Intramolecular Noncovalent Interactions Research Articles

Over 18% Efficiency Ternary Organic Solar Cells with 300nm Thick Active Layer Enabled by an Oligomeric Acceptor.

The development of high-efficiency thickness-insensitive organic solar cells (OSCs) is crucially important for the mass production of solar panels. However, increasing the active layer thickness usually induces a substantial loss in efficiency. Herein, a ternary strategy in which an oligomer DY-TF is incorporated into PM6:L8-BO system as a guest component is adopted to break this dilemma. The S···F intramolecular noncovalent interactions in the backbone endow DY-TF with a high planarity. Upon the addition of DY-TF, the crystallinity of the blend is effectively improved, leading to increased charge carrier mobility, which is highly desirable in the fabrication of thick-film devices. As a result, thin-film PM6:L8-BO:DY-TF-based device (110nm) shows a power conversion efficiency (PCE) of 19.13%. Impressively, when the active layer thickness increases to 300nm, an efficiency of 18.23% (certified as 17.8%) is achieved, representing the highest efficiency reported for 300 nm thick OSCs thus far. Additionally, blade-coated thick device (300nm) delivers a promising PCE of 17.38%. This work brings new insights into the construction of efficient OSCs with high thickness tolerance, showing great potential for roll-to-roll printing of large-area solar cells.

Synthesis and characterization of supramolecular assembly probenecid cocrystal

To improve the bioavailability and provide a lead compound for developing formulations of the highly water-insoluble prodrug probenecid (PRO), enhancing its solubility is a crucial challenge that needs to be addressed. Herein, we report the synthesis and solid-state characterization of a new pharmaceutical cocrystal, PRO-BPE, synthesized using trans-1,2-bis(4-pyridyl)ethylene (BPE) to improve the solubility of PRO. The PRO-BPE cocrystals were characterized using various analytical techniques, including differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, Fourier transform-infrared spectroscopy, and X-ray powder diffraction. Single-crystal X-ray diffraction was performed to determine the crystal structure of PRO-BPE. PRO-BPE crystallized in the triclinic crystal system P-1 space group and its asymmetric unit consists of half a BPE molecule and one PRO molecule. The N1 atoms located at both ends of the BPE molecule form stable hydrogen bonds with two PRO carboxyl hydrogens through N1···H4—O4 (1.777 Å, 166.78°) interactions, whereas the O3 atoms of the carboxylic groups form C1—H1···O3 (2.479 Å, 132.10°) hydrogen bonds with two pyridyl hydrogens, resulting in a stable seven-membered ring structure. Furthermore, these fragments are further assembled via C—H···O intermolecular interactions to form a two-dimensional layered structure. Interestingly, the two pyridyl rings of each BPE molecule engage in π···π interactions with the benzene rings of two other non-coplanar PRO molecules. Finally, a three-dimensional framework structure is formed through intramolecular non-covalent interactions. Comprehensive characterization analyses provided further information regarding PRO-BPE cocrystal formation. Based on the equilibrium solubility results, the water solubility of the PRO-BPE cocrystal was superior to that of pure PRO, with an increase of 2.43 times. In summary, this study provides the first evidence that cocrystals could enhance the solubility of PRO and offers valuable insights into the solid-state properties of PRO-BPE cocrystals.

Near-infrared non-fused electron acceptors for efficient organic photovoltaics

Developing narrow-bandgap organic semiconductors is important to facilitate the advancement of organic photovoltaics (OPVs). Herein, two near-infrared non-fused ring acceptors (NIR NFRAs), PTBFTT-F and PTBFTT-Cl have been developed with A-πA-πD-D-πD-πA-A non-fused structures. It is revealed that the introduction of electron deficient π-bridge (πA) and multiple intramolecular noncovalent interactions effectively retained the structural planarity and intramolecular charge transfer of NFRAs, extending strong NIR photon absorption up to 950 nm. Further, the chlorinated acceptor, with the enlarged π-surface compared to the fluorinated counterpart, promoted not only molecular stacking in solid, but also the desirable photochemical stability in ambient, which are helpful to thereby improve the exciton and charge dynamics for the corresponding OPVs. Overall, this work provides valuable insights into the design of NIR organic semiconductors.

