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Supplementary data to this article can be found online at https://doi.org/10.1016/j.cej.2023.141889., This work reports for the first time the functionalization of the 2-aminoterephtalate linker of UiO-66-NH2 with cyclopentyl or cyclohexyl rings. The resulting materials displayed reduced bandgaps with enhanced separation of the photogenerated charges due to the inductive electron effect of the cycloalkyl substituent. These functionalized materials displayed higher photocatalytic performance towards the solar abatement of acetaminophen than UiO-66-NH2. The photocatalytic activation mechanism was proposed based on the band alignment and scavenger tests, suggesting the major contribution of holes and superoxide radicals. In particular, UiO-66-NH-C5 exhibited high stability under reaction with low activity loss after reusing. The acetaminophen degradation pathway was also studied indicating that the ACE molecules were coupled to dimers and trimers that were further oxidized. The small bandgap, the band structure, and the photocatalytic performance resulting from the cycloalkyl functionalization of UiO-66-NH2 make it a promising approach to designing novel photocatalysts for solar abatement of emerging contaminants., Spanish State Research Agency (PID2019-106186RB-I00/AEI/10.13039/501100011033 and PID2019- 105479RB-I00 MCIN/AEI/10.13039/501100011033), Spanish Ministry of Science, Innovation, and Universities for his postdoctoral contract (Juan de la Cierva Formaci ́on, Ref. FJC2018- 035513-I), Support provided by the external services of the Autonomous University of Madrid (SIdI) and the Uni- versity of Extremadura (SAIUEx), Funding for open access charge: Universidad de Granada/CBUA

La proteína fosfatasa 2A (PP2A) es una importante Ser/Thr fosfatasa que participa en la regulación de múltiples procesos celulares. Esto implica que cualquier actividad deficiente de PP2A es responsable de graves patologías graves. Por ejemplo, una de las principales características histopatológicas de la enfermedad de Alzheimer son los ovillos neurofibrilares, que están compuestos principalmente por formas hiperfosforiladas de la proteína tau. Esta tasa alterada de fosforilación de tau se ha correlacionado con la depresión PP2A en pacientes con EA. Con el objetivo de prevenir la inactivación de PP2A en escenarios de neurodegeneración, nos hemos propuesto diseñar, sintetizar y evaluar nuevos ligandos de PP2A capaces de impidir su inhibición. Para lograr este objetivo, los nuevos ligandos PP2A presentan similitudes estructurales con el fragmento central C19-C27 del conocido inhibidor de PP2A ácido okadaico (AO). De hecho, este fragmento central de OA no ejerce acciones inhibidoras. Así, estos compuestos carecen de motivos estructurales inhibidores de PP2A pero, por contra, compiten con los inhibidores de PP2A, recuperando así la actividad fosfatasa. Demostrando esta hipótesis, la mayoría los compuestos mostraron un buen perfil neuroprotector en modelos de neurodegeneración relacionados con el deterioro de PP2A, destacando el derivado 10, denominado ITH12711, como el más prometedor. Este compuesto (1º) restauró la actividad catalítica de PP2A, medida en un sustrato fosfopéptido por Western blot, (2º) demostró una buena penetración cerebral medida por PAMPA, y (3º) evitó el deterioro de la memoria inducido por LPS en ratones sometidos a la prueba de reconocimiento de objetos. Por lo tanto, los prometedores resultados del compuesto 10 validan nuestra aproximación para diseñar nuevos fármacos activadores de PP2A basados en el fragmento central de OA.

The application of metal-free organic molecules grafted titanium dioxide (TiO2) as photocatalysts for the degradation of pharmaceuticals under solar light has been scarcely studied. Herein, a novel photocatalyst was synthesized anchoring a bipolar electron-donor and -acceptor molecule based on azaindole derivative (AZA4) onto TiO2 aiming to improve the photoactivity under simulated solar irradiation. The TiO2- azaindole (TiO2-AZA4) was fully characterized, confirming that AZA4 was successfully grafted onto TiO2 and improving the light absorption. The grafted TiO2 was applied in the photodegradation of acetaminophen in water, showing a significantly better photocatalytic performance compared to that of pure TiO2 under both solar and visible irradiations. AZA4 grafting leads to the TiO2 band gap narrowing and favors the charge separation, thus improving the TiO2 photoactivity. The photocatalytic performance of TiO2-AZA4 was evaluated using different conditions such as photocatalyst dose or initial pH of the solution, and the radical species involved in the process were investigated. The high activity of TiO2-AZA4 was confirmed in the photodegradation of a mixture of pharmaceuticals, namely acetaminophen, ibuprofen, and antipyrine, further demonstrating its stability and catalytic performance in a novel continuous flow test under simulated solar irradiation, thus finding a new strategy to design solar-light driven photocatalysts for the degradation of pollutants in water, Authors acknowledge Spanish Agencia Estatal de Investigación (PID2019- 106186RBI00/AEI/10.13039/501100011033 and PID2019-105479RB-I00 (MCIN/AEI/10.13039/501100011033)). M. Peñas-Garzón also thanks the Spanish Ministerio de Educación, Cultura y Deporte (FPU16/00576 grant). J. Álvarez-Conde acknowledges financial support from the European Social fund through ‘‘Programa de empleo juvenil y la iniciativa de empleo juvenil” (PEJD-2017-PRE/IND-4536) of the Government of Madrid. Authors thank the Research Support Services of the Universidad Autónoma de Madrid (SIdI), Universidad de Málaga (SCAI) and Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC)

