Electron transfer properties of rhodium(I) oxalate complexes

Anderson, James E.; Murphy, Catherine P.; Real, J.; Balué, J.; Bayón, J. Carles

doi:10.1016/s0020-1693(00)85136-1

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…Almost the same voltammograms were obtained for compounds (2) and (3), which contain the same binuclear anion [Mo 2 O 6 (C 2 O 4 ) 2 ] 4− core. An irreversible oxidative signal at +0.46 V vs Fc + /Fc can be observed, which is tentatively attributed to the oxidation of the oxalate ligands on the basis of previous studies of metal oxalate complexes [42] or oxalate ions alone [43]. Two mono-electronic reduction signals can also be seen at −1.95 and −2.21 V vs Fc + /Fc (−1.51 and −1.77 V respectively vs SCE) which probably correspond to the sequential reduction processes of the Mo VI ions (Mo VI -Mo VI → Mo V -Mo VI and Mo V -Mo VI → Mo V -Mo V ).…”

Section: Redox Propertiessupporting

confidence: 60%

One pot-synthesis of the fourth category of dinuclear molybdenum(VI) oxalate series: Structure and study of thermal and redox properties

Sarr

Mbaye

Diop

et al. 2019

Inorganica Chimica Acta

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Three new dinuclear molybdenum(VI) oxalate (Pr 2 NH 2) 4 •[M�0 6 (¼0 4 hl (1), (�r 2 NH;J 4 •[M�0 6 (¼0 4 h] (2) and (HDabco) 4 [Mo 2 0 6 (C 2 0 4 hJ-2H 2 0 (3) compounds, have been prepared by one pot-synthesis at room temperature and characterized by single crystal X-ray diffraction and vibrational spectroscopies. F.ach compound contains the binuclear [Mo 2 0 6 (¼0 4 h] 4-anion where each molybdenum is in an octahedral Mo0 6 environment. ln compound (3), the interconnection between [M0206(C204)2J 4-anions, [HDabco] + cations and water molecules (H20) leads to an infinite inorganic-organic chain structure. Similarly, in compounds (1) and (2) the interactions between [Mo206(C2Ü 4hJ4-anions and respectively [Pr 2NH2l + and [ i Pr�2l + cations leads to an infinite inorganic-organic chain structure. A remarkable difference between the compounds is that in compounds (1) and (2) interactions between the chains involve only Van der Waals forces giving rise to layer-like structures, which also interact between them only by Van der Waals forces, whereas in compound (3) the chains interact also through hydrogen bonds giving a 30 supramolecular structure. The thermal properties of the compounds were investigated through thermogravimetric and differential thermal analyzes. The differences in the thermal decomposition of the compounds in the solid state are discussed in relation with their crystal structure. Cyclic voltammetry shows that the [Mo 2 0 6 (¼0 4 h] 4-anion can be reduced in both aprotic solvent and water.

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Section: Redox Propertiessupporting

confidence: 60%

One pot-synthesis of the fourth category of dinuclear molybdenum(VI) oxalate series: Structure and study of thermal and redox properties

Sarr

Mbaye

Diop

et al. 2019

Inorganica Chimica Acta

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“…A twoelectron process to generate a rhodium(III) centre was also found for the CV of [Rh(oxalate)(cod)] -. 18 That the overall oxidation process involved a flow of three electrons was confirmed by bulk electrolysis. Fig.…”

Section: Resultsmentioning

confidence: 94%

Relationship between electrochemical potentials and substitution reaction rates of ferrocene-containing β-diketonato rhodium(i) complexes; Cytotoxicity of [Rh(FcCOCHCOPh)(cod)]

Conradie

Swarts

2011

Dalton Trans.

