An X-ray absorption spectroscopy investigation of the coordination environment of electrogenerated Ni(ii)-pseudohalide complexes arising from the anodic polarization of Ni electrodes in DMSO solutions of NCO⁻, NCS⁻and NCSe⁻ions

Abstract

EXAFS/XANES measurements combined with IR spectroelectrochemistry directly probe in situ the coordination sphere of electrogenerated ions in metal electrode systems so obviating the need to isolate ions unchanged from the electrolyte for analysis.

A Combined SNIFTIRS and XANES Study of Electrically Polarized Copper Electrodes in DMSO and DMF Solutions of Cyanate (NCO−), Thiocyanate (NCS−) and Selenocyanate (NCSe−) Ions

“…This was confirmed in later published X-ray absorption spectroscopy (XAS) results. 24 Similar in situ IR spectroscopy work from our laboratory on the Au/pseudohalide systems in DMF and DMSO showed the predominance of the Au(I) oxidation state in the electrochemically generated products detected. 23 The aim of the present study is hence to better understand the polarization behavior and speciation of copper electrodes in non-aqueous, polar aprotic solvents, i.e.…”

“…These products may be dissolved solution or gaseous species and electrodeposited solids on the electrodes. We have used a similar suite of techniques as in the earlier studies of Ni electrodes anodically polarized in pseudohalide-containing DMSO or DMF electrolytes, 13,24 namely in situ IR spectroelectrochemical methods combined with synchrotron X-ray absorption near edge spectroscopy (XANES). A study was undertaken both of cell solutions containing electrogenerated products, and model solutions prepared that mimic these species independently of the electrolysis process.…”

Synthesis of magnetic nanoparticles with an IDA or TED modified surface for purification and immobilization of poly-histidine tagged proteins

“…In general, Ni(II) ions has six coordination sites. 64,65 Aer chelation, the number of remaining sites were reduced to three for IDA and one for TED, which contributed to the difference of binding characteristics between his-tagged proteins and Ni-MNPs. [66][67][68] De Goes et al stated that "the more polydentate the chelating ligand is, the better the stability of chelate complex, the lower the metal ion leakage, and the higher the selectivity, but on the other hand, the lower the capacity for protein adsorption".…”

A fundamental in situ IR spectroelectrochemical study of the electrical polarization of nickel, copper and gold electrodes in the presence of the unstable tellurocyanate ion in DMSO and DMF solutions

“…When present as an adatom on the surface, the Te was found not to catalyse CO oxidation because the adatom always existed in its reduced form on the electrode and hence could not transfer oxygen to effect the oxidation. [5][6][7] The successful preparation of the TeCN À ion, an inherently unstable ion, was reported in 1968 by Downs,8 who prepared it from the reaction of tetraethylammonium cyanide and elemental Te in DMF and isolated pale yellow crystals that were highly moisture and oxygen sensitive. 2,3 In other studies, technologically valuable lms, such as cadmium telluride thin lms, have been prepared by electrodeposition of Te on a Au electrode followed by reduction with metal ions present.…”

“…related pseudohalide ions of cyanate (NCO À ), thiocyanate (NCS À ) and selenocyanate (NCSe À ), have been subjected to previous IR spectroelectrochemical investigations in aqueous and polar aprotic solvents. [5][6][7] The successful preparation of the TeCN À ion, an inherently unstable ion, was reported in 1968 by Downs,8 who prepared it from the reaction of tetraethylammonium cyanide and elemental Te in DMF and isolated pale yellow crystals that were highly moisture and oxygen sensitive. A Raman spectrum of a solution of the ion showed a peak at 2080 cm À1 .…”