Heteronuclear Complexes Research Articles

Heteronuclear Glycinate Complexes of Fe(II), Fe(III) and Co(II), Their Model Parameters

The system Fe(II)–Fe(III)–Co(II)–Gly–H2O was studied by the Clark–Nikolsky oxidation potential method at a temperature of 298.15 K, ionic strength of the solution [Na(H)CIO4] I = 1.0 mol/l. The formation of mononuclear and heteronuclear compounds of various compositions in the system was found: [FeHL(H2O)5]3+, [Fe(HL)2(H2O)4]3+, [Fe(HL)(OH)(H2O)4]2+, [СoL(H2O)5]+, [FeIIIСoIIL(H2O)11]4+, [FeIIIСoII(L)2(H2O)10]3+, [FeL(H2O)5]+, [Fe(HL)2(H2O)4]2+, [Fe(HL)(OH)(H2O)4]+ and [Fe(HL)(OH)2(H2O)3]0. The stability and model parameters of coordination compounds were calculated by the Yusupov oxidation function iteration method, and their coordination compound distribution diagrams were constructed. It was found that the heteronuclear complex [FeIIIСoIIL(H2O)11]4+ is the most stable, with an accumulation degree of 99.50%, and exists up to pH = 9.5.

Study of Complexation Patterns in the System Ni2+, MoO42–, P2O74–, Cit3–for the Development of Poly-Ligand Electrolytes (Study of complexation patterns)

The complexation behavior in systems containing Ni2+, MoO42−, P2O74−, Cit3− - ions have been thoroughly investigated. The study determined the composition and instability constants of both mono- and biligand complex compounds at a constant ionic strength of the solution (Ic=1). By analyzing the concentration ratios of the complexing agent and ligands, the composition of mono- and polyligand complexes was elucidated. The complexation study utilized the potentiometric method, which is based on the functional dependence of the potential of the indicator electrode on the concentration of the complexing agent ions. The results enabled the calculation of the ionic composition of aqueous solutions of nickel complexes with citrate and diphosphate ions, depending on their concentrations. A proposed scheme for the formation of heteronuclear nickel-molybdenum complexes takes into account the sequence of component introduction into the electrolyte to form complexes of a specific composition. These findings were applied to develop electrolyte compositions for coating with alloys based on iron subgroup metals with molybdenum. These alloys exhibit several valuable properties, including corrosion resistance, electrocatalytic activity in hydrogen production, and enhanced operational characteristics.

Heteronuclear Fe-Mn Cyclopentadienyl Complexes Supported on Boehmite. Thermochemistry and Thermodynamics of their Decomposition

Boehmite samples with compounds of the composition (C5H5)2FeMnX2(μ-CO)n, where X=Cl, Br and n=1.2, precipitated at room temperature from tetrahydrofuran solutions and then heated in an air flow up to 873 K were obtained and characterized using X-ray diffractometry, infrared Fourier spectroscopy, electron magnetic resonance and temperature-programmed desorption methods. It was shown that the thermal decomposition of these compounds applied to the boehmite samples in the range from room temperature to 873 K occurs stepwise and consists of at least two stages. The first stage of thermal decomposition occurs in the range of 453–753 K, and the second – in the range of 813–843 K. The XRD data show that when calcining at 873 K the boehmite samples with the applied compounds of the above composition and containing these compounds less than 10 wt.%, the diffraction patterns show only reflections characteristic of poorly crystallized aluminum oxide. However, the electron paramagnetic resonance (EPR) spectra of these samples clearly show intense signals characteristic of superpara/ferromagnetic particles of iron and manganese oxides, as well as EPR signals from isolated Fe3+ substituting Al3+ ions in the aluminum oxide structure. EPR spectra most of the iron and manganese is stabilized on the surface of poorly crystallized aluminum oxide in the form of nanostructured iron and manganese oxides.

Study of Chemical Reactions in Molten Salts By Electrochemical Transient Techniques

Processes of electrodeposition and electrochemical synthesis in many cases are accompanied by chemical reactions. In the present work, the following chemical reactions: comproportionation, disproportionation, displacement, cluster formation, heteronuclear complex formation, polymerization, competitive complex formation, and acidic-basic have been studied by electrochemical transient techniques. The effect of chemical reactions on the composition of electrolysis products is discussed and methods of suppressing the reactions complicating the electrolysis processes are suggested. The results of the synthesis of functional materials using chemical reactions are presented.

