Polymers with alternating anthracene and phenylene building blocks linked by ethynylene and/or vinylene units: Studying structure‐properties‐relationships

Four conjugated polymers ( P1 – P4 ) consisting of alternating anthracene‐9,10‐diyl and 1,4‐phenylene building blocks connected via ethynylene as well as vinylene ( P1 and P2 ), ethynylene‐only ( P3 ), and vinylene‐only ( P4 ) moieties, respectively, were synthesized and studied. The phenylene units in all four polymers bear 2‐ethylhexyloxy side‐chains to promote good solubility. The three polymers with vinylene units ( P1 , P2 , and P4 ) were prepared using the Horner–Wadsworth–Emmons reaction. For the synthesis of the arylene‐ethynylene polymer P3, the palladium‐catalyzed Sonogashira cross‐coupling reaction was used. The polymers were characterized by NMR, Fourier transform infrared spectroscopy, and Raman spectroscopy. Photophysical, absorption and photoluminescence, and electrochemical properties were studied. Spectroscopic ellipsometry measurements were performed to gain more insight on the optical properties. In addition, the transport properties were investigated using admittance spectroscopy. The bulk hole mobility and its dependence on the electric field were evaluated for P1 and P2 . © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 129–143     

Synthesis,structure, and optical properties of an alternating calix[4]arene‐based meta‐linked phenylene ethynylene copolymer

Novel alternating copolymers comprising bis‐ calix[4]arene‐p‐phenylene ethynylene and m‐phenylene ethynylene units ( CALIX‐m‐PPE ) were synthesized using the Sonogashira‐Hagihara cross‐coupling polymerization. Good isolated yields (60–80%) were achieved for the polymers that show M_n ranging from 1.4 × 10⁴ to 5.1 × 10⁴ gmol^?1 (gel permeation chromatography analysis), depending on specific polymerization conditions. The structural analysis of CALIX‐m‐PPE was performed by ¹H, ¹³C, ¹³C–¹H heteronuclear single quantum correlation (HSQC), ¹³C–¹H heteronuclear multiple bond correlation (HMBC), correlation spectroscopy (COSY), and nuclear overhauser effect spectroscopy (NOESY) in addition to Fourier transform‐Infrared spectroscopy and microanalysis allowing its full characterization. Depending on the reaction setup, variable amounts (16–45%) of diyne units were found in polymers although their photophysical properties are essentially the same. It is demonstrated that CALIX‐m‐PPE does not form ground‐ or excited‐state interchain interactions owing to the highly crowded environment of the main‐chain imparted by both calix[4]arene side units which behave as insulators inhibiting main‐chain π–π staking. It was also found that the luminescent properties of CALIX‐m‐PPE are markedly different from those of an all‐p‐linked phenylene ethynylene copolymer ( CALIX‐p‐PPE ) previously reported. The unexpected appearance of a low‐energy emission band at 426 nm, in addition to the locally excited‐state emission (365 nm), together with a quite low fluorescence quantum yield (? = 0.02) and a double‐exponential decay dynamics led to the formulation of an intramolecular exciplex as the new emissive species. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

带内取向柔性多醚链苯炔大环合成

采用分子间Glaser半环闭环法合成了带内取向柔性多醚链的苯炔大环.用1H NMR,13C NMR,HRMS,UV及PL(photduminescence)确证了目标大环结构,凝胶色谱测定了目标大环纯度.经偏光显微镜(POM)和差热分析仪(DSC)测试表明大环没有呈现预期的液晶性质,可能是由于环内柔性链过于拥挤,不能形成与环平面共面结构,以至于难于进行有序堆积的缘故.     

Aggregation-induced emission enhancement in poly(phenylene-ethynylene)s bearing aniline groups

Poly(phenylene ethynylene)s(P1) with 4-vinylaniline pendant groups were successfully prepared by the Sonogashira coupling polymerization between l,4-diethynyl-2,5-bis(pentyloxy)benzene and 4-[2-(2,5-dibromophenyl)vinyl]-aniline. In comparison with its analogue P2 without amino group,the emission of P1 is only enhanced by aggregation when adding n-hexane into its THF solution,exhibiting an aggregation-induced emission enhancement(AIEE) effect.When methanol or water instead of hexane was added into THF solution,P1,however,didn’t show AIEE.The results indicated that amino groups strengthen the inter-chain and intra-chain interactions in P1 and restrict the non-radiative energy transition. This strategy can provide a platform for developing highly sensitive and efficient bio- and chemosensors.     

