Kristallstrukturänderungen des Magnesiumnitrats-Hexahydrats,die infolge isodimorpher Substitution durch Co(II)- und Ni(II)-Ionen entstehen

The physico-chemical analysis data on the systems Mg(NO₃)₂ Co(NO₃)₂ H₂O and Mg(NO₃)₂ Ni(NO₃)₂ H₂O at 25.0°C have shown that due to isodimorphous substitution of Mg²⁺ in the crystals of Mg(NO₃)₂ · 6 H₂O for Co²⁺ or Ni²⁺, above a specific degree of ionic substitution, changes in the crystal structure of Mg(NO₃)₂ · 6 H₂O appear.     

Structures of transition and alkaline earth metal salts of 5-aminonaphthalene-2-sulfonate and 6-aminonaphthalene-1, 3-disulfonate: Some unusual coordination behaviors

Salts of 5-aminonaphthalene-2-sulfonate with divalent Mg, Mn, Co, and Ni cations have been crystallized and their structures determined by single crystal X-ray methods. The Mg, Mn, and Co salts are isostructural. Crystal data for hexaaquamagnesium(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Mg(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.1329(18) ?, b=8.5789(11) ?, c=12.4880(17) ?, β=93.374(3)°, V=1511.5(3) ?³; hexaaquamanganese(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Mn(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.249(3) ?, b=8.5940(17) ?, c=12.505(3) ?, β=93.30(3)°, V=1528.8(6) ?³; hexaaquacobalt(II) 5-aminonaphthalene-2-sulfonate hexahydrate, [Co(H₂O)₆](H₂NC₁₀H₆SO₃)₂·6H₂O: monoclinic, P2₁/c, Z=2, a=14.1406(18) ?, b=8.5674(11) ?, c=12.4960(16) ?, β=93.297(2)°, V=1511.4(3) ?³. The structures are composed of alternating layers of octahedral metal–aqua complexes and sulfonate anions linked by hydrogen bonds. The three water molecules of crystallization are associated with the hexaaquametal cations and sulfonate O atoms. The repeat unit along the a-axis is a single layer. The Ni salt [crystal data for tetraaquabis(5-aminonaphthalene-2-sulfonato-N)nickel(II) dihydrate, [Ni(H₂O)₄(H₂NC₁₀H₆SO₃)₂]·2H₂O: triclinic, , Z=1, a=6.8524(10) ?, b=8.3094(12) ?, c=11.4832(17) ?, α=69.003(2)°, β=76.570(3)°, γ=83.952(2)°, V=593.56(15) ?³] has a very different structure with direct coordination of the amine N atom to Ni, a modified stacking pattern, and fewer free water molecules. Ag and Ni salts of an amine-substituted naphthalenedisulfonate have also been characterized. Crystal data for diaqua(6-ammonionaphthalene-1,3-disulfonato-O)silver(I) hydrate,[Ag(H₂O)₂(H₃NC₁₀H₅(SO₃)₂)]·0.42H₂O: monoclinic, P2₁/c, Z=2, a=9.099(3) ?, b=21.406(6) ?, c=7.629(2) ?, β=110.178(4)°, V=1394.9(7) ?³; tetraaquabis (6-ammonionaphthalene-1,3-disulfonato-O)nickel(II)tetrahydrate, [Ni(H₂O)₄(H₂NC₁₀H₅ (SO₃)₂)₂]·4H₂O: triclinic,, Z=1, a=6.7971(17) ?, b=10.661(3) ?, c=11.165(3) ?, α=68.308(4)°, β=88.292(5)°, γ=84.896(5)°, V=748.8(3) ?³. The silver salt contains six coordinate metal centers each of which bonds to four sulfonate O atoms from three different anions and two water molecules. The nickel salt contains octahedral cations with four water molecules and two trans sulfonate O atoms. Both structures are layered, but differently from each other and from those of the monofunctional naphthalenesulfonate salts.Unusual coordination of a sulfonate group to a transition metal and coordination of an amine group to nickel but not to cobalt or manganese have been observed in a series of metal aminonaphthalenesulfonate salts     

Effect of citric acid concentration as emulsifier on perovskite phase formation of nano‐sized SrMnO3 and SrCoO3 samples

