Divalent Nickel Ions Research Articles

Efficacious adsorption of divalent nickel ions over sodium alginate-g-poly(acrylamide)/hydrolyzed Luffa cylindrica-CoFe2O4 bionanocomposite hydrogel

Existing Ni2+ heavy metal ions in an aqueous medium are highly hazardous for living organisms and humans. Therefore, designing low-cost adsorbents with enhanced effectiveness is essential for removing nickel ions to safeguard public health. In this study, a novel green nanocomposite hydrogel was synthesized through the free radical solution and bulk polymerization method, and its capability to remove divalent nickel ions from aqueous media was examined. The bionanocomposite hydrogel named as SA-g-poly(AAm)/HL-CoFe2O4 was produced by grafting polyacrylamide (AAm) onto sodium alginate (SA) in the presence of a magnetic composite recognized as HL-CoFe2O4, where HL represents hydrolyzed Luffa Cylindrica. By employing FT-IR, XRD, VSM, SEM, EDX-Map, BET, DLS, HPLC, and TGA techniques, morphological evaluation and characterization of the adsorbents were carried out. The performance of the adsorption process was studied under varying operational conditions including pH, temperature, contact duration, initial concentration of pollutant ions, and adsorbent dosage. HPLC analysis proved the non-toxic structure of the bionanocomposite hydrogel. The number of unreacted acrylamide monomers within the hydrogel matrix was measured at 20.82 mg/kg. The optimum conditions was discovered to be pH = 6, room temperature, adsorbent dosage of 1 of g.L−1, initial Ni2+ concentration of 10 mg.L−1, and contact time of 100 min, and the maximum adsorption efficiency at optimal state was calculated as 70.09, 90.25, and 93.83 % for SA-g-poly (AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples, respectively. Langmuir isotherm model was in good agreement with the experimental data and the maximum adsorption capacity of SA-g-poly(AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples was calculated to be 31.37, 43.15, and 45.19 mg.g−1, respectively. The adsorption process, according to kinetic studies, follows a pseudo-second-order kinetic model. Investigations on thermodynamics also demonstrated that the process is exothermic and spontaneous. Exploring the interference effect of co-existing ions showed that the adsorption efficiency has decreased with concentration enhancement of Ca2+ and Na+ cations in aqueous medium. Furthermore, the adsorption/desorption assessments revealed that after 8 consecutive cycles, there had been no noticeable decline in the adsorption effectiveness. Finally, actual wastewater treatment outcomes demonstrated that the bionanocomposite hydrogel successfully removes heavy metal pollutants from shipbuilding industry effluent. Therefore, the findings revealed that the newly fabricated bionanocomposite hydrogel is an efficient, cost-effective, easy-separable, and green adsorbent that could be potentially utilized to remove divalent nickel ions from wastewater.

Study of Optical Properties of Non Stoichiometric Nickel Oxide

In order to create non-stoichiometric nickel oxide, the precursor was thermally decomposed at various sintering temperatures up to 1100 °C. Structure of synthesis compound was characterization by X-ray diffraction method along with ritvield refinement. In UV-visible spectroscopy the band gap of the non-stoichiometric nickel oxide due to excitation of electrons can be obtained. The presence of Ni3+ ions in the oxide lattice shows charge transfer transition, with the consequent absorption in the visible region, which is mainly due to different ratio of Ni3+ and Ni2+ ions in the sample. These data were analysed, and it was discovered that by altering the decomposition temperature, the defects present in the non-stoichiometric get held up, causing neighbouring divalent nickel ions to become Ni3+ due to charge transfer process.

