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1.
Four derivatives of the titled compounds, (8‐hydroxyquinoline)bis(2‐phenylpyridyl)iridium ( IrQ(ppy)2 ), were prepared. Two of them were confirmed by single crystal X‐ray diffraction analyses, in which solvent molecules were found to be incorporated in the crystal lattices. Their emission spectra display separated dual bands in de‐aerated solutions at about 515 and 645 nm upon excitation. These green and red emissions are attributed to the triplet metal‐to‐ligand charge transfer (3MLCT) and triplet ligand centered (3LC) transitions in Ir(ppy)2 and IrQ, respectively. It is suggested that such a multiple emission is feasible by nearly orthogonal orientation between the ppy and quinoline ligands in the mixed‐ligand Ir‐compounds which prohibits energy transfer between the two different ligands. The electroluminescence (EL) of these compounds was examined by the fabrication of light‐emitting diodes (LEDs). Unlike the spectra in solutions, their EL spectra displayed only the red emission band. Devices displaying white light can be obtained by mixing the red emission of IrQ(ppy)2 with a compatible blue emitter (NPB) in separated layers.  相似文献   

2.
We report a significant decrease in turn‐on times of light‐emitting electrochemical cells (LECs) by tethering imidazolium moieties onto a cationic Ir complex. The introduction of two imidazolium groups at the ends of the two alkyl side chains of [Ir(ppy)2(dC6‐daf)]+(PF6)? (ppy=2‐phenylpyridine, dC6‐daf=9,9′‐dihexyl‐4,5‐diazafluorene) gave the complex [Ir(ppy)2(dC6MIM‐daf)]3+[(PF6)?]3 (dC6MIM‐daf=9,9‐bis[6‐(3‐methylimidazolium)hexyl]‐1‐yl‐4,5‐diazafluorene). Both complexes exhibited similar photoluminescent/electrochemical properties and comparable electroluminescent efficiencies. The turn‐on times of the LECs based on the latter complex, however, were much lower than those of devices based on the former. The improvement is ascribed to increased concentrations of mobile counterions ((PF6)?) in the neat films and a consequent increase in neat‐film ionic conductivity. These results demonstrate that the technique is useful for molecular modifications of ionic transition‐metal complexes (ITMCs) to improve the turn‐on times of LECs and to realize single‐component ITMC LECs compatible with simple driving schemes.  相似文献   

3.
A set of novel greenish‐yellow‐, yellow‐, and orange‐light‐emitting polymeric iridium(III) complexes were synthesized with the bridge‐splitting method. The respective dimeric precursor complexes, [Ir(ppy)2‐μ‐Cl]2 (ppy = 2‐phenylpyridine) and [Ir(ppy? CHO)2‐μ‐Cl]2 [ppy? CHO = 4‐(2‐pyridyl)benzaldehyde], were coordinated to 2,2′‐bipyridine carrying poly(ε‐caprolactone) tails. The resulting emissive polymers were characterized with one‐dimensional (1H) and two‐dimensional (1H? 1H correlation spectroscopy) nuclear magnetic resonance and infrared spectroscopy, gel permeation chromatography, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and the successful coordination of the iridium(III) centers to the 2,2′‐bipyridine macroligand was revealed. The thermal behavior was studied with differential scanning calorimetry and correlated with atomic force microscopy. Furthermore, the quantitative coordination was verified by both the photophysical and electrochemical properties of the mononuclear iridium(III) compounds. The photoluminescence spectra showed strong emissions at 535 and 570 nm. The color shifts depended on the substituents of the cyclometallating ligands. Cyclic voltammetry gave oxidation potentials of 1.23 V and 1.46 V. Upon the excitation of the films at 365 nm, yellow light was observed, and this could allow potential applications in light‐emitting devices. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2765–2776, 2005  相似文献   

4.
Electron delocalization of new mixed‐valent (MV) systems with the aid of lateral metal chelation is reported. 2,2′‐Bipyridine (bpy) derivatives with one or two appended di‐p‐anisylamino groups on the 5,5′‐positions and a coordinated [Ru(bpy)2] (bpy=2,2′‐bipyridine), [Re(CO)3Cl], or [Ir(ppy)2] (ppy=2‐phenylpyridine) component were prepared. The single‐crystal molecular structure of the bis‐amine ligand without metal chelation is presented. The electronic properties of these complexes were studied and compared by electrochemical and spectroscopic techniques and DFT/TDDFT calculations. Compounds with two di‐p‐anisylamino groups were oxidized by a chemical or electrochemical method and monitored by near‐infrared (NIR) absorption spectral changes. Marcus–Hush analysis of the resulting intervalence charge‐transfer transitions indicated that electron coupling of these mixed‐valent systems is enhanced by metal chelation and that the iridium complex has the largest coupling. TDDFT calculations were employed to interpret the NIR transitions of these MV systems.  相似文献   

