SYNTHESIS AND CRYSTAL STRUCTURE OF A BINUCLEAR COPPER (II) COMPLEX BRIDGED BY OXAMIDATO,Cu2(μ-CIS-OXPN)(PHEN)(NO3)2

Abstract

The complex [Cu₂(μ-cis-oxpn)(phen)(NO₃)₂], where oxpn = N,N′ -bis(3-aminopropyl) oxamidato and phen = 1,10-phenanthroline, has been synthesized and its crystal structure determined by X-ray methods. The structure consists of binuclear copper (II) molecules in which the Cu(II) atoms are bridged by oxamidato group in the cis conformation, the Cu—Cu distance being 5.205(10) Å. The coordination geometry around Cu (II) atoms is square pyramidal; the apex is occupied by a more weakly bonded O atom from a nitrate group. Electron delocalization is observed in the bridging oxamide moiety. The co-planarity of bridge ligand and basal plane around Cu (II) atoms may benefit spin super-exchange between two Cu (II) atoms. IR spectra of the binuclear complex are discussed.     

A Structural Study of the Iminodiacetate Moiety Conformation in N‐(1‐adamantyl)‐iminodiacetate(2‐) Copper(II) Complexes

N,N‐bis(carboxymethyl)‐1‐adamantylamine acid (H₂BCAA) or N‐(1‐adamantyl)‐iminodiacetic acid forms zwitterions that are intra‐stabilized by a ‘bifurcated’ N⁺‐H···O(carboxyl)₂ interaction. In the crystal, both half‐protonated carboxyl groups of H₂BCAA^± are involved in linear O‐H···O inter‐molecular bridges of 2.46Å. In the studied BCAA‐Cu^II derivatives, the iminodiacetate‐moiety of the BCAA chelating ligand exhibits a mer‐NO₂ conformation in [Cu(BCAA)(H₂O)₂] ( 1 ) and [Cu(BCAA)(Him)]₂ ( 2 ), but a fac‐O₂+N(apical) conformation in [Cu(BCAA)(bpy)(H₂O)]·3.5H₂O ( 3 ) [Him = imidazole, bpy =2,2′‐bipyridine]. In clear contrast, dipyridylamine (dpya), as auxiliary ligand, seems to be unable to promote the fac‐O₂+N(apical) conformation in BCAA, as reveal the structures of two new salts with the trinuclear cation [(dpya)₂Cu‐μ₂‐Cu(BCAA)₂‐Cu(dpya)₂]²⁺ and the anions [Cu(BCAA)₂]^2? ( 4 ) or NO₃^? ( 5 ), respectively.     

Syntheses and crystal structure of binuclear μ-oxamido copper(II) complexes containing 1,4,7-triazacyclononane as a terminal ligand

Two new binuclear copper(II) complexes, Cu(tacn)Cu(oxpn)(ClO₄)₂·C₂H₅OH (1), and Cu(tacn)Cu(oxap)(ClO₄)₂·CH₃OH (2), have been prepared from the planar fragment Cu(oxpn) and Cu(oxap) (tacn denotes 1,4,7-triazacyclononane, oxpn and oxap stand for the dianions of N,N′-bis(3-aminopropyl)oxamide, and N,N′-bis(2-aminopropyl)oxamide, respectively). The complexes have been characterized by means of elemental analyses and IR, and UV spectra. The crystal structure of compound 1 shows that copper(II) coordinates to the four nitrogen atoms of oxpn in a square-planar environment and the other copper(II) ion is in a distorted square-pyramidal environment.     

