Copper complexes formed by 3,5-bis(2,2′-bipyridin-4-ylethynyl)benzoic acid and its methyl and ethyl esters as studied by electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry was used to study the complexes of ligands containing two bipyridine units, namely 3,5-bis(2,2-bipyridin-4-ylethynyl)benzoic acid (1) and its methyl and ethyl esters (2, 3), with copper cation, with CuCl₂ as a source of copper. It was found that the type of complexes formed strongly depends on CuCl₂ concentration. At lower CuCl₂ concentration, the detected complexes were rather simple and some of them were formed upon electrospray ionization conditions e.g. ions [2₂+Cu₂]²⁺ and [3₂+Cu₂]²⁺ (complexes ligand-Cu(I) of stoichiometry 2:2) which are analogical to the well known, for quaterpyridine, helical complexes. At higher CuCl₂ concentration, the detected complexes were more complicated, and most of them contained copper cations bridged by chlorides. The largest ions were [L₂+Cu₄Cl₆]²⁺. The CID MS/MS spectra of these ions allowed determination of their mass spectrometric fragmentation pathways and as a consequence their structure elucidation.      

Synthesis and characterization of copper(II) hexaazamacrotetracyclic complexes containing organic ligands

Two mononuclear copper(II) complexes [Cu(L)(NO₂)](ClO₄) (1) and [Cu(L)(MO₄)]₂· 5H₂O (2) (L = 1,3,10, 12,16,19-hexaazatetracyclo[17,3,1,1^12.16,0^4.9]tetracosane) have been synthesized and their structures determined. Both compounds show a distorted square-pyramidal geometry with the two secondary and two tertiary amines of the macrocycle and one ligand coordinated at the axial position. Cyclic voltammetry of the complexes gives two one-electron waves corresponding to Cu^II/Cu^III and Cu^II/Cu^I processes. The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature of the organic ligands.     

Copper(II) complexes with neutral bis(pyrazolyl)methane ligands: The influence of steric hindrance on their structures and properties

By using the neutral bidentate nitrogen-containing ligands; bis(3,5-dimethyl-1-pyrazolyl)methane (L0″), bis(3,5-diisopropyl-1-pyrazolyl)methane (L1″), bis(3-tertiary-butyl-5-isopropyl-1-pyrazolyl)methane (L3″), and bis(3,5-ditertiary-butyl-1-pyrazolyl)methane (L4″), the copper(II) nitrato complexes [Cu(L0″)₂(NO₃)]NO₃ (1NO₃), [Cu(L0″)(NO₃)₂] (2), [Cu(L1″)(NO₃)₂] (3), [Cu(L3″)(NO₃)₂] (4), and [Cu(L4″)(NO₃)₂] (5), chloro complexes [Cu(L0″)₂Cl]₂(CuCl₄) (6CuCl₄), [Cu(L0″)₂Cl]₂(Cu₂Cl₆) (6Cu₂Cl₆), [Cu(L1″)Cl₂] (7), and [Cu(L3″)Cl₂] (8), nitrito complexes [Cu(L0″)(ONO)₂] (9) and [Cu(L1″)(ONO)₂] (10), and the complexes with perchlorate ions [Cu(L0″)₂(CH₃OH)](ClO₄)₂ (11ClO₄) and [Cu(L1″)₂(H₂O)](ClO₄)₂ (12ClO₄) were systematically synthesized and fully characterized by X-ray crystallography and by IR, far-IR, UV–Vis absorption, and ESR spectroscopy. In comparison with the obtained complexes with four bis(pyrazolyl)methanes having different bulkiness at pyrazolyl rings, the second coordination sphere effects on the ligands are discussed in detail. Moreover, the structures and physicochemical properties of these obtained complexes are compared with those of the related complexes with the neutral tridentate tris(pyrazolyl)methane ligand.     

