- Synthesis, optical, electrochemical, and thermal properties of conjugated α-fluorenyl oligothiophenes
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A series of new α-fluorenyl oligothiophenes up to the pentamer have been synthesized using Suzuki cross-coupling and bromination reactions. The optical, electrochemical, and thermal properties of these materials can be tuned by varying the number of thiophene rings. The longer oligomers (n ≥ 4) were stable, crystalline, and unreactive to electrochemical oxidative dimerization.
- Promarak, Vinich,Punkvuang, Auradee,Meunmat, Duangratchaneegorn,Sudyoadsuk, Taweesak,Saengsuwan, Sayant,Keawin, Tinnagon
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- Oligofluorenes as polymeric model compounds for providing insight into the triplets of ketone and ketylimine derivatives
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A series of oligofluorenes ranging between one and three repeating units were prepared as structurally well-defined representative models of polyfluorenes. The photophysics of the oligofluorene models were investigated both by laser flash photolysis and steady-state fluorescence. The effects of the ketone and ketylimine functional groups in the 9-position on the photophysical properties, notably the triplet quantum yield (ΦTT) by intersystem crossing and the absolute fluorescence quantum yields (Φfl), were investigated. The singlet depletion method was used to determine both the ΦTT and molar absorption coefficients of the observed triplets (εTT). Meanwhile, the absolute Φfl were determined using an integrating sphere. It was found that both the ketone and ketylimine substituents and the degree of oligomerization contributed to quenching the oligofluorene fluorescence. For example, the Φfl was quenched 5-fold with the ketylimine and ketone substituents for the bifluorenyl derivatives compared to their corresponding 9,9-dihexyl bifluorenyl counterparts. Meanwhile, the Φfl quenching increased 14 times with the trifluorenyl ketone and ketylimine derivatives. Measured ΦTT values ranged between 22 and 43% for the difluorenyl derivatives with εTT on the order of 13 000 cm-1 M-1. The ΦTT decreased to TT when the degree of oligomerization was increased to 3. A new fluorescence emission at 545 nm formed at low temperatures for the ketone and ketylimine oligofluorene derivatives. The emission intensity was dependent on the temperature, and it disappeared at room temperature.
- Robert, Patricia,Bolduc, Andreanne,Skene, W. G.
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- Design of differently P-substituted 4i PO fluorescent tetraphosphonate cavitands
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Experimental approaches to tetraphosphonate cavitands bearing fluorenyl-phosphonate bridges are reported. Different routes are described depending on the substitution on the cavitand structure. Tetra-, tri- and di-bridged phosphonate cavitands have been p
- Mettra, Bastien,Bretonniere, Yann,Mulatier, Jean-Christophe,Bibal, Brigitte,Tinant, Bernard,Aronica, Christophe,Dutasta, Jean-Pierre
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- Amorphous iridium complexes for electrophosphorescent light emitting devices
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Iridium complexes with fluorene-modified phenylpyridine ligands are resistant to crystallization and can be used in the fabrication of single layer light emitting diodes.
- Ostrowski, Jacek C.,Robinson, Matthew R.,Heeger, Alan J.,Bazan, Guillermo C.
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- Photophysical, electrochemical, and crystallographic investigation of conjugated fluoreno azomethines and their precursors
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The photophysical investigation of amino- and aldehyde-substituted fluorenes revealed that these compounds are not only highly fluorescent, but dissipation of their singlet excited energy occurs by a combination of nonradiative means involving intersystem crossing (ISC) and internal conversion (IC). Quantification of the triplet state formed by ISC was possible by laser-flash photolysis (LFP). The efficiency by which this manifold was populated varied between 10 and 40% depending on the fluorene substitution. Condensation of these aldehyde and amine precursors yielded conjugated thiopheno azomethines with robust covalent bonds. Fluorescence of the azomethine fluorene derivatives was reduced relative to their precursors while the degree of IC remained unchanged. Deactivation of the singlet excited state occurred predominately by ISC and the resulting triplet state was rapidly and efficiently quenched by energy transfer by the azomethine linkage. Cyclic voltammetry of the fluoreno azomethines showed both oxidation and reduction processes, and the measured redox potentials and the band-gaps are lower than a bisfluorene analogue. The fluoreno azomethine LUMO energy levels are sufficiently low, making them compatible with common cathodes, therefore eliminating the use of an electron-injection layer. The Royal Society of Chemistry 2007.
