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A new concept for the regioselective synthesis of Hamilton‐receptor and cyanurate‐functionalized oligo adducts of the fullerene C60 was developed. Based on an in‐situ deprotection and click‐post‐functionalization approach with novel azido precursors, the corresponding fullerene hexakis‐adducts with octahedral addition patterns and up to twelve Hamilton‐receptor/cyanurate moieties surrounding the fullerene sphere were synthesized. The versatility of this approach was further demonstrated by the synthesis of Hamilton‐receptor/cyanurate functionalized fullerene mono‐adducts, which are not accessible by direct cyclopropanation. Several fullerene target compounds were purified by simple washing procedures of the solid crude reaction mixture without the need for chromatography. The resulting fullerene mono‐ and hexakis‐adducts were fully characterized and their supramolecular properties were investigated by NMR‐spectroscopy and isothermal titration calorimetry (ITC). [ABSTRACT FROM AUTHOR]

In this work, we introduce lead-free organic ferroelectric perovskite N-methyl-N′-diazabicyclo[2.2.2]octonium)–ammonium triiodide (MDABCO-NH4I3) nanocrystals embedded in three different polymer fibers fabricated by the electrospinning technique, as mechanical energy harvesters. Molecular ferroelectrics offer the advantage of structural diversity and tunability, easy fabrication, and mechanical flexibility. Organic–inorganic hybrid materials are new low-symmetry emerging materials that may be used as energy harvesters because of their piezoelectric or ferroelectric properties. Among these, ferroelectric metal-free perovskites are a class of recently discovered multifunctional materials. The doped nanofibers, which are very flexible and have a high Young modulus, behave as active piezoelectric energy harvesting sources that produce a piezoelectric voltage coefficient up to geff = 3.6 VmN−1 and show a blue intense luminescence band at 325 nm. In this work, the pyroelectric coefficient is reported for the MDABCO-NH4I3 perovskite inserted in electrospun fibers. At the ferroelectric–paraelectric phase transition, the embedded nanocrystals display a pyroelectric coefficient as high as 194 × 10−6 Cm−2k−1, within the same order of magnitude as that reported for the state-of-the-art bulk ferroelectric triglycine sulfate (TGS). The perovskite nanocrystals embedded into the polymer fibers remain stable in their piezoelectric output response, and no degradation is caused by oxidation, making the piezoelectric perovskite nanofibers suitable to be used as flexible energy harvesters. [ABSTRACT FROM AUTHOR]

N,N-dimethyl-4-nitroaniline is a piezoelectric organic superplastic and superelastic charge transfer molecular crystal that crystallizes in an acentric structure. Organic mechanical flexible crystals are of great importance as they stand between soft matter and inorganic crystals. Highly aligned poly-l-lactic acid polymer microfibers with embedded N,N-dimethyl-4-nitroaniline nanocrystals are fabricated using the electrospinning technique, and their piezoelectric and optical properties are explored as hybrid systems. The composite fibers display an extraordinarily high piezoelectric output response, where for a small stress of 5.0 × 103 Nm−2, an effective piezoelectric voltage coefficient of geff = 4.1 VmN−1 is obtained, which is one of the highest among piezoelectric polymers and organic lead perovskites. Mechanically, they exhibit an average increase of 67% in the Young modulus compared to polymer microfibers alone, reaching 55 MPa, while the tensile strength reaches 2.8 MPa. Furthermore, the fibers show solid-state blue fluorescence, important for emission applications, with a long lifetime decay (147 ns) lifetime decay. The present results show that nanocrystals from small organic molecules with luminescent, elastic and piezoelectric properties form a mechanically strong hybrid functional 2-dimensional array, promising for applications in energy harvesting through the piezoelectric effect and as solid-state blue emitters. [ABSTRACT FROM AUTHOR]

The continuous increase in the global energy demand deeply impacts the environment. Consequently, the research is moving towards more sustainable forms of energy production, storage and saving. Suitable technologies and materials are fundamental to win the challenge towards a greener and more eco-friendly society. Organic π-conjugated materials, including small molecules, oligomers and polymers are a wide and versatile class of functional materials with great potentiality, as they can be used as active matrixes in the fabrication of lightweight, flexible, cheap and large area devices. Their chemical and physical properties, both at a molecular level and mainly in the solid state, are a result of many factors, strictly related to the conjugated structure and functional groups on the backbone, which control the intermolecular forces driving solid state aggregations. The synthesis, through the molecular design, the choice of conjugated backbone and functionalization, represents the first and most powerful tool for finely tuning the chemico-physical properties of organic materials tailored for specific applications. In the present review, we report an overview of our works focused on synthetic methodologies, characterization, structure-properties correlation studies and applications of organic materials designed for energy-involving solid-state applications, organic photovoltaics in particular. The impact of functionalization on electro-optical properties and performance in device are discussed, also in relation to the specific applications. [ABSTRACT FROM AUTHOR]

