共查询到20条相似文献,搜索用时 31 毫秒
1.
Hydrogen‐Bonded Organic Aromatic Frameworks for Ultralong Phosphorescence by Intralayer π–π Interactions
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zaiyong Zhang Xuan Wang Dr. Huili Ma Nan Gan Qi Wu Zhichao Cheng Kun Ling Mingxing Gu Chaoqun Ma Long Gu Prof. Zhongfu An Prof. Wei Huang 《Angewandte Chemie (International ed. in English)》2018,57(15):4005-4009
Ultralong organic phosphorescence (UOP) based on metal‐free porous materials is rarely reported owing to rapid nonradiative transition under ambient conditions. In this study, hydrogen‐bonded organic aromatic frameworks (HOAFs) with different pore sizes were constructed through strong intralayer π–π interactions to enable ultralong phosphorescence in metal‐free porous materials under ambient conditions for the first time. Impressively, yellow UOP with a lifetime of 79.8 ms observed for PhTCz‐1 lasted for several seconds upon ceasing the excitation. For PhTCz‐2 and PhTCz‐3, on account of oxygen‐dependent phosphorescence quenching, UOP could only be visualized in N2, thus demonstrating the potential of phosphorescent porous materials for oxygen sensing. This result not only outlines a principle for the design of new HOFs with high thermal stability, but also expands the scope of metal‐free luminescent materials with the property of UOP. 相似文献
2.
Yunxiang Lei Wenbo Dai Jianxin Guan Shuai Guo Fei Ren Yudai Zhou Jianbing Shi Bin Tong Zhengxu Cai Junrong Zheng Yuping Dong 《Angewandte Chemie (International ed. in English)》2020,59(37):16054-16060
Organic materials with long‐lived, color‐tunable phosphorescence are potentially useful for optical recording, anti‐counterfeiting, and bioimaging. Herein, we develop a series of novel host–guest organic phosphors allowing dynamic color tuning from the cyan (502 nm) to orange red (608 nm). Guest materials are employed to tune the phosphorescent color, while the host materials interact with the guest to activate the phosphorescence emission. These organic phosphors have an ultra‐long lifetime of 0.7 s and a maximum phosphorescence efficiency of 18.2 %. Although color‐tunable inks have already been developed using visible dyes, solution‐processed security inks that are temperature dependent and display time‐resolved printed images are unprecedented. This strategy can provide a crucial step towards the next‐generation of security technologies for information handling. 相似文献
3.
Wei Xu Yaguo Yu Xiaonan Ji Huarui Zhao Jinming Chen Yanyan Fu Huimin Cao Qingguo He Jiangong Cheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16164-16168
The stability of pure organic room‐temperature phosphorescent (RTP) materials in air has been a research hotspot in recent years. Without crystallization or encapsulation, a new strategy was proposed to obtain self‐stabilized organic RTP materials, based on a complete ionization of a photo‐induced charge separation system. The ionization of aromatic phenol 4‐carbazolyl salicylaldehyde (CSA) formed a stable H‐bonding anion–cation radical structure and led to the completely amorphous CSA‐I film. Phosphorescent lifetimes as long as 0.14 s at room temperature and with direct exposure to air were observed. The emission intensity was also increased by 21.5‐fold. Such an amorphous RTP material reconciled the contradiction between phosphorescence stability and vapor permeability and has been successfully utilized for peroxide vapor detection. 相似文献
4.
