Synthesis of lateral macrobicyclic compartmental ligands: structural,magnetic, electrochemical,and catalytic studies of mono- and binuclear copper(II) complexes

A series of putative mono- and binuclear copper(II) complexes, of general formulas [CuL](ClO(4)) and [Cu(2)L](ClO(4))(2), respectively, have been synthesized from lateral macrocyclic ligands that have different compartments, originated from their corresponding precursor compounds (PC-1, 3,4:9,10-dibenzo-1,12-[N,N'-bis[(3-formyl-2-hydroxy-5-methyl)benzyl]diaza]-5,8-dioxacyclotetradecane; and PC-2, 3,4:9,10-dibenzo-1,12-[N,N'-bis[(3-formyl-2-hydroxy-5-methyl)benzyl]diaza]-5,8-dioxacyclopentadecane). The precursor compound PC-1 crystallized in the triclinic system with space group P(-)1. The mononuclear copper(II) complex [CuL(1a)](ClO(4)) is crystallized in the monoclinic system with space group P2(1)/c. The binuclear copper(II) complex [Cu(2)L(2c)](ClO(4))(2) is crystallized in the triclinic system with space group P(-)1; the two Cu ions have two different geometries. Electrochemical studies evidenced that one quasi-reversible reduction wave (E(pc) = -0.78 to -0.87 V) for mononuclear complexes and two quasi-reversible one-electron-transfer reduction waves (E(1)(pc) = -0.83 to -0.92 V, E(2)(pc) = -1.07 to -1.38 V) for binuclear complexes are obtained in the cathodic region. Room-temperature magnetic-moment studies convey the presence of antiferromagnetic coupling in binuclear complexes [mu(eff) = (1.45-1.55)mu(B)], which is also suggested from the broad ESR spectra with g = 2.10-2.11, whereas mononuclear complexes show hyperfine splitting in ESR spectra and they have magnetic-moment values that are similar to the spin-only value [mu(eff) = (1.69-1.72)mu(B)]. Variable-temperature magnetic susceptibility study of the complex shows that the observed -2J value for the binuclear complex [Cu(2)L(1b)](ClO(4))(2) is 214 cm(-1). The observed initial rate-constant values of catechol oxidation, using complexes as catalysts, range from 4.89 x 10(-3) to 5.32 x 10(-2) min(-1) and the values are found to be higher for binuclear complexes than for the corresponding mononuclear complexes.     

Ultrafast photoinduced charge separation resulting from self-assembly of a green perylene-based dye into pi-stacked arrays

Condensation of 3,4,5-tris(n-dodecyloxy)aniline with the green chromophore 1,7-bis(N-pyrrolidinyl)perylene-3,4;9,10-tetracarboxylic dianhydride yields N,N'-bis(3,4,5-tris(n-dodecyloxy)phenyl)-1,7-bis(N-pyrrolidinyl)perylene-3,4;9,10-bis(dicarboximide), 5PDI-TAP, which absorbs light strongly from 550 to 750 nm. 5PDI-TAP dissolves readily in methylcyclohexane (MCH), resulting in self-assembly into H-aggregates. Small-angle X-ray scattering data obtained on 10(-4) M solutions of 5PDI-TAP in MCH show that the aggregates are pi-stacked monodisperse pentamers. Femtosecond transient absorption spectroscopy on solutions of (5PDI-TAP)5 in MCH shows evidence of charge separation occurring with tau < or = 150 fs between adjacent stacked members of 5PDI-TAP within the pentamer followed by charge recombination with tau = 860 ps. Transmission electron microscopy of 5PDI-TAP films cast from solution show isolated bundles of columnar aggregates. (5PDI-TAP)n is a potentially useful material for organic photovoltaics because efficient photoinduced charge generation is an intrinsic property of the assembly.     

