Synthesis,spectroscopic, and biological activities of two binuclear complexes [Cu(II)(1-phenylamidino-O-methylurea)2(H2O)]2(Cl2)2 and [Cu(II)(1-phenylamidino-O-i-butylurea)tmen]2(Cl2)2·2H2O

EPR spectra of two copper(II) binuclear complexes, [Cu(II)(1-phenylamidino-O-methylurea)₂(H₂O)]₂(Cl₂)₂ (1) and [Cu(II)(1-phenylamidino-O-i-butylurea)tmen]₂(Cl₂)₂?·?2H₂O (2), at room temperature showed fine structure transitions (ΔM _s?=?±1) and a very weak half-field signal corresponding to forbidden transitions (ΔM _s?=?±2). The spectrum of 1 showed disappearance of normal and half-field transitions when cooled to 77?K, suggesting antiferromagnetical coupling dicopper complex which is also supported by the low magnetic moments (µ _eff?=?1.64?B.M.). The isotropic exchange interaction constant J (41?cm^?1) for 2 indicated that interaction between the two spins of the binuclear complex is ferromagnetic, confirmed from the high magnetic moment value (µ _eff?=?2.25?B.M.). The binding of these complexes with calf thymus DNA suggested that these complexes interact with DNA by electrostatic or groove binding, not by intercalation. The two complexes have good antibacterial activity against tested bacteria responsible for urinary tract infection.     

X-ray study of volatile Ni(II), Cu(II), and Pd(II) complexes of β-ketoimine pivalyltrifluoroacetone

Synthesis of volatile complexes based on -ketoimine pivalyltrifluoroacetone, C(CH₃)₃C(NH)CH₂COCF₃, is described. The general formula of the complexes is M(L)₂, where M = Cu, Ni, Pd. Complexes of this kind with Ni and Pd were obtained for the first time. The Cu and Pd complexes were found to be isostructural. A comprehensive crystal-chemical study showed that all structures are molecular and built of trans-complexes. The central atom has a square plane environment. The average M-O and M-N distances are nearly equal in all compounds: 1.84 , 1.92 , and 1.98 for Ni, Cu, and Pd complexes, respectively; the mean values of the O-M-N chelate angles are 93.4°, 91.9°, and 92.7°, respectively.Original Russian Text Copyright © 2004 by I. A. Baidina, G. I. Zharkova, N. V. Pervukhina, S. A. Gromilov, and I. K. IgumenovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 713–722, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

The phenomenon of conglomerate crystallization in coordination compounds. XXIII: The crystallization behavior of [cis-Co(en)2(N3)(SO3)] · 2H2O (I) and of [cis-Co(en)2(NO2)(SO3)] · H2O (II)

A room temperature water solution of (I) crystallizes as a racemate, space groupP2 ₁/n with lattice constantsa=7.737(6),b=10.694(5),c=15.097(6) Å, and=102.83(5)°;V=1218.05 ų andd (calc; M.W.=337.24, Z=4) = 1.642 g cm^–3. A total of 2381 data were collected over the range 4° 2 < 50°; of these, 1452 (independent and withI 3(I)) were used in the structural analysis. Data were corrected for absorption ( = 15.76 cm^–1), and the relative transmission coefficients ranged from 0.8976 to 0.9984. Refinement led to the finalR(F) andR _w(F) residuals of 0.0858 and 0.1116. A room temperature water solution of (II) crystallizes as a racemate in space group P2₁/c with lattice constantsa=6.638(3),b=11.425(8),c=15.147(16) Å, and=93.27(6)°; F=1146.8 Å andd (calc; M.W.=323.2,Z=4) = 1.872 g cm^–3. A total of 2200 data were collected over the range 4° 2 < 50°; of these, 1918 (independent and withI 3(I)) were used in the structural analysis. Data were corrected for absorption (=16.94 cm^–1), and the relative transmission coefficients ranged from 0.9049 to 0.9967. Refinement led to the finalR(F) andR _w(F) residuals of 0.0231 and 0.0279. The chirality symbol for the particular enantiomer of (I) refined here is (), while for (II) the chirality symbol is (), which means that in the latter compound one of the en rings is in a higher energy conformation. We attribute this result to competitive intramolecular hydrogen-bonded interactions between the — NH₂ hydrogens of the en ligands and the oxygens of the -NO₂ and -SO₃ ligands, strengths which are enhanced by coercing a change in sign of the torsional angle of one en ringa motion which permits both oxo ligands to form stronger hydrogen bonds while retaining proper O O contacts. This phenomenon is not observed in (I) since the azide ligand does not compete with -SO₃ for such hydrogen-bonded interactions, and nonbonded pair repulsions can be minimized without affecting the ability of — SO₃ oxygens to form strong intramolecular hydrogen bonds.     

