical properties were investigated and compared with a reference polymer containing a phenyl spacer instead of the mentioned chromophore units. These materials were found to exhibit a large Stokes shift of up to 350 nm. Furthermore, a polymer presenting large absorption on the UV–visible range and an emission close to the near-infrared region was obtained by coupling the mentioned moieties. According to the established properties of this latter polymer, it presents a potential for applications in biological imaging or optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this article, for the first time, TG-DSC and TG-FTIR investigations of potential pharmaceutics, i.e., analgesic and anticancer active annelated triazinones (1–9) have been presented. The thermal behaviour of these molecules was established in oxidative and inert conditions. The solid–liquid phase transition for each compound (1–9) was documented by one sharp DSC peak confirming the high purity of each sample studied. All the molecules were characterised in terms of calorimetric changes and mass changes during their heating. They revealed high thermal stability in oxidative and inert conditions. The observed tendency in thermal stability changes in relation to a substituent present at the phenyl moiety was found to be similar in air and nitrogen. It was confirmed that annelated triazinones 1–9 were stable up to a temperature range of 241–296 °C in air, and their decomposition process proceeded in two stages under oxidative conditions. In addition, it was established that their thermal stability in air decreased in the following order of R at the phenyl moiety: 4-Cl > 3,4-Cl2 > H > 3-Cl > 4-CH3 > 2-CH3 > 3-CH3 > 2-Cl > 2-OCH3. The volatile decomposition products of the investigated molecules were proposed by comparing the FTIR spectra collected during their thermogravimetric analysis in nitrogen with the spectra from the database of reference compounds. None of annelated triazinones 1–9 underwent any polymorphic transformation during thermal studies. All the compounds proved to be safe for erythrocytes. In turn, molecules 3, 6, and 9 protected red blood cells from oxidative damage, and therefore may be helpful in the prevention of free radical-mediated diseases. [ABSTRACT FROM AUTHOR]

In this article for the first time the quantum calculations of 3-methyl-4-oxoimidazo[5,1-d][1,2,3,5]tetrazine-8-carboxamide (Temozolomide) in HCM-Cellulose Substrate are evaluated using the B3LYP/6-31G level of theory. The non-bonded interaction effects of the molecule Temozolomide, HCM-Cellulose on the electronic properties, chemical shift tensors and natural charge have also been detected. Natural bond orbital analysis (NBO) suggests that Temozolomide as an electron donor and HCM-Cellulose acted as an electron acceptor in the Temozolomide/HCM-Cellulose complex. The electronic spectra of the Temozolomide drug and Temozolomide/HCM-Cellulose complex in were calculated by Time-Dependent Density Functional Theory (TD-DFT) for the investigation of the adsorption effect of the Temozolomide drug over HCM-Cellulose on maximum wavelength. As a result, the feasibility of using HCM-Cellulose to deliver Temozolomide to diseased cells has been established. [ABSTRACT FROM AUTHOR]

Since the occurrence of tumours is closely associated with the telomerase function and oncogene expression, the structure of such enzymes and genes are being recognized as targets for new anticancer drugs. The efficacy of several ligands in telomerase inhibition and in the regulation of genes expression, by an effective stabilisation of G-quadruplexes (G4) DNA structures, is being considered as a promising strategy in cancer therapies. When evaluating the potential of a ligand for telomerase inhibition, the selectivity towards quadruplex versus duplex DNA is a fundamental attribute due to the large amount of double-stranded DNA in the cellular nucleus. This study reports the evaluated efficacy of three tetracationic opp-dibenzoporphyrins, a free base, and the corresponding zinc(II) and nickel(II) complexes, to stabilise G4 structures, namely the telomeric DNA sequence (AG3(T2AG3)3). In order to evaluate the selectivity of these ligands towards G4 structures, their interaction towards DNA calf thymus, as a double-strand DNA sequence, were also studied. The data obtained by using different spectroscopic techniques, such as ultraviolet-visible, fluorescence, and circular dichroism, suggested good affinity of the free-base porphyrin and of its zinc(II) complex for the considered DNA structures, both showing a pattern of selectivity for the telomeric G4 structure. A pattern of aggregation in aqueous solution was detected for both Zn(II) and Ni(II) metallo dibenzoporphyrins and the ability of DNA sequences to induce ligand disaggregation was observed. [ABSTRACT FROM AUTHOR]