Copper(II), nickel(II) and zinc(II) complexes ofN,N′, N″, N‴-tetra(2-cyanoethyl)-1,4,8, 12-tetra-azacyclopentadecane

Summary Reaction of 1,4,8, 12-tetra-azacyclopentadecance ([15])-aneN₄) with an excess of acrylonitrile gives theN-tetracyanoethylated ligand (L). Several new complexes of this ligand with nickel(II), copper(II) and zinc(II) have been prepared and characterised. The complexes can be formulated [NiL]_n(ClO₄)_2n, [ML](ClO₄)₂ (M=Cu^II and Zn^II), [NiL(NCS)₂], [NiLCl₂], [CuL](NO₃)₂ and [NiL]_n(NO₃)_2n·2H₂O. Spectral, magnetic and conductivity data are reported and possible structures are considered.     

Trace Amounts of Aqueous Copper(II) Chloride Complexes in Hypersaline Solutions: Spectrophotometric and Thermodynamic Studies

Knowledge of the thermodynamic properties of aqueous copper(II) chloride complexes is important for understanding and quantitatively modeling trace copper behavior in hydrometallurgical extraction processing. In this paper, UV–Vis spectra data of Cu(II) chloride solutions with various salinities (NaCl, 0–5.57 mol·kg^?1) are collected at 25 °C. The concentration distribution of Cu–Cl species is in good agreement with those calculated by a reaction model (RM). The simple hydrated ion, Cu²⁺, is dominant at low concentration, whereas [CuCl]⁺, [CuCl₂]⁰ and [CuCl₃]^? become increasingly important as the chloride concentration rises. Moreover, the RM calculation suggests the present of a small amount of [CuCl₄]^2?. The de-convoluted molar spectrum of each species is in excellent agreement with our previous theoretical results predicted by time-dependent density functional theory treatment of aqueous Cu-containing systems. The formation constants for these copper chloride complexes have been reported and are to be preferred, except log₁₀ K ₂ ([CuCl₂]⁰).     

Electrochemical Examination of Copper(II) Complexes with Octaazamacrocyclic Ligand and Heterocyclic Dithiocarbamate

Mixed ligand dinuclear copper(II) complexes of the general formula [Cu₂(Rdtc)tpmc)](ClO₄)₃ with octaazamacrocyclic ligand tpmc and four different heterocyclic dithiocarbamate ligands Rdtc^?, as well as the complexes [Cu₂(tpmc)](ClO₄)₄ and [Cu(tpmc)](ClO₄)₂?2H₂O were studied in aqueous NaClO₄ and HClO₄ solutions by cyclic voltammetry on glassy carbon electrode. The electrochemical properties of the ligands and Cu(II) complexes were correlated with their electronic structure. Conductometric experiments showed different stoichiometry in complexation of tpmc with Cu²⁺ ions and transport of ions in acetonitrile and in aqueous media. These studies clarified the application of this macrocyclic ligand as ionophore in a PVC membrane copper(II) selective electrode and contributed elucidation of its sensor properties.     

Syntheses,equilibrium, and structural studies of copper(II) and nickel(II) complexes with a tripodal alanine-based ligand

A heptadentate ligand, tris[(L)-alanyl-2-carboxamidoethyl]amine (H₃trenala), has been synthesized as its tetrahydrochloride salt; its protonation constants and the stability constants of the copper(II) and nickel(II) chelates have been determined by potentiometry. Mononuclear species with protonated, neutral, or deprotonated forms of the ligand, [Cu(H₅trenala)]⁴⁺, [M(H₄trenala)]³⁺, [M(H₃trenala)]²⁺, [M(H₂trenala)]⁺, and [M(Htrenala)] (M?=?Cu²⁺ and Ni²⁺) have been detected in all cases, while only Cu²⁺ gives dinuclear [Cu₂(H₂trenala)]²⁺, [Cu₂(Htrenala)]²⁺, [Cu₂(trenala)]⁺, and [Cu₂(trenala)(OH)] species. Two dinuclear copper(II) complexes have been prepared and characterized by spectroscopic techniques (IR, UV-Vis, mass electro-spray) and thermogravimetric analysis.     

