Dipolar 3-methoxychromones as bright and highly solvatochromic fluorescent dyes

Herein, three environment-sensitive (solvatochromic) fluorescent dyes presenting a strong electron acceptor 3-methoxychromone unit and varied electron donor 2-aryl were developed. All three dyes showed remarkable polarity-dependent shifts of the emission maximum, which increase with extension of the dye conjugation. For the 3-methoxychromone bearing a 7-(diethylamino)-9,9-dimethylfluoren-2-yl donor group the difference between the excited and the ground state dipole moments, estimated from the Lippert-Mataga expression, reached 20 D, which is among the largest reported for neutral dipolar fluorophores. Moreover, the new dyes are characterized by significant two-photon absorption cross-section (up to 450 GM) and large fluorescence quantum yields. The strong decrease in the fluorescence quantum yields of the dyes in polar protic solvents was observed together with the increase in the non-radiative deactivation rates, which can originate from twisted intramolecular charge transfer and intermolecular proton transfer phenomena. In comparison to the parent 3-hydroxychromone derivatives, the new dyes presented significantly improved photostability, which confirms that photodegradation of 3-hydroxychromones occurs from a product of the excited-state intramolecular proton transfer (phototautomer). Finally, an application of the new dyes for probing local binding site polarity of serum albumin was shown. This new class of fluorescent dyes may serve as attractive building blocks for future molecular sensors utilizing environment-sensitive fluorophores.     

两个新的苯并噻唑衍生物的合成与光物理性质

以苯并噻唑、苯乙酰基和吡啶阳离子为电子受体,二乙烯基苯为共轭桥,合成了两个新的A-π-A′型苯并噻唑衍生物:4-(2-苯并噻唑)-乙烯基查尔酮(1)和4-{4-[2-(苯并噻唑)乙烯基]苯乙烯基}-N-甲基吡啶碘盐(2).研究了它们在溶液和固体基质中的光物理性质.研究发现:染料2由于具有较强的极性和较好的平面性,从而具有较长的吸收、发射峰和较强的荧光发射.有机染料在聚甲基丙烯酸甲酯/溶胶-凝胶复合玻璃中的发光行为与聚甲基丙烯酸甲酯和溶胶-凝胶玻璃二者的基质性质有关,同时由于固体基质中分子发生聚集的可能性降低,荧光强度相对于同浓度溶液增强,稳定性提高.     

Synthesis and absorption spectra of 2-substituted 5,8-dimethoxy-4H-1-benzothiopyran-4-one 1,1-dioxides

2,3-Dibromo-5,8-dimethoxy-4H-1-benzothiopyran-4-one (thiochromone) 1,1-dioxide which was a starting material to prepare sulfone analogues of 1,4-naphthoquinone dyes was easily prepared from 5,8-dimethoxythiochroman-4-one by oxidation and bromination. The reactions of 2,3-dibromo-5,8-dimethoxythiochromone 1,1-dioxide 4 with aliphatic and aromatic amines in ethanol below 20° gave 2-substituted derivatives 12a-e and at higher reaction temperature the amination gave 2-arylamino derivatives 13c-e debrominated at C -3. The visible absorption spectra of these derivatives were investigated by the PPP MO method.     

Density functional theory as a guide for the design of pyran dyes for dye-sensitized solar cells

Abstract  

Using density functional theory and hybrids, we examined several derivatives of the dye 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran, with the objective of identifying modifications which would improve the properties of dyes for dye-sensitized solar cells. We calculated the electronic structure of numerous derivatives at the HOMO and LUMO energy levels, with the hypothesis that directing the flow of excited electrons to the point of the dye at which the molecule attaches to TiO₂ would increase the energy conversion efficiency of the cell. We also examined the UV–visible absorption spectra of the dyes, with the objective of capturing the maximum amount of solar light. By use of the derivatives we compared the use of two electron-donating groups instead of one, extension of the conjugated chain leading to the attachment point of the dye, use of oxygen versus sulfur or selenium in the dye, and the use of different electron-donating groups. We identified several promising donating groups and determined that the other modifications to the dye are likely to increase solar cell efficiency.     

