2,6,10-Tris(bithiophenyl)triphenylene: Synthesis and high-spin alignment in its p-doped radical derivative

2,6,10-Tris[5′-(5-hexyloxyphenyl-2,2′-bithiophenyl)]-3,7,11-tris(hexyloxy)tripheneylene (2) was designed and synthesized as a π-conjugated platform to produce its tris(cationic radical) derivative (1) in a non-Kekulé and nondisjoint fashion. An electrochemical study revealed the chemically reversible redox property of 2. Gaseous antimony pentachloride-doping of 2 dispersed in a polystyrene matrix gave its cationic radical. It was chemically stable with a half-life >2 weeks and displayed a triplet ground state based on an ESR measurement. A high-spin state with S = 3/2 for 1 was proved by the magnetization and magnetic susceptibility.     

Synthesis and characterization of two-armed poly(ɛ-caprolactone) polymers initiated by the Schiff's base complexes of copper(II) and nickel(II)

Two-armed poly(?-caprolactone) (TAPCL) polymers were successfully synthesized via the ring opening polymerization (ROP) of ?-caprolactone (?-CL) using the Schiff's base complexes [Cu(SAEE)₂] (1) and [Ni(SAEE)₂] (2), which have two hydroxyl functional groups, as the two-site initiators and tin(II) 2-ethylhexanoate (Sn(Oct)₂) as the catalyst in bulk at 115 °C. The Schiff's base complexes (1 and 2) were synthesized by utilizing the concentrated template synthesis method starting from salicyl aldehyde, 2-(2-aminoethoxy) ethanol and related metal acetate salts. The synthesized TAPCL polymers were characterized by GPC, FTIR, UV–vis, and electron paramagnetic resonance (EPR). The molecular weights of TAPCL polymers linearly increased with increasing molar ratio of the monomer to the initiator. The results obtained from FTIR, UV–vis, and EPR studies indicated that TAPCL polymers had the Schiff's base complexes at the junction point of PCL arms. The crystallization behavior of TAPCL was studied by using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Thermal behavior of TAPCL was also investigated by thermogravimetrical analysis (TGA).     

Preparation of silver nanostructure from silver(I) coordination polymer and fabrication of nano silver(I) bromide by reverse micelles technique

A new one-dimensional silver(I) coordination polymer, [Ag(μ-bpfb)(NO₃)]_n (1); bpfb = N,N′-bis(4-pyridylformamide)-1,4-benzene, has been synthesized and characterized by IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X-ray data show that the silver(I) 1D coordination polymer grows into a three-dimensional network by hydrogen bonding and π–π stacking interactions. Compound 1 with nanorod morphology was also prepared by sonochemical method. The cetyltrimethylammonium bromide (CTAB) as a cationic surfactant was used in reverse micelles technique to obtain spongy silver(I) bromide nanoparticles from compound 1. Also, different silver nanoparticles have been prepared via direct calcination at 673 K and thermal decomposition in oleic acid from compound 1. The nanostructures of [Ag(μ-bpfb)(NO₃)]_n (1), silver and silver(I) bromide were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDAX) analysis. Thermal stability of compound 1 in both bulk and nano-sized form was studied by thermal gravimetric (TG) and differential thermal (DT) analyses.     

Highly conjugated acrylate-functionalized polythiophenes from anodic coupling of thiophene- and bithiophene-hexyl acrylates

Anodic coupling of thiophene- (1) and cyclopentadithiophene- (2) hexyl acrylates in acetonitrile to polythiophenes is reported. The resulting polymers have been characterized by cyclic voltammetry, UV–vis and FTIR spectroscopy and in-situ conductivity. The produced polythiophene films, for which FTIR analysis show that the acrylate moiety is kept unchanged, display high conjugation lengths (λ_max=520 (1) and 600 (2) nm) and conductivities (20 (1) and 100 (2) S cm⁻¹).     

