Bisimide Derivatives Research Articles

Hierarchical Coaggregation of Perovskite Nanocrystals and Dye Supramolecular Aggregates into a High‐Order Heterostructure

AbstractA high‐order heterogeneous nanostructure (heterostructure) composed of semiconductor nanocrystals (NCs) and organic dye supramolecular aggregates can exhibit distinctive photophysical properties arising from the interaction between them and can activate multicomponent materials chemistry. Herein, the study demonstrates a hierarchical coaggregation pathway guiding a high‐order heterostructure composed of a cubic‐shaped perovskite NC and perylene bisimide derivative (PBI) aggregates. The final morphologies in their coaggregation are determined by the aggregation levels of PBI before mixing with NCs. While mixing of NCs with monomers or aged fibrous aggregates of PBI results in the formation of low‐order or phase‐separated coaggregates, respectively, a coaggregation of the NC with unaged sheet‐like aggregates of PBI afforded the high‐order heterostructure. In this heterostructure, one‐dimensionally arranged NC and aggregated PBI are alternately connected at several nanometer‐scale intervals, like Roman pavement. Moreover, photoluminescence spectra and time‐resolved measurements at single coaggregate levels indicate that the high‐order heterostructure exhibited more efficient fluorescence resonance energy transfer from the NC to PBI aggregates compared to the phase‐separated coaggregates.

Relaxation dynamics of higher excited states of perylene-substituted perylene bisimide derivatives.

Stepwise two-photon absorption processes have received considerable attention, especially in photocatalysis, due to their relatively lower power threshold, characteristic spatial selectivity, amplification of chemical reactions, and so on. Meanwhile, studies on the relaxation dynamics of higher excited states in condensed systems have been limited for several molecular systems due to the short-lived nature of these states. In this study, we synthesized perylene-substituted perylene bisimide (PBI) and its derivate as model compounds and investigated their excited-state dynamics, including higher excited states, using pump-repump-probe spectroscopy. We revealed that these molecules form charge-transfer (CT) states instantaneously after the excitation, regardless of whether it is the perylene moiety or the PBI moiety that is excited. The lifetime of the CT state was shorter when the distance between the donor (perylene) and the acceptor (PBI) was shorter. Moreover, we also revealed that a higher-lying CT state generated by the stepwise excitation of the CT state using a 740-nm pulse induced Stark effect to the neighboring perylene moiety. The Stark effect not only gives more detailed information about the CT state, but also presents the possibility of new photofunctions, such as instantaneous modulation of the electronic state to achieve optimal electronic properties. These insights contribute to understanding advanced photochemical reactions and would be important for exploring photocatalytic reactions involving higher excited states.

Carrier transport and mesomorphic properties of deformable fluorinated perylene bisimide bearing disiloxane chains

Carrier transport and mesomorphic properties of deformable fluorinated perylene bisimide bearing disiloxane chains

End-to-End Bent Perylene Bisimide Cyclophanes by Double Sulfur Extrusion.

Bending inherently planar π-cores consisting of only six-membered rings has traditionally been challenging because a powerful transformation is required to compensate for the significant strain energy associated with bending. Herein, we demonstrate that sulfur extrusion can achieve substantial molecular bending of a perylene structure to form a substructure of a Vögtle belt, a proposed yet hitherto elusive carbon nanotube fragment. Bent perylene bisimide (PBI) derivatives were synthesized through a double-sulfur-extrusion reaction from the corresponding sulfur-containing V-shaped precursors with an internal alkyl tether. The effect of bending the inherently planar PBI core, which is a recent topic of interest for the design of advanced organic electronic and optoelectronic materials, was investigated systematically. Increasing the curvature leads to a red shift in the absorption and emission spectra, while the fluorescence quantum yields remain high. This stands in contrast with the nonemissive features of previously reported nonplanar PBI derivatives based on conjugative tethers. Detailed photophysical measurements indicated that the increasing curvature with shorter alkyl tethers (i) slightly facilitates intersystem crossing and (ii) significantly suppresses the internal conversion in the excited state of the present bent PBI derivatives. The latter characteristics originate from the restricted dynamic motion associated with the charge-transfer (CT) character between the core chromophores and the N-aryl units.