Silicon nanocrystals are intriguing materials for biomedical imaging applications because of their unique optical properties and biological compatibility. We report a new surface functionalization route to synthesize biological buffer soluble and colloidally stable silicon nanocrystals, which is enabled by surface boron doping. Harnessing the distinctive Lewis acidic boron surface sites, postsynthetic modifications of plasma synthesized boron doped nanocrystals were carried out with polyethylene glycol (PEG-OH) ligands in dimethyl sulfoxide under photochemical conditions. The influence of PEG concentration, PEG molecular weight, and boron doping percentage on the nanocrystal solubility in a biological buffer has been investigated. The boron doping facilitates the surface functionalization via two probable pathways, by providing excellent initial dispersiblity in polar solvents and providing available acidic boron surface sites for bonding. These boron doped silicon nanocrystals have nearly identical absorption features as intrinsic silicon nanocrystals, indicating that they are promising candidates for biological imaging applications. [ABSTRACT FROM AUTHOR]

The photosynthetic tetrapyrroles and their catabolic products (phyllobilins) share similar structural features in the southern rim encompassing rings C–E with variation in the degree of saturation including a dihydrodipyrrin (chlorophyll a and bacteriochlorophyll a), a dipyrromethane (phylloleucobilin), and a dipyrrin (chlorophyll c). Here, a direct, two-step route to southern rim structures was examined. The Knoevenagel condensation of a pyrrole bearing a β-ketoester at the 3-position with a pyrrole-2-carboxaldehyde formed the dipyrrole-substituted propenone, which upon Nazarov cyclization gave the dipyrromethane-type southern rim containing the annulated, isocyclic ring. In this manner, three southern rim structures (51–80%) were obtained that vary in the nature of the pyrrole substituents (H, methyl, carbomethoxy). Characterization by 1H NMR spectroscopy in each case revealed an expected mixture of trans/cis isomers (∼9 : 1 ratio). Several derivatization processes (pyrrole acylation with trichloroacetic anhydride, ketone reduction with borohydrides) were examined. Analysis of one southern rim compound by single-crystal X-ray diffraction showed the trans configuration for the expected pair of enantiomers in the unit cell; a second compound gave the trans enantiomers as a conglomerate. The Knoevenagel–Nazarov route from relatively accessible pyrroles may provide new scaffolds for constructing tetrapyrrole architectures. [ABSTRACT FROM AUTHOR]

Tetrafluorocyclohexa-1,3-diene ring-containing tricyclic π-conjugated molecules are promising negative-dielectric-anisotropy guest species for vertical-alignment-type liquid-crystalline (LC) displays. Building on our previous work reporting the excellent photoluminescence (PL) properties of tricyclic π-conjugated molecules with central tetrafluorocyclohexa-1,3-diene rings, we herein synthesized four analogous molecules with terminal tetrafluorocyclohexa-1,3-diene rings from commercially available precursors and investigated the effects of substituent type and diene ring position on PL and LC properties using microscopic and spectroscopic methods. One of the prepared molecules exhibited a relatively planar molecular structure and formed herringbone-type aggregates via π/F and CH/π interactions instead of forming stacked aggregates via π/π stacking interactions, thus exhibiting relatively strong PL in solution and crystalline states. Moreover, the PL color of this compound depended on the electronic character of its terminal substituents along the long molecular axis. Of the four prepared species, two featured terminal ethyl groups and formed one or more LC phases. The PL properties of these phases indicated that the related phase transition induced changes in the aggregate structure, PL wavelength, and PL color. Our results expand the applicability of CF2CF2 moiety-containing tricyclic compounds as functional molecules for the fabrication of next-generation PL, LC, and PL-LC materials. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of anthracene‐containing twisted cyclo[2]dipyrrin 1 by utilizing a non‐planar building block, 1,5‐dipyrrylanthracene (1,5‐DPA). The non‐planar nature of the macrocycle enhanced the solubility and helped in structural characterization. Macrocycle 1 adopts a twisted 'figure of eight' conformation stabilized by strong intramolecular H‐bonding interactions and exists as a pair of helical enantiomers, as revealed by X‐ray crystallographic analysis. More importantly, the sterically locked structure enabled facile optical resolution using chiral HPLC. The (P,P) and (M,M) enantiomers show moderate chiroptical properties, such as absorption dissymmetry factors |gabs| in the order of 10−3, and luminescence dissymmetry factors |glum| of 3.8×10−3 and 2.9×10−3 at 702 nm, respectively. [ABSTRACT FROM AUTHOR]