One‐dimensional copper(II) coordination polymers based on 1,3‐bis(pyridin‐4‐yl)propane and diimine ligands

Two one‐dimensional (1D) coordination polymers (CPs), namely catena‐poly[[[aqua(2,2′‐bipyridine‐κ²N,N′)(nitrato‐κO)copper(II)]‐μ‐1,3‐bis(pyridin‐4‐yl)propane‐κ²N:N′] nitrate], {[Cu(NO₃)(C₁₀H₈N₂)(C₁₃H₁₄N₂)(H₂O)]·NO₃}_n ( 1 ), and catena‐poly[[[aqua(nitrato‐κO)(1,10‐phenanthroline‐κ²N,N′)copper(II)]‐μ‐1,3‐bis(pyridin‐4‐yl)propane‐κ²N:N′] nitrate], {[Cu(NO₃)(C₁₂H₈N₂)(C₁₃H₁₄N₂)(H₂O)]·NO₃}_n ( 2 ), have been synthesized using [Cu(NO₃)(NN)(H₂O)₂]NO₃, where NN = 2,2′‐bipyridine (bpy) or 1,10‐phenanthroline (phen), as a linker in a 1:1 molar ratio. The CPs were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray structure determination. The 1,3‐bis(pyridin‐4‐yl)propane (dpp) ligand acts as a bridging ligand, leading to the formation of a 1D polymer. The octahedral coordination sphere around copper consists of two N atoms from bpy for 1 or phen for 2 , two N atoms from dpp, one O atom from water and one O atom from a coordinated nitrate anion. Each structure contains two crystallographically independent chains in the asymmetric unit and the chains are linked via hydrogen bonds into a three‐dimensional network.     

Synthesis,structure and spectral studies on mixed ligand copper(II) complexes of diimines and acetylacetonate

Two new mixed ligand complexes of copper(II) with acetylacetonate (acac), 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) belonging to the class of cytotoxic and antineoplastic compounds known as CASIOPEINAS^® were synthesized and structurally characterized. Crystals of both complexes [Cu(acac)(bpy)(H₂O)]NO₃ · H₂O (1), [Cu(acac)(phen)Br] (2) contain square pyramidal Cu(II) complex species. In frozen solution both compounds give well resolved EPR spectra with very similar parameters.     

Two novel oxamido-bridge dinuclear copper(II) complexes containing four spin carriers involving the nitroxide radical ligand: synthesis,crystal structure and magnetic properties

The combined use of nitroxide free radicals as terminal ligands and precursor [Cu₂(oxpn)]²⁺ anions has led to the preparation of two novel oxamido-bridged dinuclear copper(II) complexes containing nitronyl nitroxide Cu₂(oxpn)(NIToBA)₂ (1) or imino nitroxide [Cu₂(oxpn)(IM_pPy)₂](ClO₄)₂ · 2H₂O (2). X-ray crystallography shows that both (1) and (2) have like as coordination modes where the oxamido group as a trans-form bridged ligand, combine two copper(II) atoms. Each copper (II) ion has a similar coordination environment, in which it adopts a distorted square planar geometry. The temperature dependence of the magnetic susceptibility measurements shows the weak antiferromagnetic co upling interaction between the copper(II) atoms and the nitronyl nitroxide radicals in both complexes.     

Metal complexes with N-(trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands). Part I. Copper(II) chelates of p-3F,m-3F,and o-3F with or without imidazole-like ligands

Eight Cu(II) complexes with N-(p-, m- or o-trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands) have been synthesized to promote C–F/H interligand interactions involving the F₃C-group: {[Cu(μ₂-p-3F)(H₂O)]·3H₂O]}_n (1), [Cu(m-3F)(H₂O)₂] (2), [Cu(p-3F)(Him)(H₂O)] (3), [Cu(m-3F)(Him)(H₂O)] (4), [Cu(o-3F)(Him)(H₂O)] (5), [Cu₂(p-3F)₂(H5Meim)₂(H₂O)₂] (6), [Cu(m-3F)(H5Meim)(H₂O)] (7), and [Cu(o-3F)(H5Meim)(H₂O)] (8) [Him and H5Meim = imidazole and the “remote” tautomer 5-methylimidazole, respectively]. The compounds were studied by single-crystal X-ray diffraction, FT-IR, electronic spectra and coupled thermogravimetric + FT-IR methods. The conformation of the iminodiacetate chelating moiety (IDA group) is fac-NO + O(apical) in 1 and mer-NO₂ in 2–8. The fac-IDA conformation observed in 1 is related to its polymeric structure and the coordination of a O’-carboxylate donor, from an adjacent complex unit, trans to the Cu–N(IDA) bond. The mer-IDA conformation in 2 is in agreement with similar compounds with an aqua ligand trans to the corresponding Cu–N(IDA) bond. As expected, the ternary complexes 3–8 feature a mer-IDA conformation. Some of the studied complexes exhibit disorder in the –CF₃ group and C–H?F interligand interactions along with conventional N–H?O and O–H?O interactions. The thermal decomposition of all studied compounds under air flow produces variable amounts of trifluorotoluene.     

