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.     

Two‐dimensional square‐grid frameworks formed by self‐associating copper(II) complexes with 1‐(3‐pyridyl)‐ and 1‐(4‐pyridyl)‐substituted butane‐1,3‐diones

In bis­[1‐(3‐pyridyl)butane‐1,3‐dionato]copper(II) (the Cu atom occupies a centre of inversion), [Cu(C₉H₈NO₂)₂], (I), and bis­[1‐(4‐pyridyl)butane‐1,3‐dionato]copper(II) methanol solvate, [Cu(C₉H₈NO₂)₂]·CH₃OH, (II), the O,O′‐chelating diketonate ligands support square‐planar coordination of the metal ions [Cu—O = 1.948 (1)–1.965 (1) Å]. Weaker Cu⋯N inter­actions [2.405 (2)–2.499 (2) Å], at both axial sides, occur between symmetry‐related bis­(1‐pyridylbutane‐1,3‐dion­ato)copper(II) mol­ecules. This causes their self‐organization into two‐dimensional square‐grid frameworks, with uniform [6.48 Å for (I)] or alternating [4.72 and 6.66 Å for (II)] inter­layer separations. Guest methanol mol­ecules in (II) reside between the distal layers and form weak hydrogen bonds to coordinated O atoms [O⋯O = 3.018 (4) Å].     

A mixed bridged trinuclear copper(II)–1,10‐phenanthroline complex with a linear structure

The title compound, diaqua‐1κO,3κO‐di‐μ‐hydroxido‐1:2κ²O:O,2:3κ²O:O‐di‐μ‐methacrylato‐1:2κ²O:O′,2:3κ²O:O′‐bis(1,10‐phenanthroline)‐1κ²N,N′;3κ²N,N′‐tricopper(II) dinitrate dihydrate, [Cu₃(C₄H₅O₂)₂(OH)₂(C₁₂H₈N₂)₂(H₂O)₂](NO₃)₂·2H₂O, has the central Cu atom on an inversion centre. The three Cu^II atoms are in a linear arrangement linked by methacrylate and hydroxide groups. The coordination environments of the Cu^II ions are five‐coordinated distorted square‐pyramidal for the outer Cu atoms and four‐coordinated square‐planar for the central Cu atom. All nitrate ions, hydroxide groups and water molecules are linked by hydrogen bonds, forming a linear structure. The complex exhibits ferromagnetic exchange coupling, which is helpful in elucidating magnetic interactions between copper ions and other metallic ions in heteronuclear complexes.     

Poly­[[bis­(pyridine‐κN)copper(II)]‐μ3‐5‐hydroxy­isophthalato‐κ3O:O′:O′′]

In the title compound, [Cu(C₈H₄O₅)(C₅H₅N)₂]_n or [Cu(OH‐BDC)(py)₂]_n (where OH‐H₂BDC is 5‐hydroxy­isophthalic acid and py is pyridine), the Cu atoms are coordinated by two N atoms from the pyridine ligands and by three O atoms from hydroxy­isophthalate ligands in a highly distorted triangular bipyramidal environment, with Cu—O distances in the range 1.941 (4)–2.225 (5) Å and Cu—N distances of 2.014 (6) and 2.046 (6) Å. The [Cu(OH‐BDC)]_n two‐dimensional network is built up from interlocking 22‐, 15‐ and eight‐membered rings via sharing of Cu atoms and O—H⋯O hydrogen bonds. Consolidation of the packing structure is achieved by edge‐ or point‐to‐face C—H⋯π interactions and offset or slipped π–π stacking interactions.     