The introduction of electron-withdrawing groups on 8(meso)-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8(meso)-pyridyl-BODIPYs bearing a 2-, 3-, or 4-pyridyl group was synthesized and functionalized with nitro and chlorine groups at the 2,6-positions. The 2,6-methoxycarbonyl-8-pyridyl-BODIPYs analogs were also synthesized by condensation of 2,4-dimethyl-3-methoxycarbonyl-pyrrole with 2-, 3-, or 4-formylpyridine followed by oxidation and boron complexation. The structures and spectroscopic properties of the new series of 8(meso)-pyridyl-BODIPYs were investigated both experimentally and computationally. The BODIPYs bearing 2,6-methoxycarbonyl groups showed enhanced relative fluorescence quantum yields in polar organic solvents due to their electron-withdrawing effect. However, the introduction of a single nitro group significantly quenched the fluorescence of the BODIPYs and caused hypsochromic shifts in the absorption and emission bands. The introduction of a chloro substituent partially restored the fluorescence of the mono-nitro-BODIPYs and induced significant bathochromic shifts. [ABSTRACT FROM AUTHOR]

Friedel‐Crafts acylation of dipyrromethane with cinnamoyl chloride was conducted to obtain dicinnamoyl dipyrromethane compounds 3 and 4. Both compounds were subsequently oxidized by DDQ to produce dicinnamoyl dipyrromethene ligands (DC‐1 and DC‐2). A large bathochromic shift compared to dipyromethene (D) was observed at 95 nm for DC‐1 and 67 nm for DC‐2. Both compounds showed remarkable chelation‐enhanced fluorescence (CHEF) upon addition of zinc(II) ions. Similar to the quadrupolar system, DC‐1 exhibited absorption and emission near the optical windows of the tissue. However, asymmetrical DC‐2 had a better "turn‐on" CHEF, with a fluorescence intensity that was 22 times higher than that of compound D. The DC‐2 ligand also showed a limit of detection (LOD) of up to 3.0×10−8 M and selectivity toward zinc(II) ions compared to alkali and alkaline earth metal ions. [ABSTRACT FROM AUTHOR]

Dipyrromethenes containing two pyrrole rings connected by one meso-carbon are versatile monoanionic bidentate ligands and form coordination complexes with many metals/nonmetals/metalloids. Dipyrroethenes containing one additional meso-carbon compared to dipyrromethenes have more space between coordinating pyrrole nitrogens and provide a good coordination environment but have not been explored as ligands in coordination chemistry. Dipyrroethenes are dianionic bidentate ligands and by suitable modifications, the coordination environment of dipyrroethenes can be changed further. Herein, we successfully synthesized α,α′-ditolylmethanone dipyrroethene which is a bipyrrolic tetradentate ligand with an ONNO ligand core and used it for the synthesis of novel Pd(II), Ni(II), and Cu(II) metal complexes by treating it with respective metal salts in CH2Cl2/CH3OH at room temperature. The X-ray crystallographic structure of the metal complexes showed that the M(II) ion was coordinated to the ONNO atoms of the ligand in a perfect square planar geometry. The NMR studies of Pd(II) and Ni(II) complexes also supported the highly symmetric nature of the metal complexes. The absorption spectra of the metal complexes showed strong bands in the region of 300–550 nm. The electrochemical studies of metal complexes revealed that only ligand-based oxidation and reduction were observed. The DFT and TD-DFT studies were in agreement with the experimental observations. Our preliminary studies indicated that the Pd(II) complex can be used as a catalyst for the Fujiwara–Moritani olefination reaction. [ABSTRACT FROM AUTHOR]

