Showing papers on "Benzophenone published in 2007"
TL;DR: In this paper, a benzophenone-diphenylamine co-crystal nucleates from a submerged eutectic and is used for grinding induced synthesis of such materials.
Abstract: A benzophenone–diphenylamine co-crystal nucleates from a submerged eutectic—is this a possible mechanism of grinding induced synthesis of such materials?
135 citations
TL;DR: The first organocatalytic enantioselective 1,6-addition of β-ketoesters and benzophenone imine to electron-poor δ-unsubstituted dienes using cinchona alkaloids under phase-transfer conditions is demonstrated in this paper.
Abstract: The first organocatalytic enantioselective 1,6-addition of β-ketoesters and benzophenone imine to electron-poor δ-unsubstituted dienes using cinchona alkaloids under phase-transfer conditions is demonstrated. The scope of the reaction for the β-ketoesters is outlined for reactions with different δ-unsubstituted dienes having ketones, esters, and sulfones as electron-withdrawing substituents giving the corresponding optically active products in good yields and enantioselectivities in the range of 90−99% ee. The 1,6-addition also proceeds with a number of cyclic β-ketoesters having different ring sizes, ring systems and substituents in high yields and enantioselectivities. The potential of this new organocatalytic 1,6-addition for β-ketoesters is demonstrated by a two-step synthesis of the bicyclo[3.2.1]octan-8-one structure, a bicyclic bridged skeleton occurring in a variety of natural compounds. Benzophenone imines also undergo the organocatalytic asymmetric 1,6-addition to the activated dienes in high yi...
119 citations
TL;DR: The synthesis of diarylmethanols via the reduction of a range of substituted benzophenone and benzoylpyridine derivatives with ketoreductase enzymes with KREDs has afforded chiral products with high yield and ee with good selectivity.
108 citations
TL;DR: A proposed degradation pathway of CV and CB, involving mainly the N-de-alkylation and oxidation reaction, is presented, and it is indicated that the N -de-methylated degradation of CV dye took place in a stepwise manner to yield N- de- methylated CV species.
Abstract: The methyl green (MG) dye dissolves into an alkaline solution when the pH value is too high (pH 9). The cationic MG dye molecules are converted into the colorless carbinol base (CB) and produce crystal violet (CV) dye and ethanol by hydroxide anion. Thirty-three intermediates of the process were separated, identified, and characterized by HPLC-ESI-MS technique in this study and their evolution during the photocatalytic reaction is presented. Moreover, the other intermediates formed in the photocatalytic degradation MG processes were separated and identified by HPLC-PDA technique. The results indicated that the N-de-methylated degradation of CV dye took place in a stepwise manner to yield N-de-methylated CV species, and the N-de-alkylated degradation of CB also took place in a stepwise manner to yield N-de-alkylated CB species generated during the processes. Moreover, the oxidative degradation of the CV dye (or CB) occurs to yield 4-(N,N-dimethylamino)phenol (DAP), 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino)benzophenone (DDBP) and their N-de-methylated products [or to yield 4-(N-ethyl-N,N-dimethyl)aminophenol (EDAP), DDBP, 4-(N-ethyl-N,N-dimethylamino)-4'-(N',N'-dimethylamino)benzophenone (EDDBP), DAP, and their N-de-alkylated products], which were found for the first time. A proposed degradation pathway of CV and CB is presented, involving mainly the N-de-alkylation and oxidation reaction.
75 citations
TL;DR: In this paper, a new and safer methodology has been developed for the synthesis of bis(pyrazol-1-yl)methane ligands (NN). Several ligands containing different phenyl groups on the central carbon atom have been obtained.
