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1.
Leticia Oliveira‐Ferrer Kerstin Schmidt Paul Margaretha 《Helvetica chimica acta》2001,84(12):3818-3821
Cyclohexanones 2b and 2c represent the first examples of nonenolizing 2‐acylcyclohex‐2‐enones, as they bear H‐atoms neither at C(4) or C(6) of the enone ring, nor at the C‐atom vicinal to the exocyclic carbonyl group. While the CF3CO group in 2b (and the Ac group in 2a ) are coplanar to the enone double bonds, the pivaloyl group in 2c , for steric reasons, is out of plane. Compounds 2 exhibit a pronounced sluggishness in both thermal and light‐induced bimolecular reactions. 相似文献
2.
Formation of Fluorinated Amido Esters through Unexpected C3−C4 Bond Fission in 4‐Trifluoromethyl‐3‐oxo‐β‐lactams
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Hang Dao Thi Dr. Hannelore Goossens Dr. Dietmar Hertsen Valerie Otte Prof. Dr. Tuyen Van Nguyen Prof. Dr. Veronique Van Speybroeck Prof. Dr. Matthias D'hooghe 《化学:亚洲杂志》2018,13(4):421-431
4‐Trifluoromethyl‐3‐oxo‐β‐lactams were unexpectedly transformed into 2‐[(2,2‐difluorovinyl)amino]‐2‐oxoacetates as major products, accompanied by minor amounts of 2‐oxo‐2‐[(2,2,2‐trifluoroethyl)amino]acetates, upon treatment with alkyl halides and triethylamine in DMSO. This peculiar C3?C4 bond fission reactivity was investigated in‐depth, from both an experimental and a computational point of view, in order to shed light on the underlying reaction mechanism. 相似文献
3.
Tanmaya Joshi Vanessa Pierroz Cristina Mari Lea Gemperle Stefano Ferrari Gilles Gasser 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(11):3004-3007
Improving the selectivity of anticancer drugs towards cancer cells is one of the main goals of drug optimization; the prodrug strategy has been one of the most promising. A light‐triggered prodrug strategy is presented as an efficient approach for controlling cytotoxicity of the substitutionally inert cytotoxic complex [Ru(dppz)2(CppH)](PF6)2 ( C1 ; CppH=2‐(2‐pyridyl)pyrimidine‐4‐carboxylic acid; dppz=dipyrido[3,2‐a:2′,3′‐c]phenazine). Attachment of a photolabile 3‐(4,5‐dimethoxy‐2‐nitrophenyl)‐2‐butyl (DMNPB) ester (“photocaging”) makes the otherwise active complex C1 innocuous to both cancerous (HeLa and U2OS) and non‐cancerous (MRC‐5) cells. The cytotoxic action can be successfully unleashed in living cells upon light illumination (350 nm), reaching similar level of activity as the parent cytotoxic compound C1 . This is the first substitutionally inert cytotoxic metal complex to be used as a light‐triggered prodrug candidate. 相似文献
4.
《化学:亚洲杂志》2017,12(18):2410-2425
Independent of the substrate structure and reaction conditions, 3‐amino‐2‐cyanothioacrylamides, which contain two active electrophilic centers, were shown to interact with various active halo methylene compounds under mild conditions to afford 5‐acyl‐2‐amino‐3‐cyanothiophenes as the only products. A series of new polyfunctional thiophene derivatives with a rare combination of functionalities were synthesized, and their photophysical properties were experimentally and computationally investigated. The calculated electronic characteristics of the ground and excited states were compared to the experimental results, which provided a good understanding of the relationship between the optoelectronic properties and the molecular structures. After absorption of light quanta, the systems populate an intramolecular charge‐transfer (ICT) Franck–Condon state, and emission occurs from a twisted ICT minimum. 相似文献
5.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(4):357-361
PhotoCORMs (photo‐active CO‐releasing molecules) have emerged as a class of CO donors where the CO release process can be triggered upon illumination with light of appropriate wavelength. We have recently reported an Mn‐based photoCORM, namely [MnBr(pbt)(CO)3] [pbt is 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole], where the CO release event can be tracked within cellular milieu by virtue of the emergence of strong blue fluorescence. In pursuit of developing more such trackable photoCORMs, we report herein the syntheses and structural characterization of two MnI–carbonyl complexes, namely fac‐tricarbonylchlorido[2‐(pyridin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′]manganese(I), [MnCl(C12H8N2S)(CO)3], (1), and fac‐tricarbonylchlorido[2‐(quinolin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′]manganese(I), [MnCl(C16H10N2S)(CO)3], (2). In both complexes, the MnI center resides in a distorted octahedral coordination environment. Weak intermolecular C—H…Cl contacts in complex (1) and Cl…S contacts in complex (2) consolidate their extended structures. These complexes also exhibit CO release upon exposure to low‐power broadband visible light. The apparent CO release rates for the two complexes have been measured to compare their CO donating capacity. The fluorogenic 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole and 2‐(quinolin‐2‐yl)‐1,3‐benzothiazole ligands provide a convenient way to track the CO release event through the `turn‐ON' fluorescence which results upon de‐ligation of the ligands from their respective metal centers following CO photorelease. 相似文献
6.
