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The study of palladium-catalyzed amination of bromobenzene with aromatic and heterocyclic amines, widely used in the synthesis of organic semiconductors, was performed. The best conditions for the coupling of aryl bromides with carbazole, diphenylamine, phenoxazine, phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, and their derivatives have been developed. Based on the results, nine new star-shaped organic semiconductors, exhibiting up to 100% fluorescent quantum yield in the 400-550 nm range, have been synthesized in good yields. The TDDFT calculations of the absorption spectra revealed a good correlation with experimental results and slight solvatochromic effects with a change in the polarity of the solvent.

Electron donating phenoxazine and phenothiazine groups were introduced in an electron deficient purine structure through a benzene ring bridge to facilitate thermally activated delayed fluorescence. Mitsunobu and Suzuki-Miyaura reactions were used to synthesize the target compounds. Photophysical properties of target compounds were explored and quantum yields in the thin layer film reached up to 8 % and in the PMMA doped thin layer film up to 15 %.

Diketopyrrolopyrrole (DPP) is one of the most used moieties in D–A conjugated polymers for high-performance π-extended conjugated polymer-based organic solar cells. The combination of 1,4-diketo-3,6-dithienylpyrrolo[3,4-c]pyrroles (DTDPPs) and the donor moieties 10-(4-((2-ethylhexyl)oxy)phenyl)-10H-phenothiazine (M1), 10-(4-((2-ethylhexyl)oxy)phenyl)-10H-phenoxazine (M2), has not been reported yet. In this report, novel low-bandgap D–A conjugated polymer derivatives including DTDPP, phenothiazine and phenoxazine were successfully synthesized via direct (hetero) arylation polymerization with in the yields of 40.94–60.77%. The obtained D–A conjugated polymers named poly(3,6-Di(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione)-alt-(10-(4-((2-ethylhexyl)oxy) phenyl)-10H-phenothiazine) (P1) and poly(3,6-Di(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione)-alt-(10-(4-((2-ethylhexyl)oxy) phenyl)-10H-phenoxazine) (P2) exhibited a wide range of absorption spectrum in visible light region and have a low bandgaps of 1.4–1.5 eV, as well as thermal stabilities, these D–A conjugated polymers are very promising as activated polymeric materials for organic solar cells (OSCs).

The prediction and/or rationalization of diarylamine radical-trapping antioxidant (RTA) activity at the elevated temperatures where they are most useful presents a significant challenge, precluding the development of new technology. Whilst structure–activity relationships at ambient temperatures are well established, their predictive capacity at elevated temperatures is poor due to competing reactions. A striking example involves phenoxazine, which is a superior RTA relative to its sulfur analog phenothiazine at ambient temperature (e.g. k = 3.9 × 107vs. 7.6 × 106 M−1 s−1 at 37 °C, respectively), but is demonstrably inferior at elevated temperatures. Despite being inherently less oxidizable in electrochemical experiments and high-accuracy computations, phenoxazine is more rapidly consumed than phenothiazine in autoxidations at 160 °C – a result which we attribute to a lower reorganization energy barrier to oxidation. Given these observations, we surmised that incorporation of an electronegative N-atom into the phenoxazine ring system would decrease the driving force for oxidation and ‘rescue’ its activity. Indeed, this was found to be the case for nitrogen incorporation at any position, regardless of the impact on the inherent RTA activity. Analogous experiments were carried out on phenothiazines into which nitrogen atoms were incorporated, revealing little benefit at 160 °C. These results suggest that for highly reactive diarylamines (i.e. those with k > 106 M−1 s−1), further enhancements in reactivity do not materially improve their ability to inhibit hydrocarbon autoxidation at elevated temperatures. Instead, their stability to one-electron oxidation determines their efficacy., Studies of potent diarylamine antioxidants illustrate how their high-temperature activity can be limited by direct reaction with O2, and how driving force and barrier to oxidation can be modulated for future antioxidant development.

It is a pre-requisite to ionize analyte molecules efficiently for detection by laser desorption/ionization mass spectrometry. Here, we report a conceptual demonstration of cationizing neutral small molecules which are typically difficult to be ionized with the traditional organic matrices due to their low proton/cation affinity values. Our strategy features generating radical cations from site-specifically carboxylated 10-(4-carboxyphenyl)-10H-phenothiazine-3,7-dicarboxylic acid (PTZ(A)2-Ph(A)) with a laser, and anchoring the chlorine ion from NaCl through covalent bond-like bridging interactions with the N/S atoms in the heterocyclic structure. This “Maverick” design allows a dramatic change of the energy landscape of analyte sodiation with an enhanced efficiency. We have synthesized two families of compounds based on the model structures of phenothiazine (PTZ) and phenoxazine (PXZ) and their carboxylated derivatives, and performed comparison between them or against the traditional organic matrices in a systematic format. We have demonstrated that PTZ(A)2-Ph(A) is outstanding as a novel MALDI matrix for the detection of oligosaccharides and amino acids, with an ultra-clean background baseline and high signal-to-noise ratios (up to dozens of times better than the traditional matrices). This work provides a new method for the cationization of neutral small molecules in a distinct mechanism, inspiring the development of next-generation matrices for sensitive detection of hard-to-be-ionized molecules by MALDI MS.

Phenothiazine dyes have attracted significant attention as metal-free sensitizers for dye-sensitized solar cells since their introduction in 2007. Since then, over 430 phenothiazine dyes have been prepared and investigated. Despite the ever-increasing molecular variation, the overall improvement in the power conversion efficiency has been slow. In this review, we identify the traits of successful phenothiazine dyes and shed light on inherent molecular limitations. We include all phenothiazine dyes reported to date, and the big dataset is used to look for trends in photophysical, electrochemical and photovoltaic performance. The dataset used in this study is curated to contain only photovoltaic performance data that is validated using a novel credibility assessment. We compare the distinct sub-geometries of phenothiazine dyes, and investigate the effects of auxiliary donors, the use of π-spacers, DSSC electrolyte compatibility, N-alkyl vs. N-aryl substituents and mono- vs. multianchored vs. tethered dyes. Lastly, the phenothiazine dyes are compared to their closest dye analogue, the phenoxazines. Based on the findings in this review, we believe phenothiazine dyes are unlikely to be the main sensitizers of high-efficiency DSSCs in the future, due to low oxidation potentials, low extinction coefficients and inherent limitations restricting the further optimization of their photophysical properties.