Janna Nibbs Sergei A. Vinogradov Jane M. Vanderkool Bogumil Zelent 《Photochemistry and photobiology》2004,80(1):36-40
The heme in horseradish peroxidase (HRP) was replaced by phosphorescent Pt‐mesoporphyrin IX (PtMP), which acted as a phosphorescent marker of oxygen quenching and allowed comparison with another probe, Pd‐mesoporphyrin IX (Khajehpour et al. (2003) Proteins 53, 656–666). Benzohydroxamic acid (BHA), a competitive inhibitor of the enzyme, was also used to monitor its effects on phosphorescence quenching. With the addition of BHA, in the presence of oxygen, the phosphorescence intensity of the protein increased. In contrast, the addition of BHA, in the absence of oxygen, reduced the phosphorescence intensity of the protein. Kd= 18 μM when BHA binds to PtMP‐HRP. The effect of BHA can be explained by two factors: ( 1 ) BHA reduces the accessibility of O2 to the protein interior and ( 2 ) BHA itself quenches the phosphorescence. Consistent with this, the oxygen quenching of the phosphorescence of PtMP‐HRP gave a quenching constant of kq= 234 mm Hg?1 s?1 in the absence of BHA and kq= 28.7 mm Hg?1 s?1 in the presence of BHA. The quenching rate of BHA is 4000 s?1. The relative quantum yield of the phosphorescence of the Pt derivative is about six times that of the Pd derivative, whereas the phosphorescence lifetime is approximately eight times shorter. The high quantum yield and suitable lifetime make Pt‐porphyrins appropriate as sensors of O2 diffusion and flexibility in heme proteins. 相似文献
5.
Materials having long afterglow are highly sought after for various applications such as light‐emitting diodes, security signs and bioimaging. Herein, we report a simple, low‐cost synthesis of a purely organic room‐temperature phosphorescent nanomaterial with a pebble‐like structure by heating urea, a biocompatible and easily available precursor, at 200 °C with a high phosphorescence lifetime of 1.0365 s and a visible afterglow for up to 10 s. This urea derived phosphorescent nanocomposite (UPNC) can be mixed with commercially available acrylic paint base and common gum, which can be readily used as a phosphorescent pigment. 相似文献
6.
Zhu Wu Jrn Nitsch Julia Schuster Alexandra Friedrich Katharina Edkins Marcel Loebnitz Fabian Dinkelbach Vladimir Stepanenko Frank Würthner Christel M. Marian Lei Ji Todd B. Marder 《Angewandte Chemie (International ed. in English)》2020,59(39):17137-17144
Achieving highly efficient phosphorescence in purely organic luminophors at room temperature remains a major challenge due to slow intersystem crossing (ISC) rates in combination with effective non‐radiative processes in those systems. Most room temperature phosphorescent (RTP) organic materials have O‐ or N‐lone pairs leading to low lying (n, π*) and (π, π*) excited states which accelerate kisc through El‐Sayed's rule. Herein, we report the first persistent RTP with lifetimes up to 0.5 s from simple triarylboranes which have no lone pairs. RTP is only observed in the crystalline state and in highly doped PMMA films which are indicative of aggregation induced emission (AIE). Detailed crystal structure analysis suggested that intermolecular interactions are important for efficient RTP. Furthermore, photophysical studies of the isolated molecules in a frozen glass, in combination with DFT/MRCI calculations, show that (σ, B p)→(π, B p) transitions accelerate the ISC process. This work provides a new approach for the design of RTP materials without (n, π*) transitions. 相似文献
7.
Zhi‐Yuan Zhang Yong Chen Yu Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(18):6089-6093
Efficient emission of purely organic room‐temperature phosphorescence (RTP) is of great significant for potential application in optoelectronics and photobiology. Herein, we report an uncommon phosphorescent effect of organic single molecule enhanced by resulting supramolecular assembly of host–guest complexation. The chromophore bromophenyl‐methyl‐pyridinium (PY) with different counterions as guests display various phosphorescence quantum yields from 0.4 % to 24.1 %. Single crystal X‐ray diffraction results indicate that the chromophore with iodide counterion (PYI) exhibits the highest efficiency maybe due to the halogen‐bond interactions. Significantly, the nanosupramolecular assembly of PY chloride complexation with the cucurbit[6]uril gives a greatly enhanced phosphorescent quantum yield up to 81.2 % in ambient. Such great enhancement is because of the strict encapsulation of cucurbit[6]uril, which prevents the nonradiative relaxation and promotes intersystem crossing (ISC). This supramolecular assembly concept with counterions effect provides a novel approach for the improvement of RTP. 相似文献
8.