BNCT is a high-linear-energy transfer therapy that facilitates tumor-directed radiation delivery while largely sparing adjacent normal tissues through the biological targeting of boron compounds to tumor cells. Tumor-specific accumulation of boron with limited accretion in normal cells is the crux of successful BNCT delivery. Given this, developing novel boronated compounds with high selectivity, ease of delivery, and large boron payloads remains an area of active investigation. Furthermore, there is growing interest in exploring the immunogenic potential of BNCT. In this review, we discuss the basic radiobiological and physical aspects of BNCT, traditional and next-generation boron compounds, as well as translational studies exploring the clinical applicability of BNCT. Additionally, we delve into the immunomodulatory potential of BNCT in the era of novel boron agents and examine innovative avenues for exploiting the immunogenicity of BNCT to improve outcomes in difficult-to-treat malignancies. [ABSTRACT FROM AUTHOR]

Identification of trace level chemical species (drugs, pesticides, metal ions and biomarkers) plays key role in environmental monitoring. Recently, fluorescence assay has shown significant advances in detecting of trace level drugs, pesticides, metal ions and biomarkers in real samples. Ultra-small nanostructure materials (metal nanoclusters (NCs), quantum dots (QDs) and carbon dots (CDs)) have been integrated with fluorescence spectrometer for sensitive and selective analysis of trace level target analytes in various samples including environmental and biological samples. This review summarizes the properties of metal NCs and ligand chemistry for the fabrication of metal NCs. We also briefly summarized the synthetic routes for the preparation of QDs and CDs. Advances of ultra-small fluorescent nanosensors (NCs, QDs and CDs) for sensing of metal ions, drugs, pesticides and biomarkers in various sample matrices are briefly discussed. Additionally, we discuss the recent challenges and future perspectives of ultra-small materials as fluorescent sensors for assaying of wide variety of target analytes in real samples. [ABSTRACT FROM AUTHOR]

The neuro-stimulant anti-narcoleptic drug as modafinil (MOD) is used to treatment neurological conditions caused by COVID-19. MOD was used to treatment narcolepsy, shift-work sleep disorder, and obstructive sleep apnea-related sleepiness. So, an innovative, quick, economical, selective, and ecologically friendly procedure was carried out. A highly sensitive N@CQDs technique was created from green Eruca sativa leaves in about 4 min using microwave synthesis at 700 w. The quantum yield of the synthesized N@CQDs was found to be 41.39%. By increasing the concentration of MOD, the quantum dots' fluorescence intensity was gradually quenched. After being excited at 445 nm, the fluorescence reading was recorded at 515 nm. The linear range was found to be in the range 50 – 700 ng mL−1 with lower limit of quantitation (LOQ) equal to 45.00 ng mL−1. The current method was fully validated and bio analytically according to (US-FDA and ICH) guidelines. Full characterization of the N@CQDs has been conducted by high resolution transmission electron microscope (HRTEM), Zeta potential measurement, fluorescence, UV–VIS, and FTIR spectroscopy. Various experimental variables including pH, QDs concentration and the reaction time were optimized. The proposed study is simply implemented for the therapeutic drug monitoring system (TDMS) and various clinical laboratories for further pharmacokinetic research. [ABSTRACT FROM AUTHOR]

New fluorescent nucleobase analogues (FBAs) are emerging as extraordinarily useful tools for DNA labelling technologies. The highly fluorescent adenine analogue 2‐aminopurine (2AP) is still the most used within the few hundreds of newly FBAs synthesized, but its excitation in the UV region demands for high energy sources endangering living cells. New and highly fluorescent 2AP derivatives, 2‐amino‐6‐cyanopurines, were obtained using simpler but efficient synthesis method. All the new compounds exhibit advantageous photophysical properties over 2AP, showing absorption and emission bands ranging the visible region (blue‐green region), high fluorescence quantum yields and Stokes' shifts, especially in non‐protic organic solvents. Density Functional Theory calculations (DFT) of electronic and vibrational structure were performed, allowing to predict absorption and emission spectra. In addition, these 2‐amino‐6‐cyanopurines exhibit little to no toxicity in assays using yeast cells. [ABSTRACT FROM AUTHOR]

