Synthesis,electrochemistry, and electrochromic properties of branched thiophene polymers with different conjugation lengths

Here the authors designed and synthesized three branched thiophene polymers with different effective conjugation lengths of thiophene groups, pTPBT, pTPTT, and pTPQT, mainly based on bithiophene, trithiophene, and quadruple thiophene. The electrochemical curves and theoretical calculation results reflect that the oxidation potential of polymers decreased gradually as the conjugation lengths of thiophene groups increased, which is favorable for the appearance of electrochromism. Electrochromic properties demonstrate that pTBTT displays no electrochromism, pTPTT exhibits an unstable one, while pTPQT shows an obvious stable electrochromism between yellow‐orange and blue‐violet colors. These results indicate that thiophene polymers with effective electrochromism should be the smallest conjugation length of quadruple thiophene at least. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2340–2348     

Preparation of polymer electrolyte membranes based on poly(phenylene oxide) with different side chain lengths of phosphonic acid

A series of poly(phenylene oxide) (PPO) polymers bearing phosphonic acid groups on the methyl group and on the phenyl ring are synthesized as membrane materials for fuel cell applications. These phosphonic acid‐based PPO membranes exhibited high chemical resistance, dimensional stability, and good proton conductivity even under low humidity condition. Among the membranes, the one in which the phosphonic acid moiety is attached to the polymer main chain with ? CO(CH₂)₅? shows highest proton conductivity under overall conditions even though it has the lowest water uptake and IEC value. A well‐defined separation of the hydrophilic and hydrophobic phases suggests the phosphonic acid groups to form proton conduction channels via interchain hydrogen bonding. A high storage modulus of the membranes in various temperature ranges indicates that the membranes are suitable for use under a high temperature and low humidity conditions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019     

Synthesis of novel symmetrical, single-chain, diacetylene-modified bolaamphiphiles with different alkyl chain lengths

Abstract  

General syntheses of novel symmetrical, single-chain, diacetylene-modified bolaphospholipids have been carried out in five steps. For the ω-alkynols, which have an important role as key intermediates, three different synthetic approaches were comprehensively investigated. For the final synthesis it is suggested that (1) alkylation of lithium (trimethylsilyl)acetylide with tetrahydropyranyl-protected ω-bromoalcohols, followed by (2) cleavage of the trimethylsilyl moiety and the tetrahydropyranyl protecting group, and (3) copper(II)-catalyzed Eglinton coupling is the best strategy for obtaining diacetylene-modified alkane-1,ω-diols, because higher yields were obtained while avoiding the formation of by-products. Moreover, conversion of the diols into bipolar phospholipids was achieved by bis-phosphorylation with β-bromoethylphosphoric acid dichloride and subsequent quaternization with trimethylamine or dimethylamine. Finally, spectral data are presented for novel single-chain, diacetylene-modified bolaphospholipids with promising potential as starting molecules in the formation of polymerizable and, thus, thermostable nanofibers.     

Synthesis of soluble poly(para‐phenylene) with a long polymer chain: Characteristics of regioregular poly(1,4‐phenylene)

Soluble poly(para‐phenylene) having a long polymer chain (more than six repeat units) was synthesized with a tert‐butyl end‐group (t‐PPP) and was found to have improved solubility and excellent optical properties. Poly(1,3‐cyclohexadiene) (PCHD) consisting of only 1,4‐cyclohexadiene (1,4‐CHD) units was synthesized with a tert‐butyl end‐group (t‐PCHD), and completely dehydrogenated to obtain t‐PPP. This end‐group effectively prevented the crystallization of t‐PPP, and polymers containing up to 16 repeat units were soluble in tetrahydrofuran. Soluble t‐PPP obtained had an ability to form a tough thin film prepared by spin‐coating method. Optical analyses of t‐PPP provided strong evidence for a linear polymer chain structure. A block copolymer of t‐PPP and a soluble polyphenylene (PPH) was then synthesized, and the excellent optical properties were retained by this block copolymer along with its solubility. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5223–5231, 2008     

Gel Formation during the Gilch Synthesis of Poly(p‐phenylene vinylenes): Evidence of an Unexpected Explanation

Gelation of the reaction mixture and insolubility of the poly(p‐phenylene vinylenes) (PPVs) when isolated at this stage, but complete redissolution of the gel and excellent solubility of the resulting PPVs after further stirring for hours or days, is a phenomenon in Gilch polymerizations that has not been explained so far. It is verified that, in agreement with the literature, specific additives prevent gelation. However, it is also shown that chemical crosslinking is certainly not the reason for gel formation. Instead, it seems to be the consequence of a very high entanglement density in the pristine PPVs, which requires time for relaxation. The mentioned additives seem to support this dis‐entanglement process.