Selenonaphtheno[2,3-d]thiazole derivatives as polymethine dyes

New polymethine dyes — selenonaphtheno[2,3-d]thiazole derivatives — were synthesized. It is shown that all of the synthesized dyes which have a selenonaphtheno[2,3-d]thiazole residue are more deeply colored than the corresponding 6,7-benzobenzothiazole and thionaphtheno[2,3-d] thiazole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 459–461, April, 1971.     

Exploration on Charge Transfer and Absorption Spectra of Spiro[fluorene-9,90-xanthene]-based Polyoxometalate Hybrids Toward High Performance Dye-sensitized Solar Cell

Based on spiro[fluorene-9,90-xanthene](SFX, dye 1), the Lindqvist-type polyoxometalate(POM) functionalized with SFX and its derivatives(dyes 2-4) used in dye-sensitized solar cells(DSSCs) were designed and investigated with the density functional theory(DFT) and time-dependent DFT(TD-DFT) calculations. The results indicate that Lindqvist-type POM is the main contribution to the lowest unoccupied molecular orbital(LUMO) and affects the LUMO energies of dyes 2-4. The maximum absorptions of the designed dyes containing POM(dyes 2-4) are red shifted comparing with that of dye 1. The introduction of electron-donating group onto SFX segment is helpful to red shift the absorption spectra. The major factors affecting the performance of DSSCs, including light harvesting and electron injection were evaluated. Considering the absorption spectra and photovoltaic parameters, dyes 3 and 4 are promising high performance dye sensitizers in n-type DSSCs.     

3-Amino-2,1-benzoisothiazole. Synthesis of some chloro and trifluoromethyl derivatives

The syntheses of the 7-chloro-, 4,7-dichloro-, 5- and 7-trifluoromethyl, 5-chloro-6-trifluoro-methyl- and 5-chloro-7-trifluoromethyl- derivatives of 3-amino-2,1-benzoisothiazole are described. Preparative details are included for a number of the precursors to the benzoisothiazole derivative which have not previously been described. Visible spectra of some azo dyes prepared from the title compounds with a selected coupler are discussed with reference to the substituent effects.     

Polymethine dyes which are derivatives of heterocyclic bases containing condensed thiophene rings

Some new polymethine dyes of the cyanine and merocyanine series, containing thieno[2, 3-b]thieno[2, 3-b]pyridine-4 and thieno[3, 2-b]-thieno[2, 3-b]-pyridine-8 groups are synthesized. Replacement of the vinylene group by a sulfur atom in the condensed benzene rings of the 5, 6-benzoquinoline-4 group in dyes which are derivatives of this base, results in a marked hypsochromic shift of the absorption maximum of the corresponding dyes.For Part IV see [8].     

Natural dyes based on chlorophyll and protoporphyrin derivatives

The utility of natural dyes (chlorophyll, protoporphyrin, and their derivatives) as ecologically pure new-generation dyes that are safer than common synthetic arene-based dyes is discussed. New dyes were obtained from chlorophyll and protoporphyrin derivatives such as pheophorbide (a+b), chlorin e₆, 6-N-(2-aminoethylamido)chlorin e₆ dimethyl ester, and 6-N-(2-aminoethylamido)deuteroporphyrin methyl ester and tested in coloration of wool, cotton, and acetate fibers.     

蓝光有机存储染料研究进展

近年来,蓝光有机存储染料作为超高密度存储技术的核心已经日益受到人们的广泛关注,出现了与之相关的大量专利文献报道.本文介绍了卟啉染料、偶氮染料、菁染料、芪类染料和香豆素衍生物染料等蓝光染料的合成及应用,并对蓝光有机存储染料的发展趋势作了展望.     

Synthesis and use of ecologically pure metal-containing dyes based on chlorophyll derivatives

The problem of the use of a natural pigment, chlorophyll, as ecologically pure dye for textile fibers is discussed. The physicochemical principles of the synthesis of metalocontaining compounds based on chlorophyll derivatives used for development of chlorophyll and porphyrin dyes of new generation, which are more ecologically safe than the arene-based dyes.     

