Synthetic Application of PVP-stabilized Au Nanocluster Catalyst to Aerobic Oxidation of Alcohols in Aqueous Solution under Ambient Conditions

2007 ◽  
Vol 36 (2) ◽  
pp. 212-213 ◽  
Author(s):  
Hironori Tsunoyama ◽  
Tatsuya Tsukuda ◽  
Hidehiro Sakurai
Keyword(s):  
Aqueous Solution ◽  
Aerobic Oxidation ◽  
Ambient Conditions ◽  
Oxidation Of Alcohols ◽  
Synthetic Application

Study of aerobic oxidation of phenyl PtII complexes (dpms)PtIIPh(L) (dpms = di(2-pyridyl)methanesulfonate; L = water, methanol, or aniline)

2009 ◽  
Vol 87 (1) ◽  
pp. 110-120 ◽  
Author(s):  
Julia R Khusnutdinova ◽  
Peter Y Zavalij ◽  
Andrei N Vedernikov
Keyword(s):  
Aqueous Solution ◽  
Aerobic Oxidation ◽  
Reductive Elimination ◽  
High Yield ◽  
Ambient Conditions ◽  
Activation Barriers ◽  
Methanol Solutions ◽  
Anionic Species ◽  
Mechanism Of Oxidation ◽  
Solution Mechanism

Oxidation of phenyl PtII complexes K[(dpms)PtIIPh2], 1, (dpms)PtIIPh(MeOH), 2, (dpms)PtIIPh(OH2), 3, and methyl PtII complex (dpms)PtIIMe(NH2Ph), 6, with O2 in aqueous or methanol solutions under ambient conditions leads to corresponding (dpms)PtIVR(X)OH complexes (R = X = Ph, 7; R = Ph, X = OH, 8; R = Ph, X = OMe, 9; R = Me, X = NHPh; 11; dpms = di(2-pyridyl)methanesulfonate). Complexes 7–9 could be isolated in high yield. Complex 11 as well as its phenyl analogue (dpms)PtIVPh(NHPh)OH, 10 can be prepared in high yield by oxidation of corresponding (dpms)PtIIR(NH2Ph) with H2O2 in methanol. Phenyl PtII complexes (dpms)PtIIPh(HX) derived from HX = aniline and DMSO, 4 and 5, respectively, are inert toward O2. The rate of oxidation of 1–5 with O2 decreases in the order 1 > 3 ~ 2 » 4, and 5 is unreactive. Methyl analogues are significantly more reactive compared with their phenyl counterparts. Proposed mechanism of oxidation with O2 includes formation of anionic species (dpms)PtIIR(X)– responsible for reaction with dioxygen. Attempts at C–O and C–N reductive elimination from phenyl PtIV complexes 7–10 do not lead to phenyl derivatives PhX at 80–100 °C, consistent with the results of the DFT estimates of corresponding activation barriers, ΔG0 exceeding 28 kcal/mol.Key words: platinum phenyl complexes, oxidation, dioxygen, aqueous solution, mechanism.

scholarly journals A Bio-Inspired Lanthanum-Ortho Quinone Catalyst for Aerobic Oxidation of Alcohol

2020 ◽  
Author(s):  
Ruipu Zhang ◽  
Long Zhang ◽  
Ming-Tian Zhang ◽  
Sanzhong Luo
Keyword(s):  
Aerobic Oxidation ◽  
Earth Metal ◽  
Open Shell ◽  
Oxidation Catalysis ◽  
Oxidation Catalyst ◽  
Oxidation Reactions ◽  
Reductive Activation ◽  
Ambient Conditions ◽  
Semiquinone Radicals ◽  
Oxidation Of Alcohols

<p>Oxidation reactions are fundamental transformations in organic synthesis and chemical industry. With oxygen or air as terminal oxidant, aerobic oxidation catalysis provides the most sustainable and economic oxidation processes. Most aerobic oxidation catalysis employs redox metal as its active center. While nature provides non-redox metal strategy as in pyrroloquinoline quinone (PQQ)-dependent methanol dehydrogenases (MDH), such an effective chemical version is unknown. Inspired by the recently discovered rare earth metal-dependent enzyme Ln-MDH, here we show that an open-shell semi-quinone anionic radical species in complexing with lanthanum could serve as a very efficient aerobic oxidation catalyst under ambient conditions. In this catalyst, the lanthanum metal serves only as a Lewis acid promoter and the redox process occurs exclusively on the semiquinone ligand. The catalysis is initiated by 1e<sup>-</sup>-reduction of lanthanum-activated <i>ortho</i>-quinone to a semiquinone-lanthanum complex La(<b>SQ<sup>-.</sup></b>)<sub>2</sub>, which undergoes a coupled O-H/C-H dehydrogenation for aerobic oxidation of alcohols with up to 330 h<sup>-1</sup> TOF. This study suggests a possible functional mode of semiquinone radicals, widely observed with quinoproteins in Nature. Moreover, this unique reductive activation strategy as well as the resulted radical anion as redox ligand creates a new turning point in the development of efficient aerobic oxidation catalysis.</p>

scholarly journals A Bio-Inspired Lanthanum-Ortho Quinone Catalyst for Aerobic Oxidation of Alcohol

2020 ◽  
Author(s):  
Ruipu Zhang ◽  
Long Zhang ◽  
Ming-Tian Zhang ◽  
Sanzhong Luo
Keyword(s):  
Aerobic Oxidation ◽  
Earth Metal ◽  
Open Shell ◽  
Oxidation Catalysis ◽  
Oxidation Catalyst ◽  
Oxidation Reactions ◽  
Reductive Activation ◽  
Ambient Conditions ◽  
Semiquinone Radicals ◽  
Oxidation Of Alcohols

<p>Oxidation reactions are fundamental transformations in organic synthesis and chemical industry. With oxygen or air as terminal oxidant, aerobic oxidation catalysis provides the most sustainable and economic oxidation processes. Most aerobic oxidation catalysis employs redox metal as its active center. While nature provides non-redox metal strategy as in pyrroloquinoline quinone (PQQ)-dependent methanol dehydrogenases (MDH), such an effective chemical version is unknown. Inspired by the recently discovered rare earth metal-dependent enzyme Ln-MDH, here we show that an open-shell semi-quinone anionic radical species in complexing with lanthanum could serve as a very efficient aerobic oxidation catalyst under ambient conditions. In this catalyst, the lanthanum metal serves only as a Lewis acid promoter and the redox process occurs exclusively on the semiquinone ligand. The catalysis is initiated by 1e<sup>-</sup>-reduction of lanthanum-activated <i>ortho</i>-quinone to a semiquinone-lanthanum complex La(<b>SQ<sup>-.</sup></b>)<sub>2</sub>, which undergoes a coupled O-H/C-H dehydrogenation for aerobic oxidation of alcohols with up to 330 h<sup>-1</sup> TOF. This study suggests a possible functional mode of semiquinone radicals, widely observed with quinoproteins in Nature. Moreover, this unique reductive activation strategy as well as the resulted radical anion as redox ligand creates a new turning point in the development of efficient aerobic oxidation catalysis.</p>

Amphiphilic block copolymer-stabilized gold nanoparticles for aerobic oxidation of alcohols in aqueous solution

2008 ◽  
pp. 4442 ◽  
Author(s):  
Xueguang Wang ◽  
Hajime Kawanami ◽  
Nazrul M. Islam ◽  
Maya Chattergee ◽  
Toshirou Yokoyama ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Gold Nanoparticles ◽  
Block Copolymer ◽  
Aerobic Oxidation ◽  
Amphiphilic Block Copolymer ◽  
Oxidation Of Alcohols
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