Mechanism of (μ-H)(μ-alkenyl)Re2(CO)8 Formation in 350 nm Flash Irradiations of Re2(CO)10

Sarakha, Mohamed; Cozzi, M.; Ferraudi, G.

doi:10.1021/ic951483o

Cited by 16 publications

(20 citation statements)

References 15 publications

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“…In these experiments, 20 ns flashes of 351 nm light were generated with a Lambda Physik SLL-200 excimer laser. 12, 13 Solutions for the photochemical work were deaerated with streams of ultrahigh purity N 2 before and during the irradiations. A flow-stop system ensured that fresh solution was introduced into the reaction cell in experiments where the photodecomposition of the complexes and/or formation of products interfered with the optical measurements.…”

Section: Flash Photochemical Experimentsmentioning

confidence: 99%

Temperature effects on the quenching of the 5D0→7F2 emission of Eu(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)3 by a Cu(ii) macrocycle

Wolcan

Villata

Capparelli

et al. 2004

Photochem Photobiol Sci

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Luminescence quenching of Eu(fod)3(fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) by a Cu(II) macrocycle was studied at 25, 35 and 45 degrees C by steady-state and flash luminescence techniques, varying the Cu(II) concentration between 0.2 and 20 mM. Experimental variation of the observed rate constant with the quencher concentration is rationalized in terms of a mechanism involving the quenching of two unequilibrated species by the Cu(II) macrocycle.

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Section: Flash Photochemical Experimentsmentioning

confidence: 99%

Temperature effects on the quenching of the 5D0→7F2 emission of Eu(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)3 by a Cu(ii) macrocycle

Wolcan

Villata

Capparelli

et al. 2004

Photochem Photobiol Sci

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“…Experimentally, neither of these two experiments revealed an inverse secondary KIE: the former gave a KIE of 1.39 and the later experiment gave KIE of 1.01. While rhenium carbonyl complexes are known to be able to cleave vinyl C–H bonds, the lack of a large primary KIE (>3) in any of the reactions in Scheme with deuterated analogs of 1-octene rule out any C–H bond breaking events occurring on the alkene at C1-, C2-, and C3-positions in the turnover-limiting step; these results are consistent with mechanisms shown in Scheme B.…”

Section: Kinetic Isotope Effect and Deuterium Labelling Studiesmentioning

confidence: 85%

“…Using 3,3- d 2 -oct-1-ene (3,3- d 2 - 2 ) in the reaction provided exclusively 3,3- d 2 - 3 . All of these observations are consistent with a reaction pathway that does not involve reversible cleavage of the allylic C–D bonds (e.g., Re−π-allyl complex) or the vinyl C–D bonds . The observations shown in Scheme are consistent with an irreversible hydrometalation process.…”

Section: Kinetic Isotope Effect and Deuterium Labelling Studiesmentioning

confidence: 88%

Mechanistic Study of a Re-Catalyzed Monoalkylation of Phenols

et al. 2018

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A mechanistic study of a rhenium catalyzed monoalkylation of phenols is described. Reaction kinetics reveals a zero-order dependence on both alkene and phenol and a half order dependence on catalyst. Isotopic labeling studies, competition experiments, kinetic isotope effects, and Hammett analysis together afford experimental data consistent with a reversible C–H activation step and an irreversible hydrometalation process. The turnover-limiting step is identified as catalyst deaggregation. NMR studies of binary mixtures of catalyst and a single substrate (alkene or phenol) as well as those of reaction mixtures identify potential intermediates and off-cycle species. Despite the numerous Re complexes formed in these mixtures, the overall reaction is both high yielding and highly selective for monoalkylation of phenols.