Synthesis and properties of μ-cyano(phthalocyaninato)-rhodium(III)

This contribution reports on the synthesis of μ-cyano(phthalocyaninato)rhodium(III), [PcRhCN]_n (1), by splitting off potassium cyanide from potassium(dicyano)phthalocyaninatorhodium(III), K[PcRh(CN)₂] (2). Monomeric complexes, PcRh(L)CN (7), were formed when [PcRhCN]_n (1) was treated with base molecules L, such as n-butylamine and pyridine. All compounds were characterized by IR, far-IR spectroscopy, thermal and elemental analyses, and partly by UV, ¹H-NMR and FD (field desorption) mass spectroscopy. The undoped polymer [PcRhCN]_n (1) exhibits a d.c. dark conductivity of 4 × 10^?4 S/cm, which was diminished by eight orders of magnitude when the polymeric structure was decomposed by treatment with a competing ligand.     

Synthesis of a boron-containing conducting polymer from the anodic oxidation of Tris(pyrrolyl)borane

The electrochemical oxidation of Tris(N-pyrrolyl)borane (1) in THF yielded a conducting polymer film with an electron conductivity of ca. 7×10⁻⁴ S cm⁻¹. The coulometric measurements indicated that the three pyrrolyl units were not totally coupled during the electropolymerization reaction. From further UV–VIS and FT-IR spectroscopy data, a structure of poly(1) was then proposed.     

Synthesis and third-order NLO properties in LB films of triazolehemiporphyrazines

Langmuir-Blodgett (LB) films of free and cobalt(II)-metallated triazolehemiporphyrazines (2–4), including some new synthesized compounds (3–4), have been prepared and characterized. All investigated molecules adopt an edge-on arrangement in the film as previously found for the structurally related phthalocyanines (Pcs). The real and imaginary parts of the third-harmonic susceptibility χ⁽³⁾ (3ω:ω,ω,ω) have been measured at 1.06 μm fundamental wavelength. Values are similar to those obtained for LB films of Pcs. No significant effects associated with cobalt metallation have been found at variance with previous results in solution at λ = 1.3 and λ = 1.9 μm.     

Synthesis,spectroscopy and electroluminescence of cadmium(II) polypyridyl complexes

Five new complexes [Cd(ptpy-R)₂](PF₆)₂ (ptpy = 4′-phenyl-2,2′:6′,2″-terpyridine; R = tert-Butyl (1), hexyloxy (2), carbozole-9-yl (3), naphthalene-1-yl-phenylamine-N-yl (4) and diphenylamine-N-yl (5)) were synthesized and characterized by ¹H NMR, elemental analyses, UV–vis spectroscopy and cyclic voltammetry. The emission color of resultant complex molecules has been tuned effectively, from violet (397 nm) for 1 to orange (602 nm) for 5 in film, by modifying the electron-donating ability of the substituent R. The UV–vis spectroscopy and the solution-state luminescence showing remarkable solvatochromism suggests the emission involves the intra-ligand charge transfer (¹ILCT) excited state, occurring from the substituent R moiety to Cd(II) coordinated terpyridine. The electroluminescence (EL) properties for these organic materials were also studied and complexes 3, 4 and 5 exhibit EL wavelength at 548 nm, 596 nm and 604 nm with maximum current efficiency of 3.25 cd/A, 3.15 cd/A and 2.16 cd/A, respectively.     

Photoactive ionic assemblies between n dopable perylene and p dopable carbazole derivatives

The study of molecular assemblies obtained by ionic interactions between two π-conjugated organic molecules one possessing electron donor properties and the other possessing electron acceptor properties is discussed here.The electron acceptor molecules chosen are two tetra-chlorinated 3,4,9,10-perylene tetracarboxylic diimides bearing pyridine or amine functions ((1) or (2)) and the electron donor is 4-carbazol-9-yl-butane-1-sulfonic acid (3). The electrochemical characterizations and UV–vis/photoluminescence spectroscopy studies of each compound were realized. Moreover, photoluminescence quenching of (1) and (2) solutions is observed when they are protonated with the acid function of (3). Interestingly, with a simple mixture of (1) or (2) with 9-ethyl-carbazole, (1) and (2) solutions fluorescence quenching is very low. Finally, the relative energy levels values of the HOMO and LUMO of (1)–(3) were estimated and the results are compatible with a possible electron transfer from carbazole to perylene unit making these ionic assemblies attractive candidate for an active layer application in solar cell devices.     