Dibenzothiophene Sulfone Derivatives as Plasma Membrane Dyes

Dibenzothiophene 5,5-dioxide (DBTOO) derivatives have recently been shown to processes utility as fluorescent cell dyes. In an effort to extend the functionality of DBTOO-based dyes to include the visualization of cellular membranes, two lipophilic DBTOO were synthesized and their ability to incorporate into the plasma membrane of HeLa cells was examined by fluorescent microscopy. The photophysical properties of the two new DBTOO derivatives were determined and both have good fluorescent quantum yields and a visible blue emission. Due to agreeable wavelengths of excitation and emission, a standard 4′,6-diamindino-2-phenylindole (DAPI) filter set worked well with these dyes. After co-staining, it was confirmed that both DBTOO dyes localized in the plasma membrane. The quality of the overlap was quantified using Pearson correlation coefficient, which indicated a strong overlap between the DBTOO dyes and the standard plasma membrane dye. The novel dyes also displayed relatively low toxicity to the HeLa cells with IC₅₀ between 10 and 100 µm . Thus, this work reports a new use of DBTOO derivatives as fluorescent microscopy stains.     

Ionic liquid 1-(3-Trimethoxysilylpropyl)-3-methylimidazolium nitrite as a new reagent for the efficient diazotization of aniline derivatives and in situ synthesis of azo dyes

A new ionic liquid 1-(3-trimethoxysilylpropyl)-3-methylimidazolium nitrite was synthesized. This ionic liquid was used as a convenient nitrosonium source in diazotization of arylamines into their corresponding diazonium salts which were converted into their related azo dyes via the in situ azo-coupling with aniline derivatives or phenolic compounds. The diazotization of anilines in this ionic liquid and subsequent azo-coupling generated the related azo dyes in good to excellent yields at 0?C5 °C in short reaction times via a simple experimental procedure.     

l, 9-Substituted fluorenes

The synthesis of 2-methyl (phenyl)-2, 3H-pyridazino-[4, 5, 6-m- l] fluorene-3-methylthionium methylsulfates and of derivatives with substituents in the fluorene ring, is described. Reaction of the latter with heterocyclic hydrazones, and also with compounds containing an active methylene or methyl group, gives cyanine dyes. The electronic spectra of the dyes are measured.For Part III see [3].     

Ultrafast excited-state dynamics of oxazole yellow DNA intercalators

The excited-state dynamics of the DNA intercalator YO-PRO-1 and of three derivatives has been investigated in water and in DNA using ultrafast fluorescence spectroscopy. In the free form, the singly charged dyes exist both as monomers and as H-dimers, while the doubly charged dyes exist predominantly as monomers. Both forms are very weakly fluorescent: the monomers because of ultrafast nonradiative deactivation, with a time constant on the order of 3-4 ps, associated with large amplitude motion around the methine bridge, and the H-dimers because of excitonic interaction. Upon intercalation into DNA, large amplitude motion is inhibited, H-dimers are disrupted, and the molecules become highly fluorescent. The early fluorescence dynamics of these dyes in DNA exhibits substantial differences compared with that measured with their homodimeric YOYO analogues, which are ascribed to dissimilarities in their local environment. Finally, the decay of the fluorescence polarization anisotropy reveals ultrafast hopping of the excitation energy between the intercalated dyes. In one case, a marked change of the depolarization dynamics upon increasing the dye concentration is observed and explained in terms of a different binding mode.     

Cyclobutenediylium Dyes

In agreement with the aromaticity and electrophilic behavior of squaric acid, a cyclobutenediyliumtetroxide ion is formulated as a limiting form of the squarate dianion. These views are confirmed by the structure of a series of new compounds that are readily obtainable from squaric acid or its derivatives, and most of which are deeply colored. The compounds contain the cyclobutenediyliumdioxide grouping as the chromophore, and form a new class of dyes, for which the name cyclobutenediylium dyes is proposed.     

