Hexakis(prop‐2‐enamide)copper(II) bis(perchlorate) and hexakis(prop‐2‐enamide)manganese(II) bis(perchlorate)

The structures of [Cu(AA)₆](ClO₄)₂, (I), and [Mn(AA)₆](ClO₄)₂, (II) (AA is acrylamide, also known as prop‐2‐enamide; C₃H₅NO), display both intra‐ and intermolecular N—H...O hydrogen bonding. A three‐dimensional network is propagated via the perchlorate counter‐ions. There are two crystallographically independent molecules in the copper complex, with the most significant difference between them being the conformation of one symmetry‐related pair of AA ligands which are in the unusual syn conformation. The copper complex exhibits syn/anti disorder of the =CH₂ group in one pair of symmetry‐related AA ligands. The Cu^II and Mn^II centres are both situated on centres of inversion. The copper complex cation has octahedral coordination geometry with typical Jahn–Teller distortions.     

ELECTRONIC STRUCTURES AND BONDING PROPERTIES OF MIXED LIGAND COPPER(II) COMPLEXES OF 2-(2-PYRIDYLETHYL)PICOLYLAMINE AND DIPICOLYLAMINE. MOLECULAR STRUCTURES OF (2,2′-BIPYRIDINE)[2-(2-PYRIDYLETHYL)PICOLYLAMINE]COPPER(II) PERCHLORATE AND (DIPICOLYLAMINE)(1,10-PHENANTHROLINE)COPPER(II) PERCHLORATE

Abstract

Mixed ligand copper(II) complexes of 2-(2-pyridylethyl)picolylamine (pepica) of [Cu(pepica)(pi-colinato)](ClO₄)(H₂O) and the [Cu(pepica)(L)](ClO₄)₂ type, where L stands for 2,2′-bipyridine (bipy), 1,10-phenanthroline, neocuproine, and ethylenediamine, and dipicolylamine(dipica) of the [Cu(dipica)(L)](ClO₄)₂(H₂O) _n type, where L for 2,2′-bipyridine (n = 0), 1,10-phenanthroline (phen, n = 0), and neocuproine (n = 1), have been synthesized and characterized by elemental analyses, and IR, electronic and EPR spectroscopic measurements. The molecular structures of [Cu(pepica)(bipy)](ClO₄)₂ (1) and [Cu(dipica)(phen)](ClO₄)₂ (2) have been determined using three dimensional X-ray diffraction data. Complex 1 consists of discrete distorted square pyramidal [Cu(pepica)(bipy)] cations, with a meridional pepica ligand and one of the pyridine rings of the bipy ligand forming a basal plane. The other pyridine nucleus of the bipy is bound at the apex having an elongated bond distance of 2.255 Å and tilted off the normal z axis by ～15°. Complex 2 comprises discrete distorted trigonal bipyramidal [Cu(dipica)(phen)] cations, with the two pyridine nuclei of the dipica ligand and one of the pyridine rings of the phen forming an equatorial trigonal plane and the remaining pyridine ring of the phen and the amine nitrogen of the dipica on the axial sites. The trigonal bipyramidal cation, distorted toward a square pyramidal structure, has an enlarged equatorial N(py)–Cu–N(py) angle of 132.4° and an elongated equatorial Cu–N(phen) bond of 2.156 Å. All of the complexes exhibit axial type EPR spectra. Gaussian resolved d-d spectra for these complexes, except the dipica-bipy and dipicaphen ones, yield an orbital sequence of d_x ²- _y ² ≥ d_z ² > d_xy > d_yz ～d_xz . The bonding properties of the tridentate and the bidentate ligands are elucidated.     

Copper(II) perchlorate complexes with antipyrine: synthesis,structure, cytotoxicity and DFT calculations

The synthesis, structure and properties of copper(II) perchlorate complexes with antipyrine (AP), [Cu(AP)₄(H₂O)](ClO₄)₂ and [Cu(AP)₅](ClO₄)₂, are described and compared with those of alternative compounds containing different AP ligands.     

Synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes with bis [(diphenylphosphinyl)methyl] phenylphosphine oxide,bis [(disphenylphosphinyl)methyl]ethyl phosphinate,and bis [(diphenylphosphinyl)methyl] phosphinic acid

The synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes containing bis [(diphenylphosphinyl)methyl] [phenylphosphine oxide (RPPH), bis [(diphenylphosphinyl)methyl] ethyl phosphinate (RPOEt), and bis [(diphenylphosphinyl)methyl] phosphinic acid (RPOH) have been studied. The substituent at the central phosphorus atom of the ligand is responsible for the types of complexes formed. The new complexes [M(RPPh)₂(ClO₄)₂.nH₂O, [M(RPPh)₃](ClO₄)₂.4H₂O, [M(RPOEt)₂](ClO₄)₂.2H₂O, and [M(RPOH)₃] (ClO₄)₂.nH₂O are characterized as high spin and most of them have an octahedral or distorted octahedral geometry [M = Co(II), Ni(II), or Cu(II); n = 2?5]. The coordination of two P = O groups from one ligand to the metal has been proposed for most of the complexes formed. The coordination of all three P = O groups has been assumed for complexes [M(RPPh)₂](ClO₄)₂.nH₂O and [M(RPOEt)₂](ClO₄)₂.2H₂O.     

A copper(II)–pyrazole complex cation with imposed symmetry

The reaction of Cu(ClO₄)₂·6H₂O, NaAsF₆ and excess pyrazole yields hexakis­(pyrazole‐κN²)copper(II) bis­(hexa­fluoroarsenate), [Cu(C₃H₄N₂)₆](AsF₆)₂ or [Cu(pzH)₆](AsF₆)₂ (pzH is pyrazole), (I). The analogous hexakis­(pyrazole‐κN²)copper(II) hexafluorophosphate perchlorate complex, [Cu(C₃H₄N₂)₆](PF₆)_1.29(ClO₄)_0.71 or [Cu(pzH)₆](PF₆)_1.29(ClO₄)_0.71, (II), is obtained in a similar fashion, using KPF₆ in place of NaAsF₆. Both compounds contain the hitherto unknown [Cu(pzH)₆]²⁺ complex cation, in which the copper(II) ion lies at the center of a regular octahedron of coordinated N atoms. The cation has crystallographically imposed symmetry. The X‐ray data indicate that the lack of the expected distortion can be accounted for by the presence of either static Jahn–Teller disorder or dynamic Jahn–Teller distortion.     

Nickel(II) and copper(II) complexes of 2-(2-pyridyl)benzimidazole: synthesis and structural characterization

2-(2-Pyridyl)benzimidazole (PBI) was synthesized by solvent-free aldol condensation and complexed with nickel(II) and copper(II) nitrate and perchlorate salts by simple reactions at room temperature. The transition metal complexes [Ni(PBI)₂NO₃](NO₃) (1), [Ni(PBI)₃](ClO₄)₂·1.5H₂O (2), [Cu(PBI)₂NO₃](NO₃) (3), and [Cu(PBI)₃](ClO₄)₂·3H₂O (4) (PBI = 2-(2-pyridyl)benzimidazole) were synthesized in good yield and structurally characterized by X-ray crystallography, infrared absorption spectroscopy, and elemental analysis. Complexes 1 and 3 are isostructural, crystallizing in the same space group P2₁/c. Both the nickel(II) and copper(II) atoms have distorted square pyramidal geometries. The metal centers in these complexes are coordinated by two molecules of the bidentate ligand (PBI) and an O-atom of the coordinated nitrate anion. Complexes 2 and 4 are also isostructural but do not crystallize in the same space group: P-1 for 2 and Pccn for 4. The geometry around both the nickel(II) and the copper(II) centers is distorted octahedral. Here, the metal atoms are coordinated by three molecules of 2-(2-pyridyl)benzimidazole. The copper(II) complex 4 has 2-fold symmetry with one of the three PBI ligands being positionally disordered about the 2-fold axis. Intermolecular N–H···O hydrogen bonds, involving the NH H-atom and an O-atom of the coordinated nitrate anion, are observed in all four complexes. In 1 and 3, this gives rise to the formation of centrosymmetric dimer-like structures that are decorated by hydrogen-bonded nitrate anions. In 2 and 4 the perchlorate anions and the water molecules of crystallization are involved in N–H···O and O–H···O hydrogen bonds bridging two symmetry-related cations, thus forming cyclic arrangements. In the case of complex 4, this leads to the formation of two-dimensional hydrogen-bonded networks parallel to plane (011). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Uncommon isonicotinamide supramolecular synthons in copper(II) complexes directed by nitrate and perchlorate anions

