The dinuclear palladium(II) complex of pyridine-2-thiol. Synthesis, structure, and electrochemistry

Umakoshi, Keisuke; Ichimura, Akio; Kinoshita, Isamu; Ooi, Shun’ichiro

doi:10.1021/ic00345a019

Cited by 113 publications

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“…(1)-(3) should be replaced by a two-electron process where both palladium ions are oxidized at the same potential. The response for Pd 2 L 2 plus Cl − solutions parallels that described by Umakoshi et al [20] and Bond et al [25] for dinuclear palladium(II) complexes with different pyridin derivatives, consisting of a two-electron oxidation with incorporation of two chloride ions. This can tentatively be represented as: For Pd 2 L 2 , the peak potential of A 1 remains essentially independent on the square wave frequency, f, as expected for a reversible oxidation process minimally affected by post-electron transfer reactions [34,37].…”

Section: Solution Phase Electrochemistrysupporting

confidence: 83%

“…This reaction probably consists of a ligand re-organization, so that the voltammetric response can be formally described in terms of a square-scheme involving two successive reversible one-electron transfer steps. The overall electrochemical process involves the oxidation of Pd II Pd II L 2 dimer species to Pd II Pd III L 2 and Pd III Pd III L 2 ones, successively, a scheme common with other dinuclear palladium complexes [18,20]. The overall reaction can be represented as:…”

Section: Solution Phase Electrochemistrymentioning

confidence: 99%

“…This variation suggests that the electron transfer process is preceded by a complexation with chloride ions. Following the procedure described by Umakoshi et al [20], the peak potential value of A 3 remained essentially constant for Cl − /Pd 2 L 2 molar ratios larger than ca. 2.0, suggesting that a Pd 2 L 2 Cl 2 adduct is electrochemically generated.…”

Section: Solution Phase Electrochemistrymentioning

confidence: 99%

“…This is the case of some dinuclear palladium(II) complexes containing two bridging ligands and two cyclometalated units with the ligand having a chelating coordination mode [15]. The availability of high oxidation states of palladium and the possibility of modulating the reactivity of the complexes via synergic interaction between the metal centres can be considered as relevant factors with regard to the use of such compounds in catalysis [16], so that different dinuclear palladium compounds with bridging ligands have been synthesized [17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…Since the electrocatlytic process may involve coordination of glutamic acid (strictly, glutamate ion) with the Pd 2 L 2 complex coupled with oxidation/reduction cycles, the electrochemical response of Pd 2 L 2 in CH 2 Cl 2 solution and in solid state in the presence of chloride and acetate ions has also been studied. These preliminary studies are motivated by the recognized dependence of the catalytic ability of dinuclear palladium complexes on the extent of the possible synergic interaction between metal atoms [16][17][18][19][20][21][22][23][24][25], and the ability of exogen ligands such as chloride or carboxylate for modulating such interaction [18,20,25]. Interestingly, oxidation potentials and electrochemical reversibility are significantly influenced by the ligand nature, as can be seen on comparing reported electrochemical data for palladium dinuclear complexes with pyridines [20,25] and those with carboxylates [28].…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Doménech

Koshevoy

Penno

et al. 2008

Electrochimica Acta

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Section: Solution Phase Electrochemistrysupporting

confidence: 83%

Section: Solution Phase Electrochemistrymentioning

confidence: 99%

Section: Solution Phase Electrochemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Doménech

Koshevoy

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et al. 2008

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Pyridin‐2‐thiolatokomplexe von V^II, V^III und V^IV mit ungewöhnlichen Strukturmerkmalen

et al. 1992

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Unser anhaltendes Interesse fur die Vanadium-Schwefel-Chemie resultiert unter anderem aus der Relevanz dieses Gebietes fur die industrielle Erdolraffnation. Bestimmte Rohole enthalten grol3e Mengen an Vanadyl(V0 2+)-Verunreinigungen"], die sich bezuglich der Liganden unterteilen lassen, und zwar in Vanadylpetroporphyrine, die gut untersucht und charakterisiert wurdenL2], und Vanadylnichtporphyrine, deren Liganden vermutlich S-, N-und/oder O-Donoratome enthaltenl3I. In Gegenwart dieser Vanadylverunreinigungen werden aus schwefelreichen Verbindungen unter den reduzierenden und hydrierenden Bedingungen Vanadiumsulfide, vor allem V,S, und V,S,, gebildetI41. Diese Sulfide wirken sich nachteilig auf die Aktivitat und die Lebensdauer des bei der Roholveredlung eingesetzten heterogenen Katalysators (2.B. Mo/Co/S auf Aluminiumoxid) aus. Um die fortschreitende Reduktion, Sulfidierung und Aggregation von V 0 2 +-Verunreinigungen im Rohol nachzubilden, haben wir verschiedene ein-bis vierkernige Vanadium-Schwefel-Verbindungen mit mehreren Thiolatoliganden und mit Oxidationsstufen von III bis v untersuchtL5 -"1. In letzter Zeit haben wir rnit dem Liganden Pyridin-2-thiol (pytH) gearbeitet, da er in Roholen haufig vorkommende funktionelle Gruppen enthllt (S als Thiolatfunktion und N in Arenen) und auI3erdem gegenuber iibergangsmetallen sowohl als Chelatals auch als Briickenligand fungieren kann ["]. Wir berichten hier uber die Synthese von V"-, V"' -und V'"-Komplexen mit pyt--Liganden und ungewohnlichen Strukturmerkmalen und beschreiben eines der sehr seltenen Beispiele von Thiolatovanadium(i1)-Komplexen.Werden zwei Aquivalente Na(pyt) zu einer Losung von [VOCl,(thf),] in THF gegeben, so entsteht der Vanadium(1v)-Komplex l[13'. Die Struktur von 1 (Abb. zeigt eine ungewohnliche verbriickende Anordnung von zwei ,u2-r11 : $-pyt --Liganden, wobei das N6-Atom des Pyridinrings zur Grundflache einer quadratisch pyramidalen Anordnung (N 6, N 5, S 2, S 3', 0 4) an V1 zahlt, wahrend das an diesen Pyridinring gebundene Schwefelatom S 3 zur entsprechenden quadratischen Grundflache an V 1' gehort [V 1'-S 3 = 2.457(4) A]. Als sechstes koordinierendes Atom ist S 3 trans zum Oxoliganden an V 1 gebunden [V 1-S3 = 2.798(3) A]. Komplex 1 ist ein sehr seltenes Beispiel fur eine Verbindung rnit unsymmetrischer pyt--Brucke" '1. An beiden Metallen wird die Koordinationssphare durch zwei chelatbildende pyt --Liganden vervollstandigt. Der V-O-Abstand ist mit 1.583(6) 8, normal fur eine dreifach gebundeneVanadyleinheit, und das ganze Molekul hat kristallographisch bedingte C,-Symmetrie. Bei Raumternperatur in CH,C12 oder THF aufgenommeiie X-Band-ESR-Spektren 1 zeigen nur die typischen isotropen 8-Linien-Signale, die fur einkernige VOz +-Verbindungen charakteristisch sind; dies deutet darauf hin, daD entweder die zweikernige Komplexanordnung in Losung nicht erhalten bleibt oder zwischen den Metallzentren keinerlei Wechselwirkung besteht. Abb. 1. ORTEP-Darstellung von Komplex 1 (Ellipsoide mit 50% Wdhrscheinlichkeit). Die Atome mit und ohne Strichindex si...

