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Organic dyes hold promise as inexpensive electrochemically‐active building blocks for new renewable energy technologies such as redox‐flow batteries and dye‐sensitised solar cells, especially if they display high oxidation and/or low reduction potentials in cheap, non‐flammable solvents such as water or protic ionic liquids. Systematic computational and experimental characterisation of a representative selection of acidic and basic dyes in buffered aqueous solutions and propylammonium formate confirm that quinoid‐type mechanisms impart electrochemical reversibility for the majority of systems investigated, including quinones, fused tricyclic heteroaromatics, indigo carmine and some aromatic nitrogenous species. Conversely, systems that generate longlived radical intermediates – arylmethanes, hydroquinones at high pH, azocyclic systems – tend to display irreversible electrochemistry, likely undergoing ring‐opening, dimerisation and/or disproportionation reactions. [ABSTRACT FROM AUTHOR]

Although second near‐infrared (NIR‐II, 1000–1500 nm) light has attracted considerable attention, especially for life sciences applications, the development of organic dyes with NIR‐II absorption remains a formidable challenge. Herein we report the design, synthesis, and electronic properties of 20π‐electron antiaromatic benziphthalocyanines (BPcs) that exhibit intense absorption bands in the NIR region. The strong, low‐energy absorption of the antiaromatic BPcs is attributed to electric‐dipole‐allowed HOMO‐LUMO transitions with narrow band gaps, enabled by the reduced structural symmetry of BPc compared with regular porphyrins and phthalocyanines. The combination of peripheral substituents and a central metal decreases the HOMO‐LUMO energy gaps, leading to the extension of the absorption bands into the NIR‐II region (reaching 1100 nm) under reductive conditions. [ABSTRACT FROM AUTHOR]

Inorganic‐organic hybrid materials are a kind of multiduty materials with high crystallinity and definite structures, built from functional inorganic and organic components with highly tunable photochemical properties. Perylenediimides (PDIs) are a kind of strong visible light‐absorbing organic dyes with π‐electron‐deficient planes and photochemical properties depending on their micro‐environment, which provides a platform for designing tunable and efficient hybrid photocatalytic materials. Herein, four radical‐doped PDI‐based crystalline hybrid materials, Cl4‐PDI⋅SiW12O40 (1), Cl4‐PDI⋅SiMo12O40 (2), Cl4‐PDI⋅PW12O40 (3), and Cl4‐PDI⋅PMo12O40 (4), were attained by slow diffusion of polyoxometalates (POMs) into acidified Cl4‐PDI solutions. The obtained PDI‐based crystalline hybrid materials not only exhibited prominent photochromism, but also possessed reactive organic radicals under ambient conditions. Furthermore, all hybrid materials could be easily photoreduced to their radical anions (Cl4‐PDI⋅−), and then underwent a second photoexcitation to form energetic excited state radical anions (Cl4‐PDI⋅−*). However, experiments and theoretical calculations demonstrated that the formed energetic Cl4‐PDI⋅−* showed unusual POM‐dependent photocatalytic efficiencies toward the oxidative coupling of amines and the iodoperfluoroalkylation of alkenes; higher photocatalytic efficiencies were found for hybrid materials 1 (anion: SiW12O404−) and 2 (anion: SiMo12O404−) compared to 3 (anion: PW12O403−) and 4 (anion: PMo12O403−). The photocatalytic efficiencies of these hybrid materials are mainly controlled by the energy differences between the SOMO‐2 level of Cl4‐PDI⋅−* and the LUMO level of the POMs. The structure‐photocatalytic activity relationships established in present work provide new research directions to both the photocatalysis and hybrid material fields, and will promote the integration of these areas to explore new materials with interesting properties. [ABSTRACT FROM AUTHOR]