In this paper, we explore the synthesis, characterization, and photophysical properties of a novel indigo derivative, N-octyl-7,7′-diazaindigo, being the first time that diazaindigos have been studied as photophysically-active chemical entities. Reduction of the neutral “keto-form” to the so-called “leuco-form” changes the global spectroscopic and photophysical behaviors. Both species have been investigated by different photophysical studies, such as analysis of absorption and emission spectra, fluorescence quantum yields (ΦF) and lifetimes. Finally, to appraise in depth the deactivation of the excited state of the keto form, femtosecond transient absorption (TA) experiments and Density Functional Theory (DFT) and Time Dependent (TD)-DFT calculations were performed. In an organic aprotic solvent (N,N-dimethylformamide), TA experiments showed a fast deactivation channel (τ1 = 2.9 ps), which was ascribed to solvent reorganization, and a longer decay component (τ2 = 86 ps) associated with an internal conversion (IC) process to the ground-state, in opposition to the excited state proton transfer (ESPT) mechanism that takes place in the indigo molecules but in protic solvents. A comparative study was also carried out on the parent molecule, 7,7′-diazaindigo, corroborating the previous conclusions obtained for the alkyl derivative. In agreement with experimental observations, DFT and TD-DFT calculations revealed that the deactivation of the S1 state of the keto form takes place through an internal conversion process.

Organic semiconductor micro/nanocrystals (OSMCs) have attracted great attention due to their numerous advantages such us free grain boundaries, minimal defects and traps, molecular diversity, low cost, flexibility and solution processability. Due to all these characteristics, they are strong candidates for the next generation of electronic and optoelectronic devices. In this review, we present a comprehensive overview of these OSMCs, discussing molecular packing, the methods to control crystallization and their applications to the area of organic solid-state lasers. Special emphasis is given to OSMC lasers which self-assemble into geometrically defined optical resonators owing to their attractive prospects for tuning/control of light emission properties through geometrical resonator design. The most recent developments together with novel strategies for light emission tuning and effective light extraction are presented.

N-Propargylamines are useful synthetic scaffolds for the synthesis of bioactive molecules, and in addition, they possess important pharmacological activities. We obtained several neuroprotective molecules, chiral 1,2-amino alcohols and 1,2-diamines, able to reduce by almost 70% the rotenone and oligomycin A-induced damage in SH-SY5Y cells. Furthermore, some molecules assessed also counteracted the toxicity evoked by the Ser/Thr phosphatase inhibitor okadaic acid. Before extrapolating these data to preclinical studies, we analyze the molecules through an in silico prediction system to detect carcinogenicity risk or other toxic effects. In light of these promising results, these molecules may be considered as a lead family of neuroprotective and relatively safe compounds.

Multitarget-directed ligands (MTDLs) are considered a promising therapeutic strategy to address the multifactorial nature of Alzheimer's disease (AD). Novel MTDLs have been designed as inhibitors of human acetylcholinesterases/butyrylcholinesterases, monoamine oxidase A/B, and glycogen synthase kinase 3β and as calcium channel antagonists via the Biginelli multicomponent reaction. Among these MTDLs, (±)-BIGI-3h was identified as a promising new hit compound showing in vitro balanced activities toward the aforementioned recognized AD targets. Additional in vitro studies demonstrated antioxidant effects and brain penetration, along with the ability to inhibit the aggregation of both τ protein and β-amyloid peptide. The in vivo studies have shown that (±)-BIGI-3h (10 mg/kg intraperitoneally) significantly reduces scopolamine-induced cognitive deficits., L.I. thanks the Regional Council of Franche-Comté (2016YC- 04540 and 04560) for financial support, Mrs. M.-J. Henriot (PHV Pharma) for her support in the HPLC analyses, and Vincent Luzet for preliminary results in synthesis. O.S., J.J., and J.K. acknowledge the support from the grant by Czech Science Foundation no. 20-29633J. T.K., D.J., and V.H. acknowledge support from the Long-term Development Plan (Faculty of Military Health Sciences). R.A. and K.M. thank the Ministry of Education, Youth and Sports of the Czech Republic (ERDF no. CZ.02.1.01/0.0/0.0/16_025/0007444).

In this paper, we explore the synthesis, characterization, and photophysical properties of a novel indigo derivative

In the last years, 7,7′-diazaisoindigo has emerged as a promising building block for semiconductor materials. In this work, we have studied different electronic properties, which can be related to the semiconducting character of a family of 7,7′-diazaisoindigo derivatives. Concretely, we have analyzed the role of halogen substituents and different side-chain lengths on these properties calculated by means of the density functional theory. In total, 16 halogenated and nonhalogenated diazaisoindigo derivatives were investigated. Four of these compounds were also synthetized, and their X-ray structures were employed as starting points for the calculation of the crystal structure of the rest of the novel compounds. In general, high electron-transfer rate constants and electron mobilities were calculated for the studied 7,7′-diazaisoindigo derivatives, especially for bromine derivatives and compounds with long side chains. The origin of these high rate constants mainly resides in the strong electronic coupling...

We report the synthesis and pharmacological evaluation of new 3-aminomethylindoles derivatives with neuroprotective properties designed to present multi-target activity centered on reducing the neuronal Ca2+ overload and preventing phosphatase 2A (PP2A) inhibition, which are two important early physiophathological events observed in neurodegenerative scenarios. Chemical syntheses of proposed compounds were achieved in two straightforward reaction steps with high yields. Most of the compounds mitigated the okadaic acid-provoked inhibition of PP2A and protected SH-SY5Y cells against toxic stimuli related to Tau-hyperphosphorylation and oxidative stress, similarly to the observed in Alzheimer's disease (AD). In addition, some of them mitigated the Ca2+ overload induced by depolarization. The derivative 1-(1-benzyl-5-chloro-1H-indol-3-yl)-N,N-dimethylmethanamine (19) outstood by its high recovery of the PP2A activity and blockade of voltage-gated Ca2+ channels, accompanied by good neuroprotective profile. These findings make this compound eligible for further preclinical assays with the goal of positioning new innovative drugs for the treatment of AD.