Upconversion Luminescence in a Photostable Ion‐Paired Yb−Eu Heteronuclear Complex

AbstractLanthanide‐based upconversion molecular complexes have potential application in diverse fields and attracted considerable research interest in recent years. However, the similar coordination reactivity of lanthanide ions has constrained the designability of target molecule with well‐defined structure, and many attempts obtained statistical mixtures. Herein, an ion‐paired Yb−Eu heteronuclear complex [Eu(TpPy)2][Yb(ND)4] (TpPy=tris[3‐(2‐pyridyl)pyrazolyl]hydroborate, ND=3‐cyano‐2‐methyl‐1,5‐naphthyridin‐4‐olate) was designed and synthesized. Thanks to the radius difference between Eu3+ (1.07 Å) and Yb3+ (0.98 Å) ions, the hexadentate TpPy ligand was selected to coordinate with Eu3+ and the Yb3+ with a smaller radius was chelated by bidentate ND ligand. As a result, the sites of Eu3+ and Yb3+ in the complex can be clarified by high‐resolution mass spectrometry and single‐crystal structure analysis. Upon the excitation of Yb3+ at 980 nm, the upconversion emission of Eu3+ was realized through a cooperative sensitization process. Furthermore, [Eu(TpPy)2][Yb(ND)4] demonstrated excellent photostability during continuous high‐power density 980 nm laser irradiation, with a LT95 (the time to 95 % of the initial emission intensity) of 420 minutes. This work provides the first example of a pure ion‐paired Yb−Eu heteronuclear complex upconversion system and may bring insights into rational design of lanthanide‐based upconversion molecular complexes.

Upconversion Luminescence in a Photostable Ion-Paired Yb-Eu Heteronuclear Complex.

Lanthanide-based upconversion molecular complexes have potential application in diverse fields and attracted considerable research interest in recent years. However, the similar coordination reactivity of lanthanide ions has constrained the designability of target molecule with well-defined structure, and many attempts obtained statistical mixtures. Herein, an ion-paired Yb-Eu heteronuclear complex [Eu(TpPy)2][Yb(ND)4] (TpPy=tris[3-(2-pyridyl)pyrazolyl]hydroborate, ND=3-cyano-2-methyl-1,5-naphthyridin-4-olate) was designed and synthesized. Thanks to the radius difference between Eu3+ (1.07 Å) and Yb3+ (0.98 Å) ions, the hexadentate TpPy ligand was selected to coordinate with Eu3+ and the Yb3+ with a smaller radius was chelated by bidentate ND ligand. As a result, the sites of Eu3+ and Yb3+ in the complex can be clarified by high-resolution mass spectrometry and single-crystal structure analysis. Upon the excitation of Yb3+ at 980 nm, the upconversion emission of Eu3+ was realized through a cooperative sensitization process. Furthermore, [Eu(TpPy)2][Yb(ND)4] demonstrated excellent photostability during continuous high-power density 980 nm laser irradiation, with a LT95 (the time to 95 % of the initial emission intensity) of 420 minutes. This work provides the first example of a pure ion-paired Yb-Eu heteronuclear complex upconversion system and may bring insights into rational design of lanthanide-based upconversion molecular complexes.

Understanding Stabilization Factors in Heterodinuclear Ln-Al Complexes from DFT Simulations on Thermochemistry Data: A Counterintuitive Conclusion.

This study validates a computational protocol to predict the stability of heterodinuclear complexes by varying ligands on both moieties and analyzing the reaction Gibbs free energy (ΔGr) values. To this purpose, a series of Eu-Al complexes with the general formula [Eu(LEu)3Al(LAl)3], where LEu is the ligand of europium and LAl is an oxygen donor ligand of aluminum, is used. The nature of the bridging bonds and thermochemical characteristics (ΔGr, enthalpy, and entropy) of the complexes were evaluated via DFT calculations. We demonstrated that both entropic and enthalpic effects play a relevant role in the stability. The analysis of the series allows us to identify three ΔGr ranges where heterodinuclear complexes are (i) stable and easy to characterize, (ii) fragile and difficult to characterize, and (iii) not observed (unreacted precursors are recovered). To rationalize the trend of the stability and correlate it with the chemical nature of the ligands, we investigated the condensed Fukui function on the Al fragment. Results suggest that to obtain stable heteronuclear complexes, it is necessary to consider ligands with small condensed Fukui function values. This corresponds to a less nucleophilic oxygen site, yet counterintuitively, it allows the ligand to delocalize the received electronic charge and stabilize the complex.