Dual‐emissive photoconvertible fluorophores (DPCFs) are powerful tools to unambiguously track labeled cells in bioimaging. We recently introduced a new rational mechanism called directed photooxidation‐induced conversion (DPIC) enabling efficient DPCFs to be obtained by conjugating a coumarin to aromatic singlet‐oxygen reactive moieties (ASORMs). Pyrrole was found to be a suitable ASORM as it provided a high hypsochromic shift along with a fast and efficient conversion. By synthesizing various pyrrole‐based styryl coumarin dyes, we showed that the photoconversion properties, including the quantum yield of photoconversion and the chemical yield of conversion can be tuned by chemical modification of the pyrrole. These modifications led to an improved dual emissive converter, SCP−Boc, which displayed a high brightness and an enhanced photoconversion yield of 63 %. SCP−Boc was successfully used to sequentially photoconvert cells by laser scanning confocal microscopy. [ABSTRACT FROM AUTHOR]

This review presents an analysis of different algorithms for predicting the sensory ability of organic compounds towards metal ions based on their chemical formula. A database of chemosensors containing information on various classes of suitable compounds, including dipyrromethenes, BODIPY, Schiff bases, hydrazones, fluorescein, rhodamine, phenanthroline, coumarin, naphthalimide derivatives, and others (a total of 965 molecules) has been compiled. Additionally, a freely available software has been developed for predicting the sensing ability of chemical compounds, which can be accessed through a Telegram bot. This tool aims to assist researchers in their search for new chemosensors. [ABSTRACT FROM AUTHOR]

9′-cis-norbixin (norbixin/BIO201) protects RPE cells against phototoxicity induced by blue light and N-retinylidene-N-retinylethanolamine (A2E) in vitro and preserves visual functions in animal models of age-related macular degeneration (AMD) in vivo. The purpose of this study was to examine the mode of action and the in vitro and in vivo effects of BIO203, a novel norbixin amide conjugate. Compared to norbixin, BIO203 displays improved stability at all temperatures tested for up to 18 months. In vitro, BIO203 and norbixin share a similar mode of action involving the inhibition of PPARs, NF-κB, and AP-1 transactivations. The two compounds also reduce IL-6, IL-8, and VEGF expression induced by A2E. In vivo, ocular maximal concentration and BIO203 plasma exposure are increased compared to those of norbixin. Moreover, BIO203 administered systemically protects visual functions and retinal structure in albino rats subjected to blue-light illumination and in the retinal degeneration model of Abca4−/− Rdh8−/− double knock-out mice following 6 months of oral complementation. In conclusion, we report here that BIO203 and norbixin share similar modes of action and protective effects in vitro and in vivo. BIO203, with its improved pharmacokinetic and stability properties, could be developed for the treatment of retinal degenerative diseases such as AMD. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) are biocompatible nanoparticles employed in biomedical field, thanks to their size and photophysical properties. GQDs have shown the capability to cross biological barriers, including the blood–brain barrier, which makes them promising agents for brain diseases therapy. It has been shown that surface-functionalized GQDs enhance membrane fluidity and intracellular uptake, exerting a synergistic effect with antitumor drugs at subtherapeutic doses. Here, we tested GQDs effects in combination with chemotherapeutic agents doxorubicin and temozolomide, on a complex 3D spheroid model of glioblastoma. We observed that the capability of GQDs to absorb and convert near-infrared light into heat is a key factor in membrane permeability enhancement on 3D model. This non-invasive therapeutic strategy named photothermal therapy (PTT), combined to chemotherapy at subtherapeutic doses, significantly increased the effect of antitumor drugs by reducing tumor growth and viability. Furthermore, the increase in membrane permeability due to GQDs-mediated PTT enhanced the release of reactive oxygen species with strong migration of the immune system towards irradiated cancer spheroids. Our data indicate that the increase in membrane permeability can enhance the efficacy of antitumor drugs at subtherapeutic doses against glioblastoma, reducing side effects, and directing immune response, ultimately improving quality of life for patients. [ABSTRACT FROM AUTHOR]