We report here the rational architecture of heteroanthracene-based metal-free organic D−π–A sensitizers (DS-1 and DS-2) and solid organic redox shuttles (ORSs) with common donor moieties phenothiaz...

The host in phosphrescent organic light emitting devices (PhOLEDs), showing the thermally activated delayed fluorescence (TADF) charateristic, can effectively overcome the efficiency roll-off. Herein, six bipolar compounds with donor-π-acceptor (D-π-A) and D-π-A-π-D structures have been synthesized using 1,2,4-triazole derivative (TAZ) as an acceptor and phenothiazine (PTZ), phenoxazine (PXZ), and 9, 9-dimethylacridane (DMAC) as donors. The molecular structures were confirmed by 1H NMR, 13C NMR and X-ray single-crystal diffractions. The large steric hindrance endows these molecules with typical TADF features, including the small singlet-triplet energy splitting ( Δ E S T ) of 0.08–0.30 eV and completely spatially separate highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) electron densities. The PhOLEDs hosted by these novel TADF materials display excellent performances with low efficiency roll-off.

A new series of soluble, solution-processable metallopolyynes of platinum(II) functionalized with electron-rich phenoxazine–oligothiophene rings and their corresponding dinuclear model complexes were synthesized and characterized. The influence of the inclusion of thienyl rings along the polymer chain on the optical, electronic and photovoltaic properties of these metallopolymers was studied. The evolution of the singlet and triplet excited states in these metal-based materials was elucidated in detail. It is shown that addition of the thiophene rings can elevate the HOMO energy level of the polymers. The absorption edge of the oxygen analogue is more red-shifted than that of the sulfur congener, which is attributed to the stronger electron-donating ability of the phenoxazine unit than that of the phenothiazine group. The down-shifted HOMO level of the phenothiazine-based polymer is found to enhance the photovoltaic performance by increasing the open-circuit voltage of the polymer solar cell relative to the phenoxazine-based congener. At the same donor:acceptor blend ratio of 1:4, the light-harvesting capability and solar cell efficiency notably increase as the thienyl rings are added.

Two new coumarin derivatives containing phenothiazine or phenoxazine moiety, 3-(benzo[d]oxazol-2-yl)-7-(10H-phenoxazin-10-yl)coumarin (PXZ-C) and 3-(benzo[d]oxazol-2-yl)-7-(10H-phenothiazin-10-yl)coumarin (PTZ-C), were synthesized and characterized by elemental analysis, NMR spectroscopy, and MS. Their photophysical and electrochemical properties and thermal stabilities were investigated systematically. The results showed that these compounds have good thermal stability. The compound PTZ-C exhibits weak blue–green emission upon ultraviolet light excitation, whereas the compound PXZ-C displays weak blue emission.

Синтезовано ряд нових 3-амінопохідних 3-хлор-10Н-піридо[3,2-b][1,4]бензоксазину та 3-хлор-10H- піридо[3,2-b][1,4]бензотіазину та визначено їх протипухлинну активність. Синтезовані сполуки проаналізовані УФ-, 1H ЯМР-спектроскопією, спектроскопією Фур’є та елемент- ним аналізом. На основі фізико-хімічних властивостей за методом in silico виявлено, що проміжні продукти 3-хлор-10Н- піридо[3,2-b][1,4]бензоксазину і 3-хлор-10H-піридо[3,2-b] [1,4]бензотіазину, та їх карбоксиамідні похідні не порушують правила Ліпінського. За допомогою молекулярного докінгу показано, що синтезовані сполуки непогано взаємодіють з ре- цепторами раку. Визначено, що найвищу протипухлинну активність має 1,3-ді-10H-піридо[3,2-b][1,4]бензотіазин-3-ілсечовина. The synthesis and anticancer activity of a series of new 3-amido derivatives of 3-chloro-10Hpyrido[ 3,2-b][1,4]benzoxazine and 3-chloro-10H-pyrido [3,2-b][1,4]benzothiazine is presented. The synthesized structures were characterized by UV-visible, FT-IR, 1H NMR spectroscopy and elemental analytical data. The in silico physicochemical properties disclosed that neither 3-chloro-10H-pyrido[3,2-b][1,4]benzoxazine and 3-chloro- 10H-pyrido[3,2-b][1,4]benzothiazine intermediates nor their carboxyamido derivatives violate Lipinski’s rule of five. In addition, molecular docking studies showed that they exhibited good interaction with cancer receptors. 1,3-di-10H-Pyrido[3,2-b][1,4]benzothiazin-3-ylurea which showed a significant interaction with all the employed receptors possessed the highest anticancer activity.

Two novel “sister” organic dyes featuring a T-shape molecular pattern based on phenothiazine/phenoxazine and triphenylamine framework as electron donor core and cyanoacrylic acid as acceptor and anchoring group were designed, synthesized and thoroughly characterized. Both dyes were functionalized at the nitrogen atom of phenoxazine/phenothiazine with the triphenylamine unit containing two hexyloxy substituents to obtain a T-shape configuration. The photo-optical and electrochemical data corroborated with time-dependent density functional theory computations and photovoltaic features were discussed in correlation with the structural architecture of each dye. Their performances in dye-sensitized solar cells (DSSCs) were comparatively surveyed with a special concern on the influence of the heteroatom variation on the most important DSSCs characteristics. In spite of its more favorable optical performance, the cells realized with phenoxazine-based dye are less efficient than those fabricated with phenothiazine ones. The cause is the stronger electron interception by the electrolyte in the case of phenoxazine dye which consistently degrades the open-circuit voltage, corroborated with a better regeneration of the phenothiazine by the iodine/iodide redox couple. In fact, to the best of our knowledge, this is one of the first studies which highlights how a single heteroatom in a T-shape dye structure can affect the dye interaction with the electrolyte and its regeneration, consequently the photovoltaic performances and brings out new opportunities for developing novel dyes for efficient DSSCs.