- Guarin, Sergio Andres Perez,Dufresne, Stephane,Tsang, Derek,Sylla, Assa,Skene
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- Synthesis, optical and electrochemical properties of 2-[(9H-fluoren-2-yl)aryl]-1H-benz[d]imidazole and 2,7-bis[(1H-benz[d]imidazol-2-yl)aryl]-9H-fluorene derivatives
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A series of 2-[(9H-fluoren-2-yl)aryl]-1H-benzo[d]imidazoles 11-13 and 2,7-bis[(1H-benzo[d]imidazol-2-yl)aryl]-9H-fluorenes 14-16 containing different linking aromatic units were synthesized in good yields. Their absorption and fluorescence properties were
- Li, Qing-Feng,Li, Min-Jie,Lin, Hai-Xia,Xu, Pei-Pei,Gu, Ze-Bin,Cui, Yong-Mei
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- Difluorenyl carbo-Benzenes: Synthesis, Electronic Structure, and Two-Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores
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The synthesis, crystal and electronic structures, and one- and two-photon absorption properties of two quadrupolar fluorenyl-substituted tetraphenyl carbo-benzenes are described. These all-hydrocarbon chromophores, differing in the nature of the linkers b
- Baglai, Iaroslav,De Anda-Villa, Manuel,Barba-Barba, Rodrigo M.,Poidevin, Corentin,Ramos-Ortíz, Gabriel,Maraval, Valérie,Lepetit, Christine,Saffon-Merceron, Nathalie,Maldonado, José-Luis,Chauvin, Remi
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- Synthesis and characterization of N-carbazole end-capped oligofluorenes
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A series of N-carbazole end-capped oligofluorenes (CFn, n = 1-3) were synthesized. The 9-position of the carbazole moiety was attached to the terminal ends of the oligofluorene cores using an Ullmann coupling reaction. These molecules exhibit red shifts in absorption and photoluminescence spectra with respect to the number of fluorene units and excellent electrochemical reversibility. They were found to be potential blue light-emitting or hole-transporting materials for organic light-emitting diodes (OLEDs).
- Promarak, Vinich,Saengsuwan, Sayant,Jungsuttiwong, Siriporn,Sudyoadsuk, Taweesak,Keawin, Tinnagon
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- Two-photon absorption properties of four new pentacoordinated diorganotin complexes derived from Schiff bases with fluorene
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In this paper we report the synthesis and characterization of four novel pentacoordinated diorganotin complexes, obtained through a methodology that involves a multicomponent reaction of 4-([9H-fluorene-2-yl]ethynyl)-2-hydroxybenzaldehyde, 2-amino-5-nitrophenol and diphenyl or dibutyl-tin oxides. Diorganotin complexes 8–11 were obtained in high yields (70–80%) and were fully characterized by solution NMR (1H, 13C and 119Sn), high resolution mass spectrometry (ESI-TOF) and ATR-FTIR. The optical properties were investigated by UV/Vis spectroscopy and Two-Photon Excitation Fluorescence (TPEF). The One-Photon Absorption (OPA) spectra shows two bands located around 400 and 500 nm, additionally, in the Two-Photon Absorption (TPA) spectra there is one main band located around 750 nm characterized by maximum values of TPA cross section (σTPA) in the range 450–500 GM with a secondary band located at 1000 nm with maximum σTPA values of 70 GM; the maximum brightness was observed for 2,2-Dibutyl-6-aza-1,3-dioxa-11-([9,9-dihexyl-9H-fluorene-2-yl]ethynyl)-16-nitro-2-stanna-[d,h]dibenzocyclononene with a value of 150 GM. A theoretical approach within the framework of DFT was applied to study the electronic transitions, showing that the 500 nm band is mainly associated to a HOMO→LUMO transition, and the band at 400 nm to a HOMO-1→LUMO transition. As main highlights the quantum efficiency of fluorescence of these excited states is as large as 0.43 due to the presence of the tin atom which favors molecular rigidity, these compounds possess TPA responses which are significantly enhanced with respect to related organotin chromophores previously reported.
- Enríquez-Cabrera, Alejandro,Vega-Pe?aloza, Alberto,álvarez-Venicio, Violeta,Romero-ávila, Margarita,Lacroix, Pascal G.,Ramos-Ortiz, Gabriel,Santillan, Rosa,Farfán, Norberto
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- Simple fluorene oxadiazole-based Ir(iii) complexes with AIPE properties: Synthesis, explosive detection and electroluminescence studies
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Two novel phosphorescent Ir(iii) complexes, Ir(fom)2(pic) and Ir(fof)2(pic), containing fluorene oxadiazole groups have been synthesized and characterized. The photophysical properties of the complexes have been investigated. Interestingly, both complexes exhibited aggregation-induced phosphorescent emission. The X-ray diffraction study showed that the AIPE properties resulted from weak π-π and C-H?N hydrogen-bonding interactions in the aggregated state restricting the rotation of the phenyl groups in the cyclometalating ligands. Owing to the sensitive and selective luminescence quenching of the complexes using picric acid (PA), the complexes were used for PA detection in aqueous media. Additionally, electroluminescence devices have been fabricated using the complexes at 5%-30% doping concentrations. The devices based on Ir(fof)2(pic) obtained the highest luminance 11877 cd m-2 and current efficiency 23.2 cd A-1, which implied that the incorporation of fluorine could improve the electron affinity and ameliorate the capability of electron injection or transporting.
