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1.
Junki Ochi Kazuhiro Yuhara Prof. Kazuo Tanaka Prof. Yoshiki Chujo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(20):e202200155
It is still challenging to realize a dual-emission system, in which two luminescent bands simultaneously appear by photoexcitation, in solid with organic dyes due to the difficulty in regulation of electronic properties in the excited state and concentration quenching. o-Carborane is known to be a versatile platform for constructing solid-state emitters since the sphere boron cluster is favorable for suppressing intermolecular interactions and subsequently concentration quenching. Here, we show solid-state dual-emissive o-carborane derivatives. We prepared 4 types of o-carborane derivatives and found dual-emission behaviors both in solution and solid states. By regulating the rotation at the o-carborane unit with the intramolecular CcageH⋅⋅⋅O interaction, the dual-emission intensity ratios were changed. Finally, it was demonstrated that the overall photoluminescence spectra can be estimated using the binding energy of intramolecular interactions. 相似文献
2.
Recent Progress in the Development of Solid-State Luminescent o-Carboranes with Stimuli Responsivity
Junki Ochi Prof. Dr. Kazuo Tanaka Prof. Dr. Yoshiki Chujo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):9925-9939
o-Carborane, a cluster compound containing boron and adjacent carbon atoms, displays intriguing luminescent properties. Recently, compounds containing o-carborane units were found to show suppressed aggregation-induced quenching and intense solid-state emission; they also show potential for the development of stimuli-responsive luminochromic materials. In this Minireview, we introduce three kinds of fundamental photochemical properties: aggregation-induced emission, twisted intramolecular charge transfer in crystals, and environment-sensitive excimer formation in solids. Based on these properties, several types of luminochromism, such as thermos-, vapo-, and mechanochromism, have been discovered. Based mainly on results from recent studies, we illustrate these mechanisms as well as unique luminescent behaviors of o-carborane derivatives. 相似文献
3.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1988,44(3):273-276
The globular-shaped icosahedral carboranes, o-, m-, and p-C2B10H12, yield high-resolution 11B and 13C MAS solid-state NMR spectra. Chemical shifts and linewidths are comparable to those of solution spectra. Spin—lattice relaxation times indicate the quadrupolar mechanism to be dominant for the B-11 relaxation. Linewidths of spectra recorded at 96 MHz and 64 MHz were similar. At 298 K, the 13C T1 of p-carborane was found to be an order of magnitude smaller than those of the other two isomers. This can be attributed to the higher phase transition temperature of p-carborane indicative of the stronger intermolecular dipolar CH interactions made possible by the para-carbon vertices. Substitution on o-carborane by a methyl group yields spectra of comparable linewidths to those of the parent compound. Substitution by a bulkier phenyl group, however, results in extensive broadening of both 11B and 13C signals of the derivative 1-Ph-o-C2B10H11. 相似文献
4.
E. N. Peters J. H. Kawakami G. T. Kwiatkowski E. Hedaya B. L. Joesten D. W. McNeil D. A. Owens 《Journal of Polymer Science.Polymer Physics》1977,15(4):723-732
D2-m-decacarborane dimethylsiloxane has unusual thermal stability and resistance towards reversion, however, this material exhibits a crystalline phase, Tm at 68°C. To obtain an elastomeric material, this crystallinity is disrupted by replacing 30 to 50% of the m-carborane with p-carborane moieties or by the incorporation of phenyl moieties on the polymer backbone. The latter approach is preferred since improved thermo-oxidative stability accompanies this modification. Correlation of the glass transition temperature and thermo-oxidative stability with the polymer structure are presented. 相似文献
5.