Heteronuclear Complexes with Promising Anticancer Activity against Colon Cancer.

This study investigates the activity of novel gold(I) and copper(I)/zinc(II) heteronuclear complexes against colon cancer. The synthesised heteronuclear Au(I)-Cu(I) and Au(I)-Zn(II) complexes were characterised and evaluated for their anticancer activity using human colon cancer cell lines (Caco-2). The complexes exhibited potent cytotoxicity, with IC50 values in the low micromolar range, and effectively induced apoptosis in cancer cells. In the case of complex [Cu{Au(Spy)(PTA)}2]PF6 (2), its cytotoxicity is ×10 higher than its mononuclear precursor, while showing low cytotoxicity towards differentiated healthy cells. Mechanistic studies revealed that complex 2 inhibits the activity of thioredoxin reductase, a key enzyme involved in redox regulation, leading to an increase in reactive oxygen species (ROS) levels and oxidative stress, in addition to an alteration in DNA's tertiary structure. Furthermore, the complexes demonstrated a strong binding affinity to bovine serum albumin (BSA), suggesting the potential for effective drug delivery and bioavailability. Collectively, these findings highlight the potential of the investigated heteronuclear Au(I)-Cu(I) and Au(I)-Zn(II) complexes as promising anticancer agents, particularly against colon cancer, through their ability to disrupt redox homeostasis and induce oxidative stress-mediated cell death.

Synthesis, structural diversity, supramolecular architecture, and catalytic reactions of mononuclear and heteronuclear benzamide cobalt complexes

Two NNN-type benzamide derivative ligands {N,N'-(2,2′-azenidiyl-bis(2,1-phenylene))dicyclohexanecarboxamide (H3LcyHex) and N,N'-(2,2′-azenidiyl-bis(2,1-phenylene))dicyclobutanecarboxamide (H3LcyBu)} that incorporate N-amidate donors have been synthesized and characterized by 1H NMR, 13C NMR, and FT-IR techniques. Subsequently, heterometallic trinuclear cobalt-potassium complexes, [K2(DMF)6Co(HL)2] (KCyBu and KCyHex) and mononuclear cobalt complexes with complementary tetraethylammonium ions, [Et4N]2[Co(HL)2] (ECyBu and ECyHex), both incorporating these ligands, have been synthesized. Suitable crystals for single-crystal X-ray diffraction of H3LcyHex and KCyBu have been characterized using single-crystal X-ray diffraction analysis. Intermolecular interactions play a major role in the formation of the supramolecular architecture in the crystal lattice of compounds. The supramolecular structures in H3LcyHex are formed through intermolecular CH⋅⋅⋅O, CH⋅⋅⋅π, CH⋅⋅⋅O/N, and CH⋅⋅⋅N interactions, and those in KCyBu are generated by CH⋅⋅⋅π and CH⋅⋅⋅O intermolecular interactions. The amphoteric properties exhibited by new cobalt-oxygen species produced through the reaction of cobalt complexes with molecular oxygen were examined by their electrophilic reactivity in the conversion of triphenylphosphine (PPh3) to triphenylphosphoxide (OPPh3) and their nucleophilic reactivities in the deformylation reaction of 2-phenylpropionaldehyde (2-PPA) to acetophenone (catalyst/substrate ratio, 1:100). In the catalytic activity results, it was observed that the cobalt-oxygen complexes have an amphoteric feature due to their good reactivity in both reactions.