Crystal structure of [Cu2(Edta)(Py)2(H2O)2] · 2H2O and [Cu(Im)6]{;Cu(Im)4[Cu(Edta)(Im)]2} · 6H2O, Products of the interaction of (Ethylenediaminetetraacetato)diaquadicopper(II) with pyridine and imidazole

The crystals of [Cu₂(Edta)(Py)₂(H₂O)₂] · 2H₂O (I) and [Cu(Im)₆]{;Cu(Im)₄[Cu(Edta)(Im)]₂} · 6H₂O (II) were isolated as a result of the reaction of an aqueous solutions of Cu₂(Edta) · 4H₂O with pyridine or imidazole, respectively. The crystals were studied by X-ray diffraction. The crystals of I are monoclinic, a = 12.682 Å, b = 6.788 Å, c = 14.834 Å, β = 91.44°, Z = 2, space group P2₁/n. The crystals of II are triclinic, a = 9.118 Å, b = 14.889 Å, c = 15.130 Å, α = 72.59°, β = 72.94°, γ = 82.54°, Z = 1, space group P{ie241-1}. In the centrosymmetric binuclear complex molecule of I, an N atom and two O atoms of the Edta ligand are coordinated to each Cu atom (Cu-N, 2.046 Å; Cu-O, 1.941 and 1.954 Å). The N atom of the pyridine molecule (Cu-N, 1.993 Å) completes the base of an elongated tetragonal pyramid (4 + 1) with the O atom of the H₂O molecule in the apex (Cu-O(w), 2.244 Å). The crystals of II are built of centrosymmetric complex cations [Cu(Im)₆]²⁺ (Cu(1)-N, 2.469, 2.021, and 2.056 Å), centrosymmetric trinuclear complex anions {;Cu(Im)₄[Cu(Edta)(Im)]₂}^2?, and crystal water molecules. In the anion, the central fragment [Cu(Im)₄]²⁺ (Cu(2)-N, 1.985 and 2.023 Å) is bonded to two peripheral complexes [Cu(Edta)(Im)]^2? through atoms O of the Edta ligand (Cu(2)-O, 2.615 Å). In the [Cu(Edta)(Im)]^2? fragment of the complex anion, the Cu(3) atom is bonded to the Edta ligand through the two N atoms and three O atoms (Cu(3)-N, 1.970 and 2.071 Å; Cu(3)-O, 1.966, 1.969, and 2.238 Å) and with the imidazole molecule, through an N atom (Cu(3)-N, 2.397 Å). The coordination polyhedra of the three copper atoms (Cu(1)-Cu(3)) in the structure of II are elongated tetragonal bipyramids (4 + 2). In the structures studied, Edta^4? is a hexadentate chelating/bridging ligand. However, the coordination mode of the ligand in these structures is different: in the binuclear complex I, the Edta ligand is coordinated to each Cu atom through an N atom and two O atoms with the formation of two chelate rings (symmetric (trans) coordination mode), whereas, in the trinuclear complex II, the Edta ligand is coordinated to the Cu(2) atom through an O atom and to the Cu(3) atom through the two N atoms and three O atoms with the formation of three chelate rings (asymmetric (cis) coordination mode).     

Synthesis and Crystal Structure of a New Complex [Bis(dien)zinc(II)] Zinc(II) Tetrachloride (dien = Diethylenetriamine)

The title complex [bis(dien)zinc(II)] zinc(II) tetrachloride was synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, electric conductivity, IR and electronic spectra. The compound crystallizes in the tetragonal system, space group I4 with a = 10.250(3), b = 10.250(3), c = 9.054(2) -, V = 951.2(5) 3, Mr = 486.95, Z = 2, F(000) = 504, Dc = 1.700 g/cm3, μ = 3.083 mm-1, λ = 0.71073 , the final R = 0.0226 and wR = 0.0642. The symmetric crystal structure consists of a zinc complex cation [Zn(dien)2]2+ and a zinc tetrachloride anion [ZnCl4]2-, forming a three-dimensional framework through intramolecular and intermolecular hydrogen bonds.     