Improving electric-energy transmission performance of LixNi1-xO linear ceramic resistors by Li+/Ni3+ ion occupation regulation for pulsed power technology

Linear ceramic resistor receives extensive attention for its great advantages of fast energy transmission in pulsed power technology. However, the research about improving the linear current-voltage characteristics and pulsed charge-discharge speed of LixNi1-xO solid solution is rarely reported. Herein, we fabricated the LixNi1-xO linear ceramic resistors through a solid-phase reaction method, and the effects of the Li+ ion on the microstructure, current-voltage characteristics and pulsed charge-discharge properties were studied. Specifically, the electron holes exchange between divalent and trivalent nickel ions is enhanced by Li substitution, which contributed to the significantly decreasing in nonlinear coefficient (α) and resistivity. On a separate note, the rising edge of pulse charge-discharge is influenced by the linearity of LixNi1-xO ceramic resistors. The closer the nonlinear coefficient is to 1, the shorter the pulsed charge-discharge time is. Meanwhile, the defect dipoles induced by Li substitution may also contribute to the reduction of discharge time of LixNi1-xO linear ceramic resistors. As a result, the Li0.03Ni0.97O linear ceramic resistor with an excellent nonlinear coefficient of 1.03 exhibits extraordinary fast discharge speed (t0.9 = 94.8 ns) at 1.0 kV. The investigation on LixNi1-xO linear ceramic resistors suggests the potential of this material to be applied in the pulsed power system.

Reflectance spectroscopy as a promising tool for ‘sensing’ metals in hyperaccumulator plants

Main conclusionThe VNIR reflectance spectra of nickel hyperaccumulator plant leaves have spectral variations due to high nickel concentrations and this property could potentially be used for discovery of these plants. Hyperaccumulator plants accumulate high concentrations of certain metals, including manganese, cobalt, or nickel. Of these metals, the divalent ions of nickel have three absorption bands in the visible to near-infrared region which may cause variations in the spectral reflectance of nickel hyperaccumulator plant leaves, but this has not been investigated previously. In this shortproof-of-concept study, the spectral reflectance of eight different nickel hyperaccumulator plant species leaves were subjected to visible and near-infrared and shortwave infrared (VNIR-SWIR) reflectance spectrum measurements in dehydrated state, and for one species, it was also assessed in hydrated state. Nickel concentrations in the plant leaves were determined with other methods and then correlated to the spectral reflectance data. Spectral variations centred at 1000 ± 150 nm were observed and had R-values varying from 0.46 to 0.96 with nickel concentrations. The extremely high nickel concentrations in nickel hyperaccumulator leaves reshape their spectral reflectance features, and the electronic transition of nickel-ions directly contributes to absorption at ~ 1000 nm. Given that spectral variations are correlated with nickel concentrations it make VNIR-SWIR reflectance spectrometry a potential promising technique for discovery of hyperaccumulator plants, not only in the laboratory or herbarium, but also in the field using drone-based platforms. This is a preliminary study which we hope will instigate further detailed research on this topic to validate the findings and to explore possible applications.

Post‐Nickelation of a Crystalline Trinuclear Copper Organic Framework for Synergistic Photocatalytic Carbon Dioxide Conversion

AbstractRational regulation of electronic structures and functionalities of framework materials still remains challenging. Herein, reaction of 4,4′,4′′‐nitrilo‐tribenzhydrazide with tris(μ2‐4‐carboxaldehyde‐pyrazolato‐N,N′)‐tricopper (Cu3Py3) generates the crystalline copper organic framework USTB‐11(Cu). Post‐modification with divalent nickel ions affords the heterometallic framework USTB‐11(Cu,Ni). Powder X‐ray diffraction and theoretical simulations reveal their two‐dimensional hexagonal structure geometry. A series of advanced spectroscopic techniques disclose the mixed CuI/CuIIstate nature of Cu3Py3in USTB‐11(Cu,Ni) with a uniform bistable Cu34+(CuI2CuII) : Cu35+(CuICuII2) (ca. 1 : 3) oxidation state, resulting in a significantly improved formation efficiency of the charge‐separation state. This endows the Ni sites with enhanced activity and USTB‐11(Cu,Ni) with outstanding photocatalytic CO2to CO performance with a conversion rate of 22 130 μmol g−1 h−1and selectivity of 98 %.

Post-Nickelation of a Crystalline Trinuclear Copper Organic Framework for Synergistic Photocatalytic Carbon Dioxide Conversion.

