Synthesis and absorption-fluorescence properties of

1,4-Bis(²-pyrazolin-3-yl)benzene derivatives were synthesized by the reaction of dibenzal-p-diacetylbenzene or 1,4-bis(-dimethylaminopropionyl)benzene with various hydrazines. Some of these derivatives were converted to the corresponding 1,4-bis(3-pyrazolyl)benzene derivatives by oxidative dehydrogenation with sulfur. The absorption and fluorescence spectra of the synthesized compounds were measured, and the fluorescence quantum yields were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–83, January, 1980.     

Competitive One-Pot Reactions: Simultaneous Synthesis of Decahydroacridine-1,8-diones and 1,8-Dioxo-octahydroxanthenes and Photophysical Characterization

A simple and convenient one-pot method for simultaneously obtaining decahydroacridine-1,8-diones and 1,8-dioxo-octahydroxanthene derivatives is described. A high conversion yielding both products was obtained under the reaction conditions. To understand the optical behavior of the model compounds and their potential use as antenna moieties in bichromophoric systems, the photophysical properties of all samples were studied using ultraviolet–visible absorption and steady-state fluorescence spectroscopy in methanol solutions. For the case of the acridinediones, the fluorescence spectra were found to exhibit the typical emission profile of the locally excited state, whereas, contrary to previous published experimental results, reliable fluorescence emission spectra for the xanthenes derivatives could not be obtained. On the other hand, the poor quantum yields of the synthesized decahydroacridine-1,8-diones were explained based on the benzene-like substitution effect, which favors the intersystem crossing relaxation mechanism.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Free azoxy radicals from benzoquinolines

Conclusions The 5,6- and 7,8-benzo derivatives of 4-methyl-2-spirocyclohexyl-3,4 3,2-tetrahydrofurano-1,2,3,4-tetrahydroquinoline and their paramagnetic N-oxides were synthesized. A study was made of the paramagnetic absorption spectra of the free radicals, which are bezoquinoline derivatives.     

E,E-1,4-二[2′,2″-(苯并噁唑基乙烯基)]苯及其衍生物的合成和光性能研究

合成了E,E-1,4-二[2′,2″-(苯并(口恶)唑基乙烯基)]苯及衍生物共14种,测定了它们的熔点、红外光谱、核磁共振氢谱、紫外吸收光谱和荧光发射光谱、荧光量子产率及激光性能。     

Hemicyanines from 3-arylbenzo [f] quinolinium salts and their spectral-luminescence properties

1-(-Anilinovinyl)-3-arylbenzo[f]quinolinium methiodides were synthesized by the condensation of 1,4-dimethyl-3-arylbenzo[f]quinolinium salts with ethyl orthoformate and aniline or by fusion with N,N-diphenylformamidine. The IR spectra, the absorption spectra in the visible region, and the fluorescence of the dyes in the crystalline state were examined. The introduction of substituents in the 3-phenyl ring of benzo[f]quinoline gives rise to a bathochromic shift of the fluorescence band.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 969–971, July, 1980.     

Stilbene-cored poly(glutamate) dendrimers

A new class of photoresponsive poly(glutamate) dendrimers based on a stilbene core unit was successfully synthesized. The core stilbene was used to probe the polarity inside the dendrimer based on changes in the absorption and fluorescence spectra under various solvent conditions. Upon acidification of a solution of one of the dendrimers, wG1, the absorption band decreased with red-shift and the fluorescence band decreased with blue-shift, indicating that the groups at dendrimer periphery were protonated, resulting in shrinking of the dendrimer via hydrophobic interactions, and the inside of the dendrimer became more hydrophobic than under neutral pH conditions. In addition, the core stilbene unit underwent photoisomerization to give the cis-isomer with concomitant structural change in the poly(glutamate) dendrimer.     

Spectral luminescence properties of 1- and 2-alkyl(cycloalkyl) derivatives of benzo[f]quinoline

The absorption and fluorescence spectra of alcohol solutions of 3-aryl-substituted benzo[f]-quinolines were investigated, and the fluorescence quantum yields were measured. It was established that the indicated compounds have intense absorption in the UV region and fluorescence at 350–450 nm. The fluorescence quantum yields range from 5 to 70%, depending on the substituents. The introduction of aromatic substituents in the 1 and 3 positions of benzo-[f]quinoline ring raises the fluorescence quantum yields. A methyl group in the 2 position of the molecule leads to a decrease in the fluorescence quantum yield. Benzo[f]quinoline derivatives that contain a cyclopentene ring in the 1 and 2 positions fluoresce intensely (=40–60%), while cyclohexene and cycloheptene condensed in the same positions cause a decrease in the fluorescence yield to 7–13%; this is associated with the three-dimensional structure of these molecules.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1237–1240, September, 1977.     