© 2019 The Royal Society of Chemistry. In this paper, a new D-A bipolar luminescent azaindole is synthesized and fully characterized. The triphenylamine (TPA) derivative acting as a hole-transporting unit (D) and 2-cyanoacrylic acid acting as an electron-transporting unit (A) are incorporated in the same molecule. This luminogen, based on azaindole, presents aggregation-induced emission (AIE) characteristics. The theoretical calculations together with the photophysical characterization show the potential applicability of this new compound as electroluminescent material for non-doped OLEDs. A double-layer light-emitting device was developed showing that the presence of a better acceptor group in the azaindole derivative can reduce the electroplex and electromer formation in favor of the electron-hole recombination in the HOMO-LUMO of the molecule. These results pointed out the importance of the molecular design of the emissive material for a better OLED performance. ispartof: JOURNAL OF MATERIALS CHEMISTRY C vol:7 issue:5 pages:1222-1227 status: published

Hybrid systems based on clay minerals and 7-azaindole derivatives, which show an interesting neuroprotective profile in several in vitro models of neurodegeneration, were developed in order to facilitate the oral administration of these drugs in the treatment of Alzheimer's disease and provide a controlled release. Two 7-azaindole derivatives with different substitution at position 5 (-OCH3, -H) were synthesized and adsorbed on nanocarriers of different morphology, the lamellar clay montmorillonite (MMT) and the halloysite nanotubes (HNT). The drugs intercalation in MMT was confirmed by X-ray diffraction, obtaining basal spacing values around 1.9–2.0 nm in the hybrids, with a drug loading around 31–36 g per 100 g of MMT, while the HNT-based hybrids show an uptake of 15–21 g per 100 g of HNT. Studies carried out in cultures of human neuroblastoma cells confirmed the lack of toxicity of the hybrids and their neuroprotective effect against okadaic acid (OA), the inhibitor of the protein phosphatase 2A (PP2A), similarly to the non-encapsulated drugs. The release assays carried out in systems that simulate the gastrointestinal tract show a rapid release of the drugs from the hybrid materials, making necessary their encapsulation in a protective biopolymer matrix to slow down the release kinetics. A blend of alginate and zein was chosen for this purpose, exploiting the gelation of alginate with calcium ions to process the material as microbeads and the hydrophobic character of zein to reduce the water uptake of the material. Therefore, these bionanocomposite systems integrating the drug/clay hybrids seem promising for the oral administration of drugs with multitarget activity for the treatment of Alzheimer's disease.

The reaction between 4,4′-diiodoazobenzene (0) with excess trimethylsilylacetylene or dec-1-yne in the presence of catalytic amounts of PdCl2(PPh3)2 and CuI, Sonogashira coupling conditions, gave rise to the formation of 4,4′-bis(trimethylsilylethynyl)azobenzene (1) and 4,4′-bis(dec-1-ynyl)azobenzene (2), in good yield, in addition to icosa-9,11-diyne (3) as byproduct in the last case. The analogous reactions from 0 and the alkynyl-cobalt complexes Co2(CO)4(μ-L-L)(μ2-η2-SiMe3C2)](C≡CH) (L-L = dppm, dmpm) afforded 12–14. Complexes 4–7 and 15 have been obtained by direct reaction between Co2(CO)8 and the organic ligands 1–3. In order to increase the stabilization of Co–Co bonds, diphenylphosphinomethane-substituted alkyne-carbonyl complexes 8–11 were prepared by substitution reaction of carbonyl ligands in the presence of Me3NO at the Co2(CO)6 units from 4–7. All products were characterized by analytical and spectroscopic data (IR, 1H, 13C, and 31P NMR, and MS). Crystals of 9 suitable for single-crystal X-ray diffraction were grown, and the molecular structure of this compound is discussed. In this paper we report a comparative electrochemical study of these complexes by means of cyclic and square-wave voltammetry techniques, the trans–cis photoisomerization study of azobenzene compounds, and the thermotropic liquid-crystalline behavior., Support for this work is acknowledged from the Comunidad de Madrid (FOTOCARBON-CM S2013/MIT-2841), Spain. Thanks to Joaquın Barbera ́ ́Gracia (Universidad de Zaragoza, Spain) for technical and scientific support.

A new luminescent azaindole derivative has been designed and synthesized to be implemented in a light-emitting device. The molecular geometry and frontier orbital energy have been investigated by using density functional theory. This newly synthesized molecule emits strongly both in solution and solid state. The fluorescence emission in THF upon addition of an increasing amount of HO has been measured also, displaying an increase of the fluorescence signal which is associated with an aggregation-induced emission phenomenon. Double-layer light-emitting devices including an active layer of the novel emissive material were successfully fabricated. The red-shift of the electroluminescence spectra with respect to the photoluminiscence emission was attributed to the presence of different types of complexes in the emissive material (EM) layer, which are preferentially formed between the nearest-neighbor hole-electron pairs of the electron injection and the EM layers (electroplex)., This work was financially supported by the Ministry of Economy and Competitiveness of Spain through Projects CTQ2013-40562-R and CTQ2014-56422-P. C.M. thanks the Research Foundation-Flanders for her postdoctoral fellowship. G.d.M. thanks the Ministry of Economy and Competitiveness for a “Ramón y Cajal” contract (RYC-2013-12772). The authors are also indebted to Belspo program through IAP VI/27 and VII/05 and to the KULeuven Research Fund through GOA 2011/3 and C14/15/053. The authors gratefully acknowledge financial support from the European Union’s Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 310651 SACS.