Preparation of TiO2/PANI composites in the presence of surfactants and investigation of electrical properties

“In situ” polymerization was carried out in the presence of titanium dioxide (TiO₂) to synthesize TiO₂/polyaniline (TiO₂/PANI) composite in an aqueous medium containing anionic (sodium dodecylbenzenesulfonate), DBSNa, cationic (tetradecyltrimethylammonium bromide), TTAB, and nonionic surfactants (poly(ethylene oxide) (20) sorbitan monolaurate), Tween 20). The composites were characterized by FTIR, UV–vis spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Gouy balance measurements. The FTIR and UV–vis spectra reveal that the interaction between TiO₂/PANI composite and surfactants. The anionic and cationic surfactants incorporated with TiO₂/PANI composite structure. The stability of the composites in terms of direct-current electrical conductivity retention was studied in isothermal conditions. Electrical conductivity measurements indicate that the conductivity of TiO₂/PANI synthesized in the presence of the cationic surfactant has the highest conductivity value. All composites showed negative mass magnetic susceptibility values.     

Light stability of 3,4-ethylenedioxythiophene-based derivatives

The light stability of two 3,4-ethylenedioxythiophene-based derivatives, i.e. the oligomeric compound 5,5″-diphenyl-2,2′-5′,2″-ter(3,4-ethylenedioxythiophene) (1, 3-EDT) and the corresponding polymer of 2-tetradecyl-2,3-dihydro-thieno[3,4-b][1,4]dioxine (2, PEDT-C14), was investigated. Their stability upon irradiation with a xenon lamp was studied by means of UV-Vis spectroscopy. These measurements lead to the proposal of a photooxidation mechanism that seems to be operative in chlorinated solvents, followed by H-abstraction. Furthermore, the experiments point out that it is mainly UV light that causes the instability of the oxidatively doped compounds.     

Synthesis and electrochemical,in situ spectroelectrochemical,electrical and gas sensing properties of ball-type homo- and hetero-dinuclear phthalocyanines with four [1a,8b-dihydronaphtho[b]naphthofuro[3,2-d]furan-7,10-diyl] bridges

The new mono-nuclear Fe^II 2 and ball-type homo-dinuclear Fe^II–Fe^II 3 phthalocyanines have been synthesized from the corresponding 4,4′-(1a,8b-dihydronaphtho[b]naphthofuro[3,2-d]-furan-7,10-diyl)bis(oxy)diphthalonitrile 1 while ball-type hetero-dinuclear Fe^II–Co^II phthalocyanine 4 was synthesized from 2. The compounds have been characterized by elemental analysis, UV–vis, IR and MALDI-TOF-mass spectroscopies. The redox behaviours of the complexes were identified by controlled-potential coulometry, cyclic voltammetry and differential pulse voltammetry measurements on Pt in dimethylsulfoxide containing tetrabutylammonium perchlorate. The assignments of the redox processes and the understanding of the interactions between the metal phthalocyanine units in 3 and 4 were achieved by the combined evaluation of the voltammetric and in situ spectroelectrochemical outcomes. Complex 3 showed ring-based mixed-valence behaviour as a result of the considerable interaction between the phthalocyanine rings. On the other hand, the interactions between the two metal phthalocyanine units of 4 were found to be much weaker than those in 3. The potential application of molecular organic semiconductors needs the control adjustment of conductivity. Ac and dc conductivity measurements were performed with the applied external electric filed. At high frequency, the conduction follows the universal power law and conduction mechanism can be explained by classical hopping barriers mechanism for the system.     

Magnetic Langmuir–Blodgett films of ferritin with different iron loadings

Magnetic Langmuir–Blodgett multilayers of two ferritin molecules 1 and 2, containing, respectively, 4220 and 3062 Fe atoms have been prepared by using the adsorption properties of a 6/1 mixed monolayer of dioctadecyldimethylammonium bromide (DODABr) and methyl stearate (SME). Transfer ratios close to unity were reached giving rise to LB films with a strong red colour. Infrared and UV–vis spectroscopy indicates that ferritin molecules are incorporated within the LB films. Magnetic measurements show that the superparamagnetic properties of these molecules are preserved. Thus, a marked hysteresis loop of magnetisation is obtained for LB films of 1 and 2 with a coercive field of 3400 and 2400 G, respectively.     

