Copper(II) complexes containing hemilabile tridentate ligand as chromotropic probes

Two copper(II) complexes with the general formula [Cu(L)(H₂O)](ClO₄)₂ (1) and [Cu(L)₂](ClO₄)₂ (2), where L=3-((pyridin-2-ylmethyl)amino)propanamide, were synthesized and characterized by elemental analyses, IR, UV–vis spectroscopy techniques and molar conductance measurements. The crystal structures of the complexes were identified by single crystal X-ray diffraction analysis. The tridentate ligand L acts as an N₂O-donor through the nitrogen atoms of the pyridine and amine moieties as well the oxygen atom of the amide group. The copper(II) ions in both complexes have distorted octahedron structures so that the Cu(II) ion in 1 is coordinated by an aqua ligand and a tridentate ligand defining the basal plane, and by two oxygen atoms of the perchlorate ions occupying the axial positions. However, two ligands L are coordinated to the copper(II) ion in 2, where four nitrogen atoms of pyridine and amine groups occupy the equatorial positions and two oxygen atoms of the amide moieties exist in the apices. The chromotropism (halo-, solvato- and ionochromism) of both complexes were studied using visible absorption spectroscopy. The complexes are soluble in water and organic solvents and display reversible halochromism. The solvatochromism property is due to structural change followed by solvation of the vacant sites of the complexes. The complexes demonstrated obvious ionochromism and are highly sensitive and selective towards CN^? and N₃^? anions in the presence of other halide and pseudo-halide ions.     

Template-directed synthesis of macrocyclic copper(II) complexes of diazacyclam, 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane

Template reaction of copper(II) nitrate with N-(2-aminoethyl)-1,3-diaminopropane and formaldehyde yields a macrocyclic copper(II) complex of 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1^6,10]eicosane (L), [CuL(NO₃)₂] (1). Replacement of nitrate with perchlorate gives [CuL(ClO₄)₂] (2). These complexes have been characterized by FT-IR and Raman spectroscopies, electronic absorption, cyclic voltammetry, and X-ray crystallography. The crystal structure of 1 shows that copper has distorted octahedral geometry with two secondary and two tertiary amines of the macrocycle and two oxygen atoms from nitrate coordinating the axial positions. The copper in 2 has the same geometry with axial positions occupied by one oxygen atom of perchlorate. Copper lies on the plane of four coordinated nitrogen atoms and there is no rms deviation from this plane. Cyclic voltammetry of 1 and 2 gives two one-electron waves corresponding to Cu^II/Cu^III (?0.75,??0.72) and Cu^II/Cu^I (0.48, 0.24) processes. For understanding of geometry parameters in diazacyclam-based copper(II) complexes, a survey on complexes from CSD structures is presented. In this study the macrocycle hole size was estimated by ionic radii of metal ions located inside of it.     

Synthesis,structure and spectroscopic properties of CuL(MeOH), H2L = (E)-N 1-(2-((2-aminocyclohexydiimino)(phenyl)methyl)-4-chlorophenyl)-N 2-(2-benzyl-4-chlorophenyl)oxalamide

A new kind of copper(II) complex, CuL(MeOH) (H₂L?=?(E)-N ¹-(2-((2-aminocyclohexydiimino)(phenyl)methyl)-4-chlorophenyl)-N ²-(2-benzyl-4-chlorophenyl)oxalamide) has been synthesized and its structure determined by single-crystal X-ray methods. Copper(II) ion is five-coordinate, bonding to four nitrogen atoms from H₂L and one oxygen atom from MeOH. Hydrogen bonds in the crystal result in the formation of a one-dimensional structure. EPR spectra are discussed. Computer simulation gave g_||?=?2.200, g_⊥?=?2.002. On the basis of the synthesis and the crystal structure, the mechanism of the metal template reaction involved in the formation of the complex was verified.     

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.     

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.     