Abstract: A new and safer methodology has been developed for the synthesis of bis(pyrazol-1-yl)methane ligands (NN). Several ligands containing different phenyl groups on the central carbon atom have been obtained. Ruthenium derivatives of the type [Ru(arene)Cl(NN)]BPh4 (arene = benzene, p-cymene) have been synthesised using these ligands. One or two isomers that differ regarding the axial or equatorial disposition of the phenyl group on the metallacycle have been obtained. Their formation is rationalised by considering steric effects. The structures of five derivatives were determined by X-ray diffraction. In four complexes the phenyl substituent is in the axial disposition of the metallacycle and in one case in the equatorial orientation. The dihedral angle formed by the planes of the two pyrazole rings is always bigger for the complexes containing unsubstituted pyrazolyl heterocycles. The behaviour of the new derivatives in the transfer hydrogenation of benzophenone in the presence of KOH was studied. The benzene derivatives showed higher activity than the p-cymene complexes. A marked and positive effect of the methyl groups on the pyrazolyl rings was observed. The effect of the substituents on the benzyl carbon atom was also important. It has been observed that the benzophenone hydrogenation was possible without the addition of complexes. The effect of the KOH concentration was evaluated and a concentration that leads to negligible conversion in a base-only process was chosen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
72 citations
TL;DR: In acetonitrile, the ketone is released and complex [OsH{κ-C-(HNC5H3Et)}(NCCH3)(PiPr3)2]BF4 is formed.
Abstract: Reaction of [OsH(η2-H2){η2-C,C-κ1-N-(CH2CH-o-C5H4N)}(PiPr3)2]BF4 with benzophenone affords [OsH2{κ2-C,O−C6H4C(O)Ph}{κ-C-(HNC5H3Et)}(PiPr3)2]BF4 as a result of the orthometalation of the ketone, the hydrogenation of the vinyl substituent of the pyridine, and its subsequent tautomerization. In acetonitrile, the ketone is released and complex [OsH{κ-C-(HNC5H3Et)}(NCCH3)(PiPr3)2]BF4 is formed.
67 citations
TL;DR: The covalent attachment of a benzophenone or a naphthalene to a nitrospiropyran is not a viable strategy to improve the photocoloration efficiency of the photochromic component.
Abstract: We have designed and synthesized four compounds integrating luminescent and photochromic components in their molecular skeletons Two of them combine a nitrospiropyran photochrome with either one or two naphthalene fluorophores and can be prepared in three synthetic steps The other two consist of a nitrospiropyran photochrome and a benzophenone phosphore connected by either ether or ester linkages and can be prepared in six or five, respectively, synthetic steps The luminescent components of these assemblies are expected to transfer energy intramolecularly to the photochromic species upon excitation and encourage their photoisomerization Consistently, the phosphorescence of the benzophenone units and the fluorescence of the naphthalene components are effectively quenched when these species are connected covalently to a nitrospiropyran Nonetheless, the photoisomerization of the photochrome becomes significantly less efficient after the covalent attachment to the luminescent partner The fraction of incident radiations absorbed by either the benzophenone or the naphthalene fragment does not promote the isomerization of the photochromic appendage Instead, irreversible transformations occur upon irradiation of the luminophore-photochrome assemblies Thus, the covalent attachment of a benzophenone or a naphthalene to a nitrospiropyran is not a viable strategy to improve the photocoloration efficiency of the photochromic component Even although the very same luminophores are known to sensitize intermolecularly the isomerization of nitrospiropyrans, the transition to covalent luminophore-photochrome assemblies tends to promote degradation, rather than sensitization, upon irradiation
61 citations
TL;DR: Encapsulating Au nanoparticles within a shell of photo-cross-linked block copolymer surfactant dramatically improves the physical and chemical stability of the nanoparticles, particularly when they are applied as bioconjugates.
Abstract: Encapsulating Au nanoparticles within a shell of photo-cross-linked block copolymer surfactant dramatically improves the physical and chemical stability of the nanoparticles, particularly when they are applied as bioconjugates. Photo-cross-linkable block copolymer amphiphiles [polystyrene-co-poly(4-vinyl benzophenone)]-block-poly(acrylic acid) [(PS-co-PVBP)-b-PAA] and [poly(styrene)-co-poly(4-vinyl benzophenone)]-block-poly(ethylene oxide) [(PS-co-PVBP)-b-PEO] were assembled around Au nanoparticles ranging from 12 to 108 nm in diameter. UV irradiation cross-linked the PVBP groups on the polymer to yield particles that withstood extremes of temperature, ionic strength, and chemical etching. Streptavidin was attached to [PS-co-PVBP]-b-PAA-coated particles using the same noncovalent and covalent conjugation protocols used to bind biomolecules to divinylbenzene-cross-linked PS microspheres. We expect that these particles will be useful as plasmonic, highly light-scattering and light-absorbing analogs to fluor...