μ‐3,4′‐Bi‐1,2,4‐triazole‐di‐μ‐chloro‐cuivre(II) monohydraté

In the title compound, μ‐3,4′‐bi‐1,2,4‐triazole‐di‐μ‐chloro‐copper(II) monohydrate, {[CuCl₂(C₄H₄N₆)]·H₂O}_n, the Cu atom is located in a distorted octahedron consisting of two N atoms and four Cl atoms. The structural unit is an infinite chain in which octahedral groups, connected by shared edges, are also linked by bitriazole mol­ecules. The bitriazole ligand, the Cu atom and the water O atom all lie on independent twofold axes. The structure is held together by hydrogen bonds between the water mol­ecules and the non‐coordinated N atoms of the ligand, and by van der Waals forces.     

3‐(4‐Cyano­phenyl)­pentane‐2,4‐dione and its copper(II) complex

The β‐diketone 3‐(4‐cyano­phenyl)­pentane‐2,4‐dione crystallizes as the enol tautomer 4‐(2‐hydroxy‐4‐oxopent‐2‐en‐3‐yl)­benzo­nitrile, C₁₂H₁₁NO₂, (I), with an intramolecular O—H⋯O hydrogen bond [O⋯O = 2.456 (2) Å]. Reaction of (I) with copper acetate monohydrate in the presence of triethyl­amine leads to the formation of the copper(II) complexbis­[3‐(4‐cyano­phenyl)­pentane‐2,4‐dionato‐κ²O,O]copper(II), [Cu(C₁₂H₁₀NO₂)₂], (II). In the structure of (II), the Cu atom is coordinated by four β‐diketonate O atoms in a slightly distorted square‐planar geometry, with Cu—O distances in the range 1.8946 (11)–1.9092 (11) Å. The nitrile moieties in (II) make it a candidate for reaction with other metal ions to produce supramolecular structures.     

SYNTHESIS AND CRYSTAL STRUCTURE OF OXAMIDATO-BRIDGED BINUCLEAR COPPER(II) COMPLEXES

Abstract

The compounds [Cu(oxpn)] (1), [(bpy)(H₂O)Cu(μ-cis-oxpn)Cu(H₂O)] · 2NO₃ · 2H₂O (2) and [(Him)(NO₃)Cu(μ-trans-oxpn)Cu(Him)(NO₃)] (3), where oxpn is the dianion of N,N′-bis(3-aminopropyl)oxamide, bpy is bipyridine and Him is imidazole, were prepared and characterized by elemental analysis and IR spectra. Complex (2) was also studied by thermochemical analysis and its structure determined by X-ray crystallography. The structure of complex (2) consists of binuclear copper(II) molecules in which the copper(II) atoms are bridged by an oxamidato group in the cis conformation resulting a copper-copper distance of 5.21 Å. Both copper(II) ions are in square-pyramidal surroundings with almost coplanar basal planes and a water molecule occupying the apical positions. The N atoms of the oxamidato moiety are trigonal. Two lattice water molecules together with the two coordinated ones hydrogen bond with nitrate ions.     

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and its Complexes with Copper(II) Chloride and Copper(II) Perchlorate

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole (hnt), prepared by alkylation of 3‐nitro‐1, 2, 4‐triazole with 2‐chloroethanol, was found to react with copper(II) chloride and copper(II) perchlorate in acetonitrile/ethanol solutions giving complexes [Cu₂(hnt)₂Cl₄(H₂O)₂] and[Cu(hnt)₂(H₂O)₃](ClO₄)₂, respectively. They are the first examples of coordination compounds with a neutral N‐substituted 3‐nitro‐1, 2, 4‐triazole ligand. 1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and the obtained complexes were characterized by NMR and IR spectroscopy, X‐ray, and thermal analyses. [Cu₂(hnt)₂Cl₄(H₂O)₂] presents a dinuclear chlorido‐bridged complex in which hnt acts as a chelating bidentate ligand, coordinated to the metal by a nitrogen atom of the triazole ring and an oxygen atom of the nitro group, and the copper atoms are inconsiderably distorted octahedral coordination. [Cu(hnt)₂(H₂O)₃](ClO₄)₂comprises a mononuclear complex cation, in which two nitrogen atoms of two hnt ligands in trans configuration and three water oxygen atoms form a square pyramidal environment around the copper atom, which is completed to an distorted octahedron with a bifurcated vertex due to two additional elongated Cu–O bonds with two nitro groups. In both complexes, Cu–O bonds with the nitro groups may be considered as semi‐coordinated.     