Coordination behaviour of Schiff base 2-acetyl-2-thiazoline hydrazone (ATH) towards cobalt(II), nickel(II) and copper(II)

The synthesis and characterization of Co(II), Ni(II) and Cu(II) complexes of 2-acetyl-2-thiazoline hydrazone (ATH) are reported. Elemental analysis, IR spectroscopy, UV–Vis–NIR diffuse reflectance and magnetic susceptibility measurement, as well as, in the case of copper complex EPR spectroscopy, have been used to characterize the complexes. In addition, the structure of [NiCl₂(ATH)₂] (2) and [{CuCl(ATH)}₂(μ-Cl)₂] (3) have been determined by single crystal X-ray diffraction. In all complexes, the ligand ATH bonds to the metal ion through the imine and thiazoline nitrogen atoms. X-ray data indicates that the environment around the nickel atom in 2 may be described as a distorted octahedral geometry with the metallic atom coordinated to two chlorine atoms, two thiazoline nitrogen atoms and two imino nitrogen atoms. With regard to 3, it can be said that its structure consists of dimeric molecules in which copper ions are bridge by two chlorine ligands. The geometry about each copper ion approximates to a distorted square pyramid with each copper atom coordinated to one thiazoline nitrogen atom, one imine nitrogen atom, one terminal chlorine ligand and two bridge chlorine ligands. In compound 3, magnetic susceptibility measurements in the temperature range 2–300 K show an intradimer antiferromagnetic interaction (J = −7.5 cm⁻¹).     

Synthesis of cobalt(II), nickel(II) and copper(II) complexes with 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene and crystal structures of {bis(methanol)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}nickel(II) and {bis(2,2′-bipyridine)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}copper(II)

Electrochemical oxidation of metal anodes (cobalt, copper and nickel) in acetonitrile solutions of 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene (H₂L) gave [CoL], [CuL] and [NiL] complexes. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) was added to the electrolytic cell, the mixed complexes [MLL′] (M=Co, Cu, L′=bipy or M=Ni, L′=phen) were obtained. A binuclear compound of composition [Ni₂L₂(MeOH)₄] (1) was synthesized by reaction of the ligand H₂L and nickel(II) acetate in methanol. X-ray structure determination showed the compound to be binuclear, with each nickel atom coordinated to two nitrogen and two bridging phenol oxygen atoms of two dianionic ligands and two methanol molecules, in an octahedral environment. The crystal structure of [CuLbipy] (2) was determined by X-ray diffraction; with the copper atom in a distorted bipyramidal environment defined by the two bipyridine nitrogen atoms and by the phenolic oxygen and the nitrogen atoms of the dianionic ligand. The electronic and vibrational spectral data of the complexes are discussed and related to the structure.     

The synthesis and structure of a novel 1D copper(II) weak coordination polymer with 2,6-pyridinedicarboxylic acid

A novel copper complex, [Cu(dipic)(H₂O)₂] _n (H₂dipic?=?2,6-pyridinedicarboxylic acid), was synthesized and its crystal structure determined by X-ray diffraction. The complex has a polymeric structure of infinite one-dimensional (1D) zigzag chains, consisting of six-coordinate Cu(II) units. Each copper(II) ion is in a distorted octahedral environment with a CuNO₅ core: two oxygen atoms and one nitrogen atom from one dipic anion, one oxygen atom from an adjacent dipic ligand and two oxygen atoms from coordinated water. Each dipic anion connects two copper ions via a μ₂-oxygen atom. The zigzag 1D-chains are linked by extensive hydrogen bonds to form 2D infinite sheets.     

Synthesis and characterization of mononuclear copper(II) and cadmium(II) complexes with di-(2-picolyl)sulfur

The reaction of Cu(ClO₄)₂·6H₂O and Cd(ClO₄)₂ with di-(2-picolyl)sulfur (dps) leads to the formation of mononuclear complexes [Cu(dps)(H₂O)(ClO₄)](ClO₄) (1) and [Cd(dps)₂](ClO₄)₂ (2). The crystal structure of 1 exhibits a distorted square pyramidal geometry, coordinated by one sulfur and two nitrogen atoms from the dps ligand, one water molecule and one perchlorate oxygen atom. For 2, the environment around cadmium atom is in a distorted octahedron with four nitrogen and two sulfur atoms from the dps ligand. Cyclic voltammetric data show that complexes undergo two waves of a one-electron transfer corresponding to M(II)/M(III) and M(II)/M(I) processes. Spectral and electrochemical behaviors of the complexes are also discussed.     

Synthesis,Crystal Structures and Magnetic Properties of Two Methoxo-Bridged Dimeric Copper(II) Complexes [Cu 2(APMD)4(μ2-OMe) 2 ]X 2(APMD = 2-aminopyrimidine; X = BF4 or CIO4)

Two bis-methoxo-bridged dimeric copper(II) complexes, [Cu₂(OMe)₂(APMD)₄](BF₄)₂ 1 and [Cu₂(OMe)₂(APMD)₄](ClO₄)₂ 2, were prepared and characterized by x-ray single-crystal structure analysis and magnetic susceptibility. Complexes 1 and 2 are isomorphous, being composed of discrete [Cu₂( w 2-OMe)₂(APMD)₄]²⁺ cations and anions with each Cu(II) atom ligated by two pyrimidine nitrogen atoms (Cu-N , 2.01Å) from two APMD ligands and two oxygen atoms (Cu-O , 1.92Å) from the w 2 -methoxo groups in a distorted square-planar geometry. The intramolecular metal-metal separations in the two complexes are ca. 2.95 Å. The intermediate antiferromagnetic exchanges (J , m 270 cm^-1) for the two complexes indicate a good overlap between the electronic orbitals of the square-planar copper(II) center via bridging oxygen atoms.     

Synthesis and Structural Studies of 2-(hydroxyimino)-1-methylpropylideneamino-phenyliminobutan-2-one Oxime, Ligand and its Complexes with Cu(II) and Ni(II)

A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H₂Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H₂Phmdo were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H₂Phmdo were 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) or Ni^(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 data support the proposed structure of H₂Phmdo and its complexes.     

Synthesis of new Cu(II), Ni(II) and Co(II) complexes with a bis-amide ligand functionalized with pyridine moieties: Spectral, magnetic and electrochemical studies

Three new copper(II), nickel(II) and cobalt (II) dinuclear complexes with a bis-amide ligand derived from tartaric acid have been prepared and characterized. For this purpose, the ligand (R,R)-(+)-di-N,N′-methylpyridino-tartramide (dmpt) was synthesized via the classical aminolysis of (R,R)-(+)-dimethyltartrate with pyridylmethylamine. The molecular structures of the complexes Na[Cu₂(dmptH₋₃)(CO₃)] · 8H₂O (1) and [Ni₂(dmptH₋₂)₂] · 9.75H₂O (2) were elucidated by X-ray diffraction, and the complex [Co₂(dmptH₋₃)(μ-OH)] · NaClO₄ · 5H₂O (3) by XAS. The crystal structure of (1) shows that the two metallic centres are in a square planar environment. Each copper(II) is bound to pyridyl and deprotonated amidic nitrogen atoms and to the oxygen atoms of hydroxyl and carbonato groups. In complex (2), both nickel atoms are in a distorted octahedral environment with an identical set of donors atoms, N₄O₂, coming from four nitrogen atoms of two pyridylmethylamido moieties and two oxygen donor atoms of alcohol groups. XAS analysis of complex (3) allows us to propose a CoN₂O₄ chromophore, with two nitrogen atoms coming from pyridyl and amidic groups and two bridged oxygen atoms from a deprotonated alcohol group and an hydroxyl group; the hexacoordination is achieved by two water molecules. The spectroscopic, electrochemical and magnetic properties of these complexes were investigated.     

Crystal structure of {aquaimidazole-[2-(2-carbamoylhydrazone)-propionato]} copper(II) nitrate

The crystal structure of {aquaimidazole[2-(2-carbamoylhydrazone)-propionato]}copper(II) nitrate [Cu(L)Im(H₂O)]NO₃ (I), where HL is the semicarbazone of pyruvic acid, Im is imidazole, is dtermined. The crystal structure of I contains two independent complexes IA and IB in which copper atoms coordinate once deprotonated tridentate HL, imidazole, and water molecules. Outer spheres of the complexes contain nitrate ions. In the compounds studied the coordination polyhedron of the copper atom is a distorted tetragonal pyramid. Its base is composed of carboxyl and carbamide oxygen atoms, azomethine nitrogen of monodeprotonated HL molecules, and the imidazole nitrogen atom. In the crystal, nitrate ions and imidazole molecules link the complexes via hydrogen bonds into 2D networks parallel to the (010) plane. These networks in turn are in pairs arranged into layers along the [010] direction due to hydrogen bonds between water molecules and oxygen atoms of nitrate ions, and also by water molecules and O3 atoms of the neighboring 2D networks. In the crystal, the π-π stacking interaction is observed between the imidazole rings from different layers and there is also a N-O…Cg (π ring) interaction inside the layers.     