Three novel tripodal bipolar compounds (CNTPA-CZ, CNTPA-PXZ and CNTPA-PTZ) were designed and synthesized, where three functional groups were attached to 1,3,5-positions of the central benzene ring, respectively. In these three compounds, carbazole/phenoxazine/phenothiazine (CZ/PXZ/PTZ) and benzonitrile were applied as electron-donating and electron-withdrawing groups, respectively, to achieve bipolar transport functionality, which was confirmed by the hole-only and electron-only device results. Due to the efficient energy transfer from these compounds to the dopant (Ir(MDQ)2(acac)), the red phosphorescent OLEDs demonstrated high device performance with maximum external quantum efficiency (EQE) over 20%. Particularly, the red OLED hosted by CNTPA-PTZ achieved a maximum efficiency of 42.5 cd/A, 44.3 lm/w and 23.4% with the EQE roll-off ratio of 3.4% from the peak value to that at a brightness of 500 cd/m2.

The photochemical dynamics of three classes of organic photoredox catalysts employed in organocatalyzed atom-transfer radical polymerization (O-ATRP) are studied using time-resolved optical transient absorption and fluorescence spectroscopies. The nine catalysts selected for study are examples of N-aryl and core-substituted dihydrophenazine, phenoxazine and phenothiazine compounds with varying propensities for control of polymerization outcomes. Excited singlet state lifetimes extracted from the spectroscopic measurements are reported in N,N-dimethylformamide (DMF), dichloromethane (DCM) and toluene. Ultrafast (< 200 fs to 3 ps) electronic relaxation of the photocatalysts after photoexcitation at near-UV wavelengths (318-390 nm) populates the first singlet excited state (S1). The S1-state lifetimes range from 130 ps to 40 ns with considerable dependence on the photocatalyst structure and the solvent. Competition between ground-electronic state recovery and intersystem crossing controls triplet state populations and is a minor pathway in the dihydrophenazine derivatives, but is of greater importance for phenoxazine and phenothiazine catalysts. Comparison of our results with previously reported O-ATRP performances of the various photoredox catalysis shows that high triplet-state quantum yields are not a pre-requisite for controlling polymer dispersity. For example, the 5,10-di(4-cyanophenyl)-5,10-dihydrophenazine photocatalyst, shown previously to exert good polymerization control, possesses the shortest S1-state lifetime (135 ps in DMF and 180 ps in N,N-dimethylacetamide) among the nine examples reported here, and a negligible triplet state quantum yield. The results call for a re-evaluation of the excited state properties of most significance in governing the photocatalytic behaviour of organic photoredox catalysts in O-ATRP reactions.

Organic thermally activated delayed fluorescence (TADF) materials are emerging as potential candidates for time-resolved fluorescence imaging in biological systems. However, the development of purely organic TADF materials with bright aggregated-state emissions in the red/near-infrared (NIR) region remains challenging. Here, we report three donor-acceptor-type TADF molecules as promising candidates for time-resolved fluorescence imaging, which are engineered by direct connection of electron-donating moieties (phenoxazine or phenothiazine) and an electron-acceptor 1,8-naphthalimide (NI). Theoretically and experimentally, we elucidate that three TADF materials possessed remarkably small ΔEST to promote the occurrence of reverse intersystem crossing (RISC). Moreover, they all exhibit aggregation-induced red emissions and long delayed fluorescence lifetimes without the influence of molecular oxygen. More importantly, these long-lived and biocompatible TADF materials, especially the phenoxazine-substituted NI fluorophores, show great potential for high-contrast fluorescence lifetime imaging in living cells. This study provides further a molecular design strategy for purely organic TADF materials and expands the versatile biological application of long-lived fluorescence research in time-resolved luminescence imaging.

Aggregation-induced emission (AIE) fluorophores with second near-infrared window (NIR-II) fluorescence are very promising for in vivo imaging because they emit fluorescence in an aggregated state and provide desirable imaging resolution and depth. Up to now, only a limited number of NIR-II AIE fluorophores have been developed. Therefore, synthesizing novel NIR-II AIE fluorophores and investigating structural effects on their photophysical properties are very important for the development of AIE probes. In this work, we synthesized two donor-acceptor-donor-type NIR fluorophores with emissions extending into the NIR-II window named DPTQ-PhPTZ and DPTQ-PhPXZ with phenothiazine (PTZ) and phenoxazine (PXZ) derivatives as the electron donors, respectively, and studied their photophysical properties via theoretical and experimental approaches as well as the properties in NIR-II in vivo imaging. The PTZ and PXZ moieties provided typical AIE characteristics. Despite the very similar chemical structures of PTZ and PXZ, DPTQ-PhPTZ and DPTQ-PhPXZ exhibited rather different photophysical properties, for example, compared to DPTQ-PhPTZ, DPTQ-PhPXZ had higher quantum yield (QY) both in solution and in the aggregated state and its QY was less sensitive to solvent polarity. After being coated with an amphiphilic copolymer F-127, the fluorophores maintained fluorescence, and the formed fluorescent polymer nanoparticles (NPs) had satisfactory tumor accumulation and biocompatibility, implying that they are applicable for in vivo tumor detection.

From their traditional applications as dyes and pigments, phenothiazines and phenoxazines have gained prominent place in medicine as pharmacological lead structures. Recently these compounds and their derivatives have found robust application in organo-electronics and material sciences. This has prompted unprecedented exploratory modification of the parent structures via organic synthesis with a view of synthesizing novel derivatives with improved biological and material properties. This review underscored various synthetic transformative stages of phenothiazine and phenoxazine scaffolds.

