3,6-Dithiophen-2-yl-diketopyrrolo[3,2-b]pyrrole (isoDPPT) as an Acceptor Building Block for Organic Opto-Electronics

A croconic acid-derived narrow band gap conjugated microporous polymer

Croconic acid, a novel highly electron-deficient building block, was introduced into a conjugated microporous polymer (CTPA). The CMP possesses strong donor-acceptor interactions, which resulted in near-IR absorption (red edge ∼1350 nm), a narrow bandgap (<1 eV) and high electrical conductivity upon doping (0.1 S m^-1). Compared to the squaric acid congener (STPA), CTPA showed superior optical, electronic and electrical properties.

Design, Synthesis, and Bioactivity of Spiro Derivatives Containing a Pyridine Moiety

We designed and synthesized a series of pyridine spiro derivatives and evaluated their insecticidal and antiviral activities. Some compounds exhibited good insecticidal and antiviral activities. Notably, the E series of compounds displayed good insecticidal activity against Tetranychus urticae. Compounds E20 (EC₅₀ = 63.68 mg/L) and F4 (EC₅₀ = 47.81 mg/L) exhibited inactivation activities against the tobacco mosaic virus (TMV), which were similar to that of Ningnanmycin (EC₅₀ = 58.01 mg/L). Molecular docking showed that compounds E20 and F4 exhibited satisfactory affinities for the TMV coat protein (TMV-CP), with binding energies (-6.7 and -6.4 kcal/mol, respectively) slightly lower than that of Ningnanmycin (-6.3 kcal/mol). Further, molecular dynamics analysis revealed that compounds E20 and F4 exhibited better binding stability values than Ningnanmycin. Microscale thermophoresis showed that compounds E20 (K_d = 0.053 ± 0.016 μM) and F4 (K_d = 0.045 ± 0.022 μM) bound more strongly to TMV-CP than Ningnanmycin (K_d = 0.10 ± 0.029 μM). The results of transmission electron microscopy showed that these two compounds hindered the self-assembly and growth of TMV. In summary, we showed that these pyridine spiro derivatives could be used as a basis for the research and development of novel pesticides.

Diaza-1,3-butadienes as Useful Intermediate in Heterocycles Synthesis

Many heterocyclic compounds can be synthetized using diaza-1,3-butadienes (DADs) as key structural precursors. Isolated and in situ diaza-1,3-butadienes, produced from their respective precursors (typically imines and hydrazones) under a variety of conditions, can both react with a wide range of substrates in many kinds of reactions. Most of these reactions discussed here include nucleophilic additions, Michael-type reactions, cycloadditions, Diels–Alder, inverse electron demand Diels–Alder, and aza-Diels–Alder reactions. This review focuses on the reports during the last 10 years employing 1,2-diaza-, 1,3-diaza-, 2,3-diaza-, and 1,4-diaza-1,3-butadienes as intermediates to synthesize heterocycles such as indole, pyrazole, 1,2,3-triazole, imidazoline, pyrimidinone, pyrazoline, -lactam, and imidazolidine, among others. Fused heterocycles, such as quinazoline, isoquinoline, and dihydroquinoxaline derivatives, are also included in the review.

Recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells

Organic semiconductor materials, especially donor-acceptor (D-A) polymers, have been increasingly applied in organic optoelectronic devices, such as organic field-effect transistors (OFETs) and organic solar cells (OSCs). Plenty of high-performance OFETs and OSCs have been achieved based on varieties of structurally modified D-A polymers. As the basic building block of D-A polymers, acceptor moieties have drawn much attention. Among the numerous types, lactam- and imide-functionalized electron-deficient building blocks have been widely investigated. In this review, the structural evolution of lactam- or imide-containing acceptors (for instance, diketopyrrolopyrrole, isoindigo, naphthalene diimide, and perylene diimide) is covered and their representative polymers applied in OFETs and OSCs are also discussed, with a focus on the effect of varied structurally modified acceptor moieties on the physicochemical and photoelectrical properties of polymers. Additionally, this review discusses the current issues that need to be settled down and the further development of new types of acceptors. It is hoped that this review could help design new electron-deficient building blocks, find a more valid method to modify already reported acceptor units, and achieve high-performance semiconductor materials eventually.