5.
The relationship between density of energetic azole‐based compounds and their molecular structure is investigated through quantitative structure‐property relationship (QSPR) approach. The methodology of this work introduces a new model, which related density of azole‐based energetic compounds to the optimum elemental composition, the degree of unsaturation (DoU) of the compounds, presence of nitroimino group in the structural formula, as well as several non‐additive structural parameters. The presence of nitroimino functional group and also increasing the value of nO/nN in the formula of these compounds can enhance their density. The correlation is derived on the basis of experimental density values of 100 azole‐based energetic compounds with different molecular structure as training set. The determination coefficient of the new correlation is 0.923. Also, it has the root mean square deviation (RMSD) and the average absolute deviation (AAD) of 0.038 and 0.030 g · cm–3, respectively. In addition, the correlation gives good predictions for further 25 azole‐based energetic compounds as test set (Q2EXT = 0.901). The predictive ability of the correlation is checked using a cross validation method (Q2LMO = 0.918). The proposed method can also apply for designing novel azole‐based energetic compounds.  相似文献   

6.
[Bis(imidazolyl)–BH2]+[bis(triazolyl)–BH2]? and [bis(imidazolyl)–BH2]+[tris(triazolyl)–BH]? were synthesized, the cations and anions of which were functionalized with B?H groups and azoles. As B?H groups contribute to the hypergolic activity and azole groups improve the energy output, the resulting ionic liquids exhibited ignition delay times as low as 20 ms and energy outputs as high as 461.1 kJ mol?1. In addition, densities (1.07–1.22 g cm?3) and density‐specific impulse (≈360 s g cm?3) values reached a relatively high level. These ionic liquids show great promise as sustainable rocket fuels.  相似文献   

7.
The synthesis, structure, electrochemistry, and photophysical properties of a series of heteroleptic tris‐ cyclometalated PtIV complexes are reported. The complexes mer‐[Pt(C^N)2(C′^N′)]OTf, with C^N=C‐deprotonated 2‐(2,4‐difluorophenyl)pyridine (dfppy) or 2‐phenylpyridine (ppy), and C′^N′=C‐deprotonated 2‐(2‐thienyl)pyridine (thpy) or 1‐phenylisoquinoline (piq), were obtained by reacting bis‐ cyclometalated precursors [Pt(C^N)2Cl2] with AgOTf (2 equiv) and an excess of the N′^C′H pro‐ligand. The complex mer‐[Pt(dfppy)2(ppy)]OTf was obtained analogously and photoisomerized to its fac counterpart. The new complexes display long‐lived luminescence at room temperature in the blue to orange color range. The emitting states involve electronic transitions almost exclusively localized on the ligand with the lowest π–π* energy gap and have very little metal character. DFT and time‐dependent DFT (TD‐DFT) calculations on mer‐[Pt(ppy)2(C′^N′)]+ (C′^N′=thpy, piq) and mer/fac‐[Pt(ppy)3]+ support this assignment and provide a basis for the understanding of the luminescence of tris‐cyclometalated PtIV complexes. Excited states of LMCT character may become thermally accessible from the emitting state in the mer isomers containing dfppy or ppy as chromophoric ligands, leading to strong nonradiative deactivation. This effect does not operate in the fac isomers or the mer complexes containing thpy or piq, for which nonradiative deactivation originates mainly from vibrational coupling to the ground state.  相似文献   