Abstract Perylene dyes have transcended their role as simple colorants and have been reinvigorated as functional dyes. Based on the substitution at the peri-position by six-membered carboxylic imides, the perylene family is principally embellished with perylene diimides (PDIs) and perylene monoimides (PMIs). Perylene dyes are widely acclaimed and adorned on account of their phenomenal thermal, chemical, and photostability juxtaposed with their high absorption coefficient and near-unity fluorescence quantum yield. Although symmetric PDIs have always been in the limelight, their asymmetrical counterpart PMI is already rubbing shoulders, thanks to the consistent efforts of several scientific minds. Recently, there has been an upsurge in engendering PMI-based versatile organic architectures decked with intriguing photophysical properties and pertinent applications. In this review, the synthesis and photophysical features of various PMI-based derivatives along with their relevant applications in the arena of organic photovoltaics, photocatalysis, self-assembly, fluorescence sensing, and bio-imaging are accrued and expounded, hoping to enlighten the less delved but engrossing realm of PMIs. Table of content: 1 Introduction 2 Advantages of PMI over PDI 3 Challenges in Working with PMI and Ways to Overcome 4 Various Aspects of Reactivity of Different Positions 5 Synthesis of the PMI core 6 Synthesis of PMI Derivatives 6.1 Bromination of PMI 6.2 Synthesis of PMI Derivatives using Coupling Reactions 6.2.1 Suzuki Coupling 6.2.2 Sonogashira Coupling 6.2.3 Buchwald–Hartwig Coupling Reaction 6.3 Nucleophilic Substitution Reactions 6.4 Peri-Annulation Reaction 7 Photophysical Properties of PMI 8 Singlet Fission Properties 9 Förster Resonance Energy Transfer with PMI 10 Symmetry Breaking Charge Transfer Properties 11 Panchromatic Light Absorption Properties of PMI 12 Acid/Base Sensitivity of PMI 13 NIR-Absorbing PMI 14 Achieving of Triplet State Using PMI 15 Solid-State Emissive PMI 16 Thermo-Responsive Materials with PMI 17 Photo-Responsive PMI Derivatives 18 Electrochemical Properties of Rylene Derivative 19 Self-Assembling Properties of PMI Derivatives 20 Applications of PMI in Solar Cells 21 PMIs in Bulk Heterojunction Solar Cells 22 PMIs in Dye-Sensitized Solar Cells 23 PMI as a Fluorescent Reporter 23.1 Application of PMI Derivatives for Bio-Imaging 23.2 Hydrophilic PMIs for Bio-Imaging 23.3 Aggregated PMI as NIR-Emissive Fluoroprobe for Bio-Imaging 24 Photocatalytic Hydrogen Generation using PMI 25 PMI-Based Organocatalysis 26 PMI Derivatives for Single-molecule Spectroscopy 27 Host–Guest Chemistry with PMI 28 Conclusions and Outlook

Abstract Covalent organic frameworks (COFs) are an advanced class of crystalline porous polymers that have garnered significant interest due to their tunable properties and robust molecular architectures. As a result, COFs with energy-storage properties are of particular interest to the field of rechargeable battery electrode materials. However, investigation into COFs as candidates for energy-storage materials is still in its infancy. This review will highlight methods used to fabricate COFs used as electrode materials and discuss the factors that prove critical for their production. A collection of known COF-based energy-storage systems will be featured. In addition, the ability to utilize the storage properties of COFs for systems beyond traditional Li-ion batteries will be addressed. An outlook will address the current progress and remaining challenges facing the field to ultimately expand the scope of their applications.

Attachment of cyclic imide groups to polycyclic aromatic hydrocarbons (PAHs) leads to fascinating electronic and luminescence properties, with rylene diimides being a representative example. The close to unity fluorescence quantum yields and electron-acceptor properties render them suitable for application in organic electronics and photovoltaics. Recent reports show that, in line with planar PAHs, the imide functionalization has also endowed helical three-dimensional PAHs with similar beneficial photophysical properties. In this article, we have summarized the state-of-the-art research developments in the field of helicene–imide hybrid functional molecules, with a particular focus on synthesis, (chir)optical and redox properties, and applications in electronics. Additionally, we have highlighted our recent work, introducing a novel family of functional chiral molecules, namely, [ n ]helicene diimides, as three-dimensional relatives of rylene diimides. [ABSTRACT FROM AUTHOR]

In this work, we introduce lead-free organic ferroelectric perovskite N-methyl-N′-diazabicyclo[2.2.2]octonium)–ammonium triiodide (MDABCO-NH4I3) nanocrystals embedded in three different polymer fibers fabricated by the electrospinning technique, as mechanical energy harvesters. Molecular ferroelectrics offer the advantage of structural diversity and tunability, easy fabrication, and mechanical flexibility. Organic–inorganic hybrid materials are new low-symmetry emerging materials that may be used as energy harvesters because of their piezoelectric or ferroelectric properties. Among these, ferroelectric metal-free perovskites are a class of recently discovered multifunctional materials. The doped nanofibers, which are very flexible and have a high Young modulus, behave as active piezoelectric energy harvesting sources that produce a piezoelectric voltage coefficient up to geff = 3.6 VmN−1 and show a blue intense luminescence band at 325 nm. In this work, the pyroelectric coefficient is reported for the MDABCO-NH4I3 perovskite inserted in electrospun fibers. At the ferroelectric–paraelectric phase transition, the embedded nanocrystals display a pyroelectric coefficient as high as 194 × 10−6 Cm−2k−1, within the same order of magnitude as that reported for the state-of-the-art bulk ferroelectric triglycine sulfate (TGS). The perovskite nanocrystals embedded into the polymer fibers remain stable in their piezoelectric output response, and no degradation is caused by oxidation, making the piezoelectric perovskite nanofibers suitable to be used as flexible energy harvesters.

N,N-dimethyl-4-nitroaniline is a piezoelectric organic superplastic and superelastic charge transfer molecular crystal that crystallizes in an acentric structure. Organic mechanical flexible crystals are of great importance as they stand between soft matter and inorganic crystals. Highly aligned poly-l-lactic acid polymer microfibers with embedded N,N-dimethyl-4-nitroaniline nanocrystals are fabricated using the electrospinning technique, and their piezoelectric and optical properties are explored as hybrid systems. The composite fibers display an extraordinarily high piezoelectric output response, where for a small stress of 5.0 × 103 Nm−2, an effective piezoelectric voltage coefficient of geff = 4.1 VmN−1 is obtained, which is one of the highest among piezoelectric polymers and organic lead perovskites. Mechanically, they exhibit an average increase of 67% in the Young modulus compared to polymer microfibers alone, reaching 55 MPa, while the tensile strength reaches 2.8 MPa. Furthermore, the fibers show solid-state blue fluorescence, important for emission applications, with a long lifetime decay (147 ns) lifetime decay. The present results show that nanocrystals from small organic molecules with luminescent, elastic and piezoelectric properties form a mechanically strong hybrid functional 2-dimensional array, promising for applications in energy harvesting through the piezoelectric effect and as solid-state blue emitters.