Self-Assembly Behavior of Perylene Bisimide Derivatives on a Perovskite Nanocrystal Surface

Self-Assembly Behavior of Perylene Bisimide Derivatives on a Perovskite Nanocrystal Surface

Beyond Molecular Recognition: A Perylene Bisimide Derivative as a Functional Mimic of Chlorpyrifos.

Supramolecular assemblies of perylene bisimide derivative (PBI-SAH) have been developed which show 'turn-on' detection of chlorpyrifos in aqueous media, apple residue and blood serum. Differently from the already reported fluorescent probes for the detection of CPF, PBI-SAH assemblies also show affinity for acetylcholinesterase (AChE) which endow the PBI-SAH molecules with mixed inhibitory potential to restrict the AChE catalysed hydrolysis of acetylthiocholine (ATCh) in MG-63 cell lines (in vitro) and in mice (in vivo). The molecular docking studies support the inhibitory activity of PBI-SAH assemblies and their potential to act as safe insecticide with high benefit to harm ratio. The insecticidal potential of PBI-SAH derivative has been examined against Spodoptera litura (S. litura) and these studies demonstrate its excellent insecticidal activity (100 % mortality in nineteen days). To the best of our knowledge, this is the first report regarding development of PBI-SAH assemblies which not only detect chlorpyrifos but also mimic AChE inhibitory activity of CPF to show promising aptitude as safe insecticide.

Enantiopure J-Aggregate of Quaterrylene Bisimides for Strong Chiroptical NIR-Response.

Chiral polycyclic aromatic hydrocarbons can be tailored for next-generation photonic materials by carefully designing their molecular as well as supramolecular architectures. Hence, excitonic coupling can boost the chiroptical response in extended aggregates but is still challenging to achieve by pure self-assembly. Whereas most reports on these potential materials cover the UV and visible spectral range, systems in the near infrared (NIR) are underdeveloped. We report a new quaterrylene bisimide derivative with a conformationally stable twisted π-backbone enabled by the sterical congestion of a fourfold bay-arylation. Rendering the π-subplanes accessible by small imide substituents allows for a slip-stacked chiral arrangement by kinetic self-assembly in low polarity solvents. The well dispersed solid-state aggregate reveals a sharp optical signature of strong J-type excitonic coupling in both absorption (897 nm) and emission (912 nm) far in the NIR region and reaches absorption dissymmetry factors up to 1.1 × 10-2. The structural elucidation was achieved by atomic force microscopy and single-crystal X-ray analysis which we combined to derive a structural model of a fourfold stranded enantiopure superhelix. We could deduce that the role of phenyl substituents is not only granting stable axial chirality but also guiding the chromophore into a chiral supramolecular arrangement needed for strong excitonic chirality.

High Electrochromic Performance of Perylene Bisimide/ZnO Hybrid Films: An Efficient, Energy-Saving, and Green Route.

The composite or hybrid of organic and inorganic materials is one of the common ways to improve the properties of photoelectric functional materials. Perylene bisimide (PBI) derivatives, as large π-conjugated organic small molecules, are a class of photoelectric functional materials with excellent performance. However, there were few reports on PBIs in the electrochromic field due to the difficulty of film-forming caused by their generally poor solubility. Here, water-soluble PBI derivatives (PDI-COOH and PCl-COOH) were synthesized. The hybrid films (ZnO@PDI-COOH/PCl-COOH) formed by the coordination bond and π-π stacking were prepared via a simple solution immersion method. Fourier transform infrared spectrometry and X-ray diffraction as well as scanning electron microscopy, and energy-dispersive spectrometry results further confirmed the formation of hybrid films. At the same time, electrochemical and spectroelectrochemical analyses revealed that the films have reversible redox activity and cathodic electrochromic properties, which can change from orange-red to purple. The ZnO@PDI-COOH hybrid film formed by coordination bonds exhibits fast switching times (1.7 s colored time and 2.6 s bleached time), good stability (retain 92.41% contrast after 2400 cycles), a low driving voltage (-0.6-0 V), and a high coloration efficiency (276.14 cm2/C). The corresponding electrochromic devices also have good electrochromic properties. On this basis, a large-area (100 mm × 100 mm) electrochromic display device with fine patterning was fabricated by using the hybrid film, and the device shows excellent reversible electrochromic performance. This idea of constructing organic-inorganic hybrid materials with coordination bonds provides an effective, energy-saving, and green method, which is expected to promote the large-scale and fine production of electrochromic materials.