8.
Novel 2‐(1‐substituted‐1H‐1,2,3‐triazol‐4‐yl)pyridine (pytl) ligands have been prepared by “click chemistry” and used in the preparation of heteroleptic complexes of Ru and Ir with bipyridine (bpy) and phenylpyridine (ppy) ligands, respectively, resulting in [Ru(bpy)2(pytl‐R)]Cl2 and [Ir(ppy)2(pytl‐R)]Cl (R=methyl, adamantane (ada), β‐cyclodextrin (βCD)). The two diastereoisomers of the Ir complex with the appended β‐cyclodextrin, [Ir(ppy)2(pytl‐βCD)]Cl, were separated. The [Ru(bpy)2(pytl‐R)]Cl2 (R=Me, ada or βCD) complexes have lower lifetimes and quantum yields than other polypyridine complexes. In contrast, the cyclometalated Ir complexes display rather long lifetimes and very high emission quantum yields. The emission quantum yield and lifetime (Φ=0.23, τ=1000 ns) of [Ir(ppy)2(pytl‐ada)]Cl are surprisingly enhanced in [Ir(ppy)2(pytl‐βCD)]Cl (Φ=0.54, τ=2800 ns). This behavior is unprecedented for a metal complex and is most likely due to its increased rigidity and protection from water molecules as well as from dioxygen quenching, because of the hydrophobic cavity of the βCD covalently attached to pytl. The emissive excited state is localized on these cyclometalating ligands, as underlined by the shift to the blue (450 nm) upon substitution with two electron‐withdrawing fluorine substituents on the phenyl unit. The significant differences between the quantum yields of the two separate diastereoisomers of [Ir(ppy)2(pytl‐βCD)]Cl (0.49 vs. 0.70) are attributed to different interactions of the chiral cyclodextrin substituent with the Δ and Λ isomers of the metal complex.  相似文献   

9.
Two new charge‐neutral iridium complexes, [Ir(tfm‐ppy)2(N,N′‐diisopropyl‐benzamidinate)] ( 1 ) and [Ir(tfm‐ppy)2(N,N′‐diisopropyl‐4‐diethylamino‐3,5‐dimethyl‐benzamidinate)] ( 2 ) (tfm‐ppy=4‐trifluoromethyl‐2‐phenylpyridine) containing an amidinate ligand and two phenylpyridine ligands were designed and characterised. The photophysical properties, electrochemical behaviours and emission quenching properties of these species were investigated. In concert with the cobalt catalyst [Co(bpy)3]2+, members of this new class of iridium complexes enable the photocatalytic generation of hydrogen from mixed aqueous solutions via an oxidative quenching pathway and display long‐term photostability under constant illumination over 72 h; one of these species achieved a relatively high turnover number of 1880 during this time period. In the case of complex 1 , the three‐component homogeneous photocatalytic system proved to be more efficient than a related system containing a charged complex, [Ir(tfm‐ppy)2(dtb‐bpy)]+ ( 3 , dtb‐bpy=4,4′‐di‐tert‐butyl‐2,2′‐dipyridyl). In combination with a rhodium complex as a water reduction catalyst, the performances of the systems using both complexes were also evaluated, and these systems exhibited a more efficient catalytic propensity for water splitting than did the cobalt‐based systems that have been studied previously.  相似文献   

10.
Highly organic soluble Ir(III) complexes with 9‐(6‐phenyl‐pyridin‐3‐ylmethyl)‐9H‐carbazole were simply synthesized, and the solubility of the new complex was significantly improved when compared with the conventional green‐emitting Ir(ppy)3. Since a carbazole group is tethered through a nonconjugated methylene spacer, the photophysical properties of new complexes are almost identical with those of conventional Ir(ppy)3. The pure complexes were utilized to prepare electrophosphorescent polymer light‐emitting diodes (PLEDs). The device performances were observed to be relatively better or comparable with those of Ir(ppy)3 based poly(N‐vinylcarbazole) systems. The integration of rigid hole‐transporting carbazole and phosphorescent complex provides a new route to design highly efficient solution‐processable complex for electrophosphorescent PLED applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7419–7428, 2008  相似文献   

11.
A series of pyrene‐based bisazolium salts have been obtained starting from 4,5,9,10‐tetrabromo‐2,7‐di‐tert‐butylpyrene. The synthetic procedure to the pyrene‐bisazoliums (PBIs) reveals an unexpected behavior, as a consequence of the presence of the alkyl groups (alkyl=Me, Et, n‐Pr, and n‐Bu) coming from the trisalkoxyformate in the final products, instead of the expected tBu of tAmyl groups from the starting tetra‐aminated pyrenes. All bisazoliums show fluorescence properties, with emissions in the range of 370–420 nm, and quantum yields ranging from 0.29 to 0.41. The PBIs were used as bis‐NHC precursors in the preparation of a series of dirhodium and diiridium complexes, which have been fully characterized. The electrochemical studies on selected dimetallic complexes reveal that the electronic communication between the metals through the polyaromatic linker is negligible.  相似文献   