Tetra­kis(1‐eth­yl‐1H‐1,2,4‐triazole‐κN4)bis­(nitrato‐κO)copper(II) and bis­(nitrato‐κO)tetra­kis­(1‐prop­yl‐1H‐1,2,4‐triazole‐κN4)copper(II)

The copper(II) environments for tetra­kis­(1‐eth­yl‐1,2,4‐triaz­ole)­dinitratocopper(II), [Cu(NO₃)₂(C₄H₇N₃)₄], and tetrakis­(1‐prop­yl‐1,2,4‐triazole)dinitratocopper(II), [Cu(NO₃)₂(C₅H₉N₃)₄], are distorted square bipyramidal. Both structures are centrosymmetric, with the copper(II) ions located at inversion centers coordinated by four N atoms of four triazole mol­ecules and by two O atoms of two nitrate ions in an elongated octa­hedral geometry. This elongation is a result of the Jahn–Teller effect. The largest distortion is that of the N—Cu—O angles, which differ from 90° by 5.68 (10)° in the eth­yl and 5.59 (8)° in the prop­yl derivative.     

Di‐μ‐hydroxo‐bis{(aceto­nitrile)dibenzyl(6‐methyl‐2‐pyridylmethyl)amine‐κ2N,N]copper(II)} bis(perchlorate)

The title compound corresponds to a copper(II) dimer, [Cu₂(OH)₂(C₂H₃N)₂(C₂₁H₂₂N₂)₂](ClO₄)₂, where the metal centres are μ₂‐bridged by hydroxo groups. The coordination of each copper(II) centre is a slightly distorted square‐based pyramid, with two N atoms from dibenzyl(6‐methyl‐2‐pyridylmethyl)amine (BiBzMePMA) and two hydroxo O atoms occupying the basal positions, and the aceto­nitrile N atom at the apical position. The dimer is centrosymmetric, with a crystallographic inversion centre midway between the two Cu atoms [Cu⋯Cu = 2.9522 (9) Å]     

Di- and trinuclear olato-bridged copper(II) compounds of 3,7-bis(3-olatopropyl)-1,3,5,7-tetraazabicyclo[3,3,1]nonane (protan); the structures of [{Cu(μ-protan)}2Cu](ClO4)2·H2O and [{Cu(μ-protan)}Cu(OH)2](ClO4)2·0.5(EtOH)

A compound with a linear trinuclear copper(II) cation, [Cu₃(μ-protan)₂](ClO₄)₂·H₂O (protanH₂ = 3,7-bis(3-hydroxypropyl)-1,3,5,7-tetraazabicyclo[3,3,1]-nonane) is formed by reaction of copper(II) perchlorate, 3-aminopropanol, ammonia and methanal. The cation is approximately centrosymmetrical with Cu?Cu = 2.9870(5) and 2.9485(5) Å. The terminal copper(II) ions are coordinated by nitrogen atoms 3 and 7 of the tetraazabicycle (Cu–N_mean = 2.021(5) Å) and the two oxygen atoms of the 3,7-bis(3-olatopropyl) substituents (Cu–O_mean = 1.911(3) Å), which also act as bridging groups to the central copper(II) ion (Cu–O_mean = 1.926(4) Å). The cation is both helically twisted (dihedral angle N3?N7?N3′?N7′ = 20(1)°) and bent (angle Cu?Cu?Cu = 171(1)°). The copper(II) ions have tetrahedrally twisted square planar primary coordination, with perchlorate ion oxygen atoms weakly coordinated axially to the two terminal copper(II) ions, on opposite sides of the “plane” of the molecule, while the central copper(II) ion is weakly coordinated axially by a water molecule, with all axial Cu–O distances ca. 2.9 Å. One N·CH₂·CH₂·CH₂·O chelate ring for each protan²⁻ ligand shows conformational disorder and the perchlorate ions show rotational disorder. Partial hydrolysis of the protan²⁻ compound gave a compound [{Cu(μ-protan)}Cu(OH)₂](ClO₄)₂·0.5(EtOH) which has a dinuclear cation, with one copper(II) ion in square-planar coordination by tetradentate protan²⁻ and the other in square-planar coordination by the two bridging oxygen atoms of the protan²⁻ ligand and by two hydroxide ions, with Cu?Cu = 3.045(1) Å. With differing mole ratios of the same reactants compounds of the dinuclear cation [{Cu(μ-pta)}₂]²⁺ (ptaH = 3(3-hydroxypropyl)-1,3,5,7-tetraazabicyclo[3,3,1]nonane) are formed.     