Phenylcopper(I) clusters in the gas phase obtained by laser desorption/ionization from bis(dibenzoylmethane)copper(II)

It has been demonstrated that phenylcopper(I)-containing clusters are generated in the gas phase from bis(dibenzoylmethane) copper(II) (Cu(dbm)₂) by laser desorption/ ionization (LDI) method. For example, the [Cu₅dbm₂(C₆H₅)₂]⁺ ion can be considered as consisting of two Cudbm molecules, two CuC₆H₅ molecules and a Cu⁺ cation. The [Cu₅(C₆H₅)₄]⁺ ion can be considered as phenylcopper(I) cluster (consisting of four phenylcopper molecules) ionized by additional Cu⁺ cation. Results from MS/MS (tandem mass spectrometry) experiments have confirmed the presence of phenylcopper molecules in the analyzed clusters. Ease of preparation of dibenzoylmethane-metal complexes and straightforward method to obtain LDI mass spectra offer a wide range of possibilities to study similar organometallic clusters in the gas phase.      

Low-temperature activation of nitrogen oxide on Cu-ZSM-5 catalysts

The adsorption and activation of NO molecules on Cu-ZSM-5 catalysts with different Cu/Al and Si/Al ratios (from 0.05 to 1.4 and from 17 to 45, respectively) subjected to different pretreatment was studied by ultraviolet-visible diffuse reflectance (UV-Vis DR). It was found that the amount of chemisorbed NO and the catalyst activity in NO decomposition increased with an increase in the Cu/Al ratio to 0.35–0.40. The intensity of absorption bands at 18400 and 25600 cm⁻¹ in the UV-Vis DR spectra increased symbatically. It was hypothesized that the adsorption of NO occurs at Cu⁺ ions localized in chain copper oxide structures with the formation of mono- and dinitrosyl Cu(I) complexes, and this process is accompanied by the Cu²⁺...Cu⁺ intervalence transfer band in the region of 18400 cm⁻¹. The low-temperature activation of NO occurs through the conversion of the dinitrosyl Cu(I) complex into the π-radical anion (N₂O₂)⁻ stabilized at the Cu²⁺ ion of the chain structure, [Cu²⁺-cis-(N₂O₂)⁻], by electron transfer from the Cu⁺ ion to the cis dimer (NO)₂. This complex corresponds to the L → M charge transfer band in the region of 25600 cm⁻¹. The subsequent destruction of the complex [Cu²⁺-cis-(N₂O₂)⁻] at temperatures of 150–300°C leads to the release of N₂O and the formation of the complex [Cu²⁺O⁻], which further participates in the formation of the nitrite-nitrate complexes [Cu²⁺(NO₂)⁻], [Cu²⁺(NO)(NO₂)⁻], and [Cu²⁺(NO₃)⁻] and NO decomposition products.     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

Chemical characteristics of the products of the complexation reaction between copper(II) and a tetra-aza macrocycle in the presence of chloride ions

The reaction of copper(II) perchlorate with the hydrochloride salt of 3,6,9,15-tetra-azabicyclo[9.3.1]penta-deca-1,11,13-triene (L1) in acetonitrile forms two macrocyclic complexes that can be characterized: [L1Cu^IICl][ClO₄] (1) and [L1Cu^IICl]₂[CuCl₄] (2). The structural, electronic, and redox properties of these complexes were studied using spectroscopy (EPR and UV–visible) and electrochemistry. In addition, the solid-state structure of 1 was obtained using X-ray diffraction. The copper(II) is five-coordinate ligated by four N-atoms of the macrocycle and a chloride atom. EPR studies of 1 both in DMF and aqueous solution indicate the presence of a single copper(II) species. In contrast, EPR studies of 2 performed in frozen DMF and in the solid-state reveal the presence of two spectroscopically distinct copper(II) complexes assigned as [L1Cu^IICl]⁺ and [Cu^IICl₄]^2?. Lastly, electrochemical studies demonstrate that both [L1Cu^IICl]⁺ and [Cu^IICl₄]^2? are redox active. Specifically, the [L1Cu^IICl]⁺ undergoes a quasi-reversible Cu(II)/(I) redox reaction in the absence of excess chloride. In the presence of chloride, however, the chemical irreversibility of this couple becomes evident at concentrations of chloride that exceed 50 mM. As a result, the presence of chloride from the chemical equilibrium of this latter species impedes the reversibility of the reduction of [L1Cu^IICl]⁺ to [L1Cu^ICl]⁰.     