12.
The preparation and characterization of four narrow band gap pyrene–benzothiadiazole‐based alternating copolymers are presented. An investigation of the impact of attaching different solubilizing groups to the pyrene repeat units on the optical, electrochemical, and thermal properties of the resulting materials was undertaken along with studies on the aggregation of polymer chains in the solid state. Unsurprisingly, polymers which had the smaller 2‐ethylhexyl chains attached to the pyrene units (PPEH‐DTBT and PPEH‐DTffBT) displayed lower molecular weights relative to polymers with larger 2‐hexyldecyl substituents (PPHD‐DTBT and PPHD‐DTffBT). Despite this, the 2‐ethylhexyl substituted polymers displayed narrower optical band gaps relative to their analogous 2‐hexyldecyl substituted polymers. Of all polymers synthesized, PPEH‐DTBT displayed the lowest optical band gap (1.76 eV) in the series. All polymers display degradation temperatures in excess of 300°C. Polymers with smaller alkyl chains on the pyrene units display shallower highest occupied molecular orbital levels, which could be due to increased intramolecular charge transfer between the donor and acceptor units. Preliminary investigations on bulk heterojunction solar cells with a device structure indium tin oxide/poly(3,4‐ethylenedioxythiophene) : polystyrene sulfonate /Polymer : PC70BM/Ca/Al were undertaken. Polymer/PC70BM blend ratios of one third were used in these studies and have indicated that PPEH‐DTBT displayed the highest efficiency with a power conversion efficiency of 1.86%. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

13.
A convenient procedure for the preparation of carbamate derivatives of 5‐oxo‐2,5‐dihydrofuran ( 3 ) was described. The method is based on the Michael type addition of three alkyl carbamates ( 2 ) with 4‐acetyl‐5‐methyl‐2,3‐dihydro‐2,3‐furandione ( 1 ). According to 1H nmr spectra of compounds show tautomeric forms ( 3,4,5 ) in CDC13. In the solid state the synthesized compounds are enol forms ( 3 ). The products were characterized with molecular spectroscopic methods.  相似文献   

14.
Synthesis of the polymer whose end is functionalized by fac‐Ir(ppy)3 (ppy = 2‐phenylpyridyl) was achieved by using (living) anionic polymerization of 1,3‐cyclohexadiene: the reaction of poly(1,3‐cyclohexadienyl)lithium (PCHDLi) with fac‐Ir(ppy)2(vppy) [vppy = 2‐(4‐vinylphenyl)pyridyl] resulted in nucleophilic attack of the carbanion in PCHDLi on the vinyl group of fac‐Ir(ppy)2(vppy) selectively. Complexation of the pyridyl ring protected the α‐carbons of fac‐Ir(ppy)2(vppy) from the reaction of the anionic polymer. The homopolymerization of fac‐Ir(ppy)2(vppy) did not occur, and only one molecule of fac‐Ir(ppy)2(vppy) reacted with the carbanion of PCHDLi and was selectively incorporated into an end of poly(1,3‐cyclohexadiene) (PCHD). Thus, the PCHD with fac‐Ir(ppy)3 end‐group was obtained with a well‐controlled and defined polymer structure and molecular weight. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

15.
Two new pyrene‐cored covalent organic polymers (COPs), CK‐COP‐1 and CK‐COP‐2 , were synthesized via the one‐step polymerization of two thiophene‐based isomers, 1,3,6,8‐tetra(thiophene‐2‐yl) pyrene ( L1 ) and 1,3,6,8‐tetra(thiophene‐3‐yl) pyrene ( L2 ). The resulting pyrene‐cored COPs exhibit rather different surface areas of 54 m2 g?1 and 615 m2g?1 for CK‐COP‐1 and CK‐COP‐2 , respectively. The CO2 uptake capacities of CK‐COP‐1 and CK‐COP‐2 also show different values of 2.85 and 9.73 wt % at 273 K, respectively. Furthermore, CK‐COP‐2 offers not only a larger CO2 adsorption capacity but also a better CO2/CH4 selectivity at 273 K compared with CK‐COP‐1 . CK‐COP‐1 and CK‐COP‐2 also exhibit considerable differences in their photophysical property. The different structure and properties of CK‐COPs could be attributed to the isomer effect of their corresponding thiophene‐based monomers. © 2017 Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2383–2389  相似文献   