Intersystem crossing of perylene bisimide neutral, radical anion, and dianion derivatives compared via ultrafast spectroelectrochemistry.

Perylene bisimides are widely studied due to their various applications. Most research is carried out on neutral molecules but charged species are essential in the context of organic electronics and photovoltaics. In this study, we carry out ultrafast transient absorption spectroelectrochemistry and coherent two-dimensional electronic spectroelectrochemistry on three different neutral perylene bisimide derivatives as well as their singly and doubly reduced species. We compare an unsubstituted, flat parent perylene bisimide with two twisted ones that introduce spin-orbit coupling, leading to enhanced intersystem crossing. The internal conversion from higher excited states to the lowest electronically excited state occurs in the picosecond regime with lifetimes significantly shorter for the charged species compared to the neutral ones. Coherent oscillations of the transients for the flat dianion of parent perylene bisimide indicate the occurrence of Fermi resonance. The corresponding vibrational coupling and the superposition of the participating vibrational modes may lead to an enhanced charge separation and triplet formation.

Automated Supramolecular Polymerization in a Microflow: A Versatile Platform for Multistep Supramolecular Reactions.

This work reports a basic microflow system capable of performing multistep supramolecular polymerization. In this system, injection of the monomer, directional supramolecular copolymerization, removal of the unreacted monomer, and purification of the product supramolecular diblock copolymers are realized along a three-stream flow. When injecting a supramolecular polymer into the central stream of the three-stream flow, the supramolecular polymerization always occurs in the central flow, with the two lateral flows serving as supply and removal lines for the monomer. Employing two kinds of perylene bisimide derivatives as monomers, we confirmed that the reaction occurred selectively at the forward-facing terminus of the supramolecular polymer, along with recovery of the unreacted monomer, ultimately leading to a high-purity supramolecular diblock copolymer. Diblock copolymers are basic units for preparing multicomponent supramolecular block copolymers. Thus, connecting the present system in series would, in principle, result in a "microplant" capable of producing supramolecular polymers having desired inner complexity.

A high-performance formaldehyde luminescent tubular sensor enabled by a cyclometalated alkynyl-gold(III) complex-contained perylene bisimide derivative

Fast, sensitive, selective, and reliable detection of formaldehyde (FA) in the air on-site and at real-time remains a challenge for years. Herein, we report a totally new miniaturized FA luminescent tubular sensor, which depicted an experimental detection limit lower than 0.01 mg/m 3 , a response time less than 5 s, and a recovery time less than 20 s. Moreover, daily necessaries showed no observable interference to the detection, and no decay in the sensor’s performance was found after 130-cycle successive detections. The superior sensing performance of the sensor as developed was mainly ascribed to the application of a new sensing luminophore (Au-PBI), which is a chemical combination of a perylene bisimide derivative (Ref-PBI) with a cyclometalated alkynyl-gold(III) complex. Unlike Ref-PBI, Au-PBI is highly luminescent in solid state, enabling the film to show response to FA in a luminescence quenching way. Importantly, convenient detection of indoor FA was achieved via utilization of the tubular sensor as developed. • Innovative design of a non-planar perylene bisimide derivative (Au-PBI) enables fabrication of a film-based luminescent sensor. • Sensitive, selective, on-site and at real-time detection of formaldehyde was realized with the sensor. • Almost interference free, 5 s response and 0.01 mg/m 3 detection limit were realized. • Real indoor scene detection of formaldehyde was successfully performed.

