Electrochemical detection of the oxidation of alcohols byN-hydroxyethylethylenediamminetriacetatoruthenate(IV)

Zhang, Songsheng; Holl, Lori A.; Shepherd, Rex E.

doi:10.1007/bf02910715

Cited by 17 publications

(9 citation statements)

References 34 publications

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“…+1.39 V for the known Ru II/III and Ru III/IV waves of [Ru-(hedta)(H 2 O)] -. 46,49 But as NO replaces H 2 O in the complex, these waves steadily decrease and new waves at E 1/2 values of -0.10 and +0.98 V vs NHE appear as shown by the voltammograms at 40 and 95 s of NO exposure. Data at other times of 10, 20, 65, and 125 s of NO bubbling produce intermediate and final spectra but are not shown for visualization clarity.…”

Section: Resultsmentioning

confidence: 96%

“…Infrared spectra were recorded on a Perkin-Elmer IR32 instrument with an IR/30S peak pick subroutine. Spectra were compared to previously obtained spectra of Na[Ru(hedta)(H2O)]‚4H2O and related complexes in order to assign carboxylate stretches and vibrations attributable to the [Ru II (hedta)(H2O)]chromophore [46][47][48] that are background vibrations to those of coordinated NO + , NO‚, NO2 -, and NO -. Electrochemical measurements were performed using an IBM 225 electrochemical analyzer with the standard three-electrode arrangement.…”

Section: Methodsmentioning

confidence: 99%

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¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

1999

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[Ru(II)(hedta)L](n)()(-) complexes (hedta(3)(-) = N-(hydroxyethyl)ethylenediaminetriacetate; L = NO(+), n = 0; L = NO, n = 1; L = NO(-), n = 2) have been prepared by the displacement of H(2)O/D(2)O via NO(g) or NO(2)(-). This is the first reported entire set of NO(+), NO, and NO(-) as ligands for the same metal center in a constant oxidation state and with a constant ligand environment (here Ru(II) and the amino carboxylate hedta(3)(-)). From the NO stretching frequencies of isolated salts, the net influence of back-donation by Ru(II) and its sigma-withdrawal was observed to be that the bond order for the NO(+) complex is virtually the same (ca. 2.46) as that for the NO complex (ca. 2.48). The back-donation to NO(-) is also small, as is that to NO, but orbital mixing of NO(-) and Ru(II) is sufficiently important to induce a singlet NO(-) complex. Values for the nu(NO) in cm(-)(1) for the (14)N- and (15)N-labeled complexes, respectively, are as follows: NO(+), 1846, 1827; NO, 1858, 1842; NO(-), 1383, 1370. Combined results of (15)N, (13)C, and (1)H NMR spectra of the complexes in D(2)O show that [Ru(II)(hedta)((15)NO(+))] is a single cis-equatorial isomer with its (15)NO(+) resonance at 249.6 ppm vs [(15)N]formamide. The two-electron-reduced [Ru(II)(hedta)((15)NO(-))](2)(-) complex exists as trans- and cis-equatorial isomers having (15)NO(-) resonances at 609.4 and 607.4 ppm. The (15)N resonances appear at 260.0 ppm for the (15)NO(+) ligand and at 348.8 ppm for the bound (15)NO(2)(-) ligand in the [Ru(II)(hedta)((15)NO(2)(-))((15)NO(+))(D(2)O)] complex. Differential pulse voltammetric waves for the [Ru(II)(hedta)L](n)()(-) series occur at -0.37 V for the Ru(II)(NO(-))/Ru(II)(NO) couple, at -0.10 V for the Ru(II)(NO)/Ru(II)(NO(+)) couple, and at +0.98 V for the Ru(II)(NO(+))/Ru(III)(NO(+)) couple. The coordinated nitrosyl ion/nitro equilibrium (L')Ru(II)(NO(+)) + 2OH(-) right harpoon over left harpoon (L')Ru(II)(NO(2)(-)) + H(2)O (K(NO)()2()-) was observed for L' = hedta(3)(-), as for previous examples with L' = violurate, polypyridyl ligands, and (CN(-))(5) and (NH(3))(5) ligand sets. K(NO)()2()- = 1.44 x 10(13) for L' = hedta(3)(-). log(K(NO)()2()-) is linearly related through the ion-pairing equilibrium constant expression to -z(1)z(2), the charge product of the reacting ions (here the (L')Ru(NO(+)) complex and OH(-)) from -4 through +3, excluding the (NH(3))(m)() ammine series with m = 4 and 5. The opposite behavior of the ammines is attributed to strong solvent H-bonding that changes for reactant and product in the nitrosyl/nitro equilibrium. The pK(a) of coordinated nitrous acid in [Ru(II)(hedta)(HONO)](-) is calculated to be -0.80, a 3.85 log unit enhancement over free HONO due to the Ru(II) charge. An MO explanation is presented to interrelate the {Fe(III)-(NO(-) triplet)} complexes, the {Ru(II)-(NO(-) singlet)} type observed for [Ru(II)(hedta)((15)NO(-))](2)(-), and the NO(+) complexes of other strong-field metals. When both d(z)()()2 and d(x)()()2(-)(y)()()2 metal orbitals reside below the NO pi pair, the...

