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Showing papers on "Benzophenone published in 2003"


Journal ArticleDOI
TL;DR: In this paper, a series of imines of glycine esters derived from glycine and aromatic carbonyl compounds has been screened as substrates for the Mannich reaction with different imines in the presence of various combinations of metal salts and chiral ligands.
Abstract: Imines of glycine alkyl esters react with imines in a diastereo- and highly enantioselective Mannich reaction in the presence of chiral copper(I) complexes as the catalyst to give optically active α,β-diamino acid derivatives. A series of imines of glycine esters derived from glycine and aromatic carbonyl compounds has been screened as substrates for the Mannich reaction with different imines in the presence of various combinations of metal salts and chiral ligands. The benzophenone imine of glycine esters was found to react with N-protected imines in a diastereoselective fashion giving functionalized α,β-diamino acid esters with excellent enantioselectivities. The most effective chiral catalysts are chiral copper(I) complexes having phosphino-oxazoline (P,N)-ligands, and among these ligands, those derived from (1R,2S)-dihydroxy-1,2,3,4-tetrahydronaphthalene gave the best results. The scope of this new catalytic asymmetric reaction of the benzophenone imine glycine esters is demonstrated for the reaction ...

133 citations



Journal ArticleDOI
TL;DR: In this paper, the effect of the hydroxyl group in the phenol moiety were in order of 4- > 3- > 2-position, while the chloro group added at the 2 position of the 4-hydroxylated benzene ring enhanced the activity.
Abstract: UV stabilizers used in food contact plastics were tested for their estrogenic activity by the yeast two-hybrid assay. Among 11 kinds of UV stabilizers, 2-hydroxy- 4-methoxybenzophenone and 2,2′-dihydroxy-4-methoxybenzophenone displayed estrogenic activity, while salicylate, benzoate and benzotriazole derivatives and a benzophenone derivative had no activity. Therefore, benzophenone and 19 kinds of hydroxylated derivatives were further studied. Of these, 15 chemicals showed estrogenic activity. The strongest activity was by 2,4-dihydroxybenzophenone, 4-hydroxy-4′-chlorobenzophenone, 4-hydroxybenzophenone and 2,3,4-trihydroxybenzophenone. Their activities were stronger than that of bisphenol A which was recognized as a potential endocrine disruptor. The following structure-activity relationships of benzophenones were obtained. The activity of the benzophenones with a hydroxyl group at the 3 or 4-position was positive and rather strong, though that of other benzophenones without a hydroxyl group at the 3 or 4-position was negative or weakly positive. The effect of the hydroxyl group in the phenol moiety were in order of 4- > 3- >> 2-position. A hydroxyl group added at the 2-position of the 4-hydroxylated benzene ring enhanced the activity. On the other hand, a hydroxyl group added to the benzene ring of the hydrophobic moiety reduced the binding, while the chloro group enhanced it. Some of these relationships might possibly hold for other estrogenic chemicals that possess two benzene rings.

109 citations


Journal ArticleDOI
TL;DR: In this paper, the role of benzophenone (BP) in the formation of copper metal nanoparticles was studied and it was shown that the presence of BP is essential for the photochemical preparation of copper nanoparticles.

105 citations


Journal ArticleDOI
TL;DR: The lowest triplet state of tris(8-hydroxyquinoline)aluminium(III) (Alq3) has been prepared by pulse radiolysis/energy transfer from appropriate donors in benzene solutions and has an absorption maximum around 510 nm with a lifetime of about 50 mus.
Abstract: The lowest triplet state of tris(8-hydroxyquinoline)aluminium(III) (Alq3) has been prepared by pulse radiolysis/energy transfer from appropriate donors in benzene solutions and has an absorption maximum around 510 nm with a lifetime of about 50 μs. It is quenched by molecular oxygen, leading to singlet oxygen formation. From flash photolysis and singlet oxygen formation measurements, a quantum yield of triplet formation of 0.24 was determined for direct photolysis of the complex. A value of 2.10 ± 0.10 eV was determined for the energy of the lowest triplet state by energy transfer studies and was confirmed by phosphorescence measurements on Alq3, either in the heavy atom solvent ethyl iodide or photosensitized by benzophenone in benzene. Dexter (exchange) energy transfer was observed from triplet Alq3 to platinum(II) octaethylporphyrin.