The continuous increase in the global energy demand deeply impacts the environment. Consequently, the research is moving towards more sustainable forms of energy production, storage and saving. Suitable technologies and materials are fundamental to win the challenge towards a greener and more eco-friendly society. Organic π-conjugated materials, including small molecules, oligomers and polymers are a wide and versatile class of functional materials with great potentiality, as they can be used as active matrixes in the fabrication of lightweight, flexible, cheap and large area devices. Their chemical and physical properties, both at a molecular level and mainly in the solid state, are a result of many factors, strictly related to the conjugated structure and functional groups on the backbone, which control the intermolecular forces driving solid state aggregations. The synthesis, through the molecular design, the choice of conjugated backbone and functionalization, represents the first and most powerful tool for finely tuning the chemico-physical properties of organic materials tailored for specific applications. In the present review, we report an overview of our works focused on synthetic methodologies, characterization, structure-properties correlation studies and applications of organic materials designed for energy-involving solid-state applications, organic photovoltaics in particular. The impact of functionalization on electro-optical properties and performance in device are discussed, also in relation to the specific applications.

A new concept for the regioselective synthesis of [3 : 2 : 1] hexakis‐adducts of fullerene C60 was developed. Based on sequential tether‐directed remote functionalizations, chiral [3 : 2] pentakis‐adducts with an incomplete octahedral addition pattern were synthesized via stepwise cyclopropanation of C60 with suitable macrocyclic tri‐ and bifunctional cyclomalonate tethers. The four resulting stereoisomers were isolated using chiral HPLC. The corresponding pairs of enantiomers show mirror image behavior in their CD‐spectra. The pentakis‐adducts served as suitable building blocks for the spatially controlled synthesis of mixed hexakis‐adducts. Implementation of functional group‐bearing monomalonates afforded octahedral [3 : 2 : 1] hexakis‐adducts suitable for the construction of larger molecular and supramolecular fullerene architectures in excellent yield. [ABSTRACT FROM AUTHOR]

Organic Near‐Infrared luminophores have found broad application as functional materials, but the development of efficient NIR emitters is still a challenging goal. Here we report on a new class of thieno[3,4‐b]pyrazine‐based NIR emitting materials with Aggregation Induced Emission (AIE) properties. The dyes feature a donor–acceptor–donor (D−A−D) structure, with a thienopyrazine acceptor core connected to two triarylamine donor groups bearing a tetraphenylethylene (TPE) moiety. Fast and efficient synthesis allowed the modular preparation of three dyes of tunable absorption and emission profiles. These constructs were extensively characterized by spectroscopic studies in different solvents, which revealed intense light‐harvesting ability and emissions in the deep‐red and NIR region with large Stokes shift values. Remarkably, the dyes exhibited AIE properties, retaining emissive ability in the aggregate state, thus emerging as attractive materials for their potential application in the development of luminescent devices.Novel NIR‐emitting organic dyes with aggregation‐induced emission (AIE) properties are described. The thienopyrazine‐based donor‐acceptor‐donor structure allows for easy tuning of the photophysical properties. The intense light absorption ability and the emission in the red/NIR region, both in solution and in the aggregate phase, make them attractive for potential use as functional organic materials in the development of luminescent devices. [ABSTRACT FROM AUTHOR]

Compounds based on two (11-oxoanthra[1,2-b]thiophene-6-ylidene)dipropanedinitrile moieties joined by a fluorene or phenyl π-linker are investigated as potential substitutes for fullerene acceptors in active layers of organic photovoltaics. The effect a linker has on the optical and morphological properties of conjugated polymeric composites and synthesized compounds, and on the photovoltaic parameters of a cell, is revealed. The values obtained for the coefficient of power conversion efficiency (PCE) are 0.047 and 0.028%, respectively, for compounds with fluorene and phenyl linkers, respectively. [ABSTRACT FROM AUTHOR]

The preparation and characterization of 12 azaindolo[3,2,1‐jk]carbazoles is presented. Ring‐closing C−H activation allowed for the convenient preparation of six singly and six doubly nitrogen‐substituted indolo[3,2,1‐jk]carbazole derivatives in which ten of the materials have not been described in the literature before. The detailed photophysical and electrochemical characterization of the developed materials revealed a significant impact of the incorporation of pyridine‐like nitrogen into the fully planar indolo[3,2,1‐jk]carbazole backbone. Furthermore, the nitrogen position decisively impacted intermolecular hydrogen bonding and thus the solid‐state alignment. Ultimately, the versatility of the azaindolo[3,2,1‐jk]carbazoles scaffold makes this class of materials an attractive new building block for the design of functional organic materials. Property tuning by nitrogen incorporation: a reliable synthetic protocol for the preparation of novel azaindolo[3,2,1‐jk]carbazole derivatives was established. Nitrogen position and amount decisively impacted photophysical and electrochemical properties as well as supramolecular arrangement. [ABSTRACT FROM AUTHOR]

