Oxygen Transfer Reagent Research Articles

Synthesis and Full Characterization of Molybdenum and Antimony Corroles and Utilization of the Latter Complexes as Very Efficient Catalysts for Highly Selective Aerobic Oxygenation Reactions

Two molybdenum and three antimony corroles were isolated and characterized by NMR, EPR, and electrochemistry. The very negative reduction potentials of the (oxo)molybdenum(V) corroles are clearly related to their inactivity as oxygen transfer reagents and the unsuccessful attempts to isolate lower-valent molybdenum corroles. X-ray crystallography of the (oxo)molybdenum(V) corrole 1a and the trans-difluoroantimony(V) corrole 2c, the first of their kind, revealed that their molecular structures represent extreme cases of such complexes: a highly domed corrole with very large out-of-plane metal displacement for 1a (0.73 Angstroms) and a very flat corrole with the metal ion in its center for 2c. All three antimony corroles displayed high activity and selectivity as catalysts for the photoinduced oxidation of thioanisole by molecular oxygen, with superior results obtained in alcoholic solvents with 2c as catalyst. Allylic and tertiary benzylic CH bonds were also oxidized under those conditions, with absolute selectivity to the corresponding hydroperoxides.

Theoretical study on the reaction of the [formula omitted] ground state of ScS + with oxygen-transfer reagent: ScS + + CO 2 → ScO + + COS in the gas phase

The reaction mechanisms of the title reaction have been studied by using density functional theory (DFT) and Møller–Plesset perturbation theory (MP2). It is found that the reaction proceeds via two four-center transition states (TS1 and TS2) with a cyclic complex ( b) locating between them on the reaction potential surface. The activation barriers of the two transition states are both negatively valued by −8.6 and −2.6 kcal/mol, respectively, at B3LYP/6-311+G * level. Another reaction channel: ScS + + CO 2 → ScOS + + CO was also investigated and its activation barrier is much higher (50.2 kcal/mol) which is in line with the experimental observation.

Theoretical study on the reaction of the ground state of YS+ with oxygen-transfer reagent: YS++CO2→YO++COS in the gas phase

The reaction mechanisms of the 1Σ+ ground state of YS+ with oxygen-transfer reagent: YS+ + CO2 → YO+ + COS in the gas phase has been studied by using density functional theory (DFT). It is found that the reaction proceeds via two four-center transition states (TS1 and TS2) with a cyclic complex (b) locating between them on the reaction potential surface. The activation barriers of the two transition state are −8.3 and 2.1 kcal/mol, respectively, at B3LYP/6-31+G* level plus ZPE relative to the reactants. The second reaction step via transition state TS2 should be the rate-determining reaction step. The similarities and differences between YS+ and ScS+ for this type reaction were also discussed.

Methyltrioxorhenium (MTO)

Methyltrioxorhenium (1) is an important and versatile catalyst widely studied as an oxygen transfer reagent in oxidation reactions of a variety of substrates. [1] The important features of MTO as a catalyst are its ease of synthesis, commercial availability and stability to air. MTO was firstly synthesized by Beattie and Jones in 1979. [2] Sub­sequently, Herrmann et al. developed a more simple and ­efficient synthesis based on the reaction of dirhenium ­heptoxide with methyltributyltin. [3]

On the way to a new class of catalysts--high-valent transition-metal complexes that catalyze reductions.

Surprise! Owing to its rhenium(V) center, which bears two terminal oxo ligands, [ReI(O)2(PPh3)2] appears at first glance to be an oxygen-transfer reagent. The complex is, however, a novel catalyst for a reduction: the hydrosilylation of aldehydes and ketones (see scheme).

Theoretical study on the reaction of the ground state 2Δ of TiS + with oxygen-transfer reagent: TiS ++H 2O→TiO ++H 2S in the gas phase

The reaction mechanism of the ground state 2Δ of TiS + with oxygen-transfer reagent: TiS ++H 2O→TiO ++H 2S in the gas phase has been proposed and investigated by ab initio methods with 6-31G** basis set for non-metal atoms and the effective core potentials of Lanl2dz for Ti. The reaction is proceeding via two steps with seven stationary points (reactants, three intermediate complexes: ( a), ( b) and ( c) two transition states: TS1 and TS2, and products) on the reaction potential surface which involved two 1,3-hydrogen shift reactions from oxygen atom to sulfur atom via a four-center transition state. The activation barriers of the two transition states are −54.0 and −65.1 kcal/mol, respectively, at MP4 (SDTQ)/6-31G**//MP2/6-31G** level plus zero-point energy relative to the reactants, which indicates that cationic titanium sulfide is favorable to this type of reaction and the collision rate of the reactants forming the complex ( a) should be the main factor that determines the reaction rate.