105 citations


Journal ArticleDOI
TL;DR: Complexes 2 and 3 were characterized by elemental analyses, UV/Vis, IR, and ESR spectroscopy, as well as by single crystal X-ray diffraction.
Abstract: The reduction of benzophenone with the magnesium complex [(2,6-iPr2C6H3-bian)Mg(thf)3] (1), containing the 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene dianion, affords the pinacolato complex [(2,6-iPr2C6H3-bian)Mg(thf)]2[μ-O2C2Ph4]⋅(C6H6)4 (2). The reaction of 1 with 9(10H)-anthracenone yields the 9-anthracenolato complex [(2,6-iPr2C6H3-bian)Mg(OC14H9)(thf)2] (3). Complexes 2 and 3 were characterized by elemental analyses, UV/Vis, IR, and ESR spectroscopy, as well as by single crystal X-ray diffraction. Complex 2 dissociates in solution with splitting of the bridging pinacolato unit, forming the biradical diimino/ketyl complex [(2,6-iPr2C6H3-bian)Mg(thf)(OCPh2)].

87 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the reactions of hydrogen atoms with pyrene, phenanthrene, benzophenone, 2-propanol, and crotonic acid in the ionic liquid methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide (R4NNTf2) by pulse radiolysis.
Abstract: Reactions of hydrogen atoms with pyrene, phenanthrene, benzophenone, 2-propanol, and crotonic acid in the ionic liquid methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide (R4NNTf2) were studied by pulse radiolysis. Radiolysis of the ionic liquid leads to formation of dry electrons and solvated electrons, which are scavenged by H3O+ to produce H• atoms. Hydrogen atoms react very rapidly with pyrene (3.8 × 109 L mol-1 s-1) and phenanthrene (2.9 × 109 L mol-1 s-1) to form H-adduct radicals with sharp absorption peaks at 405 and 395 nm, respectively. They also react with benzophenone to form ring adducts, but the reaction is much slower. By competition kinetics with pyrene, the rate constants for reactions of H• atoms with 2-PrOH and with crotonic acid were estimated to be ≈6 × 107 and 4.6 × 109 L mol-1 s-1, respectively. All the rate constants, except for benzophenone, are similar to the values measured or estimated for the same reactions in aqueous solutions. The reactions with the aromatic hydrocarb...

84 citations


Journal ArticleDOI
TL;DR: The title compounds were synthesised and characterised as part of a study into new aromatic amines for charge transporting materials as mentioned in this paper, and each compound was characterised by cyclic voltammetry.

79 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the triplet state of aromatic ketones quenched by protons and found that the rate of protonation of 31, kH+ = 6.8 × 108 M-1 s-1, is well below the diffusion-controlled limit.
Abstract: Why is the triplet state of aromatic ketones quenched by protons? The long-known but unexplained quenching process was investigated in detail for benzophenone (1). Adiabatic protonation of triplet benzophenone, 31, encounters a state symmetry-imposed barrier, because the electronic structure of 31 is n,π*, while that of its conjugate acid, 31H+, is π,π*. Hence, the rate of protonation of 31, kH+ = 6.8 × 108 M-1 s-1, is well below the diffusion-controlled limit. The short-lived transient intermediate formed by protonation of 31 in 0.1−1 M aqueous HClO4 (λmax = 320 and 500 nm, τ = 50 ns) is not 31H+, as was assumed in previous studies. The latter (λmax = 385 nm) is detectable only in acidified acetonitrile or in highly concentrated aqueous acid (>5 M HClO4), where water activity is low. In moderately concentrated aqueous acids, adiabatic protonation of 31 is the rate-limiting step preceding rapid adiabatic hydration of a phenyl ring, 31H+ + H2O → 31·H2O, k0 = 1.5 × 109 s-1. These findings lead to a revised ...