- Liu, Jia-Wei,Xu, Ya-Nan,Qin, Chun-Yan,Wang, Zi-Ning,Wu, Cong-Jin,Li, Yong-Hua,Wang, Shi,Zhang, Kenneth Yin,Huang, Wei
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- Two-Photon Absorption Properties in “Push-Pull” Ruthenium Nitrosyl Complexes with various Fluorenylterpyridine-Based Ligands
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Using the compound [RuII(FT)(bipy)(NO)](PF6)3 (FT is the electron-rich 4’-(2-fluorenyl)-2,2’:6’,2’’-terpyridine ligand and bipy is 2–2’bipyridine) as a reference, two new compounds are presented in which carbon-carbon double and triple bonds are inserted between the fluorenyl substituent and the terpyridine to provide an extended conjugation path. The electronic properties of the three complexes are compared experimentally by UV-visible spectroscopy and computationally by means of the density functional theory. All of them exhibit a capability for NO release under irradiation on their low-energy transition located in the 400–500 nm range, with a quantum yield around 0.01. Their two-photon absorption (TPA) cross sections are investigated by the Z-scan technique at λ=800 nm. While the reference compound exhibits a cross-section equal to 108 GM, the introduction of double and triple bonds leads to increased cross-sections equal to 131 GM and 150 GM, respectively. These values are discussed in reference to the two-level model in use for “push-pull” dipolar TPA chromophores.
- Bukhanko, Valerii,León-Rojas, Andrés Felipe,Lacroix, Pascal G.,Tassé, Marine,Ramos-Ortiz, Gabriel,Barba-Barba, Rodrigo M.,Farfán, Norberto,Santillan, Rosa,Malfant, Isabelle
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p. 1670 - 1684
(2021/05/03)
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- Arylamino-fluorene derivatives: Optically induced electron transfer investigation, redox-controlled modulation of absorption and fluorescence
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A series of biarylaminofluorene-based systems with donor-π-donor (D-π-D) structure have been designed and synthesized in order to study the dependence on the π-conjugated bridge length of the intervalence charge-transfer transitions (IV-CT) and of the electronic coupling between the redox centers. To this purpose cyclic voltammetry, UV/Vis-NIR, fluorescence spectroscopy and computational investigations have been carried out to characterize the electronic structure of the compounds in the neutral as well as in the mono- and dication states. Additionally, a study of related D-π compounds has been performed to elucidate the effect of the interaction between two redox centers. Interestingly it was observed that the mono- and dication species exhibit intense transition bands in the NIR region, in the 10000-15000 cm?1 range, whose intensity depends on the oxidation state and thus it can be reversibly tuned by an applied potential. In a similar way, all compounds show an oxidation state dependent fluorescence which leads to electrofluorochromism. Particularly significant is the mixed valence behavior that provides these systems singular optoelectronic properties, making them excellent active components for electrochromic and electrofluorochromic applications.
- Accorsi, Gianluca,Beneduci, Amerigo,Capodilupo, Agostina-Lina,Cardone, Antonio,Corrente, Giuseppina Anna,Fabiano, Eduardo,Giannuzzi, Roberto,Gigli, Giuseppe,Manni, Francesca
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- Fluorenyl oxadiazole iridium complex and application thereof
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The invention discloses a fluorenyl oxadiazole iridium complex and application thereof. A structural formula of the fluorenyl oxadiazole iridium complex is as shown in the specification, wherein C isan auxiliary ligand 2-picolinic acid, R2 and R3 are alkyl chains, and R1 is methyl. The prepared complex has good hole transport and electron transport properties, can be applied to the field of organic light emitting diodes (OLED), and is applied to the detection of nitro explosives.
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Paragraph 0035; 0037
(2019/02/27)
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- Fluorenyl oxadiazole iridium complexes, and preparation method and application thereof
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The invention provides fluorenyl oxadiazole iridium complexes, and a preparation method and application thereof. The structural formula of the fluorenyl oxadiazole iridium complexes is as described inthe specification. R in the structural formula is hydrogen or halogen. The complexes use fluorenyl oxadiazole groups as main ligand and 2-picolinic acid as auxiliary ligand. Since the molecules of the complexes contain fluorenyl groups with rigid structure and oxadiazole groups with electron transport characteristics, the complexes have high luminescence efficiency and excellent device performance. The complexes present green-yellow photoluminescent light in a dichloromethane solution, can be applied to yellow-light-emitting, green-light-emitting or white-light-emitting OLED devices, and broaden the selection scope of phosphorescent materials.
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Paragraph 0058; 0059; 0071
(2018/04/03)
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- Fluorenyl tetrazole iridium complexes, and preparation method and application thereof
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The invention provides fluorenyl tetrazole iridium complexes, and a preparation method and application thereof. The structural formula of the fluorenyl tetrazole iridium complexes is as described in the specification. R1 in the structural formula is H or DPA, and R2 in the formula is CH3 or C6H13. The fluorenyl tetrazole iridium complexes are prepared from cyclometalated ligand, metal centers andthe auxiliary ligand picolinic acid. The fluorenyl tetrazole iridium complexes have long luminescence life, mild synthesis reaction conditions and good market application prospects.
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Paragraph 0073; 0074
(2018/04/03)
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- Fluorenyl oxadiazole-based iridium complex as well as preparation and application method
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The invention discloses a fluorenyl oxadiazole-based iridium complex as well as a preparation and application method. The complex has a structural formula shown in the specification. In a preparationprocess, expected main ligand is prepared from a derivative of benzoyl chloride of which positions C2 and C6 are occupied by substituent groups without coordination properties, so that the obtained main ligand has only one coordination mode with a central iridium atom, the prepared iridium complex forms a crystal structure with relatively good homogeneity under the action of molecules, the formedcrystal has very good crystal surface ductility and is applicable to piezochromism materials.