The title compounds, trans‐diaquabis(nitrato‐κO)bis(pyridine‐4‐carboxamide‐κN¹)copper(II), [Cu(NO₃)₂(C₆H₆N₂O)₂(H₂O)₂], (I), and trans‐diaquatetrakis(pyridine‐4‐carboxamide‐κN¹)copper(II) bis(perchlorate), [Cu(C₆H₆N₂O)₄(H₂O)₂](ClO₄)₂, (II), are composed of mononuclear coordination entities involving Cu^II ions and isonicotinamide. In (I), the centrosymmetric tetragonally distorted octahedral copper(II) environment contains trans‐related isonicotinamide and water molecules in the equatorial plane and two nitrate ions occupying the axial sites. In (II), the equatorial plane of the C₂‐symmetric distorted octahedron is built up of four isonicotinamide ligands, while water molecules occupy the axial positions. The complex molecules of (I) and (II) are linked into three‐dimensional supramolecular frameworks by O—H...O and N—H...O hydrogen bonds. The nitrate and perchlorate ions are building blocks that disturb the robust R₂²(8) amide supramolecular motif commonly found in crystal structures of copper–isonicotinamide complexes.     

Ni(II), Pd(II), Cu(II) And Zn(II) complexes with N-(2-Pyridyl)Carbonylaniline (L), Syntheses and X-Ray Crystal structures of [Cu(L)2(H2O)2](No3)2, [Cu(L)2(H2O)2](Clo4)2 and [Zn(L)2(H2O)2](Clo4)2

Reaction of the N-(2-pyridyl)carbonylaniline ligand (L) with Cu(NO₃)₂, Cu(ClO₄)₂, Zn(ClO₄)₂, Ni(NO₃)₂ and PdCl₂ gives complexes with stoichiometry [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, [Zn(L)₂(H₂O)₂] (ClO₄)_2, [Ni(L)₂(H₂O)Cl](NO₃) and PdLCl₂. The new complexes were characterized by elemental analyses and infrared spectra. The crystal structures of [Cu(L)₂(H₂O)₂](NO₃)₂, [Cu(L)₂(H₂O)₂](ClO₄)₂, and [Zn(L)₂(H₂O)₂](ClO₄)₂ were determined by X-ray crystallography. The cation complexes [M(L)₂(H₂O)₂] contain copper(II) and zinc(II) with distorted octahedral geometry with two N-(2-pyridyl)carbonylaniline (L) ligands occupying the equatorial sites. The hexa-coordinated metal atoms are bonded to two pyridinic nitrogens, two carbonyl oxygens and two water molecules occupying the axial sites. Both the coordinated water molecules and uncoordinated amide NH groups of the N-(2-pyridyl)carbonylaniline (L) ligands are involved in hydrogen bonding, resulting in infinite hydrogen-bonded chains running in one and two-dimensions.     

Effect of the type of crystal lattice in nickel(II) and copper(II) macrocyclic carboxylates on absorption of copper amine complexes from solutions

We have established that crystalline nickel-containing metal–organic frameworks (MOFs) bind the complex [Cu(NH₃)₄](ClO₄)₂ from acetonitrile solutions and do not react with [Cu(en)₂](ClO₄)₂. The MOF/copper ammine complex ratio in the products after reaching saturation is determined by the crystal lattice structures of the compounds, and increases from 1.2 (one-dimensional coordination polymer, 1D CP) to 3.2 (2D CP)and 3.9 (ionic MOF) moles of copper ammine complex per formula unit of sorbent. We have shown that it is possible to convert the bound ammine complex to nanosized copper(II) sulfide by treatment with sodium sulfide.     