Synthesis and Crystal Structure of a Macrocycle [Cu(dadm)(mal)(H2O)]2·2H2O

The reaction of 4,4′-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]2(2H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2)A,Z= 106.75(3)o, V = 1693.5(6)A3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, λ(MoK() = 0.71073A, μ = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and Wr = 0.1244 for 3421 observed reflections with I > 2σ(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3A× 5.9A.     

Antimicrobial studies of N - N ′-dicarboxydiethyloxamide and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

Neutral complexes of Cu(II), Ni(II), Co(II), and Zn(II) have been synthesized from the oxamide-based ligand derived from leucine and diethyloxalate. The structural features have been deduced from their microanalytical, IR, UV/Vis, mass, ¹H and ¹³C NMR spectral data. The Co(II) and Ni(II) chelates have octahedral geometries and the Cu(II) chelate is a square-pyramidal geometry. The non-electrolytic and monomeric nature of the complexes is shown by their magnetic susceptibility and low conductance data. The biological activities of the ligand and its metal chelates against gram-positive and negative bacteria and fungi are also reported. All the compounds are antimicrobially active and show higher activity than the free ligand.     

[Cu(β-ala)(phen)(H2 O)]·NO3 ·H2O的合成与晶体结构

在pH为3的醇水混合溶剂中合成了β-丙氨酸、1,10-邻菲咯林、铜的三元配合物,测定了配合物的晶体结构.晶体属单斜晶系,Pī空间群,晶胞参数a=1.0045(2) nm, b=1.2132(2) nm, c=0.71682(14) nm, α= 93.88(3)°, β= 94.31(3)°, γ= 99.81(3)°, V=0.8555(3) nm3, Z=2, Dc=1.669 Mg·m-3, μ=1.326 mm-1, F(000)=442, R=0.0457, Rw=0.1179.配合物中铜离子的配位数为5,分子间通过氢键构成三维网状结构.     

Thermal behaviors of N-pyrrolidine-N′-(2-chlorobenzoyl)thiourea and its Ni(II), Cu(II), and Co(III) complexes

The N-pyrrolidine-N??-(2-chlorobenzoyl)thiourea, HL, and their Ni(II), Cu(II), and Co(III) complexes (NiL₂, CuL₂, and CoL₃) have been synthesized and characterized. The thermal decomposition reactions of all the compounds have been investigated by DTA/TG combined systems. The mass spectroscopy technique has been used to identify the products during pyrolytic decomposition. The pyrolytic final products have been analyzed by X-ray powder diffraction method. After comparison of thermogravimetric and mass results of HL, NiL₂, CuL₂, and CoL₃, the decomposition mechanism of these compounds have been suggested. The thermal stability of the Ni(II) and Cu(II) complexes according to the thermogravimetric curves follows the sequence: NiL₂?<?CuL₂. The values of the activation energy, E _a, have been obtained using model-free (Kissenger?CAkahira?CSunose, KAS, Flyn?CWall?COzawa, FWO, and Isoconversional) methods for all decomposition stages. The E _a versus the extent of conversion, ??, plots show that the values of E _a varies as ??. Thirteen kinetic model equations have been tested for selecting correct reaction models. The optimized value of E _a and Arrhenius factor, A, have been obtained using the best model equation. The thermodynamic functions (??H*, ??S*, and ??G*) have been calculated using these values.     

Synthesis,crystal structure,and magnetic properties of a new end-to-end thiocyanato-bridged dicobalt(II) complex CoII(dien)(H2O)(NCS)(μ1,3-NCS)CoII(dien)(NCS)2 (dien = diethylenetriamine)

Synthesis, characterization, crystal structure, and magnetic properties of the first single µ_1,3-thiocyanato-bridged dicobalt(II) compound, [Co^II(dien)(H₂O)(NCS)(µ_1,3-NCS)Co^II(dien)(NCS)₂] (1; dien = diethylenetriamine), are described. In 1, cobalt(II) is six coordinate with distorted-octahedral geometry. The Co(1) ··· Co(2) distance is 5.99 Å. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility measurements. The metal centers are coupled by weak ferromagnetic interaction (J = 1.14 cm^?1). The structure and magnetic properties are compared with related thiocyanate-bridged compounds.     