Herein, a comparative analysis was carried out to investigate the relationship between performance and structures of PTZ-2 and POZ-2 which based on the units of phenothiazine (PTZ) and phenoxazine (POZ) respectively. The spectral analysis shows that the maximum absorption peaks of these two dyes are 438 nm (PTZ-2) and 465 nm (POZ-2). Electrochemical analysis demonstrate that the better light-harvesting performance of POZ-2 dye is due to its narrow E0–0 (zero–zero transition Energy). Further photovoltaic measurement results show that the η of POZ-2 is 6.4% (Voc=0.727 V, Jsc=12.58 mA cm−2) which is higher than that of PTZ-2 (η=4.9%, Voc=0.722 V; Jsc=9.06 mA cm−2). Finally, the theoretical calculations show that the C S C bond angle (98°) in PTZ-2 is significantly smaller than the C O C bond angle (116°) in POZ-2 which attribute to the larger atom radius of "S" than "O". Therefore, a more obvious folding deformation was created in the structure of PTZ-2. That was the main cause of the difference performance between these two dyes.

This is the first report on the highest efficiency NIR absorbing Aza-Bodipy small molecules. The molecular engineering of newly synthesized NIR absorbing Aza-Bodipy dyes consists of covalently linked phenothiazine (AZA-PTZ-BOD) and phenoxazine (AZA-POZ-BOD) moieties as terminal groups and Aza-Bodipy as a central core moiety. The highest efficiency for OPV devices of 8.23% is achieved for AZA-PTZ-BOD.

A convenient synthesis of new polycyclic mixed phenothiazine-phenoxazine compounds is described. The cross-coupling of 2,4-diaminothiophenol with 2,3-dichloro-1,4-naphthoquin one at room temperature gave reddish brown 10-amino-6-chlorobenzo[a]phenoxazin-5-one which was converted into a benzoxazinophenothiazin-12-amine in 58% yield via reaction with 2-aminothiophenol under anhydrous basic conditions. A three-component one-pot synthesis improved the yield of benzoxazinophenothia-12-amine to 81% a in shorter time compared to two steps reactions. The synthesis of new azomethine derivatives of benzo[a]benzo[5,6] [1,4] oxazino [3,2-c] phenothiazin-12-amine with extended conjugations and excellent yields were also reported. The structural assignments of the prepared compounds were established by combine Ultraviolet-Visible, Fourier Transform Infrared, 1H and 13C Nuclear Magnetic Resonance Spectroscopies, Mass Spectrometry and elemental analytical data. The ease of preparations in high yields and their intense colourations make these compounds applicable as dyestuffs.

Two angular phenothiazines and one angular phenoxazine were successfully synthesized via anhydrous base condensation reaction of 2,6-diamino-4-chloropyrimidine-5-thiol, with 7-chloro-5,8-quinolinequinone,2-aminothiophenol and 2-aminophenol, respectively. Condensation reaction between 2-6-diamino-4-chloropyrimidine-5-thiol and 7-chloro-5,8-quinolinequinone in the presence of anhydrous sodium carbonate yielded 10-amino-8-chloro-1,9,11-triaza-5H-benze[a]phenothiazine-5-one, 1-aza-5H-benzo[a]phenothiazine-5-one and 1-aza-5H-benzo[a]phenoxazine-5-one were produced with anhydrous basic condensation between 7-chloro-5,8-quinolinequinone and 2-aminothiophenol and 2-aminophenol respectively. These angular azaphenothiazin-5-ones and angular azaphenoxazine-5-one were converted to their derivatives via palladium(o)/piperazine ligand utilizing Mizoroki–Heck cross coupling tandem reaction to obtain six derivatized compounds. The synthesized compounds are intensely coloured and their structural elucidation were established by combined spectroscopic and elemental analytical data. In silico and in vitro screening methods were used to investigate the antibacterial potencies of the compounds. All the compounds, except one, interacted with Type I SPase, an unconventional validated antibiotic enzyme targeted in combating antibacterial resistant, at low micromolar range. They also showed activity against the tested bacteria: Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. In fact, B. cereus exhibited more susceptibility towards four of the compounds than the standard drug—ciprofloxacin. The predicted binding modes of four compounds with outstanding activities were finally studied to identify vital ligand–protein interactions, which can serve as template during activity optimization process.

Aiming to develop new deep-red/near-infrared emitters, benzanthrone as a new acceptor moiety with a rigid molecular structure was used. For the design of target compounds phenothiazine and phenoxazine moieties with strong electron-donating ability were also used. Such combination allowed new materials demonstrating thermally activated delayed fluorescence (TADF) in the long wavelength region to be obtained. The maximum intensity of fluorescence of the solid samples of the synthesized compounds was observed at 700 nm. Electroluminescence was peaked at similar wavelength when the compounds were used as emitters for the fabrication of non-doped organic light-emitting diodes. Due to the different substitutions of benzanthrone moieties, the values of TADF lifetimes at room temperature were found to be of in the range of 291–1198 μs which are directory related to their different oxygen sensing properties. Due to high sensitivity to the presence of oxygen in the atmosphere one of the obtained compounds was used for radiometric oxygen sensing. The film of molecular dispersion of phenoxazine containing compound in inert polymer ZEONEX® showed the ratio of intensity of TADF taken in vacuum and of prompt fluorescence taken under oxygen purge of 15.2. The oxygen sensitivity of the film estimated by Stern-Volmer constant was found to be of 1.6 × 10−4 ppm−1 demonstrating good reversibility. The time dependent density functional theory (DFT) calculations were used for the interpretation of the experimental results related to the structure and photophysical properties of the compounds.

