Synthesis and fluorescent properties of model compounds for conjugated polymer containing maleimide units at the main chain

2,3‐Diaryl substituted maleimides as model compounds of conjugated maleimide polymers [poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar)] were synthesized from 2,3‐dibromo‐N‐substituted maleimide (DBrRMI) [R= cyclohexyl (DBrCHMI) and n‐hexyl (DBrHMI)] and aryl boronic acid using palladium catalysts. To clarify structures of conjugated polymer containing maleimide units at the main chain, ¹³C NMR spectra of 2‐aryl or 2,3‐diaryl substituted maleimides were compared with those of N‐substituted maleimide polymers. Copolymers obtained with DBrRMI via Suzuki‐Miyaura cross‐coupling polymerizations or Yamamoto coupling polymerizations were dehalogenated structures at the terminal end. This dehalogenation may contribute to the low polymerizability of DBrRMIs. On the other hand, the π‐conjugated compounds showed high solubility in common organic solvents. The N‐substituents of maleimide cannot significantly affect the photoluminescence spectra of 2,3‐diaryl substituted maleimides derivatives. The fluorescence spectra of poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar) varied with N‐substituents of the maleimide ring. When exposed to ultraviolet light of wavelength 352 nm, a series of 1,4‐phenylene‐ and/or 2,5‐thienylene‐based copolymers containing N‐substituted maleimide derivatives fluoresced in a yellow to blue color. It was found that photoluminescence emissions and electronic state of π‐conjugated maleimide derivatives were controlled by aryl‐ and N‐substituents, and maleimide sequences of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Preparation of Metallaiminophosphoranes and Their Reactivity

Treatment of [Cp*(CO) 2 M{P(NHPh)(OMe) 2 }]PF 6 (M = Fe and Ru) with NaNH 2 gives metallaiminophosphoranes, Cp*(CO) 2 M{P(NPh)(OMe) 2 }. The x-ray structures and reactivity of the complexes are reported.     

Synthetic Utilization of α-Phosphonovinyl Anions

The α-phosphonovinyl anions, generated in situ from treatment of β-hetero-substituted vinyl-phosphonates 1a-c with LDA (or LTMP), were trapped with various electrophiles such as chlorotriorganosilanes, chlorotrimethylgermane, chlorotriorganotins, dimethyl disulfide, and halogen to afford the corresponding β-hetero-substituted α-functionalized vinylphosphonates 2–14 in good to excellent yields. The Friedel-Crafts reaction of α-(silyl) or α-(germyl)phosphonoketene dithioacetals 2, 9 or 4 with acid chlorides gave α-acylated phosphonoketene dithioacetals 15–19 in 53–91 % yields. The palladium-catalyzed cross-coupling reaction of β-ethoxy-α-(tributylstannyl)vinylphosphonate 13 with a variety of organic halides (R = acyl, allyl, aryl etc.) provided β-ethoxy-α-substituted vinylphosphonates 20–25 in good to moderate yields. The palladium-mediated cross-coupling reaction of α-(iodo)-vinyl-phosphonates 7, 14 with terminal acetylenes afforded α-alkynylated vinylphosphonates 26–29 in 69–83 % yields.     

Preparation and characterization of conducting polyaniline layered magnetic nano composite polymer particles

Considering the application potentials of organic materials possessing both conducting and ferromagnetic functions in various electronic devices, an attempt was made to prepare conducting polyaniline (PANI) layered magnetic nano composite polymer particles. Two routes were used to modify magnetic Fe₃O₄ core particles. In one route, seeded emulsion polymerization of methyl methacrylate (MMA) was carried out in presence of nano‐sized Fe₃O₄ core particles. In another route, cross‐linker ethyleneglycol dimethacrylate (EGDM) was used in addition to MMA. The modified composite particles were named as Fe₃O₄/PMMA and Fe₃O₄/P(MMA‐EGDM), respectively. Finally, seeded chemical oxidative polymerization of aniline was carried out in the presence of Fe₃O₄/PMMA and Fe₃O₄/P(MMA‐EGDM) composite seed particles to obtain Fe₃O₄/PMMA/PANI and Fe₃O₄/P(MMA‐EGDM)/PANI composite polymer particles. The modification of Fe₃O₄ core particles was confirmed by electron micrographs, FTIR, UV–visible spectra, X‐ray photoelectron spectra, X‐ray diffraction pattern and thermogravimetric analyses. A comparative study showed that crosslinking of intermediate shell improved the magnetic susceptibility and electrical conductivity of PANI layered magnetic nano composite particles. Copyright © 2013 John Wiley & Sons, Ltd.     

Vinyl Polymerization. 418. Polymerization of Vinyl Monomer Initiated by Betaine-Type Polymers in Aqueous Solution

Abstract

Three kinds of betaine-type polymers, which are macromolecular amphoteric electrolytes, were found to be able to polymerize vinyl monomers in aqueous solution through a radical mechanism without any further initiator. Betain-type polymers form hydrophobic areas (HA) in water. Vinyl polymerization commenced in the HA. The effect of the pH of the aqueous solution on polymerization was investigated.     

Vinyl Polymerization. 431. Vinyl Polymerizations Initiated by Block and Random Poly(Styrene-co-Sodium Methacrylate)

Abstract

The polymerization of some kinds of vinyl monomer was found to occur without an ordinary initiator in aqueous solutions of AB-type block or random copolymers of sodium methacrylate with styrene as a so-called “uncatalyzed polymerization.” Although the spin trapping technique showed that the initiation mechanism by the block copolymer was the same as that by the random copolymer, the initiating ability of the block copolymer was lower than that of the random copolymer. Such results are attributable to the difference in the incorporating ability of monomer into the micelles formed by the block copolymer and into the hydrophobic areas formed by the random copolymer.     

Asymmetric Induction Copolymerization of Optically Active N-(1-Menthyl Carboxylatomethyl) Citraconimide with Methyl Methacrylate

Copolymerization of an optically active N-(1-menthyl carboxylatomethyl)citraconimide (MCMCI) was carried out with methyl methacrylate (MMA) with azobisisobutyronitrile as the initiator in benzene at 50°C. All the copolymers obtained were optically active. After the removal of the optically active menthyl group, the hydrolyzed poly(MCMCI-co-MMA)'s still showed optical activity. The asymmetric induction to the copolymer main chain and the mechanism are discussed based on the measurements of optical rotatory dispersion and circular dichroism of the original and hydrolyzed copolymers.     

Synthesis and Polymerization of N-(L-Menthylcarboxylatomethyl)maleimide

A new type of optically active N-(L-menthylcarboxylatomethyl)maleimide (MGMI) was synthesized from maleic anhydride, glycine, and L-menthol. Radical homopolymerization of MGMI was performed at 50°C for 24 h to give optically active polymer having [α]_D = -57°. Radical copolymerizations of MGMI (M ₁) were performed with styrene (ST, M ₂), methyl methacrylate (MMA, M ₂) in benzene at 50°C. From the results, the monomer reactivity ratios (r ₁, r ₂) and the Alfrey-Price Q, e values were determined as follows: r ₁ = 0.16, r ₂ = 0.006 for the MGMI-ST system; r ₁ = 0.15, r ₂ = 1.65 for the MGMI-MMA system, and Q ₁ = 0.72, e ₁ = 1.59 calculated from the MGMI-MMA system. Anionic homopolymerizations of MGMI were also carried out. Chiroptical properties of the polymers were investigated.