Synthesis and Crystal Structure of a Macrocycle [Cu(dadm)(mal)(H_2O)]_2·02H_2O

1 INTRODUCTION Recently the self-assembly through transition metal and N-containing organic ligands has appear- ed as a popular research field in supramolecular architecture. Among the N-donor organic ligands, the rigid ligands have been well investigat…     

Synthesis and Structure of Catena-[Bis(2-Methylimidazole)(μ-Phthalato)cobaltate(II)]

A new coordination compound [Co(Pht)(2-MeIm)₂] (I), where Pht^2–is the deprotonated radical of o-phthalic acid (H₂Pht) and 2-MeIm is 2-methylimidazole, was synthesized. Its structure was established using X-ray diffraction analysis. The crystal is orthorhombic: space group Pca2₁, a= 15.350(3), b= 7.957(2), c= 13.997(3) Å, (calcd.) = 1.505 g/cm³, and Z= 4. The tetrahedral coordination of the Co(II) atom includes two N atoms of two 2-methylimidazole molecules and two oxygen atoms of two carboxyl groups from different acid radicals. The Co–N distances are equal to 2.022(2) and 2.031(2) Å, while the Co–O distances are 1.972(2) and 2.000(2) Å. The carboxyl groups of the Pht^2–radical and the aromatic nucleus form angles of 47.2° and 35.9°, whereas the angle formed by the carboxyl groups themselves is 50.3°. Compound Iis a polymer, which is confirmed by the 1,6-bridging function of the o-phthalic acid radical. The Co···Co distance in a chain is equal to 7.367 Å. Separate chains are united in the crystal into a framework via N–H···O hydrogen bonds.     

Uncommon Behavior of Copper(I) Tetrafluoroborate and Perchlorate in [Cu(DAF)(H2O)]BF4and [Cu(DAF)(ClO4)] π-Complexes (DAF—Diallyl Formamide)

Crystals of [Cu(DAF)(H₂O)]BF₄(I) and [Cu(DAF)(ClO₄)] (II) (DAF is diallyl formamide) were synthesized by an alternate-current electrochemical method, and their structures were determined (MoK radiation, 1247 and 859 independent reflections with I 2(I), R= 0.043 and 0.032 for Iand II, respectively). The complexes crystallize in space group P2₁/n, Z= 4. For I, a= 10.782(3) Å, b= 12.096(5) Å, c= 9.185(3) Å, = 103.62(3)°, and V= 1164.2(7) ų; for II, a= 10.064(3) Å, b= 10.753(6) Å, c= 10.002(3) Å, = 87.52(4)°, and V= 1081.4(8) ų. The copper atom in structures Iand IIcoordinates both C=C bonds in one DAF molecule and oxygen atom of the amide group of another DAF molecule, as well as an oxygen atom of H₂O (in I) or ClO₄(in II) in the axial position. The uncommon behavior of the anions in structures Iand IIis explained by their different values of Pierson hardness.     

The coordination chemistry of mono and bis(di-2-pyridylamine)copper(II) complexes: preparation,characterization and crystal structures of [Cu(L)(NO2)2], [Cu(L)(H2O)2(SO4)], [Cu(L)2(NCS)](SCN)·0.5DMSO and [Cu(L)2(SCN)2]

The crystal structures of two mono(dpyam)copper(II) complexes, [Cu(dpyam)(NO₂)₂] (1) and [Cu(dpyam)(H₂O)₂(SO₄)] (2) and two dithiocyanate compounds containing bis(dpyam)copper(II) units, [Cu(dpyam)₂(NCS)](SCN)·0.5DMSO (3) and [Cu(dpyam)₂(SCN)₂] (4) have been determined by X-ray crystallography. The second orthorhombic form of the monomeric Cu(II) complex 1 was obtained by the reaction of di-2-pyridylamine (dpyam) with CuCl and NaNO₂ in water–methanol solution. Each copper(II) ion in 1 exhibits a tetrahedrally-distorted square base of the CuN₂O₂ chromophore, with off-the-z-axis coordinated nitrito groups weakly bound in approximately axial positions. Complex 2 is an example of a polymeric copper(II) derivative containing the bidentate bridging sulfate ligand in the long-bonded axial positions. Each copper(II) ion in 2 shows an elongated tetragonal octahedral stereochemistry. The CuN₄N′ chromophore of 3 involves a square-based pyramidal structure, slightly distorted towards a trigonal bipyramidal stereochemistry, τ=0.13. One of the SCN⁻ anions is bonded to the copper(II) ion via the N atom in the axial position of the square pyramid. Complex 4 is centrosymmetric and octahedrally elongated, with the SCN⁻ anions coordinating in axial positions via the S atom. The structures of complexes 1–4 and their ESR and electronic reflectance spectra are compared with those of related complexes.     