Tuning the topology of two‐dimensional (2D) covalent organic frameworks (COFs) is of paramount scientific interest but remains largely unexplored. Herein, we present a site‐selective synthetic strategy that enables the tuning of 2D COF topology by simply adjusting the molar ratio of an amine‐functionalized dihydrazide monomer (NH2−Ah) and 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzaldehyde (Tz). This approach resulted in the formation of two distinct COFs: a clover‐like 2D COF with free amine groups (NH2−Ah−Tz) and a honeycomb‐like COF without amine groups (Ah−Tz). Both COFs exhibited good crystallinity and moderate porosity. Remarkably, the clover‐shaped NH2−Ah−Tz COF, with abundant free amine groups, displayed significantly enhanced adsorption capacities toward crystal violet (CV, 261 mg/g) and congo red (CR, 1560 mg/g) compared to the non‐functionalized honeycomb‐like Ah−Tz COF (123 mg/g for CV and 1340 mg/g for CR), underscoring the pivotal role of free amine functional groups in enhancing adsorption capacities for organic dyes. This work highlights that the site‐selective synthetic strategy paves a new avenue for manipulating 2D COF topology by adjusting the monomer feeding ratio, thereby modulating their adsorption performances toward organic dyes. [ABSTRACT FROM AUTHOR]

Aerogels present a huge potential for removing organic dyes from printing and dyeing wastewater (PDW). However, the preparation of aerogels with multiple dye adsorption capabilities remains a challenge, as many existing aerogels are limited to adsorbing only a single type of dye. Herein, a composite aerogel (CG/T‐rGO) with the addition of carboxymethyl chitosan, gelatin and tannic acid reduced graphene oxide (T‐rGO) was synthesized by freeze‐drying technology. The electrostatic interactions between dye molecular and GEL/CMCS (CG) networks, as well as the supramolecular interactions (H‐bonds, electrostatic interactions and π–π stacks) between T‐rGO, have endowed the aerogel with the ability to adsorb multiple types of dye, such as methylene blue (MB) and methyl orange (MO). Results exhibited that the prepared CG/T‐rGO aerogel possessed strong mechanical strength and a porous 3D network structure with a porosity of 96.33 %. Using MB and MO as adsorbates, the adsorption capacity (88.2 mg/g and 66.6 mg/g, respectively) and the mechanism of the CG/T‐rGO aerogel were investigated. The adsorption processes of aerogel for MB and MO were shown to follow the pseudo‐second‐order kinetic model and Langmuir isotherm model, indicating the chemical adsorption of a monolayer. The proposed aerogel in this work has promising prospects for dye removal from PDW. [ABSTRACT FROM AUTHOR]

Light‐gated chemical reactions allow spatial and temporal control of chemical processes. Here, we suggest a new system for controlling pH‐sensitive processes with light using two photobases of Arrhenius and Brønsted types. Only after light excitation do Arrhenius photobases undergo hydroxide ion dissociation, while Brønsted photobases capture a proton. However, none can be used alone to reversibly control pH due to the limitations arising from excessively fast or overly slow photoreaction timescales. We show here that combining the two types of photobases allows light‐triggered and reversible pH control. We show an application of this method in directing the pH‐dependent reaction pathways of the organic dye Alizarin Red S simply by switching between different wavelengths of light, i. e., irradiating each photobase separately. The concept of a light‐controlled system shown here of a sophisticated interplay between two photobases can be integrated into various smart functional and dynamic systems. [ABSTRACT FROM AUTHOR]

The development of efficient photocathodes is of critical importance for the constructions of promising tandem photo‐electrochemical cells. Most known dye‐sensitized photocathodes are prepared with the conventional carboxylic or phosphonic acid anchors and require the presence of other terminal linking groups to connect catalysts; they suffer from high synthetic difficulty and low adsorption stability in aqueous media. Here, a compact bilayer photocathode has been prepared by using a pyrene‐based photosensitizer with multiple terminal pyridine moieties as both the anchoring and linking groups to connect a Co hydrogen‐evolution catalyst to the NiO substrate. The catalyst and dye molecule are assembled in a layer‐by‐layer manner on NiO through the metal‐pyridine coordination. This photocathode exhibits good dye adsorption stability in aqueous media. A stable cathodic photocurrent of 70 μA cm−2 was achieved, with H2 being generated at the photocathode under the visible‐light irradiation. The Faraday efficiency of H2 evolution was estimated to be 9.1 %. Transient absorption spectral studies suggest that the interfacial hole transfer occurs within a few picoseconds. The integration of the organic photosensitizer with pyridine anchoring and linking groups is expected to provide a simple method for the fabrication of stable and efficient photocathodes. [ABSTRACT FROM AUTHOR]

