Runxiong Lin

Rational design of a fluorescent poly(N-aryleneindole ether sulfone) switch by cation–π interactions

Semirigid poly(N-aryleneindole ether sulfone) (PESIN) as a fluorescence emission on–off switch has been successfully achieved via the cation–π interactions. The adjustment of the protonation/deprotonation status of pyridine that regulates the formation of cation–π interactions is definitely the determinant.

Synthesis of indole-based functional polymers with well-defined structures via a catalyst-free C-N coupling reaction†

Poly(N-arylene diindolylmethane)s (PMDINs) with precise structures and high molecular weights (Mw up to 389 200) in high yields (up to 95%) were synthesized by the catalyst-free nucleophilic substitution polycondensation of 3,3′-diindolylmethane with different activated difluoro monomers via a C–N coupling reaction process. A model reaction was carried out to assist in determining the optimal reaction conditions for the polymerization and to elucidate the chemical structures of the polymers. The resulting polymers exhibited good thermal stability with high decomposition temperature (T5% ≥ 377 °C). Fluorescent spectral studies indicated that all these PMDINs had strong solid-state fluorescence. Especially, the polymer PMDIN-3 carrying sulfonyl units was a good blue-light emitter with high quantum yields (21.6%, determined against quinine sulfate). The results obtained by cyclic voltammetry suggested that PMDINs possessed good electroactivity. In addition, owing to the electrochemical activity of the indole rings at the 2-position, PMDIN-3 was readily cross-linked by electrochemical oxidation and the cross-linking film was characterized by scanning electron microscopy. High molecular weights and good comprehensive performance of the indole-based polymers suggested that the catalyst-free C–N coupling reaction of indole derivatives with difluoro monomers could be considered as an effective polymerization route for the synthesis of new functional polymers with well-defined structures.

SYNTHESIS AND PHOTOPHYSICAL PROPERTIES OF POLY(ARYL IMINO) CONTAINING ACRIDINE UNITS (PAIA)

1,4-Bis-(4-bromobenzoyl)benzene and proflavine, 3,6-diaminoacridine free base were synthesized first. Using 1,4-bis-(4-bromobenzoyl)benzene and proflavine, 3,6-diaminoacridine free base as the monomers, poly(aryl imino) containing acridine units (PAIA) was synthesized via palladium-catalyzed amination. The structure of PAIA was characterized by means of FTIR, 1H-NMR spectroscopy and elemental analysis, the results show an agreement with the proposed structure. The UV absorption and photoluminescence spectra were tested. The absorption spectrum of the PAIA was dependent on the acidity of the media. The emission and excitation spectra of the two different forms of PAIA were investigated by photoluminescence, the addition of the trifluoroacetic acid (TFA) to the solution of PAIA does not lead to a quenching effect in the photoluminescent spectra. Additionally, DSC and TG measurements show that PAIA possess high glass transition temperature (Tg > 230°C) and good thermal stability with high decomposition temperatures in nitrogen atmosphere (TD > 500°C).

SYNTHESIS AND PROPERTIES OF NOVEL POLY(IMINO KETONE)S AS HIGH-PERFORMANCE POLYMERS *

Di(4-bromophenyl)ketone and various aromatic diamines as the monomers, a series of novel poly(imino ketone)s (PIKs) have been synthesized via palladium-catalyzed aryl amination, which is Hartwig-Buchwald polycondensation reaction. The structures of PIKs are characterized by means of elemental analysis, FT-IR, 1H-NMR and UV-Vis spectroscopy. The results show a good agreement with the proposed structure. The general properties of PIKs are studied by DSC, TG and wide-angle X-ray diffraction, the solubility behavior is measured at polymer concentration 5 mg·mL-1. It is obvious that PIKs show high glass transition temperature (Tg > 220°C), good thermal stability with high decomposition temperatures (TD > 480°C) and excellent solubility.

Intermolecular hydrogen bonding of polyiminosulfone

Molecular dynamics calculations were made of the distance from the hydrogen atom of the imino group to the oxygen atom of the sulfone group of polyiminosulfone (PIS). The results showed that theoretically there was hydrogen bond formation between the imino group and the sulfone group of PIS. The existence of the hydrogen bonding between the polymer chains of PIS was confirmed by infrared spectrum analysis. Due to the existence of the hydrogen bonding, PIS showed strong molecular interaction with a large cohesive energy density (CED), and a high glass transition temperature (282°C).

Synthesis of poly (imino ketone)s by palladium catalysis C-N cross-coupling reaction

In this paper, taking Pd2(dba)3 as catalyst and 2,2′-bis-(diphenylphosphino)-1,1′-binaphtyl as ligand, six kinds of poly(imino ketone)s (PIKs) with different structures have been synthesized via palladium catalysis C-N cross-coupling reaction. The structures of polymers synthesized was characterized by means of FTIR and NMR spectroscopy, the results showed an agreement with the proposed structures. The influential disciplines of monomer concentration and catalysis system to PIKs molecular weight were discussed. Differential scanning calorimetry measurement showed that PIKs possessed high glass transition temperatures (Tg > 150°C).

Molecular Simulations of Physical and Chemical Properties of Poly(Imino Ketone)s

Six kinds of poly(imino ketone)s (PIKs) with different structures were designed, involving different ratios of carbonyl and imino groups, and the insertion of two types of bulky groups in the main chain. Under 3D periodic boundary conditions, simulations of physical and chemical properties for PIKs with six different structures on the molecular level, including fractional free volume (FFV) and melt density, solubility, and glass transition temperature, were carried out.

Synthesis and properties of poly(arylene imino) containing fluorenone group (PIKF)

Abstract A series of novel poly(arylene imino) containing fluorenone group (PIKF) have been synthesized via palladium-catalyzed polycondensation. The thermal properties of PIKF are detected by thermal behavior (TG) and differential scanning calorimetry (DSC). UV-vis absorption spectra, photoluminescence are investigated. PIKF exhibit good thermal stability and high Tgs(>200 °C ). The optical properties of PIKF show that PIKF are interesting materials for further investigations to be presented as possible candidates for use as an electron transport layer (n-type) in multilayer LEDs.

Poly(imino imino ether ether ketone ketone) as novel soluble heat-resistant polymer

In this paper, we introduce a novel high-performance polymer, poly(imino imino ether ether ketone ketone), which has been synthesized by the palladium-catalyzed C-N cross coupling reaction of 1,4-bis-(4-bromobenzoyl) benzene and 1,3-bis-(4-aminophenoxy) benzene. The structure of the polymer is characterized by means of 1H NMR spectroscopy and elemental analysis, and the results show a good agreement with the proposed structure. Compared with traditional poly(ether ether ketone)s, the solubility of the synthesized polymer in common organic solvents was higher; it also exhibited high glass transition temperature (T g = 176°C) and good thermal stability with high decomposition temperature (T 5 = 400°C).