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 of spirocyclic benzo[f]quinoline derivatives by cascade heterocyclization of dimedone, 2-naphthylamine, and formaldehyde

The three-component condensation of dimedone, 2-naphthylamine, and formaldehyde in aliphatic alcohols under mild conditions gives in high yields the corresponding N-alkoxymethyl benzo[f]quinoline derivatives having a substituted 2-azaspiro[5.5]undecane fragment. The reaction involves formation of three new carbon-carbon bonds, two carbon-nitrogen bonds, and one carbon-oxygen bond, and the initial β-dicarbonyl system is conserved.     

Synthesis of 2-(2-Naphthyl)quinolines from Z-3-(2-Naphthyl)-3-chloro-2-propenal

By reaction of Z-3-(2-naphthyl)-3-chloro-2-propenal and aromatic amines 1-(2-naphthyl)-3-iminoaryl-1-propenylarylamines were prepared which at heating in the glacial acetic acid afforded the corresponding 2-(2-naphthyl)quinolines.     

On the conductance of order Markov chains

Let Q be a convex solid in ⁿ , partitioned into two volumes u and v by an area s. We show that s>min(u,v)/diam Q, and use this inequality to obtain the lower bound n ^-5/2 on the conductance of order Markov chains, which describe nearly uniform generators of linear extensions for posets of size n. We also discuss an application of the above results to the problem of sorting of posets.Computing Center of the USSR Academy of Sciences USSR     

Three-dimensional absolute and convective instabilities,and spatially amplifying waves in parallel shear flows

A formalism for absolute and convective instabilities in parallel shear flows is extended to the three-dimensional case. Assuming that the dispersion relation function is given byD(k, l, ), wherek andl are wave numbers, and is a frequency, the analytic criterion is formulated by which a point (k ₀,l ₀, ₀) with Im ₀>0 contributes to the absolute instability if and only if one of the two equivalent conditions is satisfied:

Synthesis of 2,4-substituted 5,6-benzoquinolines

By the catalytic condensation of azomethines with aliphatic-aromatic and heterocyclic ketones, derivatives of 5,6-benzoquinoline containing thiophene or pyridine rings as substituents have been synthesized.     

Synthesis and Properties of Copper,Mercury, and Silver (2-Naphthyl)acetylenides

(Z)-2-Naphthylacetylene was synthesized by the reaction of (Z)-3-(2-naphthyl)-3-chloropropenal (prepared from 2-acetylnaphthalene) with aqueous NaOH in dioxane. The reactions of 2-naphthylacetylene with CuCl, [Ag(NH₃)₂]NO₃, and K₂[HgI₄] gave copper, silver, and mercury 2-naphthylacetylenides, respectively. Silver naphthylacetylenide reacts with iodine to give the iodoethynyl derivative, which readily takes up bromine across the triple bond.     

Molecular structure and spectral properties of thionaphthalimides

The molecular structure and absorption spectra of monothio- and dithio-naphthalimides were compared to their naphthalimide analogues using AM1, PM3 and ZINDO/S semiempirical quantum chemical methods. The substitution of the 4R-naphthalimide oxygen atoms by sulphur atoms resulted in a red-shift of the absorption spectra by Δλ_max60-65 and 100-140 nm, respectively. The thionated naphthalimide derivatives do not show observable fluorescence due to intersystem crossing to the triplet -states localised at the CS groups. The -absorption bands of monothioimides are located at 525-580 nm (ε=60-80) and those for dithioimides at 535-560 nm (ε=140-390) and 628-686 nm (ε=34-68). None of these transitions are solvent sensitive. The -transitions of N-phenylthioimides have also a small contribution from -states due to a partial conjugation between CS group and π-electronic system of the N-phenyl ring. As a result, the bands of aromatic substituted N-phenylthioimides are red-shifted as compared to those of the aliphatic N-methyl-thioimides.     

Crystal structure and nontrivial magnetic properties of CuII binuclear complex based on 4-methyl-2,6-bis{[2-(4,6-dimethyl-pyrimidin-2-yl)hydrazono]methyl}phenol

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Spectroscopic Study of Azo- and Azoxycrowns Binding with Cations of Similar Ionic Radius

The complexation of 13- and 16-memberedazo- and azoxycrowns with metal cations of similarionic diameter (Na⁺ and Ca²⁺; and K⁺,Ba²⁺, Ag⁺ and Pb²⁺) was studied byuv/visible spectroscopic titration in acetonitrile andMeOH. In MeOH the 13-membered azo- and azoxycrowns 1 and 2 are weakly and non-selectively bound tohard cations of similar ionic diameter, but differentcharge (Na⁺ and Ca²⁺). At the same time thebinding to the soft cation Ag⁺ of larger sizethan the macrocycle cavity is considerably stronger.In contrast to solutions in acetonitrile no bindingwith the small Li⁺ cation was found.The 16-membered azocrowns 3 and 4 alsodiscriminate silver cation in MeOH withlog K = 3.65 ± 0.1 for both compounds.Unexpectedly low bindingwith the hard barium divalent cation of similar size(log K = 1.55 ± 0.4 and 1.95 ± 0.2, respectively)was found for these compounds. Similarly to13-membered compounds no binding with the smallLi⁺ cation was detected. A reverse order ofselectivity was observed for these crowns inacetonitrile with binding constant for association of3 with Ba²⁺ (log K 5.3) considerablyhigher than for other cations. The previously observedstrong binding with the smaller Li⁺ and Na⁺cations is confirmed.