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Paragraph 0043; 0045
(2018/10/19)
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- Hexyl substituted - fluorenylmethylchloroformate modified aryl imidazole compound, preparation method and its darkblue photoelectric electroluminescent device (by machine translation)
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The invention belongs to the organic light-emitting material and its photoelectric device application technology field, in particular to hexyl substituted - fluorenylmethylchloroformate modified aryl imidazole compound, preparation method and its darkblue photoelectric electroluminescent device. The invention provides a hexyl substituted - fluorenylmethylchloroformate modified aryl imidazole compounds and its preparation method, the substituted states the hexyl - fluorenylmethylchloroformate modified aryl imidazole compound of the general formula formula I structure. The invention also provides based on hexyl substituted - fluorenylmethylchloroformate modified aryl imidazole compound can be efficient transmitting deep-blue light-emitting electroluminescent device, solves the difficult to give consideration to the prior art high blue light purity and connects escape efficiency the technical problem of, by means of the imidazole material with hexyl fluorene fine characteristic, synthetic which has both a high soluble, high blue light purity and a high fluorescence quantum yield of the organic light-emitting small molecule and its dark blue light organic electroluminescent device. (by machine translation)
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Paragraph 0056; 0057; 0058; 0059; 0071; 0072; 0073
(2018/07/15)
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- Efficient Color-Tunable Copper(I) Complexes and Their Applications in Solution-Processed Organic Light-Emitting Diodes
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A series of dppnc- and neocuproine-based CuI complexes (dppnc=7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate) are synthesized and the emission color of these CuI complexes can be tuned from green to deep red via rational modification of the neocuproine ligand structure. The molecular structures of the emissive CuI complexes, Cu(dppnc)-G (green emitting), Cu(dppnc)-Y (yellow emitting), and Cu(dppnc)-R (red emitting), are characterized and their electronic structures and related transition properties are elucidated by photo-physical and computational (density functional theory) studies. The calculation results suggest that thermally activated delayed fluorescence (TADF) is the emission mechanism for these CuI complexes. Efficient solution-processed green-, yellow-, and red-emitting OLEDs are fabricated based on the emissive complexes as the dopants. High external quantum efficiency (EQE) of 15.20 % and current efficiency of 48.15 cd A?1 at 1000 cd m?2 are achieved in the green-emitting device with Cu(dppnc)-G. A maximum EQE of 10.17 %, CIE coordinates of (0.61, 0.38) and a maximum electroluminescent peak of 631 nm are achieved in the red device based on Cu(dppnc)-R.
- So, Gary Kwok-Ming,Cheng, Gang,Wang, Jian,Chang, Xiaoyong,Kwok, Chi-Chung,Zhang, Hongxing,Che, Chi-Ming
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supporting information
p. 1490 - 1498
(2017/07/11)
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- One on the basis of [...]high fused ring of [6] spiral alkene compound and its synthesis method
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The invention provides a kind of highly condensed ring [6]helicene compounds (I) based on fluorene and naphthalene and synthetic method thereof, and belongs to the technical field of chemical engineering. The highly condensed ring [6]helicene compounds with photoelectric functions are successfully prepared by taking naphthalene and fluorene derivatives as raw materials and employing a photocatalytic cyclization method. The synthetic method has the advantages of high yield, short time, simple operation and the like, also employs common cheap reagents, helps to reduce preparation cost, and is easy for popularization and application. The highly condensed ring [6]helicene compounds based on fluorene and naphthalene has extremely good solubility in different organic solvents, and are beneficial for purification and film making. Multiple highly condensed ring [6]helicene compounds can be obtained by introducing different substitutes. The highly condensed ring [6]helicene compounds based on fluorene and naphthalene is hopeful to be widely applied to fields such as organic electroluminescence, Organic field effect transistor, organic second-order nonlinear or chiral liquid crystal, biological medicines and the like.
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Paragraph 0065; 0068
(2017/09/02)
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- Synthesis and properties of dicarbazolyltriphenylethylene-substituted fluorene derivatives exhibiting aggregation-induced emission enhancement
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Two novel dicarbazolyltriphenylethylene-substituted fluorene derivatives DctF and Dct2F were synthesized by the Wittig-Horner and Suzuki coupling reactions. It was reasoned that introducing linear alkyl chains into the fluorene structure could facilitate the deposition of high-quality films by an economical and simple process. The thin solid films of DctF and Dct2F show strongly enhanced emissions in comparison to their dilute solutions, which indicate the aggregation-induced emission enhancement (AIEE). Their decomposition temperatures (Td) exceed 400°C and the glass transition temperature (Tg) of DctF is 105°C. The maximum fluorescence emission wavelengths are in the region of 458-469 nm.