Miao Zhu Qin Zhou He Cheng Prof. Dr. Ye Sha Prof. Dr. Vladimir I. Bregadze Prof. Dr. Hong Yan Prof. Dr. Zhe Sun Prof. Dr. Xiang Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202213470
The combination of carbon-based nanohoops with other functional organic molecular structures should lead to the design of new molecular configurations with interesting properties. Here, necklace-like nanohoops embedded with carborane were synthesized for the first time. The unique deboronization of o-carborane has led to the facile preparation of ionic nanohoop compounds. Nanohoops functionalized by nido-o-carborane show excellent fluorescence emission, with a solution quantum yield of up to 90.0 % in THF and a solid-state quantum efficiency of 87.3 %, which opens an avenue for the applications of the nanohoops in OLEDs and bioimaging. 相似文献
6.
7.
Mikiko Shima Etsuyo Ogawa Seiko Ban Mari Sato 《Journal of Polymer Science.Polymer Physics》1977,15(11):1999-2011
Dilute solution properties of (styrene-p-chlorostyrene) triblock copolymers in various solvents were studied over a wide range of molecular weight and composition. Viscosity and osmotic pressure results indicate that the conformational behavior of the BmAnBm and AmBnAm copolymers (A = styrene; B = p-chlorostyrene; m and n denote the number of units) are similar in nonselective solvents such as toluene and 2-butanone, but different in selective solvents such as carbon tetrachloride and cumene. Short-range and long-range interaction parameters of the block copolymers were determined by applying the Stockmayer–Fixman method to viscosity data and also by application of the equation relating the osmotic virial coefficient and the excluded volume. The results show that the unperturbed dimensions of the block copolymers vary linearly with composition, and long-range interaction parameters in nonselective solvents can be expressed by those of the parent homopolymers, the chemical composition, and values of the interaction parameter βAB between styrene and p-chlorostyrene monomeric units. 相似文献
8.
Evstigneeva R. P. Luzgina V. N. Gorshkov A. Yu. Petrovskii P. V. Ol'shevskaya V. A. Zakharkin L. I. 《Russian Journal of Organic Chemistry》2003,39(1):141-143
New carboranyl-containing porphyrins were synthesized from 2-(2-carboxyvinyl)-5,10,15,20-tetraphenylporphine and 9-hydroxymethyl-m-carborane, 1-hydroxymethyl-o-carborane, and 3-amino-o-carborane. Physical properties of the products were studied. 相似文献
9.
2,5‐Difluorenyl‐Substituted Siloles for the Fabrication of High‐Performance Yellow Organic Light‐Emitting Diodes
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Bin Chen Yibin Jiang Long Chen Han Nie Bairong He Dr. Ping Lu Herman H. Y. Sung Prof. Ian D. Williams Prof. Hoi Sing Kwok Prof. Anjun Qin Prof. Zujin Zhao Prof. Ben Zhong Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(7):1931-1939
2,3,4,5‐Tetraarylsiloles are a class of important luminogenic materials with efficient solid‐state emission and excellent electron‐transport capacity. However, those exhibiting outstanding electroluminescence properties are still rare. In this work, bulky 9,9‐dimethylfluorenyl, 9,9‐diphenylfluorenyl, and 9,9′‐spirobifluorenyl substituents were introduced into the 2,5‐positions of silole rings. The resulting 2,5‐difluorenyl‐substituted siloles are thermally stable and have low‐lying LUMO energy levels. Crystallographic analysis revealed that intramolecular π–π interactions are prone to form between 9,9′‐spirobifluorene units and phenyl rings at the 3,4‐positions of the silole ring. In the solution state, these new siloles show weak blue and green emission bands, arising from the fluorenyl groups and silole rings with a certain extension of π conjugation, respectively. With increasing substituent volume, intramolecular rotation is decreased, and thus the emissions of the present siloles gradually improved and they showed higher fluorescence quantum yields (ΦF=2.5–5.4 %) than 2,3,4,5‐tetraphenylsiloles. They are highly emissive in solid films, with dominant green to yellow emissions and good solid‐state ΦF values (75–88 %). Efficient organic light‐emitting diodes were fabricated by adopting them as host emitters and gave high luminance, current efficiency, and power efficiency of up to 44 100 cd m?2, 18.3 cd A?1, and 15.7 lm W?1, respectively. Notably, a maximum external quantum efficiency of 5.5 % was achieved in an optimized device. 相似文献
10.