In situ single‐crystal to single‐crystal (SCSC) transformation of the one‐dimensional polymer catena‐poly[[diaqua(sulfato)copper(II)]‐μ2‐glycine] into the two‐dimensional polymer poly[μ2‐glycine‐μ4‐sulfato‐copper(II)]

The one‐dimensional coordination polymer catena‐poly[diaqua(sulfato‐κO)copper(II)]‐μ₂‐glycine‐κ²O:O′], [Cu(SO₄)(C₂H₅NO₂)(H₂O)₂]_n, (I), was synthesized by slow evaporation under vacuum of a saturated aqueous equimolar mixture of copper(II) sulfate and glycine. On heating the same blue crystal of this complex to 435 K in an oven, its aspect changed to a very pale blue and crystal structure analysis indicated that it had transformed into the two‐dimensional coordination polymer poly[(μ₂‐glycine‐κ²O:O′)(μ₄‐sulfato‐κ⁴O:O′:O′′:O′′)copper(II)], [Cu(SO₄)(C₂H₅NO₂)]_n, (II). In (I), the Cu^II cation has a pentacoordinate square‐pyramidal coordination environment. It is coordinated by two water molecules and two O atoms of bridging glycine carboxylate groups in the basal plane, and by a sulfate O atom in the apical position. In complex (II), the Cu^II cation has an octahedral coordination environment. It is coordinated by four sulfate O atoms, one of which bridges two Cu^II cations, and two O atoms of bridging glycine carboxylate groups. In the crystal structure of (I), the one‐dimensional polymers, extending along [001], are linked via N—H...O, O—H...O and bifurcated N—H...O,O hydrogen bonds, forming a three‐dimensional framework. In the crystal structure of (II), the two‐dimensional networks are linked via bifurcated N—H...O,O hydrogen bonds involving the sulfate O atoms, forming a three‐dimensional framework. In the crystal structures of both compounds, there are C—H...O hydrogen bonds present, which reinforce the three‐dimensional frameworks.     

Copper(II) and zinc(II) complexes of pyridine‐2,6‐di­carboxyl­ic acid

The title compounds, bis­(pyridine‐2,6‐di­carboxyl­ato‐N,O,O′)copper(II) monohydrate, [Cu(C₇H₄NO₄)₂]·H₂O, andbis(pyridine‐2,6‐dicarboxylato‐N,O,O′)zinc(II) trihydrate, [Zn(C₇H₄NO₄)₂]·3H₂O, have distorted octahedral geometries about the metal centres. Both metal ions are bonded to four O atoms and two pyridyl‐N atoms from the two terdentate ligand mol­ecules, which are nearly perpendicular to each other. The copper(II) complex has twofold crystallographic symmetry and contains two different ligand mol­ecules, one of which is neutral and another doubly ionized. In contrast, the zinc(II) complex contains two identical singly ionized ligand mol­ecules. Both crystal structures are stabilized by O—H?O intermolecular hydrogen bonds between the complex and the water mol­ecules.     