New Dyes Based on Extended Fulvene Motifs: Synthesis through Redox Reactions of Naphthoquinones with Donor–Acceptor Cyclopropanes and Their Spectroelectrochemical Behavior

Novel dyes based on extended fulvene motifs are reported. The carbon skeleton was generated by a catalyzed addition of donor–acceptor cyclopropanes to naphthoquinone. The hydroxy group at the central ring of the tricyclic fulvene motif was converted into the triflate, which reacted efficiently with a wide range of nucleophiles, resulting in substitution and thereby providing new derivatives. The synthetic versatility allowed us to investigate the absorption, electrochemical, and UV/Vis-NIR spectroelectrochemical properties of these dyes as a function of the substituents. The dyes were shown to participate in reductive electrochemistry, the reversibility of which can be improved by appropriate selection of the substituents. Additionally, first signs of NIR electrochromism are presented, opening new avenues for the future investigations of such dyes.     

In situ preparation of highly fluorescent dyes upon photoirradiation

Photoswitchable or photoactivatable fluorescent dyes are potentially applicable to ultrahigh density optical memory media as well as super-resolution fluorescence imaging when the dyes are highly fluorescent and have large absorption coefficients. Here, we report on highly fluorescent photochromic dyes, which are initially nonluminous in solution under irradiation with visible light but activated to emit green or red fluorescence upon irradiation with ultraviolet (UV) light. The dyes 5a-9a are sulfone derivatives of 1,2-bis(2-ethyl-6-phenyl(or thienyl)-1-benzothiophen-3-yl)perfluorocyclopentene. It was found that substitution of phenyl or thiophene rings at 6 and 6' positions of the benzothiophene-1,1-dioxide groups is effective to increase the fluorescence quantum yields of the closed-ring isomers over 0.7 and absorption coefficients over 4 × 10(4) M(-1) cm(-1). The phenyl-substituted derivatives 5a-7a undergo photocyclization reactions to produce yellow closed-ring isomers 5b-7b, which emit brilliant green fluorescence at around 550 nm (Φ(F) = 0.87-0.88) under irradiation with 488 nm light. Any absorption intensity change of the closed-ring isomers was not observed even after 100 h storage in the dark at 80 °C. The closed-ring isomers slowly returned to the initial open-ring isomers upon irradiation with visible (λ > 480 nm) light. The ring-opening quantum yields (Φ(C→O)) were measured to be (1.6-4.0) × 10(-4). When the phenyl substituents are replaced with thiophene rings, such as compounds 8a and 9a, the absorption bands of the closed-ring isomers shift to longer than 500 nm. The closed-ring isomers exhibit brilliant red fluorescences at around 620 nm (Φ(F) = 0.61-0.78) under irradiation with 532 nm light. The ring-opening reactions are very slow (Φ(C→O) < 1 × 10(-5)). The fluorescence lifetimes of these sulfone derivatives were measured to be around 2-3 ns, which is much longer than the value of the closed-ring isomer of 1,2-bis(2-methyl-1-benzothiophen-3-yl)perfluorocyclopentene (τ(F) = 4 and 22 ps). The closed-ring isomer 8b in 1,4-dioxane exhibits excellent fatigue resistant property under irradiation with visible light (λ > 440 nm) superior to the stability of Rhodamine 101 in ethanol.     

Phototoxicity of Some Bromine-Substituted Rhodamine Dyes: Synthesis, Photophysical Properties and Application as Photosensitizers

Abstract— The synthesis of some bromine-substituted rhodamine derivatives viz. , 4,5-dibromorhodamine methyl ester (dye 2) and 4,5-dibromorhodamine n -butyl ester (dye 3) are reported. These dyes were synthesized to promote a more efficient cancer cell photosensitizer for potential use in in vitro bone marrow purging in preparation for autologous bone marrow transplantation. Spectroscopic and photo-physical characterization of these dyes together with rhodamine 123 (dye 1) are reported in water, methanol, eth-anol and also in a microheterogeneous system, sodium dodecyl sulfate. The possible mechanism of photosensi-tization is characterized in terms of singlet oxygen efficiency of these dyes. Singlet oxygen quantum yields for bromine-substituted dyes are in the range of 0.3-0.5 depending on the solvent. For dye 1 no singlet oxygen production is found. The photodynamic actions of these dyes in different cell lines are tested. It was found that dye 2 and dye 3 are efficient photosensitizers and mediate eradication of K562, EM2, myeloid cell lines (CML) and the SMF-AI rhabdomyosarcoma line.