Frederic C. Schilling Alan E. Tonelli Ashok L. Cholli 《Journal of Polymer Science.Polymer Physics》1992,30(1):91-96
A comparison of solid-state 13C nuclear magnetic resonance (NMR) spectra of virgin and vacuum γ-irradiated poly (ethylene oxide) (PEO) evidences marked differences. The unirradiated PEO shows a well-resolved amorphous resonance and a weak, broad envelope of crystalline resonances, while the irradiated PEO presents well-resolved resonances for both the crystalline and amorphous carbons. Upon recrystallization from the melt both PEO samples yield solid-state 13C NMR spectra that are closely similar to that of the virgin, unheated sample. Observation of both melt-recrystallized samples at ?60°C yields similar spectra with well-resolved crystalline resonances. Crosslinking is the predominant chemical change occurring during the γ-irradiation of PEO under vacuum and produces a change in the motional character of the crystalline phase. This change is not the result of a reduction in crystallinity as evidenced by differential scanning calorimetry (DSC) observations. The most probable explanation is that the crosslinks are concentrated at the surface of the crystalline lamellae with a resultant change in the low frequency molecular motions of the crystalline chains. This motional change shifts the T1pH such that the crystalline carbon nuclei can now be cross-polarized at room temperature and the resonance linewidth is reduced. Following melting and recrystallization the motional characteristics of the irradiated PEO are nearly identical to those of the unirradiated sample, probably as a result of a redistribution of the crosslinks throughout the amorphous phase during recrystallization. 相似文献
11.
Guosheng Lu Huiyun Yang Hecheng Zhen Cuiyun Li Shanshan Shen 《International Journal of Polymer Analysis and Characterization》2020,25(6):397-408
Abstract Two series of benzoxazines were synthesized from o-, m-, and p-methoxyphenols, two polyetheramines with different molecular weights, and formaldehyde. The glass transition temperatures (T gs) of m-methoxyphenol-based polybenzoxazines are respectively higher than those of o- and p-methoxyphenol-based counterparts. The polybenzoxazines exhibit thermally induced one-way dual-shape memory behavior based on T g, and the o- and p-methoxyphenol-based polybenzoxazines exhibit higher shape memory performance than m-methoxyphenol-based counterparts under motion constraints. 相似文献
12.
Wenting Song Junge Zhi Tianyang Wang Bo Li Shanshan Ni Yanchun Ye Jin‐Liang Wang 《化学:亚洲杂志》2019,14(21):3875-3882
AIE‐active positional isomers, TTE‐o‐PhCHO , TTE‐m‐PhCHO and TTE‐p‐PhCHO , tetrathienylethene ( TTE) derivates with peripherally attached ortho‐/meta‐/para‐formyl phenyl groups, were designed and synthesized. The formyl substitution position can effectively modulate their photophysical properties, mechanochromism and fluorescent response to hydrazine. TTE‐o‐PhCHO and TTE‐m‐PhCHO exhibit remarkable AIE characteristics, and TTE‐p‐PhCHO possesses aggregation‐induced emission enhancement performance. They all exhibit high contrast mechanochromism, and TTE‐m‐PhCHO shows larger red‐shift (164 nm) than TTE‐o‐PhCHO (104 nm) and TTE‐p‐PhCHO (125 nm) due to the more twisted molecular conformation and much looser molecular packing. Moreover, TTE‐o‐PhCHO with a higher contrast color change can be used as ink‐free rewritable paper. In addition, TTE‐p‐PhCHO , as a turn‐on fluorescent probe, can selectively detect hydrazine with significant color changes that are visible by the naked eye . Therefore, the position dependence of groups would be an effective method to modulate the molecular arrangement, as well as develop AIE compounds for mechano‐stimuli responsive materials, ink‐free rewritable papers and chemosensors. 相似文献
13.