Synthesis and properties of coumarin-derived organogelators

A new family of coumarin derivatives containing amide group with different alkyl chain lengths was synthesized and their properties as organogelators were evaluated. It was found that the organogelation abilities were not obviously affected by the alkyl spacer length of amide group. Helical morphologies formed either in nonpolar or high polar solvents by most of the gelators. Occurrence of reversible and stereoselective photodimerization of the gel formed by 4-(7′-coumarinoxy)-N-octadecylbutanamide (3a) in cyclohexane was confirmed by ¹H NMR, UV absorption, and fluorescence spectra. The photoreaction of the gel proceeded without any dissolution, but the drastic microscopic changes of gel morphologies accompanied with the irradiation were identified using SEM and AFM investigations.     

Synthesis and spectral-luminescence properties of 2,5-diaryloxazoles that contain a difluoromethylsulfonyl group

A number of 2-(4-difluoromethylsulfonylphenyl)-5-aryloxazoles were synthesized by condensation of 4-difluoromethylsulfonylbenzoyl chloride with -aminomethyl aryl ketones and subsequent cyclodehydration of the resulting amides in sulfuric acid. The spectral-luminescence properties of these products were investigated. The introduction of a difluoromethylsulfonyl group in the 2-phenyl ring of 2,5-diphenyloxazole leads to significant bathochromic and bathofluoric effects and an increase in the quantum yields and photostabilities of the compounds obtained. Complication of the structure of the 5-phenyl ring is accompanied by a further long-wave shift of the absorption and fluorescence spectra without substantial changes in the fluorescence quantum yields. A positive solvatochromism effect is displayed distinctly in the fluorescence spectra of the compounds obtained on passing to polar solvents; this effect increases markedly as the polarity of the solvent increases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1042–1046, August, 1982.     

X-ray spectral study of a material containing BN nanostructures

The multicomponent substance obtained by laser evaporation of the BN target under nitrogen was studied by X-ray fluorescence and X-ray absorption spectroscopy. The BK _α spectra of the substance and boroncontaining compounds rh-BN, B₂O₃, and α-B were measured on a laboratory instrument using an ethyleneglycol distearate crystal as an analytical element; X-ray absorption spectra near the boron and nitrogen K edge were recorded on a BESSY synchrotron radiation station. The contents of the components in the synthesized substance were evaluated by decomposing the BK _α spectrum into the spectra of the test boron-containing compounds. A comparison of the X-ray absorption spectra near the NK edge of the substance and rh-BN revealed that BN nanostructures obtained by laser evaporation were defective.     

2,2'-二苯并噁唑衍生物的合成和光性能研究

合成了16种2,2-二苯并(口恶)唑衍生物,测定了化合物的熔点、红外光谱、紫外吸收光谱、荧光发射光谱以及荧光量子产率,与1,4-二(苯并(口恶)唑1′,3′-基-2′)苯和1,4-二(苯并(口恶)唑-1′,3′-基-2′)乙烯衍生物进行了比较,讨论了它们之间光谱特性的差异.     

Synthesis and spectral-luminescence properties of hetarylethylene derivatives of 2,5-diphenyloxazole and 2,5-diphenyl-1,3,4-oxadiazole

A number of new organic luminophores was synthesized by PO olefination from 2- (4-bromomethylphenyl)-5-phenyloxazole and -1,3,4-oxadiazole and various heterocyclic aldehydes that contain a furan ring. The absorption and fluorescence spectra of the products in toluene, as well as their scintillation characteristics, were measured. The effect of the electronic nature of the substituents on the spectral-luminescence properties of the luminophores is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 617–621, May, 1982.     

Synthesis and fluorescence properties of 7-hydroxy-3-(2-pyridyl)coumarin derivatives

Three coumarin derivatives, 7-hydroxy-3-(2-pyridyl)coumarin (HPC), 7-(4-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)benzyloxy)-3-(2-pyridyl)coumarin (Ox-PC), and 7-(4-(9H-carbazol-9-yl)butoxy)-3-(2-pyridyl)coumarin (Cz-PC), were synthesized and characterized by elemental analysis, ¹H NMR, FT-IR, and UV?Cvis absorption spectra. The fluorescence behaviors of the compounds in methanol solutions and solid states were investigated. HPC exhibits weak green emission, whereas Cz-PC and Ox-PC show strong blue emissions in dilute solutions.     

Synthesis and absorption spectra of thienylphenylpropenol derivatives

Fourteen thienylphenylpropenol derivatives containing substituents of varying electronic nature were synthesized. IR and NMR spectroscopy established that the , -unsaturated alcohols obtained belong to the trans series. The electronic and PMR spectra of the alcohols in neutral and acidic solutions were studied. A correlation was found between the chemical shifts of the proton of the alcohol hydroxyl group and the shifts of the wave numbers of the long-wave absorption maxima, and the Hammett constants.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 12, pp. 1605–1608, December, 1970.     