Dr. Zhi-Yuan Zhang Wen-Wen Xu Wen-Shi Xu Jie Niu Xiao-Han Sun Prof. Dr. Yu Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18907-18913
An enhancement strategy is realized for ultralong bright room-temperature phosphorescence (RTP), involving polymerization between phosphor monomers and acrylamide and host–guest complexation interaction between phosphors and cucurbit[6,7,8]urils (CB[6,7,8]). The non-phosphorescent monomers exhibit 2.46 s ultralong lifetime after copolymerizing with acrylamide. The improvement is due to the rich hydrogen bond and carbonyl within the polymers which promote intersystem crossing, suppress nonradiative relaxation and shield quenchers effectively. By tuning the ratio of chromophores, a series of phosphorescent copolymers with different lifetimes and quantum yields are prepared. The complexation of macrocyclic hosts CB[6,7,8] promote the RTP of polymers by blocking aggregation-caused quenching, and offsetting the losses of aforementioned interaction provided by polymer. Multiple lifetime-encoding for digit and character encryption are achieved by utilizing the difference of their lifetimes. 相似文献
9.
Azusa Kikuchi Nozomi Oguchi‐Fujiyama Kazuyuki Miyazawa Mikio Yagi 《Photochemistry and photobiology》2014,90(3):511-516
The phosphorescence decay of a UV‐A absorber, 4‐tert‐butyl‐4′‐methoxydibenzolymethane (BMDBM) has been observed following a 355 nm laser excitation in the absence and presence of UV‐B absorbers, 2‐ethylhexyl 4‐methoxycinnamate (octyl methoxycinnamate, OMC) and octocrylene (OCR) in ethanol at 77 K. The lifetime of the lowest excited triplet (T1) state of BMDBM is significantly reduced in the presence of OMC and OCR. The observed quenching of BMDBM triplet by OMC and OCR suggests that the intermolecular triplet–triplet energy transfer occurs from BMDBM to OMC and OCR. The T1 state of OCR is nonphosphorescent or very weakly phosphorescent. However, we have shown that the energy level of the T1 state of OCR is lower than that of the enol form of BMDBM. Our methodology of energy‐donor phosphorescence decay measurements can be applied to the study of the triplet–triplet energy transfer between UV absorbers even if the energy acceptor is nonphosphorescent. In addition, the delayed fluorescence of BMDBM due to triplet–triplet annihilation was observed in the BMDBM–OMC and BMDBM–OCR mixtures in ethanol at 77 K. Delayed fluorescence is one of the deactivation processes of the excited states of BMDBM under our experimental conditions. 相似文献
10.
Zhichao Cheng Dr. Huifang Shi Dr. Huili Ma Lifang Bian Qi Wu Long Gu Suzhi Cai Xuan Wang Prof. Wei‐wei Xiong Prof. Zhongfu An Prof. Wei Huang 《Angewandte Chemie (International ed. in English)》2018,57(3):678-682
A new type of materials, organic salts in the crystal state, have ultralong organic phosphorescence (UOP) under ambient conditions. The change of cations (NH4+, Na+, or K+) in these phosphors gives access to tunable UOP colors ranging from sky blue to yellow green, along with ultralong emission lifetimes of over 504 ms. Single‐crystal analysis reveals that unique ionic bonding can promote an ordered arrangement of organic salts in crystal state, which then can facilitate molecular aggregation for UOP generation. Additionally, reversible ultralong phosphorescence can be realized through the alternative employment of fuming gases (ammonia and hydrogen chloride), demonstrating its potential as a candidate for visual ammonic or hydrogen chloride gas sensing. The results provide an environmental responsible and practicable synthetic approach to expanding the scope of ultralong organic phosphorescent materials as well as their applications. 相似文献
11.