meso‐Trimesityl‐substituted [20]smaragdyrin freebase was synthesized by p‐toluenesulfonic acid catalyzed reaction of 5‐mesityldipyrromethane and 2,14‐dibromodipyrrin in an improved yield of 63 %. Unexpectedly, treatment of the [20]smaragdyrin freebase with BF3 ⋅ OEt2 and triethylamine (TEA) gave a stable radical species, in which the BF2 unit is coordinated at the tripyrrin site, probably by ready release of a hydrogen atom of a [22]smaragdyrin BF2 complex. Similar treatment of [22]smaragdyrin free base produced another [22]smaragdyrin BF2 complex, in which the BF2 unit is coordinated at the dipyrrin site. The tripyrrin site coordinated neutral radical was oxidized with AgSbF6 to give a stable antiaromatic cation; this was reduced with NaBH4 to its 22π congener, which was easily oxidized back to the neutral radical in the air and rearranged to thermodynamically stable dipyrrin site coordinated [22]smaragdyrin BF2 complex upon treatment with BF3 ⋅ OEt2 and TEA. Further, the dipyrrin site coordinated [22]smaragdyrin BF2 complex was similarly oxidized to a stable neutral radical and a stable cation in a stepwise manner. This work demonstrates a rare ability of smaragdyrin BF2 complexes to exist in multiple redox states, particularly forming a stable neutral radical by facile release of a hydrogen atom. [ABSTRACT FROM AUTHOR]

Red emissive carbon dots (R-CDs) with an ultra-large Stokes shift of 324 nm were synthesized by the hydrothermal treatment of o-phenylenediamine (OPD) in an HNO3 solution. Multichannels for the detection of pesticides were integrated on a single platform of R-CDs. One channel for detecting fludioxonil with a ratiometric method was designed by producing a fluorescence response to fludioxonil between the excitation and emission peaks with an ultra-large shift. One channel for the detection of imidacloprid with a fluorescent method was built using an inner filter effect (IFE) of imidacloprid on the excitation spectra of R-CDs, far away from its emission band, which can avoid interferences from self-absorption. Another channel for the detection of glyphosate with a fluorimetry and colorimetry dual-mode was constructed using glyphosate with negative charges to neutralize R-CDs with reverse charges, resulting in the aggregation of R-CDs and concentration-dependent fluorescence and absorption responses to glyphosate. [ABSTRACT FROM AUTHOR]

Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) are extensively studied as therapeutic tools. Evaluation of their biodistribution is fundamental to understanding MSC-EVs' impact on target organs. In our work, MSC-EVs were initially labeled with DiR, a fluorescent lipophilic dye, and administered to BALB/c mice (2.00 × 1010 EV/mice) through the following routes: intravenous (IV), intratracheal (IT) and intranasal (IN). DiR-labeled MSC-EVs were monitored immediately after injection, and after 3 and 24 hours (h). Whole-body analysis, 3 h after IV injection, showed an accumulation of MSC-EVs in the mice abdominal region, compared to IT and IN, where EVs mainly localized at the levels of the chest and brain region, respectively. After 24 h, EV-injected mice retained a stronger positivity in the same regions identified after 3 h from injection. The analyses of isolated organs confirmed the accumulation of EVs in the spleen and liver after IV administration. Twenty-four hours after the IT injection of MSC-EVs, a stronger positivity was detected selectively in the isolated lungs, while for IN, the signal was confined to the brain. In conclusion, these results show that local administration of EVs can increase their concentration in selective organs, limiting their systemic biodistribution and possibly the extra-organ effects. Biodistribution studies can help in the selection of the most appropriate way of administration of MSC-EVs for the treatment of different diseases. [ABSTRACT FROM AUTHOR]