Bithiophene-imide-based polymeric semiconductors for field-effect transistors: synthesis, structure-property correlations, charge carrier polarity, and device stability

Developing new high-mobility polymeric semiconductors with good processability and excellent device environmental stability is essential for organic electronics. We report the synthesis, characterization, manipulation of charge carrier polarity, and device air stability of a new series of bithiophene-imide (BTI)-based polymers for organic field-effect transistors (OFETs). By increasing the conjugation length of the donor comonomer unit from monothiophene (P1) to bithiophene (P2) to tetrathiophene (P3), the electron transport capacity decreases while the hole transport capacity increases. Compared to the BTI homopolymer P(BTimR) having an electron mobility of 10(-2) cm(2) V(-1) s(-1), copolymer P1 is ambipolar with balanced hole and electron mobilities of ～10(-4) cm(2) V(-1) s(-1), while P2 and P3 exhibit hole mobilities of ～10(-3) and ～10(-2) cm(2) V(-1) s(-1), respectively. The influence of P(BTimR) homopolymer M(n) on film morphology and device performance was also investigated. The high M(n) batch P(BTimR)-H affords more crystalline film microstructures; hence, 3× increased electron mobility (0.038 cm(2) V(-1) s(-1)) over the low M(n) one P(BTimR)-L (0.011 cm(2) V(-1) s(-1)). In a top-gate/bottom-contact OFET architecture, P(BTimR)-H achieves a high electron mobility of 0.14 cm(2) V(-1) s(-1), only slightly lower than that of state-of-the-art n-type polymer semiconductors. However, the high-lying P(BTimR)-H LUMO results in minimal electron transport on exposure to ambient. Copolymer P3 exhibits a hole mobility approaching 0.1 cm(2) V(-1) s(-1) in top-gate OFETs, comparable to or slightly lower than current state-of-the-art p-type polymer semiconductors (0.1-0.6 cm(2) V(-1) s(-1)). Although BTI building block incorporation does not enable air-stable n-type OFET performance for P(BTimR) or P1, it significantly increases the OFET air stability for p-type P2 and P3. Bottom-gate/top-contact and top-gate/bottom-contact P2 and P3 OFETs exhibit excellent stability in the ambient. Thus, P2 and P3 OFET hole mobilities are almost unchanged after 200 days under ambient, which is attributed to their low-lying HOMOs (>0.2 eV lower than that of P3HT), induced by the strong BTI electron-withdrawing capacity. Complementary inverters were fabricated by inkjet patterning of P(BTimR)-H (n-type) and P3b (p-type).     

A highly pi-stacked organic semiconductor for field-effect transistors based on linearly condensed pentathienoacene

We present the synthesis and characterization of a fused-ring compound, dithieno[2,3-d:2',3'-d']thieno[3,2-b:4,5-b']dithiophene (pentathienoacene, PTA). In contrast to pentacene, PTA has a larger band gap than most semiconductors used in organic field-effect transistors (OFETs) and therefore is expected to be stable in air. The large pi-conjugated and planar molecular structure of PTA would also form higher molecular orders that are conductive for carrier transport. X-ray diffraction and atomic force microscopy experiments on its films show that the molecules stack in layers with their long axis upright from the surface. X-ray photoelectron spectroscopy suggests that there are no chemical bonds at the PTA/Au interface. OFETs based on the PTA have been constructed, and their performances as p-type semiconductors are also presented. A high mobility of 0.045 cm(2)/V s and an on/off ratio of 10(3) for a PTA OFET have been achieved, demonstrating the potential of PTA for application in future organic electronics.     

Competition between singlet fission and charge separation in solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene with sterically-encumbered perylene-3,4:9,10-bis(dicarboximide)s

The photophysics and morphology of thin films of N,N-bis(2,6-diisopropylphenyl)perylene-3,4:9,10-bis(dicarboximide) (1) and the 1,7-diphenyl (2) and 1,7-bis(3,5-di-tert-butylphenyl) (3) derivatives blended with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) were studied for their potential use as photoactive layers in organic photovoltaic (OPV) devices. Increasing the steric bulk of the 1,7-substituents of the perylene-3,4:9,10-bis(dicarboximide) (PDI) impedes aggregation in the solid state. Film characterization data using both atomic force microscopy and X-ray diffraction showed that decreasing the PDI aggregation by increasing the steric bulk in the order 1 < 2 < 3 correlates with a decrease in the density/size of crystalline TIPS-Pn domains. Transient absorption spectroscopy was performed on ~100 nm solution-processed TIPS-Pn:PDI blend films to characterize the charge separation dynamics. These results showed that selective excitation of the TIPS-Pn results in competition between ultrafast singlet fission ((1*)TIPS-Pn + TIPS-Pn → 2 (3*)TIPS-Pn) and charge transfer from (1*)TIPS-Pn to PDIs 1-3. As the blend films become more homogeneous across the series TIPS-Pn:PDI 1 → 2 → 3, charge separation becomes competitive with singlet fission. Ultrafast charge separation forms the geminate radical ion pair state (1)(TIPS-Pn(+?)-PDI(-?)) that undergoes radical pair intersystem crossing to form (3)(TIPS-Pn(+?)-PDI(-?)), which then undergoes charge recombination to yield either (3*)PDI or (3*)TIPS-Pn. Energy transfer from (3*)PDI to TIPS-Pn also yields (3*)TIPS-Pn. These results show that multiple pathways produce the (3*)TIPS-Pn state, so that OPV design strategies based on this system must utilize this triplet state for charge separation.     