- Zhang, Qiang,Huang, Tian,He, Xing,Zhao, Zhuo-Ran,Zhao, Xin
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- Molecular Engineering of UV/Vis Light-Emitting Diode (LED)-Sensitive Donor–π–Acceptor-Type Sulfonium Salt Photoacid Generators: Design, Synthesis, and Study of Photochemical and Photophysical Properties
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A series of donor–π–acceptor-type sulfonium salt photoacid generators (PAGs) were designed and synthesized by systematically changing electron-donating groups, π-conjugated systems, electron-withdrawing groups, and the number of branches through molecular engineering. These PAGs can effectively decompose under UV/Vis irradiation from a light-emitting diode (LED) light source because of the matching absorption and emitting spectra of the LEDs. The absorption and acid-generation properties of these sulfonium salts were elucidated by UV/Vis spectroscopy and so forth. Results indicated that the PAG performance benefited from the introduction of strong electron-donating groups, specific π-conjugated structures, certain electron-withdrawing groups, or two-branched structures. Most sulfonium salts showed potential as photoinitiators under irradiation by a wide variety of UV and visible LEDs.
- Wu, Xingyu,Jin, Ming,Xie, Jianchao,Malval, Jean-Pierre,Wan, Decheng
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supporting information
p. 15783 - 15789
(2017/10/20)
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- Ligand Engineering for the Efficient Dye-Sensitized Solar Cells with Ruthenium Sensitizers and Cobalt Electrolytes
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Over the past 20 years, ruthenium(II)-based dyes have played a pivotal role in turning dye-sensitized solar cells (DSCs) into a mature technology for the third generation of photovoltaics. However, the classic I3-/I- redox couple limits the performance and application of this technique. Simply replacing the iodine-based redox couple by new types like cobalt(3+/2+) complexes was not successful because of the poor compatibility between the ruthenium(II) sensitizer and the cobalt redox species. To address this problem and achieve higher power conversion efficiencies (PCEs), we introduce here six new cyclometalated ruthenium(II)-based dyes developed through ligand engineering. We tested DSCs employing these ruthenium(II) complexes and achieved PCEs of up to 9.4% using cobalt(3+/2+)-based electrolytes, which is the record efficiency to date featuring a ruthenium-based dye. In view of the complicated liquid DSC system, the disagreement found between different characterizations enlightens us about the importance of the sensitizer loading on TiO2, which is a subtle but equally important factor in the electronic properties of the sensitizers.
- Aghazada, Sadig,Gao, Peng,Yella, Aswani,Marotta, Gabriele,Moehl, Thomas,Teuscher, Jo?l,Moser, Jacques-E.,De Angelis, Filippo,Gr?tzel, Michael,Nazeeruddin, Mohammad Khaja
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supporting information
p. 6653 - 6659
(2016/07/19)
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- Benzobisoxazole cruciforms: A tunable, cross-conjugated platform for the generation of deep blue OLED materials
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Four new cross-conjugated small molecules based on a central benzo[1,2-d:4,5-d′]bisoxazole moiety possessing semi-independently tunable HOMO and LUMO levels were synthesized and the properties of these materials were evaluated experimentally and theoretically. The molecules were thermally stable with 5% weight loss occurring well above 350 °C. The cruciforms all exhibited blue emission in solution ranging from 433-450 nm. Host-guest OLEDs fabricated from various concentrations of these materials using the small molecule host 4,4′-bis(9-carbazolyl)-biphenyl (CBP) exhibited deep blue-emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15 ≤ x ≤ 0.17, 0.05 ≤ y ≤ 0.11), and maximum luminance efficiencies as high as ~2 cd A-1. These results demonstrate the potential of benzobisoxazole cruciforms as emitters for developing high-performance deep blue OLEDs.
- Chavez, Ramiro,Cai, Min,Tlach, Brian,Wheeler, David L.,Kaudal, Rajiv,Tsyrenova, Ayuna,Tomlinson, Aimée L.,Shinar, Ruth,Shinar, Joseph,Jeffries-El, Malika
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supporting information
p. 3765 - 3773
(2016/05/24)
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- Bipolar micromolecular luminescent material based on 4-(9H-carbazole-9-yl) aniline and preparation method and application thereof
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The invention discloses a bipolar micromolecular luminescent material based on 4-(9H-carbazole-9-yl) aniline and a preparation method and application thereof. The material is mainly characterized in that the 4-(9H-carbazole-9-yl) aniline is used as a hole transport center unit, and bipolar micromolecules with the 4-(9H-carbazole-9-yl) aniline as the center are obtained by selecting groups with an electron transmission function. The bipolar micromolecules prepared through the method can be used for making a luminescent layer of an organic light emitting diode.
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Paragraph 0058; 0059; 0060
(2016/10/09)
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- Fluorene-based novel highly emissive fluorescent molecules with aggregate fluorescence change or aggregation-induced emission enhancement characteristics
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A series of luminogens containing formamide or fluorenone units, based on fluorene, have been synthesized and characterized by NMR spectroscopy, mass spectrometry and elemental analysis. Their aggregate fluorescence change and aggregation-induced emission enhancement (AIEE) characteristics were investigated by luminescence and UV/Vis spectroscopies. The results indicate that luminogens 1d and 2d, containing formamide units, exhibit significant fluorescence color changing upon aggregate formation, which is a newly observed uncommon and interesting aggregation-induced emission phenomenon. Although the luminogen 3d, with one fluorenone unit and one fluorene unit, was weakly emissive in solution, it was highly fluorescent in the aggregated state and demonstrates typical AIEE characteristics. In comparison with 3d, the luminogen 4d with one fluorenone unit and two fluorene units showed weaker AIEE behavior. In thin-films and in the solid state, luminogen 1d shows intense yellow-green emission, and other luminogens show strong yellow emitting. Among these luminogens, 4d exhibits the highest solid-state emission quantum yield.