Goudappagouda Ananthakrishnan Manthanath Vivek Chandrakant Wakchaure Kayaramkodath Chandran Ranjeesh Tamal Das Kumar Vanka Takashi Nakanishi Sukumaran Santhosh Babu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2306-2310
Organic phosphors have been widely explored with an understanding that crystalline molecular ordering is a requisite for enhanced intersystem crossing. In this context, we explored the room‐temperature phosphorescence features of a solvent‐free organic liquid phosphor in air. While alkyl chain substitution varied the physical states of the bromonaphthalimides, the phosphorescence remained unaltered for the solvent‐free liquid in air. As the first report, a solvent‐free liquid of a long swallow‐tailed bromonaphthalimide exhibits room‐temperature phosphorescence in air. Doping of the phosphor with carbonyl guests resulted in enhanced phosphorescence, and hence a large‐area paintable phosphorescent liquid composite with improved lifetime and quantum yield was developed. 相似文献
12.
We report a study of excited-state lifetimes of the phosphorescent organometallic complex Ir(ppy)3 on ensemble and a single-molecule level. With decreasing concentration, an increasingly intense fast component of 3 ns lifetime appears next to the 1.1 mus phosphorescence. Experimental evidence suggests that strong two-photon absorption followed by fluorescence is responsible for the fast lifetime component. 相似文献
13.
He Wang Huifang Shi Wenpeng Ye Xiaokang Yao Qian Wang Chaomin Dong Wenyong Jia Huili Ma Suzhi Cai Kaiwei Huang Lishun Fu Yanyun Zhang Jiahuan Zhi Long Gu Yanli Zhao Zhongfu An Wei Huang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):18952-18958
Amorphous purely organic phosphorescence materials with long‐lived and color‐tunable emission are rare. Herein, we report a concise chemical ionization strategy to endow conventional poly(4‐vinylpyridine) (PVP) derivatives with ultralong organic phosphorescence (UOP) under ambient conditions. After the ionization of 1,4‐butanesultone, the resulting PVP‐S phosphor showed a UOP lifetime of 578.36 ms, which is 525 times longer than that of PVP polymer itself. Remarkably, multicolor UOP emission ranging from blue to red was observed with variation of the excitation wavelength, which has rarely been reported for organic luminescent materials. This finding not only provides a guideline for developing amorphous polymers with UOP properties, but also extends the scope of room‐temperature phosphorescence (RTP) materials for practical applications in photoelectric fields. 相似文献
14.
Peifa Wei Xuepeng Zhang Junkai Liu Guo‐Gang Shan Haoke Zhang Ji Qi Weijun Zhao Herman H.‐Y. Sung Ian D. Williams Jacky W. Y. Lam Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2020,59(24):9293-9298
Supramolecular macrocyclic hosts have long been used in smart materials. However, their triplet emission and regulation at crystal level is rarely studied. Herein, ultralong and universal room‐temperature phosphorescence (RTP) is reported for traditional crown ethers. A supramolecular strategy involving chain length adjustment and morphological locking through complexation with K+ was explored as a general method to tune the phosphorescence lifetime in the solid state. A maximum 10‐fold increase of lifetime after complex formation accompanied with by invisible to visible phosphorescence was achieved. A deep encryption based on this activated RTP strategy was also facilely fabricated. This work thus opens a new world for supramolecular macrocycles and their intrinsic guest responsiveness offers a new avenue for versatile smart luminescent materials. 相似文献
15.