Rational regulation of electronic structures and functionalities of framework materials still remains challenging. Herein, reaction of 4,4',4''-nitrilo-tribenzhydrazide with tris(μ2 -4-carboxaldehyde-pyrazolato-N,N')-tricopper (Cu3 Py3 ) generates the crystalline copper organic framework USTB-11(Cu). Post-modification with divalent nickel ions affords the heterometallic framework USTB-11(Cu,Ni). Powder X-ray diffraction and theoretical simulations reveal their two-dimensional hexagonal structure geometry. A series of advanced spectroscopic techniques disclose the mixed CuI /CuII state nature of Cu3 Py3 in USTB-11(Cu,Ni) with a uniform bistable Cu3 4+ (CuI 2 CuII ) : Cu3 5+ (CuI CuII 2 ) (ca. 1 : 3) oxidation state, resulting in a significantly improved formation efficiency of the charge-separation state. This endows the Ni sites with enhanced activity and USTB-11(Cu,Ni) with outstanding photocatalytic CO2 to CO performance with a conversion rate of 22 130 μmol g-1 h-1 and selectivity of 98 %.

Synthesis and Characterization of 5-Chloro 2-furaldehyde Thiosemicarbazone and Its Nickel, Copper and Zinc Complexes

The aim of the present study was to synthesize and characterize of divalent metal ions of Nickel, Copper and Zinc complexes of 5-chloro 2-furaldehyde thiosemicarbazone. Firstly ligand was prepared from the reaction between 5-Chloro-2-furaldehyde and thiosemicarbazide, the second step involved the synthesis of Ni(II), Cu(II) and Zn(II) complexes of 5-chloro 2-furaldehyde thiosemicarbazone. The prepared compounds (ligand or complex) was characterized using different analytical techniques such as elemental analysis, and IR, UV, Mass and 1H NMR tests, the results obtained showed that the ligand and its Ni(II), Cu(II), Zn(II) and Co(II) complexes of 5-chloro 2-furaldehyde thiosemicarbazone were prepared successfully.

Coagulation removal of nickel (II) ions by ferric chloride: Efficiency and mechanism.

Removal of heavy metal ions, in particular, divalent nickel ions from natural and wastewater, is of great importance for the environment. Nickel (II) ions are very toxic and provoke many diseases. The purpose of this work was to study the possibility of removing toxic nickel (II) ions from polluted water using an iron (III) chloride (FeCl3) coagulant. It is shown that the removal of nickel ions from aqueous solution by iron (III) hydroxide precipitate formed during the coagulation process at pH7 and 8 is described with satisfactory accuracy by the classical adsorption isotherms of Freundlich, Langmuir, and Dubinin-Radushkevich. The studies performed with the use of X-ray powder diffraction and thermal analyses, IR, Raman, and Mössbauer spectroscopy have shown that the uptake of nickel ions by iron (III) hydroxide precipitate is due to simple physical adsorption and is not accompanied by the formation of mixed iron and nickel compounds. No alloying of the formed iron (III) hydroxide precipitate with nickel ions takes place either. The formed iron (III) hydroxide precipitate is a two-line ferrihydrite having the gross formula Fe2 O3 × 3H2 O. Its sorption capacity for nickel ions is almost an order of magnitude higher than that of some mineral and carbon sorbents, and at pH7 and 8, it is 60.5 and 141.9mg/g, respectively. PRACTITIONER POINTS: Coagulant FeCl3 cleans contaminated solutions from Ni(II) ions. Iron (III) hydroxide precipitated at pH 7 and 8 is a two-line ferrihydrite Fe2 O3 × 3H2 O. Removing of Ni(II) ions is described by classical adsorption isotherms. The most complete removal of Ni(II) ions occurs at pH = 8.

Complexes of Sodium Pectate with Nickel for Hydrogen Oxidation and Oxygen Reduction in Proton-Exchange Membrane Fuel Cells.