Synthesis,electrochemistry, spectroelectrochemistry and electrocolorimetry of phthalocyanine–anthraquinone hybrids

The tetra substituted metallophthalocyanines 2 and 3, soluble in common organic solvents, bearing four 2-(9,10-dioxo-9,10-dihydro-anthracen-2-yl-methyl)-malonic acid diethyl ester functionalities were synthesized from the corresponding phthalodinitrile 1 and divalent metal salts at 170 °C in fused state. Reaction of with manganese (2+) acetate in n-pentanol led to the manganese (3+) phthalocyanine 4. Furthermore, the unsymmetrical copper phthalocyanine 5 containing one 2-(9,10-dioxo-9,10-dihydro-anthracen-2-yl-methyl)-malonic acid diethyl ester moiety was synthesized using a statistical approach. The new compounds were characterized by elemental analysis together with FT-IR, ¹H-NMR, ¹³C-NMR, and UV–vis spectroscopy and via mass spectrometric analysis. The electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric measurements represent that while MPcs give common ring-based and/or metal-based electron transfer processes, these processes were considerably affected with the redox processes of the AQ units attached to the phthalocyanine ring. At the same time attachments of the AQ units to the phthalocyanine rings improve the reversibility of the AQ units due to the electron donor–acceptor interaction between the AQ units and phthalocyanine ring. The AQ units also alter the color states of the phthalocyanines.     

Isophorone-based analogues with A-π-D-π-A structure for red organic light emitting devices

New electroluminescent materials, two DCM analogues 1,4-Bis[2-[3-(1,1-dicyan ovinyl)-5,5-dimethyl-cyclohexeneyl]vinyl]benzene (1) and 1,4-Bis{2-[3-(1,1-dicya novinyl)-5,5-dimethyl-cyclohexeneyl]vinyl}-2,5-di-(n-butoxy)benzene (2) with A-π-D-π-A structure were synthesized and characterized. Optical properties (UV–vis and fluorescence) were studied for both compounds according to the spectra analysis. Theoretical calculation and cyclic voltammetry were used to analyzed the frontier molecular orbital of the two compounds. The result suggest that compound 2 can used not only as dopants but also as host emission and electron injection materials. Two kinds of red OLEDs were fabricated using 2 and all the devices achieved good CIE coordinates.     

Semiconducting polymers based on electron-donating bithiophene and electron-accepting 5,5′-bithiazole units for organic thin-film transistors

New type of π-conjugated polymers composed of electron-donating bithiophene and electron-accepting 5,5′-bithiazole were prepared by organometallic polycondensation using a zerovalent nickel complex, which have charge-transfer (CT) structures in the polymer backbone. The number average molecular weights (M_n) of the obtained polymers, PT2Z2-C8 and PT2Z2-H, were 45000 and 20000, respectively, estimated from GPC measurements. Head-to-head (HH) arrangements of 5,5′-bithiazole units leads to good solubility of the polymers in common organic solvents. Ionization potentials (IPs) of PT2Z2-C8 and PT2Z2-H were measured to be 5.15 and 5.20 eV, respectively. UV–vis peaks of the polymer films corresponding to the π–π* transition were shifted to longer wavelengths over 70 nm relative to those obtained for the corresponding chloroform solutions. PT2Z2-C8 is considered to have a coplanar π-conjugated backbone conformation, as judged from UV–vis data and XRD data. OTFTs fabricated using the polymer PT2Z2-C8 as a channel material show a typical p-type behavior and provide a mobility of 0.001 cm²/Vs with a low off-state current (of about 1 pA).     

Synthesis and spectroscopic properties of a series of octacationic water-soluble phthalocyanines

The synthesis, characterization of newly synthesized metal-free 2 and metallophthalocyanine complexes 3–5 (MPcs, M = Ni, Co, Cu) and quaternized metallophthalocyanine derivatives 3a, 5a (MPcs, M = Ni, Cu) containing 4,5-bis(quinolin-6-yloxy) substituents have been presented in this work. The new compounds have been characterized by using elemental analysis, UV–vis, IR, ¹H NMR, ¹³C NMR and MS spectroscopic data. Also, aggregation properties of Pcs were investigated at different concentrations in chloroform, dimethylformamide and water. The effect of the concentration on the aggregation properties of complexes 2–5 was studied in chloroform. No aggregation was demonstrated in chloroform from concentration between 1 × 10^?5 and 0.4 × 10^?5 M.     