Polymer Fluoride Sensors Synthesized by RAFT Polymerization

A series of polymer chemosensors containing naphthalimide signal moiety and imide recognition moiety for the selective detection of fluoride ions (F⁻) were synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization. The polymer chemosensors display obvious absorption and fluorescence variations upon the addition of F⁻, which can be observed by both naked eyes and optical responses. The polymers showed higher fluorescence enhancement than its monomer, and the polymers with higher molecular weight have higher sensitivity than those with lower molecular weight. Other halide anions are found to hardly induce any variation of either the absorption or fluorescence spectra.

     

A novel chromatism switcher with double receptors selectively for Ag in neutral aqueous solution: 4,5-diaminoalkeneamino-N-alkyl-l,8-naphthalimides

Two novel fluorosensors of 4,5-disubstituted-N-alkyl-l,8-naphthalimide derivatives (H1, H2, H3) with double ethylenediamino receptors, double propylenediamino receptors, or one methylpiperazine receptor were synthesized, respectively. Their fluorescence and absorption in the presence or absence of nine metal ions were studied. In the presence of Ag⁺, H1's absorption moved to long wavelength with color change from yellow-green to red, its quenching and red shift in fluorescence were also remarkable. Similarly, H1's fluorescence was also strongly quenched in the presence of Cu²⁺. In addition, H1 and H2 show high pH sensitively. There was 139-folds fluorescence enhancement for H1, 22-folds for H2, and 4-folds for H3 when pH was changed from 8 to 3, respectively.     

Synthesis and Photophysical Properties of Alkoxysilyl Derivatives of Dibenzoylmethanatoboron Difluoride

Alkoxysilyl derivatives of dibenzoylmethanatoboron difluoride (DBMBF₂) are synthesized by the hydrosilylation reaction of the corresponding O‐allyl derivatives of DBMBF₂ with triethoxysilane. The photophysical properties of the synthesized O‐allyl and alkoxysilyl derivatives are investigated. It is found that the absorption and fluorescence spectra of the DBMBF₂ derivatives essentially depend on the position of the O‐allyl or O‐propyl alkoxysilyl substituent. The highest fluorescence quantum yield is obtained for the para‐position, whereas the substitution at the meta‐position gives the largest bathochromic shift in the fluorescence spectrum. Density functional theory calculations of the structures and time‐dependent density functional theory calculations of the gas‐phase excitation and emission energies of alkoxysilyl derivatives are performed at the PBE0/SVP level of theory. Some spectral features of para‐, ortho‐, and meta‐substituted derivatives can be adequately explained by the overlapping of two absorption bands.     

Microwave-assisted solvent-free catalyzed synthesis and luminescence properties of 1,2,4,5-tetrasubstituted imidazoles bearing a 4-aminophenyl substituent

A solvent-free microwave-assisted four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles bearing a 4-aminophenyl substituent was studied by condensation of p-phenylenediamine, aryl diketone, benzaldehyde derivatives and ammonium acetate in the presence of solid support silica gel and catalyst Keggin-H₃[PW₁₂O₄₀]. The effects of four components molar ratio along with catalyst loading, irradiation time on the yields were investigated. Also, the structures of synthesized compounds were characterized by FT-IR, HRMS, ¹H NMR and ¹³C NMR spectroscopy. Furthermore, their ultraviolet–visible maximum absorption, liquid fluorescence emission maximum and quantum yields were, respectively, measured in 0.05 M H₂SO₄ aqueous solution and in dichloromethane. Simultaneously, solid fluorescence spectra were determined in the powder state. The relationships between the optical behavior and the polarity of the solvents for some compounds were assessed. The results showed that the fluorescence quantum efficiency was increased by introducing amino phenyl in comparison with benzyl on 1-position of trisubstitued imidazoles. The compounds synthesized were sensitive to the polarity of the solvents.     

Fluorescence of 3,5-diethoxycarbonyl-1,4-dihydropyridine derivatives and their anions

The fluorescence spectra of a group of 3,5-diethoxycarbonyl-1,4-dihydropyridine (1,4-DHP) derivatives were investigated. The introduction of electron-acceptor N-substituents and 2,6-methyl groups decreases Q markedly. The fluorescence spectra of 1,4-DHP anions are shifted bathofluorically, and the Q values are higher than for the corresponding 1,4-DHP. The fluorescence spectra have large Stokesian shifts, which are decreased for 1,4-DHP anions. A good correlation exists between the _max values of the fluorescence bands of 1,4-DHP anions and the Hammett _p ⁺ constants of the 4-R-aryl substituents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 67–70, January, 1988.