In this study, green phosphorescent Pt(II) complexes with N,N‐diphenyl‐6‐(1H‐pyrazol‐1‐yl)pyridin‐2‐amine (Ndpp) coordinated ligands, [Pt (Ndpp)Cl] 2a , [Pt (Ndpp)Pb, Pb = (prop‐1‐ynyl)benzene] 2b , and [Pt (Ndpp)CN] 2a? CN were theoretically investigated by means of density functional theory and time‐dependent density functional theory calculations to reveal their marked distinct phosphorescence quantum yields. These complexes exhibit evident absorption bands in the 200–450 nm region but emit strong green light with marked differences of phosphorescence quantum yields. Compared with the complex 2a , the complex 2b possesses large oscillator strengths of absorption spectra, strong spin‐orbit coupling, and transition electric dipole moment, as well as small singlet‐triplet splitting energies, which conduces to enhancing its radiative decay. To illustrate the nonradiative decay process, the transition state (TS) between the triplet metal‐centered (3MC) state and the excited state (T1) was optimized. The 3MC state is found to be the minimum energy crossing point (MECP) between the T1 state and the S0 state. Compared with the complex 2a , the complex 2b possesses a much larger energy barrier to the MECP state from the T1 state, so it is strongly emissive in the green region. Besides, the introduction of ? CN substitutions on 2a is useful for enhancing the energy barrier to the thermal deactivation pathway of 3MLCT → TS → MECP. These results demonstrate that the modification of metal–ligand conjugation is an effective way to develop high‐performance phosphorescent materials. 相似文献
16.
《Helvetica chimica acta》2017,100(4)
Heavy metal complexes exhibit high phosphorescent efficiency and have been used extensively for electrophosphorescent emitters in the past 16 years. In 2006, we initially reported the use of the popular ligand, 8‐hydroxyquinoline (Q) to coordinate with the heavy metal ions and obtained the red‐infrared phosphorescent emission. In this paper, 8‐hydroxyquinoline has been modified at the 5‐position by electron‐donating and attracting groups and platinum complexes based on 2‐phenylpyridine and 8‐hydroxyquinoline derivatives were synthesized. The electron‐withdrawing group CF 3 and NO 2 lowers the HOMO level of the Q ligand and results in a N^O centered enhanced red‐infrared phosphorescence emission. The complex with CF 3 modification exhibits the highest phosphorescence quantum yield in solid state with a life time of 1.17 μs. 相似文献
17.
The UV absorption, phosphorescence and phosphorescence‐excitation spectra of benzophenone (BP) derivatives used as organic UV absorbers have been observed in rigid solutions at 77 K. The triplet–triplet absorption spectra have been observed in acetonitrile at room temperature. The BP derivatives studied are 2,2′,4,4′‐tetrahydroxybenzophenone (BP‐2), 2‐hydroxy‐4‐methoxybenzophenone (BP‐3), 2,2′‐dihydroxy‐4,4′‐dimethoxybenzophenone (BP‐6), 5‐chloro‐2‐hydroxybenzophenone (BP‐7) and 2‐hydroxy‐4‐n‐octyloxybenzophenone (BP‐12). The energy levels and lifetimes of the lowest excited triplet (T1) states of these BP derivatives were determined from the first peak of phosphorescence. The time‐resolved near‐IR emission spectrum of singlet oxygen generated by photosensitization with BP‐7 was observed in acetonitrile at room temperature. BP‐2, BP‐3, BP‐6 and BP‐12 show photoinduced phosphorescence enhancement in ethanol at 77 K. The possible mechanism of the observed phosphorescence enhancement is discussed. The T1 states of 2‐hydroxy‐5‐methylbenzophenone, 4‐methoxybenzophenone and 2,4′‐dimethoxybenzophenone have been studied for comparison. 相似文献
18.