Diketopyrrolopyrrole Based Organic Semiconductor Materials for Field-Effect Transistors

Over the past several decades, organic conjugated materials as semiconductors in organic field effect transistors (OFETs) have attracted more and more attention from the scientific community due to their intriguing properties of mechanical flexibility and solution processability. However, the device fabrication technique, design, and synthesis of novel organic semiconductor materials with high charge carrier mobility is crucial for the development of high-performance OFETs. In the past few years, more and more novel materials were designed and tested in the OFETs. Among which, diketopyrrolopyrrole (DPP) and its derivatives, as the electron acceptors to build donor-acceptor (D-A) typed materials, are the perspective. In this article, recently reported molecules regarding the DPP and its derivatives for OFETs application are reviewed. In addition, the relationship between the chemical structures and the performance of the device are discussed. Furthermore, an outlook of DPP-based materials in OFETs with a future design concept and the development trend are provided.

Pyrrolo[3,2-b]pyrrole-1,4-dione (IsoDPP) End Capped with Napthalimide or Phthalimide: Novel Small Molecular Acceptors for Organic Solar Cells

We introduce two novel solution-processable electron acceptors based on an isomeric core of the much explored diketopyrrolopyrrole (DPP) moiety, namely pyrrolo[3,2-b]pyrrole-1,4-dione (IsoDPP). The newly designed and synthesized compounds, 6,6'-[(1,4-bis{4-decylphenyl}-2,5-dioxo-1,2,4,5-tetrahydropyrrolo[3,2-b]pyrrole-3,6-diyl)bis(thiophene-5,2-diyl)]bis[2-(2-butyloctyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione] (NAI-IsoDPP-NAI) and 5,5'-[(1,4-bis{4-decylphenyl}-2,5-dioxo-1,2,4,5-tetrahydropyrrolo[3,2-b]pyrrole-3,6-diyl)bis(thiophene-5,2-diyl)]bis[2-(2-butyloctyl)isoindoline-1,3-dione] (PI-IsoDPP-PI) have been synthesized via Suzuki couplings using IsoDPP as a central building block and napthalimide or phthalimide as end-capping groups. The materials both exhibit good solubility in a wide range of organic solvents including chloroform (CF), dichloromethane (DCM), and tetrahydrofuran (THF), and have a high thermal stability. The new materials absorb in the wavelength range of 300-600 nm and both compounds have similar electron affinities, with the electron affinities that are compatible with their use as acceptors in donor-acceptor bulk heterojunction (BHJ) organic solar cells. BHJ devices comprising the NAI-IsoDPP-NAI acceptor with poly(3-n-hexylthiophene) (P3HT) as the donor were found to have a better performance than the PI-IsoDPP-PI containing cells, with the best device having a VOC of 0.92 V, a JSC of 1.7 mAcm-2, a FF of 63%, and a PCE of 0.97%.

Direct comparison of dithienosilole and dithienogermole as π-conjugated linkers in photosensitizers for dye-sensitized solar cells

Dithienosilole (DTS) and dithienogermole (DTG) are useful building units of π-conjugated organic materials. In the present work, donor-π-acceptor (D-π-A) dyes with bis(dihexyloxyphenyl)aminophenyl, DTS or DTG, and pyridine or cyanoacrylic acid as the donor (D), the π-conjugated linker (π), and the acceptor (A) units, respectively, were prepared and their optical properties were investigated. The D-π-A dyes exhibited strong absorption in the visible region, indicating efficient intramolecular donor-acceptor interaction. The addition of trifluoroacetic acid to solutions of pyridine-containing dyes led to red-shifts of the absorption bands as a result of pyridinium salt formation. Similar red-shifts were observed for cyanoacrylic acid dyes, which were due to the enhanced formation of neutral dyes relative to the separated ion pairs. The D-π-A dyes, however, showed similar absorption spectra when attached to the TiO2 surface, indicating that the dye-TiO2 electronic interaction was rather weak. In contrast to the finding that these dyes exhibited similar optical properties regardless of the π-linker (i.e., DTS or DTG), dye-sensitized solar cells (DSSCs) based on DTG-containing dyes exhibited superior performance compared to those based on DTS-containing dyes. Electrochemical impedance spectroscopy measurements supported the higher performance of the DSSCs with DTG-containing dyes.