A novel electron acceptor based on 10-phenyl-10H-phenothiazine 5,5-dioxide (2PTO) was introduced for the first time to construct aggregation-induced delayed fluorescence materials. The emitter PXZ2PTO contains phenoxazine as the electron donor, exhibiting both AIE characteristics and TADF properties. Due to the highly stereoscopic structure and small ΔEST of PXZ2PTO, a green non-doped TADF OLED realized a high maximum EQE, CE and PE of 16.4%, 44.9 cd A−1 and 32.0 lm W−1, respectively, without using any optical outcoupling technology, which is comparable with the best reported non-doped TADF OLEDs. In addition, the efficiency of the non-doped devices are comparable with that of doped PXZ2PTO devices, with the maximum EQE, CE and PE of 16.3%, 43.8 cd A−1 and 35.2 lm W−1, respectively.

Three star-shaped D-π-A compounds with a 1,3,5-triazine core and N -aryl chromophore (3,6-di- tert -butylcarbazole, phenoxazine and phenothiazine) substituted fluorene arms were designed and synthesized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. All compounds exhibit strong 1 π–π* transitions in the UV region and intense 1 π–π*/intramolecular charge transfer ( 1 ICT) absorption bands in the UV–vis region. Bathochromic shifts of the 1 ICT bands were caused by the electron-donating N -aryl chromophores. All compounds exhibit aggregation induced emission properties in a solvent, and relatively high quantum efficiency in solid-states ( Φ = 10%–20%). Moreover, these compounds show two-photon absorption (TPA) properties due to their good planarity and large π-conjugation. The largest TPA cross section value reaches up to 5000 GM at 800 nm. The multifunctional properties make these compounds potential candidates for application in organic light-emitting materials and two-photon bioimaging.

DG acknowledges to the ERDF PostDoc grant No. 1.1.1.2/VIAA/1/16/177 . This research was funded by the European Regional Development Fund according to the supported activity ‘Research Projects Implemented by World-class Researcher Groups’ under Measure No. 01.2.2-LMT-K-718 ., Towards highly efficient doping-free organic light-emitting diodes, five benzonitrile-based emitters with different substitution pattern were designed exploiting symmetrical donor-acceptor-donor and asymmetrical donor-acceptor-donor* structures. As it was predicted by theoretical calculations, different thermally activated delayed fluorescence of different energy with relatively high absolute quantum yields (11–42%) was detected for non-doped films of the studied compounds. The smallest singlet-triplet energy splitting of 0.05 eV thus the most efficient TADF was estimated for the film of compound with the asymmetrical donor-acceptor-donor* structure containing carbazole and acridan donor moieties. Thermogravimetry revealed sublimation of the materials with the onset temperatures in the range of 350–383 °C. Glass transition temperatures of the molecular materials were in the range of 82–94 °C. Tuning of hole injection properties of these compounds in solid-state was demonstrated. Their ionization potential was in range from 5.8 to 6.0 eV. Strong effect of different substitutions was observed on hole mobilities of the layers of compounds. They were found to be in the wide range from 3 × 10−7 cm2V−1s−1 to 1 × 10−4 cm2V−1s−1. Electron mobility values of the compounds were found to be comparable and ranged from 1.5 × 10−4 cm2V−1s−1 to 3 × 10−4 cm2V−1s−1 at electric field of 6.9 × 105 Vcm−1. Reflecting effect of substitution pattern of benzonitrile on electroluminescent properties of OLEDs, maximum external quantum efficiencies in the range from 1.6 to 5% as well as maximum brightness in the wide range from 1200 to 22600 cd/m2 were observed for the devices based on the doping-free light-emitting layer, European Regional Development Fund 1.1.1.2/VIAA/1/16/177; European Regional Development Fund 01.2.2-LMT-K-718; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART², https://www.sciencedirect.com/science/article/pii/S0143720819312380

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Inspired by the cytotoxicity of perphenazine toward cancer cells and its ability to activate the serine/threonine protein phosphatase 2A (PP2A), we prepared series of ether-carbon linked analogs of a constrained synthetic sphingolipid analog 3, known for its cytotoxicity, nutrient transporter down-regulation and vacuolation properties, incorporating the tricyclic neuroleptics phenoxazine and phenothiazine to represent hybrid structures with possible synergistic cytotoxic activity. While the original activity of the lead compound 3 was diminished by fusion with the phenoxazine or phenothiazine tethered moieties, the corresponding 3-pyridyltetryl ether analog 10 showed cytotoxicity and nutrient transporter down-regulation similar to the lead compound 3, although it separated these PP2A-dependent phenotypes from that of vacuolation.

A series of blue thermally activated delayed fluorescence (TADF) emitters were designed and synthesized using 2,4,6-triphenyl-1,3,5-triazine as the acceptor unit and indenocarbazole derivatives as the electron-donating moiety. In contrast with other six-membered heterocycles, like phenothiazine, phenoxazine, and dihydroacridine, where the TADF efficiency is affected by the presence of different conformers, indenocarbazole derivatives do not show this effect. Therefore, InCz23FlTz, InCz23DPhTz, InCz23DMeTz, and InCz34DPhTz allow the investigation of the effect of different substituents and substitution positions on TADF properties, without the influence of different conformations. We have demonstrated that the substituted position on the carbazole and different substituents in the same position have clear influence on the donor character of indenocarbazole derivatives. Also, the color purity of blue emission and excited states could be adjusted by substituents and substituted position, and thus excellent blue emitters can be obtained. Besides, the four compounds show relatively small TADF contribution under optical excitation; however, excellent performances are obtained in the electroluminescent devices, especially with InCz34DPhTz, which shows a maximum external quantum efficiency of around 26%. In the end, we find an effective way to design high-efficiency blue TADF materials and deeply study the relation between the structure and property in indenocarbazole derivatives.

In variety of skeleton structures of delayed fluorescence molecular materials, the D-A-A type has been widely concerned recently for its improved double efficiency of reverse intersystem crossing process (RISC). Based on the D-A-A structure, eight new D-TRZ-nPO molecules (D = dihydrophenazine (DHPZ), phenothiazine (PTZ), phenoxazine (PXZ) and 9,9-dimethyl-9,10-dihydroacridan (DMAC), TRZ = triphenyltriazine, n = 1 or 2) with potential performance improvement have been deeply investigated by theoretical calculations. Interestingly, these molecules with the closing energy levels of high-lying excited states and charge transfer characters may perform rare high-lying excited state delayed fluorescence. Meanwhile, the changes of RISC and the corresponding effects caused by D-A-A structure from low energy level to high energy level are analyzed in detail. Furthermore, DHPZ-TRZ-2PO with blue emission (452 nm) is expected to be a potential high-lying excited state delayed fluorescence material candidate.