Owing to its hydrophobic properties and reactivity, triarylphosphines (PAr3) are promising precursors for the development of new amphiphiles. However, an efficient and reliable synthetic method for amphiphiles based on highly hydrophobic PAr3 is still required. Herein, a straightforward transformation of highly hydrophobic PAr3 into amphiphiles via the Staudinger reaction is reported. By simply mixing PAr3 and a hydrophilic trichlorophenyl azide containing two hydrophilic chains, amphiphiles bearing a N=P bond (i. e. an azaylide moiety) were quantitatively formed. The obtained azaylide‐based amphiphiles were remarkably water‐soluble, enabling their spontaneous self‐assembly into 2 nm‐sized micelles composed of 4–5 molecules in water with a low critical micelle concentration (up to 0.05 mM or less) due to the effective intermolecular interactions among the hydrophobic surfaces. Although the azaylide moiety is easily hydrolyzed in the presence of water, the azaylide in the amphiphiles displayed notable stability in water even at 60 h, which stems from the LUMO modulation induced by the presence of three electron‐withdrawing chloro groups and two twisted alkoxycarbonyl groups, according to DFT calculations. An amphiphile having a large hydrophobic surface solubilized various hydrophobic organic dyes through efficient intermolecular interactions, resulting in the dyes exhibiting either monomer or excimer emissions in water. [ABSTRACT FROM AUTHOR]

Dye‐dye conjugates have attracted significant interest for their utility in applications such as bioimaging, theranostics, and light‐harvesting. Many classes of organic dyes have been employed in this regard; however, building blocks don't typically extend beyond small chromophores. This can lead to minor changes to the optoelectronic properties of the original dye. The exploration of dye–dye structures is impeded by long synthetic routes, incompatible synthetic conditions, or a mismatch of the desired properties. Here, we present the first‐of‐their‐kind dye‐dye conjugates of boron difluoride complexes of formazanate and dipyrromethene ligands. These conjugates exhibit dual photoluminescence bands that reach the near‐infrared spectral region and implicate anti‐Kasha processes. Cyclic voltammetry experiments revealed the generation of polyanionic species that can reversibly tolerate the uptake of up to 6 electrons. Ultimately, we demonstrate that BF2 formazanates can serve as a synthetically accessible platform to build upon new classes of dye‐dye conjugates. [ABSTRACT FROM AUTHOR]

The macrocyclic proligand [H4L][OTf]2, which contains four carboxamide functions and two conjugated pyridinium groups, is easily deprotonated by the weak base sodium acetate to give the corresponding neutral proligand [H2L]. Metallation of [H2L] with iron(II) chloride proceeds rapidly to form the macrocyclic complex, [FeIIICl(L)]. This is an effective catalyst for the oxidation of the organic dye orange II by hydrogen peroxide in aqueous solution, and the kinetic parameters for this reaction have been determined. In striking contrast to an analogous iron‐TAML complex that contains two phenyl groups in place of the two pyridinium groups, [FeIIICl(L)] is a very active oxidation catalyst at pH 7 and is also highly stable towards acid‐promoted demetallation at pH 5 or above. The results show that the two pyridinium groups bring greatly enhanced catalytic properties to [FeIIICl(L)]. [ABSTRACT FROM AUTHOR]

Instrumental techniques able to identify and structurally characterize the aggregation states in thin films of chiral organic π‐conjugated materials, from the first‐order supramolecular arrangement up to the microscopic and mesoscopic scale, are very helpful for clarifying structure‐property relationships. Chiroptical imaging is currently gaining a central role, for its ability of mapping local supramolecular structures in thin films. The present review gives an overview of electronic circular dichroism imaging (ECDi), circularly polarized luminescence imaging (CPLi), and vibrational circular dichroism imaging (VCDi), with a focus on their applications on thin films of chiral organic dyes as case studies. [ABSTRACT FROM AUTHOR]

