and water was investigated by cw-e.s.r. spectroscopy. The products tert-butylperoxyl, methyl and sulfur-centered free radicals were identified. The tert-butoxyl free radical is involved in the primary process as shown by time-resolved e.s.r. technique. On the basis of directly identified radical species, a mechanism for the photochemically induced reactions of tert-butyl hydroperoxide in DMSO is proposed. At concentrations below 0.8 mol · l−1 the radical formation from tert-butyl hydroperoxide proceeds by cleavage of the O O bond rather than by hydrogen abstraction. 相似文献
A new diaroyl chloride monomer, 5-(4-benzoyl-2,3,5,6-tetrafluorophenoxy)isophthaloyl dichloride (BTFPIPC), was prepared in a three-step synthesis. Six novel aromatic polyamides containing 4-benzoyl-2,3,5,6-tetrafluorophenoxy pendant groups were synthesized by low temperature polycondensation of BTFPIPC with six aromatic diamines in N,N-dimethylacetamide (DMAc). All these new polymers are amorphous and readily soluble in various dipolar solvents such as DMAc, N-methyl-2-pyrrolidinone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) at room temperature. These polymers showed glass transition temperatures between 212 and 243 °C and 5% weight loss temperatures ranging from 439 °C to 456 °C. These polyamides could be cast into transparent, flexible and strong films from DMAc solution with tensile strengths of 73.5–85.4 MPa, tensile moduli of 2.06–2.72 GPa, and elongations at break of 6.4–9.3%. These new polyamide films exhibited low dielectric constants of 3.26–3.57 (1 MHz), lower water uptakes in the range of 1.27–2.28%, and excellent transparency with an ultraviolet-visible absorption cut-off wavelength in the 326–373 nm range. Primary characterization of these new polyamides shows that they might serve as new candidates for processable high-performance polymeric materials. 相似文献
The novel porphyrin monomer 5-(4-acryloyloxylphenyl)-10,15,20-tris(4-carboxyphenyl)porphyrinate zinc(II) (ZnAOTCPP) and its corresponding sodium salt (ZnAOTCPP-Na) were synthesized. The latter compound exhibited a new band in excitation spectra due to formation of porphyrin aggregates in water, which were derived from its surface-activity when the concentration was higher than its critical association concentration (CAC). The porphyrins were copolymerized with acrylamide (AM) to prepare water-soluble copolymers with random and micro-blocky structures, which all displayed very new absorption and fluorescence emission bands in the long wavelength region compared with the porphyrin monomer. Furthermore, the micro-blocky copolymer exhibited an additional new absorption band at even longer wavelength region compared with the random copolymer. The experimental results and analysis showed that the porphyrin units in the random copolymer chains self-assembled to form porphyrin association complexes by hydrophobic association and π-π stacking interactions, and covalent restrictions of polymer chains in the micro-blocky copolymer. 相似文献
Novel 5-benzazolyl-10,15,20-triphenylporphyrins and β,meso-benzoxazole-linked diporphyrins were synthesized through La(OTf)3 catalyzed reaction of newly prepared 5-(3,4-diaminophenyl)-10,15,20-triphenylporphyrin or 5-(3-amino-4-hydroxyphenyl)-10,15,20-triphenylporphyrin with aromatic aldehydes in 1,2-dichlorobenzene. On metalation with zinc acetate, freebase β,meso-benzoxazole-linked diporphyrin was successfully converted to the Zn-Zn diporphyrin complex in good yield. The synthesized porphyrin analogues were characterized using electronic absorption, IR and 1H NMR spectroscopy in addition to mass and elemental analyses. The fluorescence studies of 5-benzazolyl-10,15,20-triphenylporphyrins showed efficient intramolecular energy transfer from the pyrene and fluorene subunits to the porphyrin core. In addition, the fluorescence quenching observed in β,meso-benzoxazolyl-bridged porphyrin dyads was attributed to the possible nonplanarity of a component of the diporphyrins. The freebase-Ni diporphyrin complex underwent strong emission quenching in comparison to that of freebase diporphyrin and dizinc diporphyrin analogues. 相似文献
The one‐pot synthesis of substituted 2‐arylquinazoline derivatives and tetracylic isoindolo[1,2‐a]quinazoline via cyanation followed by rearrangement of ortho‐substituted 2‐halo‐N‐arylbenzamides is described. Using dimethyl sulfoxide (DMSO) as the solvent, the cleavage of the tetracyclic isoindole fused quinazoline leads to the formation of 2‐arylquinazoline derivatives. When 1,4‐dioxane is used as the solvent, tetracyclic isoindole fused quinazolines are produced in good yield. A wide range of products, including 2‐phenylquinazolin‐4‐amine, 4‐methyl‐2‐phenylquinazoline and long‐chain 2‐phenyl‐4‐styrylquinazoline derivatives were produced in moderate to good yields using DMSO as the solvent. However, various tetracyclic isoindole fused quinazoline derivatives were obtained in good yields when 1,4‐dioxane was used as the solvent.