Efficient synthetic routes that combine different palladium‐catalyzed cross‐coupling reactions have been developed for the preparation of a new family of push‐pull derivatives in which pyridine was used as the acceptor group and different para‐substituted diphenylamines as the donor groups. All compounds showed absorption in the UV/Vis region and blue‐green emission with high quantum yields. Significant red shifts were observed in the absorption and fluorescence emission maxima on increasing the electron‐donating ability of the substituents or on incorporating a π‐conjugated linker. This finding can be explained on the basis of enhanced intramolecular charge transfer (ICT). Strong emission solvatochromism confirmed the formation of an intramolecular charge‐separated emitting state. The HOMO‐LUMO energy gaps have been estimated by experimental electrochemical measurements and the results were interpreted with the aid of DFT calculations. The thermal behavior of all materials has also been studied by differential scanning calorimetry. A series of push‐pull chromophores with a pyridine electron‐withdrawing fragment and methoxy‐, 9H‐carbazol‐9‐yl‐, and 5‐methoxythiophen‐2‐yl‐substituted diphenylamino groups as electron‐donating units was designed. [ABSTRACT FROM AUTHOR]

A modular synthesis of multi‐functionalized biphenyl, terphenyl and higher linear oligophenylene dicarboxylic acids and pyridine‐terminated oligoarenes by stepwise palladium–catalyzed borylation/Suzuki–Miyaura cross‐coupling reactions is described. The presence of several distinct functional groups such as azide, hydroxy, and alkyne, as well as coordinative functional end groups (carboxylic acid or pyridine) combined in a single oligoarene molecular unit at strategic positions offer an advantageous dual‐utility. First, these compounds can serve as useful molecular bricks (ditopic organic linkers) in the construction of complex porous crystalline materials. Second, after the assembly into the crystalline coordination networks, orthogonal functional sites within the linker‐backbone offer tremendous potential from application perspectives as they can be modified by a wide range of post‐synthetic modifications including azide–alkyne click chemistry. This allows further tailoring of the supramolecular assemblies to yield novel multifunctional materials. Diversely functionalized biphenyl, terphenyl and higher linear oligo(hetero)arenes can be synthesized by using a modular approach consisting of palladium‐catalyzed borylation and Suzuki–Miyaura cross‐coupling reactions. These ditopic organic linkers can be used for growing porous crystalline materials, such as MOFs, SURMOFs, SURGELs. Diverse functional groups (azide, alkyne) offer anchor points for post‐synthetic modification of such materials. [ABSTRACT FROM AUTHOR]

A simple protocol for the controlled preparation of mono‐ and diprotonated hydroporphyrins (chlorins) is presented. The chlorins carried 10‐aryl groups with electron‐neutral (phenyl), electron‐donating (p‐OMe‐C6H4) or electron‐withdrawing (pentafluorophenyl) substituents. The protonation reactions were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first (4.8–5.3) and second pKa's (1.7–0.5). Both mono‐ and diprotonated species were fully characterized by 1H NMR spectroscopy, which, in combination with theoretical studies, showed that these macrocycles were significantly distorted in solution. A 10‐phenyl‐substituted monoprotonated chlorin was characterized by X‐ray crystallography. This is the first structurally characterized hydroporphyrin monocation, and the first crystal structure of a sterically unencumbered singly protonated tetrapyrrole. The photostabilities of the mono‐ and diprotonated 10‐phenylchlorins were measured upon irradiation into their Soret bands; protonation yielded increased photostabilities. The controlled stepwise mono‐ and diprotonation of synthetic hydroporphyrins carrying is reported. Protonations were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first and second pKa's. Both mono‐ and diprotonated species were significantly distorted in solution. A monoprotonated chlorin was characterized by X‐ray crystallography. [ABSTRACT FROM AUTHOR]

In an effort to see the effect of conjugation length and substitution at different positions of N‐phenylcarbazole, herein we have designed and synthesized symmetrical and unsymmetrical acetylene bridged N‐phenylcarbazole‐based diketopyrrolopyrroles (DPPs 5–9) by the Pd‐catalyzed Sonogashira cross‐coupling and Stille coupling reactions. A comparative study of isomeric N‐phenylcarbazole (meta‐ and para‐isomers) attached to the DPP is performed. The N‐phenylcarbazole‐based DPP monomers (5–7, 10 and 11) exhibit absorption in the visible region, whereas the corresponding dimers (8 and 9) show broad absorption towards the near‐infrared (NIR) region with lowering of the HOMO–LUMO gap. The para‐N‐phenylcarbazole‐based DPPs (8, 10, and 11) show red shifted absorption compared to their meta‐substituted analogues (9, 5, and 6). The emission spectra reveal that DPP monomers (5–7) are fluorescent in nature, whereas quenching of fluorescence was observed in DPP dimers (8 and 9). The thermogravimetric analysis shows higher thermal stability for meta‐N‐phenylcarbazole‐based DPPs as compared to their para‐based analogues. Monomers of carbazole‐based DPPs are thermally more stable than their dimers. The electrochemical study reveals multiple oxidation waves related to donor moieties (such as thiophene and carbazole) and one reduction wave corresponding to the DPP unit. We have designed and synthesized symmetrical and unsymmetrical acetylene bridged N‐phenylcarbazole‐based diketopyrrolopyrroles by Pd‐catalyzed cross‐coupling reactions. The monomers exhibit absorption in the visible region, whereas the corresponding dimers show broad absorption towards near‐infrared (NIR) region with lowering of the HOMO–LUMO gap. These materials showed good thermal stability. [ABSTRACT FROM AUTHOR]