This study reports on the use of a self-assembling organogel, 5-(4-nonylphenyl)-7-azaindole (1), as a new emitter in small-molecule organic light emitting devices (OLEDs). The theoretical calculations along with the photophysical characterization studies suggest the coexistence of the monomer and dimer species at high concentration of compound 1. The presence of this type of dimer (formed via H-bonding) is responsible for the increased emission. However, the most notable feature is the 3D network of vastly interconnected fibers formed in the organogel that modifies the photophysical properties. Based on this, several OLED architectures are made in order to understand the mechanism involved in the electroluminescence (EL) behavior of 1. Although the position of the EL spectra differs from that of the photoluminescence (PL) spectra, the trends observed in the device properties perfectly match with dimer formation. In this framework a better device performance is associated to a higher efficiency of dimer formation, which optimizes in the OLED prepared from the organogel. Therefore, these results show that the rational combination of a moiety showing a strong PL intensity increased upon aggregation with organogel properties is an efficient strategy to create alternative emitters for OLED devices., This work was financially supported by the MICINN and Ministry of Economy and Competitiveness of Spain through projects (CTQ2013‐40562‐R, CTQ2014‐56422‐P). C. Martín thanks the Research Foundation‐Flanders for her postdoctoral fellowship. G.M. thanks the Ministry of Economy and Competitiveness for a “Ramón y Cajal” contract (RYC‐2013‐12772). The authors are also indebted to Belspo program through IAP VI/27 and VII/05 and to the KULeuven Research Fund through GOA 2011/3 and C14/15/053. The authors gratefully acknowledge financial support from the European Union's Seventh Framework Programme (FP7/2007‐2013 under grant agreement no. 310651 SACS).

The electronic and photophysical properties of 6,11-dihydro-5H-diindolo[2, 3-a:2′,3′-c]carbazole, an asymmetric cyclic dehydrotrimer of indole, have been explored and compared to its symmetric analogue, 10,15-dihydro-5H- diindolo[3,2-a:3′,2′-c]carbazole (triindole), a well-known high hole mobility semiconductor. To this purpose, we use a joint experimental and theoretical approach that combines absorption and emission spectroscopies, cyclic voltammetry, and spectroelectrochemistry with DFT calculations. Lowering the symmetry of the triindole platform causes a red-shift of the absorption edge and emission maxima and improved the fluorescence quantum yield. Cyclic voltammetry and spectroelectrochemistry reveal the reversible nature of the two observable oxidation processes in the alkylated asymmetric triindoles together with an increase in the stabillity of their oxidized species. On the other hand, the insertion of alkyl groups on the nitrogen atoms results in a further fluorescence enhancement although larger reorganization energies are found. DFT and time-dependent (TD-DFT) calculations successfully support the experimental data and aid in the understanding of the tuning of the physicochemical properties of the triindole platform upon symmetry lowering toward their incorporation in electronic devices. © 2014 American Chemical Society., This work was financially supported by the MICINN of Spain (CTQ2010-18813) and the CAM (Project S2009/MAT-1756/CAM), MINECO of Spain (CTQ2012-33733), Junta de Andalucía (P09-FQM-4708). M.C.R.D. thanks the MICINN for a “Ramón y Cajal” Research contract. D.A.S.F. gratefully acknowledges the financial support from the Brazilian Research Councils CNPq CAPES, CNPq (grant 303084/2010-3) and FAP-DF (Fundaçâo de Apoio à Pesquisa do Distrito Federal).

A new kind of low molecular-mass organic gelator (LMOG) π-electron-deficient N,N-octyl-7,7′-diazaisoindigo (1) with aggregation-induced enhanced emission (AIEE) phenomenon is described. This organogel is capable of self-assembling through intermolecular H-bonding and π-π interactions between diazaisoindigo molecules. Its rheological properties, X-ray diffraction pattern, optical properties and theoretical calculations were investigated. The AIEE effect is exhibited in fluorescence during the formation of the supramolecular organogel, which persisted in the xerogel state, and the spectral red-shifts suggest the formation of J-type aggregates during the gelation process via π-π interactions in microbelts or 3D networks. Fluorescence lifetime and quantum yield significantly increase from dilute solution to the aggregate state. From a theoretical perspective, the effect of the aggregation of 1 on the photophysical properties was also studied by means of the density functional theory (DFT). In this sense, the lowest energy electronic transitions were calculated for both the single molecule and different size aggregates in order to predict spectral shifts. In addition, the geometry and molecular properties of the excited state were analyzed in different material states., This work was financially supported by the MICINN of Spain (Grant CTQ2013-40562-R), by Consejería de Economia y Conocimiento, Junta de Andalucía (Grant FQM-337), Consejería de Educación y Ciencia de la Junta de Comunidades de Castilla-La Mancha (Project PEII11-0279-8538), and Diputación de Albacete (DIPUAB-16-GARZONRUIZ). The authors thank Centro de Servicios de Informática y Redes de Comunicaciones (CSIRC), Universidad de Granada (Spain),and Servicio de Supercomputación de la Universidad de Castilla-La Mancha for providing the omputing time. J.P. thanks Dr. M. Ramírez for his help in the PXRD pattern representation and interpretation and E. Rodríguez and P. Ciriafor their support. The authors thank Prof. J. Reimers, University of Technology Sydney, for allowing us to use the DUSHIN program.