Long but Strong C-C Single Bonds: Challenges for Theory.

Theoretical challenges in describing molecules with anomalously long single C-C bonds are analyzed in terms of the relative contributions of stabilizing and destabilizing intramolecular interactions. Diamondoid dimers that are stable despite the presence of C-C bonds up to 1.7 Å long, as well as other bulky molecules stabilized due to intramolecular noncovalent interactions (London dispersions) are discussed. The unexpected stability of highly crowded molecules, such as diamondoid dimers and tert-butyl-substituted hexaphenylethanes, calls for reconsideration of the "steric effect" traditionally thought to destabilize the molecule. Alternatively, "steric attraction" helps to understand bonding in sterically overloaded molecules, whose structural and energetic analysis requires a proper theoretical description of noncovalent interactions.

Highly efficient and stable thermally activated delayed fluorescent palladium(II) complexes for organic light-emitting diodes

Transition metal complexes exhibiting thermally activated delayed fluorescence (TADF) remain underdeveloped for organic light-emitting diodes (OLEDs). Here, we describe a design of TADF Pd(II) complexes featuring metal-perturbed intraligand charge-transfer excited states. Two orange- and red-emitting complexes with efficiencies of 82 and 89% and lifetimes of 2.19 and 0.97 μs have been developed. Combined transient spectroscopic and theoretical studies on one complex reveal a metal-perturbed fast intersystem crossing process. OLEDs using the Pd(II) complexes show maximum external quantum efficiencies of 27.5 to 31.4% and small roll-offs down to 1% at 1000 cd m −2 . Moreover, the Pd(II) complexes show exceptional operational stability with LT 95 values over 220 hours at 1000 cd m −2 , benefiting from the use of strong σ-donating ligands and the presence of multiple intramolecular noncovalent interactions beside their short emission lifetimes. This study demonstrates a promising approach for developing efficient and robust luminescent complexes without using the third-row transition metals.

Realizing High-Efficiency Orange-Red Thermally Activated Delayed Fluorescence Materials through the Construction of Intramolecular Noncovalent Interactions.

The development of highly efficient orange and red thermally activated delayed fluorescence (TADF) materials for constructing full-color and white organic light-emitting diodes (OLEDs) remains insufficient because of the formidable challenges in molecular design, such as the severe radiationless decay and the intrinsic trade-off between the efficiencies of radiative decay and reverse intersystem crossing (RISC). Herein, we design two high-efficiency orange and orange-red TADF molecules by constructing intermolecular noncovalent interactions. This strategy could not only ensure high emission efficiency via suppression of the nonradiative relaxation and enhancement of the radiative transition but also create intermediate triplet excited states to ensure the RISC process. Both emitters exhibit typical TADF characteristics, with a fast radiative rate and a low nonradiative rate. Photoluminescence quantum yields (PLQYs) of the orange (TPA-PT) and orange-red (DMAC-PT) materials reach up to 94 and 87%, respectively. Benefiting from the excellent photophysical properties and stability, OLEDs based on these TADF emitters realize orange to orange-red electroluminescence with high external quantum efficiencies reaching 26.2%. The current study demonstrates that the introduction of intermolecular noncovalent interactions is a feasible strategy for designing highly efficient orange to red TADF materials.

Covalently Linked Hexakis(m-Phenylene Ethynylene) Macrocycles as Molecular Nanotubes.