A novel series of 2‐coumarin‐3‐yl‐imidazo[1,2‐a]pyrimidines have been synthesized with functionalized coumarin and pyrimidine units of the different architecture to give various fluorescent compounds. A new additional series bearing unsubstituted coumarin and 7‐dialkylaminocoumarin as fluorophore were obtained by palladium‐catalyzed cross‐coupling reactions, through coupling of 6‐bromo‐2‐coumarin‐3‐yl‐imidazopyrimidine derivatives with various arylboronic acids. In the all reaction step, microwave irradiation (MWI) method was used and compared with the conventional method (CM). Photophysical properties of synthesized compounds were studied by a combination of UV/Vis and fluorescence spectroscopy in various solvents having different polarities. The protonation abilities of all compounds were investigated by titration with trifluoroacetic acid (TFA) in dichloromethane. In both series, the compounds bearing 7‐dialkylaminocoumarin are fluorescently active even in daylight and showed maximum absorption wavelengths (λabs–max) in the visible region in all solvents used. In addition, they showed drastic color and emission change in acidic environment. Moreover, for the investigation of protonation ability of three selected compounds bearing 7‐dialkylaminocoumarin have been studied using a buffer solution with various pH and determinated their pKa values. The compound bearing morpholine has the potential to use as colorimetric and luminescence pH sensor. The thermal properties of all the synthesized compounds were also evaluated with TGA to test their usability as optic dyes. The design and synthesis of 2‐coumarin‐3‐yl‐imidazo[1,2‐a]pyrimidine derivatives as novel pH sensitive dyes are described. The photophysical properties and protonation abilities of these dyes were investigated for their using as fluorescent pH chemosensor in aqueous solution. [ABSTRACT FROM AUTHOR]

We synthesized solvatochromic thiol‐reactive fluorescent probes 6FM‐M and 7AFM‐M possessing two‐band emission. 7AFM‐M was designed to have a smaller dipole moment than 6FM‐M and as a result it showed better separation of the two emission bands. Both probes were used to label a cysteine mutant of α‐synuclein (αSyn), a presynaptic neuronal protein associated with Parkinson's disease. We investigated the ability of the probes to sense αSyn binding to lipid membranes and αSyn fibrillization, and compared their sensitivity with that of one‐band solvatochromic probes. We found that while all the tested probes can discriminate two αSyn states, only the 7AFM‐M probe is able to clearly discriminate all three protein states of αSyn: unstructured, membrane‐bound and fibrillar αSyn. Finally, using αSyn labelled with 7AFM‐M, we demonstrated that high density of αSyn on lipid membranes may lead to the partial membrane destruction with a formation of lipoprotein particles. A thiol‐reactive solvatochromic probe with two‐band emission was synthesized. It was applied for labelling amyloidogenic protein α‐synuclein, and was shown to discriminate at least three protein forms: unstructured, membrane‐bound and amyloid form. The presented approach may be used in the development of fluorescent sensors for protein interactions and transformations. [ABSTRACT FROM AUTHOR]

The formation of chromophore arrays using a DNA templating approach leads to the creation of supramolecular assemblies, where the optical properties of the overall system can be fine‐tuned to a large extent. In particular, porphyrin derivatives have been shown to be versatile building blocks; mostly covalent chemistry was used for embedding the units into DNA strands. Self‐assembly of porphyrin modified nucleosides, on the other hand, has not been investigated as a simplified approach. We report on the synthesis of a magnesium(II) tetraaza porphine (MgTAP) coupled to deoxyuridine, and array formation on DNA templates which contain well‐defined oligo(dA) segments showing strong fluorescence enhancement which is significantly larger than that with a Zn‐porphyrin. The use of the deep‐eutectic solvent glycholine is essential for successful assembly formation. The system allows for sizing of short tandem repeat markers with multiple adenosines, thus the concept could be adaptable to in vitro forensic DNA profiling with a suitable set of different chromophores on all nucleosides. [ABSTRACT FROM AUTHOR]

A series of fused 4,5‐borazaropyrrolo[1,2‐a]quinolines have been prepared from potassium organotrifluoroborates and substituted 1‐(2‐aminophenyl)pyrroles via direct formation of C–B and N–B bonds. The target products were obtained in moderate to high yields under mild conditions. The optical properties of some products were investigated by UV/Vis spectroscopy and spectrofluorometry. Moreover, the influence of structural modification on the spectroscopic and electronic properties was studied by DFT calculations. [ABSTRACT FROM AUTHOR]

The paper outlines a synthetic approach towards novel spacer‐extended bis‐ene‐yne structures via a tandem thiophene ring‐opening reaction to selectively obtain the Z,Z‐isomers. Various unsaturated spacer moieties are matter of interest in these investigations owing to potential applications in organic electronics. As a result, the successful application of the tandem ring‐opening process on a representative set of spacer‐extended substrates is demonstrated and the limitations regarding substrate and product scope are revealed in terms of ring‐opening ability and stability. Additionally, a general oxidation protocol for ene‐yne compounds capable of accessing double‐sided sulfone species is developed. The comparison of the photophysical and electronic properties before and after oxidation reveals significant effects of the chemical modification on the intrinsic characteristics of the materials and thus a wide variability of the developed molecular building blocks. [ABSTRACT FROM AUTHOR]

Herein work on 2,3‐substituted norbornadiene‐quadricyclane molecular photoswitches designed for solar energy storage purposes is presented. A series of six new systems bearing 1,4‐ or 1,5‐alkyl triazoles as the acceptor unit combined with various aryl donor groups, as well as four functional intermediates, were synthesized and fully characterized. The new photoswitches were evaluated by measuring optical absorption profiles, activation energies for the thermal conversion of quadricyclanes to norbornadienes, as well as the storage energy densities. These triazoles featured a molar energy storage of 81.2–101 kJ mol–1corresponding to energy densities of 215–267 kJ kg–1. The optical absorption profiles exhibited absorption onsets up to 382 nm and a study of the thermally activated conversion from high‐energy quadricyclanes to norbornadienes revealed energy storage half lives of up to 402 days at 25 °C. The modular nature of the “click chemistry” synthesis concept used herein enables access to a large range of compounds with tailored properties such as solubility, thermal half‐life, and solar spectrum match. [ABSTRACT FROM AUTHOR]