Some organic dyes and photosensitizers with strong visible absorption can behave as photo‐responsive oxidase mimics. However, the relationship between the photo‐oxidase activity and molecular structure remains unclear to date. In this work, a new type of photosensitizer with the characteristics of molecular rotors, namely DPPy, served as the molecular scaffold for further investigation. To adjust the photocatalytic oxidation ability, DAPy and CBPy were designed and synthesized based on the enhancement and diminishment of the intramolecular charge transfer (ICT) process, respectively. Kinetic studies revealed that DAPy and CBPy both exhibited highly efficient photo‐activated oxidase‐like activity with 3,3′,5,5′‐tetramethylbenzidine (TMB) as the substrate, which were in good accordance with their molecular engineering to promote either type I or type II reactive oxygen species (ROS) generation. Impressively a colorimetric method based on the visible light induced oxidase‐like activity of molecular rotors was developed to determine the environmental temperature for the first time. Both DAPy and CBPy showed distinct sensitivities toward temperature as compared with several molecular rotors based on the typical fluorimetric detection. This work provides a new strategy for the application of molecular rotors to overcome the non‐emissive challenge in temperature sensing. [ABSTRACT FROM AUTHOR]

1,8‐Naphthalimides (NIs) represent a class of organic dyes with interesting optical properties that has been extensively explored in the last decades in lighting devices, chemosensors, optical probes or medicinal chemistry. However, despite their remarkable potential, reports on organometallic dyes bearing NIs are scarce and virtually inexistent regarding palladium(II) complexes. Herein, we report the synthesis of NIs bearing phosphine and amine chelating moieties and the characterization of their optical properties both as single molecules and when complexed on Pd(II) ions. It is shown that the introduction of phosphine moieties in the naphthalimide core results in a marked increase in non‐radiative processes, leading to a significant reduction of the emission efficiency and lifetime of these dyes, compared to amine‐bearing counterparts. The complexation to Pd(II) sequesters the electronic contribution of chelating moieties, with complexes assuming an optical behavior similar to that of unsubstituted 1,8‐naphthalimide. The complexation significantly increases the acidity of chelating secondary amines, giving rise to an unexpected intramolecular reaction that results in the formation of a novel 1,8‐naphthalimide dye bearing a cyclic phosphorylamide moiety. The new dye exhibits good emission quantum yield, long fluorescence lifetime and sensitivity to basic media, evidencing potential for application in optical imaging and sensing scenarios. [ABSTRACT FROM AUTHOR]

In the past decades, great efforts have been made to develop novel visible‐light photocatalysts to achieve high photocatalytic efficiency by utilizing visible light, the largest proportion of solar energy. As a new type of photocatalyst materials, all‐inorganic lead‐free halide double perovskites have begun to attract widespread interest. Herein, double perovskite Cs2AgBiCl6 was developed into a visible‐light photocatalyst for degrading organic dyes. Cs2AgBiCl6 was prepared by the hydrochloric acid precipitation and anti‐solvent recrystallization methods, respectively, and was used to degrade organic dyes under visible light. Samples prepared by the anti‐solvent recrystallization method are smaller than those prepared by the hydrochloric acid precipitation method, which can degrade 95.7 % of Sudan III in 10 min and show excellent photocatalytic activity. The cyclic experiments demonstrate that Cs2AgBiCl6 has a good cycle stability. Moreover, Cs2AgBiCl6‐AS also exhibits good photocatalytic degradation ability for Methyl red and Malachite green. These distinctive results indicate that Cs2AgBiCl6 may be a promising material for developing novel, high‐efficient and stable visible‐light photocatalysts. [ABSTRACT FROM AUTHOR]