In this study the effects of citric acid concentration, used as organic emulsifier, on the perovskite phase formation of the nano strontium manganite or cobaltite samples were studied. Stoichiometric perovskites in the absence and presence of citric acid were prepared by drying a solution containing molar ratio of Sr(NO₃)₂/Mn(NO₃)₂·4H₂O and Sr(NO₃)₂/Co(NO₃)₂·6H₂O = 1 followed by calcination at 900 °C for 5 h. Citric acid concentration, selected to be 0.0, 0.3, 0.6, 1.0, 1.3, 2.5 and 5 times of the total number of moles of the nitrate ions. The results revealed that increase in the citric acid concentration, larger than number of moles of the nitrate ions equivalent, deteriorates the perovskite phase formation. Instead, a new phase of carbonates and metal oxides are appeared. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth of R 2 Me(SO4)2 · 6H2O single crystals with due regard for solubility diagrams of the R 2SO4-MeSO4-H2O systems (R = K, NH4; Me = Ni, Co)

The optimum conditions for growing R ₂ Me(SO₄)₂ · 6H₂O crystals are found from the analysis of the _{R 2} ⁺ SO₄-Me ²⁺SO₄-H₂O systems (R = K, NH₄; Me = Ni, Co) in the temperature range from 55 to 25°C. A new economical technology for growth of single crystals of double sulfate hexahydrates is developed, which allows the use of starting presynthesized solutions of hydrated or anhydrous K, Ni, Co, and (NH₄) sulfates. Transparent K₂Ni(SO₄)₂ · 6H₂O, K₂Co(SO₄)₂ · 6H₂O, and (NH₄)₂Ni(SO₄)₂ · 6H₂O crystals (35–55) × (25–40) × 10 mm in size are grown on seeds by the method of slow cooling.     

Synthesis, Crystal Structure of a New Co(II) Complex with Pyrazine-2,3,5,6-tetracarboxylic Acid

Abstract A new complex [Co(H₂pztc)(bpy)H₂O] (H₄pztc = pyrazine-2,3,5,6-tetracarboxylic acid, bpy = 2,2′-bipyridine) has been synthesized by hydrothermal reactions of Co(NO₃)₂ · 6H₂O with H₄pztc and bpy and characterized by IR and X-ray diffraction single crystal structure analysis. It belongs to monoclinic system, P2₁/c space group with a = 13.454(2) ?, b = 12.939(2) ?, c = 11.4993(19) ?, α = 90°, β = 111.640(3)°, γ = 90°. This complex is assembled into 3D supramolecular architecture by hydrogen bonds (O–H···O, C–H···O). Index Abstract A new complex of cobalt(II) with pyrazine-2,3,5,6-tetracarboxylic acid and 2,2′-bipyridine is assembled by intermolecular hydrogen bonds forming 2D layer and 3D supramolecular network.      

A study of the mechanisms of defect formation in K2Ni(SO4)2 · 6H2O/K2Co(SO4)2 · 6H2O bicrystals grown from aqueous solutions

The K₂Co(SO₄)₂ · 6H₂O-K₂Ni(SO₄)₂ · 6H₂O system has been studied, and a series of K₂Ni(SO₄)₂ · 6H₂O/K₂Co(SO₄)₂ · 6H₂O bicrystals have been grown. The processes of defect formation at the substrate/layer interface K₂Co(SO₄)₂ · 6H₂O/K₂Ni(SO₄)₂ · 6H₂O are studied by probe microanalysis, X-ray topography, and optical microscopy. It is found that inclusions and threading dislocations are formed at the interface, due to which elastic stresses relax in the crystal. Nickel is nonuniformly distributed in the layer; its concentration decreases with an increase in the layer thickness, which is indicative of substrate dissolution in the initial stage of interaction. A way for the elastic mismatch stresses to relax in heterostructures of brittle crystals obtained from solutions at low temperatures is proposed which implies the formation of inclusions at the substrate/layer interface. Original Russian Text ? M.S. Grigor’eva, A.é. Voloshin, E.B. Rudneva, V.L. Manomenova, S.N. Khakhanov, V.Ya. Shklover, 2009, published in Kristallografiya, 2009, Vol. 54, No. 4, pp. 679–687.     