16.
Two donor/acceptor (D/A)‐based benzo[1,2‐b:4,5‐b′]dithiophene‐alt‐2,3‐biphenyl quinoxaline copolymers of P 1 and P 2 were synthesized pending different functional groups (thiophene or triphenylamine) in the 4‐positions of phenyl rings. Their thermal, photophysical, electrochemical, and photovoltaic properties, as well as morphology of their blending films were investigated. The poly(4,8‐bis((2‐ethyl‐hexyl)oxy)benzo[1,2‐b:4,5‐b'] dithiophene)‐alt‐(2,3‐bis(4′‐bis(N,N‐bis(4‐(octyloxy) phenylamino)‐ 1,1′‐biphen‐4‐yl)quinoxaline) ( P 2) exhibited better photovoltaic performance than poly(4,8‐bis((2‐ethylhexyl)oxy)benzo[1,2‐b:4,5‐b'] dithiophene)‐alt‐(2,3‐bis(4‐(5‐octylthiophen‐2‐yl)phenyl)quinoxaline) ( P 1) in the bulk‐heterojunction polymer solar cells with a configuration of ITO/PEDOT:PSS/polymers: [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM)/LiF/Al. A power conversion efficiency of 3.43%, an open‐circuit voltage of 0.80 V, and a short‐circuit current of 9.20 mA cm?2 were achieved in the P 2‐based cell under the illumination of AM 1.5, 100 mW cm?2. Importantly, this power conversion efficiency level is 2.29 times higher than that in the P 1‐based cell. Our work indicated that incorporating triphenylamine pendant in the D/A‐based polymers can greatly improved the photovoltaic properties for its resulting polymers.  相似文献   

17.
Several novel materials were investigated as energetic chlorine donors, specifically for the preparation of perchlorate‐free pyrotechnic formulations with low‐smoke output. The novel compounds, 2‐chloromethyl‐2‐methyl‐5,5‐dinitro‐1,3‐dioxane (1‐CDN), 2,2‐bis(chloromethyl)‐5,5‐dinitro‐1,3‐dioxane (13‐CDN), and 2‐(dichloromethyl)‐2‐methyl‐5,5‐dinitro‐1,3‐dioxane (11‐CDN), were formulated with a variety of fuels and oxidizers and their resulting colored flames analyzed for color quality. The preparation and preliminary characterization of these energetic chlorine donors are described.  相似文献   

18.
Carbene Homologues of Germanium, Tin, and Lead with 2‐substituted N ‐Pyrrolyl Ligands A series of germylenes, stannylenes, and plumbylenes could be prepared by reacting the appropriate bis(trimethylsilyl)amino‐substituted carbene homologue E[N(SiMe3)2]2 (E = Ge, Sn, and Pb) with an α‐carbonyl substituted pyrrole derivative under elimination of bis(trimethylsilyl)amine. The isolated compounds have been analysed spectroscopically, and the resulting NMR and IR data were contrasted with parameters obtained from quantumchemical calculations. The good agreement between experimental and theoretical results gives us the opportunity to discuss the vibrations in more detail, particularly those in which the group 14 element is involved. X‐ray crystal structure analyses obtained for five examples show the title compounds essentially to be monomers with primary E–N bonds and, in addition to that, coordinative E ← O contacts.  相似文献   

19.
Convenient procedures for the synthesis of new organophosphorus‐substituted mono‐ and bis(trimethylsilyl)amines with PCH2N moiety are proposed, starting from trimethylsilyl esters of organophosphorus acids, as well as 1,3,5‐trialkylhexahydro‐1,3,5‐triazines and N‐alkoxymethyl bis(trimethylsilyl)amines as aminomethylating reagents. Certain properties of the resulting compounds are presented. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:71–77, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20580  相似文献   

20.
《化学:亚洲杂志》2017,12(20):2703-2710
The preparation and characterization of a new metallogelator based on the IrIII discrete cyclometalated complex [(ppy)2Ir(bpy)](CH3CH2OCH2CO2) are reported, where H(ppy) is 2‐phenylpiridine and bpy is 2,2′‐bipyridine, which is used as an ancillary ligand. The compound is able to self‐assemble in water in a range of concentrations between 3 % and 6 % w/w, creating a luminescent ordered supramolecular gel. The gel and xerogel architectures were investigated through polarized optical microscopy (POM), SEM and TEM microscopies coupled with powder X‐ray diffraction. The gel supramolecular organization is characterized by columnar tetragonal strands, already present at high dilution conditions, of cations surrounded by counteranions. These strands, in turn, are self‐assembled in an oblique columnar cell upon gelification. The xerogel thin films obtained upon complete dehydration maintained the gel supramolecular order and can be used as a precursor for the preparation of nanostructured IrO2 thin films.  相似文献   

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