We have studied the impact of achiral substituents on the chiral supramolecular architectures of diketopyrrolo[3,4‐c]pyrrole‐1,2,3‐1H‐triazole (DPP) dyes. We decorated the same chiral DPP motif with substituent groups on the nitrogen atoms of the lactam moiety: the hydrophobic n‐octyl alkyl chain, the hydrophilic tri(ethylene glycol) (TEG) chain and the thermo‐cleavable tert‐butoxycarbonyl (t‐Boc) carbamate group. In spite of having identical conjugated chromophore and chiral appendages, in aggregated form the three dyes displayed profoundly different optical, chiroptical, electrochemical and thermal features. ECD measurements revealed differences in the aggregation modes, which would be inaccessible by most other techniques. We found strong chiroptical features, which would have major implications in the context of chiral organic opto‐electronics and in the development of other highly innovative technological applications. [ABSTRACT FROM AUTHOR]

Organic dyes with strong absorption in the near‐infrared (NIR) region are potentially useful in medical applications, such as tumor imaging and photothermal therapy. In this work, new NIR dyes combining BAr2‐bridged azafulvene dimer acceptors with diarylaminothienyl donors in a donor–acceptor–donor configuration were synthesized. Surprisingly, it was found that in these molecules the BAr2‐bridged azafulvene acceptor adopts a 5‐membered, rather than 6‐membered ring structure. The influence of the aryl substituents on the HOMO and LUMO energy levels of the dye compounds was assessed from electrochemical and optical measurements. Strong electron‐withdrawing fluorinated substituents (Ar=C6F5, 3,5‐(CF3)2C6H3) lowered the HOMO energy while preserving the small HOMO–LUMO energy gap, resulting in promising NIR dye molecules that combine strong absorption bands centered around 900 nm with good photostability. [ABSTRACT FROM AUTHOR]

A series of new organic donor–π–acceptor dyes incorporating a diquat moiety as a novel electron‐acceptor unit have been synthesized and characterized. The analytical data were supported by DFT calculations. These dyes were explored in the aerobic thiocyanation of indoles and pyrroles. Here they showed a high photocatalytic activity under visible light, giving isolated yields of up to 97 %. In addition, the photocatalytic activity of standalone diquat and methyl viologen through formation of an electron donor acceptor complex is presented. [ABSTRACT FROM AUTHOR]

The yolk‐shell Co3O4@Fe3O4/C nanocomposites with Co3O4 as the core, Fe3O4/C as the shell, and a cavity structure were synthesized by the hard template method. The physical and chemical properties of the composites were characterized by SEM, TEM, XRD, TGA, XPS, BET, and VSM. The specific surface area of yolk‐shell Co3O4@Fe3O4/C nanocomposites is 175.9 m2 g−1, showing superparamagnetic properties. The yolk‐shell Co3O4@Fe3O4/C nanocomposites were used as heterogeneous Fenton catalysts to activate peroxymonosulfate (PMS) to degrade MB, which showed high catalytic degradation performance. The degradation rate of MB reached 100 % within 30 min under the circumstances of the yolk‐shell Co3O4@Fe3O4/C nanocomposites dosage of 0.1 g L−1, the PMS dosage of 1.0 g L−1, the initial MB concentration of 100 mg L−1, an initial pH of 5.5, and a temperature of 30±2 °C. The enhanced catalytic performance of the yolk‐shell Co3O4@Fe3O4/C nanocomposites can be attributed to the synergistic effect of the two catalytically active materials and the middle cavity. The effects of different operating parameters and co‐existing anion species on MB degradation were also investigated. Electron paramagnetic resonance (EPR) analysis and quenching experiments confirmed that the formation of SO4⋅− in the yolk‐shell Co3O4@Fe3O4/C/PMS system contributes to MB degradation. In addition, yolk‐shell Co3O4@Fe3O4/C nanocomposites can be easily separated from the pollutant solution under the action of an external magnetic field, and the degradation rate of MB can still reach 98 % after five cycles, indicating that it has good stability and reusability and has broad application prospects in the field of water purification. [ABSTRACT FROM AUTHOR]