Crystal Structure of a Second Polymorph of Gabapentin Hydrochloride Hemihydrate with a Three-Center Bifurcated Hydrogen Bond

Abstract  

Gabapentin hydrochloride hemihydrate, a derivative of Gabapentin [or 1-(aminomethyl) cyclohexaneacetic acid; Gpn, C₆H₁₇NO₂], is a salt of C₉H₁₈NO₂ ⁺ Cl⁻ 0.5 H₂O, which crystallizes in the monoclinic space group I 2/a with unit cell parameters a = 13.2467(3), b = 6.5552(2), c = 26.0094(8) ?, β = 96.561(3)°, Z = 8. The crystal structure and bonding network is compared to its isostructural and previously reported polymorphic derivative, Gpn hydrochloride hemihydrate [C₉H₁₇NO₂ HCl ? H₂O]. Both of these derivatives exhibit extensive inter and intra molecular hydrogen bonding networks between the NH₃ ⁺ group and neighboring Cl⁻, water and carboxyl oxygen atoms as well as similar interactions between the chloride anion and nearby water and carboxyl oxygen atoms. A unique and relatively rare three-center hydrogen bond configuration (with a bifurcated chlorine Cl⁻···H–(N,O) and Cl⁻···H–O acceptor hydrogen bonds) as well as N–H···O donor hydrogen bonds can be seen linking the molecules into chains along the [1 0 1] plane of the unit cell.     

The synthesis and structure of a novel alternating 1-D cobalt coordination polymer [Co(2,5-PDC)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>Co(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>]·4H<Subscript>2</Subscript>O

A novel cobalt complex [Co(2,5-PDC)₂(H₂O)₂Co(H₂O)₄]·4H₂O (2,5-PDCH₂ = 2,5-pyridinedicarboxylic acid) was synthesized and its crystal structure has been determined by X-ray diffraction. The crystallographic data are: triclinic P−1, a = 7.112(2) ?, b = 8.939(3) ?, c = 9.719(3) ?, α = 91.153(5)°, β = 101.136(5)°, γ = 108.001(4)°, V = 574.4(3) ?³, Z = 1. The compound [Co(2,5-PDC)₂(H₂O)₂Co(H₂O)₄]·4H₂O exhibits a novel one-dimensional network constructed from the interconnection of Co(2,5-PDC)₂(H₂O)₂ and Co(H₂O)₄, in which two kinds of six-coordinated Co(II) atoms have both octahedral coordination environments. Each 2,5-PDC anion connects two different coordinated cobalt ions alternately in an one-dimensional chain. The zigzag 1D alternating chains are linked by extensive hydrogen bonds to form a three-dimensional (3D) supramolecular structure, in which uncoordinated solvate molecules act as space filling particles. Supplementary data CCDC-264249 contains the supplementary crystallographic data for this paper. Copies of this information may be obtained free of charge from the Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: t44–1223–336033; e-mail: deposit@ccdc.cam.ac.uk or ) or also available from the author Xiaoqing Wang.     

Crystal Structure of [Co(NH3)5NO3](NO3)(PF6)?·?1.5H2O and the Vibrational Bands of its Normal and 15NO3-Enriched Cation

The crystal structure of [Co(NH₃)₅NO₃](NO₃)(PF₆) ·1.5 H₂O was studied by X-ray diffraction methods in order to obtain the unknown molecular structure of the [Co(NH₃)₅NO₃]²⁺ cation . The substance crystallizes in the monoclinic system, space group C2/m, with a = 18.6231(6) ?, b = 7.8757(3) ?, c = 9.6434(3) ? and β = 95.484(2)°. An infrared and Raman study of the bromide salt was also performed and the spectra interpreted with the aid of ¹⁴NO₃/¹⁵NO₃ isotopic replacement and quantum chemistry calculations. E.L. Varetti — Member of the Carrera del Investigador Científico, CONICET, R. Argentina     

Syntheses and crystal structures of an organometallic thiosemicarbazone and an organometallic enehydrazide