2,7-diphenyl[1]benzoselenopheno[3,2-b][1]benzoselenophene as a stable organic semiconductor for a high-performance field-effect transistor

[1]Benzoselenopheno[3,2-b][1]benzoselenophene (BSBS) and its 2,7-diphenyl derivative (DPh-BSBS) were readily synthesized from diphenylacetylene and bis(biphenyl-4-yl)acetylene, respectively, with a newly developed straightforward selenocyclization protocol. In contrast to the parent BSBS that has poor film-forming properties, the diphenyl derivative DPh-BSBS formed a good thin film on the Si/SiO(2) substrate by vapor deposition. X-ray diffraction examination revealed that this film consists of highly ordered molecules that are nearly perpendicular to the substrate, making it suitable for use in the fabrication of organic field-effect transistors (OFETs). When fabricated at different substrate temperatures (room temperature, 60 degrees C, and 100 degrees C) in a "top-contact" configuration, all the DPh-BSBS-based OFET devices exhibited excellent p-channel field-effect properties with hole mobilities >0.1 cm(2) V(-1) s(-1) and current on/off ratios of approximately 10(6). This high performance was essentially maintained over 3000 continuous scans between V(g) = +20 and -100 V and reproduced even after storage under ambient laboratory conditions for at least one year.     

Bis(methylthio)tetracenes: synthesis, crystal-packing structures, and OFET properties

5,12-Bis(methylthio)tetracene (2) and 5,11-bis(methylthio)tetracene (3) were synthesized. DFT calculations indicate that the HOMO and LUMO energy levels of 2 and 3 are lowered by 0.13-0.24 eV and their HOMO-LUMO energy gaps are reduced by 0.1 eV relative to those of tetracene. X-ray crystallographic data revealed that 2 is arranged as a result of a 1-D slipped-cofacial π-stacking with S-S and S-π interactions, similar to the packing arrangement of 6,13-bis(methylthio)pentacene (1), whereas 3 exhibits a herringbone packing arrangement without S-S interactions. The OFET devices fabricated using spin-coated films of soluble 1 and 2, with a bottom-contact device configuration, exhibited hole mobilities as high as 1.3 × 10(-2) and 4.0 × 10(-2) cm(2) V(-1) s(-1) with current on/off ratios of over 10(5) and 10(4), respectively.     

Synthesis, structure, and magnetic properties of tetranuclear cubane-like and chain-like iron(II) complexes based on the N(4)O pentadentate dinucleating ligand 1,5-bis[(2-pyridylmethyl)amino]pentan-3-ol

