Hexa­aqua­nickel(II) bis­(hypophosphite)

The structure of hexa­aqua­nickel(II) bis­(hypophosphite), [Ni(H₂O)₆](H₂PO₂)₂, has been determined. The crystals are prismatic. The packing of the Ni and P atoms (not the entire hypophosphite anions) is the same as in the structures of [Co(H₂O)₆](H₂PO₂)₂ and [Co_0.5Ni_0.5(H₂O)₆](H₂PO₂)₂. The Ni^II cations have a pseudo‐face‐centered cubic cell, with cell parameter a 10.216 Å and tetrahedral cavities occupied by P atoms. The Ni^II cation has crystallographically imposed twofold symmetry and has an octahedral coordination sphere consisting of six water O atoms, two of which also lie on the twofold axis. The planes of oppositely coordinated water mol­ecules are in a cross conformation. The geometry of the hypophosphite anion is close to point symmetry mm2. The hypophosphite anions are hydrogen bonded to the coordinated water molecules.     

A urea complex of copper(II) hypophosphite at 293, 100 and 15 K

The crystal structure of poly­[copper(II)‐di‐μ‐hypophosphito‐μ‐urea], [Cu(H₂PO₂)₂(CH₄N₂O)]_n, has been determined at 293, 100 and 15 K. The geometry of the hypophosphite anion is very close to ideal, with point symmetry mm2. Each Cu atom lies on an inversion centre and is coordinated to six O atoms from four hypophosphite anions and two urea mol­ecules, forming a tetragonal bipyramid. The unique urea molecule lies on a twofold axis. Each hypophosphite anion in the structure is coordinated to two Cu atoms. The hypophosphite anions, urea mol­ecules and Cu^II cations form polymeric ribbons. The Cu^II cations in the ribbon are linked together by two hypophos­phite anions and a urea mol­ecule, which is coordinated to Cu via an O atom. The ribbons are linked to each other by N—­H?O hydrogen bonds and form polymeric layers.     

Two 2,5‐bis(2‐pyridinyl)‐1,3,4‐oxa­diazo­le–metal complexes (M = Cu and Ni)

The reaction of the diazine ligand 3,5‐bis(2‐pyridinyl)‐1,3,4‐oxa­diazole (pod, C₁₂H₈N₄O), with Cu(CF₃SO₃)₂ or Ni(ClO₄)₂ afforded the title complexes di­aqua­bis­[3,5‐bis(2‐pyridinyl)‐1,3,4‐oxa­diazole‐N²,N³]copper(II) bis­(tri­fluoro­methane­sul­fon­ate), [Cu(pod)₂(H₂O)₂](CF₃SO₃)₂, and di­aqua­bis­[3,5‐bis(2‐pyridinyl)‐1,3,4‐oxa­diazo­le‐N²,N³]­nickel(II) diperchlorate, [Ni(pod)₂(H₂O)₂](ClO₄)₂. Both complexes present a crystallographically centrosymmetric mononuclear cation structure which consists of a six‐coordinated Cu^II or Ni^II ion with two pod mol­ecules acting as bidentate ligands and two axially coordinated water mol­ecules.     

Cobalt(II) and nickel(II) complexes of quinoline‐2‐carboxyl­ate

The title complexes, trans‐di­aqua­bis­(quinoline‐2‐carboxyl­ato‐κ²N,O)­cobalt(II)–water–methanol (1/2/2), [Co(C₁₀H₆NO₂)₂(H₂O)₂]·2CH₄O·2H₂O, and trans‐di­aqua­bis­(quinoline‐2‐car­box­yl­ato‐κ²N,O)­nickel(II)–water–methanol (1/2/2), [Ni(C₁₀H₆NO₂)₂(H₂O)₂]·2CH₄O·2H₂O, are isomorphous and contain Co^II and Ni^II ions at centers of inversion. Both complexes have the same distorted octahedral coordination geometry, and each metal ion is coordinated by two quinoline N atoms, two carboxyl­ate O atoms and two water O atoms. The quinoline‐2‐carboxyl­ate ligands lie in trans positions with respect to one another, forming the equatorial plane, with the two water ligands occupying the axial positions. The complex mol­ecules are linked together by hydrogen bonding involving a series of ring patterns which include the uncoordinated water and methanol mol­ecules.     

