共查询到20条相似文献,搜索用时 15 毫秒
1.
Kevin D. Belfield Mykhailo V. Bondar Florencio E. Hernandez Olga V. Przhonska Sheng Yao 《Chemical physics》2006,320(2-3):118-124
Linear spectral properties, including excitation anisotropy, of pseudoisocyanine or 1,1′-diethyl-2,2′-cyanine iodide (PIC) J-aggregates in aqueous solutions with J-band position at 573 nm were investigated. Two-photon absorption of PIC J-aggregates and monomer molecules was studied using an open aperture Z-scan technique. A strong enhancement of the two-photon absorption cross-section of PIC in the supramolecular J-aggregate assembly was observed in aqueous solution. This enhancement is attributed to a strong coupling of the molecular transition dipoles. No two-photon absorption at the peak of the J-band was detected. 相似文献
2.
LI QianQian ZHONG AoShu LIU HaiJie PENG Ming LIU Jun PEI ZhiGuo HUANG ZhenLi QIN JinGui & LI Zhen 《中国科学B辑(英文版)》2011,(4)
A series of V-type chromophores with electron-rich heterocyclevinylene bridges have been synthesized via Wittig-Horner-Emmons and Vilsmeier reactions.All the target chromophores showed strong one-photon and two-photon excited emission,and their electron properties could be tuned by using different heterocycles such as furan,thiophene and pyrrole moieties in I-III.The maximum two-photon absorption (TPA) cross sections occurred at 760 nm and were measured to be in the range of 400-800 GM. 相似文献
3.
The synthesis and characterization of new 1,10-phenanthroline-based chromophores LT1, LT2 and LD1 featuring fluorene unit(s) are reported. Their absorption and emission as well as their two-photon absorption properties in the 450-650 nm spectral range are discussed in comparison with the parent 1,10-phenanthroline and already described ligands L1 and L2. 相似文献
4.
Olivier Mongin Muniappan Sankar Marina Charlot Youssef Mir Mireille Blanchard-Desce 《Tetrahedron letters》2013
The synthesis and photophysical properties of new multiporphyrin assemblies are described. Their design, based on a smooth electronic disconnection between two-photon absorbing (2PA) octupolar or quadrupolar cores and the peripheral porphyrins, leads to a major increase in (non-resonant) 2PA responses in the NIR, while fully retaining the fluorescence and photosensitization properties of isolated porphyrins. This approach, which involves electronic coupling of semi-disconnected moieties in the higher excited states of the synergic systems, is of interest to fully benefit from the advantages of selective 2PA for application in combined two-photon high resolution imaging and photodynamic therapy. 相似文献
5.
A novel one-pot two-step protocol has been developed to synthesize various spiro[benzofuran-2,2′-naphthalen]-1′-one derivatives from the three-component reaction of tetralones, 2-hydroxyphenyl functionalized α,β-unsaturated ketones, and iodine. One C–C bond and one C–O bond have formed during this process. The notable features of this protocol are simple and mild reaction conditions, applicable to a wide range of readily available starting materials, good yields (up to 91%), and excellent stereoselectivities (up to 97:3). 相似文献
6.
Two new D-π-A organic chromophores, 1,2,4,5-tetra(4-cyanophenyl)pyrrolo[3,2-b]pyrrole (4CNPP) and 1,2,3,4,5,6-hexa(4-cyanophenyl)pyrrolo[3,2-b]pyrrole (6CNPP), were developed by modifying the electron-rich pyrrolo[3,2-b]pyrrole (PP) unit with four and six 4-cyanophenyls respectively. The compounds exhibited bright blue emissions in low- to high-polarity solvents, with high Фfs of 88–90% in toluene, as well as impressive two-photon absorption cross-sections at the near-infrared (NIR) 700?nm. 相似文献
7.
Shinya Tanaka 《Tetrahedron letters》2007,48(43):7660-7664
Treatment of 1,3-bistriflate esters of thiacalix- (6a) and calix[4]arenes 6b with benzylamine in the presence of CuI and K3PO4 results in the displacement of a TfO moiety with a benzylamino group, which provides an easy access to monoaminothiacalix[4]arene 4a and its methylene-bridged counterpart 4b. On the other hand, the reaction of 6a in the absence of benzylamine leads to intramolecular dietherification, giving 4,4′:6,6′-diepithiobis(phenoxathiine) 7a. 相似文献
8.
Tanmay Chatterjee 《Tetrahedron letters》2010,51(52):6906-6910
Two symmetrical and one unsymmetrical ‘push-pull’ amphiphilic 2,2′-bipyridine chromophores have been synthesized through Horner-Wordsworth-Emmons and Knoevenagel reaction mechanized synthetic protocols and characterized by spectroscopy. Linear optical properties and thermal stability of the synthesized chromophores have been investigated. 相似文献
9.