Three new binuclear copper(II) complexes with isonicotinic acid N-oxide: syntheses,crystal structures and properties

Three new copper(II) complexes with isonicotinic acid N-oxide (HL) and 1,10-phenanthroline (phen) as ligands, [Cu(L)(phen)(H₂O)]₂(NO₃)₂···2H₂O (1), [Cu(L)(phen)(H₂O)]₂(ClO₄)₂···2H₂O (2), and [Cu(L)(phen)Br]₂- [Cu(L)(phen)(H₂O)]₂Br₂···6H₂O (3) have been synthesized and structurally characterized. The structures of all three complexes feature a Cu₂ dimer formed by two Cu(II) ions interconnected by two bridging ligands. Each copper(II) ion has a distorted square pyramidal coordination geometry with elongated axial coordination by an aqua ligand or halogen anion. The isonicotinic acid N-oxide anion is bidentate, being coordinated to two Cu(II) ions through its N-O oxygen and one of its carboxylate oxygen atoms. Magnetic susceptibility measurements show a Curie–Weiss paramagnetic behavior characteristic of one unpaired electron for a copper(II) ion for all three complexes.     

Synthesis and application of a new copper(II) complex containing oflx and leof

Two new copper(II) complexes of [Cu(Ofloxacin)(phen)(H₂O)] · (NO₃) · 2H₂O and [Cu(Levofloxacin)(phen)(H₂O)] · (NO₃) · 2H₂O were obtained and their structures were studies. Both ligands and complexes were assayed against gram-positive and gram-negative bacteria by the in vitro doubling dilutions method. The inhibitory effect of the ligands and complexes on the leukemia HL-60 cell line were measured with the MTT assay method and the liver cancer HePG-2 cell line measured by the SRB method. The results indicated that the complexes have stronger inhibitory effect on HL-60 than on HePG-2. The complex [Cu(Levofloxacin)(phen)(H₂O)] · (NO₃) · 2H₂O (I) has stronger effect on HL-60 than the complex (Cu(Ofloxacin)(phen)(H₂O)] · (NO₃) · 2H₂O (II). The text was submitted by the authors in English.     

Synthesis,structure, and DNA-binding studies of a dicopper(II) complex with N-phenolato-N′-[2-(dimethylamino) ethyl]oxamide as ligand

A new µ-oxamido-bridged dicopper(II) complex, [Cu₂(pdmaeox)(bpy)(H₂O)](pic)?·?H₂O [H₃pdmaeox?=?N-phenolato-N′-[2-(dimethylamino)ethyl]oxamide, Hpic?=?2,4,6-trinitrophenol, bpy?=?2,2′-bipyridine], has been synthesized and characterized by elemental analyses, molar conductivity measurement, infrared, and electronic spectra studies, and X-ray single-crystal diffraction. The complex crystallizes in the triclinic system, P 1 space group, with crystallographic data: a?=?10.7815(2)?Å, b?=?11.3598(2)?Å, c?=?14.1389(3)?Å, and z?=?2. In [Cu₂(pdmaeox)(bpy)(H₂O)]⁺, one copper(II) resides in the inner site with a square-planar coordination geometry and the other is chelated by the two exo-oxygen atoms of the cis-pdmaeox^3? ligand in a square-pyramidal environment. The Cu···Cu separation through cis-pdmaeox^3? bridge is 5.1834(4)?Å. The crystal structure is stabilized by hydrogen bonds and π–π stacking interactions. The interaction of the dicopper(II) complex with herring sperm-DNA (HS-DNA) has been investigated by electronic absorption titration, fluorescence titration, electrochemical titration, and viscosity measurements. The results reveal that the interaction of the dicopper(II) complex with HS-DNA might be electrostatic binding. The effects of bridging ligand on the interaction of the dinuclear complex with HS-DNA were preliminarily investigated.     