Expansion microscopy (ExM) has been widely used to detect biomolecules in cultured cells and tissue samples due to its enablement of super resolution imaging with conventional microscopes, via physical expansion of samples. However, reaction conditions inherent to the process bring about strong fluorescent signal loss during polymerization and digestion and thus limit the brightness of the signal obtained post expansion. Here, we explore the impact of stabilizer‐containing organic fluorophores in ExM, as a mitigation strategy for this radical‐induced dye degradation. Through direct conjugation of 4‐nitrophenylalanine (NPA) to our previously developed trifunctional reagents, we validate and demonstrate that these multifunctional linkers enable visualization of different organelles with improved fluorescent intensity, owning to protection of the dyes to radical induced degradation as well as to photoprotection upon imaging. At this point, we cannot disentangle the relative contribution of both mechanisms. Furthermore, we report anchoring linkers that allow straightforward application of NPA or Trolox to commercially available fluorophore‐conjugated antibodies. We show that these anchoring linkers enable complete retention of biological targets while increasing fluorophore photostability. Our results provide guidance in exploring these stabilizer‐modified agents in ExM and methods for increased signal survival through the polymerization steps of the ExM protocols. [ABSTRACT FROM AUTHOR]

Octaazaperopyrenedioxides (OAPPDOs) are a new class of fluorescent polycyclic aromatic hydrocarbons based on a tetraazaperylene core that is formally condensed with N‐substituted urea units in the two opposite peri positions. Here, we report the synthesis of series of substituted OAPPDO derivatives with different N‐substitution patterns (H, alkyl, benzyl) in the peri positions, including bay‐chlorinated OAPPDOs. Starting from the latter, a series of bay‐arylated OAPPDOs was synthesized by Suzuki cross coupling, which resulted in the formation of helically chiral OAPPDO derivatives. The electrochemical and photophysical properties were investigated by UV/Vis and fluorescence spectroscopy as well as cyclic voltammetry. The P and M enantiomers of a phenylated OAPPDO were separated by semipreparative HPLC and further analyzed by CD spectroscopy. The frontier orbital energies, the mechanism of the isomerization, the electronic excitation and the CD spectrum (TD‐DFT) were computed and compared to the experimental data. The reversible 1e− oxidation of the OAPPDOs generates the corresponding radical cations, one of which was characterized by EPR spectroscopy. The reversible oxidation process was also systematically investigated by spectro‐electrochemistry. [ABSTRACT FROM AUTHOR]

The combination of high crystallinity and rich host‐guest chemistry in metal‐organic frameworks (MOFs), have situated them in an advantageous position, with respect to traditional porous materials, to gain insight on specific weak noncovalent supramolecular interactions. In particular, sulfur σ‐hole interactions are known to play a key role in the biological activity of living beings as well as on relevant molecular recognitions processes. However, so far, they have been barely explored. Here, we describe both how the combination of the intrinsic features of MOFs, especially the possibility of using single‐crystal X‐ray crystallography (SCXRD), can be an extremely valuable tool to gain insight on sulfur σ‐hole interactions, and how their rational exploitation can be enormously useful in the efficient removal of harmful organic molecules from aquatic ecosystems. Thus, we have used a MOF, prepared from the amino acid L‐methionine and possessing channels decorated with −CH2CH2SCH3 thioalkyl chains, to remove a family of organic dyes at very low concentrations (10 ppm) from water. This MOF is able to efficiently capture the four dyes in a very fast manner, reaching within five minutes nearly the maximum removal. Remarkably, the crystal structure of the different organic dyes within MOFs channels could be determined by SCXRD. This has enabled us to directly visualize the important role sulfur σ‐hole interactions play on the removal of organic dyes from aqueous solutions, representing one of the first studies on the rational exploitation of σ‐hole interactions for water remediation. [ABSTRACT FROM AUTHOR]