Three‐Dimensional Ordered Assembly of Thin‐Shell Au/TiO2 Hollow Nanospheres for Enhanced Visible‐Light‐Driven Photocatalysis
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Cao‐Thang Dinh Hoang Yen Prof. Freddy Kleitz Prof. Trong‐On Do 《Angewandte Chemie (International ed. in English)》2014,53(26):6618-6623
An Au/TiO2 nanostructure was constructed to obtain a highly efficient visible‐light‐driven photocatalyst. The design was based on a three‐dimensional ordered assembly of thin‐shell Au/TiO2 hollow nanospheres (Au/TiO2‐3 DHNSs). The designed photocatalysts exhibit not only a very high surface area but also photonic behavior and multiple light scattering, which significantly enhances visible‐light absorption. Thus Au/TiO2‐3 DHNSs exhibit a visible‐light‐driven photocatalytic activity that is several times higher than conventional Au/TiO2 nanopowders. 相似文献
7.
A Single 2‐(2′‐Hydroxyphenyl)benzothiazole Derivative Can Achieve Pure White‐Light Emission
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Jinling Cheng Dr. Di Liu Lijun Bao Kai Xu Dr. Yang Yang Prof. Keli Han 《化学:亚洲杂志》2014,9(11):3215-3220
The synthesis and photophysics of two novel 2‐(2′‐hydroxyphenyl)benzothiazole (HBT) derivatives are presented. The electron‐withdrawing trifluoromethyl (CF3) group in compound 1 facilitates the deprotonation of the phenolic hydroxy group. Well‐resolved triple fluorescence from the enol, keto, and phenolic anion, which ranges from 350 to 600 nm, was detected for 1 in ethanol, which marks the first time triple fluorescence from an excited‐state intramolecular proton transfer (ESIPT) molecule has been reported. Both triphenylamine and CF3 were introduced into derivative 2 . Intramolecular charge transfer and the “red‐edge effect” resulted in the bathochromic shift of dual fluorescence of 2 . Triple fluorescence was also observed for 2 in ethanol. In mixed acetonitrile and ethanol, pure white‐light emission with CIE coordinates of (0.33, 0.33) and a quantum yield of 0.25 was achieved for 2 . This work provides a new avenue for the rational design of an ESIPT molecule to achieve white‐light generation under mild conditions. 相似文献
8.
Helga Szelke gnes Blint Erzsbet Kirly Krisztina Ludnyi Jnos Kovcs Gyrgy Keglevich 《Heteroatom Chemistry》2005,16(3):196-199
A 2‐phosphabicyclo[2.2.2]oct‐7‐ene oxide ( 2 ) and a 2‐phosphabicyclo[2.2.2]octa‐5,7‐diene oxide ( 3 ) with ethyl substituent on the phosphorus atom was synthesized and their fragmentation properties were studied. The phosphabicyclooctadiene oxide ( 3 ) could be utilized in both the UV light‐mediated phosphorylation of simple alcohols and in the thermoinduced phosphorylation of hydroquinone giving an easy access to P‐ethylphosphinates (e.g., 4 and 6 ). The phosphabicyclooctene oxide ( 2 ) was, however, not useful in photoinduced phosphorylations; under such conditions the precursor ( 2 ) underwent dechlorination to afford 5 . © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:196–199, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20093 相似文献
9.