71 citations


Journal ArticleDOI
TL;DR: The approach combined testing of the compounds first for increased binding affinity and for increased stability in vitro, and most promising compounds were then evaluated for their efficacy in lowering plasma total cholesterol (TC) and plasma low-density lipoprotein cholesterol (LDL-C) in hyperlipidemic hamsters.
Abstract: New orally active non-terpenoic inhibitors of human 2,3-oxidosqualene cyclase (hOSC) are reported. The starting point for the optimization process was a set of compounds derived from a fungicide project, which in addition to showing high affinity for OSC from Candida albicans showed also high affinity for human OSC. Common structural elements of these inhibitors are an amine residue and an electrophilic carbonyl C atom embedded in a benzophenone system, which are at a distance of about 10.7 A. Considering that the keto moiety is in a potentially labile position, modifications of the substitution pattern at the benzophenone as well as annelated heteroaryl systems were explored. Our approach combined testing of the compounds first for increased binding affinity and for increased stability in vitro. Most promising compounds were then evaluated for their efficacy in lowering plasma total cholesterol (TC) and plasma low-density lipoprotein cholesterol (LDL-C) in hyperlipidemic hamsters. In this respect, the most promising compounds are the benzophenone derivative 1.fumarate and the benzo[d]isothiazol 24.fumarate, which lowered TC by 40% and 33%, respectively.

55 citations


Journal ArticleDOI
TL;DR: An efficient large-scale method for the preparation of 2-[N-(α-picolyl)amino]acetophenone (PAAP) and 2-[n-amino]-benzophenone(PABP) with NiII complexes with glycine is described in this paper.

Journal ArticleDOI
TL;DR: In this paper, a pentagonal bipyramid with the phosphorus atoms of the phosphines occupying axial positions was determined by X-ray diffraction analysis, and the reaction pathway for the formation of this intermediate was evaluated by DFT calculations.

Journal ArticleDOI
TL;DR: Imidazolidenyl carbene catalyzes nucleophilic acylation reaction of arylfluorides with electron withdrawing groups to give benzophenone derivatives.

Journal ArticleDOI
TL;DR: In this article, the estrogenic activities of S-9 metabolites of benzophenone derivatives (benzophenone, 2-hydroxy-4-methoxybenzphenone derivatives, 2,2′-dihydrox-4)-4methioxethenone derivatives and benzhydrol derivatives were examined with a yeast two-hybrid screening system.
Abstract: The estrogenic activities of S-9 metabolites of benzophenone derivatives (benzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone and 2,3,4-trihydroxybenzophenone) and benzhydrol were examined with a yeast two-hybrid screening system. After chemicals were incubated in an S-9 mix at 37°C for 4 hr prior to their incubation with the yeast strain, the S-9 mix containing metabolites was assayed for the estrogenic activity by the yeast two-hybrid assay. Benzophenone, 2-hydroxy-4-methoxybenzophenone and 2,2′-dihydroxy-4-methoxybenzophenone exhibited estrogenic activities after incubation with the S-9 mix. The estrogenic metabolites of 2-hydroxy-4-methoxybenzophenone were fractionated by high-performance liquid chromatography, one of which was identified as 2,4-dihydroxybenzophenone. This assay will be a useful tool for detecting proestrogens.

Journal ArticleDOI
TL;DR: Binaphthyl-modified spiro-type symmetrical phase-transfer catalysts possessing 4,4′,6,6′-tetraaryl substituents were shown to exhibit high asymmetric induction in asymmetric alkylation of benzophenone imine glycine tert -butyl ester under ordinary phase transfer conditions as discussed by the authors.
Abstract: Binaphthyl-modified spiro-type symmetrical phase-transfer catalysts possessing 4,4′,6,6′-tetraaryl substituents are shown to exhibit high asymmetric induction in asymmetric alkylation of benzophenone imine glycine tert -butyl ester under ordinary phase-transfer conditions.

Journal ArticleDOI
TL;DR: In this paper, the pKa values of 4(OH)benzophenone, 2(OH),4(CH3O)bensophenone and 2(HO),4HObensphenone in ethanol-water solutions, varying solvent permittivity in the interval 61-72, at constant ionic strength (0.050) and temperature (25.0±0.1 ǫ) were determined.
Abstract: Benzophenones are compounds of great importance due to their biological and physicochemical properties. The purpose of the present work was to determine by a UV–Visible spectroscopic method, the pKa of 4(OH)benzophenone, 2(OH)benzophenone and 2(OH),4(CH3O)benzophenone in ethanol–water solutions, varying solvent permittivity in the interval 61–72, at constant ionic strength (0.050) and temperature (25.0±0.1 °C). The pKa values of the compounds increase when the polarity–polarizability and solvation abilities of the reaction medium decrease. Correlations were established between the pKa values and solvation parameters of the solvents, such as the relative permittivity, the α parameter of Taft the solvatochromatic polarity–polarizability parameter π ∗ , and the parameter Acity. Excellent linear equations were obtained from which pKa values were determines in pure water. The structures of all the chemical species involved in the acid–base dissociation equilibria studied were calculated at the RHF/6-31G(d) level of theory, in ethanol and water. Considering the theoretical pKa values, the conclusions obtained match our experimental determinations.

