Photocatalytic systems

Rehorek, Detlef; Salvetter, Jürgen; Hantschmann, Achim; Hennig, H.; Stasicka, Zofia; Chodkowska, Alina

doi:10.1016/s0020-1693(00)95476-8

Cited by 36 publications

(7 citation statements)

References 8 publications

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“…When investigating photoinduced chain reactions with 1 – 4 in the presence of alcohols, the oxidized cyanometallates formed in the course of photochemical IPCT excitation are of particular significance. Because these species absorb in the region of λ ≥350 nm, the irradiation wavelength has to be selected depending on both the absorption maximum of the IPCT transition and the spectroscopic behaviour of the oxidized cyanometallates, in order to exclude photoreactions of these species 22…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Chain Reactions of Alcohols in the Presence of Diphenyliodonium Ion Pairs with Cyanometallates—Steady State UV/Visible Spectroscopic and Pulse Radiolysis Studies

et al. 2001

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Diphenyliodonium ions (Ph2I+) form donor-acceptor ion pairs with suitable cyanometallates such as [Mo(CN)8]4-, [W(CN)8]4-, [Ru(CN)6]4- and [Os(CN)6]4-. Such ion pairs are characterized by new spectroscopic transitions due to second-sphere interactions between donor ([M(CN)x]4-, x=6, 8) and acceptor (Ph2I+) ions. Photochemical excitation of these ion-pair charge-transfer (IPCT) states leads to efficient electron transfer reactions that yield short-lived diphenyliodyl radicals (Ph2I*) and oxidized cyanometallates ([M(CN)x]3-). Diphenyliodyl radicals decay to iodobenzene and phenyl radicals. This very convenient source for generating phenyl radicals was applied to the photoinduced chain oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones, respectively. However, unexpected side reactions led to undesired chain-terminating reactions. Adduct formation of diphenyliodonium ions with alpha-hydroxyalkyl radicals was verified by pulse radiolysis studies. These relatively longlived adducts give rise to chain-terminating reactions because of interactions with [M(CN)x]4- complexes that lead to oxidized cyanometallates [M(CN)x]3- upon regeneration of the starting alcohols.

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Section: Resultsmentioning

confidence: 99%

Photoinduced Chain Reactions of Alcohols in the Presence of Diphenyliodonium Ion Pairs with Cyanometallates—Steady State UV/Visible Spectroscopic and Pulse Radiolysis Studies

et al. 2001

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“…5 3 -Co(CN) 5 3 " Co(dmg) 2 c Mo(CN) 7 2 " Fe(CO) 4 7 2~ forms rather stable spin adducts with both nitrosodurene and nitrosomesitylene even during irradiation (48). As shown by Alberti and Camaggi (61), nitro compounds may serve as efficient spin traps for manganese-centered radicals too.…”

Section: Spin Trapping Of Metal-centered Free Radicalsmentioning

confidence: 93%

“…SCHEME 4 Mo(CN) 8 3 " in methanol at -80°C we were able to detect a weak esr signal of a spin adduct to PBN (Û N ' = 1.46mT, a N 2 = 0.16mT, a H = 0.46mT). Based on the data given by Mao and Kevan (49), this spin adduct was originally attributed to -CN radical (48). However, it was shown by Janzen et al (44) that this assignment is obviously not correct.…”

Section: Trapping Of Atoms and Inorganic Radicalsmentioning

confidence: 97%

“…It is quite interesting that in CH 2 C1 2 instead of methanol, the -CN spin adduct to PBN (a N = 1.49 mT, a H = 0.20 mT) can be readily observed during the photolysis of Mo-(CN) 8 3 ". In methanol, OCH 3 radicals are the major oxidation product (48). Other important intermediates during the photolysis of metal complexes are known to be hydroxyl, -OH, and superoxide, -O 2~, radicals, respectively.…”

Section: Trapping Of Atoms and Inorganic Radicalsmentioning

confidence: 99%

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Spin trapping in photochemistry of coordination compounds

Rehorek¹,

Hennig²

1982

Can. J. Chem.

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DETLEF REHOREK and HORST HENNIG. Can. J. Chem. 60, 1565Chem. 60, (1982.The application of spin-trapping technique to detect short-lived paramagnetic species formed during photochemical reactions of coordination compounds is reviewed. Interference of radical recombinations by scavenging action of spin traps has been pointed out to be important at high spin-trap concentrations only. Due to only a limited extent of side reactions, nitrosodurene and phenyl N-/

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“…C Cyano-bridged bimetallic assemblies are classified as class II mixed-valence compounds. [1][2][3][4][5][6][7][8][9][10][11] Photo-induced charge transfer is expected for class II mixed-valence compounds, which possess deep colors due to the valency mixing. Among such compounds, special attention has been paid to cyano-bridged CuMo bimetal assemblies owing to their photomagnetism and ferroelectrics.…”

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confidence: 99%

Room-temperature thermally induced relaxation effect in a two-dimensional cyano-bridged Cu-Mo bimetal assembly and thermodynamic analysis of the relaxation process

et al. 2013

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We observed a photo-switching effect in [CuII(1,4,8,11-tetraazacyclodecane)]2[MoIV(CN)8]·10H2O by irradiation with 410-nm light around room temperature using infrared spectroscopy. This photo-switching is caused by the photo-induced charge transfer from MoIV to CuII. The photo-induced phase thermally relaxed to the initial phase with a half-life time of 2.7 × 101, 6.9 ×101, and 1.7 × 102 s at 293, 283, and 273 K, respectively. The relaxation process was analyzedusing Hauser's equation, k =k0exp[−(Ea +Ea*γ) /kBT], where k is the rate constant of relaxation, k0 is the frequency factor, Eais the activation energy,Ea* is the additional activation energy due to the cooperativity,and γ is the fraction of the photo-induced phase. k0, Ea, and Ea* were evaluated as 1.28 × 107 ± 2.6 s−1, 4002 ± 188 cm−1, and 546 ± 318 cm−1, respectively. The value of Ea is much larger than that of the relaxation process for the typical light-induced spin crossover effect (Ea ≈1000 cm−1). Room-temperature photo-switching is an important issue in the field of optical functional materials. The present system is useful for the demonstration of high-temperature photo-switching material.

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Photocatalytic systems

Cited by 36 publications

References 8 publications

Photoinduced Chain Reactions of Alcohols in the Presence of Diphenyliodonium Ion Pairs with Cyanometallates—Steady State UV/Visible Spectroscopic and Pulse Radiolysis Studies

Photoinduced Chain Reactions of Alcohols in the Presence of Diphenyliodonium Ion Pairs with Cyanometallates—Steady State UV/Visible Spectroscopic and Pulse Radiolysis Studies

Spin trapping in photochemistry of coordination compounds

Room-temperature thermally induced relaxation effect in a two-dimensional cyano-bridged Cu-Mo bimetal assembly and thermodynamic analysis of the relaxation process

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