In the present work, 2‐[(E)‐(3‐hydroxynaphthalen‐2‐yl)diazenyl]benzoic acid, an azo chromophoric system was prepared and incorporated onto carbohydrates such as starch and cellulose by dicyclohexylcarbodiimide coupling. The products were characterized by UV‐visible, fluorescence, FT‐IR and NMR spectroscopic methods. The results of the studies show that incorporation of the chromophoric system onto the polymeric core enhanced the light absorption, emission and light stabilization properties of the chromophoric system. The light fastening properties of chromophoric system and the carbohydrate‐bound photochromic systems were compared. It shows that light stabilization of the chromophoric system greatly enhanced on attaching to the polymeric core materials. Thermal stability of the chromophoric system also enhanced on attaching to the biopolymeric core systems. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
Liang Liao Ali Cirpan Liming Ding Frank E. Karasz Yi Pang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(7):2307-2315
New poly(phenylene vinylene) derivatives with a 5‐diphenylamino‐1,3‐phenylene linkage (including polymers 2 , 3 , and 5 ) have been synthesized to improve the charge‐injection properties. These polymers are highly photoluminescent with fluorescent quantum yields as high as 76% in tetrahydrofuran solutions. With effective π‐conjugation interruption at adjacent m‐phenylene units, chromophores of different conjugation lengths can be incorporated into the polymer chain in a controllable manner. In polymer 2 , the structural regularity leads to an isolated, well‐defined emitting chromophore. Isomeric polymer 3 of a random chain sequence, however, allows the effective emitting chromophores to be joined in sequence by sharing a common m‐phenylene linkage (as shown in a molecular fragment). Double‐layer light‐emitting‐diode devices using 2 , 3 , and 5 as emitting layers have turn‐on voltages of about 3.5 V and produce blue‐green emissions with peaks at 493, 492, and 482 nm and external quantum efficiencies up to 1.42, 0.98, and 1.53%, respectively. In comparison with a light‐emitting diode using 2 , a device using 3 shows improved charge injection and displays increased brightness by a factor of ~3 to 1400 cd/m2 at an 8‐V bias. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2307–2315, 2006 相似文献
11.
Jianfu Ding Zhao Li Zhe Cui Gilles P. Robertson Naiheng Song Xiaomei Du Ludmila Scoles 《Journal of polymer science. Part A, Polymer chemistry》2011,49(15):3374-3386
We demonstrated, for the first time, that 3,6‐bis(3‐hexylthien‐2‐yl)‐s‐tetrazine (TTz) with hexyl group at the 3‐position of thiophene rings can be prepared using a modified sulfur‐assisted Pinner synthesis. Although the hexyl group creates large steric hindrance to the tetrazine ring formation reaction, and the reaction under a traditional condition only produces trace amount of the target product, the yield of this reaction under a modified reaction condition using anhydrous hydrazine at 68 °C can reach 65%. Two new copolymers of the resulting TTz and hexyl‐ or 2‐ethylhexyl‐substituted cyclepentadithiophene have been prepared. The polymers show a broader light absorption in film than in solution attributing to the large distribution of effective conjugation length of polymer chain due to the existence of both cis‐ and trans‐orientations of the 3‐hexylthiophene units in the planar polymer chain in solid state. Although the polymers show a narrow band gap and a deep HOMO level, which are desirable for generating an efficient light absorption and a larger open circuit voltage (Voc) of the resulting solar cell devices, the device performance is not as good as expected. It is attributed to the random distribution of the cis‐ and trans‐conformations along the polymer chain. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
12.