Hydrogen bonding and π–π stacking in methyl­aminium 4′,7‐dihydroxy­isoflavone‐3′‐sulfonate dihydrate and hexa­aqua­iron(II) bis­(4′,7‐diethoxy­isoflavone‐3′‐sulfonate) tetra­hydrate

In methyl­aminium 4′,7‐dihydroxy­isoflavone‐3′‐sulfonate dihydrate, CH₆N⁺·C₁₅H₉O₇S⁻·2H₂O, 11 hydrogen bonds exist between the methyl­aminium cations, the iso­flavone‐3′‐sulfonate anions and the solvent water mol­ecules. In hexa­aqua­iron(II) bis­(4′,7‐diethoxy­isoflavone‐3′‐sulfonate) tetra­hydrate, [Fe(H₂O)₆](C₁₉H₁₇O₇S)₂·4H₂O, 12 hydrogen bonds exist between the centrosymmetric [Fe(H₂O)₆]²⁺ cation, the isoflavone‐3′‐sulfonate anions and the solvent water mol­ecules. Additional π–π stacking inter­actions generate three‐dimensional supramolecular structures in both compounds.     

Di­aqua­bis­(di­methyl sulfoxide)­bis(3,5‐di­nitro­benzoato)­zinc(II) and the synthesis of the Cu,Ni and Co analogs

In order to model processes of chemisorption in organic salts formed between di­nitro­benzoic acids (DNBH) and secondary amines (R₂NH), a series of compounds of composition [M^II(3,5‐DNB)₂(DMSO)₂(H₂O)₂] (where M^II is Zn, Cu, Ni or Co, 3,5‐DNB is the 3,5‐di­nitro­benzoate ion, and DMSO is di­methyl sulfoxide) have been prepared. In di­aqua­bis­(di­methyl sulf­oxide)­bis(3,5‐DNB)­zinc(II), [Zn(C₇H₃N₂O₆)₂(C₂H₆OS)₂(H₂O)₂], the 3,5‐DNB ions and mol­ecules of DMSO are monodentate ligands that are coordinated to the Zn atom through their O atoms. These ligands, together with two mol­ecules of water, form a slightly distorted octahedral coordination environment for the Zn atom, which lies on a center of symmetry.     

X-ray powder structure of a new two-dimensional nickel(II) coordination polymer with pyrazine-2,3,5,6-tetracarboxylic acid

The new nickel(II) coordination polymer poly­[di­aqua­nickel(II)-μ-(pyrazine-2,3,5,6-tetra­carboxyl­ato)-tetra­aqua­nickel(II)], {[{Ni(C₈N₂O₈)(H₂O)₂}Ni(H₂O)₄]}_n, has been synthesized and characterized both spectroscopically and crystallographically, by X-ray powder diffraction analysis. In this two-dimensional coordination polymer, Ni^II ions are bridged by pyrazine-2,3,5,6-tetra­carboxyl­ic acid, coordinating in a bis-bidentate manner, so forming one-dimensional polymeric chains. The chains are linked by a second Ni^II ion, via an O atom of the coordinated carboxyl­ate group, resulting in the formation of a two-dimensional layer-like polymer. The remaining coordination sites of the two independent octahedral Ni^II ions are occupied by water mol­ecules. The layers are connected via hydrogen bonds involving all six coordinated water mol­ecules.     

Di‐μ‐sulfido‐bis[diaqua(18‐crown‐6)­barium(II)]–saccharin (1/2)

The mol­ecule of the title compound {systematic name: di‐μ‐sulfido‐bis[di­aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octade­cane‐κ⁶O)barium(II)] bis­[1,2‐benzisothiazol‐3(2H)‐one 1,1‐dioxide]}, [Ba₂S₂(C₁₂H₂₄O₆)₂(H₂O)₄](C₇H₅NO₃S)₂, lies on an inversion centre. The Ba^II atom encapsulated by the 18‐crown‐6 ring is coordinated by the six O atoms of the crown, two water O atoms and two bridging S atoms. The four‐membered ring composed of the Ba^II atoms and the bridging S atoms makes a dihedral angle of 67.1 (1)° with the crown‐ether ring. The aromatic ring system of the saccharin moiety is essentially planar. The packing is built up from layers of the mol­ecules and is stabilized by three intermolecular O—H?O hydrogen bonds.     