Xuan Wang Nan Gan Mingxing Gu Kun Ling Chaoqun Ma Huili Ma Wei Yao Yujian Zhang Huifang Shi Zhongfu An Wei Huang 《中国化学快报》2019,30(11):1935-1938
Ultralong organic phosphorescent materials have invoked considerable attention for their great potential in sensing, data encryption, information anti-counterfeiting and so forth. However, effective ways to achieve highly efficient ultralong organic phosphorescence (UOP) in metal-free organic materials remain a great challenge. Herein, we designed three isomers based on asymmetric triazines with various bromine substituted positions. Impressively, phosphorescence efficiency of p-BrAT in solid state can reach up to 9.7% with a long lifetime of 386 ms, which was one of the highest efficient UOP materials reported so far. Theoretical calculations further demonstrated that para-substitution exhibited the most effective radiative transition for triplet excitons. These results will provide an effective approach to achieving highly efficient UOP materials. 相似文献
19.
Yan Tang Hui‐Ran Yang Hui‐Bin Sun Prof. Shu‐Juan Liu Jing‐Xia Wang Prof. Qiang Zhao Dr. Xiang‐Mei Liu Dr. Wen‐Juan Xu Prof. Sheng‐Biao Li Prof. Wei Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(4):1311-1319
Biothiols, such as cysteine (Cys) and homocysteine (Hcy), play very crucial roles in biological systems. Abnormal levels of these biothiols are often associated with many types of diseases. Therefore, the detection of Cys (or Hcy) is of great importance. In this work, we have synthesized an excellent “OFF‐ON” phosphorescent chemodosimeter 1 for sensing Cys and Hcy with high selectivity and naked‐eye detection based on an IrIII complex containing a 2,4‐dinitrobenzenesulfonyl (DNBS) group within its ligand. The “OFF‐ON” phosphorescent response can be assigned to the electron‐transfer process from IrIII center and C^N ligands to the DNBS group as the strong electron‐acceptor, which can quench the phosphorescence of probe 1 completely. The DNBS group can be cleaved by thiols of Cys or Hcy, and both the 3M LCT and 3LC states are responsible for the excited‐state properties of the reaction product of probe 1 and Cys (or Hcy). Thus, the phosphorescence is switched on. Based on these results, a general principle for designing “OFF‐ON” phosphorescent chemodosimeters based on heavy‐metal complexes has been provided. Importantly, utilizing the long emission‐lifetime of phosphorescence signal, the time‐resolved luminescent assay of 1 in sensing Cys was realized successfully, which can eliminate the interference from the short‐lived background fluorescence and improve the signal‐to‐noise ratio. As far as we know, this is the first report about the time‐resolved luminescent detection of biothiols. Finally, probe 1 has been used successfully for bioimaging the changes of Cys/Hcy concentration in living cells. 相似文献
20.
Qi Cao Jing Wang Zhao‐Shuo Tian Zai‐Feng Xie Fu‐Quan Bai 《Journal of computational chemistry》2012,33(10):1038-1046
In the search for efficiently phosphorescent materials, this article presents a rational design and theoretical comparative study of some photophysical properties in the (fpmb)xIr(bptz)3‐x (x = 1–2), which involve the usage of two 2‐pyridyl triazolate ( bptz ) chromophores and a strong‐field ligand fpmb ( fpmb = 1‐(4‐difluorobenzyl)‐3‐methylbenzimidazolium). The first principle theoretical analysis under the framework of the time‐dependent density functional theory approach is implemented in this article to investigate the electronic structures, absorption and phosphorescence spectra. It is intriguing to note that 1 and 2 exhibit theirs blue phosphorescent emissions with maxima at 504 and 516 nm, respectively. Furthermore, to obtain the mechanism of low phosphorescence yield in 1 and estimate the radiative rate constant kr for 2 , we approximately measure the radiative rate constant kr, the spin‐orbital coupling (SOC) value, ΔE (S ? T), and the square of the SOC matrix element (<ΨS1.HSO.ΨT1>2) for 1 and 2 . Finally, we tentatively come to conclusion that the switch of the cyclometalated ligand from the main to ancillary chelate seems to lower the splitting ΔE (S ? T) in the current system. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012 相似文献