Yellow Light-Emitting Highly Soluble Perylene Bisimide Dyes by Acetalization of Bay-Hydroxy Groups.

A new class of perylene bisimide (PBI) derivatives is introduced by bridging 1,12- and 1,6,7,12-hydroxy functionalized bay positions with oxygen-carbon-oxygen linker(s). This functionalization rigidifies the inherently twisted bay-substituted perylene core to afford dyes of high stability and solubility that are characterized by vibronically well-resolved absorption and fluorescence spectra and intense yellow emission with quantum yields close to 100%.

Effect of mixed Frenkel and charge transfer states in time-gated fluorescence spectra of perylene bisimides H-aggregates: Hierarchical equations of motion approach.

We theoretically investigated the effect of mixed Frenkel (F) and charge transfer (CT) states on the spectral properties of perylene bisimide (PBI) derivatives, focusing on the role of strong electron-phonon interactions. The model consists of a four-level system described by the Holstein Hamiltonian coupled to independent local heat-baths on each site, described by Brownian spectral distribution functions. We employ the reduced hierarchical equations of motion (HEOM) approach to calculate the time evolution of the system and compare it to the pure F exciton cases. We compute the absorption and time-gated fluorescence (TGF) spectra for different exciton transfer integrals and F-CT bandgap conditions. The coherence length of excitons (Ncoh) is evaluated employing two different definitions. We observe the presence of an excited hot state peak whose intensity is associated with the delocalization of the excited species and ultrafast dynamics that are solely dependent on the frequency of the local bath. The results indicate that the inclusion of CT states promotes localization of the excitons, which is manifested in a decrease in the intensity of the hot state peak and the 0-1 peak and an increase in the intensity of the 0-0 emission peak in the TGF spectrum, leading to a decrease of Ncoh.

Rigid Bay-Conjugated Perylene Bisimide Rotors: Solvent-Induced Excited-State Symmetry Breaking and Resonance-Enhanced Two-Photon Absorption

Intramolecular charge transfer and excited-state symmetry breaking have a significant effect on the nonlinear optical properties of multipolar chromophores. Rigid and nonplanar perylene bisimide derivatives (PBIs) functionalized at bay positions were comparatively and comprehensively investigated. In apolar solvents, two quadrupolar molecular rotors showed an obvious decrease of the A0-0/A0-1 ratios, suggesting strong exciton coupling with the adjacent PBI units initiated by the π-π stacking. The vanishment of the preferable dimer emission in polar solvents supported the plausible phenomena of excited-state symmetry breaking, thanks to the facile rotation around the rigid linkers. Comparative femtosecond transition absorption studies confirmed their notable differences in relaxation dynamics and the generation of radical anions (PBI•-) and cations (PBI•+). The maxima two-photon absorption (2PA) wavelengths obtained for the molecular rotors were slightly red-shifted to 670 nm with intrinsic resonance-enhanced characteristics, reflecting the synergistic effect of functional positions and molecular architectures. Meanwhile, the obvious increase of significant 2PA cross-section values in polar solvents illustrated the stabilization of the symmetry-broken dipolar states. Further femtosecond Z-scan also manifested the contribution of excited-state dynamics on the nonlinear optical properties of multipolar chromophores.

Nanomechanical behavior of hierarchical self‐assemblies of perylene bisimide derivatives

AbstractIn the field of self‐assemblies of perylene bisimide (PBI) derivatives, effect of molecular structure on the mechanical properties of assemblies is essential but still not understood in full detail. To reveal the relationships of PBI molecules and mechanical properties of their assemblies, the PeakForce Quantitative Nanomechanical Mapping (PeakForce QNM) is applied to visualize the structures and quantify the mechanical properties of assemblies formed by the model PBI derivatives (M1: C6H13‐PBI‐OH; M2: C12H25‐PBI‐OH). The influence of the linear alkyl chainson self‐assembly of PBI derivatives has been investigated. We found that the long‐range ordered structures could be formed for both M1 and M2 in high‐polarity solvents. M1 formed the micron‐size bricks with the Young's modulus of (3.1 ± 1.0) GPa, whereas M2 assembled into the nanosheets with the Young's modulus of (2.5 ± 0.5) GPa. The competitive, non‐competitive and cooperative interactions of the π–π stacking, hydrogen‐bond interactions, and van der Waals interactions facilitated the growth of assemblies with the different hardness and size. This method can be used to investigate the molecular self‐assembly, which helps to establish relationships among structure, performance, and corresponding application of assemblies.