- Chen, Zhao,Liang, Jinhua,Han, Xie,Yin, Jun,Yu, Guang-Ao,Liu, Sheng Hua
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- Chiral Ru/Ir bimetallic dendronized polymer catalysts constructed through sequential metal coordination and applied in asymmetric hydrogenation of quinaldine
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A new kind of chiral conjugated copolymer P-2 with (S)-BINAP [BINAP = 2,2′-bis(diarylphosphino)-1,1′-binaphthyl] and fluorene as the building blocks was synthesized involving Pd[P(p-tolyl)3] 3-catalyzed Suzuki-coupling reaction together with reduction of phosphine oxide with HSiCl3/NEt3. The chiral polymer was used to construct chiral Ru/Ir bimetallic dendronized polymer catalysts P-5-m with different generations of Fréchet-type dendritic DPEN [DPEN = 1,2-diphenylethylenediamine] ligands through a programmed metal-ligand coordination strategy. These dendronized polymer catalysts were applied to the Ir-catalyzed asymmetric hydrogenation of quinaldine and exhibited excellent activity with moderate enantioselectivity. The reaction rate was increased with increasing generation of the dendronized polymer catalysts, which are better than that obtained from the monomeric catalyst. This interesting positive dendrimer effect might be due to effective shielding of the catalytically active iridium center by the bulky dendritic pendants, which reduced the formation of the inactive iridium dimer.
- Huang, Yi-Yong,Yang, Xing,Feng, Yu,Verpoort, Francis,Fan, Qing-Hua
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p. 150 - 155
(2014/07/21)
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- Extreme tuning of redox and optical properties of cationic cyclometalated iridium(III) isocyanide complexes
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We report seven heteroleptic cationic iridium(III) complexes with cyclometalating N-arylazoles and alkyl/aryl isocyanides, [(C aN)2Ir(CNR)2](CF3SO 3), and characterize two of them by crystal structure analysis. The complexes are air- and moisture-stable white solids that have electronic transitions at very high energy with absorption onset at 320-380 nm. The complexes are difficult to reduce and oxidize; they exhibit irreversible electrochemical processes with peak potentials (against ferrocene) at -2.74 to -2.37 V (reduction) and 0.99-1.56 V (oxidation) and have a large redox gap of 3.49-4.26 V. The reduction potential of the complex is determined by the azole heterocycle (pyrazole or indazole) and by the isocyanide (tert-butyl or 2,6-dimethylphenyl) and the oxidation potential by the Ir-aryl fragment [aryl = 2′,4′-R2-phenyl (R = H/F), 9′,9′-dihexyl- 2′-fluorenyl]. Three of the complexes exhibit phosphorescence in argon-saturated dichloromethane and acetonitrile solutions at room temperature with 0-0 transitions at 473-478 nm (green color; the emission spectra are solvent-independent), quantum yields of 3-25%, and long excited-state lifetimes of 62-350 μs. All of the complexes are phosphorescent at 77 K with 0-0 transitions at 387-474 nm (blue to green color). The extremely long calculated radiative lifetimes, 0.5-3.5 ms, confirm that the complexes emit from a cyclometalating-ligand-centered excited state.
- Shavaleev, Nail M.,Monti, Filippo,Scopelliti, Rosario,Baschieri, Andrea,Sambri, Letizia,Armaroli, Nicola,Graetzel, Michael,Nazeeruddin, Mohammad K.
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supporting information
p. 460 - 467
(2013/03/14)
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- Tuning two-photon absorption cross-sections for triphenylamine derivatives
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A methylene bridge link connecting the ortho-positions within the triphenylamine scaffold increases the molecular planarity significantly. The one-photon spectroscopies of bridged triphenylamine molecules show considerable extended conjugation relative to their triphenylamine counterparts, leading to enhanced two-photon absorption (TPA) cross-sections. Various substituents at the scaffold have been prepared and studied. Using a femtosecond laser source Z-scan method, the TPA cross-sections were characterized. The maximum magnitude of the TPA cross-section is ~4800 GM, which is four times that of its triphenylamine counterpart. The Royal Society of Chemistry.
