O- and N-alkylated diketopyrrolopyrrole derivatives

The alkylation of 3-phenyl-6-(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione with 1-bromo-2-ethylhexane was performed. Besides the expected N,N′-dialkylated product, both possible N,O-dialkyl derivatives were isolated and identified for the first time. The position of the alkyl substituents in all three dialkylated isomers was determined by 2D ¹H and ¹³C NMR spectroscopy.     

Solid-state structure and optical properties of highly fluorescent diketopyrrolopyrrole derivatives synthesized by cross-coupling reaction

Diketopyrrolopyrrole (DPP) derivatives with four different substituents were synthesized by cross-coupling reactions. The DPP derivatives were investigated in terms of their solid-state structure, absorption, emission, and electrochemistry. The electron-donating property of each substituent causes a redshift of UV/vis absorption and emission in the solution state. Although all of the DPP derivatives have high quantum yields in solution, only butoxyphenyl-substituted DPP exhibits strong emission in the solid state.     

Theoretical study of chemosensor for fluoride anion and optical properties of the derivatives of diketopyrrolopyrrole

Spin trapping of hydroperoxyl radical (HOO^·) by the amide-linked conjugate of 5-carbamoyl-5-methyl-1-pyrroline N-oxide (AMPO) to β-cyclodextrin (β-CD) was studied computationally using a two-layered ONIOM method. From a conformational perspective, the “internal” conformation of 5R-β-CD-AMPO is more favored than the “external” conformation in which the nitrone is located outside of the cavity of the β-CD. When the HOO^· addition product is formed, the most stable isomer has the nitroxyl (N₁–O₁) moiety pointing inside the cavity of the β-CD. Thus, this “internal” conformation might protect the N₁–O₁ moiety of the resulting spin adduct from access by reducing agents, thereby improving the lifetime of the radical adduct. The computed energetic barrier for HOO^· addition to the 5R-β-CD-AMPO is 8.7?kcal/mol, which is marginally smaller than spin trapping by the non-conjugated AMPO (that is, without the β-CD). To optimize the reactivity of the β-CD-AMPO conjugate, the effect of a spacer unit between the AMPO segment and the β-CD moiety with varying methylene units, (CH₂) _n (n?=?1, 2, 3), on the energetics of HOO^· addition was evaluated. The structure with only one methylene spacer (n?=?1) appears to be optimal as determined by the smaller activation barrier (6.2?kcal/mol) for HOO^· addition to the nitrone moiety. Compared with very time-consuming quantum mechanical methods, the ONIOM method appears to offer significant advantages for evaluation of the best β-CD-AMPO conjugate for trapping of such reactive oxygen species and providing for the rational design of novel nitrones as spin traps.     

Valence electronic properties of n-channel organic materials based on fluorinated derivatives of perylene diimides

The valence electronic states of three kinds of fluorinated derivatives of perylene diimides, D2MFPP, D3MFPP, and D4MFPP, on Cu(110) and SiO(2)Si surface were studied by photoemission and density functional calculations. When these organic molecules were deposited on the Cu(110) and thermally oxidized SiO(2) surfaces, five well-resolved photoemission features originating from the molecules were observed. On Cu(110) surface, two emission features with pi-like character increased their binding energy with increasing the coverage of organic molecule, indicating a strong interaction between the organic molecules and Cu substrate. The density functional calculations suggest flat-lying adsorption geometry for D3MFPP and D4MFPP on Cu(110) surface.     

1-苯甲酰基-3-取代苯基硫脲的合成及其倍频性能

自 1 986年Ｈ .Ａｂｅｒ-Ｈａｌｉｍ[1 ] 等首次对含硫有机化合物进行有机非线性光学性能研究以来 ,含硫有机化合物的倍频性能越来越受人们的重视。尿素是脲类化合物中发现较早的一种有机非线性光学材料 ,它的分子非线性系数低、易吸湿但它的透光性能好 ,透明区一直延伸到紫外区 ,并且具有很高的抗光伤阈值 ,可实现位相匹配 ,已成功应用于频率转换及其它方面。 1 -苯甲酰基 - 3-取代苯基硫脲 ,由于其不对称性强 ,引起吸收波段位移小 ,理论上符合ＮＬＯ分子设计要求。1　实验部分1 1　计算分子的ＮＬＯ性能是由分子的偶极距或生成热求导计算…     

Solution processable diketopyrrolopyrrole semiconductor: towards bio-electronic applications

In this paper, the possibility to use diketopyrrolopyrrole (DPP) for the construction of electrical devices designed to interact with animal cells was studied. For this purpose, the biocompatibility and electrical properties of the selected DPP derivative (3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethyl-hexyl)pyrrolo[3,4-c]pyrrole-1,4-dione) [referred as DPP(TBFu)₂] were researched. The electrical properties were studied using model organic field-effect transistors. Mainly investigated was under what conditions maximum charge carrier mobility can be achieved. Using the cumulative effect of self-assembled monolayers on dielectrics and electrodes and detailed thermal analysis of the DPP, a higher charge carrier mobility was achieved than has been previously reported (5.5?×?10^?3 cm² V^?1 s^?1). The biocompatibility was studied based on a culture of 3T3 fibroblasts. This research revealed that DPP(TBFu)₂ can be used in applications involving direct contact with living animal cells. The conclusions found with these model devices can be applied to components suitable for biosensing applications, e.g., water- or electrolyte-gated organic field-effect transistors.     

