Anomalous disproportionation of 9-benzoylanthracene and 9-anthryl styryl ketone

9-Benzoylanthracene and 9-anthryl styryl ketone disproportionate to anthracene and the corresponding 9,10-diacylanthracene when warmed in carbon disulphide or nitrobenzene with an excess of aluminium chloride. The reactions are co-catalysed by hydrogen chloride. Comparison is made with other 9-anthryl ketones and with 1-naphthyl styryl ketone, which undergo different reactions under similar conditions. The results are interpreted in terms of steric requirements.     

Polyphosphoic acid-catalyzed cyclisations of aryl styryl ketones

Reaction of a number of aryl styryl ketones with polyphosphoric acid has been investigated and, with the exception of 9-anthryl styryl ketone, each undergoes smooth cyclisation to give an isomeric 5-membered ring ketone. The polyphosphoric acid- and aluminium chloride-catalysed cyclisations of 1-naphthyl styryl ketone, which give 3-phenyl-2,3-dihydrobenz(e)inden-1-one and phenalen-1-one respectively, are discussed and a general interpretation of the cyclisation modes of 1-naphthyl substituted ketones and carboxylic acids in terms of the HSAB theory is offered.     

Synthesis and optical behaviors of 2-(9-phenanthrenyl)-, 2-(9-anthryl)-, and 2-(1-pyrenyl)-1-alkylimidazole homologues

Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λ_amax, fluorescence emission maximum λ_em, Stokes shifts and fluorescence quantum yields (Φ_F) in ethyl acetate were determined; their fluorescent lifetimes (T₁ and T₂) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed.     

Kinetic study of photophysical and photochemical processes in α,ω-(bis-9-anthryl)-n-alkanes (ethane to decane) at room temperature

Fluorescence and photocyclomerization quantum-yield measurements and a transient kinetic analysis were performed for a series of α,ω-(bis-9-anthryl)-n-alkanes (A-C₂-A to A-C₁₀-A and A-mXy-A) in methylcyclohexane and ethanol. Of note is an irregular periodicity of intramolecular excimer fluorescence yields and the rate parameters for excimer collapse to photocyclomer.     

Crown-ether styryl dyes

The surface enhanced Raman scattering (SERS) spectra of styryl dyes containing a crown-ether group and a heteroaromatic residue with sulfoalkyl (1a) or alkyl (1b)N-substituent and of their complexes with Mg²⁺ cations were recorded in the 10^–4–10^–8 mol L^–1 concentration range. A model for the interaction of compoundsla,b with a silver surface during their adsorption on an electrochemically treated electrode was suggested. Fastcis-trans relaxation of the adsorbed molecules1a,b and complexes (1a,b)Mg²⁺ was found. It was shown that at [1a] = 10^–5 mol L^–1 and moderate molar ratios (C _Mg/[1a] = 3/1 to 9/1) in acetonitrile solutions, (trans-1a)Mg²⁺ complexes are joined into head-to-tail type dimers. An excess of Mg²⁺ cations (C_Mg/[1a] > 100) leads to dissociation of the dimers yielding (trans-1a)(Mg²⁺)₂ complexes. The formation of dimers from complexes (trans-1a)Mg²⁺ is accompanied by a substantial distortion of the planar structure oftrans-1a. This may be an important factor influencing the efficiency of photocycloaddition involving dimers of (trans-1a)Mg²⁺.For part 15, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2429–2436, December, 1995.The work was carried out with financial support of the Russian Foundation for Basic Research (Project No. 94-03-08760) and, to some extent, of INTAS (Grant No. 93-1829) and of the International Science Foundation (Grant No. MHAOOO).     

Electronic spectroscopy of [2n](9,10)anthracenophanes and the “excimer” conformation of di(9-anthryl)methane. Effect of orbital overlap on the 1La and 1Lb states of anthracene

A polarization analysis of the absorption spectra of a single related conformaion of each of the [2.n] (9,10)anthracenophanes (n = 2–5) is given States derived from ¹ L_a and ¹Li_b have been identified Analogous results for the “excimer” or photorcactive conformation of di(9-anthryl)methane have been obtained.     

