Zur Stabilität von Pd^II‐, Au^III‐ und Hg^II‐Komplexen mit N‐Acyl‐thioharnstoffen in Lösung

Abstract

Stabilitätskonstanten der PdII‐, AuIII ‐und HgII‐Komplexe mit 3 N‐Acyl‐thioharnstoffen werden pH‐potentiometrisch unter Zuhilfenahme von Austauschgleichgewichten in 75 Vol.‐% Dioxan/Wassermischung und in rein wäßriger Lösung bestimmt. Die Stabilitäten der Komplexe sind sehr hoch (lgβm>30) und ergeben die Reihenfolge AuIII≥PdII>HgII. Die Gold(III)‐Komplexe können leicht zu Gold(I)‐Komplexen reduziert werden. Mehrere Metallkomplexe wurden in fester Form dargestellt und charakterisiert.

Extraction and transport of gold(III) using some acyl(aroyl)thiourea ligands and a crystal structure of one of the complexes

“…We can only assume that the formation constants of the metal-ligand complexes were very high, being difficult for the metal ion to be stripped into the aqueous receiving phase using the pH gradient method. Indeed, this assumption is supported by an article by Hoyer et al [15], where they determined the formation constants of Au(III) with a number of N-acyl thioureas. They report log b m values in excess of 30.…”

Trinuclear CoIILnIIICoII Complexes (Ln = La, Ce, Nd, Sm, Gd, Dy, Er, and Yb) with 2,6-Dipicolinoylbis(N,N-diethylthiourea): Synthesis, Structures, and Magnetism

“…The coordination chemistry of transition metals with N , N -dialkyl- N ′-acylthioureas ( 1 ; Chart ) has constantly been studied in the last decades. − Most of the structurally characterized compounds with these ligands are mononuclear complexes of nickel­(II), palladium­(II), platinum­(II), or copper­(II) with a cis square-planar coordination mode ( 2 ; Chart ), in which the ligands commonly act as bidentate, monoanionic chelators. − Facial coordination of the ligands is observed in mononuclear octahedral complexes with technetium­(III) or cobalt­(III) ( 3 ; Chart ). − …”

“…In order to extend the coordination abilities of 4, the introduction of an additional donor atom by replacing the central m-phenylene ring by a 2,6-disubstituted pyridine ring was first reported by Schroder et al 28 The resulting 2,6dipicolinoylbis(N,N-alkylthiourea) (5) forms a polymeric silver(I) complex. 28 More interestingly, some series of trinuclear heterometallic complexes (6) with this ligand have been published recently. 25,29 The central metal ions in such complexes could be varied in a wide range, and products with alkali, alkaline-earth-metal, or lanthanide ions have been isolated and structurally characterized.…”