The tetranuclear complexes [Fe(4)(pypentO)(pym)(3)(Oac)(NCS)(3)] x 1.5EtOH (1), [Fe(4)(pypentO)(pym)(Oac)(2)(NCS)(2)(MeO)(2)(H(2)O)] x H(2)O (2), [Fe(2)(pypentO)(NCO)(3)](2) (3), and [Fe(2)(pypentO)(N(3))(3)](2) (4) have been prepared, and their structure and magnetic properties have been studied (pypentOH = 1,5-bis[(2-pyridylmethyl)amino]pentan-3-ol, pymH = 2-pyridylmethanol). The X-ray diffraction analysis of 1 (C(43)H(53)N(10)O(7.5)S(3)Fe(4), monoclinic, P2(1)/n, a = 11.6153(17) A, b = 34.391(17) A, c = 14.2150(18) A, beta = 110.88(5) degrees, V = 5305(3) A(3), Z = 4) and 2 (C(31)H(45)N(7)O(10)S(2)Fe(4), monoclinic, C2/c, a = 19.9165(17) A, b = 21.1001(12) A, c = 21.2617(19) A, beta = 104.441(10) degrees, V = 8652.7(12) A(3), Z = 8) showed a Fe(4)O(4) cubane-like arrangement of four iron(II) atoms, four mu(3)-O bridging ligands, one (1) or two (2) syn-syn bridging acetates. The X-ray diffraction analysis of 3 (C(40)H(46)N(14)O(8)Fe(4), monoclinic, P2(1)/c, a = 11.7633(18) A, b = 18.234(3) A, c = 10.4792(16) A, beta = 99.359(18) degrees, V = 2217.7(6) A(3), Z = 2) and 4 (C(34)H(46)N(26)O(2)Fe(4), monoclinic, P2(1)/c, V = 4412.4(10) A(3), a = 23.534(3) A, b = 18.046(2) A, c = 10.4865(16) A, beta = 97.80(2) degrees, Z = 4) showed a zigzag bis-dinuclear arrangement of four iron(II) cations, two mu(2)-O bridging pypentO ligands, four mu(2)-N-cyanato bridging ligands (3) or four end-on azido bridging ligands (4): they are the first examples of cyanato and azido bridged discrete polynuclear ferrous compounds, respectively. The M?ssbauer spectra of 1 are consistent with four different high-spin iron(II) sites in the Fe(4)O(4) cubane-type structure. The M?ssbauer spectra of 3 are consistent with two high-spin iron(II) sites (N(5)O and N(4)O). Below 190 K, the M?ssbauer spectra of 4 are consistent with one N(5)O and two N(4)O high-spin iron(II) sites. The temperature dependence of the magnetic susceptibility was fitted with J(1) approximately 0 cm(-1), J(2) = -1.3 cm(-1), J(3) = 4.6 cm(-1), D = 6.4 cm(-1), and g = 2.21 for 1; J(1) = 2.6 cm(-1), J(2) = 2.5 cm(-1), J(3) = - 5.6 cm(-1), D = 4.5 cm(-1), and g = 2.09 for 2; J(1) = 1.5 cm(-1), J(2) = 0.2 cm(-1), D = - 5.6 cm(-1), D' = 4.5 cm(-1), and g = 2.14 for 3; and J(1) = - 2.6 cm(-1), J(2) = 0.8 cm(-1), D= 6.3 cm(-1), D' = 1.6 cm(-1), and g = 2.18 for 4. The differences in sign among the J(1), J(2), and J(3) super-exchange interactions indicate that the faces including only mu(3)-OR bridges exhibit ferromagnetic interactions. The nature of the ground state in 1-3 is confirmed by simulation of the magnetization curves at 2 and 5 K. In the bis-dinuclear iron(II) compounds 3 and 4, the J(2) interaction resulting from the bridging of two Fe(2)(pypentO)X(3) units through two pseudo-halide anions is ferromagnetic in 3 (X = mu(2)-N-cyanato) and may be either ferro- or antiferromagnetic in 4 (X = end-on azido). The J(1) interaction through the central O(alkoxo) and pseudo-halide bridges inside the dinuclear units is ferromagnetic in 3 (X = mu(2)-N-cyanato) and antiferromagnetic in 4 (X = end-on azido). In agreement with the symmetry of the two Fe(II) sites in complexes 3 and 4, D (pentacoordinated sites) is larger than D' (octahedral sites).     

