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1

Kompleksy platyny typu Markó zawierające n-heterocykliczne ligandy karbenowe o właściwościach supersterycznych

Bolt Małgorzata, Żak Patrycja

Wiadomości Chemiczne

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2021

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[Z] 75, 1-2

31--53

EN

Progress in technology implying increasing demand for advanced materials dedicated for specific application has become a driving force stimulating research in different branches of science. It has been estimated that over 90% highly processed compounds have been obtained by the methods whose pivotal processes take place in the presence of catalysts based on transition metal complexes. Although these processes permit obtaining desired products, they are often charged with numerous drawbacks that prevent their implementation in industry. That is why the search for new catalytic systems ensuring high efficiency of final products and a possibility of reaction control is still an important direction of studies. Markó complexes are a group of platinum(0) coordination compounds of type [(NHC)Pt(dvtms)]. Although much attention has been recently attracted to these class of compounds, their number reported in hitherto literature is still limited. Owing to the possibility of wide modification of NHC carbene ligand attached to metal, the structures, and thus also properties, of the final complexes can be relatively easily matched to the requirements of individual catalytic reactions. It is particularly interesting in view of permanent development of new technologies and still increasing demand for new synthetic methods of more sophisticated materials dedicated to specific applications. In this paper, the synthesis and characterization of Markó type platinum(0) complexes containing bulky N-heterocyclic carbene ligands is described and their applications in the synthesis of new and unknown organic and organosilicon compounds are discussed. The main advantages of these complexes are highlighted providing an overview of this fascinating area of research.

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Kinetics and Mechanism of the Redox Reaction Between Pt(IV) Complex Ions and Sodium Thiosulfate in Aqueous Solution. Part II: Neutral and Alkaline Solution

Pacławski K., Piwowońska J.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1421--1426

EN

In this work, spectrophotometric studies on the kinetics and mechanism of the reaction between [PtCl6]2- complex ions and sodium thiosulfate, in neutral (pH = 7) and alkaline (p = 12) solution, were carried out. Applying different conditions, the influence of initial concentrations of reductant and platinum(IV) complex ions as well as the influence of temperature and ionic strength on the rate constant, was experimentally determined. From the obtained results, the molecularity, the order and the value of enthalpy and entropy of activation of the reaction, were experimentally determined. It was found that in both cases the reduction reaction is relatively slow and in the studied conditions the second-order rate constant changes from 2.92 : 10-2 to 0.40 M-1:s-1 at pH = 7, and from 3.84 : 10-2 to 1.55 M-1s-1 at pH = 12. Additionally, depending on the pH, different mechanism of the reaction is present. However, regardless on the studied system the only platinum(II) chloride complex ions are the final product of the redox reaction.

PL

W pracy, przedstawiono wyniki badań spektrofotometrycznych nad kinetyką i mechanizmem reakcji pomiędzy jonami kompleksowymi [PtCl6]2- i tiosiarczanem sodu, w roztworze obojętnym (pH = 7) i zasadowym (pH = 12). Stosując różne warunki doświadczalne, wyznaczono wpływ stężenia początkowego reduktora oraz stężenia jonów kompleksowych platyny(IV), jak również wpływ temperatury oraz siły jonowej na wartość stałej szybkości reakcji. Na podstawie otrzymanych danych, wyznaczono cząsteczkowość, rząd oraz entalpie i entropie reakcji. Wykazano, że w obydwu przypadkach reakcja redukcji jest stosunkowo wolna. W badanych warunkach wartość drugorzędowej stałej szybkości reakcji ulega zmianie od 2.92· 10-2 do 0.40 M-1:s-1 w roztworze o pH = 7, oraz z 3.84 · 10-2 do 1.55 M-1s-1w roztworze o pH = 12. Dodatkowo, w zależności od pH roztworu, ulega zmianie mechanizm badanej reakcji. Jednakże, bez względu na zastosowane warunki pH, produktem końcowym jest zawsze chlorkowy kompleks platyny(II).

3

Kinetics and Mechanism of the Redox Reaction Between Pt(IV) Chloride Complex Ions and Sodium Thiosulfate in Aqueous Solution. Part I: Acidic Solution

Pacławski K., Piwowońska J.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1413--1420

EN

In this work, spectrophotometric studies of the kinetics and mechanism of reaction between [PtCl4]2- complex ions and sodium thiosulfate, were carried out. The influence of different conditions, such as: initial concentrations of reductant and platinum(IV) complex ions, ionic strength, pH and temperature on the rate constant, was experimentally determined. From the obtained results, the molecularity of the first elementary step, value of the enthalpy and entropy of activation in Eyring equation as well as corresponding rate equation, were experimentally determined. It was found that the reaction is relatively slow and leads to the S, Pt and PtS colloids formation. The best conditions for solid phase formation containing Pt are at pH = 5.

PL

W pracy przedstawiono wyniki badań spektrofotometrycznych kinetyki i mechanizmu reakcji jonów kompleksowych [PtCl4]2- z tiosiarczanem sodu. Doświadczalnie określono wpływ różnych czynników na stałą szybkości reakcji, tj.: stężenia początkowego reagentów, siły jonowej, pH oraz temperatury. Na podstawie otrzymanych wyników wyznaczono cząsteczkowość pierwszego etapu elementarnego reakcji, wartości entalpii i entropii aktywacji reakcji oraz równanie kinetyczne. Wykazano, że reakcja jest stosunkowo wolna i prowadzi do powstania koloidu złożonego z siarki, platyny oraz siarczku platyny (PtS). Najlepsze warunki do wytrącania koloidu zawierającego Pt to pH = 5.

4

Spectroscopic Studies of Platinum Complexes with 6-Mercaptopurine-9-D-riboside

Łakomska I.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 10

1717-1724

EN

The reaction of 6-mercaptopurine-9-D-riboside (6-mpr) with K2PtCl4 and K2PtCl6 has been studied. The obtained complexes: Pt(6-mpr)26H2O(1a) andPtCl2(6-mpr)2CH3OH(2) have been characterized by elemental analysis, thermogravimetry, IR and multinuclear NMR (1H, 13C, 15N). Spectroscopic studies suggest that compounds (1a, 2) contain monodeprotonated ligands, which bind to platinum ion via S(6) and N(7). Far-IR spectra indicate the square-planar geometry for (1a) and octahedral geometry for (2).