Zeolites as hosts for novel optical and electronic materials

A review of the use of zeolites as hosts for electronically active guest materials is presented. Metal, semiconductor and conductive polymer nanoparticles as electronic and optical material composites are reported with special emphasis on their synthesis.     

Electron crystallography and organic materials with non-linear optical properties

Results of electron microscopic studies of crystal structures of a number of bis-benzylidene cyclohexanones are presented. It is shown that some of these compounds are efficient crystalline non-linear optically active (NLO) chromophores with second harmonic generation (SHG) properties. Appropriately functionalized chromophores of this type can be used as a polycondensation comonomer to produce partly crystalline main-chain NLO-active polymers. Electron diffraction crystal structural data, obtained for very small crystals, allowed us to get reasonable estimations of macroscopic crystal NLO-coefficients, relating quantum-chemically calculated molecular first hyperpolarizability components to crystal axes.     

Theoretical study of electronic properties of organic photovoltaic materials

It has been proved that fullerene derivatives, in which an oligophenylenevinylene (OPV) group is attached to C(60), present an interesting photophysical phenomenon and can be incorporated into photovoltaic cells. In these systems, the OPV acts as electron donor upon excitation, and then fullerene absorbs photoexcited electrons. These new organic semiconductor materials offer the prospect of lower manufacturing costs and they present several advantages: easy fabrication, large area, flexible and light weight devices when compared with inorganic counter parts. In the present theoretical study, oligomeric chains of p-phenylenevinylene (n-PPV, n = 3-8 units) and C(60)-OPV hybrids have been studied by density functional theory (DFT). Electronic properties such as electronic absorption and emission spectra were calculated in order to determinate how the increment of spectroscopic units affects their electronic behavior. These properties were carried out with time dependent-density functional theory (TD-DFT) and ZINDO semiempirical method. The theoretical calculations of the structural properties of n-PPV and fullerene-OPV hybrids were obtained using PBE1PBE/6-31G and ONIOM two-layered version, respectively. All calculations were done with Gaussian 03W program package.     

Theoretical study of the optical and charge transport properties of star-shaped molecules with 1,3,5-triazine-core derivatives as organic light-emitting and organic solar cells materials

A series of D–π–A star-shaped molecules has been investigated theoretically by using density functional theory (DFT) to reveal their optical, electronic, and charge transport properties for applications in organic light-emitting diodes (OLEDs) and organic solar cells (OSCs). The calculated results show that their optical, electronic, and charge transport properties are affected by the different end groups and π-bridges. Our results reveal that the molecules under investigation can serve as OSCs donor materials and/or luminescent materials for OLEDs. In addition, all molecules are expected to be promising candidates for hole- and electron-transport materials. On the basis of the obtained results, we propose a rational way for the design of multifunctional materials for OLEDs and OSCs applications.     

Borazine-based conjugated derivatives: Structural,electronic, and optical properties

The structural characteristics, electronic properties, and nonlinear optical properties of borazine-based conjugated derivatives have been explored at B3LYP/6-311G(d,p) level. The effects of various electron donor and acceptor substituents (H, F, Cl, Br, Me, CF₃, NH₂, OH, COOH, CHO, NO₂) on the structure, polarizability, frontier orbitals, the most intense electronic transition, and hyperpolarizabilities have studied. Calculations show that NO₂-substituted molecules have lowest hardness, the largest isotropic polarizability and anisotropy of polarizability, and first hyperpolarizability.     

Recent advances of covalent organic frameworks in electronic and optical applications

Covalent organic frameworks (COFs) as an emerging class of porous materials have achieved remarkable progress in recent years. Their high surface area, low mass densities, highly ordered periodic structures, and ease of functionalization make COFs exhibit superior potential in gas storage and separation, optoelectronic device and catalysis. This mini review gives a brief introduction of COFs and highlights their applications in electronic and optical fields.     

Recent progress of electronic materials based on 2,1,3-benzothiadiazole and its derivatives: synthesis and their application in organic light-emitting diodes

2,1,3-Benzothiadiazole(BT) and its derivatives are very important acceptor units used in the development of photoluminescent compounds and are applicable for the molecular construction of organic light-emitting diodes, organic solar cells and organic field-effect transistors. Due to their strong electron-withdrawing ability, construction of molecules with the unit core of BT and its derivatives can usually improve the electronic properties of the resulting organic materials. In this contribution, we review the synthesis of various polymers, small molecules and metal complexes with BT and its derivatives and their applications in organic light-emitting diodes. Furthermore, the molecular design rules based on these cores are discussed.     