The p-type semiconducting properties of a triphenylene-fused triindole mesogen, have been studied by applying two complementary methods which have different alignment requirements. The attachment of only three flexible alkyl chains to the nitrogen atoms of this π-extended core is sufficient to induce columnar mesomorphism. High hole mobility values (0.65 cm V s) have been estimated by space-charge limited current (SCLC) measurements in a diode-like structure which are easily prepared from the melt, rendering this material a good candidate for OPVs and OLEDs devices. The mobility predicted theoretically via a hole-hopping mechanism is in very good agreement with the experimental values determined at the SCLC regime. On the other hand the hole mobility determined on solution processed thin film transistors (OFETs) is significantly lower, which can be rationalized by the high tendency of these large molecules to align on surfaces with their extended π-conjugated core parallel to the substrate as demonstrated by SERS. Despite the differences obtained with the two methods, the acceptable performance found on OFETs fabricated by simple drop-casting processing of such an enlarged aromatic core is remarkable and suggests facile hopping between neighboring molecular columns owing to the large conducting/isolating ratio found in this discotic compound.

In this paper, a new family of 7,7′-diazaisoindigo molecules was synthesized and the electronic properties of these materials were studied by theoretical calculations and photophysical studies. Density functional theory (DFT) calculations at the B3LYP/6-311+G∗∗ level of theory demonstrate that the diaza-substitution clearly imposes a higher planarity in these molecules compared to the isoindigo counterparts. This effect is ascribed to an electrostatic attraction between the carbonyl group and the H atom at position 4. The isodensity surfaces and energies of the frontier molecular orbitals (HOMO and LUMO) calculated at the B3LYP/6-311++G(2d,p) level of theory show a stabilization (∼0.35 eV) of both orbitals in the 7,7′-diazaisoindigo derivatives compared to isoindigo and also the intramolecular charge-transfer character for the HOMO → LUMO transition, as it occurs in isoindigo. Photophysical studies were carried out using steady-state and time-resolved picosecond fluorescence techniques. The emission spectra show a red-shift of the peak upon increasing the polarity of the solvents which confirms the charge-transfer character of this transition. Moreover, the intensity of the emission peak decreases with the solvent polarity and increases in viscous solvents, which is tentatively attributed to a non-radiative deactivation pathway connected with a torsion of the central ethylene bond. The time-resolved emission technique shows shorter fluorescence lifetimes with increasing polarity of the solvents, in line with the stronger quenching of the fluorescence signal. The appearance of fluorescence peaks and relatively long fluorescence lifetimes in the 7,7′-diazaisoindigo derivatives compared to the non-fluorescent isoindigo counterpart are ascribed to the fine adjustment of the orbital energies through the aza insertion in the isoindigo core structure. This is a consequence of the slower non-radiative process in 7,7′-diazaisoindigo which may help to promote the use of this building block instead of isoindigo in organic electronics., This work was financially supported by the MICINN of Spain (CTQ2013-40562-R). G. M. thanks the Ministry of Economy and Competitiveness for a “Ramón y Cajal” contract (RYC-2013-12772). G. M. and L. C. acknowledge the Ministry of Economy and Competitiveness for financial support (CTQ2014-56422-P).

A set of chiral discotic phenylacetylenes have been synthesized by 3-fold Sonogashira coupling between different ethynylbenzenes and triiodobenzenes. The resultant bulk materials are fully characterized by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction. The octopolar nature of the target compounds is studied by UV-vis absorption spectroscopy and hyper-Raleigh scattering in solution. Optimization of the donor-acceptor substitution yields both high hyperpolarizability values and appreciable mesomorphic properties. A simple thin film device for second harmonic generation has been prepared from the nitro-substituted liquid crystalline derivative.

Chemists worldwide are making strong efforts toward finding an organic semiconductor with optimum charge-transport stability and processability properties, approaching the problem from several angles. The number and variety of organic semiconductors have expanded exponentially during the past few years, allowing their classification and identification of the advantages and drawbacks of the different candidates, and leading to an increasingly better understanding of factors affecting charge carrier mobility. In this Perspective, we present different types of materials available, classified according to their supramolecular order. As it will be shown, high intermolecular order, although beneficial for charge transport, may compromise processability. The required balance between processing and high mobility can be achieved only through an adequate design at both the molecular and supramolecular levels.

PbII ethynyl- and butadiynyl-bridged bis(phthalocyaninates) 1a–d, peripherally functionalized with n-butoxy moieties, have been synthesized by using Pd-catalyzed cross-coupling methodologies. Preliminary open-aperture Z-scan experiments with nanosecond pulses at 550 nm on solutions of PbII bis(phthalocyaninates) 1b and 1d show strong reduction of the transmission at high intensities, although an irreversible optical behaviour is observed at the experimental time scale. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

We report on a new p-type organic semiconductor single crystal, 5,10,15-trimethyl-10,15-dihydro-5H-diindolo[3,2-a:3’,2’-c]carbazole (N-trimethyltriindole). This molecule crystallizes forming a highly ordered columnar structure in which stacked molecules are situated at two alternating distances (3.53 A and 3.68 A) along the column as determined by single crystal X-ray diffraction analysis. These short intermolecular distances between adjacent units, make this system an ideal candidate for charge-transport processes along the stacks. Relevant parameters for transport (i.e. internal reorganization energies, transfer integral) have been estimated by DFT calculations at a 6-311G(d,p)/B3LYP level of theory. As a double check for the transfer integral, the electronic band structure of a one-dimensional stack of molecules has been computed. The electronic properties of this material have been studied both theoretically and experimentally. Its HOMO value is found to coincide with Au work function (ΦAu = 5.1 eV), thus low barriers are expected for hole injection from gold electrodes. The hole mobility of this material has been predicted theoretically considering a hopping-type mechanism for the charge-transport and determined experimentally at the space charge limited current (SCLC) regime of the current–voltage measurements. Both theoretical and experimental values are in good agreement. The high hole mobility (μmin = 0.4 cm2 V−1 s−1) of this material points towards its useful application in the organic electronics arena. N-Trimethyltriindole single crystals constitute an essential model to study transport properties of triindole-based materials and to design new derivatives with improved electronic performance.