The conformational and stereodynamic properties of a pyrene‐substituted ethylthioporphyrazine (PzPy), promising as a dye for organic optoelectronic applications and light‐harvesting systems, have been investigated by DFT computations and variable‐temperature NMR and HPLC. In PzPy, rotation around the pyrene–macrocycle bond is hindered and the molecule displays atropisomerism, existing as a pair of enantiomers, thus representing the first chiral alkyl‐porphyrazine to be reported in the literature. The rotational barrier (ΔG‡ ≈ 22.0 kcal mol–1), measured by variable‐temperature HPLC experiments, allows chromatographic separation of the enantiomers on a chiral stationary phase below 0 °C, whereas racemization spontaneously occurs at room temperature. The absolute configurations of the eluted enantiomers were also determined by computational analysis of their electronic circular dichroism spectra. The influence of alkyl chain length and metal complexation on the molecular stereodynamic properties have also been investigated by studying its novel octylthio derivative (PzPy‐octyl) and PdII complex (PdPzPy), respectively. The latter also is the first example of a PdII–alkylthioporphyrazine complex. Given that PzPy has been used in the preparation of hybrid materials with nanocarbons for optoelectronic applications, the presence of an axial chirality element may play a key role in its interaction with semiconducting chiral nanotubes. [ABSTRACT FROM AUTHOR]

Conjugated organic polymers, small molecules, and transition metal organometallic complexes are used as active semiconducting materials in electronic and optoelectronic devices including organic solar cells (OSCs), organic field effect transistors (OFETS), organic light emitting diodes (OLEDs). While some of these technologies are mature and already available on the market, research is still very active in academic and industrial laboratories to gain better performances. Major drawbacks which still limit large industrial production of some of these devices are not only the non‐optimized performances, but also stability issues and cost. In fact, wide applicability of organic electronic technology largely relies on the development of efficient, durable and cost‐effective materials. Properties of molecular and polymeric semiconductors can be properly engineered and finely tuned by the design of the conjugated molecular structure and the selective introduction of various functional groups as substituents. Selective functionalization of the conjugated backbone with fluorine atoms and fluorinated substituents has been largely demonstrated to be an effective structural modification not only for tuning optoelectronic properties, but also to affect solid state organization and to improve stability. This review covers the most important classes of materials (conjugated polymers, small molecules, and organometallic complexes) reporting for each of these classes the applications in OSCs, OFETs, and OLEDs and highlighting the role of fluorine functionalization on the properties. The literature shows intriguing results that can be achieved by fluorine functionalization, and it also points out that this research field is still promising for future progress. [ABSTRACT FROM AUTHOR]

A series of 6,6′‐bis(O‐4‐arylethynylbenzoyl)‐α,α‐trehaloses (aryl groups; 1a: 1‐pyrenyl, 1b: 9‐anthryl, 1c: phenyl) were synthesized and fully characterized. Their photophysical properties were investigated by UV/Vis/fluorescence spectroscopy, and were rationalized by TDDFT calculations. Moreover, the emission maxima of 1a and 1b in THF/H2O considerably shifted to a longer wavelength region with increasing H2O fraction owing to the formation of excimers. The pyrenyl derivative 1a was efficiently taken into HeLa CD4+ human cervical cancer cells and emitted bright green fluorescence. [ABSTRACT FROM AUTHOR]

We present first principle studies on the rational design of an acridine/N‐methylacridinium dye (Acr/MeAcr+) substituted terpyridine ligand to investigate if these chromophores can act as triplet‐energy storage units in bis(terpyridine) ruthenium(II) complexes. We studied the influence of the dye form (Acr/MeAcr+) as well as the interconnecting linker unit (none, 4‐phenyl, or 5‐thien‐2‐yl) and investigated these aspects by steady‐state/time‐resolved spectroscopy, cyclic voltammetry, X‐ray structure analysis, and DFT calculations. [ABSTRACT FROM AUTHOR]

In this study, we report on the synthesis of new organic fluorophores containing either the benzo[1,2‐d:4,5‐d′]bisthiazole or the dithieno[3,2‐b:2′,3′‐d]silole heterocyclic unit, and on their application for the fabrication of luminescent solar concentrators (LSCs) made of poly(methyl methacrylate) (PMMA) thin films. In solution, the new compounds absorbed light in the visible region and displayed a brilliant green emission in the 500–600 nm range with moderate‐to‐good fluorescence quantum yields (0.25–0.68). Dispersions of selected fluorophores in PMMA thin films mostly maintained the light absorption features observed in solution, although in the case of benzobisthiazole‐based fluorophore 1a an evident fluorescence red‐shift was observed when increasing the compound concentration in the film. In agreement with its promising optical properties, LSCs prepared with the latter compound yielded interesting optical efficiencies up to 6.42 %, not far from those of state‐of‐the‐art PMMA LSC devices. [ABSTRACT FROM AUTHOR]

The design of a novel concept for the synthesis of [3:2] pentakis‐adducts of fullerene C60 is presented. A sequential tether‐directed, remote functionalization approach is introduced for the construction of the pentakis‐adducts. This fullerene derivative embellished with two different addends in two different directions can be considered as a valuable tecton for further functionalization. The stepwise cyclopropanation of C60 with a macrocyclic tris‐malonate and a bis(β‐keto ester) yielded the corresponding pentakis‐adduct with an incomplete octahedral addition pattern. This reaction sequence gave access to two pairs of enantiomers that were easily separated by column chromatography on an achiral stationary phase and subsequently characterized. [ABSTRACT FROM AUTHOR]