Bibhuti Bhusan Jena Soumya Ranjan Jena Biswa Ranjan Swain Chandra Sekhara Mahanta Luna Samanta Barada P. Dash Rashmirekha Satapathy 《应用有机金属化学》2020,34(9):e5754
A series of C3-symmetricaltriazine-cored small dendritic molecules containing three to nine peripheral o-carborane clusters were synthesized through Cu(I)-catalyzedazide–alkyne cycloaddition reactions. The newly synthesized molecules containing multiple o-carborane moieties were characterized using nuclear magnetic resonance and matrix-assisted laser desorption/ionization-time of flight mass spectral analysis. The biological evaluation of these three to nine cage dendrimers was performed using breast cancer cells (Michigan Cancer Foundation 7). All these dendritic compounds showed cytotoxicity toward breast cancer cells, and the toxicity increased as the number of peripheral o-carboranes increased. The 9-cage molecule showed the highest cytotoxicity, and the half maximal inhibitory concentration (IC50) value was found to be 80.67 ng/ml. Its cytotoxicity was significantly higher than the common chemotherapy agent cisplatin. As expected, the boron-richo-carborane-appended molecules showed high thermal stability. The thermal stability increased as the number of peripheral o-carborane moieties increased. 相似文献
14.
Sheth AR Lubach JW Munson EJ Muller FX Grant DJ 《Journal of the American Chemical Society》2005,127(18):6641-6651
Structural and solid-state changes of piroxicam in its crystalline form under mechanical stress were investigated using cryogenic grinding, powder X-ray diffractometry, diffuse-reflectance solid-state ultraviolet-visible spectroscopy, variable-temperature solid-state (13)C nuclear magnetic resonance spectroscopy, and solid-state diffuse-reflectance infrared Fourier transform spectroscopy. Crystalline piroxicam anhydrate exists as colorless single crystals irrespective of the polymorphic form and contains neutral piroxicam molecules. Under mechanical stress, these crystals become yellow amorphous piroxicam, which has a strong propensity to recrystallize to a colorless crystalline phase. The yellow color of amorphous piroxicam is attributed to charged piroxicam molecules. Variable-temperature solid-state (13)C NMR spectroscopy indicates that most of the amorphous piroxicam consists of neutral piroxicam molecules; the charged species comprise only about 8% of the amorphous phase. This ability to quantify the fractions of charged and neutral molecules of piroxicam in the amorphous phase highlights the unique capability of solid-state NMR to quantify mixtures in the absence of standards. Other compounds of piroxicam, which are yellow, are known to contain zwitterionic piroxicam molecules. The present work describes a system in which proton transfer accompanies both solid-state disorder and a change in color induced by mechanical stress, a phenomenon which may be termed mechanochromism of piroxicam. 相似文献
15.
Hongke Wang Hui Lin Prof. Wei Xu Prof. Daoben Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(10):3366-3373
Four novel nonsymmetrical photochromic diarylethene compounds containing dithieno[3,2‐b:2′,3′‐d]thiophene units were designed and synthesized to investigate their photochromic properties. All these molecules adopt a photoactive antiparallel conformation in single crystals, as revealed by X‐ray crystallographic analysis, and exhibit excellent photochromism in solution as well as in the crystalline phase. 相似文献
16.
Dan Wang Gang Wang Ke Liu Jing Li Zhaolong Wang Jing Liu Liping Ding Rong Miao Yu Fang 《中国化学快报》2022,33(5):2532-2536
Based on three rationally designed pyrrole-appended o-carborane derivatives, we present that fluorescence properties of crystalline materials are highly dependent on intermolecular interaction and steric hinderance. Though the three molecules are similar in structure, single crystals of the three compounds showed obvious difference in molecular stacking and fluorescence behavior. Systematic studies indicate that fluorescence quantum yields, thermo-response as well as mechano-response are highly ... 相似文献
17.