Crown ether styryl dyes

Novel styryl dyes (trans-2a,b) containing a 15-crown-5 ether moiety and anN-sulfobenzyl spacer were synthesized. The reactions oftrans-2a,b with Mg(ClO₄)₂ in MeCN afford dimeric complexes. During photolysis of the lattertrans-cis isomerization to give anion-“capped” complexes (cis-2a,b)·Mg²⁺ and stereospecific [2+2] autocycloaddition to yield cyclobutane derivative occur in parallel The ratio of the two transformation pathways of dyes2a,b depends on the spacer type. To interpret the experimental data, the molecular-mechanics and semiempirical quantum-chemical calculations were performed.     

Characterization of the functionalization reaction product of poly(styryl)lithium with ethylene oxide

The functionalization reaction of poly(styryl)lithiums (M_n = 1.3–9.9 × 10³) with ethylene oxide in benzene proceeds quantitatively ( > 99%) to produce the corresponding hydroxyethylated polymer as determined by vapor phase osmometry, size exclusion chromatography, end-group titration, thin layer chromatography, and ¹H- and ¹³C-NMR spectroscopy. ¹³C-NMR spectral analysis of the functionalized polystyrene with M_n = 1.3 × 10³ was consistent with addition of only one ethylene oxide unit to poly(styryl)lithium, i.e., no evidence for ethylene oxide oligomerization was observed.     

Supramolecular assembler based on cucurbit[8]uril: Photodimerization of a styryl dye in water

Photolysis of aqueous solutions of styryl dye 1 in the presence of cucurbit[8]uril (CB[8]) has been studied by optical spectroscopic methods for the molar ratios n = c _CB[8]/c ₁ in the range of 0 ≤ n ≤ 6. It has been found that the inclusion complexes (1)₂@CB[8] dominate in the solution at n ≤ 0.5, whereas the complexes 1@CB[8] dominate at n ≥ 1. The stability constants have been determined for the 1: 1 (log K ₁ = 6.2 (L mol^?1)) and 2: 1 (log β = 11.9 (L² mol^?2)) complexes. The fluorescence decay kinetics of dye 1 in the presence of CB[8] is two-exponential, with the average lifetime increasing substantially at n ≥ 1. It has been shown that the system can operate in the cyclic mode as an assembler (or supramolecular catalyst) in the photodimerization reaction of dye 1 to form cyclobutane derivative 2. The stability constant of the complex 2@CB[8] (log K ₃ = 5.9 (L mol^?1)) and the quantum yield of cycloaddition (? ≈ 0.07 at n ≈ 0.5) have been determined.     

Redox properties of N2S2-type nickel complexes with aromatic ligands. Crystal structure of [1,2-C6H4(SMe)NH2]2Ni2+(MeCN)2·2ClO4–

The redox properties of six chelate N₂S₂-type Ni(ii) complexes containing two aromatic NS or one N₂S₂ ligands, such as 2-aminothiophenol, 2-aminothiophenolate anion, 2-amidothiophenolate dianion, 2-amidothioanisole, 2,2"-diaminodiphenyl disulfide dianion, and 8-quinolinethiolate anion, were studied by cyclic voltammetry at a glassy-carbon electrode in DMF. Some free ligands were also studied for comparison. A new Ni^II complex with the 2,2"-diamidodiphenyl disulfide dianion was synthesized. The crystal and molecular structures including the square planar Ni(N₂S₂) center with two MeCN molecules as additional axial ligands were established for the Ni^II complex with 2-aminothioanisole [1,2-C₆H₄(SMe)NH₂]₂Ni²⁺(MeCN)₂·2ClO₄ ^– using X-ray diffraction. The most part of the studied compounds are irreversibly oxidized and reduced; however, bis(2-amidothiophenolato)nickel(iv) and bis(8-quinolinethiolato)nickel(ii) show a quasi-reversible behavior in the reduction region. The electrochemically generated anionic form of the 8-thioquinoline complex is rapidly alkylated in the presence of BuⁿBr or BuⁿI to form, probably, the corresponding butylnickel(iii) complex.     

Poly(imino imino ether ether ketone ketone) as novel soluble heat-resistant polymer

In this paper, we introduce a novel high-performance polymer, poly(imino imino ether ether ketone ketone), which has been synthesized by the palladium-catalyzed C-N cross coupling reaction of 1,4-bis-(4-bromobenzoyl) benzene and 1,3-bis-(4-aminophenoxy) benzene. The structure of the polymer is characterized by means of ¹H NMR spectroscopy and elemental analysis, and the results show a good agreement with the proposed structure. Compared with traditional poly(ether ether ketone)s, the solubility of the synthesized polymer in common organic solvents was higher; it also exhibited high glass transition temperature (T _g = 176°C) and good thermal stability with high decomposition temperature (T ₅ = 400°C).     

