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Three (4,4′-((1E,1′E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivatives were synthesized via a condensation reaction with p-toluenesulfonic acid as a catalyst. The effects of the end groups and vinylene (–HC=CH–) moieties on the structural, thermal, optical, electrochemical and photovoltaic properties of imines were investigated to check the influence of TiO2 on the imine properties. The thermal behavior of imines and their complexes with TiO2 was widely investigated using FT-IR, XRD, DSC and POM methods in order to determine the order type in the imine structure. All imines present the highest occupied molecular orbital (HOMO) levels of about −5.39 eV (SAI1 and SAI2) and −5.27 eV (SAI3) and the lowest unoccupied molecular orbital (LUMO) levels at about −3.17 eV. The difference of the end groups in the imines in each case did not affect redox properties. Generally, both oxidation and reduction are easier after TiO2 addition and it also changes the HOMO–LUMO levels of imines. Moreover, changes in the characteristic bands for imines in the region 1500–1700 cm−1 observed as a drastic decrease of intensity or even disappearance of bands in the imine : TiO2 mixture suggest the formation of a complex (C=N)–TiO2. Organic devices with the configuration of ITO/TiO2/SAIx (or SAIx : TiO2)/Au were fabricated and investigated in the presence and absence of visible light irradiation with an intensity of 93 mW cm−2. In all imines and complexes with TiO2, the generation of the photocurrent indicates their use as photodiodes and the best result was observed for SAI3 : TiO2 complexes. [ABSTRACT FROM AUTHOR]

Two bent-shaped imines (9E)-N-(3-((E)-(4-hexadecylphenylimino)methyl)benzylidene)-4-hexadecylbenzenamine (SL1) and (10E)-N-(3-((E)-(4-(perfluorooctyl)phenylimino)methyl)benzylidene)-4-(perfluorooctyl)benzenamine (SL2) were prepared by condensation reaction in N,N-dimethylacetamide to study their thermal, structural and electrochemical properties, as well as their mixtures with titanium dioxide. Chemical structure, temperature and TiO2 influences on the phase transition temperatures, enthalpy, texture and molecular dynamics of both imines were investigated by differential scanning calorimetry, polarising optical microscopy and Fourier transform middle-infrared absorption spectroscopy during heating and cooling. Changes in the surface morphology of the imines and their mixtures with TiO2 were registered by atomic force microscopy. X-ray study showed the tendency to form lamellas in the case of SL2 as an effect of the presence of two terminal perfluorinated alkyl chains connected to a polar mobile aromatic core, which resulted in microsegregation. Additionally, TiO2 influences the energy gap and HOMO-LUMO levels of imines as was detected by cyclic voltammetry. Finally, devices with two types of architectures, such as ITO/TiO2/SL1(or P3HT)/Au and ITO/TiO2/SL1:P3HT/Au were constructed and investigated under irradiation intensity of 97.7 mW/cm2. [ABSTRACT FROM AUTHOR]

A new piperazine imine, (7E)-N-((4-((E)-(4-hexadecylphenylimino)methyl) piperazin-1-yl)methylene)-4-dodecylbenzenamine, has been synthesized by the condensation of 1,4-piperazinedicarboxaldehyde with 4- hexadecylaniline. The imine was characterized by cyclic voltammetry, Fourier transform middle-infrared absorption spectroscopy and X-ray diffraction. Thermal properties of imine was analyzed by differential scanning calorimetry method during first and second heating scan at 10 and 20 °C/min. Texture of imine was investigated by polarized optical microscopy and atomic force microscopy. Furthermore, imine was blended with titanium dioxide in anatase form and fully characterized by the same methods. Piperazine imine and its mixture with titanium dioxide exhibited only a transition from crystal to isotropic state. Imine exhibits two-step reduction wave attributed to one-electron transfer in each step as was found by cyclic voltammetry. Both titanium dioxide and poly(3-hexylthiophene) change the electrochemical properties of piperazine imine, however, in different ways. Studied imine blended with titanium dioxide exhibited higher value of energy band gap than pure piperazine imine and lower Eg than pure poly(3-hexylthiophene). [ABSTRACT FROM AUTHOR]

Three (4,4'-((1E,1'E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivatives were synthesized via a condensation reaction with p-toluenesulfonic acid as a catalyst. The effects of the end groups and vinylene (-HC[double bond, length as m-dash]CH-) moieties on the structural, thermal, optical, electrochemical and photovoltaic properties of imines were investigated to check the influence of TiO2 on the imine properties. The thermal behavior of imines and their complexes with TiO2 was widely investigated using FT-IR, XRD, DSC and POM methods in order to determine the order type in the imine structure. All imines present the highest occupied molecular orbital (HOMO) levels of about -5.39 eV (SAI1 and SAI2) and -5.27 eV (SAI3) and the lowest unoccupied molecular orbital (LUMO) levels at about -3.17 eV. The difference of the end groups in the imines in each case did not affect redox properties. Generally, both oxidation and reduction are easier after TiO2 addition and it also changes the HOMO-LUMO levels of imines. Moreover, changes in the characteristic bands for imines in the region 1500-1700 cm-1 observed as a drastic decrease of intensity or even disappearance of bands in the imine : TiO2 mixture suggest the formation of a complex (C[double bond, length as m-dash]N)-TiO2. Organic devices with the configuration of ITO/TiO2/SAIx (or SAIx : TiO2)/Au were fabricated and investigated in the presence and absence of visible light irradiation with an intensity of 93 mW cm-2. In all imines and complexes with TiO2, the generation of the photocurrent indicates their use as photodiodes and the best result was observed for SAI3 : TiO2 complexes.

The effect of the presence of titanium dioxide in two new imines, ( E , E )-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4-{[(benzo[ d ][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and ( E )- N -[(benzo[ d ][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO 2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol-gel method) exhibited a surface area of 59.5 m 2 /g according to Brunauer-Emmett-Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett-Joyner-Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m 3 /g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Col hk ). The imine:TiO 2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO-LUMO energy levels compared to pure TiO 2 . This implies that TiO 2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO 2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO 2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO 2 surface with SP1 and SP2 were observed. The imine:TiO 2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications.