CuCl2 Complex Research Articles

(CAAC)CuCl: A Competent Precatalyst for Carbonyl and Ester Hydrosilylation.

Cu-catalyzed carbonyl hydrosilylation involves a ligated "[(L)CuH]" as the active catalyst, where the ligand L has a crucial role toward the stability, stereoselectivity, and enhancement of the hydridicity. Strongly σ-donating N-heterocyclic carbenes (NHCs), their ring-expanded form, and an abnormal NHC as ligands have yielded robust and efficient Cu catalysts. However, cyclic(alkyl)(amino)carbenes (CAACs), despite being stronger σ-donors than NHCs and already having a salient Cu(I) chemistry, are yet to be reported as a similar ligand platform for this purpose. We establish here the familiar [(Me2CAAC)CuCl] as a powerful precatalyst in this regard. Additionally, it also catalyzes the more challenging ester hydrosilylation, which is a rare feat for a Cu catalyst. Apart from the stronger σ-donating ability, the more steric "openness" of CAACs than bulky NHCs also seems to be advantageous. To corroborate, three new (CAAC)CuCl complexes [(ArCH2,MeCAAC)CuCl] (Ar = Ph, 1-naphthyl, and 1-prenyl) are devised, where the effective steric around the copper is practically unaltered from the case of [(Me2CAAC)CuCl]. All three are equally active in carbonyl and ester hydrosilylation as [(Me2CAAC)CuCl]. Computation suggests the carbonyl insertion into a "(CAAC)Cu-H" as the rate-limiting step. To elucidate the involvement of a "(CAAC)CuH", "(PhCH2,MeCAAC)CuH" is generated in situ and is trapped as its BH3 adduct (PhCH2,MeCAAC)CuBH4.

Synthesis and Antiproliferative Activity of New Copper, Cobalt, and Zinc Complexes with Abiraterone Acetate

New complexes CuCl2[AbAc]2 (I), CoCl2[AbAc]2 (II), and ZnCl2[AbAc]2 (III) with abiraterone acetate (AbAc) are synthesized. The molecular structure of complex II is determined by X-ray diffraction (XRD) (CIF file CCDC no. 2252346). The cobalt atom coordinates with abiraterone acetate due to the N‑donor pyridine atom. The model processes of hydrolysis of the compounds in acidic and neutral media and their ability to interact with the superoxide radical anion generated in the xanthine–xanthine oxidase enzymatic system are studied. A high activity of complexes I and II is found. The MTT test shows that the antiproliferative activity of compounds I–III against the HCT-116, MCF-7, A-549, and WI-38 cells is comparable with the activity of cisplatin and exceeds that of the initial AbAc for the PC-3 cell line. Complex II also induces cell cycle arrest in the G0/G1 phase of RNA protein synthesis.

Smart Hydrogel Reactor of Poly(N-isopropylacrylamide)/Polyethylene Glycol Interpenetrating Polymer Networks for Oxidative Coupling of 2-Naphthol

AbstractHydrogels with an interpenetrating polymer network (IPN) structure composed of poly(N-isopropylacrylamide) (poly-NIPAM) gel and a gel containing polyethylene glycol (PEG) chains were synthesized. They showed a typical temperature-responsive volume change in water owing to the constructed poly-NIPAM gel component. Oxidative coupling of 2-naphthol with IPN cryogels and a conventional catalyst, the CuCl2 complex of N,N,N′,N′-tetramethylenediamine, was conducted in water under an O2 atmosphere; the IPN gel prepared from PEG with a larger molecular weight of 11000 afforded a product with a good yield of 73% (91% conv.) during the reaction in basic media. The hydrogel effectively promoted the reaction but hardly produced any product without the catalyst, acting as a reactor vessel in the water. Owing to the low durability of the PEG gel component for hydrolysis, a limitation was also suggested during experiments on the recyclability of the hydrogel.