Journal ArticleDOI
TL;DR: In this article, a four component system consisting of bis[2-(o-chlorophenyl)-4,5-diphenylimidazole] (Cl-HABI), N,N′-bis(diethylamino)benzophenone (EAB), N-phenylglycine (NPG) and an iodonium salt (BIP-T) can be used for the photoinitiation of radical polymerization reactions.
Abstract: The four component system consisting of bis[2-(o-chlorophenyl)-4,5-diphenylimidazole] (Cl-HABI), N,N′-bis(diethylamino)benzophenone (EAB), N-phenylglycine (NPG) and an iodonium salt (BIP-T) can be used for the photoinitiation of radical polymerization reactions. The excited state processes involved are reported and all the transient species, including the triplet state and ketyl radical of EAB as well as the lophyl radical, are characterized. Rate constants of interaction between the different partners in the four component system are determined. Redox potentials of the different compounds are evaluated enabling the free energies for electron transfer reactions to be calculated. An overall scheme for the evolution of the excited states and a general discussion on the role played by the different components in photoinitiating polymerization are then provided.

Journal ArticleDOI
TL;DR: In this article, a binaphthyl-modified spiro-type phase-transfer catalysts possessing 4,4′-diaryl substituents were shown to exhibit high asymmetric induction in asymmetric benzylation of benzophenone imine glycine tert -butyl ester under phase transfer conditions.

Journal ArticleDOI
TL;DR: A photoreactive organic polymer was prepared by oxidative electrochemical polymerization of a pyrrole-benzophenone derivative on conductive surfaces; the resulting polypyrrolic film allowed, upon irradiation, the reagentless covalent grafting of proteins.

Journal ArticleDOI
TL;DR: In this paper, a single-stage synthesis of β-aryl-α,β-unsaturated aldehydes using photosensitised hydrogen abstraction of benzophenone was proposed.

Journal ArticleDOI
TL;DR: Using two diastereomeric compounds containing benzophenone and olefin units, significant chiral discrimination has been found in all the photophysical and photochemical processes involved in intramolecular hydrogen abstraction as discussed by the authors.

Journal ArticleDOI
TL;DR: The first photoreactive low-molecular weight organogels are described in this article, where benzophenone derivatives functionalised with two long alkylamides 1a-c were designed and synthesized as photore active gelator molecules.
Abstract: In this paper, first photoreactive low-molecular weight organogels are described. Benzophenone derivatives functionalised with two long alkylamides 1a–c were designed and synthesized as photoreactive gelator molecules. The compounds formed organogels in several hydrogen donor solvents, e.g. 2-propanol and 1,3,5-triisopropylbenzene. Microstructures of the gels by scanning electron microscopy (SEM) revealed a 3D fibrous network and spherical aggregation. Compound 4 based on isopropylbenzene having an octadecylamide, which was designed as a photochemical hydrogen donor molecule, occurred gelation in a variety of organic solvents. In the case of a 1:1 mixture of 1c and 4 in several solvents, each component independently caused gelation to give a simple mixture of different gels. Irradiation of the gel of 1a in 2-propanol decomposed gradually the gel into solution to give pinacol as a main product. Similarly, photoreaction of the 1:1 two-component gel of 1c and 4 in benzene afforded corresponding pinacol.