Reactions of ferrocenoylacetone with thiosemicarbazide and isonicotinic acid hydrazide generate an organometallic thiosemicarbazone 1 and enehydrazide 2, respectively. The complexes 1 and 2, which can be formulated as [C₅H₅FeC₅H₄C(O)CH₂C(=NNHCSNH₂)CH₃] and [C₅H₅FeC₅H₄C(O)CH=C(NHNHCOC₅H₄N-4)CH₃], have been characterized by elemental analyses, IR, NMR, UV and were structurally characterized by single-crystal X-ray crystallography. Complex 1 (C₁₅H₁₇FeN₃OS) crystallizes in the monoclinic space group P2₁/c, with lattice constants: a = 13.939(3) ?, b = 8.2600(17) ?, c = 13.176(3) ?, β = 94.83(3)°, V = 1511.7(6) ?³, Z = 4, D _c = 1.508 g cm⁻³, F(000) = 712, R ₁ = 0.0602, wR ₂ = 0.1526. Two intermolecular hydrogen bonds N–H···S (N···S = 3.356(8) and 3.499(7) ?, N–H···S = 168 and 170°) form a chain in the [010] direction. The intermolecular hydrogen bond C–H···O (C···O = 3.432(10) ?, C–H···O = 151°) leads to a [010] double-chain through each unit cell. The intermolecular hydrogen bond C–H···O (C···O = 3.359(10) ?, C–H···O = 173°) makes the [010] double-chain pack along the c axis to result in a two-dimensional network. Complex 2 (C₂₀H₁₉FeN₃O₂) crystallizes in the monoclinic space group P2₁/c, with lattice constants: a = 14.091(2) ?, b = 10.024(2) ?, c = 13.806(2) ?, β = 112.41(2)°, V = 1802.8(6) ?³, Z = 4, D _c = 1.434 g cm⁻³, F(000) = 808, R ₁ = 0.0576, wR ₂ = 0.1593. The strong intramolecular hydrogen bond N–H···O from the enamine N atom and carbonyl O atom stabilizes the enehydrazide. The intermolecular hydrogen bonds N–H···O and C–H···O (N···O = 2.906(6) ?, N–H···O = 155° C···O = 3.364(6) ?, C–H···O = 153°) generate a [010] chain. The intermolecular hydrogen bond N–H···O (N···O = 2.989(6) ?, N–H···O = 128°) forms a [010] double-chain through each unit cell. The π···π stacking interation involving the pyridyl groups makes the [010] double-chain pack along the c axis to lead to a two-dimensional network.     

Formation of solution inclusions in bicrystals of potassium-cobalt/potassium-nickel and ammonium-cobalt/ammonium-nickel sulfates

The crystallization of epitaxial layers from aqueous solutions in the K₂Co(SO₄)₂ · 6H₂O-K₂Ni(SO₄)₂· 6H₂O and (NH₄)₂Co(SO₄)₂· 6H₂O-(NH₄)₂Ni(SO₄)₂ · 6H₂O systems has been studied. A mechanism is proposed to explain the experimentally observed phenomena, taking into account the effect that elastic stresses have on the crystallization kinetics.     

Optical properties of non‐centrosymmetric mixed crystals K2(La1‐x Cex)(NO3)5 · 2 H2O (x = 0.0 – 1.0)

Large single crystals of optical quality of the non‐centrosymmetric orthorhombic potassium rare earth nitrate mixed crystals K₂(La_1–x Ce_x)(NO₃)₅ · 2 H₂O were grown at 38 °C from diluted HNO₃. For crystals with x = 0.0, 0.19, 0.38 and 0.66 refractive indices and their dispersion were determined with an error less than 1 · 10^–4 in the wavelength range 0.404 – 1.083 μm by the prism method. Phase matching conditions for collinear SHG frequency conversion were analysed in detail, including calculation of the effective nonlinear optical susceptibility. By an appropriate choice of the fraction x of cerium the mixed crystals K₂(La_1–x Ce_x)(NO₃)₅ · 2 H₂O allow an adjustment of non‐critical type I phase matching conditions to a desired wavelength of the fundamental wave within the range 1.055(4) – 1.107(6) μm. Non‐critical type II phase matching can be tuned in the wavelength range 0.949(2) – 0.931(2) μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of octapotassium octasulfatodiceriate pentahydrate

Single crystals without Co and Ni have been crystallized by the substitution method in the K₂Ni(SO₄)₂-Ce(SO₄)₂-H₂SO₄-H₂O system using K₂Co(SO₄)₂ · 6H₂O, K₂ (Co,Ni)(SO₄)₂ · 6H₂O, or K₂Ni(SO₄)₂ · 6H₂O as protocrystals. The structure of the single crystals obtained has been established by X-ray diffraction analysis. The crystal structure contains dimer complex anions [Ce₂(μ-SO₄)₂(SO₄)₆]⁸⁻, K⁺ cations, and crystallization water molecules.     

