Spectrophotometric study of copper(II) chloride-trimethyl phosphate solutions. Thermodynamic and spectroscopic properties of copper(II) chloro complexes in nonaqueous solutions

Abstract

Copper(II) chloride complexes were investigated spectrophotometrically in trimethyl phosphate solutions. A large set of UV, visible, and near-IR optical density values were computed in the numerical treatment involving least-squares and Marquardt methods. Stability and individual electronic spectra were calculated for several different theoretical models. Four mononuclear chloro complexes are the best representation of the constitution of the trimethyl phosphate solutions, and their overall formation constants are respectively log ß = 7.3, log ß2 = 12.4, log ß2 = 16.8, and log ß4 = 19.4. Quantitative data obtained for the chlorocuprates in terms of equilibrium constants and extinction coefficients are compared to those we have calculated earlier in six aprotic dipolar solvents. The solvation properties of the copper(II) chloride compounds were generalized by considering both the stability and the electronic spectra of the individual copper(II) chloro complexes. The stabilization of the chlorocuprates in solution is an inverse function of the donor numbers of the solvents. The calculated electronic spectra in these six solvents render it possible to classify the complexes into two groups: the cationic and neutral species for which an original crystal field parameter sequence is found; the anionic species for which the spectra demonstrate less solvation than for the cations. The d-d transition bands indicate configurational changes of copper(II), which is square planar in the cationic and neutral species and flattened tetrahedral in CuCl42", characterized in these nonaqueous media.

Electrochemical Behavior and Electronucleation of Copper Nanoparticles from CuCl2·2H2O Using a Choline Chloride-Urea Eutectic Mixture

“…This phenomenon is able to be recorded by UV-Vis spectra as shown in Figure 1. It reveals two peaks in the UV region, at 246 nm and 298 nm, which can be assigned to the presence of species such as [CuCl 4 ] 2- [25]. Meanwhile, in the near infrared (NIR) region, a broader peak between from 705 to 755 nm and a sharp peak at 1022 nm are detected, which can be due to the presence of [Cu(H 2 O) 6 ] 2+ species [26].…”

Insights into the Properties of Deep Eutectic Solvent Based on Reline for Ga-Controllable CIGS Solar Cell in One-Step Electrodeposition

“…These absorption bands can be attributed to the [CuCl 4 ] 2− complex. 25,26 Because light is absorbed in the blue spectral region, this absorption band is responsible for the typical yellow color of [CuCl 4 ] 2− solutions. With increasing time of stirring, the peak at 386 nm decreases in intensity and the main peak at 275 nm shifts to blue, a color change which occurred when Cu 2+ combined with a stronger ligand, thus causing a larger orbit splitting energy.…”

Spectroscopic insights leading to a better understanding of site-isolation in heterogeneous nanocatalysts

“…The component at 9900 cm -1 is possibly due to the Cu d-d transition of tetrahedral Cu II O4 species where the Clions are located at the apex of CuO4Cl square-based pyramids of the framework. 41 The absorptions decrease in intensity with the amount of Pt precursor (see also Figure SI-5), whilst a component at 22000 cm -1 becomes more pronounced when the Pt loading is increased (inset of Figure 2). This absorption is related to the CT Pt II -Cl of the square planar [PtCl4] 2units.…”

“…Bands at 41500, 35300 and 27000 cm -1 , here assigned to metal ligand charge transfer (CT) between Cu II and Cl atoms belonging to the [CuCl4] 2ions in the framework are observed (Figure 2). 41 In addition, the broad and complex absorptions at low energy are involving the d-d electronic transitions of Cu II species. More in detail, the band at 11850 cm -1 can be ascribed to the d-d transition of the [CuCl4] 2ions where the Cu II exhibits a square planar configuration (D4h symmetry).…”

“…More in detail, the band at 11850 cm -1 can be ascribed to the d-d transition of the [CuCl4] 2ions where the Cu II exhibits a square planar configuration (D4h symmetry). 41 These species are embedded within the 1D channels of the framework. The component at 9900 cm -1 is possibly due to the Cu d-d transition of tetrahedral Cu II O4 species where the Clions are located at the apex of CuO4Cl square-based pyramids of the framework.…”