5，8-二呋喃基萘基喹喔啉与对苯撑乙炔交替共聚物的合成及其性能

利用Stille耦合反应合成了新型单体5,8-二呋喃基萘基喹喔啉,溴化后与不同长链烷氧基侧链的对苯撑乙炔共聚,合成了聚[2,5-二（辛氧基）-1,4苯撑乙炔撑-5,8-二（呋喃基）萘基喹喔啉]（PⅠ）和聚[2,5-二（十二烷氧基）-1,4-苯撑乙炔撑-5,8-二（呋喃基）萘基喹喔啉]（PⅡ）。通过FT—IR、1H—NMR等手段对单体和共聚物的结构进行了表征,采用紫外-可见吸收光谱、荧光发射光谱和循环伏安法对聚合物的光、电性能进行了探讨。结果表明：单体和共聚物PⅠ、PⅡ在长波处的紫外-可见吸收峰分别为435、418、423nm,相应的荧光发射峰分别为551、589、579nm。2种共聚物均在1．54V处出现氧化峰,无相应的还原峰。     

Synthesis and characterization of alternative donor-acceptor arranged poly(arylene ethynylene)s derived from 1,4-diketo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP)

A series of donor-acceptor type poly(arylene ethynylene)s (PAEs) have been synthesized through Sonogashira polycondensation. The polymers consist of an electron donating 9,9-bis(2-ethylhexyl)-9H-fluorene, triphenylamine, 1,4-dialkoxybenzene or 9-(2-ethylhexyl)-9H-carbazole unit and an electron accepting 2,5-bis(2-ethylhexyl)-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (EH-DPP) unit, alternately connected through ethynyl bridge. The polymers exhibit weight-average molecular weights (M_w) up to 68, 500 and are soluble in chlorobenzene, dichlorobenzene, THF, chloroform and toluene. A brilliant red solution with absorption maxima between 491 and 500 nm was observed for all the polymers. An intense red fluorescent with photoemission maxima between 551 and 571 nm was observed from polymer solutions. The polymers showed good thermal stability with decomposition temperature more than 260 °C at 5% weight loss. Onset oxidation potentials of the polymers were observed between 1.30 and 1.58 V with HOMO energy levels in the range of −6.10 to −6.38 eV. The OLED devices were fabricated with configuration of ITO/PEDOT:PSS/polymer/LiF/Al for all the polymers and EL maxima between 666 and 684 nm were observed.     

Oligo(p-phenylene-ethynylene)s with backbone conformation controlled by competitive intramolecular hydrogen bonds

A series of conjugated oligo(p-phenylene-ethynylene) (OPE) molecules with backbone conformations (that is, the relative orientations of the contained phenylene units) controlled by competitive intramolecular hydrogen bonds to be either co-planar or random were synthesised and studied. In these oligomers, carboxylate and amido substituents were attached to alternate phenylene units in the OPE backbone. These functional groups were able to form intramolecular hydrogen bonds between neighbouring phenylene units. Thereby, all phenylene units in the backbone were confined in a co-planar conformation. This planarised structure featured a more extended effective conjugation length than that of regular OPEs with phenylene units adopting random orientation due to a low rotational-energy barrier. However, if a tri(ethylene glycol) (Tg) side chain was appended to the amido group, it enabled another type of intramolecular hydrogen bond, formed by the Tg chain folding back and the contained ether oxygen atom competing with the ester carbonyl group as the hydrogen-bond acceptor. The outcome of this competition was proven to depend on the length of the alkylene linker joining the ether oxygen atom to the amido group. Specifically, if the Tg chain folded back to form a five-membered cyclic structure, this hydrogen-bonding motif was sufficiently robust to overrule the hydrogen bonds between adjacent phenylene units. Consequently, the oligomers assumed non-planar conformations. However, if the side chain formed a six-membered ring by hydrogen bonding with the amido NH group, such a motif was much less stable and yielded in the competition with the ester carbonyl group from the adjacent phenylene unit. Thus, the hydrogen bonds between the phenylene units remained, and the co-planar conformation was manifested. In our system, the hydrogen bonds formed by the back-folded Tg chain and amido NH group relied on a single oxygen atom as the hydrogen-bond acceptor. The additional oxygen atoms in the Tg chain made a negligible contribution. A bifurcated hydrogen-bond motif was unimportant. From our results, in combination with the results from an independent study by Meijer et al., it is evident that intramolecular hydrogen bonds involving back-folded oligo(ethylene glycol) moieties may differ in their structural details. Absorption spectroscopy served as a convenient yet sensitive technique for analysing hydrogen-bonding motifs in our study.     

Facile synthesis of ortho‐Phenylene‐based conjugated polymers through transformation of cross‐conjugated poly(2,3‐diaryl[2]dendralene)s and their optical properties

We studied the facile synthesis of ortho‐phenylene‐based conjugated polymers through transformation of cross‐conjugated polymers having [2]dendralene moiety, poly(2,3‐diaryl[2]dendralene)s ( P1 s), and demonstrated the sequential synthesis of (Z)‐alkene‐ and ortho‐arylene‐containing conjugated polymers from P1 s. P1 s were transformed into cyclohexa‐1,4‐diene‐containing conjugated polymers ( P2 s) through a Diels–Alder reaction. Aromatization of the cyclohexa‐1,4‐diene skeleton was achieved by using 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone to give the ortho‐phenylene‐containing conjugated polymers ( P3 s). The ultraviolet–visible and fluorescence spectra of the cross‐conjugated polymers P1 s, and the conjugated polymers P2 s and P3 s indicated that the π–π interactions between the arylene moieties in P2 s were stronger than those in P1 s and P3 s. The synthetic method for P2 s and P3 s offers an effective synthesis of various types of (Z)‐alkene‐ and ortho‐arylene‐containing conjugated polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 827–832