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Quantum yield

Feng Chen, Liucan Wang, Yuxin Xing, Jixi Zhang
The photoluminescence stability of lanthanide complex in aqueous media is a prerequisite for diagnostics probes. The combination of building blocks working in concert to facilitate host-guest structures is now considered state of the art in surpassing this roadblock, yet there still remains a tremendous challenge. Here, a stable, highly-luminescent system was developed through trapping anionic complexes sensitized by tridentate pyridine-tetrazolate (pytz) ligands within the rigid framework of ZIF-8 (zeolitic imidazolate framework-8) particles (∼60 nm in size)...
May 16, 2018: Journal of Colloid and Interface Science
E M Kirilova, A I Puckins, E Romanovska, M Fleisher, S V Belyakov
Several new substituted amidine derivatives of benzanthrone were synthesized by condensation reaction from 2-bromo-3-aminobenzo[de]anthracen-7-one and appropriate aromatic or aliphatic amides. The novel benzanthrone derivatives were characterized by TLC analysis, NMR, IR, MS, UV/Vis, and fluorescence spectroscopy. The obtained derivatives have yellow or orange fluorescence in organic solvents. The solvent effect on photophysical behaviors of these dyes was investigated, and the results showed that the introduction of a bromine atom causes a blue-shift of the absorption and emission bands and decrease in the fluorescent quantum yield in comparison with unbromated analogues...
May 9, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yuanyuan Li, Xue Hu, Xiaodan Zhang, Haiyan Cao, Yuming Huang
Contrary to organic solvent-induced aggregation of Au nanoclusters (AuNCs), herein, we reported aggregation induced emission enhancement (AIEE) of AuNCs in an aqueous media through confinement of AuNCs by in situ formed Zn-MOF for detecting Zn2+ . Glutathione capped AuNCs (GSH-AuNCs) was synthesized through reduction of Au3+ by glutathione. Zn2+ could significantly enhance the fluorescence of GSH-AuNCs upon addition of 2-methylimidazole, which was attributed to the formation of Zn-MOF. XRD and TEM were used to characterize the in situ formed Zn-MOF...
September 18, 2018: Analytica Chimica Acta
Lixia Guo, Xiaoju Wang, Liheng Feng
A blue emitter, 3,3'-(2,2'-dimethoxy-[1,1'-binaphthalene]-6,6'-diyl)bis(9-benzyl-9H-carbazole), was synthesized by Suzuki coupling reaction. The photophysical properties of the emitter in solution were firstly investigated by UV-Vis absorption and fluorescence emission techniques. The results indicate that the emitter has excellent optical and electron transfer properties. The maximum absorption and emission peaks of the emitter are 302 nm and 406 nm with 67.4% fluorescence quantum yield in chloroform, respectively...
May 10, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Julie A Peterson, Chamari Wijesooriya, Elizabeth J Gehrmann, Kaitlyn M Mahoney, Pratik P Goswami, Toshia R Albright, Aleem Syed, Andrew S Dutton, Emily A Smith, Arthur H Winter
Photocages are light-sensitive chemical protecting groups that provide external control over when, where, and how much of a biological substrate is activated in cells using targeted light irradiation. Regrettably, most popular photocages (e.g. o-nitrobenzyl groups) absorb cell-damaging ultraviolet wavelengths. A challenge with achieving longer wavelength bond-breaking photochemistry is that long-wavelength-absorbing chromophores have shorter excited state lifetimes and diminished excited state energies. However, here we report the synthesis of a family of BODIPY-derived photocages with tunable absorptions across the visible/near-IR that release chemical cargo under irradiation...
May 18, 2018: Journal of the American Chemical Society
Yui Masumoto, Naoyuki Toriumi, Atsuya Muranaka, Eiichi Kayahara, Shigeru Yamago, Masanobu Uchiyama
Cycloparaphenylenes (CPPs) are hoop-shaped conjugated hydrocarbons corresponding to partial structures of fullerenes or armchair carbon nanotubes. Here, we examined the fluorescence properties of a series of [n]cycloparaphenylene dications ([n]CPP2+, n = 5-9), which have unique in-plane aromaticity. The fluorescence peak positions of the [n]CPP2+s shifted to the longer-wavelength region with increasing ring size, reaching the near-infrared region for those with n > 5. The fluorescence quantum yield of [6]CPP2+ was the highest among the [n]CPP2+s examined in this study, and the value was of the same order as that of carbon nanotubes...
May 18, 2018: Journal of Physical Chemistry. A
Xiaofei Shi, Zhihao Wang, Toshiaki Takei, Xuejiao Wang, Qi Zhu, Xiaodong Li, Byung-Nam Kim, Xudong Sun, Ji-Guang Li
Hydrothermal reaction at 200 °C was systematically undertaken in wide ranges of solution pH (4-13) and W/La molar ratio ( R = 0.5-2), without using any organic additive, to investigate the effect of hydrothermal parameter on product property and the underlying mechanism. Combined analysis by X-ray diffraction (XRD), inductively coupled plasma (ICP) spectroscopy, elemental mapping, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that either a decreasing pH or increasing R value yielded a product richer in W and, conversely, richer in La...