Assembling of copper(II) dipicolinate complexes

The role of ancillary ligands, namely imidazole (im), pyridine (py), 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) in the assembly of copper(II) dipicolinate complexes are presented. Mononuclear complexes are observed in the case of monodentate ligands. The mononuclear complex [Cu(im)₃L]·4H₂O (1) (L = dipicolinate anion) has a distorted octahedral structure with Z′ = 2, whereas [CuL(py)(H₂O)]·2H₂O (2) adopts distorted square pyramidal geometry. The bidentate ligands bpy and phen favor the formation of dinuclear complexes. The dinuclear complex [CuL(bpy)(μ-L)Cu(bpy)(H₂O)]·9H₂O (3) has one carbonyl oxygen atom of a carboxylate group of dipicolinate acting as a bridging ligand to the copper site that is devoid of a coordinated water molecule. The complex has an angle of 83.55° between the plane of L and bpy attached to one copper site, whereas it has an angle of 78.13° between the plane L and bpy attached to the other copper site. A 1,10-phenanthroline containing dinuclear copper(II) dipicolinate complex, [Cu(phen)(H₂O)(μ-L)Cu(phen)₂][CuL₂]·12H₂O (4), has been structurally characterized. It has an unusual carboxylate bridge.     

Synthesis,Characterization and Magnetic Studies of μ‐Oxamido Copper (II) ‐ Chromium (III) Heterodinuclear Complexes

Three new μ‐oxamido‐bridged heterodinuclear copper (II)‐chromium (III) complexes formulated [Cu(Me₂oxpn)Cr‐(L)₂](NO₃)₃, where Me₂oxpn denotes N,N'‐bis(3‐amino‐2, 2‐dimethylpropyl)oxamido dianion and L represents 5‐methyl‐1,10‐phenanthroline (Mephen), 4,7‐diphenyl‐1,10‐phenanthroline (Ph₂phen) or 2,2′‐bipyridine (bpy), have been synthesized and characterized by elemental analyses, IR and electronic spectral studies, magnetic moments of room‐temperature and molar conductivity measurements. It is proposed that these complexes have oxamido‐bridged structures consisting of planar copper (II) and octahedral chromium (III) ions. The variable temperature magnetic susceptibilities (4.2–300 K) of complexes [Cu(Me₂oxpn)Cr(Ph₂phen)₂](NO₃)₃ (1) and [Cu(Me₂oxpn)Cr(Mephen)₂] (NO₃)₃ (2) were further measured and studied, demonstrating the ferromagnetic interaction between the adjacent chromium (III) and copper (II) ions through the oxamido‐bridge in both complexes 1 and 2. Based on the spin Hamiltonian, ? = ‐ 2J?₁ · ?₂, the exchange integrals J were evaluated as + 21.5 an^?1 for 1 and + 22.8 cm^?1 for 2.     

OBSERVATIONS ON THE CONFORMATION OF IMINODIACETATE(2-) ION IN MIXED LIGAND COPPER(II) COMPLEXES WITH NITROGEN HETEROCYCLES AS SECONDARY LIGANDS. CRYSTAL STRUCTURE OF (2,2′-BYPIRIDINE)(IMINODIACETATO)COPPER(II) HEXAHYDRATE

Abstract

(2,2′-Bipyridine)(iminodiacetato)copper(II) hexahydrate, [Cu(IDA)(2,2′-bipy)]·6H₂O, has been obtained and studied by X-ray diffraction. The compound (triclinic system, space group P1, Z = 2; R = 0.036 and R = 0.040 for 7541 independent reflections) consists of asymmetric dinuclear entities, [Cu(IDA)(2,2′-bipy)]₂, and uncoordinated H₂O molecules in a hydrogen bonding network. Both Cu(II) atoms of each dinuclear entity are chemically very similar. Each Cu(II) atom exhibits a flattened, square pyramidal coordination. Two N atoms of 2,2′-bipy and the N and one O atoms of IDA are at the square base; another O atom of the same terdentate IDA is at the apical position. Two weak interactions between each Cu(II) atom and one O atom from IDA which chelates the second contribute to the dinuclear entity. On the basis of these results and the known structure of other Cu(II) complexes with IDA and imidazole or 4,4′-bipy, an attempt to rationalize the nearly coplanar or perpendicular conformation of the two five-membered IDA-Cu(II) chelate rings in such mixed-ligand copper(II) complexes is made.     