54 citations
TL;DR: In this article, new thiols and disulfides are proposed as radical polymerization photoinitiators or coinitiators, which can also be incorporated into a combination of chloro-hexaaryl bisimidazole (Cl-HABI) and a photosensitizer, such as a coumarin or ketocoumarin.
Abstract: New thiols and disulfides are proposed as radical polymerization photoinitiators or coinitiators. The drawback of the bad smell is strongly limited for the proposed compounds. Among the systems investigated, the disulfides photosensitized by isopropylthioxanthone and the tetrazole-derived thiols in the presence of benzophenone, camphorquinone, or isopropylthioxanthone have been found to be highly reactive and, in some cases, even better than a reference type I or type II photoinitiator. These thiols can also be incorporated into a combination of chloro-hexaaryl bisimidazole (Cl-HABI) and a photosensitizer, such as a coumarin or ketocoumarin. Interestingly, a photosensitizer/Cl-HABI/tetrazolethiol derivative system exhibits a higher reactivity than a commonly used photosensitizer/Cl-HABI/N-phenylglycine system. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2494–2502, 2007
50 citations
TL;DR: The water-soluble PEG-supported cinchona ammonium salts were successfully synthesized and used as chiral phase transfer catalysts for the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives with high chemical yields and enantioselectivities in aqueous media.
Abstract: The water-soluble PEG-supported cinchona ammonium salts were successfully synthesized and used as chiral phase transfer catalysts for the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives with high chemical yields (up to 98%) and enantioselectivities (up to 97%) in aqueous media. The recycling results showed that the polymers were stable and rarely lost activities.
45 citations
TL;DR: Compounds 8 and 10 have been characterized by X-ray analysis, confirming the square-planar coordination geometry of the metal center with the almost planar platinacycles and representing a new family of PtII-based luminescent complexes.
Abstract: The (benzophenone imine)platinum(II) compounds trans-[PtCl2(Ph2CNH)(RR‘SO)] [R, R‘ = Me, Me (2); n-Pr, n-Pr (3); (CH2)4 (4); Me, Ph (5); Me, p-MeC6H4 (6)] were prepared by the reaction of Ph2CNH with K[PtCl3(RR‘SO)], obtained in situ from K2[PtCl4] and the corresponding sulfoxide, giving 2−6 as well as cis-[PtCl2(Ph2CNH)2] (1) as a minor product. The complexes were characterized by 1H, 13C, and 195Pt NMR and IR spectroscopy, electrospray ionization mass spectrometry, and C, H, and N elemental analysis. The X-ray crystallography of 1 enables confirmation of the cis configuration of the complex, while in 2 and 4·1/2CHCl3, the imine and sulfoxide ligands are mutually trans. The solid-state structure of 4·1/2CHCl3 consists of two dimeric Pt moieties representing a rather weak Pt···Pt interaction. The dimeric architecture of 4·1/2CHCl3 is enhanced by the hydrogen bonding between imine H atoms and O atoms. The orthometalation of 1 and 2−6 proceeds both in the solid phase and in a toluene suspension, leading to ...
TL;DR: A nanosecond time-resolved resonance Raman (ns-TR3) spectroscopic study of the triplet state benzophenone reaction with the 2-propanol hydrogen-donor solvent and subsequent reactions is presented.
Abstract: A nanosecond time-resolved resonance Raman (ns-TR3) spectroscopic study of the triplet state benzophenone reaction with the 2-propanol hydrogen-donor solvent and subsequent reactions is presented. The TR3 spectra show that the benzophenone triplet state (nπ*) hydrogen-abstraction reaction with 2-propanol is very fast (about 10 to 20 ns) and forms a diphenylketyl radical and an associated 2-propanol radical partner. The temporal evolution of the TR3 spectra also indicates that recombination of these two radical species occurs with a time constant of about 1170 ns to produce a LAT (light absorbing transient) intermediate that is identified as the 2-[4-(hydroxylphenylmethylene)cyclohexa-2,5-dienyl]propan-2-ol (p-LAT) species. Comparison of the TR3 spectra with results obtained from density functional theory calculations for the species of interest was used to elucidate the identity, structure, properties, and major spectral features of the intermediates observed in the TR3 spectra. The structures and propert...