Neue Kupfer(I,II)-Verbindungen

New Copper(I, II) Compounds Complexes of the type [Cu^II(N∩N)₂][Cu^ICl_1+x]_2x (N∩N = en, pn, 2-amino picoline) are prepared from Cu(N∩N)₂Cl₂ and copper(I) chloride. [Cu^II(enac)][Cu^ICl₂]₂ — a complex with a macrocyclic cation — is obtained, by the reaction of Cuen₂Cl₂ in aqueous acetone. Diacetyl monoxime partially reduces copper(II) of Cu(NSMe)₂Cl₂ and in this way causes the formation of [Cu(NSMe)_2][CuCl₃] (NSMe = β-aminoethyl methylsulfide). On the other hand a template reaction of this oxime with Cu(NSMe)₂ (ClO₄)₂ produces Cu^II(ONNSMe)(ClO₄) (HONNSMe?CH₃C(NOH)C(NCH₂CH₂SCH₃)CH₃), which shows a reduced paramagnetism. Basing on magnetic behaviour, i. r. and vis spectra the structure of the new compounds is discussed.     

New mononuclear copper(II) complexes from β-diketone and β-keto ester N-donor heterocyclic ligands: structure,bioactivity, and molecular simulation studies

Four new mononuclear copper(II) complexes with methyl acetoacetate and benzoylacetone in the presence of 1,10-phenanthroline and 2,2′-bipyridine were synthesized and characterized by elemental analyses, FT-IR, and UV–Vis spectroscopy. The molecular structures of complexes [Cu(MAA)(bpy)(ClO₄)] (1a), [Cu(bzac)(bpy)]ClO₄ (2a), [Cu(MAA)(phen)(ClO₄)] (1b) and [Cu(bzac)(phen)(ClO₄)] (2b) were determined by single crystal X-ray diffraction technique. 1a, 1b, and 2b are five coordinate with a distorted square pyramidal geometry and the structure of 2a consists of isolated [Cu(bzac)(bpy)]⁺ cations and perchlorate counter anions. The electrochemical studies of copper complexes in acetonitrile solution showed that Cu^II/Cu^I reduction processes are electrochemically irreversible. Cytotoxic activity of complexes was screened, including an MTT assay against gastric cancer cell line (MKN-45). The four Cu(II) complexes exhibited lethal effects against MKN-45 cell lines and the half maximal inhibitory concentration (IC₅₀) values obtained were much lower in comparison with 5-fluorouracil. In addition, MTT and migration studies revealed that benzoylacetone complexes are more active than complexes of methyl acetoacetate against the MKN-45 cancer cell lines. Docking simulations of Cu(II) complexes on DNA revealed that the most stable adducts with DNA bind in the minor groove. All complexes display a binding specificity to the A/T rich regions.     

Copper(II) complexes of tetradentate N2S2 donor sets: Synthesis,crystal structure characterization and reactivity

Two mononuclear and one dinuclear copper(II) complexes, containing neutral tetradentate NSSN type ligands, of formulation [Cu^II(L¹)Cl]ClO₄ (1), [Cu^II(L²)Cl]ClO₄ (2) and [Cu^II₂(L³)₂Cl₂](ClO₄)₂ (3) were synthesized and isolated in pure form [where L¹ = 1,2-bis(2-pyridylmethylthio)ethane, L² = 1,3-bis(2-pyridylmethylthio)propane and L³ = 1,4-bis(2-pyridylmethylthio)butane]. All these green colored copper(II) complexes were characterized by physicochemical and spectroscopic methods. The dinuclear copper(II) complex 3 changed to a colorless dinuclear copper(I) species of formula [Cu^I₂(L³)₂](ClO₄)₂,0.5H₂O (4) in dimethylformamide even in the presence of air at ambient temperature, while complexes 1 and 2 showed no change under similar conditions. The solid-state structures of complexes 1, 2 and 4 were established by X-ray crystallography. The geometry about the copper in complexes 1 and 2 is trigonal bipyramidal whereas the coordination environment about the copper(I) in dinuclear complex 4 is distorted tetrahedral.     