Electrodimerization of the pyridiniumcarboxylic acids homarine and trigonelline

Homarine (1-methyl-2-carboxypyridinium ion) and trigonelline (1-methyl-3-carboxy-pyridinium ion) are reduced at mercury electrodes in alkaline solutions by a one-electron transfer to the pyridinium ring. Analysis of polarographic wave shapes using deviation-pattern recognition, peak widths of cyclic voltammograms, analysis of the products of bulk electrolyses and dependences of E_1/2 and E_p on scan rate, pH and concentration indicated that these reductions proceed by an EC² mechanism, where the second-order chemical reaction is a homogeneous dimerization. The zwitterionic form of the pyridiniumcarboxylic acid, which predominates in alkaline solutions, undergoes reduction to form a pyridinyl anion radical. Two radicals then couple to yield a dimer dianion which is subject to protonation. The dimer can be oxidized at mercury electrodes.     

Crown ether styryl dyes

New crown ether-containing styryl dyes of the benzothiazole series containing an aza-15-crown-5-ether moiety were synthesized. Thetrans-cis-photoisomerization of these dyes and their analogs was studied; the effect of metal cations on the kinetics of darkcis-trans-isomerization was elucidated. The stability constants of the complexes of thecis-isomers of these dyes with Ca(ClO₄)₂ were estimated. The dramatic increase (by more than three orders of magnitude) in the stability of the complexes on passing from a cationic dye to a betaine was attributed to the formation of an intramolecular bond in thecis-complexes between the sulfo group of theN-substituent and the metal cation located in the cavity of the azacrown-ether moiety.     

Synthesis and curing behavior of alkyl-substituted poly(aryl ether ketone)s having a crosslinkable styryl group at chain ends

Crosslinkable alkyl-substituted poly(aryl ether ketone)s (PEKs) bearing a styryl group at both chain ends were synthesized by nucleophilic substitution reaction of 1,1′-(p-phenyl-enedioxy)bis[2-methyl-4-(4-fluorobenzoyl)benzene] with an excess aromatic diol in the presence of a base, followed by the reaction of the terminal phenol group with chloromethylstyrene. The aromatic diols used in this study were hydroquinone and resorcinol. The molecular weight of the polymer determined by GPC and ¹H NMR agreed with each other and close to the theoretical value calculated from the feed ratio. The polymer was soluble in N,N-dimethylacetamide and tetrahydrofuran, but insoluble in acetone and methanol. From DSC analysis, the polymer was thermally crosslinked around 220°C. The addition of dicumyl peroxide as a radical generator in the polymer decreased the curing temperature. The cured polymer showed high thermal stability up to 420°C under nitrogen. © 1997 John Wiley & Sons, Inc.     

Photoprocesses in <Emphasis Type="Italic">N</Emphasis>-ammonioalkyl derivatives of azacrown-containing styryl dyes and their complexes with metal perchlorates

Photophysical processes and photochemical reactions in the N-ammonioalkyl derivatives of the azacrown-containing styryl dyes and their complexes with lead and barium perchlorates in MeCN and CH₂Cl₂ were studied by ¹Н NMR spectroscopy, absorption spectroscopy, luminescence spectroscopy, laser kinetic spectroscopy, and quantum chemistry. Molecules of the styryl dyes and their complexes are able to undergo normal (fast) and delayed fluorescence and trans–cis-photoisomerization. The molecules in the triplet state participate in degradation processes of the electron excitation energy.     

Ruthenium-catalyzed reduction of racemic tricarbonyl(η-aryl ketone)chromium complexes using transfer hydrogenation: A simple alternative to the resolution of planar chiral organometallics