TL;DR: In this article, the photopolymerization of difunctional 1,6-hexanediol diacrylate (HDDA) was studied by photo-DSC to investigate the photoefficiency of the copolymers, homopolymers and the combination of their hompolymers.
Abstract: Novel polymeric sulfur-containing photoinitiators bearing side-chain benzophenone and coinitiator amine, copolymers of 4-[(4-methacrylamido)thiophenyl]benzophenone (MAATPBP) and of 4-chloro-4′-[(4-methacrylamido)thiophenyl]benzophenone (CMAATPBP) with N,N-dimethylaminoethyl methacrylate (DMAEMA), as well as their hompolymers of poly(MAATPBP), poly(CMAATPBP) and poly(DMAEMA) were prepared and structurally characterized. The most commercially used photoinitiator BP and their corresponding low molecular weight combinations (MAATPBP/DMAEMA and CMAATPBP/DMAEMA) were selected as the reference to evaluate their photoefficiency. Polymeric photoinitiators display similar UV–vis maximal absorption spectra to the low molecular counterparts, which are greatly red-shifted in comparison with BP. Photopolymerization of difunctional 1,6-hexanediol diacrylate (HDDA) and trifunctional trimethylolpropane triacrylate (TMPTA) were studied by photo-DSC to investigate the photoefficiency of the copolymers, homopolymers and the combination of their homopolymers. The results show surprising high efficiency of the two copolymeric photoinitiators and their homopolymeric combinations. Poly(MAATPBP) and poly(CMAATPBP) can also efficiently initiate the photopolymerization without the coinitiator because of the photolysis at C–S bond. Their activity data obtained are discussed and related to the structural requirements of the above systems.
TL;DR: The magnetic field effects (MFEs) on photoinduced hydrogen abstraction reactions of benzophenone (BP) with thiophenol (PhSH) in the ionic liquids (ILs) N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl) imide (TMPA TFSI), N-methyl- N-propylpyrrolidinium bis
Abstract: The magnetic field effects (MFEs) on photoinduced hydrogen abstraction reactions of benzophenone (BP) with thiophenol (PhSH) in the ionic liquids (ILs) N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl) imide (TMPA TFSI), N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl) imide (P13 TFSI), and N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl) imide (PP13 TFSI) were investigated at 296 K by using a nanosecond laser flash photolysis technique under magnetic fields of 0-1.7 T. Large MFEs were observed for the first time in the ILs. In TMPA TFSI, the yield of the benzophenone ketyl radical gradually decreased with increasing magnetic field strength from 0 to 1.7 T, producing a 20% decrease at 1.7 T.
TL;DR: In this article, the metastable zone width and inductions periods of benzophenone in CHCl3 and CCl4 were determined using induction period, and the nucleation parameters, such as the radius of the critical nuclei (r*), the free energy change for the formation of a critical nucleus (ΔG*) and the number of molecules in the critical nucleus were also calculated.
Abstract: Benzophenone is a well-known material, which exhibits non-linear optical (NLO) property. It has been grown by solution technique adopting slow evaporation method from solvents CHCl3, CCl4 for the first time. Solubility metastable zone width and inductions periods of benzophenone in CHCl3 and CCl4 were determined. Interfacial tension values at two different temperatures for various super saturations, such as 1.10, 1.15, 1.20 and 1.25 were determined using induction period. From interfacial tension values, the nucleation parameters, such as the radius of the critical nuclei (r*), the free energy change for the formation of a critical nucleus (ΔG*) and the number of molecules in the critical nucleus were also calculated for benzophenone in CHCl3 and CCl4 at two different temperature. The effect of surface tension, viscosity, density of these solvents are correlated with interfacial tension. The metastable zone width is also correlated with interfacial tension. The solution grown crystals were carefully harvested and subjected to various characterization studies to check its purity and to determine its applicability.
TL;DR: The data indicate that conjugated dienes can be used as specific quenchers of triplet carbonyls formed in biological systems during oxidative stress and suggest that the well-known food preservative properties of sorbate may be due to its tripletcarbonyl quenching activity.