[N‐(2‐Hydroxy­ethyl)ethyl­enediamine‐κ3N,N′,O]‐cis‐bis(isothio­cyanato‐κN)copper(II)

In the novel transition metal isothio­cyanate complex of N‐(2‐hydroxy­ethyl)ethyl­enediamine (hydet‐en) with copper, [Cu(NCS)₂(C₄H₁₂N₂O)], the Cu atom lies in a distorted square‐pyramidal environment, coordinated by four N atoms in the basal plane and an apical O atom. The hydet‐en ligand is N,N,O‐tridentate, in contrast to the disposition in previously studied complexes, while the isothio­cyanate ions act as N‐atom donor ligands. The monomeric units are linked to one another by hydrogen bonds.     

Synthesis and structural studies of (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}pyridin-2-yl)imino]butan-2-one oxime, ligand and its mono-, di- and trinuclear copper(II) complexes

A new dioxime ligand, (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}-pyridin-2-yl)imino]butan-2-one oxime, (H₂Pymdo) (3) has been synthesized in H₂O by reacting 2,3-butenedione monoxime (2) with 2,6-diaminopyridine. Mono-, di- and tri-nuclear copper(II) complexes of the dioxime ligand (H₂Pymdo) and/or 1,10-phenanthroline have been prepared. The dioxime ligand (H₂Pymdo) and its copper(II) complexes were characterized by ¹H-n.m.r., ¹³C-n.m.r. and elemental analyses, magnetic moments, i.r. and mass spectral studies. The mononuclear copper(II) complex of H₂Pymdo was found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The trinuclear copper(II) complex (6) was formed by coordination of the third Cu(II) ion with dianionic oxygen atoms of each of two molecules of the mononuclear copper(II) complexes. The data support the proposed structure of H₂Pymdo and its Cu(II) complexes.     

catena‐Poly[[aquacopper(II)]‐μ‐hydroxido‐μ‐naphthalene‐1‐carboxylato‐κ2O:O′]: effect of a bulky aromatic skeleton in self‐assembly

In the title coordination polymer, [Cu(C₁₁H₇O₂)(OH)(H₂O)]_n, the Cu^II center is five‐coordinated by two O atoms from two different naphthalene‐1‐carboxylate (L) ligands, one O atom from one coordinated water molecule and two O atoms from two hydroxide anions. L ligands and hydroxide anions jointly bridge adjacent Cu^II centers to generate a one‐dimensional chain along the b‐axis direction. The results reveal that the steric bulk of the naphthalene ring system in L may play an important role in the formation of the title complex.     

A novel copper(II) coordination polymer with 2,2′‐bipyridyl‐3,3′‐di­carboxylic acid

A novel copper(II) coordination polymer, poly­[[[aqua­copper(II)]‐μ₃‐2,2′‐bipyridyl‐3,3′‐di­carboxyl­ato‐κ⁴N,N′:O:O′] dihydrate], {[Cu(C₁₂H₆N₂O₄)(H₂O)]·2H₂O}_n, was obtained by the reaction of CuCl₂·2H₂O and 2,2′‐bipyridyl‐3,3′‐di­carboxylic acid (H₂L) in water. In the mol­ecule, each Cu^II atom is five‐coordinated and lies at the centre of a square‐pyramidal basal plane, bridged by three L ligands to form a two‐dimensional (4,4)‐network. Each L moiety acts as a bridging tetradentate ligand, coordinating to three Cu^II atoms through its two aromatic N atoms and two O atoms of the two carboxyl groups. The two‐dimensional square‐grid sheets superimpose in an off‐set fashion through the inorganic water layer.     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Reactivity of substituted copper(II) salicylates with tert‐butylperoxyl radical: Structure–reactivity relationships