Supramolecular Architecture via Self-Complementary Amide Hydrogen Bonding in [Ag(pia)<Subscript>2</Subscript>](NO<Subscript>3</Subscript>)·H<Subscript>2</Subscript>O: Synthesis,Thermal and Structural Studies

Abstract  

The synthesis, thermal and spectral characterization and crystal structure of silver(I) complex with picolinamide, [Ag(C₆H₆N₂O)₂](NO₃)·H₂O, are reported. The silver(I) atom is chelated by two picolinamide (pia) ligands in approximately square planar geometry. The distortion within the coordination environment is mainly imposed by formation of the chelate rings, but it is also observed in two longer (Ag–O) and two shorter (Ag–N) bond lengths. The compound crystallizes in the triclinic space group P[`1]P\bar{1} with a = 7.1265(2) ?, b = 8.9157(4) ?, c = 12.9527(4) ?, α = 83.934(3)°, β = 86.094(2)°, γ = 67.023(3)° and Z = 2. Cationic complexes are linked through amide–amide hydrogen bonds of ‘head-to-head’ R ₂²(8) motif leading to infinite chains, while nitrate anions and H₂O molecules act only as a cross-link between such four symmetry related cationic chains via hydrogen bonds forming 2D supramolecular double sheets. Therefore, the ‘head-to-head’ amide interactions in [Ag(C₆H₆N₂O)₂](NO₃)·H₂O are robust enough to accommodate the usually disruptive NO₃ ⁻ anion and H₂O molecule and could be regarded as a tool for controlling the assembly of this silver complex.     

Double Salt Formation in the Cu(HCOO)2–Sr(HCOO)2–H2O System

The solubility in the Cu(HCOO)₂–Sr(HCOO)₂–H₂O system has been studied by the method of physico-chemical analysis at 25 and 50 °C. It has been established that two double salts are formed in the system: CuSr₂(HCOO)₆ · H₂O at 25 °C and CuSr(HCOO)₄ · 4 H₂O at 50 °C. The latter salt has not yet been described in the literature. It has been characterized by X-ray powder diffraction and DT and TG analysis. CuSr(HCOO)₄ · 4 H₂O crystallizes in the triclinic system with lattice parameters a = 12.376(6) Å, b = 13.394(4) Å, c = 11.508(6) Å, α = 93.38(3)°, β = 94.01(3)°, γ = 75.04(3)°. Dehydration proceeds in two stages.     

Synthesis and crystal structures of two new complexes [M(OH2)(HDPA)2]·3H2O (M = Mn, Co)

Two new transition metal complexes of [M(OH₂)(HDPA)₂]·3H₂O (M=Mn(1); M=Co(2)) (H₂DPA, 2,6-pyridine-dicarboxylic acid) have been prepared at room temperature from the reaction of MCl₂·6H₂O (M=Mn or Co) and H₂DPA in the mixed solvent of H₂O and EtOH in the presence of piperazine, and were characterized by X-ray analysis, elemental analysis. X-ray analysis reveals that the coordination geometries of Mn²⁺ and Co²⁺ are of octahedron and severely distorted square-based pyramid, respectively. Crystal data: [Mn(OH₂)(HDPA)₂]·3H₂O (1), Mr=459.23, monoclinic, P2(1)/n, a=7.0056(3), b=(23.8125(12), c=10.7444(3) ?, β=99.834(2)°, Z=4, V=1766.28(13) ?³, R ₁=0.0586, wR ₂=0.1448 [I>2σ(I)]; Co(OH₂)(HDPA)₂]·3H₂O (2), Mr=463.22, monoclinic, P2(1)/n, a=7.0014(2), b=23.8346(7), c=10.7212(4) ?, β=99.8540(10)°, Z=4, V=1762.71(10) ?³, R ₁=0.0474, wR ₂=0.1366 [I>2σ(I)].     