A Configurationally Tunable Perylene Bisimide Derivative‐based Fluorescent Film Sensor for the Reliable Detection of Volatile Basic Nitrogen towards Fish Freshness Evaluation

Comprehensive SummaryRapid and real‐time monitoring of food quality plays critical roles in the food industry and for the general public health. Herein, we specially synthesized a new perylene bisimide (PBI) derivative (PCB‐EpE) composed of two PBI units and a rigid o‐carborane linker, which was further employed in constructing a conceptual fluorescent film sensor for evaluating fish freshness. Photophysical studies indicate that PCB‐EpE displays an open “Z‐type” molecular configuration in chloroform and a closed “Δ‐type” configuration in methyl cyclohexane. Comparatively, “Z‐type” molecular configuration possesses higher fluorescence quantum yield and is more sensitive toward volatile basic nitrogen (VBN). It is noteworthy that the film sensor responds in less than 1 s even in ambient humidity condition. High correlation between the content of total volatile basic nitrogen (TVB‐N) in evaluating fish freshness with different storage time and the fluorescence response is achieved. Detection limit of the film sensor toward trimethylamine as an example is lower than 2.6 mg/m3. Comprehensive sensing investigations demonstrate the rapid detection, strong anti‐interference capability and excellent reusability of the film sensor toward testing VBN. To our knowledge, this is the first report to accurately predict TVB‐N value for the evaluation of fish freshness using a fluorescent film sensor, showing great potential for real‐life applications.

Density Functional Theory Investigation of the Doping Effects of Bromine and Fluorine on the Electronic and Optical Properties of Neutral and Ionic Perylene

Perylene and its derivatives are some of the promising organic semiconductors. They have found vast applications in many areas such as photovoltaic systems, organic light-emitting diodes, and so on. The instability of organic molecules under ambient conditions is one factor deterring the commercialization of organic semiconductor devices. Currently, most of the investigation of Perylene and its derivatives concentrated on its diimide and bisimide derivatives. In this work, an investigation of the effects of doping Bromine and Fluorine on the electronic and non-linear optical properties was carried out based on Density Functional Theory (DFT) as implemented in the Gaussian 09 software package. We computed the Molecular geometries of the molecules, HOMO-LUMO energy gap, global chemical indices and non-linear optical properties using the same method. The bond lengths and angles of the mono-halogenated molecules at different charge states were found to be less than that of the isolated Perylene. 1-fluoroperylene was found to be the most stable amongst the studied molecule for having the least bond angles and bond lengths. In the calculation of the energy bandgap neutral 1-fluoroperylene was observed to have the highest energy gap 3.0414 eV and 3.0507 eV for 6-31++G(d,p) and 6-311++G(d,p) basis sets respectively. These results were found to agree with the existing literature. This reconfirmed 1-fluoroperylene as the most stable molecule. The computations of the ionic molecules reported small values of the energy gap. The molecule with the most chemical hardness was obtained to be the neutral 1-fluoroperylene with a chemical hardness of 1.5253eV. All the ionic molecules results were found to be more reactive than their neutral form for having lower values of chemical hardness. For NLO calculations, the results showed an increment in their values with the ionic hybrid molecules having the largest values. In the case of first-order hyper-polarizability, 1-bromoperylene (neutral), 1-fluoroperylene (neutral), 1-bromoperylene (anionic), 1-fluoroperylene (anionic), 1-bromoperylene (cationic) and 1-fluoroperylene (cationic) were found to be 73.93%, 1.71%, 83.9%, 39.2%,38.7% and 41.7% larger than that of Urea respectively. These calculated results make these hybrid molecules suitable for a wide range of optoelectronic applications.