Syntheses and crystal structures of copper(II) and nickel(II) complexes derived from 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol

A new centrosymmetric mononuclear copper(II) complex [Cu(L)₂](ClO₄)₂ (I) and a new centrosymmetric mononuclear nickel(II) complex [Ni(L)₂(MeOH)₂](ClO₄)₂ (II), where L is the zwitterionic ligand 2-bromo-4-chloro-6-[(2-methylammonioethylimino)methyl]phenolate, have been prepared from the Schiff base 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol with copper perchlorate and nickel perchlorate, respectively. The complexes were characterized by elemental analysis, infrared spectra, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408054 (I) and 1407973 (II)). Complex I crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.7736(4), b = 21.608(1), c = 8.5194(4) Å, β = 93.907(2)°, V = 1427.7(1) ų, Z = 2, R ₁ = 0.0546, and wR ₂ = 0.1531. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 21.324(3), b = 16.821(2), c = 9.425(1) Å, β = 90.114(2)°, V = 3380.5(7) ų, Z = 4, R ₁ = 0.0693, and wR ₂ = 0.1627. The Cu atom in I is in square planar coordination, and the Ni atom in II is in octahedral coordination.     

Complexes of copper(II) with diazabutadienes

Summary Studies on the chelate complexes of copper(II) with the bidentate ligands, 1,4-diphenyl-2,3-dimethyl-1,4-diazabutadiene (PMB) and 1,4-di(p-methoxyphenyl)-2,3-dimethyl-1,4-diazabutadiene (MPMB), have been carried out. On the basis of the elemental analysis and molar conductivity, the complexes have been characterized as [Cu(PMB)Cl₂], [Cu(PMB)₂](ClO₄)₂, [Cu(MPMB)Cl₂] and [Cu(MPMB)₂](ClO₄)₂. Both diazabutadienes are bidentate via nitrogen atoms. The temperature dependence of the magnetic susceptibility and the electron paramagnetic resonance, i.r. and u.v.-vis spectra are reported. All compounds appear to be monomers.     

Synthesis,crystal structure and physicochemical properties of copper(II) complexes containing bis[(benzimidazol-2-yl)methyl] ether derivatives

A new benzimidazoyl ligand bis[(N-ethylbenzimidazol-2-yl)methyl]ether (EDGB) and Cu^II complexes [Cu(L¹) (L²)](ClO₄)·mEt₂O·nH₂O [L¹ = bis[(benzimidazol-2-yl)methyl]ether (DGB) or EDGB, L² = 2,2-bipyridine (bipy) or 1,10-phenanthroline (phen)] have been synthesized and characterized by elemental analyses and i.r. spectra. The single-crystal structure of the [Cu(phen)(DGB)(OClO₃)]ClO₄·Et₂O·0.5H₂O complex was determined by X-ray diffraction. The geometry around Cu is best described as a distorted octahedron with four nitrogen atoms from phen and DGB ligands forming the equatorial plane. The oxygen atoms of DGB and one perchlorate group are in the axial positions with semi-coordinated bonding modes. The electrochemical behavior of the complexes is described.     

Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand

Varying coordination modes of the Schiff base ligand H₂L [5-methyl-1-H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H₂L)(H₂O)₂](ClO₄)₂(MeOH) (1), [Co(H₂L)(NCS)₂] (2), [Cd(H₂L)(H₂O)₂](ClO₄)₂ (3) and [Zn(H₂L)(H₂O)₂](ClO₄)₂ (4), and a binuclear Cu(II) complex, [Cu₂(L)₂](ClO₄)₂ (5). In the complexes 1-4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1-4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry (τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent.     