May 18, 2018: Inorganic Chemistry
Lin Wang, Baiquan Liu, Xin Zhao, Hilmi Volkan Demir, Haoshuang Gu, Handong Sun
All-inorganic cesium halide perovskite nanocrystals have attracted booming interests in optoelectronic applications for the sake of the readily adjustable bandgaps, high photoluminescence quantum yield, pure color emission and affordable cost. However, due to the ineluctable utilization of organic surfactants during the synthesis, the structural and optical properties of CsPbBr3 nanocrystals degrade upon transforming from colloidal solutions to solid thin films, which plagues the device operation. Here, we develop a novel solvent-assisted surface engineering strategy, producing high quality CsPbBr3 thin films for device applications...
May 18, 2018: ACS Applied Materials & Interfaces
Zhanqiang Xu, Kazuaki Oniwa, Hiromasa Kikuchi, Ming Bao, Yoshinori Yamamoto, Tienan Jin, Masahiro Terada
Star-shaped π-extended molecules comprising discotic aromatic cores and peripheral π-conjugated arms have attracted significant attention as diverse optoelectronic materials in terms of their large π-surface, tunable self-assembly, enhanced charge transport and fluorescence, and liquid crystallinity. Although many efforts have been made in construction of various aromatic discotic cores, a new class of C3-symmetric star-shaped discotic π-molecules consisting of electron-deficient benzotristhiazole and benzotrisoxazole cores remains unexplored owing to the unachievable synthetic approaches, which are expected to exhibit distinct optoelectronic properties...
May 18, 2018: Chemistry: a European Journal
Mateusz Dyda, Iwona Wąsek, Mirosław Tyrka, Maria Wędzony, Magdalena Szechyńska-Hebda
Microdochium nivale is a fungal pathogen that causes yield losses of cereals during winter. Cold hardening under light conditions induces genotype-dependent resistance of a plant to infection. We aim to show how photosystem II (PSII) regulation contributes to plant resistance. Using mapping population of triticale doubled haploid lines, three M. nivale strains and different infection assays, we demonstrate that plants that maintain a higher maximum quantum efficiency of PSII show less leaf damage upon infection...
May 17, 2018: Physiologia Plantarum
Rong Zhou, Lingpeng Kong, Zhen Wu, Eva Rosenqvist, Yinlei Wang, Liping Zhao, Tongmin Zhao, Carl-Otto Ottosen
In nature, crops encounter a combination of abiotic stresses that severely limit yield. Our aim was to dynamically expose the changes of tomatoes' physiological parameters to drought, heat and their combination and thereby clarify the relationship between the responses to single and combined stress. We studied the effect of single and combined drought and heat stresses on the shoot and root of two tomato cultivars (Sufen No.14 as CV1; Jinlingmeiyu as CV2). After being exposed to combined stress for six days, the dry weight of shoot and root significantly decreased...
May 17, 2018: Physiologia Plantarum
Fang Wang, Christopher A DeRosa, Margaret L Daly, Daniel Song, Cassandra L Fraser
Difluoroboron β-diketonate (BF2 bdk) compounds show environment-sensitive optical properties in solution, aggregation-induced emission (AIE) and multi-stimuli responsive fluorescence switching in the solid state. Here, a series of 4-azepane-substituted β-diketone (bdk) ligands ( L-H , L-OMe , L-Br ) and their corresponding difluoroboron dyes ( D-H , D-OMe , D-Br ) were synthesized, and various responsive fluorescence properties of the compounds were studied, including solvatochromism, viscochromism, AIE, mechanochromic luminescence (ML) and halochromism...
September 1, 2017: Materials Chemistry Frontiers
Vítor Gabriel Ambrosini, Daniel José Rosa, George Wellington Bastos de Melo, Jovani Zalamena, Cesar Cella, Daniela Guimarães Simão, Leandro Souza da Silva, Henrique Pessoa Dos Santos, Moreno Toselli, Tadeu Luis Tiecher, Gustavo Brunetto
High copper (Cu) soil contents, due to the continuous vineyard application of Cu fungicides throughout the years, may impair the growth of the shoot and modify the structure of the root system. The current study aimed to investigate the threshold levels of available Cu in the soil causing toxicity effects in young grapevine plants of 'Red Niagara' cultivated in clay soils. Grapevine plantlets were cultivated in pots containing vineyard devoted soils with increasing contents of available Cu (25, 80, 100 and 165 mg kg-1 ), for 53 days...
May 8, 2018: Plant Physiology and Biochemistry: PPB
Changjian Li, Yueqi Wang, Xiaojie Zhang, Xueling Guo, Xiaoxuan Kang, Libo Du, Yang Liu
Carbon dots have attracted considerable attention in the field of biosensors and bioimaging because of their excellent optical performance and low toxicity. However, the cellular uptake of the reported carbon dots generally has a low efficiency, which limits their practical applications. In this study, we reported a novel red fluorescent sulfur and nitrogen co-doped carbon dots with small molecular phenylboronic acid tags (i.e. S, N-CDs-PBA). The S, N-CDs-PBA can be taken up rapidly by PC12 cells in twenty minutes and showed high sensitivity for the detection of Fe3+ ions...