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“…In this experiment, potential modulation was between E À 1.86 V and E ref À 1.16 V, i.e., DOD % DR/R [R À1.86 -R À1.16 ]/R À1. 16 . The spectrum in Fig.…”

Section: A Potential Modulation Betweenmentioning

confidence: 99%

Shielding of Electron Acceptors Coordinated to Rhenium(I) by Carboxylato Groups. Intraligand and Charge-Transfer Excited-State Properties of fac-(‘Anthraquinone-2-carboxylato')(2,2′-bipyridine)tricarbonylrhenium (fac-[ReI(aq-2-CO2)(2,2′-bipy)(CO)3])

Ruiz

Juliarena

Lezna

et al. 2002

HCA

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The photophysical and photochemical properties of (OC-6-33)-(2,2'-bipyridine-kN 1 ,kN 1 ')tricarbonyl(9,10-dihydro-9,10-dioxoanthracene-2-carboxylato-kO)rhenium (fac-[Re I (aq-2-CO 2 )(2,2'-bipy)(CO) 3 ]) were investigated and compared to those of the free ligand 9,10-dihydro-9,10-dioxoanthracene-2-carboxylate ( anthraquinone-2-carboxylate) and other carboxylato complexes containing the (2,2'-bipyridine)tricarbonylrhenium ([Re(2,2'-bipy)(CO) 3 ]) moiety. Flash and steady-state irradiations of the anthraquinone-derived ligand (l exc 337 or 351 nm) and of its complex reveal that the photophysics of the latter is dominated by processes initiated in the Re-to-(2,2'-bipyridine) charge-transfer excited state and 2,2'-bipyridine-and (anthraquinone-2-carboxylato)-centered intraligand excited states. In the reductive quenching by N,Ndiethylethanamine (TEA) or 2,2',2''-nitrilotris[ethanol] TEOA, the reactive states are the 2,2'-bipyridinecentered and/or the charge-transfer excited states. The species with a reduced anthraquinone moiety is formed by the following intramolecular electron transfer, after the redox quenching of the excited state:The photophysics, particularly the absence of a Re I -to-anthraquinone charge-transfer excited state photochemistry, is discussed in terms of the electrochemical and photochemical results.Introduction. ± The substitution of a halide ligand X by the spectator ligand L S in [Re I XL A (CO) 3 ], where L A is a bis(monodentated azine) or a bidentate azine 1 ), has provided useful procedures for the preparation of related [Re I L S L A (CO) 3 ] complexes [1 ± 7]. Interest in the properties that L S imposes on the ÀRe I L A (CO) 3 moiety is brought about by possible applications of the Re complexes to biochemical processes [8 ± 11] and to CO 2 reduction [12]. Also, the derivatization of polymers with chromophores, e.g., with pendant ÀRe I L A (CO) 3 groups [13] has prompted investigation of the role of L S in the reactivity of some Re I monomers [14]. Literature reports show, for example, that the function of L S is to exert small perturbations that alter the electronic structure of the chromophore and modify its photophysics [6]. In the other extreme of a strong electronic interaction between L S and the Re I chromophore, the spectator ligand can participate in redox processes similar to those of L A . Indeed, competitive electron transfer to L A and L S has been observed in the ground and excited

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Mechanism of (μ-H)(μ-alkenyl)Re₂(CO)₈ Formation in 350 nm Flash Irradiations of Re₂(CO)₁₀

Cited by 16 publications

References 15 publications

Temperature effects on the quenching of the 5D0→7F2 emission of Eu(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)3 by a Cu(ii) macrocycle

Temperature effects on the quenching of the 5D0→7F2 emission of Eu(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)3 by a Cu(ii) macrocycle

Mechanistic Study of a Re-Catalyzed Monoalkylation of Phenols

Shielding of Electron Acceptors Coordinated to Rhenium(I) by Carboxylato Groups. Intraligand and Charge-Transfer Excited-State Properties of fac-(‘Anthraquinone-2-carboxylato')(2,2′-bipyridine)tricarbonylrhenium (fac-[ReI(aq-2-CO2)(2,2′-bipy)(CO)3])

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