It is still challenging to realize a dual‐emission system, in which two luminescent bands simultaneously appear by photoexcitation, in solid with organic dyes due to the difficulty in regulation of electronic properties in the excited state and concentration quenching. o‐Carborane is known to be a versatile platform for constructing solid‐state emitters since the sphere boron cluster is favorable for suppressing intermolecular interactions and subsequently concentration quenching. Here, we show solid‐state dual‐emissive o‐carborane derivatives. We prepared 4 types of o‐carborane derivatives and found dual‐emission behaviors both in solution and solid states. By regulating the rotation at the o‐carborane unit with the intramolecular CcageH⋅⋅⋅O interaction, the dual‐emission intensity ratios were changed. Finally, it was demonstrated that the overall photoluminescence spectra can be estimated using the binding energy of intramolecular interactions. [ABSTRACT FROM AUTHOR]

Ortho substituted octaazaperopyrenes (OAPPs) are a new class of functional dyes characterized by their strong electron‐accepting behavior. Herein, the synthesis, as well as the electrochemical and photo physical properties of an OAPP dye, is reported. The OAPP target was prepared via selective nucleophilic substitution at the peri position of a bay chlorinated tetraazaperylene by introduction of four amino‐substituents. The resulting tetraminoperylene was reacted with different acyl chlorides and anhydrides to give the twisted bay chlorinated OAPP derivatives which were isolated in their reduced dihydro‐form. The OAPP target could be obtained via a palladium catalyzed dehalogenation and a subsequent oxidation. The eightfold isosteric [CH→N] replacement within the peropyrene core structure results in a large decrease of the frontier orbital energies, rendering the target compound a potent oxidant while preserving the planarity of the aromatic core. The radical anion was obtained by reduction of the OAPP with KC8 and characterized by EPR spectroscopy. A general discussion of the number and location of [CH→N] replacements in peropyrene structures and their frontier orbital energies is provided. [ABSTRACT FROM AUTHOR]

Polymorphism control of metal‐organic frameworks is highly desired for elucidating structure‐property relationships, but remains an empirical process and is usually done in a trial‐and‐error approach. We adopted the rarely used actinide cation Th4+ and a ditopic linker to construct a series of thorium‐organic frameworks (TOFs) with a range of polymorphs. The extraordinary coordination versatility of Th4+ cations and clusters, coupled with synthetic modulation, gives five distinct phases, wherein the highest degree of interpenetration (threefold) and porosity (75.9 %) of TOFs have been achieved. Notably, the O atom on the capping site of the nine‐coordinated Th4+ cation can function as a bridging unit to interconnect neighboring secondary building units (SBUs), affording topologies that are undocumented for other tetravalent‐metal‐containing MOFs. Furthermore, for the first time HCOOH has been demonstrated as a bridging unit of SBUs to further induce structural complexity. The resulting TOFs exhibit considerably different adsorption behaviors toward organic dyes, thus suggesting that TOFs represent an exceptional and promising platform for structure‐property relationship study. [ABSTRACT FROM AUTHOR]

Upconversion luminescent (UCL) triggered photodynamic therapy (PDT) affords superior outcome for cancer treatment. However, conventional UCL materials which all work by a multiphoton absorption (MPA) process inevitably need extremely high power density far over the maximum permissible exposure (MPE) to laser. Here, a one‐photon absorption molecular upconversion sensitizer Cy5.5‐Br based on frequency upconversion luminescent (FUCL) is designed for PDT. The unusual super heavy atom effect (SHAE) in Cy5.5‐Br strongly enhances its spin‐orbit coupling (0.23 cm−1), triplet quantum yield (11.1 %) and triplet state lifetime (18.8 μs) while the potential hot‐band absorption of Cy5.5‐Br is well maintained. Importantly, Cy5.5‐Br can efficiently target the tumour site and kill cancer cells by destroying mitochondria under a biosafety MPE to 808 nm laser. The photostability and antitumor results are obviously superior to that of a Stokes process. This work provides a design criterion for FUCL dyes to realize effective PDT upon a biosafety optical density, possibly bringing more clinical benefits than conventional MPA materials. [ABSTRACT FROM AUTHOR]