Synthesis and Structural Studies of Some β-Diketone Phenylhydrazones and their Complexes with Co(II), Ni(II), and Cu(II)

Summary.  New β-diketone phenylhydrazones prepared by condensation of substituted 3-arylidene-2,4-pentanediones with phenylhydrazine, have been characterized by their elemental analyses, IR, ¹H NMR, and mass spectra. Some complexes of these Schiff bases with Co(II), Ni(II), and Cu(II) ions have been synthesized; in addition to the above methods, their structures were studied by magnetic susceptibility and thermogravimetry measurements. Received January 26, 2000. Accepted (revised) April 14, 2000     

Nickel(II), copper(II), palladium(II) and platinum(II) complexes of bidentate SN ligands derived from S-alkyldithiocarbazates and the X-ray crystal structures of the [Ni(tasbz)2] and [Cu(tasbz)2] · CHCl3 complexes

New complexes of general empirical formula, [M(NS)₂] · nCHCl₃ (M = Ni^II, Cu^II, Pd^II or Pt^II; NS = anionic form of the thiophene-2-aldehyde Schiff bases of S-methyl- and S-benzyldithiocarbazate; n = 0, 1) have been synthesized and characterized by physico-chemical techniques. Magnetic and spectroscopic evidence support a square-planar structure for these complexes. The crystal structures of the [Ni(tasbz)₂] and [Cu(tasbz)₂] · CHCl₃ complexes (tasbz = anionic form of the thiophene-2-aldehyde Schiff base of S-benzyldithiocarbazate) have been determined by X-ray diffraction. Both complexes have a trans-planar structure in which the two Schiff base ligands are coordinated to the metal(II) ion as uninegatively charged bidentate ligands via the thiolate sulfur and the azomethine nitrogen atoms. This revised version was published online in June 2006 with corrections to the Cover Date.     

Bimetallic palladium(II) and iron(III), titanium(IV), vanadium(V), cobalt(II), and copper(II) complexes with the [As2W19O67(H2O)]14− heteropolyanion

The formation of bimetallic Pd(II) and M = Fe(III), Ti(IV), V(V), Co(II), or Cu(II) complexes with the two-vacancy [As₂W₁₉O₆₇(H₂O)]^14? heteropolyanion (HPA) (below referred to as As₂W₁₉) has been studied by UV/Vis and IR spectroscopy and differential dissolution. In an aqueous solution at pH 6 and a Pd: M: As₂W₁₉ molar ratio of 1: 1: 1, heteropoly complexes (HPC) incorporating two different metals one being Pd(II) are formed. The resulting complexes were precipitated from solution as cesium salts. In the case of Pd(II) and M = Fe(III), Co(II), or Cu(II) ions, the precipitate contained bimetallic HPC [As₂W₁₉FePDO₆₇(H₂O)₂]^9? (65.9 wt %), [As₂W₁₉CoPdO₆₇(H₂O)₂]^10? (45.6 wt %), and [As₂W₁₉CuPdO₆₇(H₂O)₂]^10? (50.7 wt %) mixed with monometallic HPC [As₂W₁₉M₂O₆₇(H₂O)₂]^{(14 ? 2m)?} (As₂W₁₉M₂). In the case of Pd(II) and Ti(IV) or V(V), bimetallic HPC of a different composition were precipitated, namely, [As₂W₁₉Ti₂O₆₇(OH _x )₂ PdO]^{(10 ? 2x)?} (76.8 wt %) and [As₂W₁₉V₂O₆₇(OH _x )₂ PdO]^{(8 ? 2x)?} (15.0 wt %), where palladium ions are not incorporated in the HPC structure but are attached to the HPC surface, possibly, as hydroxide species. Using M = Pd(II), Ti(IV), V(V) ions and the HPA As₂W₁₉ ([M]: [As₂W₁₉] = 2 : 1, pH 6), new monometallic HPC, [As₂W₁₉Pd₂O₆₇(H₂O)₂]^10?, [As₂W₁₉Ti₂O₆₇(OH _x )₂]^{(10 ? 2x)?}, and [As₂W₁₉V₂O₆₇(OH _x )₂]^{(8 ? 2x)?} (x = 0, 1, or 2), were obtained.     