A number of nickel complexes of sodium pectate with varied Ni2+ content have been synthesized and characterized. The presence of the proton conductivity, the possibility of the formation of a dense spatial network of transition metals in these coordination biopolymers, and the immobilization of transition ions in the catalytic sites of this class of compounds make them promising for proton-exchange membrane fuel cells. It has been established that the catalytic system composed of a coordination biopolymer with 20% substitution of sodium ions for divalent nickel ions, Ni (20%)-NaPG, is the leading catalyst in the series of 5, 15, 20, 25, 35% substituted pectates. Among the possible reasons for the improvement in performance the larger specific surface area of this sample compared to the other studied materials and the narrowest distribution of the vertical size of metal arrays were registered. The highest activity during CV and proximity to four-electron transfer during the catalytic cycle have also been observed for this compound.

Synthesis of copper nanosquare and nanorectangular using novel precursor (substituted benzoic acid complexes)

The ligand 3,4,5-trimethoxybenzoic acid was used to prepare a series of its complexes with divalent manganese, cobalt, nickel and copper ions in a molar ratio of 2 ligand: 1 metal to give the complexes of formula [M(TMA)2].xH2O, M = Mn, Co; x = 0 or M = Ni, Cu; x = 2. The prepared complexes were characterized using FTIR, UV–Vis, CHN, molar conductivity, thermal analysis and magnetic susceptibility. The measurements proved that the TMA anion has the ability to bind with the studied metals by the behaviour of the bidentate chelate through the oxygen atoms of the carboxylic group. The complex [Cu(TMA)2] was used as a starting material to prepare copper nanoparticles using ascorbic acid in the presence of tween as a dispersant, which was characterized by X-ray diffraction and TEM technique. The TEM measurement proves that the copper was prepared with nanoscale with rectangular (53*70 nm) and square (30–32*30–32 nm) nanoparticles and the X-ray diffraction measurement proved that the formed copper was of high purity.

Surface magnetization of hydrolyzed Luffa Cylindrica biowaste with cobalt ferrite nanoparticles for facile Ni2+ removal from wastewater

A novel magnetic adsorbent based on hydrolyzed Luffa Cylindrica (HLC) was synthesized through the chemical co-precipitation technique, and its potential was evaluated in the adsorptive elimination of divalent nickel ions from water medium. Morphological assessment and properties of the adsorbent were performed using FTIR, SEM, EDX, XRD, BET, and TEM techniques. The effect of pH, temperature, time and nickel concentration on the removal efficiency was studied, and pH = 6, room temperature (25 °C), contact time of 60 min, and Ni2+ ion concentration of 10 mg.L−1 were introduced as the optimal values. At optimal conditions, the removal efficiency of Ni2+ ions using HLC and HLC/CoFe2O4 magnetic composite was calculated as 96.38 and 99.13%, respectively. The adsorption process kinetic followed a pseudo-first-order model. Langmuir isotherm was suitable for modelling the experimental data of the Ni2+ adsorption. The maximum elimination capacity of HLC and HLC/CoFe2O4 samples was calculated as 42.75 and 44.42 mg g−1, respectively. Furthermore, thermodynamic investigations proved the spontaneous and exothermic nature of the process. The adsorption efficiency was decreased with increasing the content of Ca2+ and Na + cations in aqueous media. During reusability of the synthesized adsorbents, it was found that after 8 cycles, no significant decrease has occurred in the adsorption efficiency. In addition, real wastewater treatment results proved that HLC/CoFe2O4 magnetic composite has an excellent performance in removal of heavy metals pollutant from shipbuilding effluent.

Porphyrin Coordination Polymer with Dual Photocatalytic Sites for Efficient Carbon Dioxide Reduction.