Absolute rate constants (k_eff) for the chemical reactions of Cu(II)₂(3,5‐di‐iso‐propylsalicylate)₄(H₂O)₃, Cu(II)₂(3,5‐di‐tert‐butylsalicylate)₄, Cu(II)₂(3,5‐di‐tert‐butylsalicylate)₄(H₂O)₄, Cu(II)₂(3,5‐dimethylsalicylate)₄(H₂O)₃, Cu(II)₂(3‐ethylsalicylate)₄(H₂O), Cu(II)₂(3‐phenylsalicylate)₄, and Cu(II)(3,5‐di‐iso‐propylsalicylate)₂(pyridine)₂ with tert‐butylperoxyl radical were determined using kinetic electron paramagnetic resonance measurements in 10% toluene in the hexane medium at temperatures ranging from ?63°C to 2°C. These antioxidant (AO) chelates were ranked by their reactivity as follows: 2,6‐di‐tert‐butyl‐4‐methylphenol ? Cu(II)₂(3,5‐di‐tert‐butylsalicylate)₄ ? Cu(II)₂(3‐phenylsalicylate)₄ > Cu(II)₂(3,5‐di‐iso‐propylsalicylate)₄(H₂O)₃ ? Cu(II)₂(3,5‐di‐tert‐butylsalicylate)₄(H₂O)₄ ? Cu(II)₂(3,5‐dimethylsalicylate)₄(H₂O)₃ > Cu(II)₂(3‐ethylsalicylate)₄(H₂O) ? Cu(II)(3,5‐di‐iso‐propylsalicylate)₂(pyridine)₂ at 20°C. Differential pulse voltammetry was used to determine redox behavior of these chelates in CH₂Cl₂. Two types of salicylic OH groups were detected in these Cu(II) salicylates, characterized by the presence or absence of AO reactivity. One of them was coordinate covalently bonded to Cu(II) via the oxygen atoms of the salicylic OH groups, displaying oxidation peak potentials in the range from +650 to 970 mV versus Ag/Ag⁺. The second type was intramolecularly hydrogen bonded to carboxylate oxygens, with an oxidation peak potential in the range from +1100 to 1200 mV versus Ag/Ag⁺. It was concluded that non–hydrogen‐bonded salicylic OH groups are responsible for the antiperoxyl radical reactivity of these chelates, while neither Cu(II) nor salicylate ligands displayed reactivity with peroxyl radical. It has been established in this research that axially bonded electron pair donors such as pyridine and water decrease H‐donating reactivity of Cu(II) salicylates by promoting the formation of intramolecular hydrogen bonding between the salicylic OH hydrogen atoms and carboxylate oxygen atoms in the salicylic ligands. Dependences of log k_eff at 20°C and the anodic oxidation potential (E_pa) for the salicylic OH group on the difference between symmetric and asymmetric stretching frequencies of carboxylate groups (in Fourier transform infrared spectra) for the substituted Cu(II) salicylates were determined. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 56–67, 2010     

Cobalt(II), nickel(II) and copper(II) complexes of iso­quinoline‐3‐carbox­ylate

The crystal structures of the title complexes, namely trans‐bis­(iso­quinoline‐3‐carboxyl­ato‐κ²N,O)­bis­(methanol‐κO)cobalt(II), [Co(C₁₀H₆NO₂)₂(CH₃OH)₂], and the corresponding nickel(II) and copper(II) complexes, [Ni(C₁₀H₆NO₂)₂(CH₃OH)₂] and [Cu(C₁₀H₆NO₂)₂(CH₃OH)₂], are isomorphous and contain metal ions at centres of inversion. The three compounds have the same distorted octahedral coordination geometry, and each metal ion is bonded by two quinoline N atoms, two carboxyl­ate O atoms and two methanol O atoms. Two iso­quinoline‐3‐carboxyl­ate ligands lie in trans positions, forming the equatorial plane, and the two methanol ligands occupy the axial positions. The complex mol­ecules are linked together by O—H⋯O hydrogen bonds between the methanol ligands and neighbouring carboxyl­ate groups.