Preparation, spectral and thermal properties of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes with iodosubstituted 2,2′-dipyrrolylmethene

Complexes [ML₂] of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with asymmetrically substituted (E)-3-ethyl-5-[(4-iodo-3,5-dimethyl-2H-pyrrol-2-ylidene)methyl]-2,4-dimethyl-1H-pyrrole (HL) have been prepared and characterized for the first time. The spectral properties, stability in solutions and in the solid phase at elevated temperature of the complexes have been studied. The effects of complexing metal ion and the reaction medium on the spectral luminescent properties (absorptivity, quantum yield, fluorescence lifetime, and the radiation constant) and on thermal destruction of the [ML₂] complexes have been discussed.     

The crystal and molecular structures of aqua(1,4,7,10,13-pentaazacyclopentadecane)nickel(II) nitrate perchlorate [Ni[15]aneN5·H H2O](NO3)(ClO4) and (1,5,9,13,17-pentaazacycloeicosane)-nikel(II) nitrate hydrate [Ni[20]aneN5](NO3)2·H2O

Summary The structures of Ni^II complexes of the macrocyclic ligands 1,4,7,10,13-pentaazacyclopentadecane, [15]aneN₅ and 1,5,9,13,17-pentaazacycloeicosane, [20]aneN₅ have been determined. [Ni(C₁₀H₂₅N₅)H₂O]-(NO₃)(ClO₄) monoclinic, space group P2₁/n,a=8.265(3)Å,b=6.201(6)Å,c=13.672(4)Å, =93.35(3)°· 2394 unique reflections were used in the structure determination and the refinement proceeded to an R value of 0.045. The ligand is coordinated to the metalvia all five nitrogens in theracemic conformation and a water molecule completes the coordination sphere of the metal ion. The complex cation shows considerable distortion from octahedral geometry which may rationalise the unusual spectroscopic properties and the low enthalpy of formation of the complex cation. [Ni(C₁₅H₃₅N₅)](NO₃)₂·H₂O monoclinic, space group P2₁/n,a=15.437(9)Å,b=9.573(6)Å,c=15.942(8)Å, =109.24(4)°. 2715 unique observed reflections were used in the structure refinement which proceeded to an R value of 0.035. The five nitrogens of the macrocycle are bound to Ni(II) in a distorted square pyramidal coordination geometry. The Ni^II lies 0.35Å above the basal plane of the four nitrogen atoms.     

Crystal Structure of Calcium [Aqua(Nitrilotriacetatocobaltate(II)] Tetrahydrate,Ca[Co(Nta)(H2O)]2· 4H2O

Crystals of Ca[Co^II(Nta)]₂· 6H₂O (I), where Nta^3–is a nitrilotriacetate ion, were synthesized and studied using X-ray diffraction analysis. They were found to be monoclinic: a= 6.991(1), b= 10.031(1), c= 16.238(3) Å, = 98.50(1)°, V= 1126.2(3) ų, space group P2₁/n, Z= 2, R ₁= 0.0241, wR ₂= 0.0636, GOOF = 1.050 (for 3132 reflections with I> 2(I)). Structure Iis composed of {[Co(Nta)(H₂O)]^–}₁anion chains united by Ca²⁺cations into a three-dimensional framework. The coordination polyhedra of Co and Ca atoms are distorted octahedra. The Co(II) atom environment includes atoms N(1), O(1), O(3), and O(5) of one Nta^3–ligand, a carbonyl O(2)" atom of the neighboring anion fragment, and an O(w1) atom of the water molecule. The shortest bond is formed by the Co atom with the bridging O(2)" atom in trans-position relative to atom N(1). The Co–O(2)" distance (2.029 Å) is noticeably shorter than the other bond lengths, Co–O(Nta) (2.069–2.103 Å), Co–O(w1), and Co–N(1) (2.155 and 2.177 Å, respectively). Cations Ca²⁺are located in the inversion centers and involve in their coordination atoms O(4), O(6), O(w2), and the oxygen atoms symmetrically bond to them and arranged at 2.271(1), 2.420(1), and 2.351(2) Å, respectively. The structural formula of the title compound is {Ca(H₂O)₂[Co(Nta)(H₂O)]₂}₃· 2H₂O.