Synthesis of polyarylenephthalides prospective as smart polymers

The data on the synthesis of polyarylenephthalides, their analogs, and derivatives are surveyed. The main attention is given to the synthesis of polyarylenes through the polycondensation of pseudoacid chlorides according to several variants, predominantly via the self-condensation of pseudoacid chlorides, which may be depicted by the general scheme

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(?RH is the radical of aromatic or heterocyclic polynuclear hydrocarbon.). The reaction affords polyarylenephthalides (I) (X = CO, Y = O), polyarylenephthalimidines (II) (X = CO, Y = NR₁, where R₁ is an aromatic hydrocarbon), and polyarylenesulfophthalides (III) (X = SO₂, Y = O). Polymers I and II hold promise for designing thermostable, heat-(T _g ≥ 420–470°C) and chemoresistant, and functional materials. One should distinguish the valuable functional properties of polymers I and III that make them prospective as smart polymers, namely, the switching effect induced by temperature, pressure, and electric and magnetic fields along with changes in color, electro-and photoluminescence. Owing to the presence of sulfophthalide groups, polymers III are candidates for use as latent polyelectrolytes. With consideration for the foregoing reasoning, phthalide-containing polyarylenes of several other classes, namely, polyaryleneketones, poly(arylene ether ketones), polyarylates, oligomer resols, and crosslinked systems on their basis, which are prospective as smart polymers, have been synthesized.

     

Formation of color centers and paramagnetic species upon reduction of poly(diphenylene phthalide) with metallic lithium in DMF

Reduction of poly(diphenylene phthalide) (PDP) with metallic lithium in DMF at room temperature was studied by electronic and ESR spectroscopies. The main feature of the process is the presence of a long induction period (about 50 to 80 min) which is probably caused by the formation of small lithium particles and by adsorption of the polymer on the metal. At least four types of nonparamagnetic color centers characterized by overlapping absorption bands at 570, 660, 750, and 810 nm were detected in the reduced solution. The amounts of all types of the color centers in the solution show a complex dynamic behavior. Reduction of the polymer in the bulk of the solution is due to lithium colloid particles which give rise to a narrow asymmetric ESR singlet (g = 2.0023, ΔH = 0.03 mT, A/B ≈ 1.1–1.8) and absorb light in the region λ ～300–400 nm. Paramagnetic species with quartet ESR signal with a splitting of 0.1 mT and g = 2.0045 observed in the solutions being reduced at a polymer concentration of 0.2 mol L^?1 were attributed to radical anions of terminal anthraquinone groups (TAGs). The electron affinities of some molecules simulating the phthalide-containing unit of the polymer backbone, TAG, and a defect anthrone group were calculated in the B3LYP/6-311+G(d,p) approximation. For diphenylphthalide, the vertical electron affinity EA_vert = 0.21 eV, the adiabatic electron affinity EA_ad = 0.66 eV, the effective electron affinity EA_eff (with allowance for cleavage of C-O bond in the phthalide ring) = 1.23 eV. For anthrone group, one has EA_ad ～1.2 eV and for anthraquinone group, EA_ad ～2 eV. The electron affinities of the model compounds were also calculated with inclusion of the energy of solvation in two solvents (DMF and DMSO) and the energy of polarization in the PDP film. The electronic spectra of some compounds chosen as models for the expected products of reduction (anions and dianions) of the main phthalide-containing fragments in the polymer, TAGs, and defect anthrone groups were also calculated by the TD DFT B3LYP/6-311G(d,p) method. The presence of three types of chemical electron traps and the possibility of manifestation of strong absorption bands of these anions and dianions in the spectral region 500–900 nm precludes unambiguous selection and assignment of complex experimental electronic spectra observed in the course of PDP reduction. The possible role of TAGs in the electronic and photophysical processes in PDP is discussed.     

Comparison of Extractive Capacities of Systems Based on Sulfonol,Sodium Dodecyl Sulfate,or Alkyl Benzene Sulfonic Acid

Russian Journal of Applied Chemistry - Effect of organic complexing reagents: diantipyrylmethane, diantipyrylbutane, diantipyrilheptane, 1,10-phenanthroline, and 1,2,3-benzotriazole, on the phase...     