A series of benzo- and naphthothiazolediones have been synthesized by the reactions of N-substituted thioureas with π-deficient quinones. The products were obtained by the reaction of N-aroylphenylthioureas with 2,3,5,6-tetracholoro-1,4-benzoquinone, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 2,3-dichloro-1,4-naphthoquinone. 相似文献
Synthesis and spectral evaluation of new zinc and copper unsymmetrical mesoporphyrinic complexes are reported. Zn(II)-5-(4-acetoxy-3-methoxyphenyl)-10,15,20- tris-(4-carboxymethylphenyl)porphyrin, Zn(II)-5-[(3,4-methylenedioxy)phenyl]-10,15,20- tris-(4-carboxymethylphenyl)porphyrin, Cu(II)-5-(4-acetoxy-3-methoxyphenyl)-10,15,20- tris-(4-carboxymethylphenyl)porphyrin and Cu(II)-5-[(3,4-methylenedioxy)phenyl]-10,15,20- tris-(4-carboxymethylphenyl)porphyrin were synthesized using microwave-assisted synthesis. The complexes were characterized by elemental analysis, FT-IR, UV-Vis, EPR and NMR spectroscopy, which fully confirmed their structure. The spectral absorption properties of the porphyrinic complexes were studied in solvents with different polarities. Fluorescence emission and singlet oxygen formation quantum yields were evaluated for the compounds under study, revealing high yields for the zinc derivatives. The copper complexes are not emissive and only display residual capacity for singlet oxygen formation. 相似文献
The condensation of phenyl-, p-tolyl-, p-anisyl-, and p-chlorophenyl isopropyl ketones with dimethyl methylsuccinate in the presence of potassium t-butoxide, gave the crystalline (E)-4-aryl-3-methoxycarbonyl-2-methyl-4-isopropyl-but-3-enoic acids
1 i.e., Ar and COOCH3 in trans-position. The nomenclature of cis/trans isomers used herein follows the IUPAC 1968 Tentative Rules, Section E, Fundamental Stereochemistry, J. org. Chemistry 35 , 2849 (1970). See also: J. E. BLACKWOOD , C. L. GLADYS , K. L. LOENING , A. E. PETRARCA and J. E. RUSH , J. Amer. chem. Soc. 90 , 510 (1968); Introduction to Subject Index of Chem. Abstr. 66 (1963).
1 as major products. These esters resisted oxidation, and the position of the double bond was indicated by their infrared absorption, as well as that of some derived products. Their configuration followed from their conversion to the 4-acetoxy-2-naphthoates 2 . The condensation also gave oily half-ester fractions which proved to contain small amounts of the (Z)-isomers 5 by their conversion (in low yields) to the oxoindenyl acids 6 . 相似文献
An expedient cleavage of the C S bond of dimethyl sulfoxide (DMSO) has been developed for the preparation of substituted pyridines from ketones. In this transformation, the co‐product formic acid was formed from ammonium formate, which acted as an important catalyst for the reaction. Notably, this transformation exhibited a broad substrate scope towards a wide variety of different ketones to give the corresponding substituted pyridines in high yields. Mechanistic studies suggested that dimethyl sulfoxide delivered a methylene fragment, which was subsequently captured in situ to give a pyridine.