The construction of nanotubular structures with non-deformable inner pores is of both fundamental and practical significance. Herein we report a strategy for creating molecular nanotubes with defined lengths. Macrocyclic (MC) units based on shape-persistent hexakis(m-phenylene ethynylene) (m-PE) macrocycle MC-1, which are known to stack into hydrogen-bonded tubular assemblies, are tethered by oligo(β-alanine) linkers to give tubular stacks MC-2 and MC-4 that have two and four MC units, respectively. The covalently linked MC units in MC-2 and MC-4 undergo face-to-face stacking through intramolecular non-covalent interactions that further results in the helical stacks of these compounds. Oligomer MC-4 can form potassium and proton channels across lipid bilayers, with the channels being open continuously for over 60 seconds, which is among the longest open durations for synthetic ion channels and indicates that the thermodynamic stability of the self-assembling channels can be drastically enhanced by reducing the number of molecular components involved. This study demonstrates that covalently tethering shape-persistent macrocyclic units is a feasible and reliable approach for building molecular nanotubes that otherwise are difficult to create de novo. The extraordinarily long lifetimes of the ion channels formed by MC-2 and MC-4 suggest the likelihood of constructing the next-generation synthetic ion channels with unprecedented stability.

Combined NMR Spectroscopy and Quantum-Chemical Calculations in Fluorescent 1,2,3-Triazole-4-carboxylic Acids Fine Structures Analysis.

The peculiarities of the optical properties of 2-aryl-1,2,3-triazole acids and their sodium salts were investigated in different solvents (1,4-dioxane, dimethyl sulfoxide DMSO, methanol MeOH) and in mixtures with water. The results were discussed in terms of the molecular structure formed by inter- and intramolecular noncovalent interactions (NCIs) and their ability to ionize in anions. Theoretical calculations using the Time-Dependent Density Functional Theory (TDDFT) were carried out in different solvents to support the results. In polar and nonpolar solvents (DMSO, 1,4-dioxane), fluorescence was provided by strong neutral associates. Protic MeOH can weaken the acid molecules' association, forming other fluorescent species. The fluorescent species in water exhibited similar optical characteristics to those of triazole salts; therefore, their anionic character can be assumed. Experimental 1H and 13C-NMR spectra were compared to their corresponding calculated spectra using the Gauge-Independent Atomic Orbital (GIAO) method and several relationships were established. All these findings showed that the obtained photophysical properties of the 2-aryl-1,2,3-triazole acids noticeably depend on the environment and, therefore, are good candidates as sensors for the identification of analytes with labile protons.

A molecular descriptor of intramolecular noncovalent interaction for regulating optoelectronic properties of organic semiconductors

In recent years, intramolecular noncovalent interaction has become an important means to modulate the optoelectronic performances of organic/polymeric semiconductors. However, it lacks a deep understanding and a direct quantitative relationship among the molecular geometric structure, strength of noncovalent interaction, and optoelectronic properties in organic/polymeric semiconductors. Herein, upon systematical theoretical calculations on 56 molecules with and without noncovalent interactions (X···Y, X = O, S, Se, Te; Y = C, F, O, S, Cl), we reveal the essence of the interactions and the dependence of its strength on the molecular geometry. Importantly, a descriptor S is established as a function of several basic geometric parameters to well characterize the noncovalent interaction energy, which exhibits a good inverse correlation with the reorganization energies of the photo-excited states or electron-pumped charged states in organic/polymeric semiconductors. In particular, the experimental 1H, 77Se, and 125Te NMR, the optical absorption and emission spectra, and single crystal structures of eight compounds fully confirm the theoretical predictions. This work provides a simple descriptor to characterize the strength of noncovalent intramolecular interactions, which is significant for molecular design and property prediction.

Spectral, quantum chemical, biological activity, and molecular docking analysis of 1,8-dihydroxyanthraquinone: A target drug exploration