Donor–π–acceptor (D–π–A) molecules play an important role in various fields including polymer solar cells (PSCs) and dye‐sensitized solar cells (DSSCs). In PSCs, naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole (NTz) has emerged as a promising acceptor owing to its higher electron‐accepting ability compared with 2,1,3‐benzothiadiazole (BT), which is a widely used acceptor unit in DSSCs as well as PSCs. On the other hand, various D–π–A‐type porphyrin dyes have been developed for use in DSSCs and have achieved high power conversion efficiencies (η). Given that enhanced D–π–A character improves light‐harvesting ability in the near‐infrared (NIR) region, we have designed and synthesized for the first time a novel D–π–A‐type porphyrin sensitizer, ZnPNTz, incorporating the NTz unit. The porphyrin ZnPNTz shows excellent absorption in the NIR region together with a large Stokes shift as a result of the NTz moiety. A DSSC fabricated with ZnPNTz exhibits photocurrent generation at wavelengths up to 860 nm. Therefore, we have demonstrated that the NTz unit is a promising electron‐acceptor unit for novel D–π–A small molecules exhibiting unique optical properties in the NIR region. [ABSTRACT FROM AUTHOR]

A concise organolithium‐free route to build electron‐accepting molecules consisting of two 2‐(11‐oxoanthra[1,2‐b]thiophen‐6‐ylidene)propanedinitrile units connected by functionalized π‐conjugated linkers was developed. Annulation of two thiophene rings in one step was achieved through chemoselective cyclocondensation of a bis(ethynylanthraquinone) substrate with sodium sulfide. Finally, electron‐accepting dicyanomethylene moieties were introduced by Knoevenagel condensation with malodinitrile. The synthesized 2,2′‐[2,2′‐arenediylbis(11‐oxoanthra[1,2‐b]thiophene‐6‐ylidene)]dipropanedinitriles were studied by UV/Vis and fluorescence spectroscopy, cyclic voltammetry, and DFT calculations. The acceptor properties of these compounds were confirmed by efficient light‐induced electron transfer in their blend with a donor polymer, poly(3‐hexylthiophene‐2,5‐diyl), detected by electron paramagnetic resonance spectroscopy. [ABSTRACT FROM AUTHOR]

Porphyrin–trimethyl‐β‐cyclodextrin (TMe‐β‐CDx) complexes have pseudorotaxane structures in which two meso‐phenyl and/or ‐pyridyl moieties penetrate the upper rim of two TMe‐β‐CDx molecules. Porphyrin derivatives with one to three pyridyl moieties at meso positions formed complexes with TMe‐β‐CDx in which the penetration of the upper rim of the two TMe‐β‐CDxs by the pyridyl moieties was minimized. In contrast, in TMe‐β‐CDx complexes formed with porphyrin derivatives bearing two 2‐methoxyphenyl moieties and two pyridyl moieties, the pyridyl moieties penetrate the upper rim of the two molecules because steric hindrance prevents penetration by the 2‐methoxyphenyl moieties. [ABSTRACT FROM AUTHOR]

In a previous study we synthesized a series of bis-ocarborane- modified acenes and revealed various unique luminescence properties, such as highly efficient solid-state emission and luminochromism. Here we report further enhancement of the luminescence efficiencies of bis-o-carborane-modified acenes by thermally induced structural rearrangement from ortho- to meta-carborane. We found that the thermal rearrangement of the anthracene derivative 1 occurred close to the melting point and gave luminescent products. From a detailed investigation of the product obtained from 1, the transformation of the molecular structure was proven by X-ray crystallography. In addition, the analytical data indicated that rearrangement caused by heating at 300 °C occurred at only one of the two ocarborane units. In accord with the results of theoretical investigations of the transition states of 1 by quantum chemical calculations, we propose that the thermal rearrangement could proceed because of a low activation energy in the first rearrangement step due to the presence of the anthracene. On the basis of optical measurements, enhancements of not only luminescence efficiencies but also aggregation-induced emission were observed. Furthermore, we have demonstrated that this strategy for enhancing emission properties is applicable ot the corresponding tetracene derivative, resulting in a deep-red luminescent dye. [ABSTRACT FROM AUTHOR]

Novel luminescent organogelators based on nucleoside functionalized with carbazole (UC8, UC12 and UC16) were designed and synthesized. Their gelation ability was tested and it was found that both UC12 and UC16 could form stable organogels in toluene/petroleum ether. The UV-vis absorption, fluorescence emission and IR spectral changes during the gelation of UC12 proved that the self-assembly was driven by H- bonding. The morphology of the xerogel UC16 obtained from toluene/petroleum ether (v/v = 1/1) displayed tough rod-like microstructures, and 3D networks formed from lots of nanofibers were observed for the xerogel UC16 obtained from toluene/petroleum ether (v/v = 2/1). It was interesting that the obtained organogels emitting blue light could be destroyed by the addition of F-, accompanied with the declining the emission intensity. Therefore, these organogels could be used as sensory materials to recognize F-. [ABSTRACT FROM AUTHOR]

A star‐shaped molecule with a central electron‐deficient triazine ring connected to three electron‐rich N‐annulated perylene tetraesters was synthesized. Its application as an emissive layer in the fabrication of a sole and host–guest solution processable OLED, exhibiting bright green emission with good electroluminescence efficiency is demonstrated. [ABSTRACT FROM AUTHOR]

A novel method for the synthesis of a thiophene analogue of isoindigo (TIIG) is described. The reaction involves a palladium-catalyzed C-H activation/oxidative cyclization sequence. This new methodology has potential for diversifying the isoindigo family. The thin-film transistors (TFTs) prepared from a TIIG-based copolymer (PIDTT-TIIG) with indacenodithieno[3,2-b]thiophene (IDTT) exhibit unipolar charge-transport properties with hole mobilities of 0.17 cm² V-1 s-1. [ABSTRACT FROM AUTHOR]