Chalcocite Cu2S solubility in aqueous sulfide and chloride fluids. Thermodynamic properties of copper(I) aqueous species and copper transport in hydrothermal systems

The most important Cu reserves, including ores of porphyry deposits, were formed by Cl- and S-bearing hydrothermal fluids transporting and depositing metals within the magmatic-hydrothermal ore systems. In order to determine the state of Cu in the fluids, we measured the solubility of chalcocite Cu2S at 350 and 450 °C, 500 and 1000 bar. The concentration of H2S varied from 0.08 to 0.4 m [mol⋅(kg H2O)−1], NaOH – from 0 to 0.2 m, NaCl + HCl – from 0.01 to 4 m. The solubility of chalcocite can be described by the reactions:0.5 Cu2S(cr) + 0.5 H2S(aq) = CuHS(aq) log K°CuHS = −3.99 ± 0.07 (350 °C/500 bar)−4.61 ± 0.09 (450 °C/500 bar), −4.26 ± 0.11 (450 °C/1000 bar);0.5 Cu2S(cr) + 0.5 H2S(aq) + HS− = Cu(HS)2− log K°Cu(HS)2- = −0.85 ± 0.08 (350 °C/500 bar)−0.65 ± 0.11 (450 °C/1000 bar);0.5 Cu2S(cr) + HCl(aq) = CuCl(aq) + 0.5 H2S(aq) log K°CuCl = −3.11 ± 0.70 (450 °C/1000 bar);0.5 Cu2S(cr) + HCl(aq) + Cl− = CuCl2− + 0.5 H2S(aq) log K°CuCl2- = 0.33 ± 0.19 (450 °C/1000 bar)These results, together with data of Rubtsova et al. (2023) on the coupled solubility of Cu(cr) and Ag in chloride fluids, demonstrated that a simple extended Debye-Hückel equation describe activity coefficients of charged species at any NaCl concentration up to the solubility limit at near- and supercritical PT-parameters; activity coefficients of neutral species can be calculated with Setchenov parameter equal to zero. The Cu2S(cr) solubility in sulfide-chloride-bearing fluids is consistent with the formation of Cu-Cl complexes which implies that mixed Cu-HS-Cl complexes can be neglected. The experimental values pooled with the reliable literature data were fitted to the HKF (Helgeson-Kirkham-Flowers) model equation of state (EoS). The obtained HKF EoS parameters allow to predict thermodynamic properties of CuHS(aq), Cu(HS)2−, and CuCl(aq) from 25 to 700 °C and from Psat. to 2000 bar, and up to 1000 °C/5000 bar for CuCl2−. The AD (Akinfiev and Diamond) EoS parameters were derived for CuCl(aq). The AD EoS can be used to calculate the CuCl(aq) Gibbs free energy in the low-density fluids (ρH2O < 0.35 g⋅cm−3) up to 700 °C. The obtained thermodynamic data imply that CuCl2− predominates in high-density ore-forming fluids (ρH2O > 0.35 g⋅cm−3) of total chloride content >0.1 wt% up to the NaCl saturation limit. The hydrosulfide complexes are the main forms of Cu occurrence in the fluid with concentration of dissolved chlorides <0.1 wt% equilibrated with silicate mineral assemblages (e.g., K-feldspar-muscovite-quartz, pH is near-neutral). However, their concentration in the presence of Cu-bearing sulfides is low (< 0.5 ppm at 500 °C/1500 bar) and decreases with temperature decreasing.

Preparation, Characterization and Antimicrobial Activity of Pd(II), Zn(II) and Cu(II) Complexes of Benzimidazoles and Schiff Bases Including Ferrocene Group

PdCl2, ZnCl2 and CuCl2 complexes of three benzimidazole derivatives and two Schiff bases having the ferrocene group were synthesized and characterized. It was unexpectedly noticed that the Pd(II) and Zn(II) complexes exhibit paramagnetic characters corresponding to about one electron caused by the ferrocene moiety. For the same reason, the magnetic moment value of the Cu(II) complexes was also higher than the anticipated values. Besides, the antimicrobial activity of the complexes was investigated against six bacteria and three fungi. Comparing the ligands, the Schiff bases exhibited higher antimicrobial activity than the benzimidazole derivatives, especially on Gram+ bacteria. Among all compounds investigated in this work, [Zn(SB1)2]·2H2O showed the highest activity against S. epidermidis and S. aureus which are Gram+ bacteria.

Multiple reinforcement of chloride ion on oxidizing acetaminophen with zero-valent copper particles: In-site formation and catalysis of hydrogen peroxide

Zero-valent copper particles (Cu0) used to degrade pollutant due to its in-site generation and activation of hydrogen peroxide (H2O2), while the disproportionation of Cu+ limited the efficacy. In this study, spiking chloride ion (Cl−) into zero-valent copper (Cu0) system (Cl−/Cu0 system) enhanced greatly acetaminophen degradation. The addition of Cl− not only reduced the dismutation reaction of Cu+, but also helped the comproportionation reaction of Cu0 and Cu2+, leading to much generation of Cu+ and H2O2. Hydroxyl radical (OH) and reactive chlorine species were identified as the dominant reactive oxidants in the Cl−/Cu0 system with its contribution ratio of degrading acetaminophen being respectively 73.4 % and 23.8 %. In the Cl−/Cu0 system, Cu+ was released by H+ corrosion from Cu0, and then Cu+ coupled with Cl− forming Cu-Cl complexes; Meanwhile, the reaction of O2 and the species of Cu+ (e. g. Cu-Cl complexes and Cu+) produced H2O2 and, then the species of Cu+ catalyzed H2O2 to form OH; Thereinto, partial OH was shifted by Cl− to reactive chlorine species. Except for fulvic acid, coexisting substrates such as sulphate, nitrate and phosphate ions had no obvious inhibition impact on oxidizing acetaminophen in the Cl−/Cu0 system. Furthermore, the Cl−/Cu0 system presented a good removal rate of acetaminophen in three actual water samples. Moreover, three kinds of dyes and painkillers was removed over 78 % in the Cl−/Cu0 system. The residual total dissolved copper was under II-level of environmental quality standards for surface water in China by alkali precipitation and filtration after reaction. Therefore, the study provided a new idea to enhance Cu0 for the purification of pollutants.

Spectral studies, thermal investigations, and anticancer activity of some divalent metal complexes derived from 2‐(4‐bromophenylamino)acetohydrazide ligand

AbstractA series of biologically active metal complexes was yielded from the reactions of 2‐(4‐bromophenylamino)acetohydrazide ligand (HL) with Co(II), Ni(II), Cu(II), Cd(II) chlorides, CuBr2, Cu(CH3COO)2, and Cu(ClO4)2 salts. The structure and stereochemistry of the afforded complexes were elucidated by means of elemental analyses, molar conductance, magnetic susceptibility, thermal analyses (TG/DTG), and spectral techniques (mass, IR, UV‐Vis, and 1H NMR). Elemental analyses along with molar conductance data demonstrated that all metal complexes are nonelectrolyte and were formed with 1L:1M, 1L:2M, and 2L:1M stoichiometry. IR spectral data provided an evidence for the neutral bidentate behavior of the hydrazide ligand toward metal ions via carbonyl oxygen and amino nitrogen atoms (ON donor). Magnetic susceptibility along with electronic absorption spectral results authenticated that all complexes have an octahedral geometry except, CuCl2 complex (3), which possessed a square planar one. The hydrazide ligand and some of its synthesized metal complexes were screened in vitro for their antitumor and apoptotic activity. The results showed that CuBr2 complex (4) has promising anticancer activities against breast MCF7, liver HepG2, and colorectal HCT 116 cancerous cells through induction of proapoptotic gene (Bax) and inhibit the antiapoptotic gene (Bcl‐2), thus increase the Bax/Bcl‐2 ratio. Moreover, these newly synthesized compounds were most potent and can be used as a therapeutic chemoprevention against these cancerous cells compared with doxorubicin (DOX), the currently available anticancer drug against solid tumors.

Investigation of Polyvinyl Alcohol-CuS Compound with Metal-Like Conductivity

PVA-CuS compound produced from hybrid interpolymeric polyvinyl alcohol (PVA)-CuCl2 complex through solid state sulfurization was investigated by means of X-ray diffraction, UV-Vis and Raman spectroscopy, and direct current measurements. It is claimed that CuS in this compound has one-dimensional structure. This result is achieved by using a precursor technique based on diffusion limitation at solid state synthesis, so that the structure of initial reagents is inherited by reaction products. The produced material is determined to possess metal-type conductivity and thermopower in the vicinity of room temperature. Keywords: hybrid interpolymeric complexes, polyvinyl alcohol, CuS, inorganic polymers, one-dimensional structures, electrical properties.