- Fang, Zhen,Webster, Richard D.,Samoc, Marek,Lai, Yee-Hing
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p. 17914 - 17917
(2013/10/01)
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- Synthesis and fluorescent properties of conjugated copolymers containing maleimide and fluorene units at the main chain
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Yamamoto or Suzuki-Miyaura coupling polymerizations of 2,3-diiodo-N- cyclohexylmaleimide with fluorene derivatives (2,7-dibromo-9,9′- dihexylfluorene and 9,9′-dihexylfluorene-2,7-diboronic acid) were carried out. The number-average molecular weights (Mn) of the resulting copolymers were 2600-3500 by gel permeation chromatography analysis. The fluorescence emission of the alternating copolymer showed the emission maxima at 551 nm in THF. On the other hand, the random copolymers showed the bimodal emission peaks at 418-420 and 555-557 nm region, respectively. The fluorescence peaks of the random copolymers on the long wavelength region (555-557 nm) were attributed to the conjugated neighboring N-cyclohexylmaleimide-9,9′- dihexylfluorene units in the polymer main chain. Furthermore, the copolymers exhibited the fluorescence solvatochromism by the difference of the polarity of solvents. The alternating and random copolymers showed the different fluorescence solvatochromism, and the emission colors are distinguishable by the naked eye, respectively. Copyright
- Nakamura, Munetoshi,Yamabuki, Kazuhiro,Oishi, Tsutomu,Onimura, Kenjiro
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p. 4945 - 4956
(2013/11/06)
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- ORGANIC AMBIPOLAR LIGHT EMITTING MATERIALS
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The present invention provides a blue light emitting compound comprising (1) a hole transporting core portion, which hole transporting core portion comprises a tertiary nitrogen portion; and (2) at least three electron transporting arm portions extending from the core portion, each electron transporting arm portion comprising an electron transporting portion and an emissive portion.
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Page/Page column 65
(2011/02/24)
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- Alternating copolymers incorporating cyclopenta[2,1-b:3,4-b′] dithiophene unit and organic dyes for photovoltaic applications
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We have synthesized six p-type copolymers, CPDT-co-TPADCN, CPDT-co-TPADTA, CPDT-co-TPATCN, CPDT-co-DFADCN, CPDT-co-DFADTA, and CPDT-co-DFATCN, consisting of a cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) unit and an organic dye in an alternating arrangement
- Cheng, Yen-Ju,Hung, Lung-Chang,Cao, Fong-Yi,Kao, Wei-Shun,Chang, Chih-Yu,Hsu, Chain-Shu
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experimental part
p. 1791 - 1801
(2012/02/04)
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- Facile C?H alkylation in water: Enabling defect-free materials for optoelectronic devices
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A facile method for the alkylation of fluorene achieved via direct C?H alkylation under aqueous conditions is reported, wherein the formation of fluorenone is inhibited, resulting in the exclusive formation of the desired dialkyl-substituted fluorene monomer. As a proof of concept, this method has also been successfully extended to perform N-alkylation of carbazole, diphenylamine, and N,N-dialkylation of aniline in high yields.
- Saikia, Gunin,Iyer, Parameswar K.
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supporting information; experimental part
p. 2714 - 2717
(2010/07/17)
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- Synthesis, photophysical and electrophosphorescent properties of fluorene-based platinum(II) complexes
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A series of platinum(II) complexes bearing tridentate cyclometalated C^N^N (C^N^N=6-phenyl-2,2'-bipyridine and π-extended R-C^N^N=3-[6'-(naphthalen-2''- yl)pyridin-2'-yl]isoquinoline) ligands with fluorene units have been synthesised and their photophysic
- Yuen, Mai-Yan,Kui, Steven C. F.,Low, Kam-Hung,Kwok, Chi-Chung,Chui, Stephen Sin-Yin,Ma, Chun-Wah,Zhu, Nianyong,Che, Chi-Ming
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supporting information; experimental part
p. 14131 - 14141
(2011/02/23)
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- Metal ion detection by luminescent 1,3-bis(dimethylaminomethyl) phenyl receptor-modified chromophores and cruciforms
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Chromophores ranging from simple small molecule π-conjugated systems comprised of phenylene ethynylene or fluorenylethynyl units to cross-conjugated Bunz-type cruciforms have been derivatized to include 1,3- bis(dimethylaminomethyl)phenyl moieties. The photophysical responsiveness of these diamino-substituted chromophores to metal ions has been examined. Both emission enhancement (turn-on) and ratiometric fluorescence detection of Cu 2+ and Zn2+ ions have been achieved in THF.
- Mangalum, Anshuman,Gilliard Jr., Robert J.,Hanley, Jessica M.,Parker, Austa Marie,Smith, Rhett C.
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supporting information; experimental part
p. 5620 - 5627
(2011/02/18)
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- Cyclometalated platinum(II) 6-phenyl-4-(9,9-dihexylfluoren-2-yl)-2, 2′-bipyridine complexes: Synthesis, photophysics, and nonlinear absorption
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A series of mononuclear and dinuclear cyclometalated platinum(II) 6-phenyl-4-(9,9-dihexylfluoren-2-yl)-2,2′-bipyridine complexes (F-1-F-5) were synthesized and their photophysical properties were systematically investigated. All complexes exhibit strong 1π, π*absorption bands in the UV region, and a broad, structureless charge transfer band in the visible region. The charge-transfer band is broadened and red-shifted for F-3-F-5 compared to those for F-1 and F-2 because of the electron-donating acetylide ligand and the involvement of the ligand-to-ligand charge transfer character. The molar extinction coefficients for the dinuclear complex F-5 are much higher than those for the mononuclear complexes F-1-F-4, indicating the electronic coupling through the bridge ligand. All complexes are emissive in solution at room temperature and in glassy matrix at 77 K. When excited at the charge transfer absorption band, the complexes exhibit a long-lived red/orange emission around 600 nm, which is attributed to a triplet metal-to-ligand charge transfer/intraligand charge transfer emission ( 3MLCT/3ILCT). For emission at 77 K, the emitting state is tentatively assigned as 3MLCT for F-2-F-4, and 3MLCT/ 3π,π*for F-1 and F-5 taking into account the emission energy, the shape of the spectrum, the lifetime, and the thermally induced Stokes shift. F-1-F-4 exhibit broad triplet transient difference absorption in the visible to the near-IR region, with a lifetime comparable to those measured from the decay of the 3MLCT/3ILCT emission. Therefore, F-1-F-4 give rise to a strong reverse saturable absorption for ns laser pulses at 532 nm. Z-scan experiments were carried out at 532 nm using both ns and ps laser pulses, and the experimental data was fitted by a five-band model to extract the singlet and triplet excited-state absorption cross sections. The degree of reverse saturable absorption follows this trend: F-1 = F-2 > F-3 > F-4 > F-5, which is mainly determined by the ratio of the triplet excited-state absorption cross-section to that of the ground-state and the triplet excited-state quantum yield. Comparison of the photophysics of F-1, F-2, and F-3 to those of their corresponding Pt complexes without the fluorenyl substituent discovers that F-1-F-3 exhibit larger molar extinction coefficients for their low-energy charge transfer absorption band, longer triplet excited-state lifetimes, higher emission quantum yields, and increased ratios of the excited-state absorption cross-section to that of the ground-state.