The first X‐ray structure of a hexa­ammine­cobalt(III) salt with two different complex chloro­cadmium anions: synthesis,characterization and crystal structure of [Co(NH3)6]4[CdCl6][CdCl4(SCN)(H2O)]2Cl2·2H2O

In the title complex salt, tetra­kis[hexa­ammine­cobalt(III)] hexa­chloro­cadmate(II) bis­[aqua­tetra­chloro­thio­cyanato­cad­mate(II)] dichloride dihydrate, the discrete ions, i.e. [Co(NH₃)₆]³⁺, Cl⁻, [CdCl₆]⁴⁻ (located on an inversion centre) and [CdCl₄(SCN)(H₂O)]³⁻, together with cocrystallized water mol­ecules, are assembled by means of a network of hydrogen‐bonding inter­actions. This is the first X‐ray structure determination of a hexa­amminecobalt(III) salt with two different complex chloro­cadmium anions.     

Diaquabis(1,3‐propanediamine‐κ2N,N′)nickel(II) bis(sulfanilate)

The title compound, [Ni(C₃H₁₀N₂)₂(H₂O)₂](C₆H₆NO₃S)₂, contains alternating layers of sulfanilate anions and di­aqua­bis(1,3‐propane­di­amine)­nickel(II) cations. The Ni atom lies on an inversion centre and is hexacoordinated by the 1,3‐propane­di­amine ligands, which function as N,N′‐bidentate ligands, and the water mol­ecules, which are in a trans arrangement. The sulfanilate anions are arranged in layers, with the sulfonate and amine groups directed towards opposite sides of the layer. The structure is stabilized by a network of hydrogen bonding between the O and N atoms of the sulfanilate anions, the water mol­ecules, and the N atoms of the 1,3‐propane­di­amine ligands.     

Hydrate isomerism in [Cu(en)2(H2O)1.935]2[Fe(CN)6]·4H2O

The title compound, bis[di­aqua­bis­(ethyl­enedi­amine‐κ²N,N′)copper(II)­] hexa­cyano­iron(II) tetrahydrate, [Cu(C₂H₈N₂)₂(H₂O)_1.935]₂[Fe(CN)₆]·4H₂O, was crystallized from an aqueous reaction mixture initially containing CuSO₄, K₃[Fe(CN)₆] and ethyl­enedi­amine (en) in a 3:2:6 molar ratio. Its structure is ionic and is built up of two crystallographically different cations, viz. [Cu(en)₂(H₂O)₂]²⁺ and [Cu(en)₂(H₂O)_1.87]²⁺, there being a deficiency of aqua ligands in the latter, [Fe(CN)₆]⁴⁻ anions and disordered solvent water mol­ecules. All the metal atoms lie on centres of inversion. The Cu atom is octahedrally coordinated by two chelate‐bonded en mol­ecules [mean Cu—N = 2.016 (2) Å] in the equatorial plane, and by axial aqua ligands, showing very long distances due to the Jahn–Teller effect [mean Cu—O = 2.611 (2) Å]. In one of the cations, significant underoccupation of the O‐atom site is observed, correlated with the appearance of a non‐coordinated water mol­ecule. This is interpreted as the partial contribution of a hydrate isomer. The [Fe(CN)₆]⁴⁻ anions form quite regular octahedra, with a mean Fe—C distance of 1.913 (2) Å. The dominant intermolecular interactions are cation–anion O—H⋯N hydrogen bonds and these inter­actions form layers parallel to (001).     