Crystal structure of copper(II) cimetidine sulphate nonahydrate. Cation distortion and structure isomerism in three copper(II) cimetidine complexes

In the crystalline state, the complex [Cu(CM)₂]SO₄·9H₂O (CM = cimetidine) is constituted of two-dimensional cations[Cu(CM)₂²⁺]_n separated by SO₄²⁻ anions and water molecules. As in the related complexes [Cu(CM)₂](ClO₄)₂ and [Cu(CM)₂](NO₃)₂, the copper atom lies in a strongly distorted octahedral CuN₄S₂ environment. The distortion is quite different from one complex to another (cation distortion isomerism). In the title compound the CuS bond is unusually long (2.91 Å). Unlike the title compound, the [Cu(CM)₂²⁺]_n cations in the perchlorate and nitrate salts are one-dimensional infinite chains characterized by different conformations of the cimetidine molecules (cation structure isomerism).     

(1,3‐Dimethylimidazolidine‐2‐selone‐κSe)bis(1,10‐phenanthroline‐κ2N,N′)copper(II) bis(perchlorate) and bis(2,2′‐bipyridyl‐κ2N,N′)(imidazolidine‐2‐thione‐κS)copper(II) bis(perchlorate)

In the first title salt, [Cu(C₁₂H₈N₂)₂(C₅H₁₀N₂Se)](ClO₄)₂, the Cu^II centre occupies a distorted trigonal–bipyramidal environment defined by four N donors from two 1,10‐phenanthroline (phen) ligands and by the Se donor of a 1,3‐dimethylimidazolidine‐2‐selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu—N distances span the range 1.980 (10)–2.114 (11) Å and the Cu—Se distance is 2.491 (3) Å. Intermolecular π–π contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C₁₀H₈N₂)₂(C₃H₆N₂S)](ClO₄)₂, the Cu^II centre occupies a similar distorted trigonal–bipyramidal environment comprising four N donors from two 2,2′‐bipyridyl (bipy) ligands and an S donor from an imidazolidine‐2‐thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu—N distances span the range 1.984 (6)–2.069 (7) Å and the Cu—S distance is 2.366 (3) Å. Intermolecular π–π contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N—H...O hydrogen bonds linking the imidazolidine N—H hydrogen‐bond donors to perchlorate O‐atom acceptors.     

Di‐μ‐hydroxido‐bis{[bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine‐κ3N′,N′′,N′′′]copper(II)} bis(perchlorate)

The title compund, [Cu₂(OH)₂(C₂₂H₂₅N₃)₂](ClO₄)₂, is a copper(II) dimer, with two [CuL]²⁺ units [L is bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine] bridged by hydroxide groups to define the {[CuL](μ‐OH)₂[CuL]}²⁺ cation. Charge balance is provided by perchlorate counter‐anions. The cation has a crystallographic inversion centre halfway between the Cu^II ions, which are separated by 3.0161 (8) Å. The central core of the cation is an almost regular Cu₂O₂ parallelogram of sides 1.931 (2) and 1.935 (2) Å, with a Cu—O—Cu angle of 102.55 (11)°. The coordination geometry around each Cu^II centre can be best described as a square‐based pyramid, with three N atoms from L ligands and two hydroxide O atoms completing the coordination environment. Each cationic unit is hydrogen bonded to two perchlorate anions by means of hydroxide–perchlorate O—H...O interactions.     

Preparation,crystal structures and spectroscopic characterization of oxalate copper(II) complexes containing the nitrogen ligands 4,4′-dimethyl-2,2′-bipyridine and di(2-pyridyl)sulfide