Cd-Ln (Ln = Pr, Sm, Yb and Nd) heteronuclear complexes based on the linear chain ether Schiff base: Structural regulation and fluorescence properties

Four structurally different Cd-Ln heteronuclear complexes based on the linear chain ether Schiff base ligand (bis(3-methoxysalicylidene)-3-oxapentane-1,5-diamine (H2L) and the co-ligands 4,4′-bipyridine (bipy) or isonicotinate (IN), with composition [PrCd2L2(CH3COO)2](NO3)·CH2Cl2 (1), {[SmCdL(bipy)(NO3)3]·CH2Cl2·CH3CH2OH}n (2), [YbCdL(IN)(NO3)(CH3COO)]n (3) and {[Nd2Cd2L2(IN)2(NO3)2(CH3OH)2(CH3COO)](NO3)}n (4), have been synthesized by interfacial diffusion methods. Structural regulation is achieved by changes in the co-ligands or Ln(III) ions of different radii: Single crystal X-ray analysis determined that 1 is a trinuclear cluster with the Pr(III) ion as a joint bridging of two CdL coordination units; 2 and 3 are both infinite one-dimensional zigzag coordination polymers consisting of CdLnL secondary units through coordination bridging bipy or IN; 4 is a two-dimensional graphene laminate structure formed by two types of CdNdL secondary units bridged by both IN and acetate simultaneously. In the solid state, the complexes 1–4 all exhibit fluorescence peaks based on H2L with blue shift and enhancement. The order of fluorescence peaks intensity of the complexes in N,N-dimethylformamide (DMF) solution is consistent with that in the solid state. Moreover, the corresponding characteristic emissions of Sm(III) ion in complex 2 can be observed in the fluorescence spectra in either solid state and DMF solution, indicating that [CdL] unit is suitable for the sensitization of Sm(III) ion.

Observation of the Transition from Triple Bonds to Single Bonds between Ru-Ge Bonding in RuGeO(CO)n- (n = 3-5).

This work reports the observation and characterization of heterobinuclear transition-metal main-group metal oxide carbonyl complex anions, RuGeO(CO)n- (n = 3-5), by combining mass-selected photoelectron velocity map imaging spectroscopy and quantum chemistry calculations. The experimentally determined vertical electron detachment energy of RuGeO(CO)3- surpasses those of RuGeO(CO)4- and RuGeO(CO)5-, which is attributed to distinctive bonding features. RuGeO(CO)3- manifests one covalent σ and two Ru-to-Ge dative π bonds, contrasting with the sole covalent σ bond present in RuGeO(CO)4- and RuGeO(CO)5-. Unpaired spin density distribution analysis reveals a 17-electron configuration at the Ru center in RuGeO(CO)3- and an 18-electron configuration in RuGeO(CO)4- and RuGeO(CO)5-. This work closes a gap in the quantitative physicochemical characterization of heteronuclear oxide carbonyl complexes, enhancing our insights into catalytic processes of CO/GeO on the metal surface at the molecular level.

Elucidating the crystal structures of heteronuclear salen complexes CuL-CdX2 with experimental and computational methods

Two novel heteronuclear salen-type complexes, CuL1-CdCl2 and CuL2-CdI2, have been successfully synthesized and characterized. The characterization processes utilized single-crystal X-ray diffraction, elemental, and FT-IR analysis, revealing the structural properties of the complexes. In both complexes, the Cu(II) ion exhibited an approximate square planar geometry (CuN2O2), where the deprotonated phenoxide-type ligand L2− coordinated to form N2O2. Conversely, For CuL1-CdCl2, the Cd(II) ion displayed a trigonal prismatic geometry, surrounded by two chlorine atoms and four oxygen atoms. Intermolecular and intramolecular interactions within the complex were facilitated by CH···Cl, CH···N, and CH···O hydrogen bondings. For CuL2-CdCl2, the Cd(II) ion displayed a trigonal prismatic geometry, surrounded by two iodine atoms and four oxygen atoms. Intermolecular interactions within the complex were facilitated by weak CH···I hydrogen bonding, while the overall stability of the framework was ensured through weak π···π stacking interactions. According to the Hirshfeld surface analysis results, the H···H contacts constitute a large part of the total surface area for both complexes; this highlights the importance of hydrogen bond interactions in stabilizing the crystal arrangement. The theoretical analysis of the complexes was executed by using Becke's three-parameter hybrid functional for the exchange component and the Lee-Yang-Parr (LYP) correlation function with the LanL2DZ basis set to achieve the optimized geometrical parameters. The results showed that experimental and theoretical calculations were in agreement.

Heteronuclear Complexes of Hg(II) and Zn(II) with Sodium Monensinate as a Ligand.