Kyung Moon Jung Kyung Hwan Kim Jung‐Il Jin Min Ju Cho Dong Hoon Choi 《Journal of polymer science. Part A, Polymer chemistry》2008,46(22):7517-7533
New deep‐red light‐emitting phosphorescent dendrimers with hole‐transporting carbazole dendrons were synthesized by reacting tris(2‐benzo[b]thiophen‐2‐yl‐pyridyl) iridium (III) complex with carbazolyl dendrons by DCC‐catalyzed esterification. The resulting first‐, second‐, and third‐generation dendrimers were found to be highly efficient as solution‐processable emitting materials and for use in host‐free electrophosphorescent light‐emitting diodes. We fabricated a host‐free dendrimer EL device with configuration ITO/PEDOT:PSS (40 nm)/dendrimer (55 nm)/BCP (10 nm)/Alq3 (40 nm)/LiF (1 nm)/Al (100 nm) and characterized the device performance. The multilayered devices showed luminance of 561 cd/m2 at 383.4 mA/cm2 (12 V) for 15 , 1302 cd/m2 at 321.3 mA/cm2 (14 V) for 16 , and 422 cd/m2 at 94.4 mA/cm2 (18 V) for 17 . The third‐generation dendrimer, 17 (ηext = 6.12% at 7.5 V), showed the highest external quantum efficiency (EQE) with an increase in the density of the light‐harvesting carbazole dendron. Three dendrimers exhibited considerably pure deep‐red emission with CIE 1931 (Commission International de L'Eclairage) chromaticity coordinates of x = 0.70, y = 0.30. The CIE coordinates remained very stable with the current density. The integration of rigid hole‐transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution‐processable materials for dendrimer light‐emitting diode (DLED) applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7517–7533, 2008 相似文献
13.
Nicolas Cocherel Cyril Poriel Dr. Joëlle Rault‐Berthelot Dr. Frédéric Barrière Dr. Nathalie Audebrand Dr. Alexandra M. Z. Slawin Prof. Dr. Laurence Vignau Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(36):11328-11342
New routes to ladder‐type phenylene materials 1 and 2 are described. The oligomers 1 and 2 , which possess a “3π‐2spiro” architecture, have been synthesized by using extended diketone derivatives 3 and 10 as key intermediates. The physicochemical properties of the new blue‐light emitter 2 were studied in detail and compared with those of the less‐extended 1 . Owing to the recent development of fluorenone derivatives and their corresponding more conjugated analogues as potential electron‐transport materials in organic light‐emitting diodes (OLEDs) and as n‐type materials for photovoltaic applications, we also report herein the thermal, optical and electrochemical behavior of the key intermediates, diketones 3 and 10 . Finally, the application of dispiro 2 as a new light‐emitting material in OLEDs is reported. 相似文献
14.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(3):740-745
White‐light‐emitting materials with high mobility are necessary for organic white‐light‐emitting transistors, which can be used for self‐driven OLED displays or OLED lighting. In this study, we combined two materials with similar structures—2‐fluorenyl‐2‐anthracene (FlAnt) with blue emission and 2‐anthryl‐2‐anthracence (2A) with greenish‐yellow emission—to fabricate OLED devices, which showed unusual solid‐state white‐light emission with the CIE coordinates (0.33, 0.34) at 10 V. The similar crystal structures ensured that the OTFTs based on mixed FlAnt and 2A showed high mobility of 1.56 cm2 V−1 s−1. This simple method provides new insight into the design of high‐performance white‐emitting transistor materials and structures. 相似文献
15.
《化学:亚洲杂志》2017,12(17):2172-2176
Hydrothermal reactions of metal nitrates and ligand bis(5‐(pyridine‐2‐yl)‐1,2,4‐triazol‐3‐yl)methane (H2L1) gave three cluster compounds, {Cr2}, {Zn12} and {Fe8}. Notably, methylene group of H2L1 was in situ oxidized either to hydroxymethylated (L2‐O)3− in the metallo‐ring {Zn12} or to a rigid carbonylated (L3=O)2− in the screw‐type {Fe8}. In light of comparative experimental results, NO3− was deduced to be of a catalytic role in the ligand oxidation. Metal ion could be regarded as an “induced” tool for clusters generation in self‐assembly process. 相似文献
16.
Aqueous self‐assembly of pullulan‐b‐poly(2‐ethyl‐2‐oxazoline) double hydrophilic block copolymers
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Jochen Willersinn Bernhard V. K. J. Schmidt 《Journal of polymer science. Part A, Polymer chemistry》2017,55(22):3757-3766
The self‐assembly of a novel double hydrophilic block copolymer in water without the application of external triggers is described, namely pullulan‐b‐poly(2‐ethyl‐2‐oxazoline) (Pull‐b‐PEtOx). The biomacromolecules, Pull (8–38 kg mol?1), is modified and conjugated to biocompatible PEtOx (22 kg mol?1) via modular conjugation. Moreover, the molecular weight of the Pull blocks are varied to investigate the effect of molecular weight on the self‐assembly behavior. Spherical particles with sizes between 300 and 500 nm are formed in diluted aqueous solution (0.1–1.0 wt %) as observed via dynamic light scattering and static light scattering. Additionally, cryo scanning electron microscopy and laser scanning confocal microscopy are performed to support the finding from light scattering. The block ratio study shows an optimum ratio of Pull and PEtOx of 0.4/0.6 for self‐assembly in water in the concentration range of 0.1–1.0 wt %. At higher concentrations of 20 wt %, vesicular structures with sizes above 1 µm can be observed via optical microscopy. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3757–3766 相似文献
17.