Azaanthracene derivatives, e.g. phenoxazine and phenothiazine, have attracted considerable interest not only in chemistry but also in materials science for the unique electron structures and photophysical properties. However, like most organic luminogens, phenoxazine and phenothiazine both suffer from the annoying aggregation-caused quenching (ACQ) effect, which greatly limits their further application in solid state conditions. Fortunately, the discovery of aggregation-induced emission (AIE) phenomenon provides an elegant platform to solve the stubborn ACQ effect. But most of the existing AIEgens have been prepared through some complicated synthesis processes, which are commonly unpopular with environmental unfriendly, high cost, and low solubility. Therefore, it deserves great attention to explore a simple and cost effective approach to achieve the AIE modification of phenoxazine and phenothiazine. In this work, two diphenylethylene substituted azaanthracene derivatives DPE-POZ and DPE-PTZ were masterly designed and synthesized through a fairly simple one-step reaction. The introduction of multi-rotor group diphenylethylene endows the products with twisted molecular conformations, which successfully promotes the photophysical behavior conversion of ACQ-AIE. The αAIE (the ratio of PL intensity in a mixed solvent with 90 vol% fraction of water to 0 vol%)of DPE-POZ and DPE-PTZ reached 8 and 23, respectively. In addition, DPE-POZ exhibited an uncommon blue-shifted mechanofluorochromic phenomenon. The powder X-ray diffraction and single crystal X-ray diffraction characterizations revealed that the MFC properties could be attributed to the phase transition between the crystalline and amorphous states which was promoted by the loose solid molecular arrangement.

We report here a series of 27 10-(4-phenylpiperazin-1-yl)methanones derived from tricyclic heterocycles which were screened for effects on tumor cell growth, inhibition of tubulin polymerization, and induction of cell cycle arrest. Several analogues, among them the 10-(4-(3-methoxyphenyl)piperazine-1-carbonyl)-10H-phenoxazine-3-carbonitrile (16o), showed excellent antiproliferative properties, with low nanomolar GI50 values (16o, mean GI50 of 3.3 nM) against a large number (93) of cancer cell lines. Fifteen compounds potently inhibited tubulin polymerization. Analysis of cell cycle by flow cytometry revealed that inhibition of tumor cell growth was related to an induction of G2/M phase cell cycle blockade. Western blotting and molecular docking studies suggested that these compounds bind efficiently to β-tubulin at the colchicine binding site. Our studies demonstrate the suitability of the phenoxazine and phenothiazine core and also of the phenylpiperazine moiety for the development of novel and potent tu...

Efficient electron donors, phenothiazine (PTZ)/phenoxazine (POZ) substituted imidazolium (IMI) and benzimidazolium (BIMI) iodide solid organic ionic conductors (SOICs) possessing good thermal stability and high conductivity are synthesized. The high conductivity arises due to the presence of the effective electron donor moiety PTZ/POZ and hence, these SOICs were used as single component solid electrolytes in solid state dye sensitized solar cells (ss-DSSCs). The ss-DSSC devices operate proficiently without any post-treatment to dye loaded TiO2 and additives in the electrolyte matrix. The presence of unsaturation and hetero-atoms in PTZ/POZ is responsible for the hole mobility and enhancement in light harvesting properties. Hence, when SOICs were excited along with a metal-free sensitizer, SK 1,the higher LUMO levels of SOICs increased the total electron injection in the TiO2 interface with the electrons of SK 1. Under illumination of solar light (100 mW cm−2 with an AM1.5G filter), ss-DSSCs with POZ substituted IMI and BIMI as single component solid electrolytes showed power conversion efficiency (PCE) of about 5.7%, which is quite comparable with the conventional imidazolium/benzimidazolium salt based liquid electrolytes and SK 1 sensitizer. The ss-DSSC devices with all four SOICs exhibit good long-term stability (∼1000 h) under 1 sun illumination and ambient humidity conditions. The present report paves the way for the development of single component solid organic ionic conductors having high electronic conductivity and better light harvesting ability as well as thermal stability.

Four novel compounds (1–4) were synthesized using 2-phenyl-4H-1-benzopyran-4-one (flavone) moiety as an acceptor and phenoxazine, phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, diphenylamine as donors. Their photophysical properties were studied with spectroscopic and theoretical methods. The results show that 1 and 2 exhibit good aggregation-induced emission (AIE) properties in tetrahydrofuran (THF)/water mixtures, whose maximum photoluminescence (PL) intensities are 156- and 187-fold higher than those in pure THF solutions, and can reach 256- and 506-fold higher than those in the mixtures at water fractions of 50%, respectively. 3 displays similar PL property except for obvious emission in pure THF solution. However, PL intensity of 4 decreases with an increase in water fraction, and then is enhanced with further increase in water fraction. Moreover, 4 shows high quantum yields both in toluene solution (0.61) and in solid state (0.83). It exhibits a positive solvatochromism. In addition, 2 possesses mechanofluorochromic transition from sky blue to yellow after grinding. It can also be applied in live-cell imaging.

A serial of phenoxazine and phenothiazine based organic chromophores were synthesized with facile routes. Then these chromophores were applied in organic nonlinear optical materials to study the effect of different conjugated direction, extra phenyl ring and alkyl chain on the decomposition temperature, energy level, photophysical properties through Uv–vis spectral, density functional theory calculations. The electro-optic coefficient of poled films containing these chromophores doped in amorphous polycarbonate afforded the largest values of 19 pm/V, 49 pm/V and 23 pm/V at 1310 nm for chromophores B, L1 and L2 respectively. To our regret, chromophore A is not stable enough for test. The geometries of the chromophores were optimized to gain insight into the molecular structure and electron distribution. These results showed that when the phenyl ring was added in chromophore A, B, nearly 90°of the dihedral angle between PTZ and phenyl ring unit leads to the intramolecular charge transfer transition (HOMO-LUMO) being prohibited and showed a smaller hyperpolarizability (β) value.