Amorphous drug formulations exploiting drug–drug interactions have been extensively studied. This study aims to develop a transdermal system containing an amorphous complex of the nonsteroidal anti-inflammatory drug (NSAID) flurbiprofen (FLU) and lidocaine (LDC) for alleviating chronic pain. The high-viscosity complex between FLU and LDC (Complex) was obtained by heating in ethanol. For the complex, attenuated total reflection-Fourier transform infrared spectroscopy showed a shift in the carboxy-group-derived peak of FLU, and differential scanning calorimetry indicated the endothermic peaks associated with the melting of FLU and LDC disappeared. 13C dipolar decoupling and 15N cross-polarization magic-angle spinning nuclear magnetic resonance measurement suggested the interaction between the carboxyl group of FLU and the secondary amine of LDC. The interaction between the aromatic rings of FLU and LDC contributed to the molecular complex formation. The solubility of FLU from the complex was about 100 times greater than FLU alone. The skin permeation flux of FLU from the complex through the hairless mouse skin was 3.8 times higher than FLU alone in hypromellose gel. Thus, adding LDC to the formulation can be an effective method for enhancing the skin permeation of NSAIDs, which can prove useful for treating chronic pain and inflammatory diseases. [ABSTRACT FROM AUTHOR]

The demand for new fluorophores for different biological target imaging is increasing. Benzo[a]phenoxazine derivatives are fluorochromophores that show promising optical properties for bioimaging, namely fluorescent emission at the NIR of the visible region, where biological samples have minimal fluorescence emission. In this study, six new benzo[a]phenoxazinium chlorides possessing sulfonamide groups at 5-amino-positions were synthesized and their optical and biological properties were tested. Compared with previous probes evaluated using fluorescence microscopy, using different S. cerevisiae strains, these probes, with sulfonamide groups, stained the vacuole membrane and/or the perinuclear membrane of the endoplasmic reticulum with great specificity, with some fluorochromophores capable of even staining the plasma membrane. Thus, the addition of a sulfonamide group to the benzo[a]phenoxazinium core increases their specificity and attributes for the fluorescent labeling of cell applications and fractions, highlighting them as quite valid alternatives to commercially available dyes. [ABSTRACT FROM AUTHOR]

In the present work, Lidocaine: β-Cyclodextrin (LDC:β-CD) complex is formed and confirmed through analytical methods. The absorption and fluorescence maxima of the complex is shifted toward the blue region with the increasing concentration of β-CD. The FT-IR study predicts the entrapment of the aromatic part into the cavity of the host, as the stretching frequencies of those groups are higher than the frequencies of the pure LDC and its physically mixed (PM and KM) products. A best model is arrived through the molecular docking study with the help of Patch-Dock server for the complex formation. The cytotoxic activity of the complex is improved due to the encapsulation process and it is active toward the cancer cells even though, the pure LDC is inert to the cell line in nature. [ABSTRACT FROM AUTHOR]

Tridodecylborate (TD), tritetradecylborate (TT) and trioctadecylborate (TO) were produced as solid-liquid phase change materials (SL-PCMs) for thermal energy storage (TES) applications via condensation of boric acid and 1-dodecanol, 1-tetradecanol, and 1-octadecanol, respectively. Boron is used for the first time in the production of such synthetic PCMs instead of carbonaceous compounds. Produced fatty boron ether compounds were structurally characterized by using FT-IR and proton and carbon NMR spectroscopy methods as they were thermally characterized by DSC and time/temperature analysis techniques. Melting points of TD, TT, and TO are in the range of 10.1–10.8, 26.9–27.0, and 50.8–51.8°C in the thermal cycling tests, respectively, while solid-liquid phase change melting/crystallization enthalpies of them are 110.4/-112.8, 125.7/-132.3, and 141.8/-149.9 Jg-1, respectively. That is, the produced fatty boron-ethers had different operating temperatures than the fatty alcohols from which they were produced and could produce significant enthalpy values for heat energy storage applications. The increase in chain length caused an increase in enthalpy values as in fatty alcohols. The lack of PCM with similar melting and enthalpy values expands the usage area of synthesized boron-ethers. The thermal stability of fatty boron ether compounds (TD, TT, and TO) were tested by 10 times repeated DSC measurements instead of accelerated thermal cycling and FTIR spectroscopy analysis after these operations. In the surface examinations of boron ethers, original crystal formation was observed, and the loss of appearance above the phase transition temperature indicated amorphous transformation. In addition, it has been proven in the TG investigations that the fatty boron ethers produced can remain intact up to higher temperatures than fatty alcohols. [ABSTRACT FROM AUTHOR]