Copper(I) Complexes of P‐Stereogenic Josiphos and Related Ligands

AbstractStarting from (R)‐Ugi's amine, diastereoselective lithiation followed by Ar'PCl2 and then Ar’’MgBr led to the generation, as single diastereoisomers, of (R,Sp,Sphos) [Ar’=Ph, Ar’’=o‐Tol] and (R,Sp,Rphos) [Ar’=o‐Tol, Ar’’=Ph] PPFA ligand derivatives. Amine substitution of both with HPCy2 gave P‐stereogenic Josiphos ligands, and then addition of CuCl, the corresponding copper(I) complexes. The latter were also generated by using borane P and N protecting groups and in situ Cu(I) complexation, avoiding the isolation of air‐sensitive phosphine intermediates. This protection methodology was also applied to the synthesis of Josiphos/CuCl complexes derived from PCl3. In addition, related bulky cobalt‐sandwich complex‐based derivatives were also obtained. Preliminary investigation revealed isolated CuCl complexes as competent catalyst precursors for enantioselective conjugate addition reactions.

Synthesis, structural characterization and antimicrobial activity of Schiff bases and benzimidazole derivatives and their complexes with CoCl2, PdCl2, CuCl2 and ZnCl2

In this study, new Schiff bases (H2L1 and H2L2) and benzimidazolylphenol derivatives (HL3 − HL5) derived from 5-chlorosalicylaldehyde and appropriate aminophenol and o-phenylenediamine derivatives including 4-methyl/4,5-dimethyl/4-chloro‑5-nitro groups were synthesized and characterized. CoCl2, PdCl2, CuCl2 and ZnCl2 complexes of the ligands were synthesized and characterized by using elemental analysis, molar conductivity, magnetic moment, FT-IR and NMR spectroscopy. In addition, the crystal structure of H2L1 and [Pd(L1)(CH3CN)]·H2O were determined by X-ray diffraction spectroscopy. Keto-enol tautomerism is observed in the Schiff base compounds according to spectral data. Antimicrobial activities of the compounds were tested toward six bacteria and three fungi. Some metal complexes (e.g. Co(II) complexes of the benzimidazole derivatives) showed higher activity towards the test microorganisms than the ligands. In addition, it is observed that the Co(II) complexes show in a wide range antimicrobial activity compared to the other complexes.

Synthesis, Characterization and Antimicrobial Activity of Schiff Bases Including Three Hydroxy Groups and Their CoCl2, PdCl2, CuCl2 and ZnCl2 Complexes

AbstractFour Schiff bases, (3/4/2/4)‐{[(2‐hydroxy‐5‐methylphenyl)imino]methyl}benzene‐1,2/1,3/1,4/1,2‐diols (H3L1‐H3L4), derived from 2,3/2,4/2,5/3,4‐dihydroxybenzaldehydes and 2‐amino‐4‐methylphenol, and their CoCl2, PdCl2, CuCl2 and ZnCl2 complexes were synthesized and characterized. The structures of the complexes were suggested on the basis of elemental analysis, TGA, molar conductivity, magnetic moment, FT‐IR, UV‐vis and NMR spectroscopy. According to the analytical and spectral data, the ligands H3L1, H3L2 and H3L3 acted as tridentate, giving chelate structures in the complexes, via the C=N nitrogen and two phenolate oxygen atoms whereas H3L4 acted as bidentate. In addition, the crystal structure of H3L1 was determined by X‐ray diffraction. The spectral data show that there is keto‐enol tautomerization in the ligands and keto form is dominant in H3L1 and H3L3 while enol form is in H3L2 and H3L4. Antimicrobial activities of the compounds were tested against six bacteria and three fungi. [Zn(H2L1)Cl]⋅4H2O showed superior activity toward the fungi C. albicans, C. parapsilosis and C. tropicalis compared to H3L1 and the other compounds. Strong activity of H3L1, H3L2 and H3L3 was observed toward S. aureus whereas they showed weak activity to the other microorganisms.

Cyto-genotoxic evaluation of novel anti-tubercular copper (II) complexes containing isoniazid-based ligands

Considering the promising previous results of Cu (II) complexes with isoniazid active ligand against Mycobacterium tuberculosis, the main causative agent of tuberculosis, novel biological assays evaluating its toxicogenic potential were performed to ensure the safe use. The genotoxicity/mutagenicity of the complexes CuCl2(INH)2.H2O (I1), Cu(NCS)2(INH)2.5H2O (I2) and Cu(NCO)2(INH)2.4H2O (I3) was evaluated by the Comet, Micronucleus-cytome and Salmonella microsome (Ames test) assays. The cell viability using resazurin assay indicated that I1, I2 e I3 had moderate to low capacity to reduce the viability of colorectal cells (Caco-2), liver cells (HepG2), lung cells (GM 07492-A and A549) and endothelial cells (HU-VE-C). On genotoxicity/mutagenicity, I1 complex did not induce sizable levels of DNA damage in HepG2 cells (Comet assay), and gene (Ames test) and chromosomal (Micronucleus-cytome assay) mutations. Already, I2 and I3 complexes were considered mutagenic in the highest concentrations used. In light of the above, these results contribute to valuable data on the safe use of Cu(II) complexes. Considering the absence of mutagenicity and cytotoxicity of I1, this complex is a potential candidate for the development of a new drug to the treatment tuberculosis, while I2 and I3 require caution in its use.