The commercial veterinary antibiotic sodium monensinate (MonNa) binds mercury(II) or zinc(II) cations as thiocyanate [Hg(MonNa)2(SCN)2] (1) or isothiocyanate [Zn(MonNa)2(NCS)2] (2) neutral coordination compounds. The structure and physicochemical properties of 1 and 2 were evaluated by the methods of single crystal and/or powder X-ray diffraction, infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopies, and electrospray-mass spectrometry. The primary cores of the two complexes comprise HgS2O2 (1) and ZnN2O2 (2) coordination motifs, respectively, due to the ambidentate binding modes of the SCN-ligands. The directly bound oxygen atoms originate from the carboxylate function of the parent antibiotic. Sodium cations remain in the hydrophilic cavity of monensin and cannot be replaced by the competing divalent metal ions. Zinc(II) binding does not influence the monensin efficacy in the case of Bacillus cereus and Staphylococcus aureus whereas the antimicrobial assay reveals the potential of complex 2 as a therapeutic candidate for the treatment of infections caused by Bacillus subtilis, Kocuria rhizophila, and Staphylococcus saprophyticus.

Single molecule magnet behaviour of CoIIILnIII (Ln = TbIII, GdIII) compounds with compartmental Schiff base ligand and sulfonate co-ligands

In this research, our team synthesized and characterized two heteronuclear 3d-4f complexes, [CoIIICl(μ-valen)(μ-4-HBS)LnIII(NO3)(H2O)(4-HBS)], with Ln representing Tb (1) and Gd (2). Achievement of this was through the utilization of a compartmental Schiff base ligand H2valen, alongside secondary co-ligands Na(4-HBS) [H2valen=6,6′-((1E,1′E)-(ethane-1,2-diylbis(azaneylylidene))bis(methaneylylidene))bis(2-methoxyphenol); Na(4-HBS)=sodium 4-hydroxybenzenesulfonate]. X-ray crystallography revealed that both complexes feature a similar [Co(III)-Ln(III)] core, connected by the phenoxo-O atoms from the compartmental Schiff base ligand and the sulfonate-O atoms from the co-ligand. In this context, Co(III) displays a distorted octahedral geometry within a CoN2O3Cl coordination sphere, while Ln(III) exhibits a muffin (MFF)-like distorted geometry in a LnO9 coordination sphere. Magnetic analysis shows that the two complexes display unique magnetic properties. Complex 1 exhibits pronounced SMM behavior, with a notable energy barrier of 14.8 K for magnetization reversal. However, complex 2 presents a minor energy barrier of 4.8 K. Additionally, complexes 1 and 2 represent uncommon examples of dinuclear Co(III)-Ln(III) SMMs.

Heteronuclear complexes [MDyM](M=Cu; Zn; Ni) constructed by Schiff base ligands with different amine backbone exhibiting significant single-molecule magnets

Series of 3d-4f heterotrinuclear complexes [MDyM] (M=Zn, Cu, Ni) with formula [Cu2(L1)2DyCl2(H2O)]·Cl·MeCN (1), [Cu2(L2)2DyCl2]n (2), [Cu2(L3)2DyCl2(MeOH)2]·Cl·(MeOH)3 (3), [Zn2(L1)2DyCl2(H2O)]·Cl·MeCN (4) and [Ni2(L1)2DyCl3]·(CH2Cl2)2 (5) were constructed by three hexadentate compartment Schiff bases (L1 = N,N'-bis(3-methoxysalicylidene)-2,2-dimethylpropane-1,3-diamine; L2 = N,N'-bis(3-methoxysalicylidene)-1,3-propanediamine; L3 = N,N'-bis(2‑hydroxy-3-methoxybenzylidene)-1,2-phenylenediamine). Different electronic and steric effects of amine backbone lead to linear-type M-Dy-M, one-dimensional (1D) chain and interlayer-type structures of complexes 1–5, respectively. Among these, complexes 1, 4 and 5 were constructed as the M-Dy-M linear-type coordination configuration containing diamagnetic zinc(II) ions and paramagnetic copper(II) ions or nickel(II) ions respectively. Molecular magnetic studies reveal that complexes 1, 4, 5 and chain complex 2 exhibited significant single-molecule magnets (SMMs) behavior and the notable hysteresis loops at maximum temperature of 3.5 K, 3 K, 7.5 K, and 4 K are observed, which are comparable among the outstanding heteronuclear (d/f) SMMs constructed by Schiff base ligands.