A novel multi-branched chromophore containing 2,3-diarylquinoxalinyl units as the electron-acceptors had been synthesized and its nonlinear optical properties were characterized in the femtosecond and nanosecond regime. The experimental results show that the studied fluorophore possesses strong and wide-dispersed two-photon absorption in near infrared (NIR) region. It is demonstrated that the incorporation of 2,3-disubstituted quinoxaline moieties as a part of π-conjugation in a dye molecule could be a useful approach toward large molecular two-photon absoptivities within the studied spectral region. Effective optical-power-attenuation behaviors in the nanosecond time domain of this compound were also investigated and the results indicate that such dye molecule can be a potential material as a broadband and quick-responsive optical limiter especially when against those laser lights with longer pulses. 相似文献
10.
Jari Hovinen 《Tetrahedron letters》2004,45(29):5707-5709
Treatment of 2,6-di(pyridin-2-yl)pyridin-4(1H)-one with various appropriately protected ω-substituted primary alcohols or a nucleoside (3,3′-O-diBz-dUrd) in dry THF in the presence of triphenylphosphine and diisopropylazodicarboxylate gives the corresponding 4′-substituted terpyridines in high yield. 相似文献
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12.
Majid M. Heravi Ali Kivanloo Mehdi Bakavoli Bernhard Neumüller 《Tetrahedron letters》2005,46(10):1607-1610
The reaction of 3-mercaptopropargyl-1,2,4-triazoles with various iodobenzenes catalyzed by Pd-Cu leads to the regioselective formation of 6-benzylthiazolo[3,2-b]1,2,4-triazoles 4. The structure of 4d was confirmed by X-ray analysis. 相似文献
13.
Reactions of 3-substituted-2-chloroquinoxalines, terminal alkynes, and 1,3-dicarbonyl compounds in the presence of palladium catalyst afforded a number of 6,8,9-trisubstituted-10H-pyrido[1,2-a]quinoxalin-10-ones in 60–86% reaction yields. This one-pot protocol provided an efficient, practical, and direct method for the synthesis of pyrido[1,2-a]quinoxalines from readily available starting materials in the absence of a copper salt. 相似文献
14.
Alexandru C. Razus Claudia Pavel Oana Lehadus Simona Nica Liviu Birzan 《Tetrahedron》2008,64(8):1792-1797
The synthesis of a new biazulenyl system, which contains azulene moieties coupled in 1- and 6-position is reported. The structure of the isolated compounds, as well as the calculated dihedral angle between the planes of the coupled moieties, has been correlated with the recorded spectra. 相似文献
15.
2,2′-Diamino-1,1′-biaryls were found to undergo ring-closure condensation reaction to afford benzo[c]carbazoles in good to excellent yield. Coupled with the synthesis of 2,2′-biaryldiamines from diaryl hydrazides via [3,3]-sigmatropic rearrangement, it constitutes a new efficient synthetic method for benzo[c]carbazoles and related compounds. 相似文献
16.
Laurent PellegattiEmeline Vedrenne Marie-Aude HiebelFrédéric Buron Stéphane MassipJean-Michel Leger Christian JarrySylvain Routier 《Tetrahedron letters》2011,52(41):5224-5228
An efficient and original Ugi multicomponent reaction of aminopyridines and aminopyrimidines is reported. Starting from aminotetrazine 6 or 7, an isocyanide and an ortho-carboxybenzaldehyde, tetrazinoimidazoisoquinolinones were isolated, after few minutes of microwave irradiation, in good to excellent yields. The scope of this method was extended by using different isocyanides. 相似文献
17.
In this paper we report regioselective tandem metal-catalyzed aminations on dihaloquinolines (2-chloro-3-iodoquinoline and 2,3-dibromoquinoline) with amino(benzo)(di)azines. Eight new heterocyclic scaffolds of the dipyridoimidazole type could be synthesized. By controlling the reaction temperature selective C-2 intermolecular Pd-catalyzed amination on 2,3-dibromoquinoline with amino(benzo)(di)azines can be achieved. 相似文献
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19.
K.C. Majumdar Shovan Mondal Nirupam De Randhir Kumar Sinha Nilasish Pal B. Roy 《Tetrahedron letters》2010,51(3):521-524
Design and synthesis of cholesterol based disk-like liquid crystalline compounds using triphenylamine as a core moiety have been achieved by Pd-catalyzed cross-coupling reaction. The newly synthesized compounds exhibit a cholesteric phase with fingerprint texture as well as oily texture. In the low temperature region, there is a signature of smectic B with characteristic dendritic and mosaic textures. The mesogenic properties were characterized by polarizing microscopy, differential scanning calorimetry and HRXRD studies. 相似文献
20.
Issa Yavari Farough Nasiri Loghman Moradi Hoorieh Djahaniani 《Tetrahedron letters》2004,45(38):7099-7101
Reaction of tert-butyl isocyanide with electron-deficient acetylenic esters in the presence of N1-[(Z)-1-benzoyl-3-oxo-3-phenyl-1-propenyl]-2-(2-furyl)-2-oxoacetamide leads to dialkyl 5-tert-butylamino-[2,2′]bifuranyl-3,4-dicarboxylates in moderate yields. 相似文献