Two functionalized phthalocyanine-based chromophore systems having two iodophthalocyaninatozinc(II) rings bound together through a butadiynyl linkage 1a,b have been synthesized by oxidative Eglinton coupling of the corresponding monomer, and fully characterized. The electronic characteristics of these extensively linearly pi-conjugated compounds were modulated by the introduction of different peripheral substituents into the phthalocyanine moieties and investigated by UV-visible spectroscopy. The reactivity of the two iodo substituents was explored to prepare a novel bisphthalocyanine containing two ethynylphenyl moieties, thus pointing out the possibility of incorporating other electro and/or photoactive moieties in the BisPc system, taking advantage of the iodo-functionalization.

A new self-assembled organogel based on 5-(4-nonylphenyl)-7-azaindole (1), possessing an aggregation-induced emission phenomenon (AIE), is described. The incorporation of phenyl alkyl chains improves processability of the platform to form a new class of gelator. The fluorescence spectrum of 1 suffers changes in the gelation process, and an AIE phenomenon is observed during the phase transition from sol to gel state. The fluorescence is decreased slowly by heating the gel, and no emission is detected in concentrated solutions of 1. The AIE effect is due to the formation of the supramolecular organogel, where a self-association of the 7-azaindole moieties by dual hydrogen-bonded dimers is present. Regarding the solid-state emission properties, the xerogel 1 exhibits blue emission as well as in its organogel form. Therefore, it could be considered as a promising blue emitter in the solid state., This work was fi nancially supported by the MICINN of Spain (CTQ2013-40562-R) and CAM (Project S2013/MIT-2740). Thanks to Dr. Perles (SIdI, UAM) for resolution of single- crystal X-ray di ff raction analysis and M. Dolores Penin and Antonio Almorin (SIdI, UAM) for 2D NMR studies. Thanks to Dr. Gonza lez-Rodri guez for technical support

For the first time, symmetrical and unsymmetrical π-electron-conjugated trinuclear phthalocyanines (Pcs) were synthesized with the Pc units connected directly by ethynyl linkages. Symmetrically alkoxy-substituted bridged ethynylphthalocyaninatozinc(II) triad was prepared by direct Sonogashira cross-coupling reaction between suitable diiodo Pc and alkynyl Pc derivatives. Nevertheless, the synthesis of the Pc-based triad having a donor-acceptor electron character was carried out by means of co-cyclo-tetramerization of two different phthalonitriles, namely 4,5-bis(pro-pylsulfonyl)phthalonitrile and 4,5-[hexa(butoxy)ethynylphthalocyaninatozinc(II)]phthalonitrile in the presence of a cobalt(II) salt.

Four phthalocyanine-based compounds with pseudo D3h symmetry have been synthesised and fully characterised. Palladium cross-coupling methodologies were employed in order to synthesise 1,3,5-tris[(phthalocyaninyl)ethenyl]benzene (Heck) and 1,3,5-tris[(phthalocyaninyl)ethynyl]benzene (Sonogashira) derivatives. Knoevenagel condensation conditions were then applied to the synthesis of 1,3,5-tris[cyano(phthalocyaninyl)ethenyl]benzene and 2,4,6-tris[(phthalocyaninyl)ethenyl]-1,3,5-triazine. Preliminary second-order nonlinear optical studies, by hyper-Rayleigh scattering measurements, revealed that the compounds containing ethenyl linkers induce a strong octupolar effect while the ethynyl-containing compound does not show any octupolar enhancement. The introduction of a triazine central core does not modify significantly the nonlinear optical behaviour of the compound. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

One of the key issues in the development of efficient optical limiters is the search for appropriate materials with improved nonlinear absorption. Phthalocyanine materials are among the most promising nonlinear absorbers described in the literature. Ethynyl and butadiynyl-bridged bisphthalocyanines and related ethynyl-containing mononuclear compounds have been synthesized and experimentally studied using the z-scan technique with nanosecond pulses at 532 nm. We intend to ascertain the effect of the electronic interaction between macrocycles in the optical limiting performance of phthalocyanines.

Cyclooligomeric phthalocyanines with the special feature of having a dehydroannulene core are described. Compounds 4a,b and 5a,b were prepared by an oxidative coupling mediated by copper from the corresponding diethynyl unsymmetrically substituted phthalocyanines 8a,b, which are easily accessible from the corresponding diiodo compounds 6a,b by a palladium-copper-catalyzed coupling. Appropriate conditions to selectively form cyclodimers and cyclotrimers using Glaser and Eglinton methodologies have been attempted. In this way, two compounds, 4a and 5b, each representative of a kind of oligomers, could be appropriately isolated and characterized by MALDI-MS. The UV-vis spectra of compounds 4a and 5b show a split Q-band shifted to the red with respect to the corresponding precursor 8a,b. This can be interpreted, in light of previous results, as a consequence of intramolecular electronic coupling between the Pc subunits. Extensive formation of aggregates in chloroform can be also inferred from the spectra. No significant differences could be observed in the spectra by comparison with that of the open-chain analogue 11, most probably due to a saturation phenomenon of the optical properties already pointed out in the literature for other alkynyl-linked open-chain dimers.