Bidentate bonding mode of tetrahydroborate and nitrite towards copper(II) in open-faced macrocyclic complexes

Novel seven-coordinate complexes formulated as [CuL(BH₄)₂], [CuL(BH₄)(NO₂)] and [CuL(NO₂)₂] (L = 1,4,7-triazacyclononane) have been prepared and structurally characterized by elemental analyses, spectroscopic data (u.v., i.r. and e.p.r.), magnetic susceptibility and conductivity measurements. The results reveal that the complexes are non-electrolytic. The coordination geometry around the copper(II) ion is a seven coordinated square pyramidal structure with three nitrogen atoms of the 1,4,7-triazacyclononane and either four hydrogen atoms of two bidentate tetrahydroborate groups or two hydrogen atoms of the bidentate tetrahydroborate group and two oxygen atoms of the bidentate nitrite group or four oxygen atoms of two bidentate nitrito groups. A cyclic voltammetric study on the complexes indicates an irreversible redox couple (Cu^II/Cu^I) in DMF, giving a voltage of ca. −0.37 V versus s.c.e.     

TRANSITION METAL COMPLEXES OF OLIGOTHIOETHER QUINOLYLOXY TERMINATED PODANDS: PART 2. CRYSTAL AND MOLECULAR STRUCTURE OF (1,8-BIS(QUINOLYLOXY)-3,6-DITHIAOCTANE)-COPPER(II) DIPERCHLORATE TRIHYDRATE

Abstract

The synthesis of the new ligand 1,8-bis(quinolyloxy)-3,6-dithiaoctane (1) and the corresponding Cu(II), Cu(I) and Co(II) complexes is reported. The crystal and molecular structure of the copper(II) complex, [Cu(1)](ClO₄)₂.3H₂O, has been determined by X-ray diffraction methods. The complex crystallizes in the orthorhombic space group Fddd, with cell data Z = 16, a = 20.326(2), b = 20.879(3) and c = 28.308(4)Å. The structure consists of discrete [Cu(1)]^?2+ cations separated by (structurally disordered) perchlorate anions and three lattice water molecules per cation. The coordination geometry about the copper atom is pseudo-octahedral with the quinoline nitrogen and thioether sulfur atoms at the equatorial positions and the ether oxygen atoms at the axial positions. ¹H NMR line-broadening experiments indicate that electron-transfer self-exchange reactions between the copper(I) and copper(II) complexes of (1) is immeasurably slow on the NMR time-scale. The coordination chemistry of (1) is compared with its oxygen analogue, 1,8-bis(quinolyloxy)-3,6-dioxaoctane.     

Tetradentate nitrogen-containing ligands bis-5-(2-pyridylmethylidene)-3,5-dihydro-4<Emphasis Type="Italic">H</Emphasis>-imidazol-4-ones and their coordination compounds with Cu<Superscript>I</Superscript> and Cu<Superscript>II</Superscript>

Tetradentate N₄-type organic ligands containing two 5-(2-pyridylmethylidene)-2-thio-3,5-dihydro-4H-imidazol-4-one fragments linked by two-, four-, or six-carbon polymethylene bridges between the sulfur atoms were synthesized. Mono- and dinuclear complexes of these ligands with copper(II) chloride, as well as with copper(I) and copper(II) perchlorates, were prepared. The structure of the coordination compound (5Z,5′Z)-2,2′-(butane-1,2-diyl-disulfanyldiyl)bis-5-(2-pyridylmethylidene)-3-phenyl-3,5-dihydro-4H-imidazol-4-one with copper(I) perchlorate was established by X-ray diffraction. The copper atom in this complex is in a distorted tetrahedral coordination formed by four nitrogen atoms of two imidazole and two pyridine rings. The perchlorate anion is located in the outer sphere of the complex and is not involved in the coordination with the copper ion. The electrochemical study of the ligands and the complexes was carried out by cyclic voltammetry and rotating disk electrode voltammetry. The initial reduction of the complexes under study occurs at the metal atom. The length of the polymethylene bridge in the ligand has only a slight effect on the redox properties of the ligands and the complexes.     