Racemic planar chiral (η⁶-aryl ketone)Cr(CO)₃ complexes (aryl ketone = 1-indanone, 1-tetralone, 4-chromanone and thiochroman-4-one) were prepared by refluxing the aryl ketone with Cr(CO)₆ in a 10:1 mixture of dibutyl ether and THF. The reductions of the organometallic ketones by transfer hydrogenation in 2-propanol containing KOH and the catalyst precursor, generated from [RuCl₂(η⁶-benzene)]₂ and (−)-ephedrine, resulted in optically active syn-(R,S)-(η⁶-aryl alcohol)Cr(CO)₃ and (R)-(η⁶-aryl ketone)Cr(CO)₃ compounds in 31-97% ee. Reduction of racemic (η⁶-thiochroman-4-one)Cr(CO)₃ with the catalyst precursor generated from (+)-norephedrine, instead of (−)-ephedrine, inverted the configuration of the products obtained. Syn-(S,R)-(η⁶-thiochroman-4-ol)Cr(CO)₃ and (S)-(η⁶-thiochroman-4-one)-Cr(CO)₃ were isolated in 49% and >95% ee, respectively. The free aryl ketones were reduced using the same conditions as their respective chromium complexes, giving aryl alcohols in high ee (>95%). Reactions of non-rigid acetophenone, propriophenone and their tricarbonylchromium complexes resulted in moderate to low ee.     

Analytical study of the phenyl-2-pyridyl ketone azine-palladium system. Photometric determination of palladium

Phenyl-2-pyridyl ketone azine reacts with palladium(II) to produce a yellow 1:1 complex (λ_max = 425 nm, ? = 10.4 × 10³M^?1 cm^?1 in aqueous ethanolic solution) and a red-violet 3:1 complex (λ_max = 530?540 and 380?390 nm). The yellow complex in aqueous ethanolic solution has been used for the spectrophotometric determination of trace amounts of palladium. The method has been applied to the determination of palladium in some catalysts and one mineral.     

Crown-containing styryl dyes

Styryl dyes containing a crown ether group and a heteroaromatic moiety with a sulfoalkylN-substituent (1a,b) undergo photocyclodimerization in acetonitrile in the presence of Mg(ClO₄)₂ to give only the typeA isomer of cyclobutane derivative (2a,b). The photochemical regio- and stereoselectivity of the cycloaddition is explained by self-organization of thetrans-isomers of the styryl dyes upon complexation with the Mg²⁺ cations into dimers with a fixed mutual arrangement of multiple bonds.For part 7, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1449–1452, August, 1993.     

Structure‐controlled synthesis of novel soluble and thermally stable poly (aryl ether nitrile ether ketone ketone)/poly (aryl ether nitrile ether ketone biphenyl ketone) copolymers by electrophilic polycondensation

One new synthesis route was first designed to synthesize the biphenyl acid chloride (BPACl), and then a series of novel poly (aryl ether nitrile ether ketone ketone) (PENEKK)/poly (aryl ether nitrile ether ketone biphenyl ketone) (PENEKBK) copolymers with different controlled structure compositions were synthesized by electrophilic polycondensation and varying the molar ratio of BPACl to terephthaloyl chloride (TPC). The obtained PENEKK/PENEKBK copolymers were characterized by different physical and chemical techniques. The results showed, the copolymers with 10–50% molar contents of biphenyl moities exhibited good thermal properties with glass transition temperatures (T_gs) of 184–196°C, decomposition temperatures (T_ds) of 498–515°C, and good solubility in organic solvents (N‐Methyl‐2‐pyrrolidone (NMP), N,N‐dimethylformamide (DMF), and DMSO), indicating that they would have good potential for solvent processing. The thin films of the polymers had tensile strengths of 93.6–101.5 MPa, Young's moduli of 3.03–3.32 GPa, elongations at break of 9–14%, indicating they were strong materials. The densities of the obtained polymers were 1.31–1.40 g/cm^?3, which were far lower than those of some main inorganic materials (such as Fe, nearly 7.8 g/cm^?3), indicating that they would have possible potential for substituting some inorganic materials used as high temperature materials in some areas due to the merits of lightweight. Thus, the copolymers with 10–50% molar contents of biphenyl moities were promising polymer materials. Copyright © 2010 John Wiley & Sons, Ltd.     

Styryl coupling vs. styryl acetate formation in reactions of styryl tellurides with palladium(II) salts

In sharp contrast to the expected formation of a telluride-palladium complex, the treatment of either (E,E)- and (Z,Z)-distyryl tellurides (1 and 2) or (E)- and (Z)-styryl phenyl tellurides (5 and 6) with Li₂PdCl₄ in acetonitrile at 25°C results in the formation of stereoisomeric 1,4-diphenylbuta-1,3-dienes, whereas the treatment of 1 and 2 with Pd(OAc)₂ produces styryl acetates solely or mainly.