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A series of ferrocene-containing rhodium complexes of the type [Rh(FcCOCHCOR)(cod)] (cod = 1,5-cyclooctadiene) with R = CF(3), 1, (E(pa)(Rh) = 269; E(o)'(Fc) = 329 mV vs. Fc/Fc(+)), CCl(3), 2, (E(pa) = 256; E(o)' = 312 mV), CH(3), 3, (E(pa) = 177; E(o)' = 232 mV), Ph = C(6)H(5), 4, (E(pa) = 184; E(o)' = 237 mV), and Fc = ferrocenyl = (C(5)H(5))Fe(C(5)H(4)), 5, (E(pa) = 135; E(o)'(Fc1) = 203; E(o)'(Fc2) = 312 mV), have been studied electrochemically in CH(3)CN. Results indicated that the rhodium(I) centre is irreversibly oxidised to Rh(III) in a two-electron transfer process before the ferrocenyl fragment is reversibly oxidized in a one-electron transfer process. The peak anodic (oxidation) potential, E(pa), (in V vs. Fc/Fc(+)) of the rhodium core in 1-5 relates to k(2), the second-order rate constant for the substitution of (FcCOCHCOR)(-) with 1,10-phenanthroline in [Rh(FcCOCHCOR)(cod)] to form [Rh(phen)(cod)](+) in methanol at 25 °C with the equation lnk(2) = 39.5 E(pa)(Rh) - 3.69, while the formal oxidation potential of the ferrocenyl groups in 1-5 relates to k(2) by lnk(2) = 40.8 E(o)'(Fc)-6.34. Complex 4 (IC(50) = 28.2 μmol dm(-3)) was twice as cytotoxic as the free FcCOCH(2)COPh ligand having IC(50) = 54.2 μmol dm(-3), but approximately one order of magnitude less toxic to human HeLa neoplastic cells than cisplatin (IC(50) = 2.3 μmol dm(-3)).

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“…This mechanism occurs without discernible intermediates such as free radicals. 20 Thus, for reduction mechanism studies, it is required to clarify whether the reaction occurs through 1e-and/or 2e reductions. As aforementioned, no light is required for QH 2 to reduce the aquatic mercuric ion to Hg 0 , but it remains uncertain if the mechanism is intramolecular 2e transfer as it is for the environmentally relevant Hg 2+ + SO 3 2− reaction occurring in the dark.…”

Section: ■ Introductionmentioning

confidence: 99%

“…For second- and third-row transition metal ions that are relatively stable when complexed in low-oxidation states that differ by two units (e.g., Re I/III , Rh I/III , Ir I/III , Pd 0/II , Pt 0/II ), photochemical metal-oxalate reductive elimination via ligand fragmentation has been documented. , Thus, 2e-LMCT occurs here photoinduced as part of a concerted series of electron rearrangements (heterolytic breaking of σ-bonds in the complex), resulting in the oxalate ligand being eliminated as two molecules of CO 2 and the oxidation number of the metal ion decreasing by two units. This mechanism occurs without discernible intermediates such as free radicals . Thus, for reduction mechanism studies, it is required to clarify whether the reaction occurs through 1e- and/or 2e reductions.…”

Section: Introductionmentioning

confidence: 99%

Chemistry and Isotope Fractionation of Divalent Mercury during Aqueous Reduction Mediated by Selected Oxygenated Organic Ligands

Zhao

Meng

Sun

et al. 2021

Environ. Sci. Technol.

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We have investigated the chemistry and Hg isotope fractionation during the aqueous reduction of Hg II by oxalic acid, pquinone, quinol, and anthraquinone-2,6-disulfonate (AQDS), a derivate of anthraquinone (AQ) that is found in secondary organic aerosols (SOA) and building blocks of natural organic matter (NOM). Each reaction was examined for the effects of light, pH, and dissolved O 2 . Using an excess of ligand, UVB photolysis of Hg II was seen to follow pseudo-first-order kinetics, with the highest rate of ∼10 −3 s −1 observed for AQDS and oxalic acid. Mass-dependent fractionation (MDF) occurs by the normal kinetic isotope effect (KIE). Only the oxalate ion, rather than oxalic acid, is photoreactive when present in HgC 2 O 4 , which decomposes via two separate pathways distinguishable by isotope anomalies. Upon UVB photolysis, only the reduction mediated by AQDS results in a large odd number mass-independent fractionation (odd-MIF) signified by enrichment of odd isotopes in the reactant. Consistent with the rate, MDF, and odd-MIF reported for fulvic acid, our AQDS result confirms previous assumptions that quinones control Hg II reduction in NOM-rich waters. Given the magnitude of odd-MIF triggered via a radical pair mechanism and the significant rate in the presence of air, reduction of Hg II by photoproducts of AQDS may help explain the positive odd-MIF observed in ambient aerosols depleted of Hg II .

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Electron transfer properties of rhodium(I) oxalate complexes

Cited by 5 publications

References 28 publications

One pot-synthesis of the fourth category of dinuclear molybdenum(VI) oxalate series: Structure and study of thermal and redox properties

One pot-synthesis of the fourth category of dinuclear molybdenum(VI) oxalate series: Structure and study of thermal and redox properties

Relationship between electrochemical potentials and substitution reaction rates of ferrocene-containing β-diketonato rhodium(i) complexes; Cytotoxicity of [Rh(FcCOCHCOPh)(cod)]

Chemistry and Isotope Fractionation of Divalent Mercury during Aqueous Reduction Mediated by Selected Oxygenated Organic Ligands

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