The resurgence of visible light photocatalysis for carbon dioxide reduction reaction (CO2RR) has resulted in the generation of various homogeneous and heterogeneous paradigms. Herein, a new system has been established by incorporating dual catalytic sites into porous coordination polymer toward the photocatalysis of CO2RR. A functional ligand, 5,10,15,20-tetrakis[4'-(terpyridinyl)phenyl]porphyrin (TTPP), has been used to assemble discrete divalent nickel ions into the coordination polymer (TTPP-Ni) through metal bis(terpyridine) nodes. Both the porphyrin and terpyridine moieties prefer to bind with nickel ions, giving rise to TTPP-Ni with dual active catalytic sites. By controlling different molar ratios of ligand and metal and the reaction temperature, four samples including TTPP-Ni-n (n = 1, 2, 3, and 4) with different molar ratios of nickel porphyrin and nickel bis(terpyridine) subunits have been fabricated. The predesigned two-dimensional chemical structures of TTPP-Ni samples have been fully characterized using powder X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and IR and UV-vis spectroscopies. The photocatalytic activities of these coordination polymers have been screened using [Ru(bpy)3]Cl2·6H2O as a photosensitizer together with triisopropanolamine as the sacrificial electron donor in CH3CN and H2O. Among these photocatalysts, TTPP-Ni-3 and TTPP-Ni-4 with almost saturated metal sites are able to display extraordinary photocatalytic performance including a CO generation rate of ca. 3900 μmol g-1 h-1 and 98% selectivity. The mechanism associated with dual active sites has been rationalized on the basis of theoretical simulations.

Controllable synthesis and magnetic properties of NiAl0.8Fe1.2O4 electrospun nanofibres

A convenient strategy for fabricating spinel ferrite NiAl0.8Fe1.2O4 (NAFO) nanofibres with a controllable draw ratio by an electrospinning technique was investigated. The surface topography and draw ratio of the NAFO nanofibres can be tuned by adjusting the molarity and polymer concentration of the precursors, calcination temperature and spinning voltage. Investigation of the magnetic performances showed that the saturation magnetization of NAFO nanofibres increased with increasing calcination temperature. This was interpreted by considering the cationic redistribution in the oxygen octahedral and oxygen tetrahedral sites of the mixed spinel ferrite as confirmed by X-ray diffraction, Raman spectra and X-ray photoelectron spectroscopy analysis. As the calcination temperature increased, the ferric ions showed a tendency to shift to the oxygen octahedral sites, while the divalent nickel ions showed a tendency to shift to the oxygen tetrahedral sites, which then strengthened the saturation magnetization of the NAFO nanofibres. The controllable synthesis strategy and the interpretation of the magnetic properties will shed some light on the application of one-dimensional NAFO nanofibres in spintronic and nanomagnetoelectric devices.

MAGNETIC AND ELECTRONIC SPECTRAL STUDIES OF FOUR, FIVE AND SIX COORDINATED COMPLEXES OF SUBSTITUTED HYDRAZIDE AND HYDRAZONES WITH DIVALENT NICKEL AND COBALT METAL IONS

Metal complexes of divalent Nickel and Cobalt metal ions have been synthesized with picolinic acid hydrazide (PH) , ortho -hydroxy acetophenone picolinoyl hydrazone ( APH) and ortho-hydroxy acetophenone iso-nicotinoyl hydrazone (AIH) ligands and were isolated at both high pH and low pH. These complexes were characterized by elemental analyses and also by electronic spectral studies and magnetic measurements. Ligands PH and AIH act as tridentate, while APH is tetradentate. All form two types of complexes, depending upon pH of the reaction mixture. At high pH complexes formed are monomeric while at high pH complexes were found to be dimeric. Dimerisation is initiated by enolic oxygen which acts like a bridging ligand between two metal ions.

Electrodeposition of Nickel/Graphene Oxide Particle Composite Coatings: Effect of Surfactants on Graphene Oxide Dispersion and Coating Performance