     

Dicarboxylic imide‐substituted poly(p‐phenylene vinylenes) with high electron affinity

Synthesis of n‐type organic semiconductors with high electron mobilities, good environmental stability, and good processability is an urgent task in current organic electronics. This is because most of π‐conjugated materials are p‐type and prefer to transport positive hole carriers. In this article, a series of new dicarboxylic imide‐substituted poly(p‐phenylene vinylenes) (DI‐PPVs) were first synthesized. They exhibited a high electron affinity of 3.60 eV and thus are able to transport electrons. The polymers showed tunable solubility in common organic solvents and high chemical and thermal stability. They remain rigidity of the PPV backbone, and strong interchain π‐stacking was observed in thin films by X‐ray diffraction measurement. All these suggested that these polymers could serve as good candidates as n‐type semiconductors in organic electronic devices such as n‐channel field‐effect transistors and all polymer‐based solar cells. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 186–194, 2010     

Electronic energy structure of MBiS2 (M = Li, Na, K) calculated with allowance for the difference between the M-S and Bi-S bond lengths

The modified augmented plane wave method (WIEN2k program) was used to study the electronic energy structure and calculate the SK-absorption spectra of LiBiS₂, NaBiS₂, and KBiS₂. The crystal structures of the compounds were modeled using symmetric structures, in which each sulfur atom was surrounded by three alkali metal atoms and three bismuth atoms in such a way that the alkali metal-sulfur and bismuth-sulfur bond length differed. This difference between bond lengths was calculated from the sum of the ionic radii of the components of compounds and by the geometry optimization of the crystal lattice. The two variants of calculation allowed us to check the applicability of Pauling’s idea about preservation of the bond lengths of elements in compounds for modeling the crystal structures of LiBiS₂, NaBiS₂, and KBiS₂. The SK absorption spectra and optically forbidden bands were calculated.     

邻-二(吡咯-2-甲酰胺基)亚苯的合成、晶体结构及阴离子识别

设计合成了邻-二(吡咯-2-甲酰胺基)亚苯.用X射线单晶衍射研究了该化合物的固态构象,发现其可以通过氢键与DMSO发生络合.¹HNMR研究发现该化合物即使在强极性的DMSO溶液中也可对F^-,Cl^-和H₂PO₄^-常见阴离子产生一定的识别,其中对F-的识别为最优.     

The Gilch Synthesis of Poly(p‐phenylene vinylenes): Mechanistic Knowledge in the Service of Advanced Materials

A consistent picture is presented of the mechanistic details and intermediates of the Gilch polymerization leading to poly(p‐phenylene vinylenes) (PPVs). In‐situ generated p‐quinodimethanes are shown to be the real monomers, and spontaneous formation of the initiating radicals is effected by dimerization of some of these monomers to dimer diradicals, the latter also being the reason why significant amounts of [2.2]paracyclophanes are formed as side‐products. Chain propagation predominantly proceeds by radical chain growth, occasionally interrupted by polyrecombination events between the growing α,ω‐macro‐diradicals. Based on this knowledge, oxygen is identified as a very efficient molar‐mass regulating agent, and the temporary gelation of the reaction mixtures is interpreted to be the consequence of a very high entanglement of the polymers immediately after their formation. Last but not least, it is rationalized why the usually considered constitutional defects in Gilch PPVs might not be the only and most relevant ones with respect to the efficiency and durability of the organic light emitting devices produced thereof, and why cis‐configurated halide‐bearing vinylene moieties should be perceived as being among the most critical candidates. These considerations result in the recommendation of straightforward measures that should lead to clearly improved PPVs.

     

Synthesis of 23-ketocholestane derivatives with different side-chain lengths (asterosapogenin analogs)

Syntheses were developed for 23-ketoasterosapogenin analogs with various sidechain lengths from dimethyl(tert-butyl)silyloxypregnenolone (DMTBS-pregnenolone) through 20-hydroxy-23-carboxylates or 22-acetylenic (C₅, C₆) derivatives by reduction and allylic rearrangement with concurrent oxidation of the intermediate 23-hydroxy-27-nor- and 27-nor-26-methylcholestanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 965–969, April, 1991.     