In this current effort, the 1H and 13C NMR spectra as well as quantum chemical computational effort of 1,8 DHAQ molecule analyzed based on density functional theory (DFT) with the help of Gauss-View 6.0.6 and Gaussian 09W program package. The molecular structure of 1,8 DHAQ optimized first through DFT/B3LYP hybrid functional/6-311++G (d,p) basis-set. The NMR (1H and 13C) isotropic chemical shift values of the titled molecule (TMS as reference) was examined through gauge-invariant-atomic orbital (GIAO) process in DMSO‑d6 polar solvent using above similar basis set, then was correlated with the experimental outcomes. All the findings of DHAQ molecule correlated very well with each other. Reduced Density Gradients (RDG Scatter plot) give an evidence of various non-covalent intramolecular interactions inside molecule. ELF and LOL analysis proof a chemical association of molecules. It also reveals the main localization & delocalization of boding and non-bonding electrons within molecule. An in-silico ADMET profiles (absorption, distribution, metabolism, excretion, and toxicity), bioactivity score, and drug-likeness (based on the Lipinski rules of five) of 1,8 DHAQ molecule was executed via various computational online server tools. This study predicts that titled molecule have noble physicochemical and pharmacokinetic properties. Furthermore, the inhibitory nature of the DHAQ molecule has estimated by means of molecular docking analysis using various selected target proteins. The molecular docking is an effective computational analysis in estimating the binding affinity and binding sites of ligand together with the target proteins, which is much effective for future structure-based drug designing. Thus, the formation of numerous hydrogen bonds and docked binding affinities depicts that hydroxy-substituted Anthraquinone might serve as main structure for the development of upcoming drugs. As a result, this effort provide a summary of the chemistry, biology, and toxicology of 1,8 DHAQ molecule, focusing on innovative drugs discovery for treatment of various cancer diseases in pharmaceutical industries.

Alkoxy-Functionalized Bithiophene/thiazoles: Versatile Building Blocks for High-Performance Organic and Polymeric Semiconductors

ConspectusOrganic electronics has experienced substantial advances in the past decade, driven by the development of high-performance organic semiconductors (OSCs) in combination with device engineering. While the pursuit of new aromatic building blocks has been a central topic in OSC innovation, the installation of novel side chains is also of significance for accessing high-performance solution-processable OSCs due to their great impact on (macro)molecular conformation/configuration, energy levels, intra/intermolecular interaction, and packing motifs, as well as film morphology of the materials.Compared to tuning the length, branching point, anchoring position, and terminal group of alkyl side chains, alkoxy functionalization can afford multifaceted advantages by modulating the properties of both π-conjugated main chains and side chain substituents. For instance, the oxygen atom in alkoxy chains not only greatly decreases the steric hindrance between adjacent aromatic rings due to its reduced van der Waal radius (∼1.4 Å) versus that of a CH2 moiety (∼2.0 Å) but also induces intramolecular noncovalent interaction for improving backbone coplanarity and charge transport properties. The highly electron-donating alkoxy chains can also greatly facilitate the intramolecular charge transfer (ICT), and hence the resulting semiconductors can yield absorption beyond the infrared region, which is essential for full coverage of solar absorption in photovoltaic devices. Additionally, the high polarity of oligo(ethylene glycol)-type alkoxy side chains can improve the miscibility of the OSCs with molecular dopants and ions, thus enabling them as a key part of the OSCs for emerging applications such as organic thermoelectrics and organic electrochemical transistors.In this Account, we summarize our pioneering and systematic efforts on the rational design, synthesis, and applications of novel alkoxy-functionalized head-to-head (HH)-linked bithiophene/thiazole-based building blocks and related organic/polymeric semiconductors. First, starting with a brief retrospective to the long pursuit of regioregular polythiophenes to avoid HH linkages for accessing highly planar polymers with high mobility, we introduce the basic design guidelines for developing alkoxy-functionalized bithiophene/thiazole-based building blocks via various molecular engineering strategies, including noncovalent interaction incorporation, symmetry-breaking, fluorination, cyanation, esterification, etc. In this part, the merits of HH-linked alkoxy-functionalized bithiophene/thiazoles in constructing high-performance OSCs will be elaborated. Then the principles of designing organic and polymeric semiconductors based on these building blocks toward applications in different optoelectronic devices will be further discussed. Afterward, we present recent examples of alkoxy-functionalized bithiophene/thiazoles-based materials which have delivered state-of-the-art performance in various optoelectronic devices, showing how the judicious structure tailoring of these building blocks can optimize the materials properties and device performance. Finally, we offer our insights into the further development of alkoxy-functionalized bithiophene/thiazoles-based derivatives and semiconductors for high-performance optoelectronic devices.

