Electrochemistry of molybdenum(VI,V)-8-quinolinol complexes in dimethyl sulfoxide

Isbell, A. F.; Sawyer, Donald T.

doi:10.1021/ic50105a018

Cited by 41 publications

(9 citation statements)

References 4 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(The model compounds used for this comparison are di-^-sulfido Mo(V) complexes with dialkyldithiocarbamate and chronopotentiometric measurements in dimethyl sulfoxide. 41 The chronoamperometric results confirm the assignment of successive one-electron transfers (eq 4 and 5) to the reduction of the Mo202X2(Etcys)2 complexes. In addition to a reversible first electron transfer, the second electron transfer of Mo202S2(Etcys)2 also becomes reversible at v > 4 V s~'.…”

Section: Resultssupporting

confidence: 65%

Di-.mu.-oxo, .mu.-oxo-.mu.-sulfido, and di-.mu.-sulfido complexes of molybdenum(V) with EDTA, cysteine, and cysteine ester ligands. Preparation and electrochemical and spectral properties

Ott¹,

Swieter²,

Schultz³

1977

Inorg. Chem.

View full text Add to dashboard Cite

Preparative methods and electrochemical and spectral properties are reported for binuclear Mo(V) complexes containing di-µ-(Mo2042+), µ--µ-sulfido (Mo203S2+), and di^-sulfido (Mo202S22+) centers coordinated to EDTA, cysteine, and ethyl cysteinate ligands. The µ--µ-sulfido complexes are prepared here for the first time, and improved synthetic procedures are reported for the di^-sulfido complexes. Infrared and electronic absorption spectra of these compounds are sensitive to substitution of sulfur atoms into the bridge system. The systematic changes upon bridge modification are useful in characterizing the compounds and in clarifying assignments of Mo-O and Mo-S bridge stretching frequencies.The EDTA and cysteine complexes undergo electrochemical reduction in a single four-electron step to Mo(III) dimers in aqueous buffers. Although the ease of reduction and electrochemical reversibility of the Mov2/Mom2 couple increase with insertion of S into the bridge system, the Mo(III) dimers become increasingly unstable upon bridge sulfur substitution.The corresponding ethyl cysteinate complexes are reduced by successive one-electron transfers in dimethyl sulfoxide to Mov-Molv and Mo,v2 species. The chemical stability of these reduced products increases in the sequence Mo204 < Mo203S < Mo202S2. The different behavior of sulfido bridging is attributed to greater lability of Mom-S bonds in the former case and to greater electron delocalization by sulfur atoms over the binuclear framework in the latter.

show abstract

Section: Resultssupporting

confidence: 65%

Di-.mu.-oxo, .mu.-oxo-.mu.-sulfido, and di-.mu.-sulfido complexes of molybdenum(V) with EDTA, cysteine, and cysteine ester ligands. Preparation and electrochemical and spectral properties

Ott¹,

Swieter²,

Schultz³

1977

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…A similar value of D = 2.2 X 10"ĉ m2 s"1 has been obtained for the µ--bridged 8-quinolinol complex, Mo203Q4, from chronopotentiometric measurements in Me2S0. 26 Selection of other values of n yields diffusion coefficients which are unreasonable for molecules of this size in dimethyl sulfoxide. Under conditions where forward and reverse peaks are observed for the dtc complexes, values of the peak width (£p -E^2) and peak separation ( £ ) are ~70 and 70-80 mV, respectively.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and electrochemistry of oxo- and sulfido-bridged molybdenum(V) complexes with 1,1-dithiolate ligands

Schultz¹,

Ott²,

ROLISON³

et al. 1978

Inorg. Chem.

View full text Add to dashboard Cite

“…Similar results have been reported by others. 8 The Mo(IV) complexes produced in the controlled-potential reductions are probably pentacoordinate oxo complexes,2 although this is not certain. The only Mo(IV) complex with any of these ligands reported in the literature is MoO(ox)2;…”

Section: Resultsmentioning

confidence: 99%

Electrochemistry of monomeric molybdenum(V)-oxo complexes in dimethylformamide

Taylor¹,

Street²,

Minelli³

et al. 1978

Inorg. Chem.

View full text Add to dashboard Cite

The electrochemistry of nine monomeric molybdenum(V)-oxo complexes in dimethylformamide has been investigated by cyclic voltammetry and controlled-potential coulometry at a platinum electrode. MoOC13L (L = o-phenanthroline, ol,a'-bipyridyl), MoOClL2 (L = 8-hydroxyquinoline, 8-mercaptoquinoline), and MoOClL (L = disalicylaldehyde ophenylenediimine, N,N'-dimethyl-N,N'-bis(2-mercaptoethyl)ethylenediamine, N,N'-bis(2-mercapto-2-methylpropyl)-ethylenediamine) are facilely reduced by one-electron reductions to Mo(1V) species. (C2H5)4NMoOC12(salicylaldehyde o-hydroxyanil) is reduced in a two-electron step to an Mo(1II) species. None of the complexes are oxidizable in the voltage range used (+OS0 to -2.50 V vs. SCE) to Mo(V1) complexes. Comparison with reduction peaks for molybdenum(V1)-dioxo complexes indicates the Mo(V) monomers are not obtainable by electrochemical reduction of the Mo(V1) complexes, and are, in some cases, thermodynamically unstable to disproportionation into Mo(1V) and Mo(V1). Implications for redox states in molybdenum enzymes are discussed. IntroductionMolybdenum is now well established as a necessary cofactor for a number of redox and there is considerable current interest in the properties and reactions of its complexes as possible models for these During catalysis, Mo(V) has been identified by electron spin resonance (ESR) spectrometry for the molybdenum enzymes xanthine oxidase, aldehyde oxidase, sulfite oxidase, and nitrate redu~tase.',~*~ The ESR signal appears to arise from a monomeric Mo(V) center as a result of electron transfer to or from the ~u b s t r a t e . '~~~~ Clearly, a knowledge of the structures, properties, and reactions of monomeric Mo(V) complexes is of importance for an understanding of these enzymes.The aqueous chemistry of Mo(V) is dominated by ESR

show abstract

Electrochemistry of molybdenum(VI,V)-8-quinolinol complexes in dimethyl sulfoxide

Cited by 41 publications

References 4 publications

Di-.mu.-oxo, .mu.-oxo-.mu.-sulfido, and di-.mu.-sulfido complexes of molybdenum(V) with EDTA, cysteine, and cysteine ester ligands. Preparation and electrochemical and spectral properties

Di-.mu.-oxo, .mu.-oxo-.mu.-sulfido, and di-.mu.-sulfido complexes of molybdenum(V) with EDTA, cysteine, and cysteine ester ligands. Preparation and electrochemical and spectral properties

Synthesis and electrochemistry of oxo- and sulfido-bridged molybdenum(V) complexes with 1,1-dithiolate ligands

Electrochemistry of monomeric molybdenum(V)-oxo complexes in dimethylformamide

Contact Info

Product

Resources

About