Susumu Tajima Seiji Tobita Motohiro Mitani Kazuko Akuzawa Hideo Sawada Masaharu Nakayama 《Journal of mass spectrometry : JMS》1991,26(11):1023-1026
Loss of CO from the molecular ions ([CH3OC6H4COF]+˙) of o-, m- and p-anisoyl fluorides has been investigated by mass-analysed ion kinetic energy (MIKE) spectrometry. This reaction involves fluorine atom migration from the carbonyl group to the benzene ring. In the cases of o- and p-anisoyl fluorides, the fluorine atom migrates via a three-membered transition state to form the molecular ions ([CH3OC6H4F]+˙) of o- and p-fluoroanisoles, respectively. On the other hand, in the case of m-anisoyl fluoride, the fluorine atom migrates from the carbonyl group to the benzene ring via a three- or four-membered transition state. 相似文献
18.
L.I. Zakharkin A.I. Kovredov V.A. Olshevskaya Zh.S. Shaugumbekova 《Journal of organometallic chemistry》1982,226(3):217-222
A convenient new method is proposed for the synthesis of 9-organo-substituted o- and m-carboranes and 2-organo-substituted p-carborane by the substitution of iodine in 9-iodine-o-, 9-iodine-m-, and 2-iodine-p-carboranes by an organic group from an organomagnesium compound in the presence of catalytic amounts of phosphine complexes of palladium. For the first time the halogen in boron halogen carboranes has been substituted by an organic group. 相似文献
19.
Junki Ochi Prof. Dr. Kazuo Tanaka Prof. Dr. Yoshiki Chujo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202214397
Herein, we report the unique solid-state excimer emission of three types of acridine-tethered o-carboranes with variable degrees of methylation at the o-carborane unit. They all showed columnar packing structures based on dimer formation, and two types of π-overlapping motifs were alternately stacked. From the photoluminescence (PL) measurements on the crystalline samples, it was found that three types of luminescence bands can simultaneously appear: monomer emission, excimer emission from the moderately π-stacked intra-dimer unit, and excimer emission from the widely π-stacked inter-dimer unit. Consequently, the PL colors were drastically changed by the steric effect of the methyl groups, with a strong correlation found between the π-overlapping and excimer character. In addition, variable-temperature PL measurements revealed that these PL species should be in thermal equilibrium at room temperature, with the intensity ratios sensitive toward temperature changes. 相似文献
20.
Two copolymers, poly(1,1‐dimethyl‐3,4‐diphenylsilole‐alt‐N‐hexyl‐3,6‐diethynylcarbazole) (PS‐DyCz) and poly(1,1‐dimethyl‐3,4‐diphenylsilole‐alt‐2,7‐diethynyl‐9,9′‐dihexylfluorene) (PS‐DyF), were synthesized by Sonogashira coupling reaction of 2,5‐dibromo‐1,1‐dimethyl‐3,4‐diphenylsilole and N‐hexyl‐3,6‐diethynylcarbazole or 2,7‐diethynyl‐9,9′‐dihexylfluorene, respectively. The chemical structures of the copolymers were characterized by NMR, FT‐IR techniques. Their thermal and photophysical properties were evaluated by TGA, DSC, UV‐Vis and fluorescence spectroscopy, respectively. The weight‐averaged molecular weights (Mw) of PS‐DyCz and PS‐DyF are 1.20×104 and 3.83×104 Da, respectively. The degree of polymerization is 8 and 22 units. These π‐conjugated polymers exhibited lower band‐gap of 2.25 and 2.70 eV due to the presence of silole rings and C?C triple bonds in their backbone, the results were consistent with the density functional (DFT) calculations at the B3LYP/6‐31G* level. 相似文献