May 9, 2018: Journal of Colloid and Interface Science
Indranil Roy, Sharan Bobbala, Jiawang Zhou, Minh T Nguyen, Siva Krishna Mohan Nalluri, Yilei Wu, Daniel Ferris, Evan Alexander Scott, Michael R Wasielewski, J Fraser Stoddart
The ideal fluorescent probe for live-cell imaging is bright, non-cytotoxic and can be delivered easily into the living cells in an efficient manner. The design of synthetic fluorophores, having all three of these properties, however, has proved to be challenging. Here, we introduce a simple, yet effective, strategy based on well-established chemistry for designing a new class of fluorescent probes for live-cell imaging. A box-like hybrid cyclophane, namely ExTzBox•4X (6•4X, X = PF6 - , Cl- ), has been synthesized by connecting an extended viologen (ExBIPY) and a dipyridyl thiazolothiazole (TzBIPY) unit in an end-to-end fashion with two p-xylylene ( p-Xy) linkers...
May 17, 2018: Journal of the American Chemical Society
Zhuang Lv, Liang Zou, Huanjie Wei, Shujuan Liu, Wei Huang, Qiang Zhao
It is very meaningful to develop bifunctional therapeutic agents which can monitor the tumor hypoxia in real time as well as maintain good photodynamic therapy (PDT) effect under hypoxia. To achieve it, herein, a series of hydrophilic phosphorescent starburst Pt(II) porphyrins as bifunctional therapeutic agents for simultaneous tumor hypoxia imaging and highly efficient PDT have been rationally designed and synthesized. They have been obtained by using Pt(II) porphyrins as the functional core and cationic oligofluorenes as the arms...
May 17, 2018: ACS Applied Materials & Interfaces
Swarnava Nandy, Takashi Hisatomi, Song Sun, Masao Katayama, Tsutomu Minegishi, Kazunari Domen
Oxysulfoselenide semiconductor photocatalysts absorb light at longer wavelengths than the corresponding oxysulfides. However, the synthesis of oxysulfoselenides is challenging due to excessive particle growth and the limited availability of metal selenide precursors. In this study, a La5 Ti2 CuS5 O7 (LTCSO) oxysulfide was annealed with Se powder in sealed, evacuated quartz tubes to obtain LTCSO:Se photocatalysts, and the properties of these materials were investigated. Se was found to be incorporated into the LTCSO upon heating at 973 K or higher, and the Se/(S + Se) ratio was increased to a maximum of 0...
May 17, 2018: ACS Applied Materials & Interfaces
Yuichi Kitagawa, Fumiya Suzue, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
A luminescent Eu(iii) complex with a large electronically isolated aromatic ring system, Eu(hfa)3(DPPTO)2 (where hfa denotes hexafluoroacetylacetonate and DPPTO denotes 2-diphenylphosphoryltriphenylene), is reported. The light-harvesting efficiency of the Eu(iii) complex was assessed from electronic absorption spectra. Luminescence properties were evaluated from luminescence spectra, excitation spectra, luminescence quantum yields, and luminescence lifetimes. A remarkably brilliant luminescence was observed because of the strong light absorption and the high luminescence quantum yield of the Eu(iii) complex...
May 17, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiaoling Zhang, Xin Ren, Fang Zhang
Black phosphorus quantum dots (BPQDs) with an average diameter of ≈ 6 nm and a height of ≈1.1 nm are successfully synthesized by using a pulsed laser ablation (PLA) method in isopropyl ether (IPE) solvent. PL quantum yield of the as-prepared sample is as high as 20.7% which is 3 times that of the BPQDs prepared by probe ultrasonic exfoliation (approximately 7.2%) for the first time. The stable and blue-violet photoluminescence (PL) emission of the BPQDs is observed, which is elucidated that electrons transit from the LUMO energy level to the HOMO energy level as well as energy levels below the HOMO ( H1 and H2 )...
May 16, 2018: Chemistry, An Asian Journal
Jacob C Lutter, Svetlana V Eliseeva, Jeff W Kampf, Stéphane Petoud, Vincent Louis Pecoraro
A new family of [3.3.1] metallacryptates with the general composition [LnGa6(H2shi)(Hshi)(shi)7(C5H5N)] (Ln-1; shi3- = salicylhydroximate; Ln = Pr, Nd, Sm - Yb) has been synthesized and characterized. Ln-1 display both interesting magnetic and luminescent properties. Sm-1 has sharp emission bands in the visible and the near-infrared (NIR) regions with quantum yield values ("Q" _"Sm" ^"L" ) of 1.64(9) and 5.5(2).10-2 %, respectively. Tb-1 exhibits a weak green emission ("Q" _"Tb" ^"L" = 1...
May 16, 2018: Chemistry: a European Journal
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