Synthesis and magnetism of 6-nitrobenzimidazolate and imidazolate-bridged copper(II) complexes

Summary Four new trinuclear copper(II) complexes, [Cu(phen)-(NBzIm)] (ClO₄) (1), [Cu(bpy)(NBzIm)](ClO₄) (2), [Cu-(Me₂-bpy)(NBzIm)](Ac)·1/2H₂O (3) and [Cu(Me₂-bpy)-(Im)](ClO₄)·1/2H₂O (4) (phen = 1, 10-phenanthroline, bpy = 2,2-bipyridine, NBzIm = 6-nitrobenzimidazolate ion, Im=imidazolate ion) have been prepared and characterized by variable temperature magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction operates between copper(II) ions, exchange integrals evaluated as J =-23.82 cm^-1 for (1); and J=-21.91 cm^-1 for (2).     

Synthesis,characterization and biological activity of triaminoxime and its metal complexes

Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of multifunctional triaminoxime have been synthesized and characterized by elemental analyses, IR, UV–Vis spectra, magnetic moments, ¹H- and ¹³C-NMR spectra for ligand and its Ni(II) complex, mass spectra, molar conductances, thermal analyses (DTA, DTG and TG) and ESR measurements. The IR spectral data show that the ligand is bi-basic or tri-basic tetradentate towards the metals. Molar conductances in DMF indicate that the complexes are non-electrolytes. The ESR spectra of solid copper(II) complexes [(HL)(Cu)₂(Cl)₂] · 2H₂O (2) and [(L)(Cu)₃(OH)₃(H₂O)₆] · 7H₂O (6) show axial symmetry of a d _{x²???y ²} ground state; however, [(HL)(Co)] (4) shows an axial type with d _Z ² ground state and manganese(II) complex [(L)(Mn)₃(OH)₃(H₂O)6] · 4H₂O (10) shows an isotropic type. The biological activity of the ligand and its metal complexes are discussed.     

THE POLYMERIC COPPER COMPLEX 2,2′-BIPYRIDINE-N,N′-(μ-MALEATO-O,O′:O″)COPPER(II) DIHYDRATE

Abstract

Preparation and isolation of the polynuclear copper(II) complex, {[Cu(bipy)(maleato)] · 2H₂O} _n , was accomplished by reaction of an aqueous solution containing sodium maleate and an ethanolic solution of Cu(NO₃)₂·4H₂O and bipy. The crystal structure of the title complex was determined by single-crystal X-ray methods. The structure consists of one-dimensional infinite chains. The copper atom is five-coordinate and presents a square-pyramidal coordination sphere, which consists of the two imine N atoms of bipy and two terminal carboxylate O atoms of a maleate^2- ligand in the basal plane with Cu-N bond distances of 2.016(3) and 1.987(3) A and Cu-O distances of 1.909(2) and 1.947(2) Å, respectively. In the apical site an O atom of the maleate^2- ligand from an adjacent complex coordinates to copper (2.264(2) Å). The coordination fashion of the maleato ligand is also confirmed by the IR spectrum.     