Multifunctional Shape Memory Films for a Flexible Electrical Sensor

AbstractShape memory polymers exhibit great potential for applications in aeronautics, astronautics, biomedicine, intelligent robots, and electronics. Based on traditional fabrication methods, as‐prepared shape memory micro‐/nanodevices are brittle with poor deformability. For instance, these devices shatter or crack when they are bent, which greatly limit their practical applications. In particular, there has been little use of shape memory films for high performance sensing devices in electrical circuits. Here, a novel polyvinyl alcohol (PVA) film is fabricated from a mixture of graphene nanosheets (GNs), sisal cellulose microcrystals (CNC), polyamine‐functionalized perylene bisimide derivative (APBI), and PVA through a simple electrospinning technique. These novel PVA films exhibit excellent thermal, mechanical, and shape memory properties. Moreover, after spin‐coating with Ag nanowires, the PVA films show excellent conductivity and flexibility in shape memory recovery cycles, and are used as a flexible sensing device in the circuit.

Resonance-Enhanced Two-Photon Absorption and Optical Power Limiting Properties of Three-Dimensional Perylene Bisimide Derivatives.

Push-pull organic structures characterized by an intramolecular charge transfer (ICT) process and π-electron delocalization are potentially interesting luminescent materials. A series of three-dimensional o-carborane-containing perylene bisimide derivatives (PBIs) were synthesized, and their optical properties were systematically investigated to illustrate the stereo effect, especially on the two-photon absorption (2PA) and optical power limiting (OPL) properties. Open-aperture Z-scan curves showed that all four PBIs displayed strong and broad two-photon absorptivities based on the resonance-enhanced phenomenon. The maximum degenerate two-photon absorption cross section (δ2PA) increased with the number of PBI substituents. The derivative CB-PBI possessed a δ2PA value of ∼2400 GM at 650 nm, a significant enhancement in comparison with that of the parent PBI (∼719 GM), ascribed to the present stereo effect. When the aromatic-donating units changed from naphthyl and pyrenyl to PBI, the generated multidimensional intramolecular charge transfer (ICT) from the aromatic units to the o-carborane cage contributed to the 2PA processes. All of the fluorophores exhibited excellent optical power limiting (OPL) performances as well as a minimum limiting threshold of ∼4.98 mJ/cm2 for CB-PBI. These significant results not only allow us to get deep insight into the nature of the fundamental stereo effect and nonlinear optical (NLO) response involved but also guide us toward the design of new multifunctional luminescent materials.

Localized and Surface Plasmons Coupling for Ultrasensitive Dopamine Detection by means of SPR‐Based Perylene Bisimide/Au Nanostructures Thin Film

AbstractDopamine (DA) is an important catecholamine neurotransmitter involved in neural and hormonal functions. Neural diseases, as Parkinson's, are connected to a significant lowering of DA concentration to picomolar levels in cerebrospinal fluid. So, in this contribution, a hybrid active layer based on a perylene bisimide (PBI) derivative and multishaped Au nanostructures is proposed for the development of surface plasmon resonance (SPR) dopamine detection system. PBI molecules, transferred as thin film by the dip coating approach, are demonstrated to be able to detect dopamine down to 10–12 m by SPR method. The presence of Au nanostructures promotes an important surface enhanced Raman scattering effect of Raman PBI signals highlighting a strong energetic communication between the two species. In this way, when PBI/Au nanostructures (AuNS) films are deposited by the layer‐by‐layer method and used for DA SPR detection, the sensitivity toward dopamine 10−12 m is doubled. The PBI/AuNS hybrid layer is able to detect picomolar concentration of dopamine, due to the coupling of localized (AuNS) and propagating surface plasmons on SPR slide. In particular, an interfacial coupling among localized surface plasmon resonance on AuNS and the propagating plasmon on Au thin film (of SPR slide) can be promoted.