Preparation,electrochemistry and optical properties of unsymmetrical phthalocyanines bearing morpholine and tert-butylphenoxy substituents

The synthesis of novel, unsymmetrical, octasubstituted metal-free and metallophthalocyanines (zinc, cobalt) bearing one chlorine, one morpholine moieties and six 4-tert-butylphenoxy substituents was achieved by a statistical condensation reaction of two corresponding phthalonitriles. The new compounds have been characterized by using elemental analyses, UV–vis, IR, ¹H NMR and mass spectroscopic data. Voltammetric and spectroelectrochemical studies are in harmony with the reported metallophthalocyanine complexes, which support the proposed structure of the complexes.     

Synthesis,characterization, and electrical,electrochemical and gas sensing properties of a novel cyclic borazine derivative containing three phthalocyaninato zinc(II) macrocycles

A novel borazine derivative of trinuclear phthalocyanine has been prepared by following the multistep reactions of unsymmetrically substituted phthalocyanines. 4-(4-Amino-3-nitrophenoxy)phthalonitrile (3) which is one of the precursor molecules of the phthalocyanine was obtained from 4-nitrophthalonitrile (1) and 4-amino-3-nitrophenol (2) with K₂CO₃ in DMF at 50 °C. The zinc(II) phthalocyanine (5) containing an unsymmetrical substituted 4-amino-3-nitrophenoxy group was synthesized by statistical condensation of two different phthalonitriles. 4-(4-Amino-3-nitrophenoxy)phthalonitrile (3) and 4,5-bis(hexylthio)phthalonitrile (4) were cyclotetramerized with zinc acetate in DMF at 170–180 °C to yield 2-(4-amino-3-nitrophenoxy)-9,10,16,17,23,24-hexa(hexylthio)phthalocyanine zinc(II) complex (5), which was then separated by column chromatography on silica gel. The unsymmetrically substituted compound was reduced to the diamine form (6) using hydrazine hydrate in the presence of Pd/C catalyst, and the product was purified with chromatographic separation. Compound 6 was then reacted with triisopropoxyborane in refluxing xylene to give 5H,12H,19H-tris[2-(3,4-diaminophenoxy)-9,10,16,17,23,24-hexa(hexylthio)phthalocyaninato zinc(II) diazaborolo] borazine (7). The resulting product was purified by column chromatography on silica gel. All the target unsymmetrical phthalocyanines and borazine derivative were characterized by elemental analysis, IR, UV–vis, and ¹H NMR. Boron and zinc(II) percents in 7 were quantified with ICP-MS. Impedance spectroscopy and dc measurements were performed on spin coated 5–7 films as a function of temperature (293–400 K). The dc results showed an activated conductivity dependence on temperature. The ac results gave a temperature dependent frequency exponent s. The results were compared with the prediction of the Quantum Mechanical Tunelling and Correlated Barrier Hopping models. The ac conductivity of the films was well represented by the form Aω^s. Gas sensing properties of the films for the volatile organic compounds (VOCs) (chloroform, acetone, carbontetrachloride and ammonia) were also investigated in the temperature range from 293 to 400 K. The operating temperature had a considerable effect on sensing characteristics. Maximum sensitivity to VOCs were observed at room temperature for all films. Cyclic voltammetry of compounds 6 and 7 in solution indicated that these compounds have similar voltammetric behaviour.     

Synthesis and third-order nonlinear optical studies of a novel four-coordinated organoboron derivative and a bidentate ligand: The effect of the N → B coordinative bond

The third-order nonlinear optical characterization of a new boronate (2) derived from 4-dimethylaminocinnamaldehyde was performed by third-harmonic generation (THG) at the infrared wavelength of 1550 nm. Compound 2 was prepared from the reaction of diphenylboronic acid and the bidentate ligand (1) and characterization was made through UV, IR, ¹H, ¹¹B, and ¹³C NMR and X-ray diffraction. The THG experiments showed that the N → B coordinative bond in 2 enhanced the second molecular hyperpolarizability of the type γ⁽³⁾(−3ω, ω, ω, ω) by a factor of three with respect to the value exhibited by the ligand 1. On the other hand, Z-scan studies at 800 nm (femtosecond (fs) pulses) also showed that such coordinative bond increased the nonlinear absorption (two-photon absorption (TPA)) in 2 with respect to 1. These studies demonstrate that the N → B coordinative bond facilitates the polarization of the electronic π-system, a situation that optimizes the third-order NLO response. Results on the excited state absorptions in these compounds are also presented.