Heterometallic copper-lanthanum complexes of 4-(1H)-pyridone

Summary Reaction of Cu(OAc)₂, 4-(1H)-pyridone (LH) and Dy or Gd nitrate in MeOH resulted in the formation of the heterometallic complexes [Cu₂LnL₂(LH)₂(NO₃)(OH)₄· xH₂O], Ln = Dy (1) or Gd (2). Reaction of Cu(OH)₂ with 4-(1H)-pyridone and Dy(NO₃)₃ in DMF resulted in the formation of the heterometallic compound [Cu₂DyL₂(LH)₂(NO₃)₂(OH)₃·DMF] (3). The Cu complexes [Cu(OAc)L]₂ and [CuL₂·DMF] _x have also been prepared from the reaction of 4-(1H)-pyridone with Cu²⁺ in MeOH and DMF, respectively. All the complexes were characterized by elemental analyses, and i.r. and X-band e.s.r. spectroscopies.     

Unexpected complexation of allylpseudothiohydantoin hydrochlorides towards CuX (X = Cl,NO3, ClO4, BF4, 1/2SiF6). The first known examples of joint CuI(Cl,ClO4) and CuI(Cl,BF4) π-complexes

By means of alternating current-electrochemical synthesis starting from a mixture of 2-imino-3-(prop-2-en-1-yl)-1,3-thiazolidin-4-one (3-allylpseudothiohydantoin, napt) and 2-allylamino-1,3-thiazol-4(5H)-one (allylaminopseudothiohydantoin, aapt) hydrochlorides and corresponding copper(II) salts five new π-complexes, [Cu(napt)Cl] (1), [Cu₂(aapt)₂Cl]NO₃ (2), [Cu₂(aapt)₂Cl]BF₄ (3), [Cu₂(aapt)₂Cl]ClO₄ (4) and [Cu₂(aapt)₂Cl]₂SiF₆·2H₂O (5), were obtained and studied by X-ray single crystal diffraction and IR-spectroscopy. Napt and aapt molecules are selectively coordinated to Cu⁺ depending on the anion type. In crystals of 1 and 5, the organic ligands are attached to the metal in a chelating N,(C=C)-bidentate mode. The aapt molecule in 2-4 acts as a tridentate chelating ligand, being coordinated to the copper(I) ion through the heterocyclic N atom, carbonyl O atom, and C=C bond of allyl group, forming an original cationic [Cu₂(aapt)₂Cl]⁺ fragment with both a bridging Cl^– ion and O atom of the C=O group. In the presence of the doubly charged SiF₆^2– anion, Cu(I) in 5 prefers to be bonded with two bridging Cl^– ions, rather than the C=O group, causing [Cu₂(aapt)₂Cl]⁺ units to associate into the infinite cationic chains. Crystals of 3 and 4 are the first known examples of the simultaneous BF₄^–/Cl^– or ClO₄^–/Cl^– participation in copper(I) π-complex formation.     

Synthesis and Magnetism of Copper(II)-lanthanide(III)-copper(II) Heterotrinuclear Complexes with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis [2-(dimethylamino)ethyl]oxamidocopper(II)

Nine new μ-oxamido-bridged copper(II)-lanthanide(III)-copper(II) heterotrinuclear complexes described by the overall formula Cu₂(dmoxae)₂Ln(NO₃)₃ {Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er; dmoxae = N,N′-bis[2-(dimethylamino)ethyl]oxamido dianions} have been synthesized by the strategy of ‘complex as ligand’, and characterized by elemental analyses, molar conductivity measurements, i.r. and electronic spectral studies. The variable-temperature susceptibility (2–300 K), e.s.r. measurements, and studies of the Cu₂(dmoxae)₂Gd(NO₃)₃ complex have revealed that the central gadolinium(III) and terminal copper(II) ions are ferromagnetically coupled with the exchange integral J_(Cu-Gd) = +2.1 cm⁻¹, while an antiferromagnetic coupling is detected between the terminal copper(II) ions with J′_(Cu-Cu)=−0.36 cm⁻¹, on the basis of the spin Hamiltonian operator . A plausible mechanism for the ferromagnetic coupling between copper(II) and gadolinium(III) is discussed in terms of spin polarization.     