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Section: Resultsmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

1999

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“…During the last decade the catalytic activity of Ru III (pac) (pac = polyaminocarboxylate) complexes towards hydrocarbon oxidation using various precursor oxidants has been well documented in the literature. [3][4][5][6] (pac)Ru V =O species have been proposed as catalytic active intermediates in oxygen transfer processes. The (pac)Ru V =O intermediates (pac = edta and pdta) have been isolated and characterized by elemental analysis, UV-Vis, IR, EPR, electrochemical and magnetic susceptibility studies.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of the reaction of [Ru^III(edta)(H₂O)]⁻with HOBr to form an intermediate Ru^VO complex in aqueous solution

2006

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The interaction of [Ru(III)(edta)(H(2)O)](-) (1) (edta = ethylenediaminetetraacetate) with the oxygen transfer agent HOBr, was studied kinetically as a function of [HOBr] and temperature (5-35 degrees C) at a fixed pH of 6.2. Spectroscopic evidence is reported for the formation of a high valent intermediate (edta)Ru(V)=O complex. Water soluble 2,2'-azobis(3-ethylbenzithiazoline-6-sulfonate) (ABTS) was employed as a trap for this intermediate in order to gain further mechanistic information. Reactions were carried out under pseudo-first conditions for [ABTS] >> [HOBr] >> [1], and were monitored as a function of time for the formation of the one-electron oxidation product ABTS(*+). The reported kinetic data are interpreted in terms of a suggested reaction mechanism and discussed in reference to data reported before.

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“…Spectra were obtained on 300 MHz Bruker and 500 MHz Bruker n.m.r. spectrometers (1)(2)(3). Assignments of 1Hn.m.r.…”

Section: Introductionmentioning

confidence: 99%

Five coordination modes of 4-aminopyrimidine with N-hydroxy-ethylethylenediaminetriacetatoruthenate(II)

Shepherd

Zhang

1994

Transition Met Chem

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The complex [Run(hedta)(4NHzpym)] -, hedta 3-= N-hydroxyethylethylenediaminetriacetate, 4NH2pym = 4-aminopyrimidine, exists at pH 7 as five different coordination isomers, which are most readily distinguished by their electrochemical waves in comparison with the 2-aminopyridine (2NH2py) complex. The 2NH2py complex exhibits N(1) (pyridine bound), exo-NH2 (amine bound) and N(1), NH2-chelated species. The 4NH2pym complex forms N(1), exo-amine and N(3), NHz-chelated isomers analogues to the 2NH2py species, but also engages in t? 2 (olefin bound) coordination of the dearomatized 4NH2pym ring in C(5)-C(6), and another r/2 type of complex involving electron density between N(l) and N(3) of the ring (tl 3 form). N(1), 1/2 and q3 isomers have also been detected for unsubstituted pyrimidine (pym), 4-methylprilnidine (4CH 3pym) and 2-aminopyrimidine (2NH 2pym). Electrochemical waves (V versus NHE) for the five isomers are assigned as follows: (Ru l~/m) exo-NH 2 (0.06 V), N(1) (0.29 V), y/2 (0.49 V); (Ru m'/w) r/3 (0.76 V); N(3), NH2-chelated (1.09 V).

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Electrochemical detection of the oxidation of alcohols byN-hydroxyethylethylenediamminetriacetatoruthenate(IV)

Cited by 17 publications

References 34 publications

¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

Kinetics and mechanism of the reaction of [Ru^III(edta)(H₂O)]⁻with HOBr to form an intermediate Ru^VO complex in aqueous solution

Five coordination modes of 4-aminopyrimidine with N-hydroxy-ethylethylenediaminetriacetatoruthenate(II)

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Electrochemical detection of the oxidation of alcohols byN-hydroxyethylethylenediamminetriacetatoruthenate(IV)

Cited by 17 publications

References 34 publications

15N NMR and Electrochemical Studies of [RuII(hedta)]- Complexes of NO, NO+, NO2-, and NO-

15N NMR and Electrochemical Studies of [RuII(hedta)]- Complexes of NO, NO+, NO2-, and NO-

Kinetics and mechanism of the reaction of [RuIII(edta)(H2O)]−with HOBr to form an intermediate RuVO complex in aqueous solution

Five coordination modes of 4-aminopyrimidine with N-hydroxy-ethylethylenediaminetriacetatoruthenate(II)

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Product

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¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

¹⁵N NMR and Electrochemical Studies of [Ru^II(hedta)]^- Complexes of NO, NO⁺, NO₂^-, and NO^-

Kinetics and mechanism of the reaction of [Ru^III(edta)(H₂O)]⁻with HOBr to form an intermediate Ru^VO complex in aqueous solution