Abstract: Electronically excited triplet carbonyls are formed during the oxidative degradation of polyunsaturated fatty acids, amino acids, and beta-dicarbonyl metabolites. Due to their long lifetime and high alkoxyl radical-like reactivity, triplet carbonyls may initiate deleterious reactions in biological systems. Here we study the quenching properties of conjugated dienes, specifically 2,4-hexadienoate (sorbate) and its alkyl ester, on triplet acetone generated chemically (thermolysis of tetramethyl-1,2-dioxetane) or enzymatically (horseradish peroxidase-catalyzed aerobic oxidation of isobutanal). Triplet acetone quenching rates were near diffusion control ( k q = 10 (8)-10 (9) M (-1) s (-1)) and accompanied by diene cis-trans isomerization. None of the dienes displays antioxidant activity in classical systems known to generate reactive oxygen species: superoxide anion radical, hydroxyl radical, alkoxyl and alkylperoxyl radicals, or singlet oxygen. Experiments with model systems used widely to study lipid peroxidation showed that sorbate can inhibit mitochondrial swelling induced by enzymically formed triplet benzophenone and quench the chemiluminescence of microsome preparations challenged with iron and ascorbate. Altogether, our data indicate that conjugated dienes can be used as specific quenchers of triplet carbonyls formed in biological systems during oxidative stress. Moreover, they suggest that the well-known food preservative properties of sorbate may be due to its triplet carbonyl quenching activity.
TL;DR: In this article, the reduction of benzophenone (Bzph) in 3-pentanone (PEN), acetone (ACE), N,N-dimethylacetamide (DMF), tetrahydrofuran (THF), acetonitrile (ACN) and dimethyl sulfoxide (DMSO) with n-tetrabutylammonium hexafluorophosphate (TBAPF6) as background electrolyte was studied using the technique of cyclic voltammetry at the temperature of 263.15 K.
Abstract: The reduction of benzophenone (Bzph) in 3-pentanone (PEN), acetone (ACE), N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), acetonitrile (ACN) and dimethyl sulfoxide (DMSO) with n-tetrabutylammonium hexafluorophosphate (TBAPF6) as background electrolyte was studied using the technique of cyclic voltammetry at the temperature of 263.15 K. The half-wave potentials (E
1/2) were extracted. The reduction of Bzph occurs in two successive one-electron steps to produce first the free radical anion Bzph− and then the dianion Bzph2−. The results indicated that the radical anion Bzph− is reoxidized to Bzph in all investigated solvent media whereas the dianion Bzph2− is reoxidized to Bzph− only in THF. The heterogeneous electron-transfer rate constants (k
s
) were evaluated by employing the electrochemical rate equation proposed by Nicholson. The rate of electron transfer for the Bzph/Bzph− couple was found to be relatively slow in all investigated solvent media. Consequently, the electron-transfer processes can be recognized as quasi-reversible. The diffusion coefficients (D) of Bzph in the investigated solvent media have been calculated using the modified Randles-Sevcik equation. The effect of the physical and chemical properties of the solvent medium on the electrochemical behavior of Bzph has been examined.
TL;DR: Nanocrystals suspended in water can be used to record steady state and pump-probe absorption spectra, which should be useful for the study of excited states and reactive intermediates in the solid state.
TL;DR: Interestingly, a highly regio- and stereoselective macrocyclization has been found for the ketoprofen-tetrahydrofuran conjugates, where hydrogen abstraction from the less substituted carbon is exclusive; cisoid ring junction is always preferred over the transoid junction.
Abstract: Intramolecular excited triplet state interactions in diastereomeric compounds composed of a benzophenone chromophore (ketoprofen) and various hydrogen donor moieties (tetrahydrofuran, isopropylbenzene) have been investigated by laser flash photolysis. The rate constants for hydrogen abstraction by excited triplet benzophenone are in the order of 104−105 s-1, with the highest reactivity for the tetrahydrofuran residue. A remarkable diastereodifferentiation, expressed in the triplet lifetimes of the carbonyl chromophore (e.g., 1.6 versus 2.7 μs), has been found for these compounds. With an alkylaromatic moiety as donor, related effects have been observed, albeit strongly dependent on the length of the spacer. The reactivity trend for the initial hydrogen transfer step is paralleled by the quantum yields of the overall photoreaction. The biradicals, formed via remote hydrogen abstraction, undergo intramolecular recombination to macrocyclic ring systems. The new photoproducts have been isolated and characteri...