The synthesis of some new thiophenyl-derivatized and furanyl-derivatized phenothiazine and phenoxazine dyestuffs is described. This was achieved by two methods after the synthesis of 6-chloro-5H-benzo[a]phenothiazin-5-one, 6-chloro-5H-benzo[a]phenoxazin-5-one, and 6-chloro-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one intermediates via anhydrous base condensation reaction of 2,3-dichloro-1,4-naphthoquinone with 2-aminothiophenol, 2-aminophenol, and 2-aminopyridinol, respectively. The first method involved treatment of tributyl(thien-2-yl) or tributyl(furan-2-yl) stannane with chlorophenothiazine/chlorophenoxazine under mild basic chemical formula (CsF) and 1,4-dioxane or toluene solvent at 80°C to supply dazzling yellow solid in high yields. In the second method, the catalytic system was pre-activated in acetonitrile, followed by addition of coupling partners and K3PO4 to obtain high melting and variety of highly colored products in moderate to high yields. The reaction conditions were compatible with unprotected N–H and carbonyl functional groups. The intense colors of these dyes and their ease of re-oxidation of Na2S2O4-reduced derivatives make them suitable as vat dyes. Also, they were found to be good colorants for textiles, papers, paint, ink, soap, polish, candle, and plastic materials.

Chloro-substituted phenothiazines and phenoxazines were successfully derivatized with phenylboronic and styrylboronic acids using Suzuki–Miyaura cross-coupling reaction catalyzed by Pd(0)/XPhos for the first time in good yields. The protocol employed 4 mol% Pd and 7 mol% XPhos with K3PO4 in acetonitrile at 80°C. The reaction condition is compatible with carbonyl and unprotected N–H groups in substrates. Structural assignments were established by combined spectroscopic (UV, IR, 1H, and 13C NMR), MS, and elemental analytical data.

Two novel chromophores based on the phenoxazine (chromophore L1) or phenothiazine (chromophore L2) donor, and tricyanofuran acceptors linked together via thiophene as the bridges have been synthesized and systematically investigated. Cyclic voltammetry measurements showed that chromophore L1 had smaller energy gap than chromophore L2 due to the stronger electron-donating ability. Moreover, Density functional theory calculations suggested that the β value of chromophore L1 is 17% larger than that of chromophore L2. The doped film containing the chromophore L1 showed an r33 value of 49 pm/V at the concentration of 25 wt% which is two times higher than the EO activity of the chromophore L2 (23 pm/V) and the traditional aryl chromophore (10–20 pm/V). High r33 value, high thermal stability (onset decomposition temperatures higher than 220 °C) suggests the potential use of the new chromophore in nonlinear optical materials.

An efficient and versatile Pd-catalyzed tandem C–N bond formation between aryl halides and primary amines is developed. The transformation allows a one-pot synthesis of phenoxazine and phenothiazine derivatives with a broad range of substitution patterns from readily available precursors.

Quinonoid compounds widespread in wildlife are involved in many biological processes and are extremely important for almost every living organism. On the other hand, the features of the structure of quinones cause a wide range of their chemical transformations. They are active in many homolytic and heterolytic reactions capable of cycloaddition. A practically important group of reactions leading to the formation of heterocyclic compounds with nitrogen atoms in the cycle is the interaction between benzo- and naphthoquinones and aliphatic and aromatic diamines as well as their derivatives. However, among the condensed nitrogen-containing heterocycles there were found practically useful substances for which anticancer, antiparasitic, antimicrobial and other biological activities were recorded. For example, the main representatives of the group of arylamine dyes are derivatives of phenazine, phenothiazine and phenoxazine. Phenazines are also widely used in the field of organic electronics, in particular, they are integrated into solar cells and OLED devices. Possibility of preparation of angular heterocyclic systems based on 3-aryl-1,2-naphtho-quinones were investigated. The 3-aryl-1,2-naphthoquinones 1–6 (аryl = 4-ClC 6 H 4 (1), 4-BrC 6 H 4 (2), 3-NO 2 C 6 H 4 (3), 4-NO 2 C 6 H 4 (4), 2,5-Cl 2 C 6 H 3 (5), 3,4-Cl 2 C 6 H 3 (6)) were obtained by means of the reaction between arenediazonium salts and 1,2-naphthoquinone under Meerwein reactions conditions. The reactions were carried out in formic acid – water medium in the presence of sodium acetate and catalytic amounts of copper salts. The yields of arylnaphthoquinones 1–6 are in range of 20–50 %. The reaction of 3-aryl-1,2-naphthoquinones 1–6 with benzene-1,2-diamine led to the formation of fused angular heterocyclic systems of 6-arylbenzo[ a ]phenazines 7–12 in high yields. The structures of the synthesized compounds were verified by the 1 H NMR spectroscopy and element analysis data. Key words: 1,2-naphthoquinone, benzene-1,2-diamine, 3-aryl-1,2-naphthoquinones, Meerwein arylation reaction, benzo[ a ]phenazines.

We report the synthesis of conjugated oligomers based on electron withdrawing 3,4-ethylenedioxythiophene (EDOT) in the case of which band gaps are tuned by the insertion of alkylated diphenylamine or phenoxazine/phenothiazine units. The structures and properties of synthesized compounds were characterized by 1 H NMR, 13 C NMR, UV-Vis absorption, and fluorescence spectroscopy as well as electrochemical measurements. The luminescence spectra demonstrate that copolymers are good chromophores. Also the electrical properties confirm the applicability of these novel aryl-based π-conjugated oligomers for the development of various electrical and electrochemical devices.