Journal ArticleDOI
TL;DR: In this article, the transition metal catalysed reactions of benzaldehydes and benzylideneamines with disilanes have been investigated, and the reaction of benzophenone with the difluorodisilane formed 2,2-dimethyl-4,4,5,5-tetraphenyl-1,3dioxa-2-silacyclopentane without affording the corresponding simple double silylation product.
Abstract: The transition metal catalysed reactions of benzaldehydes and benzylideneamines with disilanes have been investigated. Palladium phosphine complexes catalyse the double silylation of the CO bond in benzaldehydes and the CN bond in benzylideneamines with 1,2-difluoro-1,1,2,2-tetramethyldisilane to yield α-(fluorodimethylsilyl)-α-(fluorodimethylsiloxy)toluene and N-methyl-N-(fluorodimethylsilyl)-α-(fluorodimethylsilyl)benzylamine respectively. When less activated disilanes such as 1,2-dichloro- and 1,2-dimethoxy-1,1,2,2-tetramethyldisilane were employed, the palladium phosphine complexes were less active and selective, resulting in extensive side reactions inclusive of 1,2-disiloxy-1,2-diphenylethane formation. The reaction of benzophenone with the difluorodisilane formed 2,2-dimethyl-4,4,5,5-tetraphenyl-1,3-dioxa-2-silacyclopentane without affording the corresponding simple double silylation product. The formation of side products such as 1,2-disiloxy-1,2-diphenylethane in the reaction of benzaldehyde and 2,2-dimethyl-4,4,5,5-tetraphenyl-1,3-dioxa-2-silacyclopentane in the reaction of benzophenone appears to suggest intermediacy of radical and silylene species. Tris(dibenzylideneacetone)diplatinum–etpo (etpo = 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane catalyst system was more active for unactivated disilanes, catalysing double silylation of benzaldehydes with hexamethyldisilane. The same catalyst system was found to catalyse the ortho silylation of benzylideneamines with disilanes via intramolecular C–H activation; both mono- and bis-silylated products were obtained. Reaction rates and product distributions are rationalised in terms of the steric and electronic properties of the disilanes, substrates and the catalyst used.

Journal ArticleDOI
TL;DR: Product analysis and identification clearly show that the two main degradation photoproducts following laser excitation in the propylated substrates are 1-phenyl-1,2-propanedione and 2-hydroxybenzophenone, although several other minor photodegradation products were identified.
Abstract: Laser-induced room temperature luminescence of air-equilibrated benzophenone/O-propylated p-tert-butylcalix[4]arene solid powdered samples revealed the existence of a novel emission, in contrast with benzophenone/p-tert-butylcalix[4]arene complexes, where only benzophenone emits. This novel emission was identified as phosphorescence of 1-phenyl-1,2-propanedione, which is formed as the result of an hydrogen atom abstraction reaction of the triplet excited benzophenone from the propoxy substituents of the calixarene. Room temperature phosphorescence was obtained in air-equilibrated samples in all propylated hosts. The decay times of the benzophenone emission vary greatly with the degree of propylation, the shortest lifetimes being obtained in the tri- and tetrapropylated calixarenes. Triplet–triplet absorption of benzophenone was detected in all cases, and is the predominant absorption in the p-tert-butylcalix[4]arene case, where an endo-calix complex is formed. Benzophenone ketyl radical formation occurs with the O-propylated p-tert-butylcalix[4]arenes hosts, suggesting a different type of host/guest molecular arrangement. Diffuse reflectance laser flash photolysis and gas chromatography–mass spectrometry techniques provided complementary information, the former about transient species and the latter regarding the final products formed after light absorption. Product analysis and identification clearly show that the two main degradation photoproducts following laser excitation in the propylated substrates are 1-phenyl-1,2-propanedione and 2-hydroxybenzophenone, although several other minor photodegradation products were identified. A detailed mechanistic analysis is proposed. While the solution photochemistry of benzophenone is dominated by the hydrogen abstraction reaction from suitable hydrogen donors, in these solid powdered samples, the α-cleavage reaction also plays an important role. This finding occurs even with one single laser pulse which lasts only a few nanoseconds, and is apparently related to the fact that scattered radiation exists, due to multiple internal reflections possibly trapping light within non-absorbing microcrystals in the sample, and is detected until at least 20 µs after the laser pulse. This could explain how photoproducts thus formed could also be excited with only one laser pulse.