Two families of "push-pull" phthalocyanines 1-3 having an unusually strong dipole moment have been prepared. The syntheses of unsymmetrically substituted phthalocyanines 1a,b and 2 bearing one or two electron-withdrawing 4-nitrophenylethynyl moieties, respectively, and six alkoxy substituents were performed by combination of a zinc or nickel templated cyclotetramerization and cross-coupling palladium mediated methodologies. In a similar way, the "push-pull" compounds 3a,b having a reversal substitution pattern, characterized by the presence of one electron-donor 4-(dimethylamino)phenylethynyl unit and six strong acceptor alkylsulfonyl substituents were prepared. The compounds show very large second-order nonlinear optical responses.

A new class of conducting discotic liquid crystals is identified in recently synthesized derivatives of heptacyclic triindole, which combine the hole transport properties of the carbazole unit with...

1D π-conjugated organic micro- or nanostructures keep all the advantages found in organic single crystals, e.g. high crystallinity, but without the tricky growth associated with large-sized crystals. They also present low-cost processing, solution processable materials, and large-area fabrication, and are compatible with flexible substrates. Electronic and optical properties of 1D π-conjugated organic micro- and nanomaterials can be tuned by changing their size at the central core or chemical modification of the aromatic substituents, among other alternatives. Current challenges are to find and develop an accurate control of the morphology, size, degree of uniformity, and alignment of the micro- and nanometer-sized organic single crystals, for future applications in miniaturized devices. © 2013 The Royal Society of Chemistry., Financial support from the MEC CTQ2010-18813 and the CAM (Project S2009/MAT-1756/CAM) is gratefully acknowledged.

et al., We report the synthesis, mesomorphic behavior, and mobility values of a series of highly ordered N-substituted triindole-based columnar liquid crystals. Shortening the length of N-alkylic substituents from N-dodecyl to N-methyl chains results in a drastic approach of the disks within the columns and in an impressive increase in charge carrier mobility. An study of aggregation in solution provide insights into the intermolecular forces responsible of the reduction of the intrastack distance as the size of the N-alkyl chains is decreased and offer evidence of stabilization of the columns by the contribution of cooperative CH−π interactions. The materials presented here exhibit mobility values, even in totally misaligned columnar phases, that may compete with those of the best polycrystalline organic semiconductors, without the need of costly vacuum evaporation processes., Support by Comunidad Autónoma de Madrid under project S2009/MAT-1756 and by Ministerio de Ciencia e Innovación (Spain) under projects CTQ2010-18813, CTQ2009-09030/BQU, MAT2011-27978-C02-01 are gratefully acknowledged.

We present a series of differently substituted star-shaped hexaaryltriindoles with tunable light-emitting properties. The deep blue emission is unchanged by donor peripheral substituents while an increasing acceptor character produces a reduction of the optical gap, an increased Stokes shift and eventually leads to the appearance of a new electronic level and to the simultaneous deep blue (413 nm) and green (552 nm) emission in solution. Quenching by concentration increases with the acceptor character but is lower as the tendency of these compounds to aggregate is stronger. Solution processed thin films present optical and morphological qualities adequate for device fabrication and similar electronic structure compared to solutions with an emission range from 423 nm up to 657 nm (red), demonstrating the possibility of tuning the energy levels by chemical functionalization. We have fabricated and characterized single-layer solution processed organic light emitting diodes (OLED) to investigate the influence on transport and emission properties of the substituting species. We analyzed the I-V response using a single-carrier numerical model that includes injection barriers and non-uniform electric-field across the layer. As a result, we obtained the electric field dependence of the mobility for each device. Best results are obtained on the most electron rich derivative functionalized with six donor methoxy groups. This material shows the highest emission efficiency in solid state, due to aggregation-induced enhancement, and better transport properties with the highest mobility and a very low turn-on voltage of 2.8 V. The solution processed OLED devices produce stable deep blue (CIE coordinates (0.16, 0.16)) to white (CIE coordinates (0.33, 0.3)) emission with similar luminous efficiencies. © 2012 Elsevier B.V. All rights reserved., Support by Comunidad Autónoma de Madrid under project S2009/MAT-1756 and by Ministerio de Ciencia e Innovación (Spain) under projects MAT2009-08786, CTQ2010-18813, TEC2009-13991-C02-02 and TEC2011-13635-E are gratefully acknowledged.

A new carbazole-related small molecule exhibiting self-assembly into ordered nanostructures in solution-processed cast films has been synthesized and its charge-photogeneration and -transport properties have been investigated. Large photoconductivity was measured in the amorphous state while an enormous improvement in the photoconduction properties was observed when the molecules spontaneously organized. Photocurrents increased upon self-assembly by up to four orders of magnitude, mostly due to the drastic enhancement of the charge photogeneration. A greatly favorable arrangement of the aromatic cores in the resulting nanostructures, which were characterized by X-ray analysis, may explain these improvements. Photocurrents of mA cm−2, on/off ratios of 104 and quantum efficiencies of unity at low field and light intensity, which are among the best values reported to date, along with the simplicity of fabrication, give this readily-available organic system great potential for use in plastic optoelectronic devices.

The stacking order and distance in columnar phases of triindole-based liquid crystals is controlled by an ethynyl linker (see picture; orange rod) between the central triindole core (green) and the peripheral flexible chains of a discotic mesogen. Hole (h) mobility is very high even if the stacking distances is not very short and the conjugated system is not particularly extended., This work has been supported by CTQ2007-65683/BQU, (CTQ2009- 09030), S2009/MAT-1756/CAM, MiUR through the PRIN 2007 (2007WJMF2W) project, Gobierno de Aragón, 200960I086 PIE.