Poly‐(p‐phenylene vinylenes) with pendent 2,4‐difluorophenyl and fluorenyl moieties: Synthesis,characterization, and device performance

To improve efficiency, processability, and stability, three novel poly‐(p‐phenylene vinylenes) (PPVs) derivatives ( P _a , P _b , and P _c ) with pendent 2,4‐difluorophenyl and fluorenyl moieties were synthesized via Gilch reaction. Their structures were characterized by ¹H NMR, ¹³C NMR, and ELEM. ANAL . Compared with those of PPV and MEH‐PPV, the absolute quantum efficiencies of these polymers showed remarkable improvement (measured at 38.7, 37.2, and 20.3%, respectively), which can be attributed to the presence of twisted multiaryl segments and fluorine atoms. TGA revealed that the inflection temperatures of their thermal decomposition curves were above 400 °C. Double‐layered electroluminescent devices with these polymers as light‐emitting layers [ITO/PEDOT:PSS/Polymer/Ba/Al] showed peak emissions at 493/515, 503, and 600 nm and maximum luminance of 2700, 450, and 4700 cd/m² for P _a , P _b , and P _c , respectively, with onset voltages of ～4 V. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2500–2508, 2009     

Synthesis,Characterization, and Properties of [4]Cyclo‐2,7‐pyrenylene: Effects of Cyclic Structure on the Electronic Properties of Pyrene Oligomers

A cyclic tetramer of pyrene, [4]cyclo‐2,7‐pyrenylene ([4]CPY), was synthesized from pyrene in six steps and 18 % overall yield by the platinum‐mediated assembly of pyrene units and subsequent reductive elimination of platinum. The structures of the two key intermediates were unambiguously determined by X‐ray crystallographic analysis. DFT calculations showed that the topology of the frontier orbitals in [4]CPY was essentially the same as those in [8]cycloparaphenylene ([8]CPP), and that all the pyrene units were fully conjugated. The electrochemical analyses proved the electronic properties of [4]CPY to be similar to those of [8]CPP. The results are in sharp contrast to those obtained for the corresponding linear oligomers of pyrene in which each pyrene unit was electronically isolated. The results clearly show a novel effect of the cyclic structure on cyclic π‐conjugated molecules.     

Synthesis and Properties of 4,5,6-Triphospha[3]radialene

[3]Radialenes: 4,5,6-Tris(2,4,6-tri-tert-butylphenyl)phospha[3]radialene has been synthesized. The compound can be easily handled in air under ambient conditions, despite the [3]radialene moiety containing P?C bonds, and exhibits red-shifted absorption as well as high electron-accepting ability. The unique electronic properties are brought about by the synergistic effect of the [3]radialene framework and the phosphorus substitution.     

反-1,2-双[2-(5-取代苯基恶唑基)]环丙烷的合成与光性能的研究

本文合成了8个反-1,2-双[2-(5-取代苯基恶唑基)]环丙烷和2个1,2-双[2-(5-取代苯基恶唑基)]乙烷,其中9个为新化合物。讨论了化合物的结构与其电子光谱及荧光量子产率间的关系。我们发现恶唑环与三元环间存在一定程度的共轭,并解释了上述化合物荧光量子产率较低的现象。     

Synthesis and fractionation of poly(phenylene methylene)

Poly(phenylene methylene) (PPM) was isolated in a broad range of molar masses by optimization of the catalytic polymerization of benzyl chloride with SnCl₄ or FeCl₃, followed by fractionation by Soxhlet extraction or phase separation in concentrated solutions in poor solvents. Low molar mass products were also obtained by quenching the reaction at moderate monomer conversions. Products with number average molar masses (M_n) ranging from 200 to 61,000 g mol⁻¹ were isolated, the latter being an order of magnitude above the previously reported values. DSC analysis of polymers of different molar masses revealed that the glass transition temperature follows the Flory‐Fox equation reaching a plateau value of 65 °C at a molar mass between 10,000 and 20,000 g mol⁻¹. The onset of decomposition temperature of higher molar mass products proceeds above 450 °C (maximum decomposition rate at 515 °C), according to TGA. Furthermore, the substitution pattern of PPM was discussed by study of chemical shifts of the methylene group by extensive NMR spectroscopy (¹H, ¹³C, DEPT, and HSQC) and by comparison with two mono‐substituted derivatives of PPM—poly(2,4,6‐trimethylphenylene methylene) and poly(2,3,5,6‐tetramethylphenylene methylene)—which were synthesized analogous to PPM. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 309–318     