Structural regulation and luminescence properties of Tb/Zn-Tb complexes based on aliphatic ether Schiff base

Three new Tb(III) complexes containing bis(N-3-methoxysalicylidene)-3- oxapentane-1,5-diamine (H2L) ligand, [Tb(H2L)(NO3)3] (1), [ZnTbL(NO3)2(OAc)(MeOH)] (2), [Zn4Tb2L4(TP)2](NO3)2·DMF (3) (DMF = N,N-dimethylformamide, TP = terephthalate) have been synthesized by ether diffusion and structurally characterized. Complex 1 is a mononuclear, whereas complex 2 forms a heterodinuclear Zn-Tb cluster when introducing zinc ion into the reaction system of Complex 1. Complex 3 is a Zn-Tb heterohexanuclear cluster by adding terephthalic acid into the reaction system of complex 2. Solid-state luminescence studies show that the luminescence peaks of the ligand (π*→π) in the three complexes have undergone significant redshift and enhancement, which may be attributed to the coordination of ligand with metal ions. Moreover, the characteristic emission peak of terbium ions (5D4→7F5, at 545 nm for 2 and 546 nm for 3) appeared in heteronuclear complexes 2 and 3, while complex 1 did not. This indicates that the aliphatic ether Schiff base ligand cannot sensitize terbium ion to luminescence, while the zinc Schiff base complex [ZnL] unit can sensitize terbium ion to luminescence. Finally, the structures and luminescence properties of terbium complexes can be adjusted by the introduction of zinc(II) ion and co-ligand.

Embellished photosensitive Schottky barrier diode functionality of Ni(II)/Pb(II)-Salen complex with SCN− spacers: Insights from experimental and theoretical rationalization

This research article explores the synthesizing, structural characterizing, and photosensitive Schottky diode behaviour (PSBD) of one new hetero-nuclear Ni(II)/Pb(II)-Salen complex, [Ni2(L)Pb(μ-1,3-SCN)2(H2O)]2. The complex utilizes various analytical methods for characterization purposes, including single-crystal X-ray diffraction (SCXRD). Crystals have formed in the monoclinic space group P21/n within the compound. The complex asymmetric unit contains a deprotonated ligand (L2−), two Ni(II), one Pb(II), two SCN− ions, and Ni(II) metal coordination by H2O molecule. The crystallographic structure has octahedral and see-saw geometries around the Ni(II) and Pb(II) metal ions. The crystal structure reveals remarkable supramolecular interactions, with significant S⋯H contacts (13 %) evident from the Hirshfeld surface (HS) and 2-D fingerprint plots. The calculated optical band gap (3.14 eV) and UV–Visible measurement support the semiconductor behaviour. In addition, the compound shows electrical conductivity and photosensitivity (dark & light), suggesting potential applications in optoelectronic devices. The complex transports charge through space via a hopping process. The extensive experimental investigations indicate that exposure to visible light increases electrical conductivity compared to dark conditions, popularly known as PSBD behaviour. The complex conductivity function substantiates the DFT-based DOS, PDOS, and OPDOS plot analysis. Therefore, the heteronuclear complex has been successfully used in thin-film active devices despite technological challenges.