Cation-dependent nuclearity of the copper-azido moiety: synthesis, structure, and magnetic study

Mono-, di-, and trinuclear copper-azido moieties have been synthesized by varying the size of the countercations. [Bu4N]+ yielded a [Cu2(N3)6]2- copper-azido moiety in [Bu4N]2[Cu2(mu(1,1)-N3)2(N3)4], 1, and [Pr4N]+ yielded a [Cu3(N3)8]2- moiety in {[Pr4N]2[Cu3(mu(1,1)-N3)4(N3)4]}n, 2, in which symmetry-related [Cu3(N3)8]2- moieties are doubly mu(1,1)-azido bridged to form unprecedented infinite zigzag chains parallel to the crystallographic a-axis. In the case of [Et4N]+, the mononuclear species [Et4N]2[Cu(N3)4], 3, has been formed. All complexes have been characterized structurally by single-crystal X-ray analysis: 1, C32H72N20Cu2, triclinic, space group P, a = 10.671(9) A, b = 12.239(9) A, c = 10.591(5) A, alpha = 110.01(4) degrees , beta = 93.91(5) degrees , gamma = 113.28(5) degrees , V = 1160.0(1) A3; 2, C24H56N26Cu3, monoclinic, space group P2(1)/n, a = 8.811(2) A, b = 37.266(3) A, c = 13.796(1) A, beta = 107.05(1) degrees , V = 4330.8(10) A(3); 3, C16H40N14Cu, tetragonal, space group I4/m, a = b = 10.487(1) A, c = 12.084(2) A, V = 1328.9(3) A3. The variable-temperature magnetic susceptibility measurements showed that although the magnetic interaction in [Bu4N]2[Cu2(mu(1,1)-N3)2(N3)4], 1, is antiferromagnetic (J = -36 cm(-1)), it is ferromagnetic in {[Pr4N]2[Cu3(mu(1,1)-N3)4(N3)4]}n, 2 (J = 7 cm(-1)). As expected, the [Et4N]2[Cu(N3)4] complex, 3, is paramagnetic.     

含杂原子的并五苯类似物合成及场效应性能研究

以N,N'-二苯基-1,4-苯二胺为原料, 合成了含硫和氮杂原子的并五苯类似物, 用可见-紫外吸收光谱和电化学测试对这类化合物进行表征, 确定了其光学带隙及轨道能级, 与并五苯相比它们具有低的最高占用分子轨道能级. 得到了三苯并二噻嗪的单晶结构, 分子具有平面结构, 分子间具有强的π…π相互作用和N…S相互作用. 首次将该类并五苯类似物应用于有机薄膜场效应晶体管中, 器件显示好的场效应特性, 迁移率为0.01 cm²·V^-1·s^-1.     

Spectroscopy and rectification of three donor-sigma-acceptor compounds, consisting of a one-electron donor (pyrene or ferrocene), a one-electron acceptor (perylenebisimide), and a C19 swallowtail

We report spectroscopic characterization and unimolecular rectification (asymmetric electrical conduction) measurements of three donor-sigma-acceptor (D-sigma-A) compounds N-(10-nonadecyl)-N-(1-pyrenylmethyl)perylene-3,4,9,10-bis(dicarboximide) (1), N-(10-nonadecyl)-N-(4-[1-pyrenyl]butyl)perylene-3,4,9,10-bis(dicarboximide) (2), and N-(10-nonadecyl)-N-(2-ferrocenylethyl)perylene-3,4,9,10-bis(dicarboximide) (3). These molecules were arranged as one-molecule thick Langmuir-Blodgett monolayers between Au electrodes. In such an "Au | D-sigma-A | Au" sandwich, molecule 1 is a unimolecular rectifier, with rather small rectification ratios (between 2 and 3 at +/-1 V) that decrease upon cycling. Molecule 2 does not rectify. Molecule 3 rectifies, with a rectification ratio of between 14 and 28 at +/-1 V; the through-film rectification and currents persist, even with scans of +/-2 V, for up to 40 cycles of measurement. Qualitative arguments, based on a two-level rectification mechanism, are consistent with the current asymmetries observed in the monolayers of 1 and 3.     

Highly sensitive phototransistor with crystalline microribbons from new π-extended pyrene derivative via solution-phase self-assembly

A new pyrene-cored π-conjugated molecule has been synthesized through Sonogashira coupling reaction. The single-crystalline microribbon-based FET exhibited the highest mobility of 0.7 cm(2) V(-1) s(-1) (I(on)/I(off) > 10(6)). Single-crystalline microribbons were employed to operate in an organic phototransistor (OPT) under very low light intensity (I = 5.6 μW cm(-2)).     