Interaction of Zn(II) and Cu(II) with ε-poly-L-lysine and properties of the complexes

ε-Poly-L-lysine (ε-PL) is a natural food preservative with high safety to humans and a wide antimicrobial spectra. It was found that ε-PL could form precipitates when it contacted to Cu(II) and Zn(II). Thus in this study, two complexes of ZnCl2 and CuCl2 with ε-poly-L-lysine having molecular weights between 2 and 5 kDa were prepared and characterized by elemental analysis (EA), atom absorption spectrometry (AAS), chlorine assay, etc. The results show that the compositions of two complexes can be expressed as [ NH-(CH2)5-CO ] 2n•(ZnCl2)n•2nH2O and [ NH-(CH2)5-CO ] 2n•(CuCl2)n•2nH2O (n=6-18), respectively. The results of FT-IR reveal that the formation of Zn-N and Cu-N coordination bonds. X-RD patterns indicat that the two complexes are new phases different from the raw ε-PL material. On the basis of TG-DTA curves, the complexes have a coordination reaction. From the results of the bacteriostatic test, ε-PL-Zn(II) and ε-PL-Cu(II) have similar antibacterial activity to ligand ε-PL.

Copper complexation and solubility in high-temperature hydrothermal fluids: A combined study by Raman, X-ray fluorescence, and X-ray absorption spectroscopies and ab initio molecular dynamics simulations

Data for the solubility of CuS (reacting to Cu2S), Cu, and bornite + chalcopyrite + pyrite (reacting to Cu-Fe-S solid solution) in H2O + NaCl fluids were determined in situ using synchrotron-radiation X-ray fluorescence (SR-XRF) spectroscopy. The aqueous Cu concentrations ranged between 25 ppm at 500 °C, 320 MPa, 0.5 m NaCl and 760 ppm at 500 °C, 310 MPa, 4.78 m NaCl, increased with temperature along an isochore and with NaCl molality, and decreased with pressure. The X-ray absorption near edge structure (XANES) spectra of the fluid from dissolution of CuS or Cu in H2O + NaCl at 500 °C are nearly identical with published spectra of CuCl2−(aq), but differ significantly from reported spectra of Cu(I) in Cl-free hydrosulfide solutions.Raman spectra of H2O + HCl ± NaCl fluids reacted with CuS or, for comparison, metallic Cu were measured at temperatures to 600 °C and pressures to 2 GPa to test if this technique can provide additional information on the complexation of Cu(I) and on the solubility of copper in hydrothermal fluids. These spectra showed that CuCl2−(aq) was the most abundant Cu(I) species at all conditions. In addition, CuCl32−(aq) was observed at high HCl concentrations, but the Raman spectra provided no convincing evidence for Cu(I) complexation with H2S or S3− (HS−(aq) was below detection in these acidic fluids). Generally, there was an increase in the sum of the integrated intensities of the bands assigned to Cu complexes with increasing HCl concentration, and a decrease if sulfide was present. At all fluid compositions, the intensity of the Raman bands from CuCl stretching vibrations decreased with increasing pressure at constant temperature for single-phase fluids, without formation of additional bands. Based on ab initio modeling, the complexes CuCl2−(aq), Cu(HS)2−(aq), and Cu(HS)Cl−(aq) are not distinguishable by Raman spectroscopy, but the stretching vibration of Cu(I) complexes with H2S should occur at significantly lower wavenumbers.Overall, the results indicate that Cu(I) is transported predominantly as CuCl2−(aq) in reducing sulfur-free or H2S ± S3−-bearing chloridic hydrothermal fluids. The decrease in the Cu solubility in H2O + HCl ± NaCl ± H2S fluids with increasing pressure without a detectable change in speciation is caused by decrease in the formation constant of CuCl2−(aq) with pressure. Changes in the copper speciation and depressurization can be ruled out as causes for hydrothermal copper ore formation at high fluid densities above the critical density. At this condition, copper ore may precipitate by dilution, cooling in the presence of H2S, increase in pH, and/or an increase in the H2S activity.