New π-extended triazacoronene derivatives containing three peri-benzopyrano extensions were successfully synthesized through tandem triflic acid catalyzed threefold Pictet- Spengler cyclization and K2CO3-catalyzed ipso-aromatic substitution in one pot. The structure was verified by X-ray diffraction analysis and was found to form a sandwich-type π trimer in the crystalline state. The π-extended triazacoronenes showed reasonable solubility, high thermal stability, and remarkably repeatable electroluminescent emissions. [ABSTRACT FROM AUTHOR]

We have discovered a new and unexpected substitution reaction of BODIPY. Through single-crystal XRD analysis, DFT calculations, and other complimentary spectroscopic methods, we have confirmed that the molecular structural assignment of the previously reported nucleophilic substitution of the halogenated carbon atom at the meso position of BODIPY was inaccurate. Indeed, in these substitution reactions, the amino attaches to the methyl group at the 3- or 5-position and not on the meso-carbon of the BODIPY core. As a result of this unexpected substitution reaction, we prepared a BODIPY dimer, attached to the stable radical TEMPO (2,2,6,6-tetramethyl-1- piperidinyloxyl). We confirmed the efficient formation of the triplet state (ΦΔ = 59%, τT = 2.8 μs) of this BODIPY-TEMPO triad through the radical-enhanced intersystem crossing mechanism by using nanosecond time-resolved transient absorption spectroscopy. Through time-resolved EPR spectroscopy, the doublet (spin angular momentum quantum number S = 1/2) and quartet (S = 3/2) states of the triad were observed. Moreover, we observed a strong intramolecular ground-state interaction between the BODIPY chromophores in the triad, which shows new spectral features different to those of H- or J-aggregates and the exciton coupling effect. These TEMPO-labeled compounds were used as triplet photosensitizers for triplet- triplet annihilation (TTA) upconversion (quantum yield ΦUC = 4.7%). [ABSTRACT FROM AUTHOR]

Polycyclic heteroaromatic compounds are potentially interesting materials for organic electronic applications. While most of those compounds contain nitrogen or sulfur, oxygen-based structures are much rarer, especially those including annulated pyrane rings. By the utilization of a cascade of Pictet--Spengler reactions and thermally induced ipso-substitutions, a series of peri-benzopyrano-fused nitrogen containing polycyclic aromatic compounds was synthesized and their optoelectronic properties investigated by UV/Vis and emission spectroscopy as well as cyclic voltammetry and DFT-calculations. [ABSTRACT FROM AUTHOR]

Rylenes are peri-fused naphthalene oligomers and possess a unique electronic structure, which makes them attractive materials as organic dyes and semiconductors. In particular, rylenes beyond terrylene are promising near-infrared dyes with high molar extinction coefficients. Recent studies have demonstrated an unusual open-shell diradical character for long rylene molecules and potential half-metallic properties of polyrylene ribbon. However, the synthesis of long rylenes and polyrylene is a very challenging task, with various strategies directed towards solving the critical molecular aggregation and stability problems having been developed since 1910. In addition, recent research has also shown that quinoidal rylenes have an irresistible tendency to become diradical, and so they constitute a new type of open-shell singlet diradicaloids with magnetic activity. This microreview mainly summarizes the synthesis of long rylene ribbons and quinoidal rylene diradicaloids, together with their unique electronic structures and physical properties. [ABSTRACT FROM AUTHOR]

Anthracenyl boronic acid derivatives are used for the first time as hydrogen-bond and π-donors to obtain a series of novel 1:1 mixed stacked π-organic materials with interesting structural, UV/Vis reflectance and emission properties by reaction with quinones in both solution and the solid. The underlying principles, which have led to hetero-assembly, could be applied to construct a potentially large variety of mixed stacked π-organic solid-state materials for technological applications. [ABSTRACT FROM AUTHOR]

New organic materials containing a cyano-functionalized carbazole moiety at one end linked to different chromophores such as fluorene, carbazole, and triphenylamine at the other end through an acetylene spacer are synthesized and characterized by photophysical, electrochemical, thermal, and electroluminescence studies. A meta-like linkage at the C-2 and C-7 atoms of the central carbazole moiety and the choice of chromophore restricted the emission to the near-ultraviolet region. The photophysical properties of the compounds depend on the nature of the chromophore attached to the carbazole unit. A triphenylamine-substituted derivative exhibited the longest wavelength emission in the series, attributable to the elongated conjugation and electron richness of triphenylamine, whereas the phenyl- and fluorene-functionalized molecules showed the shortest wavelength emissions with vibronic patterns. The compounds containing carbazole and triphenylamine units exhibited positive solvatochromism in their fluorescence spectra, and this behavior is characteristic of charge transfer from a donor to an acceptor. A fluorene derivative containing cyano substituents at the carbazole and fluorene moieties exhibited the best electroluminescence characteristics in the series, probably because of balanced charge transport and effective confinement of the excitons in the emissive layer. [ABSTRACT FROM AUTHOR]

A series of functionalized triptycene scaffolds has been synthesized using 2-formyltriptycene and 5-(2-triptycenyl)dipyrromethane. Using these two key precursors, mixed condensations with different aromatic aldehydes and aryl-dipyrromethanes gave access to all members of triptycenyl meso-substituted porphyrins (AB3-, A2B2-, A3B-, and A4) and allowed their photophysical and electrochemical characterization. Additionally, the first crystal structure of tetratriptycenylporphyrin is reported. 2-Formyltriptycene was also used for the preparation of two different mono-BODIPY-triptycene compounds, while 2,6,14-triiodotriptycene was used in Suzuki and Sonogashira cross-coupling reactions to obtain threefold BODIPY-substituted triptycene-dye conjugates. The mono- and tri-BODIPY-substituted triptycene scaffolds exhibit good absorption in the visible to NIR region indicating the potential use of the triptycene scaffold as the core of multi-dye light-harvesting systems. [ABSTRACT FROM AUTHOR]