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Search for "photocatalyst" in Full Text gives 136 result(s) in Beilstein Journal of Organic Chemistry.
Recent advances in transition metal-catalyzed Csp2-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation
Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287
- iodide and generate the corresponding radical (Scheme 13). Titanium dioxide was used as heterogeneous photocatalyst in the perfluoroalkylation of α-methylstyrene with perfluorohexyl iodide by M. Yoshida et al. [120]. While the main product arose from the formal perfluoroalkylation of a methyl sp3-C–H
The chemistry of amine radical cations produced by visible light photoredox catalysis
Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234
- ). Therefore, a photocatalyst is often required to initialize electron-transfer reactions with amines. Some of the frequently used photocatalysts include ruthenium [24][25][26] and iridium [27][28] polypyridyl complexes as well as organic dyes [29][30] that are absorbed in the visible-light region. They all
- approach to exploit synthetic utility of photogenically produced amine radical cations. Reductive quenching of the photoexcited state of a photocatalyst (M) by amine 1 is governed by the reduction potentials of the photoexcited state and the amine (Scheme 1). The amine’s reduction potential, which can be
- 5 W blue LED as the light source. N-arylglycine derivatives 65, including esters and ketones, were successfully converted to the products 67. Rueping used Ir(ppy)2(bpy)PF6 as the photocatalyst, air, and an 11 W fluorescent bulb as the light source. Additionally, Zn(OAc)2 was employed as a Lewis acid
Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review
Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146
- medium-band-gap semiconductor and has proved to be an efficient photocatalyst for synthetic purposes [66][67]. It has been demonstrated that the excited state of g-C3N4, obtained by irradiation with visible light, is able to activate O2 to the corresponding superoxide radical. The latter could undergo
New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators
Beilstein J. Org. Chem. 2013, 9, 877–890, doi:10.3762/bjoc.9.101
- ). There is also an usual cationic polymerization (CP; r3 in Scheme 1) [1][2]. When the PIs exhibit a catalytic behavior analogous to a photocatalyst (PC) in organic chemistry, they are designed as photoinitiator catalysts (PIC). PIs as well as PICs are based on pure organic, that is, metal free, or
- both Rp and conv are better when comparing to Py_3/MDEA. Photocatalyst behavior of the Co_Pys The photocatalytic behavior of the Co_Pys is investigated in the most interesting compounds reported above for the photopolymerization reactions. The steady-state photolysis of Py_3/PBr, Py_3/Iod, Py_3/MDEA
- shows that the photolysis is faster with Py_11/Iod than with Py_11/Iod/NVK couples (Figure 11A versus Figure 11B). This difference highlights that in the presence of NVK, Py_11 is regenerated according to an oxidation cycle (Scheme 6). Therefore, Py_11 behaves as a new photocatalyst in agreement with
NHC-catalysed highly selective aerobic oxidation of nonactivated aldehydes
Beilstein J. Org. Chem. 2013, 9, 602–607, doi:10.3762/bjoc.9.65
- of carbinols to aldehydes or ketones using oxygen, visible light and mesoporous graphitic carbon nitride (mpg-C3N4) polymer as a metal-free photocatalyst [4]. As an extension of this method we were interested in a consecutive organocatalytic process using an N-heterocyclic carbene (NHC) together with
Flow photochemistry: Old light through new windows
Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229
- issues such as oxygen depletion in the reaction mixture during the reaction, and bubble formation. Such reactors have been shown to be effective in the oxidative degradations of para-chlorophenol, toluene [36], phenol and methylene blue [37] with a deposited TiO2 photocatalyst. Aside from oxidative
- efficient irradiation of the whole reaction media; this is especially useful if the photocatalyst is solid supported. The immobilised catalyst of choice is titanium dioxide, both with and without Pt doping, due to its photochemical stability. The photocatalyst can be effectively deposited onto a
- synthetic use of titanium dioxide as a photocatalyst is in the alkylation of amines. As shown in Scheme 10, photolysis of a mixture of benzylamine (28) and ethanol in the presence of a titanium dioxide photocatalyst gave the ethylamine 29 in high conversion, employing both the oxidative (ethanol to
Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines
Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41
- -harvesting materials [36][42][45][46][47][51][52], as chemosensors [37], in supramolecular assemblies [38][39][44], as a photocatalyst for H2 generation [40][53] or for the preparation of hybrid materials, such as functionalised polyoxometalates as depicted in Figure 3 [41]. Utilization of furanyl
Microphotochemistry: 4,4'-Dimethoxybenzophenone mediated photodecarboxylation reactions involving phthalimides
Beilstein J. Org. Chem. 2011, 7, 1055–1063, doi:10.3762/bjoc.7.121
- application of LEDs [37]. We have therefore investigated the usage of 4,4’-dimethoxybenzophenone (DMBP) as a photocatalyst that absorbs readily in the UVA region. In this publication we present preliminary results of five DMBP mediated model transformations (Scheme 1). All reactions were previously studied
Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties
Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26
- larger (Table 1, entries 1+2) in comparison to the ammonium salt 8 (entry 3). In water, however, the accelerating effect is not observed (entries 5–8). The presence of the photocatalyst is essential in all cases, as the non-catalyzed hydrolysis is slow under the reaction conditions (<5% conversion). In
- with blue light the yield after 8 h reaction time increased further (entry 2) and was significantly higher as in the absence of a photocatalyst (entry 5). However, a comparison with tetraacetyl riboflavin (3) under identical reaction conditions showed an even more pronounced acceleration of the
Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions
Beilstein J. Org. Chem. 2009, 5, No. 24, doi:10.3762/bjoc.5.24
- photocatalyst with a band gap of 3.2 eV corresponding to a wavelength of 387 nm [14]. Thus, we attempted to evaluate titanium dioxide as a potential TOP type catalyst based on the excellent work of Taylor and co-workers [15][16] by examining its behaviour under various energy sources (Table 1). Titanium dioxide
Photosonochemical catalytic ring opening of α-epoxyketones
Beilstein J. Org. Chem. 2007, 3, No. 2, doi:10.1186/1860-5397-3-2
- -2,4,6-triphenylpyridinium tetrafluoroborate (NBTPT) as photocatalyst in methanol. Sonication of these compounds in the presence of NBTPT did not result in the opening of epoxide ring, but the use of ultrasound increased the rate of photoreaction. Background The advantages of ultrasound-assisted
- the corresponding γ-lactone. [19] In our recent study, we have used 1-benzyl-2,4,6-triphenylpyridinium tetrafluoroborate (NBTPT) as photocatalyst in a highly diastereoselective ring opening of α-epoxyketones in acetone solution with the formation of 1.3-dioxolanes. [20] Ring opening of epoxides and α
- carbonyl compounds [43][44][45][46][47][48][49][50] or by nucleophilic attack of appropriate reagents. [36][39][51] Recently, we have reported on the photocatalytic ring opening of α-epoxyketones 1a-f and 2,4,6-triphenylpyrilium tetrafluoroborate (TPT) as photocatalyst in methanol, [37] cyclohexanone, [38
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