Tetrachloridocuprates(II)-synthesis and electron paramagnetic resonance (EPR) spectroscopy

Bright Blue Emitting Cu-Doped Cs2ZnCl4 Colloidal Nanocrystals

We report here the synthesis of undoped and Cu-doped Cs₂ZnCl₄ nanocrystals (NCs) in which we could tune the concentration of Cu from 0.7 to 7.5%. Cs₂ZnCl₄ has a wide band gap (4.8 eV), and its crystal structure is composed of isolated ZnCl₄ tetrahedra surrounded by Cs⁺ cations. According to our electron paramagnetic resonance analysis, in 0.7 and 2.1% Cu-doped NCs the Cu ions were present in the +1 oxidation state only, while in NCs at higher Cu concentrations we could detect Cu(II) ions (isovalently substituting the Zn(II) ions). The undoped Cs₂ZnCl₄ NCs were non emissive, while the Cu-doped samples had a bright intragap photoluminescence (PL) at ∼2.6 eV mediated by band-edge absorption. Interestingly, the PL quantum yield was maximum (∼55%) for the samples with a low Cu concentration ([Cu] ≤ 2.1%), and it systematically decreased when further increasing the concentration of Cu, reaching 15% for the NCs with the highest doping level ([Cu] = 7.5%). The same (∼2.55 eV) emission band was detected under X-ray excitation. Our density functional theory calculations indicated that the PL emission could be ascribed only to Cu(I) ions: these ions promote the formation of trapped excitons, through which an efficient emission takes place. Overall, these Cu-doped Cs₂ZnCl₄ NCs, with their high photo- and radio-luminescence emission in the blue spectral region that is free from reabsorption, are particularly suitable for applications in ionizing radiation detection.

Evidence of promising biological-pharmacological activities of the sertraline-based copper complex: (SerH2)2[CuCl4]

In the current study the ability of copper complex to exert multiple biological activities is combined with the pharmacological action of sertraline (SerH₂Cl, antidepressant drug). The hydrated and anhydrous forms of the tetrachlorocuprate(II) salts, namely (SerH₂)₂[CuCl₄]·½H₂O and (SerH₂)₂[CuCl₄], were synthesized and characterized by physicochemical methods. The crystal structures were determined by X-ray diffraction methods. The hydrate complex crystallizes in the monoclinic P2₁ space group with a=8.0807(2) Å, b=36.2781(8) Å, c=12.6576(3) Å, β=95.665(2)°, and Z=4 molecules per unit cell and the un-hydrate in P2₁ with a=13.8727(6) Å, b=7.5090(3) Å, c=18.618(1) Å, β=104.563(6)°, and Z=2. It has been suggested that Cu(II) ions might be critical in the development of mood disorders, showed potent biocidal activity, and also acted as analgesic adjuvant. To improve sertraline efficiency, the antidepressant and analgesic activities of the complex have been assessed in rats denoting a marked synergistic effect. Antithyroid and antimicrobial activities were also evaluated. Because depressive disorders and hyperthyroidism diseases led to an oxidative stress state, antioxidant capability has also been tested. The complex behaved as a good superoxide radical scavenger (IC₅₀=6.3×10^-6M). The ability of the complex to act as bromoperoxidase mimic was assessed. A pseudo-first order constant of k=0.157±0.007min^-1 has been determined. The complex evidences promising biological-pharmacological activities and the albumin binding studies showed a K_b of 2.90×10³M^-1 showing an improvement in the uptake of sertraline by albumin at 8h incubation (time required for effective interaction of sertraline with the protein).

Tetrabromidocuprates(II)-Synthesis, Structure and EPR

Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g‖ and g⊥) of the tensors could be determined and information on the structural changes in the [CuBr₄](2-) anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.

Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties

Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.

Catalytic catechol oxidation by copper complexes: development of a structure–activity relationship

High activity for the catalytic oxidation of 3,5-di-tert-butylcatechol was achieved with complexes of ligands that stabilize the biomimetic Cu^II μ-thiolate complex, hinting at a similarity with the required Cu-oxo intermediates.