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Pyridine‐2‐thiolato Complexes of V^II, V^III, and V^IV with Unusual Structural Features

Reynolds

Sendlinger

Murray

et al. 1992

Angew. Chem. Int. Ed. Engl.

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Se-CI bonds and the Se-Cl bridging bond. Figure4 (left) shows the Laplacian distribution of the electron density of 1. Whereas the electron density distribution of the bridging C1 atom is spherically symmetrical, the terminal Cl atoms show a significant distortion of the electron density distribution and an overlap with the electron density of the Se atoms. This indicates a covalent character for the terminal Se-Cl bonds, whereas the bridging C1 atom is rather ionically bound. The calculation of the charge distribution according to M~l l i k e n~"~ supports this interpretation ( Table 1). The bridging C1 atom with a partial charge of -0.61 is clearly more negatively charged than the terminal C1 atoms (-0.21). The Se atoms in 1 have a positive partial charge (+ 0.69), which in the cation of 2 is almost identical (+ 0.70). The Laplacian distribution of the U-shaped cation (Fig. 4 right) shows that the only significant difference to the corresponding structural unit in 1 is the orientation of the Se-N-Se unit. Obviously the repulsion between the in-plane orbitals of the lone pairs at C1 and at N in the W-shaped structure of the cation of 2 is greater than that between Se and N in the U-shaped structure. Fig, 4. Laplacian distribution of the electron density in 1 (left) and in the cation of 2 (right).The calculated frequency spectra for 1 and for the cation of 2 show that the optimized structures are minima on the potential energy hypersurface (no negative eigenvalues of the Hessian matrix). In agreement with the experiment a frequency shift to higher wavenumbers is calculated for the highest positioned band (v,,(Se-N-Se), b2) from 862 cm-' (1) to 909 cm-(cation of 2) during the formation of 2 from 1. Experimental Procedure1: A solution of tris(trimethylsily1)amine (2.2 g, 9.4 mmol) in CH,CI, (20 mL) was added dropwise to a suspension of SeCI, (4.1 g, 18.7 mmol) in CH,CI, (30 mL) and stirred. This was refluxed for 12 h, filtered to remove small amounts of unreacted SeCI,, and after concentration to 10 mL cooled to 5 "C. The red crystals were separated by filtration, washed with a little cold CH,CI,, and dried in vacuum (yield 1.5 g, 57 %, based on SeCI,, m.p. 69°C). The chlorine formed by this reaction reacted with a part of the tris(trimethysilyl)amine. An improvement in the yield strived for by the addition of larger quantities of amine is not advisable since explosive by-products are formed.

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The dinuclear palladium(II) complex of pyridine-2-thiol. Synthesis, structure, and electrochemistry

Cited by 113 publications

References 0 publications

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Pyridin‐2‐thiolatokomplexe von V^II, V^III und V^IV mit ungewöhnlichen Strukturmerkmalen

Pyridine‐2‐thiolato Complexes of V^II, V^III, and V^IV with Unusual Structural Features

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The dinuclear palladium(II) complex of pyridine-2-thiol. Synthesis, structure, and electrochemistry

Cited by 113 publications

References 0 publications

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Electrochemical chiral recognition by microparticle coatings of Pd complexes with bridging cyclometalated phosphines

Pyridin‐2‐thiolatokomplexe von VII, VIII und VIV mit ungewöhnlichen Strukturmerkmalen

Pyridine‐2‐thiolato Complexes of VII, VIII, and VIV with Unusual Structural Features

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Pyridin‐2‐thiolatokomplexe von V^II, V^III und V^IV mit ungewöhnlichen Strukturmerkmalen

Pyridine‐2‐thiolato Complexes of V^II, V^III, and V^IV with Unusual Structural Features