Four new organic dyes, coded as CSORG6 , CSORG7 , CSORG8 and CSORG9 , comprising electron rich thiophene derivatives as antennas and cyanoacrylic acid as acceptor, bridged by phenothiazine or phenoxazine were designed and synthesized for dye-sensitized solar cells applications. They were fully characterized with their photophysical, electrochemical properties, density functional theory (DFT), time dependent density DFT (TDDFT) and the light-harvesting properties of the new sensitizers were evaluated with nanocrystalline TiO 2 -based devices. Among the four diheteroanthracene based dyes, phenoxazine ( CSORG7 and CSORG9 ) based devices afforded the best photovoltaic performance ( η ) of 6% under standard AM 1.5G solar irradiation, whereas, N719 showed ( η ) 6.4% under the similar fabrication and evolution conditions.

Multi-branched multi-anchoring metal-free dyes as photosensitizers for dye-sensitized solar cells (DSSCs) are reviewed. The article outlines design strategies, main synthetic routes and optical and photovoltaic properties of two families of multi-branched sensitizers: (a) D–(π–A)n (D = donor, π = π-spacer, A = acceptor/anchoring functionality) structures containing arylamine, carbazole, phenothiazine or phenoxazine derivatives as D groups, and (b) multi-donor multi-anchoring architectures from interconnected mono-branched D–π–A arms, together with X- and Y-shaped dyes. Although this class has been reported only in the last five years, a variety of molecular architectures, donors, and π-spacers have been used and combined in multi-branched molecules. The multi-branched geometry induces distinctive features including enhanced qualitative and quantitative optical properties, increased currents and quantum efficiencies, and control of molecular aggregation.

Donor-acceptor type 1,3-indandione derivatives were synthesized and their thermal, optical, photophysical, electrochemical, and photoelectrical properties were studied. They form glasses with the glass transition temperatures ranging from 164 to 249°C. 3,6-di(1,3-indandionyl)-10-methyl-phenothiazine showed the lowest energy emission bands in all the investigated solvents, as well as the largest Stokes shifts. Cyclic voltammograms of the synthesized compounds showed one reversible oxidation couple and quasi-reversible reduction waves. The ionization potentials of the solid samples of the synthesized materials were found to be in the range of 5.52–6.01 eV.

Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the black dye (N749), have been evaluated as sensitizers for dye sensitized solar cells (DSSCs). The modification is carried out by attaching selected chromophores, with varying electron donating strength, covalently to the central ring of the ligand. The complexes, compared to the parent dye, show red shifted absorption covering visible and near IR regions and higher molar extinction coefficients. We report in this work synthesis of a series of these ruthenium complexes with chromophores such as tert-butyl phenyl, triphenylamine, bithiophene, phenoxazine and phenothiazine. Detailed experimental characterization using optical, electrochemical and photovoltaic techniques has been carried out and complemented by density functional theory studies. The fill factors (ff) obtained for these dyes are larger than those of the parent black dye. In spite of these superior properties, the dyes show only moderate to good power conversion efficiencies. The possible reasons for this have been investigated and discussed.

A series of organic dyes (POZ-2, POZ-3, POZ-4 and POZ-5) involving phenoxazine were synthesized as sensitizers for application in dye-sensitized solar cells (DSSCs). For comparison, three different electron donors namely 10-phenyl-10H-phe-nothiazine, 10-phenyl-10H-phenoxazine and triphenylamine were separately appended onto the 7-position of the model dye (POZ-2). The obtained four dyes exhibit considerably high values of conversion efficiencies of 6.6%, 7.8%, 7.1% and 6.4%, respectively, under the simulated AM1.5G conditions. The geometries of the dyes were optimized to gain insight into the molecular structure and electron distribution, and then the charge extraction and transient photovoltage decay measurements were further performed to understand the influence of electron donors on the photovoltaic behaviors.

In this study, the binding points of MethB and two structurally-related cationic phenoxazine dyes [meldola blue (MB) and nile blue (NB)] to human butyrylcholinesterase (BChE) were investigated by molecular docking and site directed mutagenesis. The comparative inhibitory effects of MethB, MB and NB on recombinant wild type BChE and six human BChE mutants were spectrophotometrically studied. Kinetic analyses yielded the following information: MethB and MB were found to cause nonlinear inhibition of all recombinant BChEs except Y332A, compatible with a multi-site binding model. On the other hand, MethB and MB caused linear mixed inhibition of Y332A mutant, compatible with a single binding mode. Comparing the inhibitory effects in aspect of K-i values with recombinant wild type BChE (K-i = 0.042 mu M), MethB was found to be similar to 30, 80 and 270-fold less effective as an inhibitor of Y332A, F329A and T120F, respectively. NB caused nonlinear inhibition of all recombinant BChEs. The inhibitory effect of NB on Y332A mutant was similar to 370-fold lower, compared to recombinant wild type BChE (K-i = 0.006 mu M). Considering both kinetic and molecular docking results together, it was concluded that threonine 120, phenylalanine 329 and tyrosine 332 are critical amino acids in binding of cationic phenoxazine/phenothiazine structured ligands to human BChE. (C) 2013 Elsevier Inc. All rights reserved.

The phenothiazine group has been identified as a suitable A ring in the structure of tubulin polymerization inhibitors. In our search to identify more potent inhibitors, a study of different isosteric tricyclic groups as new potential A rings was first realized and permitted to identify 1-azaphenothiazine and iminodibenzyl as favorable modulations providing compounds with improved activity against tubulin. An investigation of the methylene group as the connector between the A and B rings revealed that the "CH2" bridge was tolerated, improving the biological potency when the A unit was of phenothiazine, 1-azaphenothiazine or iminodibenzyl type. Molecules 6-8 and 12 showed increased biological activity in comparison to parent phenstatin 2 on COLO 205 colon cancer cell line. The most antineoplastic agent in the current study was phenothiazine 5 displaying a GI50 of 25nM against the melanoma MDA-MB-435 cell line.