New π-extended discotic liquid crystals based on heptacyclic triindole have been synthesized and their mesomorphic behaviour investigated. The synthesis of π-extended compounds was carried out by oxidative cyclodehydrogenation of differently substituted star-shaped hexaaryltriindoles to afford the planar derivatives with an extended core. Extending the conjugation in these materials results in a significant increase in the order and range of the mesophases. The influence of the peripherally attached groups in the mesomorphic and electronic properties offers a great opportunity to further tune the properties of these compounds intended to their incorporation in devices. © 2011 The Royal Society of Chemistry., Financial support from the MEC CTQ 2009-09030, CTQ2010- 18813 and the CAM (Project S2009/MAT-1756/CAM), is gratefully acknowledged.

A new carbazole-related small molecule exhibiting self-assembly into ordered nanostructures in solution-processed cast films has been synthesized and its charge-photogeneration and -transport properties have been investigated. Large photoconductivity was measured in the amorphous state while an enormous improvement in the photoconduction properties was observed when the molecules spontaneously organized. Photocurrents increased upon self-assembly by up to four orders of magnitude, mostly due to the drastic enhancement of the charge photogeneration. A greatly favorable arrangement of the aromatic cores in the resulting nanostructures, which were characterized by X-ray analysis, may explain these improvements. Photocurrents of mA cm-2, on/off ratios of 104 and quantum efficiencies of unity at low field and light intensity, which are among the best values reported to date, along with the simplicity of fabrication, give this readily-available organic system great potential for use in plastic optoelectronic devices. Large photoconduction enhancement from small molecules: A new carbazole-related small molecule exhibiting self-assembly into ordered nanostructures in solution-processed cast films has been synthesized and its charge-photogeneration and -transport properties have been investigated. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim., This work was supported by MAT2005-07369-C03, CTQ2007-65683/BQU, MAT2008-06648-C02-01 and S2009/MAT-1756/CAM). F.G.G. thanks the program Juan de la Cierva of the Spanish Government MEC (grant JCI-2006-3029-2615). E.M.G.F. thanks the Consejo Superior de Investigaciones Cientificas (Program I3P) for a postdoctoral contract.

Two families of “push−pull” phthalocyanines 1−3 having an unusually strong dipole moment have been prepared. The syntheses of unsymmetrically substituted phthalocyanines 1a,b and 2 bearing one or two electron-withdrawing 4-nitrophenylethynyl moieties, respectively, and six alkoxy substituents were performed by combination of a zinc or nickel templated cyclotetramerization and cross-coupling palladium mediated methodologies. In a similar way, the “push−pull” compounds 3a,b having a reversal substitution pattern, characterized by the presence of one electron-donor 4-(dimethylamino)phenylethynyl unit and six strong acceptor alkylsulfonyl substituents were prepared. The compounds show very large second-order nonlinear optical responses.

The synthesis and aggregation properties of a series of differently substituted star-shaped hexaaryltriindoles both in solution and in the solid state are being reported. While these molecules do not show any significant intermolecular aggregation in CDCl(3), it has been possible to induce aggregation by increasing the polarity of the solvent and therefore facilitating the occurrence of solvophobic forces. A study of the influence of the electronic character of peripheral substituents on the self-association behavior in solution has shown that increasing the electron-donor character of the substituents facilitates self-association while derivatives substituted with electron-acceptor substituents do not self-assemble. The electronic nature of the substituents also has an influence in the geometry of the stacking of these derivatives observed in the solid state. While unsubstituted hexaphenyl triindole self-assemble in a staggered face-to-face arrangement, attaching six cyano functional groups results in an offset stacking. The influence of the substituents in the strength and geometry of the stacking tendency contrasts with the trend expected for an aggregation induced solely by pi-pi interactions, but can be explained considering an important contribution of multiple cooperative CH-pi interactions.

Trabajo presentado como comunicación al "IX Organic Field-Effect Transistors" celebrado en San Diego (USA) en Agosto del 2010., We introduce a new family of stable high-mobility organic π-type semiconductors based on the electron-rich 10,15- dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (triindole) extended π-conjugated system. This platform tends to form columnar stacks of the aromatic cores maximizing π-orbital overlap between adjacent molecules, thus paving the way for the one-dimensional migration of charge carriers along the columns. In addition these compounds have two different types of positions that can be functionalized independently offering the possibility of tuning their electronic properties as well as their morphology through chemical functionalization. The integration of the optimized triindole derivatives into solution processed devices as active layer is explored in this work., Financial support from the MEC (CTQ2007-65683/BQU and S2009/MAT-1756/CAM are gratefully acknowledged.

Much effort is being dedicated to develop small organic molecules for their use in organic electronic devices, for which a key parameter is the mobility of charge within the active organic layers. Important advances achieved in this field have been therefore connected to the enhancement of the charge carrier mobility of organic semiconductors. In this communication we present a new family of stable high-mobility organic p-type semiconductors based on the electronrich 10,15-dihydro- 5H -diindolo[3,2-a:3',2'-c]carbazole (triindole) platform. We show how it is possible to tune their electronic properties as well as their supramolecular organization through chemical functionalization.

A new series of C3-symmetrical N-(hetero)arylmethyl triindoles has been synthesized in a straightforward procedure. The structure and conformation in the solid state have been determined for three derivatives (3, 4, and 6) by X-ray crystallographic analysis. In all three cases, the molecules adopt a tripodal conformation with all of the flexible arms directed towards the same side, thereby delimiting an inner cavity. Compound 6 crystallizes and forms C3-symmetric dimeric cage-like complexes. Guest molecules of chloroform and water are confined within the resulting cavities with stabilization by different intermolecular interactions; this highlights the potential of these compounds in the construction of supramolecular systems. A computational analysis has been performed to predict the most stable conformers. As a general trend, a preference for a conformation with all branches directed to the same side has been predicted. Comparison between theoretical and experimental results indicates that the computational level selected for the present study, B3LYP/6-31G*, is able to reproduce both the minimum energy conformations and the rotation barriers about the N-CH2 bond. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.