Formation of mono-, bi-, and polyradicals upon reduction of poly(arylenesulfophthalides) by metallic lithium

The reduction of poly(biphenylenesulfophthalide) (1), poly(fluorenylenesulfophthalide) (2), and poly(terphenylenesulfophthalide) (3) by metallic lithium in DMSO was studied using UV-visible and ESR spectroscopies. The reduction of compounds 1 and 2 affords blue diamagnetic color centers with absorption bands at 568 and 350 nm (shoulder) for 1 and at 576 and 360 nm (shoulder) for 2. The color centers were attributed to quinoid structures of the Chichibabin"s hydrocarbon type, being biradicals in the ground singlet state. The spectra of compounds 1 and 2 also exhibit weak absorption bands at 420 nm, which are assigned to monoradicals of the triarylmethyl type. The reduction of compound 3, for which the formation of quinoid structures is energetically unfavorable, leads to polyradicals of the triarylmethyl type with a high content (100%) of unpaired electrons in the main polymer chain. These radicals are characterized by absorption bands at 430 nm (allowed transition) and 638 nm (forbidden transition). The paramagnetic centers in all polymers under study give singlet lines with g = 2.0028 and H 10 Oe in the ESR spectra. The color centers and radicals of the triarylmethyl type observed for the poly(arylenesulfophthalides) under study are assumed to be formed upon the dissociative electron transfer from lithium to the sulfophthalide cycles of the polymeric molecules. The PM3 calculations show a high electron affinity of the sulfophthalide cycle and a higher propensity of the fluorenyl bridge to form quinoid structures than that of the biphenyl bridge.     

Control over the Composition and Microstructure of Copoly(Arylene Phthalides)

The possibility of controlling the composition, microstructure, and molecular weight of copoly(arylene phthalides) was examined.     

Reduction of the radioactivity in sodium iodide (NaI) powder by recrystallization method

The COSINE experiment is searching for dark matter using ultra-low background NaI scintillating crystals. In order to reduce the internal contamination of the initial NaI powder to grow NaI crystals, NaI powder samples with different purities were purified by fractional recrystallization using de-ionized water. The concentrations of the main radioactive elements, K, Pb, Th, and U, which are major backgrounds for the dark matter search, were reduced to the level required for the experiment. Further, the concentrations of other impurities, e.g., Ba, Ca, Cr, and Fe, were also reduced, which is important to realize good quality NaI crystals.     

Voltamperometry of Aromatic Nitro Compounds Using a Multisensor System of Electrodes Modified with Poly(Arylene Phthalide Ketones)

Electrodes modified with poly(arylene phthalide ketones) were developed for the voltammetric determination of isomers of aromatic nitro compounds. A polynomial algorithm for processing analytical signals from a sensor array was tested in the analysis of ternary mixtures. It is shown that the sensor array offers promise for analyzing multicomponent mixtures in the case when analytical signals overlap.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 576–581.Original Russian Text Copyright © 2005 by Sidel’nikov, Maistrenko, Kudasheva, Kuz’mina, Sapel’nikova, Gileva.Presented at the VI All-Russia Conference (with international participation) on Electrochemical Methods of Analysis (EMA-2004, Ufa, May 23–27, 2004).     

NMR study of dyadic and triadic splitting in copoly(arylene)phthalides based on diphenyl oxide and diphenyl sulfide

All ¹³C NMR signals of the poly(arylene) polymers, O‐1 , S‐7 , OS‐4 , OOS‐3 , OOOS‐2 , SSO‐5 , and SSSO‐6 (where O is a diphenyleneoxiphthalide unit and S is a diphenylenethiophthalide unit) in dyads and triads were assigned unequivocally with two‐dimensional NMR techniques (ge‐2D [¹H–¹H] COSY, ge‐2D [¹H–¹³C] HSQC, and ge‐2D [¹H–¹³C] HMBC), and for each atom, the increments of the shifts are determined. For structurally similar carbon atoms of the phthalide cycle and heteroaromatic fragments of the skeletal chain, additive signal splitting schemes in phthalide centered dyads and in diphenylene oxide and in diphenylene sulfide centered triads are considered, based on taking into account the contributions to their shielding of adjacent and distant substituents. It was shown that the nature of the splitting of the signals of each of the 20 carbon atoms in 3,3‐bisphenylphthalide fragments is determined by the type of carbon atom (tertiary or quaternary, even or odd), the type of heteroatoms in adjacent heteroaromatic fragments, their distance from the identified carbon nucleus, and their polyad symmetry. The results obtained in this article will greatly facilitate our further studies and, in particular, will allow us to study the microstructure of statistical copolymers based on the asymmetric OS monomer at the dyad and triad levels.