Tris(ethyl­ene­diamine)­nickel(II) bis­[2‐cyano‐2‐(oxidoimino)­acetamidato]­nickelate(II) monohydrate

The title compound, [Ni(C₂H₈N₂)₃][Ni(C₃HN₃O₂)₂]·H₂O, appears to be a modular associate consisting of two complex counter‐ions, containing bivalent nickel as the central atom in both cases, and a solvent water mol­ecule. The Ni^II ion in the complex cation lies on the C₂ crystallographic axis. Its coordination environment is formed by six N atoms of three ethyl­ene­diamine (en) mol­ecules, representing a distorted octa­hedral geometry. The Ni^II ion in the complex anion occupies a position at the center of inversion. It exhibits a distorted square‐planar coordination geometry formed by four N atoms belonging to the deprotonated oxidoimine and amide groups of the two doubly charged 2‐cyano‐2‐(oxidoimino)acetamidate anions, situated in trans positions with respect to each other. In the crystal packing, the complex anions are linked by water mol­ecules via hydrogen bonds between the amide O atoms and water H atoms, forming chains translated along the a direction. The [Ni(en)₃]²⁺ cations fill empty spaces between the translational chains, connecting them by hydrogen bonds between the oxime and amide O atoms of the anions and the amine H atoms of the cations, forming layers along the ac plane. The water mol­ecules provide connection between layers through N atoms of the cations, thus forming a three‐dimensional modular structure.     

(μ‐Oxalato‐O1,O2:O1′,O2′)bis[aqua(diethyl­enetri­amine)nickel(II)] bis(hexafluorophosphate) dihydrate

The title compound, [Ni₂(C₂O₄)(C₄H₁₃N₃)₂(H₂O)₂](PF₆)₂·‐2H₂O, contains a dinuclear oxalato‐bridged nickel(II) complex cation. The structure determination reveals the presence of a centrosymmetric binuclear complex where the oxalate ligand is coordinated in a bis­‐bidentate mode to the Ni atoms. The distorted octahedral environment of each Ni atom is completed by the three N atoms of the diethyl­enetri­amine ligand in a fac arrangement and by one O atom from a water mol­ecule. PF₆^? acts as counter‐anion. A two‐dimensional network of hydrogen bonds links the cations and anions and stabilizes the structure.     

Two new [Ni(tren)2]2+ complexes: [Ni(tren)2]Cl2 and [Ni(tren)2]WS4

Both title compounds, bis­[tris(2‐amino­ethyl)­amine]­nickel(II) dichloride, [Ni(tren)₂]Cl₂, (I), and bis­[tris(2‐amino­ethyl)­amine]­nickel(II) tetra­thio­tungstate, [Ni(tren)₂]WS₄, (II), contain the [Ni(tren)₂]²⁺ cation [tren is tris(2‐amino­ethyl)­amine, C₆H₁₈N₄]. The tren mol­ecule acts as a tridentate ligand around the central Ni atom, with the remaining primary amine group not bound to the central atom. In (I), Ni²⁺ is located on a centre of inversion surrounded by one crystallographically independent tren mol­ecule. In the [Ni(tren)₂]²⁺ cation of (II), the Ni atom is bound to two crystallographically independent tren mol­ecules. The Ni atoms in the [Ni(tren)₂]²⁺ complexes are in a distorted octahedral environment consisting of six N atoms from the chelating tren mol­ecules. The counter‐ions are chloride anions in (I) and the tetrahedral [WS₄]^2? anion in (II). Hydro­gen bonding is observed in both compounds.     

Bis­(acesulfamato)­tetra­aqua­cobalt(II)

The crystal structure of the first acesulfame–metal complex, namely tetra­aqua­bis­[6‐methyl‐1,2,3‐oxa­thia­zin‐4(3H)‐onato 2,2‐dioxide‐κN]­cobalt(II), [Co(C₄H₄NO₄S)₂(H₂O)₄], is re­ported. The Co^II ion resides on a twofold axis and is coordinated by four aqua ligands defining the basal plane and by two monodentate acesulfamate ligands, via their ring N atoms, in the axial positions. Two intra‐ and three intermolecular hydrogen‐bonding interactions stabilize the crystal structure and form an infinite three‐dimensional lattice.     