- Shao, Pin,Li, Yunjing,Yi, Jing,Pritchett, Timothy M.,Sun, Wenfang
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scheme or table
p. 4507 - 4517
(2010/07/04)
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- Synthesis and characterization of novel monodisperse starburst oligo(fluoreneethynylene) based on truxene moiety
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A series of novel monodisperse star-shaped oligo(fluoreneethynylene)s, which contain hexahexyltruxene as the central core linked with oligo(fluoreneethynylene) as the arms, are presented. Copyright
- Chen, Qing-Quan,Liu, Feng,Ma, Zhun,Peng, Bo,Wei, Wei,Huang, Wei
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p. 178 - 179
(2008/09/18)
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- Synthesis and energy-transfer properties of hydrogen-bonded oligofluorenes
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A set of fluorene oligomers has been synthesized by stepwise palladium-catalyzed (Suzuki) couplings of fluorene monomers. Ureidopyrimidinones (UPy), functional groups that can dimerize via quadruple hydrogen bonds, were attached to both ends of the oligof
- Dudek, Stephen P.,Pouderoijen, Maarten,Abbel, Robert,Schenning, Albertus P. H. J.,Meijer
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p. 11763 - 11768
(2007/10/03)
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- Dibenzothiophene-S,S-dioxide-fluorene co-oligomers. Stable, highly-efficient blue emitters with improved electron affinity
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Incorporation of dibenzothiophene-S,S-dioxide units into conjugated fluorene oligomers changes the frontier orbital energy levels and presents an effective way to increase the electron affinity of these materials, which are highly fluorescent with bright blue emission in both solution and the solid state. The Royal Society of Chemistry 2005.
- Perepichka, Irene I.,Perepichka, Igor F.,Bryce, Martin R.,Palsson, Lars-Olof
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p. 3397 - 3399
(2007/10/03)
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- A novel amorphous oligo(phenylenevinylene) dimer with a biphenyl linkage center and fluorene end groups for electroluminescent devices
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A new type of oligo(phenylenevinylene) dimer, 2,5,2,5- tetra(9,9-dihexylfluorenyl)biphenyl (TFB), with a biphenyl linkage center and four fluorene end groups, has been synthesized by the Wittig reaction. The full characterization of its structure and optical properties, as well as the performance of its electroluminescent devices are presented. TFB shows strong blue fluorescence both in solution and as a solid film. High-quality films of TFB for light-emitting devices (LEDs) can be fabricated both by vacuum evaporation and the spin-coating technique, which is very special and interesting. Single-layer and multi-layer light-emitting devices using TFB as the active layer all show efficient blue emission.
- He, Feng,Xia, Hong,Tang, Shi,Duan, Yu,Zeng, Ming,Liu, Linlin,Li, Mao,Zhang, Haiquan,Yang, Bing,Ma, Yuguang,Liu, Shiyong,Shen, Jiacong
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p. 2735 - 2740
(2007/10/03)
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- Delocalization of positive and negative charge carriers on oligo- and poly-fluorenes studied by low-temperature matrix isolation technique
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Oligofluorenes with well-defined chain length (n = 1-5) have been synthesized by step-by-step Suzuki coupling reaction as the basis sets of conjugated segments in polyfluorenes. Cation and anion radicals of oligofluorenes (n > 2) showed intense and clear
- Koizumi, Yoshiko,Seki, Shu,Acharya, Anjali,Saeki, Akinori,Tagawa, Seiichi
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p. 1290 - 1291
(2007/10/03)
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- Monodisperse fluorene oligomers exhibiting strong dipolar coupling interactions
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Well-defined fluorene oligomers (n = 1 to 6) were prepared step by step using Suzuki and Yamamoto couplings, while absorption and photoluminescence properties evidenced very large dipolar coupling interactions between fluorene moieties.
- Anemian, Remi,Mulatier, Jean-Christophe,Andraud, Chantal,Stephan, Olivier,Vial, Jean-Claude
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p. 1608 - 1609
(2007/10/03)
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