ЭЛЕКТРОХИМИЧЕСКОЕ ЛЕГИРОВАНИЕ ЦИНКОВЫХ ПОКРЫТИЙ ХРОМОМ И КОБАЛЬТОМ ИЗ ЭЛЕКТРОЛИТОВ, СОДЕРЖАЩИХ ГЕТЕРОЯДЕРНЫЕ КОМПЛЕКСЫ

The purpose of this work is the electrochemical alloying of zinc coatings with chromium and cobalt from glycine-containing electrolytes containing heteronuclear complexes. Currently, the development of electroplating is mainly aimed at creating environmentally safer industries. In solving these problems, low-waste technological processes with closed water circulation are introduced into industry, toxic substances are excluded from technological operations, and work is underway to reduce water consumption.An important area of work, in our opinion, is the production of alloyed coatings with effective performance characteristics. Obtaining such coatings allows the use of smaller thicknesses and longer service life, which helps to save material and energy resources, and in some cases solve environmental problems when replacing toxic metals, for example, cadmium. The processes of complexation in the zinc (II)-chromium (III)-cobalt (II) - glycine -water system were studied using NMR.The kinetics of the cathode process on zinc and steel electrodes has been studied by removing potentiodynamic polarization curves. It is suggested that the absence of characteristic current peaks on the polarization curves is due to the convergence of the electrode potentials of individual metal ions recovering from heteronuclear compounds, as well as the concomitant hydrogen release reaction.X-ray fluorescence analysis showed that in the studied current density range of 0.5-3.0 A/dm2, the content of alloying metals varies 0.01…2.00 for chromium and 0.1…3.6 for cobalt, respectively. The mass corrosion index for coatings alloyed with chromium and cobalt (cobalt content up to 1%) is 2 times less than for zinc coatings and is 0.05 g/m2·h.

ЭЛЕКТРОХИМИЧЕСКОЕ ЛЕГИРОВАНИЕ ЦИНКОВЫХ ПОКРЫТИЙ ХРОМОМ И НИКЕЛЕМ ИЗ ГЛИЦИНАТНЫХ РАСТВОРОВ

The purpose of this work is the electrochemical alloying of zinc coatings with chromium and nickel from electrolytes containing heteronuclear complexes. Zinc coatings are widely used to protect steel products from corrosion in the atmosphere of various climatic zones. To increase corrosion resistance, zinc coatings are chromated or phosphated. An effective way to increase the corrosion resistance of the coatings under study is their alloying with other metals. Obtaining such coatings makes it possible to reduce their thickness and increase their service life, solve environmental problems when replacing cadmium. The kinetics of the process on zinc and steel electrodes has been studied by removing cathode polarization curves. It is suggested that the absence of characteristic current peaks on the polarization curves is due to the convergence of the electrode potentials of individual metal ions recovering from heteronuclear compounds, as well as the concomitant discharge reaction of proton donors. X-ray fluorescence analysis has shown that in the studied range of current densities 1-5 A/dm2, the content of alloying metals in the coating reaches 1.4% for chromium and 9.8% for nickel. The obtained data on the elemental composition of zinc coatings indicate an abnormal co-deposition of zinc with nickel. Chromium in coatings is observed at higher current densities of 4-5 A/dm2.The data obtained in this work can be used in electroplating in the development of processes for alloying zinc coatings with chromium and nickel in order to replace cadmium coatings.

In-situ Salen-type ligand formation-driven of a heterometallic Cu(II)-Hg(II) complex: Synthetic update, crystallographic features, DFT calculations, and unveil antimicrobial profiles

This article vividly describes the synthesis and structural characterization of one 6-Bromo-2-hydroxy-3-methoxybenzaldehyde ligand involving heteronuclear complex, [Cu(L)Hg(Cl)2]. X-ray single-crystal determined the complex crystal structure and characterized it by various physical methods, including elemental, FT-IR, Raman, PXRD, UV–vis, NMR, and SEM-EDX techniques. X-ray diffraction analysis reveals that the compound adopts a monoclinic space group Cc during crystallization. The crystal structure exhibits unique supramolecular interactions, like intermolecular C-H∙∙∙π H-bonding and X-bonding (X = Halogen) between Br(1) and Br(2) atoms. Hirshfeld surfaces (HS) and 2-D fingerprint plots confirm significant H…Cl (21.9 %) contacts. Further, dispersion energy dominates due to Br atoms' higher electron/electron cloud. The complex underwent DFT calculations based on the Gaussian software package at B3LYP, HF, and M062x levels, utilizing the lanl2dz, sdd, and def2tzvp basis sets. The HOMO-LUMO, ESP, Global reactivity, Interaction energy and energy frameworks, and Fukui function investigated the complex properties in a multidimensional spectrum. The complex showed promising NLO activity, which has broad technological applications. Fukui function calculation identifies regions prone to nucleophilic (Nu-) and electrophilic (E+) attacks. The complex and synthetic components were examined for antimicrobial function against Gram+ve and Gram-ve bacterial and fungal strains. Molecular docking (MD) and Protein-Ligand Interaction Profilers (PLIP) further support the antimicrobial findings.