The Synthesis of New Heterocycles Using 2‐(4‐Chloro‐1,3‐dihydro‐3,3,7‐trimethyl‐2H‐indol‐2‐ylidene) Propanedial
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Maryam Alyari Mehdi M. Baradarani Arash Afghan John A. Joule 《Journal of heterocyclic chemistry》2014,51(3):854-859
4‐Chloro‐2,3,3,7‐tetramethyl‐3H‐indole (an indolenine) was produced by the reaction of 5‐chloro‐2‐methylphenylhydrazine hydrochloride with 3‐methylbutan‐2‐one via Fischer reaction. Exposure of the indolenine to the Vilsmeier reagent at 50°C produced a β‐diformyl compound, 2‐(4‐chloro‐1,3‐dihydro‐3,3,7‐trimethyl‐2H‐indol‐2‐ylidene)propanedial. This dialdehyde was reacted with arylhydrazines, acetamidinium chloride, urea, thiourea, guanidinium chloride, and cyanoacetamide to give various 5‐membered and 6‐membered heterocyclic products, each carrying a 4‐chloro‐3,3,7‐trimethyl‐3H‐indol‐2‐yl unit as a substituent, in excellent yields. 相似文献
18.
A Metal‐free Approach to 3‐Aryl‐3‐hydroxy‐2‐oxindoles by Treatment of 3‐Acyloxy‐2‐oxindoles with Diaryliodonium Salts
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A mild, metal‐free approach has been realized for the facile construction of highly valuable 3‐(hetero)aryl‐3‐hydroxy‐2‐oxindoles. Direct arylations of 3‐acyloxy‐2‐oxindoles with diaryliodonium salts as arylation reagents are implemented in the presence of K2CO3 at room temperature without using an organometallic promoter to deliver an array of 3‐(hetero)aryl‐3‐hydroxy‐2‐oxindoles in good yields. 相似文献
19.
Vratislav Langer Miroslav Ko Dalma Gyepesov Juraj Kronek Jozef Lusto Mariana Sldkovi
ov 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o602-o606
Crystal structures are reported for three isomeric compounds, namely 2‐(2‐hydroxyphenyl)‐2‐oxazoline, (I), 2‐(3‐hydroxyphenyl)‐2‐oxazoline, (II), and 2‐(4‐hydroxyphenyl)‐2‐oxazoline, (III), all C9H9NO2 [systematic names: 2‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (I), 3‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (II), and 4‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O—H⋯N hydrogen bond. Surprisingly, the 2‐oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2‐oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C—H⋯N hydrogen bonds. In (III), strong intermolecular O—H⋯N hydrogen bonds and weak intramolecular C—H⋯O hydrogen bonds lead to the formation of an infinite chain of molecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions. 相似文献
20.
Svitlana V. Shishkina Irina S. Konovalova Pavlo V. Trostianko Anna O. Geleverya Sergiy M. Kovalenko Natalya D. Bunyatyan 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(11):1541-1553
This study of 3‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)‐2H‐chromen‐2‐one, C17H10N2O3, 1 , and 3‐[5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl]‐2H‐chromen‐2‐one, C16H9N3O3, 2 , was performed on the assumption of the potential anticancer activity of the compounds. Three polymorphic structures for 1 and two polymorphic structures for 2 have been studied thoroughly. The strongest intermolecular interaction is stacking of the `head‐to‐head' type in all the studied crystals. The polymorphic structures of 1 differ with respect to the intermolecular interactions between stacked columns. Two of the polymorphs have a columnar or double columnar type of crystal organization, while the third polymorphic structure can be classified as columnar‐layered. The difference between the two structures of 2 is less pronounced. Both crystals can be considered as having very similar arrangements of neighbouring columns. The formation of polymorphic modifications is caused by a subtle balance of very weak intermolecular interactions and packing differences can be identified only using an analysis based on a study of the pairwise interaction energies. 相似文献