Theoretical study on the reaction of the 1Σ + ground state of LaS + with oxygen-transfer reagent: LaS ++COS→LaO ++CS 2 in the gas phase

The reaction mechanisms of the 1Σ + ground state of LaS + with oxygen-transfer reagent: LaS ++COS→LaO ++CS 2 in the gas phase has been studied by ab initio methods. It is found that the reaction proceeds via two four-center transition states ( TS1 and TS2) with a cyclic complex ( b) locating between them on the reaction potential surface. The activation barriers of the two transition state are 3.4 kcal/mol at MP4 (SDTQ)/6-31+G*//MP2/6-31+G* level plus ZPE relative to the reactants. The similarities and differences among ScS +, YS + and LaS + for this type reaction were also discussed.

Theoretical study on the reaction of the [formula omitted] ground state of ScS + with oxygen-transfer reagent: ScS ++COS→ScO ++CS 2 in the gas phase

The reaction mechanisms of the 1 Σ + ground state of ScS + with oxygen-transfer reagent: ScS ++COS→ScO ++CS 2 in the gas phase has been studied by using ab initio methods. It is found that the reaction proceeds via two four-center transition states ( TS1 and TS2) with a cyclic complex ( b) located between them on the reaction potential surface. The first reaction step proceeding via TS1 is rate limiting and the activation barriers are 31.5 and 6.4 kcal/mol at MP4 (SDTQ)/6-31+G*//MP2/6-31+G* level plus ZPE, relative to the intermediate complex ( a) and the reactants, respectively.

Theoretical study on the reaction of the ground state 1Σ + of YS + with oxygen-transfer reagent: YS ++COS→YO ++CS 2 in the gas phase

The reaction mechanisms of the ground state 1Σ + of YS + with oxygen-transfer reagent: YS ++COS→YO ++CS 2 in the gas phase has been studied by ab initio methods. It is found that the reaction proceeds via two four-center transition states (TS1 and TS2) with a cyclic complex ( b) locating between them on the reaction potential surface. The activation barriers of the two transition state are both negatively valued by −7.6 kcal/mol at MP4 (SDTQ)/6-31+G*//MP2/6-31+G* level plus ZPE relative to the reactants. The collision rate coefficient of the reactants should be the main factor limiting the reaction rate. The similarities and differences between YS + and ScS + for this type reaction were also discussed.

Theoretical study on the reaction of the ground state [formula omitted] of LaS + with oxygen-transfer reagent: LaS ++H 2O→LaO ++H 2S in the gas phase

The reaction mechanism of the ground state 1Σ + of LaS + with oxygen-transfer reagent: LaS ++H 2O→LaO ++H 2S in the gas phase has been proposed and investigated by ab initio methods. The reaction is proceeding via two 1,3-hydrogen-shift reactions from oxygen atom to sulfur atom (via TS1 and TS2). The activation energies of two steps are 20.8 and 29.5 kcal/mol, respectively, at MP4 (SDTQ)/6- 31 G ∗∗ //MP2/6- 31 G ∗∗ level plus zero-point energy relative to their corresponding intermediate reactants. But TS1 locates higher in energy that TS2 by only 1.8 kcal/mol on the reaction path. The periodic trends of Sc, Y and La for this type of reaction were also discussed.

Theoretical study on the reaction of the ground state 1Σ + of ScS + with oxygen-transfer reagent: ScS ++H 2O→ScO ++H 2S in the gas phase

The reaction mechanism of the ground state 1Σ + of ScS + with oxygen-transfer reagent: ScS ++H 2O→ScO ++H 2S in the gas phase has been proposed and investigated by ab initio methods with 6-31G ∗∗ basis set for non-metal atoms and the ECPs of Lan12dz for Sc. The reaction is proceeding via two steps with seven stationary points (reactants, three intermediate complexes: ( I), ( II) and ( III), two transition states: TS1 and TS2, and products) on the reaction potential surface which involved two 1,3-hydrogen-shift reactions from oxygen atom to sulfur atom via a four-center transition state, respectively. The activation energies of the two steps are 25.3 and 30.2 kcal mol −1, respectively, at MP4 (SDTQ)/6-31G ∗∗//MP2/6-31G ∗∗ level plus zero-point energy, which indicates that the second reaction step is the rate-determining step and the theoretical rate constants based on the transition state theory (TST) with Wigner and Eckart tunneling correction are 2.45 and 42.02 (in 10 −10 s −1), respectively, for the forward reaction and 0.003 and 0.048 (in 10 −10 s −1) for the reverse reaction.