Patent
03 Dec 2003
TL;DR: In this paper, amino substituted hydroxyphenyl benzophenone derivatives of formula (I) are described, wherein R1 and R2 independently from each other are; C1, C20alkyl, C2-C20alky, C3-C10, cycloalkyl; C3 -C10cycloalkenyl; or R1, R2 together with the linking nitogen atom form a 5- or 6-membered heterocyclic ring; n1 is a number from 1 to 4; when n1=
Abstract: Described are amino substituted hydroxyphenyl benzophenone derivatives of formula (I), wherein R1, and R2 independently from each other are; C1,-C20alkyl; C2-C20alkenyl; C3-C10,cycloalkyl; C3-C10cycloalkenyl; or R1, and R2 together with the linking nitogen atom form a 5- or 6-membered heterocyclic ring; n1 is a number from 1 to 4; when n1=1, R3 is a saturated or unsaturated heterocyclic radical; hydroxy-C1-C5alkyl; cyclohexyl optionally substituted with one or more C1,-C5alkyl; phenyl optionally substituted with a heterocyclic radical, aminocarbonyl or C1-C5alkylcarboxy; wenn n1 is 2, R3 is an alkylene-, cycloalkylene- or alkenylene radical which is optionally substituted by a carbonyl- or carboxy group; o R3 together with A forms a bivalent radical of the formula (Ia), wherein n2 is a number from 1 to 3; when n1 is 3, R3 is an alkanetriyl radical; wenn n1 is 4, R3 is an alkanetetrayl radical; A is -O-; or -N(R5)-; and R5 is hydrogen; C1-C5alkyl; or hydroxy-C1-C5alkyl. The compounds are useful as UV filters in sunscreen applications.

Journal ArticleDOI
TL;DR: This paper treated 4-aryl-2,4-dioxobutanoic acids with aromatic amines, 4-aminoantipyrine, and benzophenone hydrazone furnished N-substituted 2amino-4-aryl -4-oxo-2-butenoic acids.
Abstract: Treating 4-aryl-2,4-dioxobutanoic acids with aromatic amines, 4-aminoantipyrine, and benzophenone hydrazone furnished N-substituted 2-amino-4-aryl-4-oxo-2-butenoic acids that existed in solutions in enaminoketone and iminoketone forms. The acids obtained underwent in the presence of acetic anhydride cyclization into N-substituted 5-aryl-3-imino-3H-furan-2-ones.

Journal ArticleDOI
TL;DR: In this article, the benzophenone imine of glycine Wang resin with α,ω-dihaloalkanes yielded valuable reactive intermediates, such as racemic ω-chlorides, nitriles, and thioethers.

Journal ArticleDOI
TL;DR: An efficient synthesis of a C16 side chain benzophenone analogue of cryptophycin-24 using a crotylboration reaction and Heck coupling as key steps is described.

Journal ArticleDOI
TL;DR: In this article, the dilithio reagent was shown to react with various electrophiles (iodomethane, iodoethane, D2O, benzaldehyde, benzophenone, cyclohexanone) to give modified 3-substituted 1H-quinoxalin-2-ones in good yields.
Abstract: 3-Methyl-1H-quinoxalin-2-one has been doubly lithi­ated with n-butylithium at -78 °C in THF. The dilithio reagent thus obtained reacts with various electrophiles (iodomethane, iodoethane, D2O, benzaldehyde, benzophenone, cyclohexanone) to give modified 3-substituted 1H-quinoxalin-2-ones in good yields. In the reaction of the dilithio reagent with phenyl isothiocyanate the product was a tautomer of the simple substitution product. Reaction of the dilithio reagent with iodine gives an oxidatively dimerised product instead of the 3-iodomethyl derivative. Lithiations of 3-ethyl- and 3-propyl-1H-quinoxalin-2-ones, followed by reactions with representative electrophiles (benzaldehyde, benzophenone, cyclohexanone), behaved in a similar manner to give the corresponding modified 3-substituted derivatives in good yields.

Journal ArticleDOI
TL;DR: In this paper, S -(4-Benzoyl)phenylthiobenzoate (BpSBz) and BpOBz in acetonitrile were photolyzed under steady-state and laser-flash conditions.
Abstract: S -(4-Benzoyl)phenylthiobenzoate (BpSBz) and 4-benzoyl-phenyl benzoate (BpOBz) in acetonitrile were photolyzed under steady-state and laser-flash conditions. Analysis of transients absorptions and final products from the photolysis of BpSBz showed that 4-benzoylphenylthiyl and 4-benzoyl radicals were formed with an initial quantum yield of 0.45. Benzaldehyde was the main final product. In contrast, photolysis of BpOBz did not yield benzaldehyde, and nanosecond laser-flash photolysis of BpOBz showed only a long-lived triplet state. These results suggest that CO bond cleavage does not occur as a primary photochemical reaction of BpOBz. The implications for the use of BpSBz as a photoinitiator of polymerization are discussed.