Magnetic properties of transition metal complexes with 2,2′-bipyridin-5-yl t-butyl nitroxide

Complexes [Mn^II(5bpno)₃(ClO₄)₂], [Mn^II(5bpno)(CH₃OH)₂Cl₂], [Cu^II(5bpno)₂(ClO₄)₂], and [Cu^II(5bpno)Cl₂] were prepared, where 5bpno stands for 2,2′-bipyridin-5-yl t-butyl nitroxide. X-ray crystallographic analysis clarified that the Cu ion in [Cu(5bpno)₂(ClO₄)₂] was tetra-coordinate with four nitrogen atoms forming two chelate rings. Magnetic measurements revealed the presence of ferromagnetic couplings in the Mn complexes, whereas the Cu complexes showed antiferromagnetic couplings. Magnetic exchange couplings between the metal and radical spins through the intervening pyridine ring can be explained in terms of the spin-polarization mechanism.     

A new copper(II) coordination polymer containing chains of interconnected paddle‐wheel antiferromagnetic clusters

The construction of supramolecular architectures based on inorganic–organic coordination frameworks with weak noncovalent interactions has implications for the rational design of functional materials. A new crystalline binuclear copper(II) one‐dimensional polymeric chain, namely catena‐poly[[[tetrakis(μ‐4‐azaniumylbutanoato‐κ²O :O ′)dicopper(II)(Cu —Cu )]‐μ‐chlorido‐[diaquadichloridocopper(II)]‐μ‐chlorido] bis(perchlorate)], {[Cu₃Cl₄(C₄H₉NO₂)₄(H₂O)₂](ClO₄)₂}_n , was obtained by the reaction of 4‐aminobutyric acid (GABA) with CuCl₂·2H₂O in aqueous solution. The structure was established by single‐crystal X‐ray diffraction and was also characterized by IR spectroscopy and magnetic measurements. The crystal structure consists of [{Cu₂(GABA)₄}{CuCl₄(H₂O)₂}]⁺ cations and isolated perchlorate anions. Two symmetry‐related Cu^II centres are bridged via carboxylate O atoms into a classical paddle‐wheel configuration, with a Cu…Cu distance of 2.643 (1) Å, while bridging Cl atoms complete the square‐pyramidal geometry of the metal atoms. The Cl atoms connect the paddlewheel moieties to a second Cu^II atom lying on an octahedral site, resulting in infinite helical chains along the c axis. The packing motif exhibits channels containing free perchlorate anions. The crystal structure is stabilized by hydrogen bonds between the perchlorate anions, the coordinated water molecules and the ammonium groups of the polymeric chains. The magnetic analysis of the title compound indicates a nontrivial antiferromagnetic behaviour arising from alternating weak–strong antiferromagnetic coupling between neighbouring Cu^II centres.     

Preparation, characterization and crystal structures of copper(II) hexaazamacrotetracyclic complexes with organic ligands

The reaction of [Cu(L)](ClO₄)₂ · H₂O (L=1,3,10,12,16,19-hexaazatetracyclo[17,3,1,1^12.16,0^4.9]tetracosane) with NaN₃ and Na₂tp yields mononuclear and dinuclear copper(II) complexes, [Cu(L)(N₃)](ClO₄) (1) and [Cu(L)(μ-tp)](ClO₄) · 2H₂O (2). These complexes have been characterized by X-ray crystallography, electronic absorption, cyclic voltammetry and magnetic susceptibility. The crystal structure of (1) shows that the copper(II) ion has a distorted square-pyramidal geometry with the two secondary and two tertiary amines of the macrocycle and one nitrogen atom from the azide group coordinating the axial position. The copper(II) ions in (2) are bridged by the terephthalate anion to form a dinuclear complex, in which each copper(II) ion reveals a distorted square-pyramid with four nitrogen atoms of the macrocycle and the oxygen atom of bridging tp ligand. Cyclic voltammetry of the complexes gives two one-electron waves corresponding to Cu^II/Cu^III and Cu^II/Cu^I processes. The magnetic susceptibility measurement for (2) exhibits a weak antiferromagnetic interaction between copper(II) centers with a 2J value of −2.21 cm⁻¹ (H = −2JΣS₁ · S₂). The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature of the organic ligands.