Synthesis and Crystal Structure of 2D Supramolecular Compound [Co(phth)(phen) (H<Subscript>2</Subscript>O)<Subscript>3</Subscript>]·H<Subscript>2</Subscript>O

Abstract  

A 2D supramolecular compound [Co(phth)(phen) (H₂O)₃]·H₂O has been synthysized by the reactions of Co(NO₃)₂·6H₂O, 1, 10-phenanthroline(phen) and phthalate acid(H₂phth) in NaOH solution with pH 7.0.The complex has been characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis which shows it belongs the monoclinic space group P2(1)/n, a = 7.571(2) ?, b = 13.737(3) ?, c = 20.015(4) ?, β = 95.56(1)°. V = 2071.9(8) ?³, Mr = 475.31, Dc = 1.524 g/cm⁻³, Z = 4, F(000) = 980, μ(MoKa) = 0.879 mm⁻¹. The final R1 and wR2 are 0.0348 and 0.0711, respectively. The cobalt(II) ion is six-coordinated in a distorted octahedron to form a unit. Every unit is connected by hydrogen bonds forming 1D chain and 2D supramolecular network by π–π stacking interaction between adjoining chains.     

On the (MgxNi1–x)SeO4 · 6 H2O and (MgxCu1–x)SeO4 · 5 H2O mixed crystal formation

Mixed crystals (Mg_xNi_1–x)SeO₄ · 6 H₂O and (Mg_xCu_1–x)SeO₄ · 5 H₂O have been prepared studying the solubility in the MgSeO₄–NiSeO₄–H₂O and MgSeO₄–CuSeO₄–H_2O systems at 25 °C. It has been shown that the monoclinic structure of MgSeO₄ · 6 H₂O is unstable and undergoes a change into tetragonal structure due to the included nickel ions (about 4 at %). The lattice parameters of (Mg_{xNi 1–x})SeO₄ 6 H₂O have been calculated. It has been established that the magnesium ions incorporate isodimorphously in the crystal structure of CuSeO₄ · 5 H₂O which could be an indication of the existence of MgSeO₄ · 5 H₂O isostructural with the triclinic CuSeO₄ 5 H₂O. The distribution coefficients of the salt components between the liquid and solid phases have been calculated.     

Synthesis,characterization and crystal structure of a novel Ni(II) coordination polymer with dipyrido[3,2‐a:2′,3′‐c]phenazine and 4,4′‐oxy(bisbenzoate)

A novel coordination polymer, [Ni(dppz)(oba)(H₂O)]·0.5H₂O (dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine and oba = 4,4′‐oxy(bisbenzoate)) has been synthesized through hydrothermal method and characterized by IR, and single‐crystal X‐ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 23.163(5), b = 18.211(4), c = 14.460(3) Å, α = γ = 90°, β = 100.45(3)°, V = 5998(2) ų, Z = 2. The structure was solved by direct methods and refined to R = 0.0866 (wR₂ = 0.1836). The compound exhibits interesting one‐dimensional chain structures, which are further stacked through π‐π interactions to form supramolecular double chains. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure of Two Nickel Complexes with m-Aminophenol-N,N,O-Triacetic Acid, the Effect of Temperature in the Synthesis

Abstract  

Two nickel coordination compounds with m-aminophenol-N,N,O-triacetic acid (H₃L), [Ni(L)·(H₂O)₃]₂·Ni(H₂O)₆·4.3H₂O (1), and [Ni(L)·H₂O]₂·Ni(H₂O)₆ (2), were obtained under similar reaction conditions but at different synthesis temperature. Single crystal X-ray diffraction analysis reveals that both coordination compounds exhibit discrete dimeric entity structures and contain hexaaquanickel cations acting as counter-ions. Unit cell data for (1): triclinic, space group P-1, a = 7.9977(16), b = 10.475(2), c = 12.952(3) ? and α = 107.36(3), β = 99.66(3), γ = 96.15(3)°; and for (2): monoclinic, space group P2₁/c, a = 13.524(3), b = 8.5703(17), c = 13.820(3) ? and β = 95.25(3)°. In (1), O–H⋯O hydrogen bonds link the complex anions into a dimeric unit. But in (2), the dimeric unit is generated from two Ni centers bridged by two ligands. Extensive hydrogen bond interactions exist in both coordination compounds, and connect the complex anions, hexaaquanickel cations and/or water molecules, resulting in three-dimensional supramolecular structures. The compounds also have been characterized by elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR and UV–Vis spectra.