New structures in the bi­pyridine–copper(II) nitrate–methanol system: [(bpy)2Cu(NO3)]NO3·CH3OH and [(bpy)2Cu(NO3)]NO3

Reaction of 2,2′‐bi­pyridine (bpy) and copper(II) nitrate in methanol results in two complexes, namely light‐blue bis(2,2′‐bi­pyridine)­nitrato­copper(II) nitrate methanol solvate, [Cu(NO₃)(C₁₀H₈N₂)₂]NO₃·CH₃OH, (I), which is unstable in air, and the product of its decomposition, catena‐poly­[[[bis(2,2′‐bi­pyridine)copper(II)]‐μ‐nitrato‐O:O′] nitrate], {[Cu(NO₃)(C₁₀H₈N₂)₂]NO₃}_n, (II). The crystal structures of both compounds were determined from one crystal at room temperature. Later, the structure of (I) was redetermined at low temperature. In (I) and (II), the Cu atom is coordinated by two bpy and one or two nitrate ions, respectively. The second nitrate ion in (I), along with the methanol solvent mol­ecule, is found in the outer coordination sphere, not bonded to Cu. The nitrate in (I) is chelating, while in (II), it bridges (bpy)₂Cu complexes, forming a one‐dimensional chain structure. The Cu cation in (II) lies on a twofold axis and the uncoordinated NO₃^? ion is located close to a twofold axis and is therefore disordered. Compound (I) converts into (II) upon loss of solvent.     

Ternary copper(II) complex of 1,10-phenanthroline and L-glycine: crystal structure and interaction with DNA

A ternary copper(II) complex, [Cu(phen)(L-Gly)(H₂O)] ·?NO₃ ·?1.5H₂O (phen =?1,10-phenanthroline, L-Gly =?L-glycine), has been synthesized and structurally characterized. The complex crystallized in a monoclinic system with space group C2/c, a =?20.572(3) Å, b =?6.9987(10) Å, c =?23.561(3) Å, β?= 98.776(5)°. The five-coordinate copper(II) center is a distorted square pyramid. Absorption spectra, fluorescence spectra and viscosity measurements showed interaction between the copper complex and DNA through an intercalative mode. The complex exhibited efficient DNA cleavage activity at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species.     

Two 2-D copper(II) azido compounds: catena -poly[ di -μ1,1- azido,di -μN,O-(quinolinecarboxylato)(aqua)copper(II)] and 1-D catena -poly[ di -μN,N′-(quinoxaline)copper(II)nitrate]

We synthesized three copper(II) complexes with two structurally related polydentate ligands, quinoline-4-carboxylic acid (quCOOH) and quinoxaline (qux). The structures of these complexes were determined using X-ray single crystal crystallography. Complex 1, [Cu(quCOO)(N₃)(H₂O)] _n , has a 2-D polymeric structure through di-μ_1,1 azido groups forming (Cu₂N₂) dimeric units and di-μ_N,O quinoline carboxylate bridging the binuclear copper units. [Cu(quCOO)(N₃)(H₂O)] _n · 0.87MeOH, (2), has the same structure as 1 in addition to MeOH molecules separating the 2-D sheets of [Cu(quCOO)(N₃)(H₂O)] _n . [Cu(qux)(NO₃)₂] _n , (3), has no coordinated azido groups, but the quinoxaline is a bidentate bridging ligand giving a 1-D chain, while the μ_O,O′ chelating nitrato groups stabilize the chain structure by forming a square planar coordination sphere around copper. IR and UV–Vis spectra of the complexes are in agreement with the crystal structures.     

Synthesis,crystal structure and magnetic properties of [(LCu)(MeOH)Cu(phen)-(MeOH)]ClO4·NO3 (H2L = 2,3-dioxo-5,6:15,16-dibenzo-1,4,8,13-tetraazacyclo-pentadeca-7,13-diene)

A dinuclear copper(II) [(LCu)(MeOH)Cu(phen)(MeOH)]ClO₄·NO₃ macrocyclic complex (where H₂L = 2,3-dioxo-5,6:15,16-dibenzo-1,4,8,13-tetraazacyclo-pentadeca-7,13-diene; phen = 1,10-phenanthroline) has been synthesized and characterized by means of elemental analysis and its i.r. spectrum. Its crystal structure has been determined by single-crystal X-ray diffraction. In the complex, both the copper ions are penta-coordinated and have a distorted square pyramid configuration. Magnetic susceptibility measurements show antiferromagnetic exchange interactions (J = –207.64 cm^–1) between the copper(II) ions.