Interaction of copper(II) halides with 4-azafluorene derivatives in neutral and acid media. Crystal and molecular structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL<Superscript>4</Superscript>)<Subscript>2</Subscript>CuB<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

Complexes of copper(II) halides (chlorides and bromides) with some 4-azafluorene derivatives have been synthesized and studied by X-ray crystallography and IR and UV spectroscopy. In neutral media, Cu(L)₂X₂ (X = Cl, Br) complexes are formed in which the ligands are coordinated to the metal atoms though the lone pair of the endocyclic nitrogen atom and through the oxygen atoms of substituents. In acid media at pH 2, (HL²)₂CuX₄ complexes are formed in which the 4-azafluorene molecules protonated at the endocyclic nitrogen atom act as an outer-sphere cation. The molecule and crystal structure of 4-aza-9-oxofluorenium tetrabromocuprate hydrate (HL⁴)₂CuBr₄·H₂O has been determined.     

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)₂(SCN)] · ClO₄ (1) and a tetranuclear cobalt(II) complex [Co₄(L)₄(N₃)₄](OH)₄ · 2H₂O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN⁻ in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular π...π stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in μ-1,1-N₃ (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.     

Mixed-Anion Cu(II) Complexes with 3-(pyridin-2-yl)pyrazole (L), Syntheses and X-ray Crystal Structure of [Cu(L)2 Br]ClO4 (L=3-(pyridin-2-yl)pyrazole)

Reaction of the ligand 3-(pyridin-2-yl)pyrazole (L) with Cu(ClO₄)₂ and CuX₂ (X=Cl, Br, I) gives complexes with stoichiometry [Cu(L)₂X]ClO₄ (X = Cl, Br, I). The new complexes were characterized by elemental analyses and infrared and electronic spectroscopy. The crystal structure of the [Cu(L)₂Br]ClO₄ was determined by X-ray crystallography. The cation complex (i.e. [Cu(L)₂Br]P) contains copper(II) with a distorted trigonal bipyramid geometry with a Br^― ligand occupying an equatorial site. The penta-coordinated metal atom is bonded to two pyridinic nitrogens, two pyrazolic nitrogens, and one bromide anion. The pyrazolic H atoms are hydrogen bonded to Br atoms, resulting in infinite hydrogen-bonded chains running in the b direction. There are π‐π stacking interactions (charge-transfer arrays) between the parallel aromatic rings belonging to adjacent chains that may help to form hydrogen bonding in the coordination geometry around Cu (II).     

Novel ternary cobalt(II) and nickel(II) complexes of N-phthaloylglycinate. Synthesis, characterization and X-ray crystal structure

A new series of N-phthaloylglycineate (N-phthgly) ternary complexes of cobalt(II) and nickel(II) with imidazole (imi), N-methylimidazole (mimi) and 2,2′-bipyridyl (bipy) have been synthesized and characterized by elementary analyses, IR spectroscopy, thermogravimetric analysis. X-ray crystal structure analyses of the three complexes of [Co(mimi)₂(N-phthgly)₂] (1), [Co(bipy)(OH₂)₄](N-phthgly)₂ (2) and [Ni(imi)₂(N-phthgly)₂(OHCH₃)₂] (3) were also carried out. In complex (1), the Co(II) exists in a distorted tetrahedral enviroment, where two nitrogen atoms of two methylimidazole molecules and two oxygen atoms of the carboxylate group of two N-phthaloylglycinate molecules are coordinated. On the other hand, in complex (2) the cobalt atom coordinates a 2,2′-bipyridine molecule and four water oxygen atoms forming a distorted octahedral conformation. A molecule of N-phthaloylglycinate is connected by van der waals contact and H-bonds. For complex (3), the nickel atom is surrounded by four oxygens (two oxygens of two different N-phthaloylglycinate molecules and two of methanol ligand) in the basal plane of octahedron along with two imidazole nitrogen atoms at the apical positions. Strong intramolecular H-bond exists between the uncoordinated carboxylic oxygen of the N-phthaloylglycinate ligand and the O–H of the methanol group.