Fabricating structural complex assemblies from simple amino acid‐based derivatives is attracting great research interests due to their easy accessibility and preparation. However, the morphological regulation of racemates (an equimolar mixture of enantiomers) were largely overlooked. In this work, through rational modulation of kinetic and thermodynamic parameters, we achieved multiple dimensional architectures employing tryptophan‐based racemate (RPWM). Upon assembling, 1D bundled nanofibers, 2D lamellar nanostructure and 3D urchin‐like microflowers could be obtained depending on the solvents used. The corresponding morphology evolutions were successfully illustrated by changing the enantiomeric excess (ee) value. Moreover, for RPWM, uniform 0D nanospheres were formed in H2O under 4 °C, which could spontaneously convert into lamella under ambient temperature. Taking advantages of its temperature‐responsive phase change behavior, RPWM assemblies exhibited excellent removal efficiency for organic dye RhB, and could be reused for several consecutive cycles without significant changes in its removal performance. Taken together, it's rational to envision that the engineering of racemates assembly pathways can greatly increase the robustness in a wide variety of supramolecular materials and further lead to their blooming versatile applications. [ABSTRACT FROM AUTHOR]

Despite recent extensive studies on mechanochromic luminescence (MCL), rational control over the magnitude of the emission‐wavelength shift in response to mechanical stimuli remains challenging. In the present study, a two‐component donor‐acceptor approach has been applied to create a variety of organic MCL composites that exhibit remarkable emission‐wavelength switching. Dibenzofuran‐based bis(1‐pyrenylmethyl)diamine and typical organic fluorophores have been employed as donor and acceptor dyes, respectively. Outstanding wide‐range MCL with an emission‐wavelength shift of over 300 nm has been achieved by mixing the diamine with 3,4,9,10‐perylenetetracarboxylic diimide. Unprecedented two‐step MCL in response to mechanical stimuli of different intensity has also been realized for a two‐component mixture with 9,10‐anthraquinone. Fluorescence microscopy observations at the single‐particle level revealed that the segregation and mixing of the two‐component dyes contribute to the stimuli‐responsive emission‐color switching of the MCL composites. [ABSTRACT FROM AUTHOR]

The synthesis of 2,9‐diaza‐1,3,8,10‐tetratriflato‐dibenzoperylene (DDP 3 a) and corresponding 2,9‐dimethyl‐1,3,8,10‐tetratriflato‐dibenzoperylene (DBP 3 b) has been developed at multigram scale via reduction of one of the industrially most important high‐performance dyes, perylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI), and of the corresponding dihydroxy peropyrenequinone precursor. The focus of this paper is on the reactivity pattern of 3 a as key intermediate towards highly functionalized 2,9‐diazadibenzopyrelenes (DDPs) obtained via catalytic substitution of four triflate by aryl, heteroaryl, alkynyl, aminyl, and O‐phosphanyl substituents. The influence of electron‐donating substituents (OSiMe3, OPt‐Bu2, N‐piperidinyl), electron‐withdrawing (OTf, 3,5‐bis‐trifluoromethyl‐phenyl), and of electron‐rich π‐conjugated (2‐thienyl, 4‐tert‐butylphenyl, trimethylsilyl‐ethynyl) substituents on optoelectronic and structural properties of these functionalized DDPs has been investigated via XRD analyses, UV/Vis, PL spectroscopy, and by electroanalytical CV. These results were correlated to results of DFT and TD‐DFT calculations. Thus, functionalized DPPs with easily tunable HOMO and LUMO energies and gap became available via a new and reliable synthetic strategy starting from readily available PTCDI. [ABSTRACT FROM AUTHOR]

Three diketopyrrolo[3,4- I c i ]pyrrole-1,2,3-1 I H i -triazole (DPP) dyes bearing the same chiral appendage R* but decorated with different achiral substituent groups Y showed profoundly different optical, chiroptical, electrochemical and thermal features in their aggregated form. Keywords: chirality; diketopyrrolopyrroles; organic dyes; supramolecular chemistry; triazoles EN chirality diketopyrrolopyrroles organic dyes supramolecular chemistry triazoles 1 1 1 06/21/23 20230619 NES 230619 B Supramolecular chirality b is far from being determined only by local stereogenic elements. Chirality, diketopyrrolopyrroles, organic dyes, supramolecular chemistry, triazoles. [Extracted from the article]