The dispersibility of graphene oxide particles (GOs) in nickel electrolytes is critical for its uniform incorporation in the nickel matrix during the electrodeposition process. In this study, we study the fundamental interaction of surfactants and nickel ionic strength for uniform and stable incorporation of GOs in nickel electrolytes and their effect on coating performance. The results indicate that the non-ionic surfactant Polyethylene glycol (PEG) has the optimal dispersibility of GOs in nickel electrolyte, followed by the cationic surfactant Cetyltrimethylammonium bromide (CTAB) and the anionic surfactant Sodium dodecyl sulfate (SDS). It is also noted that the increasing nickel ionic strength would deteriorate the stability of GOs, attributing to the generation of cross-linking of high strength divalent nickel ions with dispersed graphene oxide. The electrodeposited coatings show that more incorporation of graphene oxide in the coating is achieved when the PEG surfactant is used, which leads to an increased hardness by 146% and a decreased friction coefficient by 72.7% under low nickel sulfamate concentration (200 g l−1), compared to pure nickel coating. Eventually, the study shows that higher nickel ionic strength would deteriorate the performance of the coatings, while the selection of proper surfactant can compensate for it.

Copper oxide nanoparticles for the removal of divalent nickel ions from aqueous solution

This study focused on the synthesis of copper oxide (CuO) nanoparticles by chemical precipitation method for the uptake of divalent nickel ions from aqueous media. The adsorption capacity was 15.4 mg/g under optimum conditions. The kinetic models were applied to find out the mechanism for the removal of nickel ions. The study indicated that the optimum conditions for nickel sequestration were pH = 7.0, initial concentration = 100 mg/L, nanoparticle dose = 0.2 g/L, contact time = 90 min, temperature = 26 ± 1 °C and rpm = 180. These results could be useful for the sequestration of Ni(II) ions from wastewater.

PH dependent chelation study of Zn(II) and Ni(II) by a series of hexapeptides using electrospray ionization – Ion mobility – Mass spectrometry

Presented here are the results of a study characterizing the selective metal chelating performance of the alternative metal binding (amb) peptide: acetyl-His1-Cys2-Gly3-Pro4-His5-Cys6-OH, and eight ambs with systematic modifications to His, Cys, and carboxyl C-terminus metal chelating sites. The results show that from the divalent metal ions of zinc, nickel, cobalt, magnesium and calcium, the ambs most extensively formed complexes with zinc and nickel. The ambs, which retained both Cys2 and Cys6 in their primary structure, exhibited the greatest formation of zinc complexes. The replacement of His1 and His5 residues with two additional Cys with the amidation of the C-terminus also increased the zinc chelation at pH 7.0. Density functional theory indicated that these modifications might be disrupting the hydrogen bonding between the His-Cys and carboxylate terminus making the 4Cys more available for chelation. Nickel chelation was generally lower than zinc because of competition from the Cys to form disulfide bonds in the presence of nickel. The two ambs that formed the highest number of nickel complexes both included the amidated C-termini and either 4Cys or 2Cys-2His. Comparison with recent published results of six heptapeptide ambs, which have the same primary structures, but with the inclusion of Tyr5 before the final two residues, indicates the inclusion of the Tyr5 residue increases the zinc chelation at pH 7.0 from 25%, of total observed species, to 70%. These types of studies may pave the way to discoveries of new therapeutics suitable as enzyme inhibitors or chelators for diseases associated with metal homeostasis misbalances, or as new peptide tags for recombinant protein purification.

Effective Adsorption of Hexavalent Chromium and Divalent Nickel Ions from Water through Polyaniline, Iron Oxide, and Their Composites

Water pollution caused by industrial wastes containing heavy metals and dyes is a major environmental problem. This study reports on the synthesis, characterization, and utilizations of Polyaniline (PANI) and its composites with Fe3O4 for the removal of hexavalent chromium Cr(VI) and divalent nickel Ni(II) ions from water. The adsorption data were fitted in Freudlich, Langmuir, Tempkin, Dubbanin–Ruddishkawich (D–R), and Elovich adsorption isotherms. The Freundlich isotherm fits more closely to the adsorption data with R2 values of 0.9472, 0.9890, and 0.9684 for adsorption of Cr(VI) on Fe3O4, PANI, and PANI/Fe3O4 composites, respectively, while for adsorption of Ni(II) these values were 0.9366, 0.9232, and 0.9307 respectively. The effects of solution pH, initial concentration, contact time, ionic strength, and adsorbent dosage on adsorption behavior were investigated. The adsorption ability of composites was compared with pristine PANI and Fe3O4 particles. Activation energy and other thermodynamic properties such as changes in enthalpy, entropy, and Gibbs free energy indicated spontaneous and exothermic adsorption.