The Synthesis of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polymethylmethacrylate Alloy in Aqueous Medium via a One-Pot Method

An environmentally friendly one-pot synthetic method based on green chemistry was developed to prepare thermodynamically partially compatible poly(2,6-dimethyl-1,4-phenylene oxide)/poly(methylmethacrylate) (PPO/PMMA) alloy in water. The oxidative polymerization of 2,6-dimethylphenol in alkaline aqueous solution was firstly conducted and then methyl methacrylate (MMA) was added into the reactor before the end of polymerization. MMA could penetrate into PPO particles and then in situ reverse atom transfer radical polymerization (RATRP) of methyl methacrylate was initiated by 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride after the oxidative polymerization. Both the oxidative polymerization of 2,6-dimethylphenol and RATRP of methyl methacrylate were catalyzed by the complex of CuCl2 and 4-dimethylaminopyridine. Finally, thermodynamically partially compatible PPO/PMMA alloy was successfully prepared which possessed a multi-layer core-shell structure with two polymers embedded in each other.

Petrography and Mineral Chemistry of Magmatic and Hydrothermal Biotite in Porphyry Copper-Gold Deposits: A Tool for Understanding Mineralizing Fluid Compositional Changes During Alteration Processes

DOI: 10.17014/ijog.5.1.47-64This study aims to understand the petrography and chemistry of both magmatic and hydrothermal biotites in porphyry copper-gold deposits, and to evaluate the fluid compositional changes during alteration processes. A total of 206 biotite grains from selected rock samples taken from the Batu Hijau porphyry Cu-Au deposit was analyzed. Detailed petrography and biotite chemistry analysis were performed on thin sections and polished thin sections, respectively, representing various rocks and alteration types. A JEOL JXA-8900R electron microprobe analyzer (EMPA) was used for the chemistry analysis. The biotite is texturally divided into magmatic and hydrothermal types. Ti, Fe, and F contents can be used to distinguish the two biotite types chemically. Some oxide and halogen contents of biotite from various rocks and alteration types demonstrate a systematic variation in chemical composition. Biotite halogen chemistry shows a systematic increase in log (XCl/XOH) and decrease in log (XF/XOH) values from biotite (potassic) through chlorite-sericite (intermediate argillic) to actinolite (inner propylitic) zones. The y-intercepts on the log (XCl/XOH) vs. XMg and log (XF/XOH) vs. XFe plotted for biotite from potassic and intermediate argillic zones are similar or slightly different. In contrast, the y-intercepts on the log (XCl/XOH) vs. XMg and log (XF/XOH) vs. XFe plotted for biotite from inner propylitic zone display different values in comparison to the two alteration zones. Halogen (F,Cl) fugacity ratios in biotite show a similar pattern: in the potassic and intermediate argillic zones they show little variation, whereas in the inner propylitic zone they are distinctly different. These features suggest the hydrothermal fluid composition remained fairly constant in the inner part of the deposit during the potassic and intermediate argillic alteration events, but changed significantly towards the outer part affected by inner propylitic alteration. High halogen content, particularly Cl, in hydrothermal biotite may portray that copper and gold were transported in mineralizing fluids in the form of chloride complexes CuCl2- and AuCl2-, respectively.

The first water‐soluble copper(I) complexes bearing sulfonated imidazole‐ and benzimidazole‐derived N‐heterocyclic carbenes: Synthesis and anticancer studies

The first water‐soluble bis(NHCSO3)CuCl complexes (NHCSO3 = NaImBn,PrSO3, Na2(4‐Me)ImPrSO3 and Na2BzImPrSO3) derived from the sulfonated N‐heterocyclic carbene precursors HImBn,PrSO3 (3‐(1‐benzyl‐1H‐imidazol‐3‐ium‐3‐yl)propane‐1‐sulfonate), Na(4‐Me)HImPrSO3 (sodium 3,3′‐(4‐methyl‐1H‐imidazole‐3‐ium‐1,3‐diyl)dipropane‐1‐sulfonate) and NaHBzImPrSO3 (sodium 3,3′‐(1H‐benzoimidazole‐3‐ium‐1,3‐diyl)dipropane‐1‐sulfonate) have been synthesized. These compounds have been characterized using infrared and NMR spectroscopy and electrospray ionization mass spectrometry. The in vitro anti‐tumour effects of the bis(NHCSO3)CuCl complexes and the corresponding free ligands were evaluated for a panel of various human tumour cell lines, including examples of lung, colon, ovarian and cervical carcinoma as well as of melanoma. Their cytotoxic properties were also evaluated against non‐transformed human cells and on a cellular model of cisplatin resistance. NHC–copper complexes induced cell killing effects preferentially against tumour cells, with IC50 values in the micromolar range. Additionally, they were found able to overcome acquired cisplatin resistance.