The reaction of N-phenyl-1,4-benzoquinoneimine (I)
1 Decoding of abbreviations see p. 103/104.
and 4-hydroxydiphenylamine (II) with the carbon centred 1-cyano-1-methylethyl radical (R·) was studied in connection with an investigation of the action mechanism of industrial antidegradants, such as N-phenyl-N′-sec-alkyl-1,4-phenylenediamines. The mixture of I and II reacts very readily with R·, giving rise to III , VI , and VIII . I alone reacts much slowlier, and the reaction mixture contains more products. IV and VII were identified along with III . Under the conditions used, II alone does not react at all. IV exists in two isomeric forms, syn and anti. VIII is very labile; XI was isolated from its transformation products. Reduction of IV gives V , which is labile, similarly to VIII . 相似文献
New electroluminescent polymers with various phenyl groups, poly[2-dimethyl(octyl)silyl-5-(4-(dimethyl(octyl)silyl)phenyl)-1,4-phenylenevinylene] (P1), poly[2,5-bis(4-(dimethyl(octyl)silyl)phenyl)-1,4-phenylenevinylene] (P2), poly[2,5-bis(9,9-dihexylfluorenyl)-1,4-phenylenevinylene] (P3), and poly[2,5-bis(4-(4-(2-etylhexyloxy)phenyl)phenyl)-1,4-phenylenevinylene] (P4), have been synthesized by the Gilch polymerization. The maximum absorption peaks of P1-P4 appeared at 388-423 nm in THF solution, and are red-shifted to 404-425 nm in solid thin film. The photoluminescence (PL) emission spectra of P1-P4 show a maximum peak at 482-503 nm in THF solution and at 521-549 nm as the solid film state. The emission spectra in the solid film state are more red-shifted over 40 nm, and the full width at half maximum (fwhm) was 30 nm greater than the solution conditions. The polymer light-emitting diodes (PLEDs) with the configuration of ITO/PEDOT/polymer/Al emitted light with maximum peaks at around 517-546 nm. The various phenyl substituents, with intermolecular interactions in the solid film state, can introduce the color tuning and device performance enhancement of the conjugated polymer as an emissive layer in PLED. 相似文献
(TGMBT) using various amines like 4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylsulfone (DDS) and diethylene triamine (DETA) as curing agents. The fabricated laminates were evaluated for their mechanical and dielectrical properties and chemical resistance. The composites prepared using an epoxy fortifier (20 phr) showed significant improvement in the mechanical properties. 相似文献
The novel water soluble antenna polyelectrolyte: poly[sodium styrene sulfonate-co-(4-acryolyloxyphenyl)-10,15,20-tritolylporphyrin] (PSSS-Po) was synthesised, and its photophysical and photochemical properties were studied. Solubilisation of the various molecular probes such as pyrene or perylene in aqueous solution of the PSSS-Po proved that the polymer chain adopts the compact conformation. The interior of the polymer pseudomicelle is significantly less polar than water. The effective quenching of polymeric porphyrin fluorescence by sulfopropyl viologen (SPV) can be explained considering the possibility of electron transfer from the singlet-excited state of Po to SPV. This has been supported by measuring an absorption spectrum for PSSS-Po/SPV system after selective irradiation of Po chromophores. The formation of the new absorption bands characteristic for SPV− radical anion indicated that the charge separation was achieved in that system. 相似文献
The condensation of pyrrolyl-2-aldehyde or 1-methyl-pyrrolyl-2-aldehyde with dimethyl succinate, using sodium hydride as condensing agent, gave predominantly the halfesters 1a and 1c respectively. Their structure and (E)-configuration
1 i. e., pyrrol ring and COOCH3 group are in trans position. This nomenclature follows the IUPAC 1968 Tentative Rules, Section E, Fundamental Stereochemistry, J. org. Chemistry 35 , 2849 (1970).
were confirmed by their cyclisation to the corresponding indole derivatives 2a–h . 相似文献