High-Efficiency and Low-Energy-Loss Organic Solar Cells Enabled by Tuning Conformations of Dimeric Electron Acceptors

Open AccessCCS ChemistryRESEARCH ARTICLES6 Jan 2023High-Efficiency and Low-Energy-Loss Organic Solar Cells Enabled by Tuning Conformations of Dimeric Electron Acceptors Xiaobin Gu, Yanan Wei, Na Yu, Jiawei Qiao, Ziyang Han, Qijie Lin, Xiao Han, Jinhua Gao, Congqi Li, Jianqi Zhang, Xiaotao Hao, Zhixiang Wei, Zheng Tang, Yunhao Cai, Xin Zhang and Hui Huang Xiaobin Gu Google Scholar More articles by this author , Yanan Wei Google Scholar More articles by this author , Na Yu Google Scholar More articles by this author , Jiawei Qiao Google Scholar More articles by this author , Ziyang Han Google Scholar More articles by this author , Qijie Lin Google Scholar More articles by this author , Xiao Han Google Scholar More articles by this author , Jinhua Gao Google Scholar More articles by this author , Congqi Li Google Scholar More articles by this author , Jianqi Zhang Google Scholar More articles by this author , Xiaotao Hao Google Scholar More articles by this author , Zhixiang Wei Google Scholar More articles by this author , Zheng Tang Google Scholar More articles by this author , Yunhao Cai Google Scholar More articles by this author , Xin Zhang Google Scholar More articles by this author and Hui Huang Google Scholar More articles by this author https://doi.org/10.31635/ccschem.023.202202575 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Dimeric fused-ring electron acceptors (DFREAs) have attracted much attention due to their combined advantages of monomeric and polymeric acceptors, including a well-defined molecular structure, excellent repeatability, and morphology stability. However, the additionally-introduced single-bonds during dimerization may result in a twisted backbone of DFREAs, which is detrimental to intermolecular packing and charge transport. Herein, three DFREAs are designed and synthesized, of which conformations were systematically tuned via adjusting the intensities of intramolecular noncovalent interactions (INIs) to achieve high performance organic solar cells (OSCs). Theoretical and experimental results show that the gradual introduction of S⋯F INIs can continuously improve molecular planarity and rigidity, resulting in reduced reorganization energies, ordered packing mode, and enhanced crystallization of DFREAs. Benefiting from the incorporation of four-fold S⋯F INIs, DYF-TF-based binary OSCs show a record high efficiency of 18.26% with an extremely low energy loss (0.493 eV) for DFREA-based OSCs. In addition, DYF-TF-based OSCs exhibited a good long-term stability with a T80% lifetime of 2681 h, and the PCE of the DYF-TF-based ternary device is further enhanced to 18.73%. This contribution demonstrates the great potential of the INIs strategy in achieving excellent DFREAs materials. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentVolume 0Issue jaPage: 1-61Supporting Information Copyright & Permissions© 2023 Chinese Chemical Society Downloaded 0 times PDF downloadLoading ...

Hint approach on Transthyretin folding/unfolding mechanism comprehension

Non-covalent intramolecular interactions play a key role in the protein folding process. Aminoacidic mutations or changes in physiological conditions such as pH and/or temperature variations can compromise intramolecular stability generating misfolding or unfolding proteins with consequent impairment of functionality and the triggering of pathological states. The intramolecular HINT scoring function recently implemented and validated, is proposed as a rapid and sensitive method for the evaluation of different conformational states characterizing destabilization processes. In this work, the stability of Transthyretin, whose denaturation is related to amyloid fibril formation, is evaluated by generating multiple structural mutated models under different pH conditions in comparison with experimental data. These results suggest that the HINT scoring function can be used for an accurate and rapid evaluation and computational prediction of the effects of structural changes on any protein system.