Pt2II and Pt2III dimers containing a Pt2(2,2′‐bipyridine)2(μ‐N,N‐dimethyl­guanidinato)2 unit

The syntheses and crystal structures of the title Pt₂^II and Pt₂^III dimers doubly bridged with N,N‐dimethyl­guanidinate ligands, namely bis­(μ‐N,N‐dimethyl­guanidinato)bis­[(2,2′‐bipyridine)platinum(II)](Pt—Pt) bis­(hexa­fluoro­phosphate) acetonitrile disolvate, [Pt₂^II(C₃H₈N₃)₂(C₁₀H₈N₂)₂](PF₆)₂·2CH₃CN, (I), and guanidinium bis­(μ‐N,N‐dimethyl­guanidinato)bis­[(2,2′‐bipyridine)sulfatoplatinum(III)](Pt—Pt) bis­(hexa­fluoro­phosphate) nitrate hexa­hydrate, (C₃H₁₀N₃)[Pt^III₂(C₃H₈N₃)₂(SO₄)₂(C₁₀H₈N₂)₂]NO₃·6H₂O, (II), are reported. The oxidation of the Pt₂^II dimer into the Pt₂^III dimer results in a marked shortening of the Pt—Pt distance from 2.8512 (6) to 2.5656 (4) Å. The change is mainly compensated for by the change in the dihedral angle between the two Pt coordination planes upon oxidation, from 21.9 (2) to 16.9 (3)°. We attribute the relatively strong one‐dimensional stack of dimers achieved in the Pt₂^II compound in part to the strong Pt^II⋯C(bpy) associations (bpy is 2,2′‐bipyridine) in the crystal structure [Pt⋯C = 3.416 (10) and 3.361 (12) Å].     

Diaquabis(propane-1,2-diamine-N,N′)nickel(II) bis(p-toluenesulfonate)

The crystal structure of the title compound, [Ni(C₃H₁₀N₂)₂(H₂O)₂](C₇H₇O₃S)₂ or [Ni(H₂O)₂{NH₂CH₂CH­(NH₂)CH₃}₂](CH₃C₆H₄SO₃)₂, exhibits a layered structure in which the complex cations and the p-toluene­sulfonate anions form alternating layers. The central Ni^II atom of the cation resides on a crystallographic inversion centre and has a slightly distorted octahedral coordination composed of the water ligands bonding through oxy­gen in a trans arrangement and the N,N′-bidentate propane­di­amine ligands. The p-toluene­sulfonate anions are arranged with the sulfonate groups turned alternately towards opposite sides of the layers. The structure of the layers is stabilized by a network of hydrogen bonds between the sulfonate O atoms, water mol­ecules and the propane­di­amine N atoms.     

Tetrakis[(4‐aminopyridinio)acetato‐κO]diaquamanganese(II) diper­chlorate

In the centrosymmetric title complex, [Mn(C₇H₈N₂O₂)₄(H₂O)₂](ClO₄)₂, the Mn^II ion is in an octahedral environment, with the equatorial plane being defined by the O atoms of four monodentate carboxyl­ate groups, and the octahedron being completed by two trans‐coordinated water mol­ecules. There are intramolecular hydrogen bonds between the coordinated water mol­ecules and the non‐coordinated O atoms of the carboxyl­ate groups. Hydrogen bonds between the amino groups and the carboxyl­ate groups of neighbouring mol­ecules generate a layered hydrogen‐bonded network.     

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.     

Hexa­aqua­nickel diorotate(1–) dihydrate at 150 K

In hexa­aqua­nickel bis(2,6‐di­oxo‐1,2,3,6‐tetrahydro­pyrimidine‐4‐carboxyl­ate) dihydrate, [Ni(H₂O)₆](C₅H₃N₂O₄)₂·2H₂O, the nickel cation is coordinated by six aqua ligands and only associated with the two orotate ions through hydrogen bonds. The structure is isotypic with the magnesium and zinc analogues. The metal cation sits on a crystallographic center of inversion that relates the water mol­ecules and the organic anions. The orotate moieties form an unbonded one‐dimensional chain mediated by a hydrogen‐bonded self‐recognition interaction. The hexa­aqua­nickel complex molecules bridge these chains laterally, acting as molecular clamps that bring neighboring layers nearer than expected. As a result of this three‐dimensional arrangement, a short contact of 3.166 (5) Å is observed between two C atoms of two adjacent ribbons.