TL;DR: Although this complex is a poor emitter, an analogous complex obtained from 2-amino-acetophenone, which generates 4-methyl-2-hydroxyquinoline during the corresponding rearrangement is an order of magnitude more emissive while still benefiting from relatively long-wavelength absorption.
Abstract: A series of europium(III) complexes based on the macrocyclic azacarboxylate structure, DO3A, have been investigated, incorporating benzophenone appended at N10 of the macrocycle via linkers containing amide bonds (H3DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-tris-acetic acid). Complexes [EuL(1-3)] incorporate N10-CH2CONH-BP linkers (BP = benzophenone), which allow formation of a five-membered chelate ring containing the metal ion upon chelation of the amide oxygen; these three isomeric complexes differ from one another in the substitution position of the BP unit, namely para, meta, and ortho for L1, L2, and L3 respectively. The quantum yields of europium luminescence sensitized via the chromophore are found to be highly dependent upon the position of substitution, being 20 times smaller for the ortho compared to the para-substituted complex. A related para-substituted BP complex [EuL(4)], prepared by an unusual Michael reaction of the azamacrocycle with a BP-containing acrylamide, incorporates an additional methylene unit in the linker, namely N10-CH2CH2CONH-BP. Despite the longer linker, this complex equals the luminescence quantum yield achieved with [EuL(1)] (Phi(lum) = 0.097 and 0.095, respectively, in H2O at 298 K). Analysis of the pertinent kinetics reveals that the decreased energy transfer efficiency in this complex, arising from the longer donor-acceptor distance, is compensated by an increased radiative rate constant. Under basic conditions, the ortho-substituted complex [EuL(3)] undergoes an intramolecular rearrangement to generate an unprecedented complex [EuL(5)] incorporating a 4-phenyl-2-hydroxyquinoline unit directly bound to the ring nitrogen. Although this complex is a poor emitter, an analogous complex obtained from 2-amino-acetophenone, which generates 4-methyl-2-hydroxyquinoline during the corresponding rearrangement, is an order of magnitude more emissive while still benefiting from relatively long-wavelength absorption. The emission from this complex is pH sensitive, being dramatically quenched under mildly basic conditions.
TL;DR: In this article, Friedel-Crafts acylation reactions using ionic liquids (ILs) of BmimCl-FeCl3, BmCl-AICl(3) and Bmcl-ZnCl2 as dual catalyst-solvent were shown to have higher catalytic activity than that observed for the other two ILs.
TL;DR: Out of the compounds studied, the compounds 4c, 4e, 4g, 4h and 4k with chloro and methyl substituents at para position showed more potent activity than the standard drugs at all doses tested.
TL;DR: In this article, the crystallization behavior and crystal structure of PVDF in PVDF/benzophenone systems were investigated by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD).
Abstract: Microporous poly(vinylidene fluoride) (PVDF) membranes were prepared by thermally induced phase separation (TIPS) at different quenching temperatures with benzophenone as the diluent. The crystallization behavior and crystal structure of PVDF in PVDF/benzophenone systems were investigated by differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD). The different PVDF concentrations had a remarkable effect on PVDF crystallization behavior and resulted in different membrane structures. Spherulitic structures were vague when the PVDF/benzophenone solution was quenched to −8°C; however, discernable spherulitic structures were obtained when quenched to 34 and 49°C. Additionally, two phase separation mechanisms (solid–solid (S–S) and solid–liquid (S–L) phase separation) were observed during membrane preparation. It was revealed by scanning electron microscopy (SEM) that microporous membranes had more discernable spherulitic structures formed by S–L phase separation than by S–S phase separ...
TL;DR: In this article, a method for covalent sidewall functionalization of single-walled carbon nanotubes via one-electron reduction of benzophenone by potassium was reported.