Solvent-soluble thiophene-benzene based electrochromic polymers as electrode materials for supercapacitor

The bis(alkoxy) group para-substituted para-phenylene (p-phenylene) based conjugated polymers exhibit good electronic property due to the existence of intra-molecular non-covalent interaction between oxygen and heteroatom. However, the strong inter-molecular aggregation inhibits the ionic transport of polymer. Here, the strategy of changing side chain substitution position is employed to improve the properties of conjugated polymer. Three organic solvent-soluble conjugated polymers based on the bis(hexyloxy) group ortho-substituted p-phenylene were synthesized. The three polymers display small dihedral angles between thiophene and benzene. As the conjugated chain length of repeat units increasing, the redox potentials of polymers decrease gradually. From P1 to P2 to P3, their optical absorption regions red shift gradually, leading to neutral polymers display yellow for P1, orange for P2, magenta for P3, respectively. And the three polymers display good electrochromic properties (coloration efficiency: 641 cm2 C−1; response time: 0.2 s; optical contrast: 54%). Also, P2 possess the specific capacitance value of 170 F g−1, which is higher than that of most reported soluble conjugated polymers. Combining energy storage and electrochromic performance of the three polymers, their visualization monitor of energy storage were investigated.

Substituent effects on helical structures and chiroptical properties of fused anthracenes with bulky phenyl groups

In order to investigate substituent effects on the structures and properties of the helically fused anthracene system, various bulky phenyl groups were introduced at the sterically crowded positions. Three derivatives with mesityl (Mes), 2,4,6-triisopropylphenyl (Tip), and pentafluorophenyl (C6F5) groups were synthesized by Pt-catalyzed cycloisomerization of the corresponding alkyne precursors. The X-ray crystallographic analyses revealed that the helical structures were significantly expanded along the helical axis in the order of steric size of the substituents, C6F5 < Mes < Tip. The structural features are discussed on the basis of intramolecular noncovalent interactions such as CH···π and π···π interactions. Enantiomers of the Tip and C6F5 derivatives, resolved by chiral HPLC, showed very intense bands in circular dichroism (CD) and circularly polarized luminescence (CPL) bands. In particular, the luminescence dissymmetry factor |glum| values of these enantiomers (ca. 0.012) were large for simple organic molecules. Regardless of the large structural changes, the substituent effects on the optical and chiroptical properties were rather small. This structure–property relationship is discussed with the aid of DFT calculations.

Simultaneously enhancing the planarity and electron-donating capability of donors for through-space charge transfer TADF towards deep-red emission.

Through-space charge transfer (TSCT) has been proven effective for designing thermally activated delayed fluorescence (TADF) emitters due to the separation of the frontier molecular orbitals. Although tuning of the interaction between the donor and acceptor by controlling the conformation is known to be crucial for the photophysical properties of TSCT excited states, it remains a challenge to realize efficient red and deep-red emissions. Herein, we designed two TSCT molecules, namely TPXZ-QX and TPXZ-2QX, by using oxygen-bridged triphenylamine (TPXZ) as the electron donor with enhanced planarity and electron-donating capability. With a face-to-face orientation of the donor and acceptor segments and close π-π contacts, the new emitters have strong intramolecular noncovalent donor-acceptor interactions. The emissions of TPXZ-QX and TPXZ-2QX in doped thin films lie in the red (λmax = 632 nm) to deep-red (λmax = 665 nm) region. The photoluminescence quantum yields are 41% and 32% for TPXZ-QX and TPXZ-2QX, respectively. Organic light-emitting diodes (OLEDs) based on TPXZ-QX and TPXZ-2QX show external quantum efficiencies (EQEs) of up to 13.8% and 11.4%, respectively. This work indicates that the modulation of TSCT excited states based on strong intramolecular cofacial π-stacking interactions is a viable choice for the development of high-efficiency long-wavelength TADF emitters.

Conformational control enables boroxine-to-boronate cage metamorphosis.

The discovery of molecular organic cages (MOCs) is inhibited by the limited organic-chemical space of the building blocks designed to fulfill strict geometric requirements for efficient assembly. Using intramolecular attractive or repulsive non-covalent interactions to control the conformation of flexible systems can effectively augment the variety of building blocks, ultimately facilitating the exploration of new MOCs. In this study, we introduce a set of boronic acid tripods that were designed using rational design principles. Conformational control was induced by extending the tripod's arms by a 2,3-dimethylbenzene unit, leading to the efficient formation of a tetrapodal nanometer-sized boroxine cage. The new building block's versatility was demonstrated by performing cage metamorphosis upon adding an aromatic tetraol. This led to a quantitative boroxine-to-boronate transformation and a topological shift from tetrahedral to trigonal bipyramidal.