Stereocontrolled synthesis and optical properties of all-cis poly(phenylene vinylenes) (PPVs): a method for direct patterning of PPVs

Geometrically pure, all-cis poly(phenylene vinylenes) (PPVs) are synthesized by Suzuki-Miyaura-type polycondensation of 2,5-dioctyloxy-1,4-benzenediboronic acid with (Z,Z)-bis(2-bromoethenyl)benzenes, which are prepared by ruthenium-catalyzed (Z)-selective double hydrosilylation of diethynylbenzenes, followed by bromodesilylation of the resulting (Z,Z)-bis(2-silylethenyl)benzenes with N-bromosuccinimide. The all-cis PPVs thus obtained undergo one-way photoisomerization to the corresponding trans-PPVs both in solution and in the solid. This phenomenon is applied to direct microscale patterning of PPVs onto a quartz substrate.     

Synthesis,structural, and spectral characterization of Keggin-type mono cobalt(II)-substituted phosphotungstate

Keggin-type mono Co(II)-substituted phosphotungstate was synthesized from 12-tungstophosphoric acid and cobalt chloride tetrahydrate. The obtained complex was systematically characterized in solution as well as solid by various physicochemical techniques. A single-crystal X-ray analysis shows that the complex crystallizes in tetragonal system, P4₂/ncm space group with a?=?b?=?20.9860(5)?Å, c?=?10.4368(3)?Å, and Z?=?4. The crystal showed two types of disorders related by center of symmetry. Structural studies did not show the presence of Co, but the incorporation of the metal ion was proved by various spectral techniques. Spectral as well as electrochemical studies confirmed the presence of Co(II) into the lacunary position of the phosphotungstate moiety.     

给、吸电子基团对芳香共轭体系电子结构影响的密度泛函理论研究

采用密度泛函理论,在B3LYP／6—31G^＊方法水平上对8个连接有给、吸电子基团的芳香共轭体系的稳定性、偶极矩、静电荷分布和前线轨道能级进行了研究,并采用TD／DFT方法进一步研究了它们的电子光谱．结果表明a-1,b-1,c-1和d-2分子比它们的同分异构体要稳定;对于苯、呋喃、吡咯与乙烯形成的共轭体系,吸电子基团连接在乙烯一端,给电子基团连接在芳香环上使体系的偶极距增强,而吡啶则相反;前线轨道能级差较小的是吸电子基团连接在芳香环一端的体系,相应的分子最大吸收波长也较大．     

Copper(II) and cobalt(II) hydroxypyridinecarboxylates: Synthesis, crystal structures, spectral and magnetic properties

Synthesis and characterization of six copper(II) and cobalt(II) octahedral complexes [M(6-OHpic)₂(H₂O)₂] (6-OHpic is 6-hydroxypicolinato), [M(2-OHnic)₂(H₂O)₂] (2-OHnic is 2-hydroxynicotinato), [Cu(6-OHnic)₂(H₂O)₂] (6-OHnic is 6-hydroxynicotinato) as well as [Co(H₂O)₆](6-OHnic)₂ are reported. Their characterization was carried out using elemental analysis, infrared, and magnetic measurements. Based on IR spectra, N,O-coordination of 6-OHpic (via the oxygen atom of the carboxyl group and the nitrogen atom of the pyridine ring), O,O-asymmetrically chelating coordination of the carboxyl groups as well as ionic coordination of 6-OHnic and chelating O,O-coordination (through the oxygen atom of the carboxyl group and the oxygen atom of the amide group) of keto(amide) tautomer of 2-OHnic were supposed. Moreover, crystal structures of 2-OHnicH and the complex [Co(2-OHnic)₂(H₂O)₂]) were determined by X-ray single crystal structure analysis. The system of hydrogen bonds predominantly stabilizes the keto(amide) tautomer of both 2-hydroxynicotinic acid and 2-OHnic anion in the cobalt(II) complex. Intermolecular hydrogen bonds (between the oxygen atom of the amide group and the hydrogen atom of the NH group) interconnect two neighbouring molecules of 2-OHnicH forming dimers. Cobalt(II) in complex [Co(2-OHnic)₂(H₂O)₂] has nearly a regular compressed tetragonal bipyramidal arrangement. Presented at the 1st International Conference “Applied Natural Sciences” on the occasion of the 10th anniversary of the University of Ss. Cyril and Methodius, Trnava, 7–9 November 2007.