The preparation, crystal structures and spectroscopic characterization of four oxalate copper(II) complexes containing the 4,4′-dimethyl-2,2′-bipyridine (Mebpy) or di(2-pyridyl)sulfide (DPS) nitrogen ligands namely [μ-(ox){Cu(Mebpy)(NO₃)(H₂O)}₂] (1), [μ-(ox){Cu(Mebpy)(ClO₄)(H₂O)}₂] (2), [μ-(ox){Cu(DPS)(H₂O)}₂](ClO₄)₂ (3) and [Cu(DPS)(ox)(H₂O)] · 2H₂O (4) are described. X-ray diffraction measurements have shown that complexes 1–3 are binuclear, in which the oxalate anion bridges two Cu(II) centers, while the complex (4) is mononuclear and the oxalate anion adopts the terminal bidentate chelating coordination mode. In 1 and 2 the Cu(II) sites display a distorted octahedral geometry (4+2 environment) and in compounds 3 and 4 the Cu(II) centers exhibit a slightly distorted square pyramidal geometry. In addition, complexes 1 and 2 present a 2D supramolecular arrangement through hydrogen bonds between coordination water molecules and nitrate or perchlorate anions and π-stacking interaction between the pyridyl rings of Mebpy nitrogen ligands.     

Synthesis of copper(II) and nickel(II) triazacycloalkane complexes

Summary Copper(II) and nickel(II) complexes of triazacycloalkanes (pqr-cy), with p, q, r = 2–6, have been prepared and characterized by means of electronic and i.r. spectroscopy, and by magnetic measurements. With nickel(II) mononuclear octahedral complexes [Ni(pgr-cy)₂](CI0₄)₂ are formed, but for copper(II) mononuclear octahedral complexes were obtained only for 222-cy and 223-cy. The other ligands gave copper(II) complexes of the type [Cu(pgr-cy)CI]CIO₄, [Cu(pgr-cy)OH]ClO₄, Or [Cu(pgr-cy)CI_1/2OH_1/2]ClO₄. The hydroxy complexes have low magnetic moments and binuclear hydroxy bridged structures are proposed.Ligand names: e.g. p = q = r = 2 is 1,4,7-triazacvclononane     

Co(II), Cu(II) and Zn(II) dinuclear complexes of a polypodal ligand containing phenolate and pyridyl donor groups

Acetate and perchlorate dinuclear metal complexes of Co(II), Cu(II) and Zn(II) with the cresolate polypodal ligand having mixed phenolate and pyridyl pendant functionalities, H₃L, have been synthesized. The complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV–Vis spectroscopy, magnetic studies and conductivity measurements. Crystal structures of H₃L, [Cu₂(HL)(OAc)(H₂O)₂](OAc)·1.5H₂O and [Zn₂L(CH₃OH)₃](ClO₄)CH₃OH·2H₂O complexes, have been also determined.     

Coordination behavior of 3,4-bis(2-pyridylmethylthio)toluene with copper(II) ions: Synthesis,structural characterization and reactivity,and DNA binding study of the dinuclear copper(II) complex

On reaction of different copper(II) salts with 3,4-bis(2-pyridylmethylthio)toluene (L) having neutral tetradentate NSSN donor set in different chemical environments, two mononuclear copper(II), one dinuclear copper(I) and one dinuclear copper(II) complexes, formulated as [Cu^II(L)(H₂O)₂](NO₃)₂ (1), [Cu^II(pic)₂] (2), [Cu^I₂(L)₂](ClO₄)₂ (3) and [Cu^II₂(L)₂Cl₂](ClO₄)₂ (4), respectively, were isolated in pure form [where pic = picolinate]. All the complexes were characterized by physicochemical and spectroscopic methods. The product of the reactions are dependent on the counter anion of copper(II) salts used as reactant and on the reaction medium. Complexes 1 and 4 were obtained with nitrate and perchlorate copper(II) salts, respectively. On the other hand, C–S bond cleavage was observed in the reaction of L with copper(II) chloride to form in situ picolinic acid and complex 2. Dinuclear complexes 3 and 4 were separated out when copper(II) perchlorate was allowed to react with L in methanol and in acetonitrile, respectively, under aerobic condition. The X-ray diffraction analysis of the dinuclear complex 3 shows a highly distorted tetrahedral geometry about each copper ion. Complex 4 is converted to 3 in acetonitrile in presence of catechol. The spectral study of complex 4 with calf thymus DNA is indicative of a groove binding mode interaction.