Adamantane Selective Hydroxylation by 2,6-Dichloropyridine N-Oxide and Organoruthenium(II) Polyoxometalates as Catalyst Precursors

Bonchio, Marcella; Scorrano, Gianfranco; Toniolo, P.; Proust, Anna; Artero, Vincent; Conte, Valeria

doi:10.1002/1615-4169(200209)344:8<841::aid-adsc841>3.0.co;2-l

Cited by 35 publications

(15 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ruthenium porphyrins and related complexes have received considerable attention because of the close periodic relationship to the biologically significant iron and the rich coordination and redox chemistry of ruthenium, which spans oxidation states from +2 to +7 in the porphyrin ligand environment. [5][6][7][8][9][10][11][12][13][14][15][16][17] Notably, ruthenium porphyrins have been shown to utilize dioxygen in air for the clean epoxidation of olefins under mild conditions, 18 and they have also shown promise in the activation of nitrous oxide. [19][20][21][22][23] The mechanism of aerobic epoxidation mediated by ruthenium porphyrins has been examined, and a trans-dioxoruthenium(VI) complex was found to be the active oxidant.…”

Section: Introductionmentioning

confidence: 99%

Fast Catalytic Hydroxylation of Hydrocarbons with Ruthenium Porphyrins

et al. 2006

Self Cite

View full text Add to dashboard Cite

Ruthenium porphyrin complexes such as carbonylruthenium(II) tetrakispentafluorophenylporphyrin [Ru(II)(TPFPP)(CO)] were found to be efficient catalysts for the hydroxylation of alkanes in the presence of 2,6-dichloropyridine N-oxide as the oxidant under mild, nonacidic conditions. Up to 14 800 turnovers (TO) and rates of 800 TO/min were obtained for the hydroxylation of adamantane. The hydroxylation of cis-decalin afforded cis-9-decalol and cis-decalin-9,10-diol, exclusively, thus, excluding a long-lived radicals mechanism. The kinetics of product evolution in a typical catalytic oxygenation showed an initial induction period followed by a fast, apparently zero-order phase with maximum rates and high efficiencies. Deuterium isotope effects (kH/kD) in the range of 4.2-6.4 were found for the hydroxylation of alkanes. A Hammett treatment of the data for the oxidation of para-substituted toluene derivatives showed a linear correlation with a highly negative rho+ value of -2.0. On the basis of kinetic and spectroscopic evidence, Ru(VI)(TPFPP)(O)2, Ru(II)(TPFPP)(CO), and Ru(IV)(TPFPP)Cl2 observed during catalysis were ruled out as candidates for the active catalyst responsible for the high efficiencies and turnover rates in the oxidation reactions. The fastest rates of adamantane hydroxylation with 2,6-dichloropyridine N-oxide were achieved by the reductive activation of Ru(IV)(TPFPP)Cl2 with a zinc amalgam. This redox activation is consistent with the formation of an active Ru(III) intermediate in situ by a one-electron reduction of the Ru(IV) porphyrin. EPR spectra characteristic of Ru(III) have been observed upon the reduction of Ru(IV)(TPFPP)Cl2 with a zinc amalgam. In the adamantane oxidation mediated with Ru(III)(TPFPP)(OEt), it was found that, during this process, the Ru(III) porphyrin was gradually converted to a dioxoRu(VI) porphyrin. Concomitant with this conversion, the reaction rates decreased. Catalyst activation was also stimulated by autoxidation of the solvent CH2Cl2. On the basis of these data, a mechanism is proposed that incorporates a "fast" cycle involving metastable Ru(III) and oxoRu(V) intermediates and a "slow" oxidation cycle, mediated by oxoRu(IV) and trans-dioxoRu(VI) porphyrin complexes.

show abstract

Section: Introductionmentioning

confidence: 99%

Fast Catalytic Hydroxylation of Hydrocarbons with Ruthenium Porphyrins

et al. 2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…56 In addition, appropriate synthetic strategies can be exploited to insert one or more redox active metal centers within a totally inorganic ligand system provided by the POM framework. 57,58 POM-based ligands feature a rigid polydentate binding site with unique electron-and proton-acceptor ability, 59 and interesting structural and coordination properties. 6,60 In particular, Keggin-type undecatungstates of formula [XW 11 O 39 ] n-(X = B, Si, Ge, P, As), exhibiting a planar tetradentate coordination geometry with a proximal axial position, have been considered as the inorganic porphyrin analogues.…”

Section: Selective Oxidation In Water: the Ligand Strategymentioning

confidence: 99%

Catalytic Strategies for Sustainable Oxidations in Water

Carraro¹,

Sartorel²,

Scorrano³

et al. 2008

Synthesis

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, we expected that catalysts prepared from hybrid clusters would comprise a high density of metal/oxide interfaces. Although hybrid clusters have great potential in such applications, there have been few reports on their use in heterogeneous catalysts. , …”

Section: Introductionmentioning

confidence: 99%

“…Although hybrid clusters have great potential in such applications, there have been few reports on their use in heterogeneous catalysts. 19,20 We selected the N-alkylation of amines with alcohols as the test reaction. This reaction is regarded as an environmentally friendly method for C−N bond formation because as alkylating agents, alcohols produce water as the only byproduct.…”

mentioning

confidence: 99%

High-Density Formation of Metal/Oxide Interfacial Catalytic Active Sites through Hybrid Clustering

Hayashi

Shishido

2021

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

We developed a method for preparing catalysts based on hybrid clusters that formed high-density metal/oxide interfacial active sites. A Ru–V hybrid cluster, [{Ru(cym)}4V6O19] (cym = p-cymene), was used as a precursor to prepare Ru–V catalysts. Transmission electron microscopy and X-ray absorption spectroscopy (XAS) analyses revealed that composite nanoparticles of Ru and V were formed through hybrid clustering, while conventional coimpregnation of Ru and V afforded separate nanoparticles. The activity of the Ru–V catalysts toward N-alkylation of amines with alcohols depended on the mixing method (hybrid clustering > coimpregnation > physical mixing ≈ pristine Ru). The formation mechanism of the composite nanoparticles from the hybrid cluster was revealed using in situ XAS analysis. Finally, we proposed a simple but efficient catalyst preparation method, based on in situ formation of hybrid cluster precursors combined with a conventional coimpregnation method.

show abstract

Adamantane Selective Hydroxylation by 2,6-Dichloropyridine N-Oxide and Organoruthenium(II) Polyoxometalates as Catalyst Precursors

Cited by 35 publications

References 9 publications

Fast Catalytic Hydroxylation of Hydrocarbons with Ruthenium Porphyrins

Fast Catalytic Hydroxylation of Hydrocarbons with Ruthenium Porphyrins

Catalytic Strategies for Sustainable Oxidations in Water

High-Density Formation of Metal/Oxide Interfacial Catalytic Active Sites through Hybrid Clustering

Contact Info

Product

Resources

About