Theoretical study on the reaction of the ground state 1Σ + of YS + with oxygen-transfer reagent: YS ++H 2O→YO ++H 2S in the gas phase

The reaction mechanism of the ground state 1Σ + of YS + with oxygen-transfer reagent: YS ++H 2O→YO ++H 2S in the gas phase has been proposed and investigated by ab initio methods with 6-31G ∗∗ basis set for non-metal atoms and the effective core potentials of Lanl2dz for Y. The reaction is proceeding via two steps with seven stationary points (reactants, three intermediate complexes: ( a), ( b) and ( c), two transition states: TS1 and TS2, and products) on the reaction potential surface which involved two 1,3-hydrogen-shift reactions from oxygen atom to sulfur atom via a four-center transition state, respectively. The activation energies of the two steps are 14.2 and 47.0 kcal mol −1, respectively, at MP4 (SDTQ)/6-31G ∗∗//MP2/6-31G ∗∗ level plus zero-point energy, which indicates that the second reaction step is the rate-determining step.

Sulfate radical anions (SO(4)(*)(-)) as donor of atomic oxygen in anionic transannular, self-terminating, oxidative radical cyclizations

SO(4)(*)(-) generated by the Fenton redox system S(2)O(8)(2)(-)- Fe(2+) induces a novel anionic, transannular, self-terminating, oxidative radical cyclization in the reactions with the ten-membered cycloalkyne 1 and the cycloalkynone 7, yielding the bicyclic ketones 5 and 6 or the alpha,beta-epoxy ketones 8 and 9, respectively. In these reactions SO(4)(*)(-) acts as an oxygen transfer reagent and can thus be considered as a donor of atomic oxygen in solution.

Substituted metal carbonyls: [{{(p-MeOC6H4)2Te}M(CO)4}]2 (M = Mn or Re) in the presence of an O-atom transfer reagent

Two novel telluroether-disubstituted metal carbonyls, [(R2Te)M(CO)4]2(M = Mn or Re; R = p-MeOC6H4), were prepared from [M2(CO)10] by an oxygen atom transfer. The axial CO is replaced by the telluroether when [M2(CO)10] reacts with a new kind of oxygen transfer reagent, R2TeO, under mild conditions. The products were characterized by elemental analysis, i.r., 1H- and 13C-n.m.r., and FAB-mass spectra. The configuration of the substituted carbonyl is unique, i.e. the 1, l′-diax isomer.

Oxidation of Thioether Ligands in Pseudotetrahedral Cyclopentadienylruthenium Complexes: Toward a New Stereoselective Synthesis of Chiral Sulfoxides(1).

Ionic ruthenium thioether complexes [Cp(LL')Ru(SRR')]PF(6) (LL' = Ph(2)PCH(2)PPh(2) (1), Ph(2)PC(2)H(4)PPh(2) (2), (Ph(3)P, CO) (3), Me(2)PC(2)H(4)PPh(2) (4), (S,S)-Ph(2)PCHMeCHMePPh(2) (5), SRR' = MeSPh (a), MeS-i-Pr (b), MeSBz (c), i-PrSBz (d), EtSBz (e), MeSCy (f), SC(4)H(8) (g)) were synthesized from the corresponding chloro complexes [Cp(LL')RuCl] and thioethers. 5a crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 11.269(3) Å, b = 15.104(2) Å, c = 23.177(4) Å, and Z = 4. 5b crystallized in the monoclinic system, space group P2(1) (No. 4), with a = 10.539(5) Å, b = 16.216(9) Å, c = 11.011(8) Å, beta = 106.04(2) degrees, and Z = 2. A similar ligand exchange reaction yielded the analogous sulfoxide complexes [Cp(LL')Ru(S(O)RR')]PF(6) (6-10). 10a crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 14.1664(13) Å, b = 15.792(2) Å, c = 17.641(2) Å, and Z = 4. 10b.0.93CH(2)Cl(2) crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 12.069(2) Å, b = 17.379(2) Å, c = 19.760(5) Å, and Z = 4. The thioether complexes can also be directly converted to sulfoxide complexes with the strong oxygen transfer reagent dimethyldioxirane (DMD). No crossover products are formed when mixtures of two thioether complexes (e.g., 1a/2c or 1c/2a) are treated with DMD, demonstrating that no Ru-S bond cleavage is involved. Moderate diastereoselectivities are observed for the oxygen transfer to chiral, racemic thioether complexes 3 (8-28%) and 4 (34-60%). Oxidation of the (S,S)-CHIRAPHOS complexes 5, however, is highly stereoselective (de = 46-98%). Treatment of the sulfoxide complexes 10 with sodium iodide removes the chiral, nonracemic sulfoxides from the metal with retention of the configuration at sulfur.