Conjugated Polymers Containing Building Blocks 1,3,4,6-Tetraarylpyrrolo[3,2-b]pyrrole-2,5-dione (isoDPP), Benzodipyrrolidone (BDP) or Naphthodipyrrolidone (NDP): A Review

π-Conjugated organic donor-acceptor (D-A) type polymers are widely developed and used in electronic device. Among which, diketopyrrolopyrrole (DPP)-based polymers have received the most attention due to their high performances. The novel chromophores named 1,3,4,6-tetraarylpyrrolo[3,2-b]pyrrole-2,5-dione (isoDPP), benzodipyrrolidone (BDP) and naphthodipyrrolidone (NDP) are resemble DPP in chemical structure. IsoDPP is an isomer of DPP, with the switching position of carbonyl and amide units. The cores of BDP and NDP are tri- and tetracyclic, whereas isoDPP is bicyclic. π-Conjugation extension could result polymers with distinct optical, electrochemical and device performance. It is expected that the polymers containing these high-performance electron-deficient pigments are potential in the electronic device applications, and have the potential to be better than the DPP-based ones. IsoDPP, BDP, and NDP based polymers are synthesized since 2011, and have not receive desirable attention. In this work, the synthesis, properties (optical and electrochemical characteristics), electronic device as well as their relationship depending on core-extension or structure subtle optimization have been reviewed. The final goal is to outline a theoretical scaffold for the design the D-A type conjugated polymers, which is potential for high-performance electronic devices.

Structural and Electronic Origin of Bis-Lactam-Based High-Performance Organic Thin-Film Transistors

We describe herein the comprehensive theoretical and experimental studies on the transistor mobility of organic semiconductors by correlating a two-dimensional (2D) intermolecular interaction with thin-film morphology and the electronic coupling structure. We developed a novel bis-lactam-based small molecule, 1,5-dioctyl-3,7-di(thiophen-2-yl)-1,5-naphthyridine-2,6-dione (C8-NTDT), with a 2D-type C-H···O═C intermolecular interaction along the in-plane directions of the crystal packing structure, which is characteristically different from the one-dimensional-type intermolecular interaction shown in the typical bis-lactam molecule of 2,5-dioctyl-3,6-di(thiophen-2-yl)pyrrolo[3,4- c]pyrrole-1,4-dione (C8-DPPT). Experimentally and theoretically, C8-NTDT exhibited more favorable thin-film morphology and an electronic coupling structure for charge transport because of its unique 2D intermolecular interactions compared with C8-DPPT. In fact, C8-NTDT exhibited a hole mobility of up to 1.29 cm² V^-1 s^-1 and an on/off ratio of 10⁷ in a vacuum-processed device. Moreover, the high solubility with the 2D electronic coupling structure of C8-NTDT enables versatile solution processing for device fabrication without performance degradation compared to the vacuum-processed device. As an example, we could demonstrate a hole mobility of up to 1.10 cm² V^-1 s^-1 for the spin-coated devices, which is one of the best performances among the solution-processed organic field-effect transistors based on bis-lactam-containing small molecules.

Design and synthesis of novel 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone moiety as potential fungicides

BACKGROUND

Tetramic acid, thiophene and hydrazone derivatives were found to exhibit favorable antifungal activity. Aiming to discover novel template molecules with potent antifungal activity, a series of novel 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives containing a hydrazone group were designed, synthesized, and evaluated for their antifungal activity.

RESULTS

The structures of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were confirmed by FT-IR, 1H NMR, 13C NMR, 1H-1H NOESY, EI-MS and elemental analysis. Antifungal assays indicated that some title compounds exhibited antifungal activity against Fusarium graminearum (Fg), Rhizoctorzia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc) in vitro. Strikingly, the EC50 value of 5e against Rs was 1.26 µg/mL, which is better than that of drazoxolon (1.77 µg/mL). Meanwhile, title compounds 5b, 5d, 5e-5g, 5n-5q and 5t exhibited remarkable anti-Cc activity, with corresponding EC50 values of 7.65, 9.97, 6.04, 6.66, 7.84, 7.59, 9.47, 5.52, 6.41 and 7.53 µg/mL, respectively, which are better than that of drazoxolon (19.46 µg/mL).