Novel series of nanosized mono- and homobi-nuclear metal complexes of sulfathiazole azo dye ligand: Synthesis, characterization, DNA-binding affinity, and anticancer activity

Novel five nanosized mono- and homobi-nuclear complexes of 4-(2,4-dihydroxy-5-formylphen-1-ylazo)-N-thiazol-2-yl-benzenesulfonamide (H2L) ligand were synthesized for developing new anticancer agents. H2L was prepared by coupling the diazonium salt of 2-(p-aminobenzenesulfonamido)thiazole with 2,4-dihydroxybenzaldehyde in order to integrate the bio-effectiveness of both azo group and sulfonamide part in the synthesized metal chelates which strongly increase their bio-activities. H2L and synthesized Cu, Co, Ni, Mn and Zn complexes were characterized applying different analytical and spectral methods. The obtained results revealed that H2L coordinated with divalent metal ions of copper, cobalt and nickel in a monobasic bidentate mode through the azo group nitrogen, and deprotonated phenolic oxygen whereas H2L coordinates with Mn(II), and Zn(II) in dibasic tetradentate mode via the azo group nitrogen, deprotonated phenolic oxygen, sulfonamide oxygen, and N-atom of thiazole ring. All metal complexes had a tetrahedral geometry around the metal centers. XRD patterns denoted the ligand crystalline and the complexes amorphous natures. TEM images proved the nanosized range of all complex's particles. UV–Vis spectra and viscosity techniques revealed that H2L and complexes exhibited groove binding mode interactions with DNA. Anticancer efficiency of the ligand and complexes were examined against breast carcinoma cells (MCF-7) and human liver carcinoma cells (HepG-2). Co(II) and Zn(II) complexes displayed the greatest anticancer activity and are very promising candidates for future applications in cancer therapy.

Ab initio analysis of the optical spectra and EPR parameters of Ni2+ ions in CaF2 and CdF2 crystals

Crystals with fluorite type structure doped with transition metals (TM) in different oxidation states provide the possibility of investigating optical spectra, magnetic properties and ligand field (LF) parameters of TM in cubic eightfold coordination. If the doped ion in the host crystal matrix has a degenerate ground state then, due to the strong T⊗τ Jahn-Teller (JT) effect, the cubic coordination geometry of the impurity ion will be distorted to octahedral, with the change in its properties. In this paper we present the results of the ab initio investigation of absorption optical spectra, JT stabilization energy in the ground state, spin-Hamiltonian and ligand field parameters of divalent nickel ion doped in cubic CaF2 and CdF2 crystals. The analysis of new cluster [NiF6]4- with trigonal symmetry (D3d) at the Ni2+site was made based on the ab initio multireference methods (MR). All calculations are applied to the [NiF6]4- cluster embedded in an extended point charge field of host matrix ions built according to the Gellé-Lepetit procedure. After density functional theory (DFT) optimization of the doped crystals, the ab initio energy calculation of the electronic states and corresponding wave functions of Ni2+ ions is performed from the complete active space self-consistent field (CASSCF). The improved energy states obtained by using different approaches such as N-electron valence second order perturbation theory (NEVPT2), second order dynamic correlation dressed complete active space (DCD-CAS2), difference dedicate configuration interaction with three degrees of freedom (MRDDCI3) and spectroscopy-oriented configuration interactions (SORCI), were analyzed. In addition, the ab initio ligand field theory (AILFT) procedure allows extracting all LF parameters and spin-orbit coupling constant. The obtained results are discussed and the comparison with the available in the literature corresponding experimental values literature yields a reasonably agreement between theory and experiment, which justifies this new route of investigation.The structural mechanism around Ni2+ center through JT effect, combined with the above mentioned methodology, allows for more consistent and reliable calculations of optical spectra and spin-Hamiltonian parameters of any impurity ions doped in eightfold cubic coordination.