The Relative Reactivity of Thioethers and Sulfoxides toward Oxygen Transfer Reagents: The Oxidation of Thianthrene 5-Oxide and Related Compounds by MoO5HMPT

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Relative Reactivity of Thioethers and Sulfoxides toward Oxygen Transfer Reagents: The Oxidation of Thianthrene 5-Oxide and Related Compounds by MoO5HMPTMarcella Bonchio, Valeria Conte, Maria Assunta De Conciliis, Fulvio Di Furia, Francesco Paolo Ballistreri, Gaetano Andrea Tomaselli, and Rosa Maria ToscanoCite this: J. Org. Chem. 1995, 60, 14, 4475–4480Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July 1995https://doi.org/10.1021/jo00119a026RIGHTS & PERMISSIONSArticle Views403Altmetric-Citations55LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) Get e-Alerts Get e-Alerts

The relative reactivity of thioethers and sulfoxides toward oxygen transfer reagents: The case of dioxiranes

The relative reactivity of thioethers and sulfoxides toward oxygen transfer reagents: The case of dioxiranes

The relative reactivity of thioethers and sulfoxides toward oxygen transfer reagents: the case of dioxiranes

In the competitive oxidation of thioethers and sulfoxides by electrophilic reagents the reactivity ratio may be small enough to cause the formation of mixtures of products. This has been studied in the reaction of dimethyldioxirane, DMD, and trifluoromethyl-methyldioxirane, TMMD. In particular TMMD oxidizes both thioethers and sulfoxides whereas DMD attacks only thioethers. By applying the logic which has been used to develop mechanistic probes based on such competitive oxidations, the unrealistic conclusion that TMMD is less electrophilic than DMD would be reached. On the contrary we show also by means of Hammett plots on substituted sulfoxides that DMD and TMMD are both electrophilic oxidants toward sulfoxides and that TMMD is less selective than DMD being a stronger oxidant.

Action d'un tétrafluoroborate d'oxaziridinium sur les amines et les imines

The Oxaziridinium salt 1 derived from dihydroisoquinolin is an oxygen transfer reagent to primary amines leading to nitrosoderivatives (if R= Alkyl) or nitro compounds (if R= Aryl), to tertiary amines leading to N-oxides, and to secondary amines and imines leading to the corresponding nitrone.

Kinetics and mechanisms of the redox reactions of the hydroperoxochromium(III) ion

The reactions of the hydroperoxochromium(III) ion, (H[sub 2]O)[sub 5]CrO[sub 2]H[sup 2+] (CrO[sub 2]H[sup 2+]), with Fe[sup 2+], VO[sup 2+], V[sup 2+], Cu[sup +], Ti[sup 3+], Co([14]aneN[sub 4])[sup 2+], Co(Me[sub 6][14]aneN[sub 4])[sup 2+], Co(tim)[sup 2+], and [Ru(NH[sub 3])[sub 6]][sup 2+] have been studied in acidic aqueous solution. The reactions are accompanied by large negative entropies of activation, [minus]110 J mol[sup [minus]1] K[sup [minus]1] for Fe[sup 2+] and [minus]85 J mol[sup [minus]1] K[sup [minus]1] for Ti[sup 3+]. All the reactions studied follow an isokinetic relationship in that [delta]H[sup [double dagger]] is a linear function of [delta]S[sup [double dagger]]. The same is true for the analogous reactions of H[sub 2]O[sub 2]. It is proposed that the reactions of CrO[sub 2]H[sup 2+] take place by an inner-sphere, Fenton-type process yielding pentaaquaoxochromium(IV), (H[sub 2]O)[sub 5]CrO[sup 2+] (CrO[sup 2+]), an an intermediate. The reactivity of CrO[sub 2]H[sup 2+] as an oxygen transfer reagent is about 20 times greater than that of H[sub 2]O[sub 2]. For example, the reactions with (en)[sub 2]CoSCH[sub 2]CH[sub 2]NH[sub 2][sup 2+] to yield (en)[sub 2]CoS(O)CH[sub 2]CH[sub 2]NH[sub 2][sup 2+] have rate constants 20.5 [+-] 0.4 M[sup [minus]1] s[sup [minus]1] (CrO[sub 2]H[sup 2+]) and 1.36 M[sup [minus]1] s[sup [minus]1] (H[sub 2]O[sub 2]), bothmore » in 0.1 M HClO[sub 4] at 25[degrees]C. The chromyl ion, CrO[sup 2+], oxidizes CrO[sub 2]H[sup 2+] to CrO[sub 2][sup 2+] with a rate constant of (1.34 [+-] 0.06) [times] 10[sup 3] M[sup [minus]1] s[sup [minus]1] in 0.10 M HClO[sub 4] in H[sub 2]O and 266 [+-] 10 M[sup [minus]1]s[sup [minus]1] in D[sub 2]O.« less