Synthesis and characterization of wholly aromatic poly(azomethine)s containing donor–acceptor triphenylamine moieties

Photocatalytic degradation of organic pollutants through conjugated poly(azomethine) networks based on terthiophene-naphthalimide assemblies

A conjugated poly(azomethine) network based on ambipolar terthiophene–naphthalimide assemblies has been synthesized and its electrochemical and UV-vis absorption properties have been investigated. The network has been found to be a promising candidate for the photocatalytic degradation of organic pollutants in aqueous media.

A conjugated two-dimensional poly(azomethine) network based on ambipolar terthiophene–naphthalimide assemblies has been synthesized and its electrochemical and UV-vis absorption properties have been investigated.

New Triphenylamine-Based Oligomeric Schiff Bases Containing Tetraphenylsilane Moieties in the Backbone

Three new triphenylamine-based oligomeric Schiff bases (polySB1, polySB2 and polySB3) containing tetraphenylsilane core (TPS-core) in the main chain were obtained from TPS-core-based diamines and bis(4-formylphenyl)phenylamine by a high-temperature polycondensation reaction. These new oligomers were structurally characterized by FT-IR, NMR and elemental analysis. All polySBs were highly soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene. Samples showed moderate molecular average molecular weight (Mw) and a high thermal stability above 410 °C. Likewise, polySBs showed absorption near 400 nm in the UV-vis range and photoluminescence. The HOMO levels and band-gap values were found in the ranges of -6.06 to -6.18 eV and 2.65⁻2.72 eV, respectively. The lowest band-gap value was observed for polySB2, which could be attributed to a more effective π-conjugation across the main chain. The results suggest that silicon-containing polySBs are promising wide-band-gap semiconductors materials for optoelectronic applications.

Synthesis and Photophysical Study of New Green Fluorescent TPA Based Poly(azomethine)s

A series of poly(azomethine)s (PAMs) were synthesized from N¹-(4-aminophenyl)-N¹-(4-phenoxyphenyl)benzene-1,4-diamine (DA) and various dialdehydes to investigate the influence of structure of polymer chain and triphenylamine-based phenoxy pendant group on the optoelectronic properties. The structural characterization of the resulting poly(azomethine)s was carried out by solubility test, gel permeation chromatography, viscosity measurement, fourier transform infrared (FTIR) spectral and CHN elemental analysis. The photophysical and electrochemical properties of the materials were scrutinized by UV-vis, photoluminescence, time correlation photon counting spectral analysis (TCSP) and cyclic voltammetry. The thermal stability of the poly(azomethine)s was assessed by differential scanning calorimetry and thermogravimetric analysis found to be stable upto 300 °C. These polymers exhibit moderate inherent viscosity range from 0.99 to 1.15 g dL^- 1 and appreciable organosolubility. The presence of triphenylamine and azomethine (CH = N) linkage in our synthesized materials rendered them fluorescent, emitting green light upon excitation at 375 nm with quantum efficiencies of 3.9-8.5%. The pendant phenoxy group at para-position in new poly(azomethine)s has also lowered the onset oxidation potentials and elevated the HOMO levels. Additionally, the presence of conjugation increases the fluorescence time of the excited state in conjugated polymers which was found in the range 9.22-11.17 ns, sufficient to be use in future optoelectronic applications.

Polyazomethine with vinylene and phenantridine moieties in the main chain: Synthesis, characterization, opto(electrical) properties and theoretical calculations

The opto(electrical) properties and theoretical calculations of polyazomethine with vinylene and phenantridine moieties in the main chain were investigated in the present study. 2,5-Bis(hexyloxy)-1,4-bis[(2,5-bis(hexyloxy)-4-formyl-phenylenevinylene]benzene was polymerized in solution with 3,8-diamino-6-phenylphenanthridine (PAZ-PV-Ph). The temperatures of 5% weight loss ( T5%) of the polyazomethine was observed at 356 °C in nitrogen. Electrochemical properties of thin film of the polymer were studied by differential pulse voltammetry. The HOMO level of the PAZ-PV-Ph was at −4.97 eV. The energy band gap ( Eg) was detected of approximately ∼1.9 eV. Energy band gap ( Egopt) was additionally calculated from absorption spectrum and absorption coefficient α. The absorption UV-vis spectra of polyazomethine recorded in solution showed a blue shift in comparison with the solid state. HOMO-LUMO levels and Eg were additionally calculated theoretically by density functional theory and molecular simulations of PAZ-PV-Ph are presented. Current density–voltage ( J– U) measurements were performed on ITO/PAZ-PV-Ph/Al, ITO/TiO2/PAZ-PV-Ph/Al and ITO/PEDOT/PAZ-PV-Ph:TiO2/Al devices in the dark and during irradiation with light (under illumination of 1000 W m−2). The polymer was tested using AFM technique and roughness ( Ra, Rms) along with skew and kurtosis are presented.

Synthesis and electrochemical characterization of new linear conjugated arylamine copolymers

New conjugated copolymers having linear structures were synthesized by palladium catalyzed cross-coupling reactions of bis(4-bromophenyl)phenylamine or 4-hydroxymethyl-N,N’-bis(4-bromophenyl)aniline and two bisboronic acids of fluorene or thiophene. The copolymers were obtained as fully or partially soluble materials, in chlorinated and aprotic polar solvents. Having a hydroxymethyl group attached to the para position of the triphenylamine units, the synthesized copolymers can be viewed as functional polymers which were transformed into new ones by employing suitable chemical reactions. A new copolymer was obtained by coupling the hydroxymethyl group of triphenylamine of P35 copolymer, with phenyl isocyanate. The chemical structures and the properties of copolymers were investigated by spectroscopic methods such as 1H nuclear magnetic resonance, Fourier transform infrared, ultraviolet-Vis and photoluminescence spectroscopy. Cyclic voltammetry was performed in order to obtain information about the electrochemical stability and reversibility of the redox processes of copolymers. Electrochemical studies were carried out on films cast on glassy carbon electrode (GCE) or In-Tin oxide (ITO) glass-coated electrode.