Stabilization of Copper(II) Thiosulfonate Coordination Complexes Through Cooperative Hydrogen Bonding Interactions

Abstract

A series of copper(II) thiosulfonate complexes have been prepared via the reaction of [Cu(Me 3tren)(OH 2)](ClO 4) 2 (Me 3tren = tris(2-methylaminoethyl)amine) with three thiosulfonate ligands (RSO 2S (-), where R = Me, Ph, and MePh) and characterized by microanalysis, FTIR spectroscopy, and X-ray crystallography. In these complexes, the distorted trigonal bipyramidal copper(II) coordination sphere is occupied by four amine nitrogen atoms from the tripodal tetramine ligand and an apically bound sulfur atom from the thiosulfonate ligand. By using the tripodal tetramine ligand the oxidation of the thiosulfonate has been restricted, allowing the isolation of the complexes. The Cu-S distances were found to be similar to those in related thiosulfate complexes, indicating coordinative interactions of similar strength. Two types of intramolecular hydrogen bonding interactions were evident which enhance the binding of the thiosulfonate to the copper(II) center. These interactions, which involve two amine N-H groups and either one or two thiosulfonate oxygens, were found to be weaker than in the corresponding thiosulfate complexes. The complex formation constants for the thiosulfonate complexes (log K f = 0.3-0.7) were found to be two orders of magnitude lower than compared to the thiosulfate analogues. This correlates well with a lower strength of intramolecular hydrogen bonding.

Distortional Isomerism in Copper(II) Nitrato Complexes of N,N′,N″‐Tris{[(para‐nitrobenzyl)phenyl]aminoethyl}amine

“…[1] This open coordination site has often been used in the stabilization of highly reactive species, such as copper-dioxygen complexes, [2,3] or the stabilization of redox-active anions, such as thiosulfates and thiosulfonates. [4] Copper(II) is sometimes found to adopt different geometries with the same ligand due to the "plasticity" of the copper(II) ion. [5,6] Distortion isomers have been reported, which have distinctly different colours arising from only slight distortions in the coordination sphere of the copper(II) ion, [6,7] and, in some cases, distortion isomers have been isolated as differently solvated species.…”

“…[5,6] Distortion isomers have been reported, which have distinctly different colours arising from only slight distortions in the coordination sphere of the copper(II) ion, [6,7] and, in some cases, distortion isomers have been isolated as differently solvated species. [8] We recently reported that the [Cu(p-NO 2 BP) 3 trenF]BF 4 complex can be formed by reaction of a tren-based ligand, (p-NO 2 BP) 3 tren, with Cu(BF 4 ) 2 ·6H 2 O. The fluoride ligand can be generated from the hydrolysis of a BF 4 -anion or introduced by the addition of a fluoride salt.…”

“…[8] We recently reported that the [Cu(p-NO 2 BP) 3 trenF]BF 4 complex can be formed by reaction of a tren-based ligand, (p-NO 2 BP) 3 tren, with Cu(BF 4 ) 2 ·6H 2 O. The fluoride ligand can be generated from the hydrolysis of a BF 4 -anion or introduced by the addition of a fluoride salt. Analysis of the structure of this compound revealed the shortest ever reported Cu II -F distance, indicating very strong binding of fluoride to the Cu II centre.…”

Pitting Corrosion Mechanism of Alloy 800 in Simulated Crevice Chemistries Containing Thiosulfate

“…[51][52][53] However, the interaction between S 2 O 3 2¹ with Co, Cr, Fe and Ni is still unknown. Therefore, in our experiments, UV-Visible spectrometry was used to study the interaction of S 2 O 3 2¹ with the Cr, Fe, Ni, Cu and Co which is the composition metallic elements in Alloy 800 (see Table 2).…”

“…Spiccia's group studied the copper (II) thiosulfonate coordination complexes, which indicated this possibility. 51,53 Since the material studied in this project contains 0.02 mass%, the S 2 O 3 2¹ may interact with Cu in two ways and initiate the pitting corrosion. The 1st way is to form the coordinates of S 2 O 3 2¹ and Cu(II), as shown in Reactions 3 and 4…”