Excited singlet states of covalently bound, cofacial dimers and trimers of perylene-3,4:9,10-bis(dicarboximide)s

Perylene-3,4:9,10-bis(dicarboximide) (PDI) and its derivatives are robust organic dyes that strongly absorb visible light and display a strong tendency to self-assemble into ordered aggregates, having significant interest as photoactive materials in a wide variety of organic electronics. To better understand the nature of the electronics states produced by photoexcitation of such aggregates, the photophysics of a series of covalent, cofacially oriented, pi-stacked dimers and trimers of PDI and 1,7-bis(3',5'-di-t-butylphenoxy)perylene-3,4:9,10-bis(dicarboximide) (PPDI) were characterized using both time-resolved absorption and fluorescence spectroscopy. The covalent linkage between the chromophores was accomplished using 9,9-dimethylxanthene spacers. Placing n-octyl groups on the imide nitrogen atoms at the end of the PDI chromophores not attached to the xanthene spacer results in PDI dimers having near optimal pi-stacking, leading to formation of a low-energy excimer-like state, while substituting the more sterically demanding 12-tricosanyl group on the imides causes deviations from the optimum that result in slower formation of an excimer-like excited state having somewhat higher energy. By comparison, PPDI dimers having terminal n-octyl imide groups have two isomers, whose photophysical properties depend on the ability of the phenoxy groups at the 1,7-positions to modify the pi stacking of the PPDI molecules. In general, disruption of optimal pi-stacking by steric interactions of the phenoxy side groups results in excimer-like states that are higher in energy. The corresponding lowest excited singlet states of the PDI and PPDI trimers are dimer-like in nature and suggest that structural distortions that accompany formation of the trimers are sufficient to confine the electronic interaction on two chromophores within these systems. This further suggests that it may be useful to build into oligomeric PDI and PPDI systems some degree of flexibility that allows the structural relaxations necessary to promote electronic interactions between multiple chromophores.     

Conformationally gated switching between superexchange and hopping within oligo-p-phenylene-based molecular wires

We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Ph(n)), n = 1-4, and A = perylene-3,4:9,10-bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm(-1), respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, V(DA), measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower V(DA) via the energetically favored triplet pathway.     

Diketopyrrolopyrrole-containing quinoidal small molecules for high-performance, air-stable, and solution-processable n-channel organic field-effect transistors

We report the synthesis, characterization, and application of a novel series of diketopyrrolopyrrole (DPP)-containing quinoidal small molecules as highly efficient n-type organic semiconductors in thin film transistors (TFTs). The first two representatives of these species exhibit maximum electron mobility up to 0.55 cm(2) V(-1) s(-1) with current on/current off (I(on)/I(off)) values of 10(6) for 1 by vapor evaporation, and 0.35 cm(2) V(-1) s(-1) with I(on)/I(off) values of 10(5)-10(6) for 2 by solution process in air, which is the first demonstration of DPP-based small molecules offering only electron transport characteristics in TFT devices. The results indicate that incorporation of a DPP moiety to construct quinoidal architecture is an effective approach to enhance the charge-transport capability.     

Synthesis and Crystal Structure of N,N''- Bis(p-nitrophenyl)-2,2''-(p-phenylene- dioxy)diacetamide DMF Monohydrate

A new complex of N,N'-bis(p-nitrophenyl)-2,2'-(p-phenylene-dioxy) diacetamide DMF monohydrate, C25H25N5O9H2O (Mr = 557.52), has been synthesized and its structure was determined by X-ray crystallography method.The crystal belongs to monoclinic system, space group P21/c with a = 7.2812, b = 25.5894, c = 14.3434 (A), β = 91.110(1)o, V = 2672.0(2) (A)3, Dc = 1.386 g/cm3, F(000) = 1168, μ = 0.109 mm-1 and Z = 4.The final R = 0.0493 and wR = 0.1173 for 3389 observed reflections with I > 2σ(I).The asymmetric unit of the title complex consists of monomeric N,N'-bis(p-nitrophenyl)-2,2'-(p-phenyleneioxy)diacetamide 1, one DMF and one water molecule, which are incorporated during recrystallization.The molecules are linked into a three-dimensional network by π…π interactions as well as intermolecular interactions among DMF, water molecule and 1.     