Synthesis and characterization of optical and redox properties of bithiophene-functionalized diketopyrrolopyrrole chromophores

A series of six new 2,2'-bithiophene-functionalized diketopyrrolopyrrole (DPP) dyes 7a-f bearing different electron-donating and electron-withdrawing substituents at the terminal thiophene units was synthesized by palladium-catalyzed cross-coupling reactions. The to date unknown diiodinated DPP 2 and the corresponding boronic ester derivative 3 could be prepared in high yields, and these are shown to be versatile building blocks for the synthesis of DPP-based molecular materials by Negishi, Stille, and Suzuki coupling. The influence of the peripheral substituents on the optical and electrochemical properties of the present series of DPP dyes 7a-f were investigated by UV/vis and steady-state fluorescence spectroscopy and cyclic voltammetry, revealing an appreciable effect on the electronic nature of these dyes. The diamino-substituted DPP derivative 7e exhibits a strong absorption band reaching in the near-infrared (NIR) region, which is a highly desirable feature for application in organic photovoltaics.     

Synthesis of diketopyrrolopyrrole (DPP) derivatives comprising bithiophene moieties

Herein we disclose an easily applicable method for the synthesis of diketopyrrolopyrrole (DPP) derivatives comprising bithiophene moieties, with different substituents on the nitrogen atoms (Me, n-octyl, 3,5-di-tert-butylbenzyl, Boc) and on the thiophene rings (C₆H₁₃, C₁₂H₂₅), in good yields and purities. A comparison is made between the previously described method from literature and our more efficient approach regarding number of steps, overall yields and ease of synthesis and purification.     

Structural,electronic, and optical properties of some new dithienosilole derivatives

Structural Chemistry - Structural, electronic, and optical properties of a series of organic semiconductors based on dithienosilole (DTS) and its derivatives were theoretically studied using...     

A conjugated polyazine containing diketopyrrolopyrrole for ambipolar organic thin film transistors

A π-conjugated polyazine containing diketopyrrolopyrrole (DPP) moiety, PDBTAZ, is synthesized through a simple condensation polymerization. PDBTAZ is found to be a high-performance ambipolar semiconductor in organic thin film transistors (OTFTs), showing an electron mobility of up to 0.41 cm(2) V(-1) s(-1) and a hole mobility of up to 0.36 cm(2) V(-1) s(-1).     

Optical properties of highly planar diketopyrrolopyrrole derivatives fixed by coordinate bonds

Diketopyrrolopyrrole (DPP) derivatives bearing 2-pyridyl groups were synthesized, which could serve as anionic N,N′-chelate ligands consisting of two nitrogen atoms of the lactam moieties and the pyridyl groups. Coordination of the DPP ligand to boron and platinum yielded the corresponding DPP complexes. Their crystal structures exhibited coplanar structures between the DPP core and the 2-pyridyl groups, which indicated extended π-conjugation. The maximum absorption wavelength of the DPP complexes was longer than that of the corresponding DPP ligands. The choice of the introduced element affects the optical properties of the DPP complexes; the platinum complex has a longer absorption wavelength than the boron complex. The theoretical calculation revealed that these absorptions can be attributed to the π–π* transition. The introduction of the coordinating elements predominantly lowers the band gap. In addition, the substituent on the 2-pyridyl group can also modulate the energy levels.     

Challenge to novel organic nonlinear optical materials for photonics application

Concepts and approaches toward the organic photonics research project pursued in our laboratory have been reviewed. Modification of electronic states in one dimensional conjugated polymers enables the creation of a quantum well structure. Carbazole containing oligomers and/or polymers show effective photorefractive effects applicable for image processing. A new technique to distinguish electronic and thermal nonlinearities has been demonstrated.     

Substituent effects on the electronic characteristics of pentacene derivatives for organic electronic devices: dioxolane-substituted pentacene derivatives with triisopropylsilylethynyl functional groups

The intramolecular electronic structures and intermolecular electronic interactions of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene), 6,14-bis-(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]-pentacene (TP-5 pentacene), and 2,2,10,10-tetraethyl-6,14-bis-(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]pentacene (EtTP-5 pentacene) have been investigated by the combination of gas-phase and solid-phase photoelectron spectroscopy measurements. Further insight has been provided by electrochemical measurements in solution, and the principles that emerge are supported by electronic structure calculations. The measurements show that the energies of electron transfer such as the reorganization energies, ionization energies, charge-injection barriers, polarization energies, and HOMO-LUMO energy gaps are strongly dependent on the particular functionalization of the pentacene core. The ionization energy trends as a function of the substitution observed for molecules in the gas phase are not reproduced in measurements of the molecules in the condensed phase due to polarization effects in the solid. The electronic behavior of these materials is impacted less by the direct substituent electronic effects on the individual molecules than by the indirect consequences of substituent effects on the intermolecular interactions. The ionization energies as a function of film thickness give information on the relative electrical conductivity of the films, and all three molecules show different material behavior. The stronger intermolecular interactions in TP-5 pentacene films lead to better charge transfer properties versus those in TIPS pentacene films, and EtTP-5 pentacene films have very weak intermolecular interactions and the poorest charge transfer properties of these molecules.