CONCLUSIONS

A series of 3-(thiophen-2-yl)-1,5-dihydro-2H-pyrrol-2-one derivatives bearing a hydrazone group were designed, synthesized and evaluated for their antifungal activity against Fg, Rs, Bc and Cc. Bioassays indicated that some target compounds exhibited obvious antifungal activity against the above tested fungi. These results provide a significant basis for the further structural optimization of tetramic acid derivatives as potential fungicides.

Thionating iso-diketopyrrolopyrrole-based polymers: from p-type to ambipolar field effect transistors with enhanced charge mobility

Two polymers based on isoDPP and isoDTPP were designed and synthesized. Thionation reactions could transform p-type polymers into ambipolar polymers for field effect transistors with enhanced charge mobility.

A thiocarbonyl-containing small molecule for optoelectronics

We report the synthesis, characterization, and device properties of a novel thiocarbonyl iso-DPP derivative, namely 1,3,4,6-tetraphenylpyrrolo[3,2-b]pyrrole-2,5(1H,4H)-dithione.

Symmetrical N-acylsubstituted dihydrazones containing bithiophene core--Photophysical, electrochemical and thermal characterization

Four symmetrical N-acylsubstituted dihydrazones containing bithiophene core were synthesized from condensation of 2,2'-bithiophene-5,5'-dicarboxyaldehyde with benzoic, isonicotinoyl, 2-thiophenic and 2-furoic hydrazide. The obtained compounds were characterized through the data from (1)H nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), elemental analysis, UV-vis absorption spectroscopy, photoluminescence (PL), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements. Additionally, the electronic properties including orbital energies and resulting energy gaps were calculated by density functional theory (DFT). Their thermal behavior was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). They were thermal sable up to 320°C. The prepared N-acylsubstituted dihydrazones emitted light with λ(em) in the range of 499-530 nm in solution, whereas, in solid state as blend with PMMA blue emission was observed. They undergo quasi-reversible and irreversible electrochemical reduction and oxidation processes, respectively. Additionally, the selected compounds were tested preliminary as component of active layer in organic photovoltaic cells. The highest value of power conversion efficiency, equal to 1.68% under simulated 100 mW/cm(2) AM 1.5G irradiation was found for device with the architecture ITO/PEDOT:PSS/P3HT:PCBM:FBTH (1:2:2)/Al.

Electrochemical polymerization of 1,3,4,6-tetraarylpyrrolo[3,2-b]pyrrole-2,5-dione (isoDPP) derivatives

Electrochemical polymerization of tetraaryldiketopyrrolo[3,2-b]pyrrole (isoDPP) derivatives leads to deeply coloured low band gap polymers with reversible oxidation and reduction behaviour and electrochromic properties.

Third-generation solar cells: a review and comparison of polymer:fullerene, hybrid polymer and perovskite solar cells

Third-generation solar cells have excellent potential for delivering large scale, low-cost solar electricity. We review and compare the current understanding of the operation principles, performance improvements and future prospects for polymer:fullerene, hybrid polymer and perovskite solar cells.

Benzo[f]benzo[5,6]indolo[3,2-b]indole: a stable unsubstituted 4nπ-electron acene with an antiaromatic 1,4-diazapentalene core

A stable unsubstituted 4nπ-electron acene with an antiaromatic 1,4-diazapentalene core was prepared via an unprecedented mild oxidation. Further investigation showed that the stability of such acenes was dependent on the fusion patterns of the peripheryl benzene rings to the centre core.

The effect of diketopyrrolopyrrole (DPP) group inclusion in p-cyanophenyl end-capped oligothiophene used as a dopant in P3HT:PCBM BHJ solar cells

Synthesis and properties of DPP-(2TPhCN)2 dopant molecules, which absorb light and transfer energy to PC₆₀BM, increasing the BHJ cell efficiency.

Synthesis and properties of pyrrolo[3,4-c]pyrrole-1,3-dione based polymer semiconductors and their performance in organic thin film transistors

Pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione (1,3-DPP) is used as a building block to construct copolymers for organic thin film transistors.