Benzodicarbomethoxytetrathiafulvalene derivatives as soluble organic semiconductors

A series of new tetrathiafulvalene (TTF) derivatives bearing dimethoxycarbonyl and phenyl or phthalimidyl groups fused to the TTF core (6 and 15-18) has been synthesized as potential soluble semiconductor materials for organic field-effect transistors (OFETs). The electron-withdrawing substituents lower the energy of the HOMO and LUMO levels and increase the solubility and stability of the semiconducting material. Crystal structures of all new TTF derivatives are also described, and theoretical DFT calculations were carried out to study the potential of the crystals to be used in OFET. In the experimental study, the best performing device exhibited a hole mobility up to 7.5 × 10(-3) cm(2) V(-1) s(-1)).     

Low-temperature, high-performance, solution-processed indium oxide thin-film transistors

Solution-processed In(2)O(3) thin-film transistors (TFTs) were fabricated by a spin-coating process using a metal halide precursor, InCl(3), dissolved in acetonitrile. A thin and uniform film can be controlled and formed by adding ethylene glycol. The synthesized In(2)O(3) thin films were annealed at various temperatures ranging from 200 to 600 °C in air or in an O(2)/O(3) atmospheric environment. The TFTs annealed at 500 °C under air exhibited a high field-effect mobility of 55.26 cm(2) V(-1) s(-1) and an I(on)/I(off) current ratio of 10(7). In(2)O(3) TFTs annealed under an O(2)/O(3) atmosphere at temperatures from 200 to 300 °C exhibited excellent n-type transistor behaviors with field-effect mobilities of 0.85-22.14 cm(2) V(-1) s(-1) and I(on)/I(off) ratios of 10(5)-10(6). The annealing atmosphere of O(2)/O(3) elevates solution-processed In(2)O(3) TFTs to higher performance at lower processing temperature.     

Dithienosilole- and dibenzosilole-thiophene copolymers as semiconductors for organic thin-film transistors

The synthesis and physicochemical properties of a new class of thiophene/arenesilole-containing pi-conjugated polymers are reported. Examples of this new polymer class include the following: poly(2,5-bis(3',3' '-dihexylsilylene-2',2' '-bithieno)thiophene) (TS6T1), poly(2,5'-bis(3' ',3' '-dihexylsilylene-2' ',2' '-bithieno)bithiophene) (TS6T2), poly(2,5'-bis(2' ',2' '-dioctylsilylene-1' ',1' '-biphenyl)thiophene) (BS8T1), and poly(2,5'-bis(2' ',2' '-dioctylsilylene-1' ',1' '-biphenyl)bithiophene) (BS8T2). Organic field-effect transistors (OFETs) with hole carrier mobilities as high as 0.02-0.06 cm2/V s in air, low turn-on voltages, and current on/off ratios >105-106 are fabricated using solution processing techniques with the above polymers as the active channel layer. OFETs based on this polymer class exhibit excellent ambient operational stability.     

A (pi-extended tetrathiafulvalene)-fluorene conjugate. Unusual electrochemistry and charge transfer properties: the first observation of a covalent D(2+)-sigma-A(.-) redox state(1)

The synthesis of novel electrochemically amphoteric TTFAQ-sigma-A compounds (TTFAQ = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene, sigma = saturated spacer, A = polynitrofluorene acceptor) is reported. Their solution redox behavior is characterized by three single-electron reduction and one two-electron oxidation waves. Electrochemical quasireversibility of the TTFAQ(2+) state and a low E(ox) - E(red) gap ( approximately 0.25 V) for 3-(9-dicyanomethylene-4,5,7-trinitrofluorene-2-sulfonyl)-propionic acid 2-[10-(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracen-9-ylidene]-5-methyl-[1,3]dithiol-4-ylmethyl ester (10) has enabled the electrochemical generation of the hitherto unknown transient D(2+)-sigma-A(.-) state as observed in cyclic voltammetry and time-resolved spectroelectrochemistry. The ground state of compound 10 was shown to be ionic in the solid but is essentially neutral in solution (according to electron paramagnetic resonance). The X-ray structure of an intermolecular 1:2 complex between 2-[2,7-bis(2-hydroxyethoxy)-9,10-bis(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracene and 2,5,7-trinitro-4-bromo-9-dicyanomethylenefluorene, 14.(17)(2), reveals, for the first time, full electron transfer in a fluorene charge-transfer complex.