TL;DR: In this article, the possibility of existence of an excited electronic state in the region bellow 200 nm has been explored using density functional theory to correlate the observed vibrational spectra.
TL;DR: The synthetic importance of the beta,gamma-aziridino alpha-amino ester derivatives is demonstrated by their conversion into the corresponding Boc-protected derivatives and ring opening reactions to alpha,beta-diamino esters and a gamma-aminos alpha, beta-unsaturated amino ester.
Abstract: Mannich-type addition of benzophenone imine glycinates across newly synthesized N-(p-toluenesulfonyl) α-chloroaldimines afforded γ-chloro-α,β-diamino ester derivatives with moderate diastereoselectivity as separable mixtures of anti and syn diastereomers. The γ-chloro-α,β-diamino esters were efficiently cyclized under basic conditions to the corresponding β,γ-aziridino α-amino ester derivatives, representing a new class of conformationally constrained heterocyclic α,β-diamino acid derivatives. The relative configuration of the aziridines was determined via X-ray diffraction analysis. Mechanisms and intermediate transition states to explain the stereochemical outcome of the Mannich reaction with different substrates or under different conditions are proposed. The synthetic importance of the β,γ-aziridino α-amino ester derivatives is demonstrated by their conversion into the corresponding Boc-protected derivatives and ring opening reactions to α,β-diamino esters and a γ-amino α,β-unsaturated amino ester.
TL;DR: In preparation of self-decontamination clothing materials in high reactivities against toxic agents, photoactive benzophenone chromophoric groups were incorporated into cotton fabrics by using 4-hydroxybenzophenone as a reagent, 1,2,3,4,-butanetetra carboxylic acid (BTCA) as a crosslinker, and sodium hypophosphite as a catalyst.
Abstract: In preparation of self-decontamination clothing materials in high reactivities against toxic agents, photoactive benzophenone chromophoric groups were incorporated into cotton fabrics. The cotton fabrics were treated by using 4-hydroxybenzophenone as a reagent, 1,2,3,4,-butanetetra carboxylic acid (BTCA) as a crosslinker, and sodium hypophosphite as a catalyst. The fabric treat- ment was conducted by a pad-dry-cure method. The benzophenone chromophoric group incorporated cotton fabrics were characterized by FTIR, SEM, TGA, and so on. The results confirmed the expected structures of the benzo- phenone chromophoric group modified and BTCA cross- linked cotton fabrics. The treated cotton fabrics demon- strated radical reactivities and antibacterial activity under UV irradiation. 2007 Wiley Periodicals, Inc. J Appl Polym Sci 106: 2661-2667, 2007
05 Jan 2007
TL;DR: In this paper, a comparative study of catalytic and electrocatalytic hydrogenation of benzophenone was performed in aqueous ethanol on 10% (w/w) Pd-alumina supported catalyst and finely divided Pd catalyst.
TL;DR: In this article, two kinds of polymeric photoinitiators, PUPIA and PUPI, were synthesized through the polycondensation of toluene-2,4-diisocyanate with AATBP and/or N-methyldiethanolamine (MDEA).
Abstract: A novel thio-containing diamine with a benzophenone structure, 4-amino-4′-[4-aminothiophenyl]benzophenone (AATBP), was synthesized. Two kinds of polymeric photoinitiators, PUPIA and PUPI, were synthesized through the polycondensation of toluene-2,4-diisocyanate with AATBP and/or N-methyldiethanolamine (MDEA). A macroamine, PUPA, was also synthesized for comparison. Fourier transform infrared, 1H NMR, and gel permeation chromatography analyses confirmed the structures of all the polymers. The ultraviolet–visible spectra of PUPIA, PUPI, and AATBP were similar, and all exhibited the maximal absorption above 325 nm. The photopolymerization of two monomers with different functionalities, poly(propylene glycol)diacrylate and trimethylolpropane triacrylate initiated by PUPIA, PUPI/MDEA, PUPI/PUPA, AATBP/MDEA, and AATBP/PUPA, was studied through differential scanning photocalorimetry. The results showed that both PUPIA and PUPI/MDEA had high photoefficiency, and their low-molecular-weight counterparts could hardly initiate the photopolymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 576–587, 2007