Electron-Deficient Polycyclic Molecules via Ring Fusion for n-Type Organic Electrochemical Transistors.

The primary challenge for n-type small-molecule organic electrochemical transistors (OECTs) is to improve their electron mobilities and thus the key figure of merit μC*. Nevertheless, few reports in OECTs have specially proposed to address this issue. Herein, we report a 10-ring-fused polycyclic π-system consisting of the core of naphthalene bis-isatin dimer and the terminal moieties of rhodanine, which features intramolecular noncovalent interactions, high π-delocalization and strong electron-deficient characteristics. We find that this extended π-conjugated system using the ring fusion strategy displays improved electron mobilities up to 0.043 cm2 V-1 s-1 compared to our previously reported small molecule gNR, and thereby leads to a remarkable μC* of 10.3 F cm-1 V-1 s-1 in n-type OECTs, which is the highest value reported to date for small-molecule OECTs. This work highlights the importance of π-conjugation extension in polycyclic-fused molecules for enhancing the performance of n-type small-molecule OECTs.

Electron‐Deficient Polycyclic Molecules via Ring Fusion for n‐Type Organic Electrochemical Transistors

AbstractThe primary challenge for n‐type small‐molecule organic electrochemical transistors (OECTs) is to improve their electron mobilities and thus the key figure of merit μC*. Nevertheless, few reports in OECTs have specially proposed to address this issue. Herein, we report a 10‐ring‐fused polycyclic π‐system consisting of the core of naphthalene bis‐isatin dimer and the terminal moieties of rhodanine, which features intramolecular noncovalent interactions, high π‐delocalization and strong electron‐deficient characteristics. We find that this extended π‐conjugated system using the ring fusion strategy displays improved electron mobilities up to 0.043 cm2 V−1 s−1 compared to our previously reported small molecule gNR, and thereby leads to a remarkable μC* of 10.3 F cm−1 V−1 s−1 in n‐type OECTs, which is the highest value reported to date for small‐molecule OECTs. This work highlights the importance of π‐conjugation extension in polycyclic‐fused molecules for enhancing the performance of n‐type small‐molecule OECTs.

Radical scavenging capacity, UV activity, and molecular docking studies of 2ʹ, 5ʹ, 3, 4-Tetrahydroxychalcone: An insight into the photoprotection

A theoretical evaluation of radical scavenging activity and UV absorbing ability of chalcone named 2ʹ, 5ʹ, 3, 4-Tetrahydroxychalcone has been performed in the gas phase and aqueous media. The DFT-B3LYP/6–311+G (d, p) level of theory was utilized for geometry optimization and the calculation of reaction enthalpies, while the CAM-B3LYP/6–311+G (d, p) level of theory was employed for TDDFT analysis. Three potential working mechanisms of radical scavenging activity, hydrogen atom transfer mechanisms (HAT), stepwise electron transfer proton transfer (SET-PT), and sequential proton loss electron transfer mechanisms (SPLET) were investigated within the gas phase and aqueous phase. The results obtained demonstrate that the HAT will be the probable mechanism in the gas phase whereas SPLET will be in the water medium. Using the same level of theory, explicit surface analysis of the title compound was performed. The compound wave function analysis and molecular docking investigations were also performed in the optimized structure. The theoretical UV spectra were recorded in both the solvents and the compound's electronic absorption spectrum was analyzed using the TD-DFT method. The distribution of hole and electrons in the peaks of maximal oscillator strength corresponds to local excitation within the molecule. The Quantum Theory of Atoms in Molecule (QTAIM) was used to compute the strength of intramolecular hydrogen bonds and non-covalent interactions. The global reactivity parameters and electrostatic potential (ESP) were also included to define the reactivity of the whole molecule. The spin density distribution analysis was come upon to be complementary to the radical scavenging activity. Besides the radical scavenging activity of the compound, it can also be used as a potential UVA filter.