Metallopolymers based on a polyazomethine ligand containing rigid oxadiazole and flexible tetramethyldisiloxane units

Abstract

Soluble, easily processable polymer-metal complexes with improved optical and dielectric properties for optoelectronic functional materials were obtained. For this, a new polyazomethine (PAZ2) was prepared by the reaction of a siloxane dialdehyde and bis(formyl-p-phenoxymethyl) tetramethyldisiloxane with 2,5-bis(p-aminophenyl)-1,3,4-oxadiazole, and it was used as a ligand for Cu(II), Co(II), and Zn(II) ions on the basis of the presence of the electron-donor nitrogen atoms from the azomethine group and oxadiazole ring. The structure of the PAZ2 was determined by spectral [Fourier transform infrared (FTIR) and 1 H-NMR spectroscopy] techniques. The metal complexation was proven by FTIR spectroscopy, and the silicon-to-metal ratios in the complexes were established by energy-dispersive X-ray fluorescence. The new materials were characterized by gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. The optical properties of PAZ2 and the derived metal complexes were studied by ultraviolet-visible and fluorescence spectroscopies. PAZ2 shows fluorescence emission, and it was significantly enhanced by metal complexation. The emission was enhanced by protonation; this behavior is useful, especially for sensors. The electrical properties were investigated by dielectric spectroscopy at various frequencies and temperatures, and this emphasized the existence of dipolar relaxations.

Silylated oligomeric poly(ether-azomethine)s from monomers containing biphenyl moieties: synthesis and characterization

“…In general, the silicon atom is part of a siloxane moiety, which implies a Si-O bond. [20][21][22][23][24][25] In 2014, Zaltariov et al 26 reported a PAM with a central silicon atom bonded to four carbon atoms complexed with different metal ions. However, they used a methylene unit instead of an aromatic moiety bonded to a silicon atom which, along with other structural features, rendered the polymer too exible; thus, the T g measured for the polymer was 48 C. For a material to be used for charge transport in a PHOLED device, its T g value must be over 100 C to avoid deterioration of its mechanical properties under high temperature conditions.…”

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

“…Siloxane moieties (short segments, long chains, cycles) are often used in LCs as flexible spacers or as the main backbone, in combination with unnumbered mesogenic groups. The main reasons for using siloxanes instead of purely [54,[114][115][116] and illustration through 2D and 3D AFM (a,b) and TEM (c) images of their self-assembly that changes depending on the polarity of the environment.…”

Neural network modeling of the preparation process of a siloxane‐organic polyazomethine

“…Several alternative synthetic strategies such as creation of the molecular asymmetry by incorporating of noncoplanar groups in the main chain, attaching the bulky pendant groups, for instance, the introduction of substituents (alkyl or alkoxy groups) in the ortho-position of the aromatic ring or insertion of aliphatic flexible spacers between aromatic rings within the main chain are approached. 18 Siloxane moiety had also inserted as a flexible spacer, either in the amine or carbonyl component, resulting in polyazomethines with improved solubility [19][20][21][22][23][24][25] because of high flexibility of the siloxane bond and weak intermolecular interactions between dimethylsiloxane units. 4,17 The inclusion of polyazomethines in rotaxane architecture is another strategy approached to improve their processability.…”

“…4,17 The inclusion of polyazomethines in rotaxane architecture is another strategy approached to improve their processability. 18 Siloxane moiety had also inserted as a flexible spacer, either in the amine or carbonyl component, resulting in polyazomethines with improved solubility [19][20][21][22][23][24][25] because of high flexibility of the siloxane bond and weak intermolecular interactions between dimethylsiloxane units.…”