Paramagnetic CuII complexes with 1-(hetarylmethyl)silatranes

The structures of paramagnetic complexes CuCl2•L with L = HetCH2Si(OCH2CH2)3N [Het = pyrrol-1-yl (1), indol-1-yl (2), carbazol-9-yl (3), imidazole-1-yl (4), 3,5-dimethylpyrazol-1-yl (5), 1,2,4-triazol-1-yl (6), benzimidazol-1-yl (7), and 1,2,3-benzotriazol-1-yl (8)] were studied by the ESR and quantum chemical methods in terms of the density functional theory (DFT) approximation. The difference in structures of complexes CuCl2•1—CuCl2•8 is mainly determined by the nature of the five-membered heterocycle. The ESR spectra at room temperature are typical of the mononuclear complexes of CuII of axial symmetry with various types of distortions. In complexes CuCl2•1—CuCl2•3, narrow symmetric signals of zero-valent copper are recorded. These signals remain in the spectra for at least six months, which can characterize them as efficient stabilizing matrices of nanoparticles.

The effect of chloride ions on the electrochemical dissolution of chalcopyrite in sulfuric acid solutions

The dissolution of chalcopyrite in 0.2M sulfuric acid solutions with different sodium chloride concentrations was investigated. Different anodic potentials were applied, and the behavior of the electrode was observed using potentiodynamic, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. The results showed that the chalcopyrite open circuit potential (OCP, approximately 245mV vs. SCE) decreased as the NaCl concentration increased. Four different surface conditions emerged on the chalcopyrite surface as the anodic potentials increased: (1) a Cu1−xFe1−yS2 passive layer formed at OCP–500mV; (2) a second passive layer (Cu1−x-zS2) formed at 500–700mV (electrolyte without NaCl) or 500–800mV (electrolyte with NaCl); and (3) chalcopyrite was in an active area at 700–800mV (electrolyte without NaCl) or 800–900mV (electrolyte with NaCl), and all the previous passive layers disappeared. In this case, SO42− or S2O32− and S4O62− for the electrolyte without NaCl or with NaCl, respectively, are the oxidized forms of sulfide sulfur; (4) when the potential is above 800mV (for the electrolyte without NaCl) or 900mV (for the electrolyte with NaCl), pseudo-passive CuS is formed. Subsequently, the sulfur of CuS was oxidized to SO42−, and Cu2+ changed into CuCl+ with a NaCl concentration of 0mol/L and 0.5mol/L, respectively. However, a new passive layer(s) of Cu2(OH)3Cl formed with NaCl concentrations above 0.5mol/L. Overall, the results revealed that Cl− ions are advantageous for chalcopyrite dissolution. However, the oxidation of chalcopyrite generated chloride and cupric ions that can form the cuprous complexes CuCl0, CuCl2− or CuCl32−, which dramatically inhibit the on-going dissolution of chalcopyrite. EIS data confirmed that a high concentration of Cl− ions was not essential for chalcopyrite dissolution under the present conditions. Moreover, the critical Cl− ion concentrations were different for the four distinct potential areas outlined above, namely, 1.0mol/L, 1.25mol/L, 1.25mol/L and 0.5mol/L, respectively.

Ligand‐Controlled Regiodivergent and Enantioselective Copper‐Catalyzed Hydroallylation of Alkynes

AbstractA ligand‐controlled regiodivergent and enantioselective copper‐catalyzed intermolecular hydroallylation of alkynes with allylic phosphates and hydrosilanes has been achieved for the first time. The chiral bidentate sulfonate‐containing N‐heterocyclic carbene ligated CuCl complex leads to enantioenriched SN2′‐type products, whereas the use of the IMesCuCl catalyst affords SN2‐type products. Thus a range of chiral branched and achiral linear 1,4‐dienes could be facilely synthesized from readily available alkynes in a regiodivergent manner.