PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (763829)

Clipboard (0)
None

Related Articles

1.  Adenin-1-ium hydrogen isophthalate di­methyl­formamide monosolvate 
In the title proton-transfer organic salt, C5H6.3N5 +·C8H4.7O4 −·C3H7NO, the adeninium moiety is protonated at the N atom in the 1-position of the 6-amino-7H-purin-1-ium (adeninium) cation. In the solid state, the second acidic proton of isophthalic acid is partially transferred to the imidazole N atom of the adeninium cation [refined O—H versus N—H ratio = 0.70 (11):0.30 (11)]. Through the partially transferred proton, the adeninium cation is strongly hydrogen bonded (N—H⋯O/O—H⋯N) to the isophthalate anion. This strong inter­action is assisted by another N—H⋯O hydrogen bond originating from the adeninium NH2 group towards the isophthalate keto O atom, with an R 2 2(8) graph-set motif. This arrangement is linked via N—H⋯O hydrogen bonds to the O atoms of the carboxyl­ate group of an isophthalate anion. Together, these hydrogen bonds lead to the formation criss-cross zigzag isophthalate⋯adeninium chains lying parallel to (501) and (50-1). The adeninium cations and the isophthalate anions are arranged in infinite π stacks that extend along the c-axis direction [inter­planar distance = 3.305 (3) Å]. Mol­ecules are inclined with respect to this direction and within the stacks they are offset by ca. half a mol­ecule each. Combination of the N—H⋯O and O—H⋯N hydrogen bonds with the π–π inter­actions forms infinitely stacked isophthalate⋯adeninium chains, thus leading to a two-dimensional supra­molecular structure with parallel inter­digitating layers formed by the π stacked isophthalate⋯adeninium chains. The DMF mol­ecules of crystallization are bonded to the adeninium cations through strong N—H⋯O hydrogen bonds and project into the lattice space in between the anions and cations. There are also C—H⋯O hydrogen bonds present which, combined with the other inter­actions, form a three-dimensional network. The crystal under investigation was found to be split and was handled as if non-merohedrally twinned.
doi:10.1107/S1600536813034971
PMCID: PMC3998323  PMID: 24764884
2.  Crystal structure of [Y6(μ6-O)(μ3-OH)8(H2O)24]I8·8H2O 
In the crystal structure of a hexa­nuclear Y3+ compound, the six Y3+ cations are arranged octa­hedrally around an μ6-O atom at the centre of the cationic complex. Each of the eight faces of the Y6 octa­hedron is capped by an μ3-OH group in the form of a distorted cube. The proximity of the cationic complexes and lattice water mol­ecules leads to the formation of a three-dimensional hydrogen-bonded network of medium strength.
The crystal structure of the title compound {systematic name: octa-μ3-hydroxido-μ6-oxido-hexa­kis­[tetra­aqua­yttrium(III)] octa­iodide octa­hydrate}, is characterized by the presence of the centrosymmetric mol­ecular entity [Y6(μ6-O)(μ3-OH)8(H2O)24]8+, in which the six Y3+ cations are arranged octa­hedrally around a μ6-O atom at the centre of the cationic complex. Each of the eight faces of the Y6 octa­hedron is capped by an μ3-OH group in the form of a distorted cube. In the hexa­nuclear entity, the Y3+ cations are coordinated by the central μ6-O atom, the O atoms of four μ3-OH and of four water mol­ecules. The resulting coordination sphere of the metal ions is a capped square-anti­prism. The crystal packing is quite similar to that of the ortho­rhom­bic [Ln 6(μ6-O)(μ3-OH)8(H2O)24]I8·8H2O structures with Ln = La—Nd, Eu—Tb, Dy, except that the title compound exhibits a slight monoclinic distortion. The proximity of the cationic complexes and the lattice water mol­ecules leads to the formation of a three-dimensional hydrogen-bonded network of medium strength.
doi:10.1107/S1600536814025434
PMCID: PMC4257455  PMID: 25552996
crystal structure; hexa­nuclear compounds; lanthanide compound; three-dimensional hydrogen-bonded network
3.  The CouPSTU and TarPQM Transporters in Rhodopseudomonas palustris: Redundant, Promiscuous Uptake Systems for Lignin-Derived Aromatic Substrates 
PLoS ONE  2013;8(3):e59844.
The biodegradation of lignin, one of the most abundant carbon compounds on Earth, has important biotechnological applications in the derivation of useful products from lignocellulosic wastes. The purple photosynthetic bacterium Rhodopseudomonas palustris is able to grow photoheterotrophically under anaerobic conditions on a range of phenylpropeneoid lignin monomers, including coumarate, ferulate, caffeate, and cinnamate. RPA1789 (CouP) is the periplasmic binding-protein component of an ABC system (CouPSTU; RPA1789, RPA1791–1793), which has previously been implicated in the active transport of this class of aromatic substrate. Here, we show using both intrinsic tryptophan fluorescence and isothermal titration calorimetry that CouP binds a range of phenylpropeneoid ligands with Kd values in the nanomolar range. The crystal structure of CouP with ferulate as the bound ligand shows H-bond interactions between the 4-OH group of the aromatic ring with His309 and Gln305. H-bonds are also made between the carboxyl group on the ferulate side chain and Arg197, Ser222, and Thr102. An additional transport system (TarPQM; RPA1782–1784), a member of the tripartite ATP-independent periplasmic (TRAP) transporter family, is encoded at the same locus as rpa1789 and several other genes involved in coumarate metabolism. We show that the periplasmic binding-protein of this system (TarP; RPA1782) also binds coumarate, ferulate, caffeate, and cinnamate with nanomolar Kd values. Thus, we conclude that R. palustris uses two redundant but energetically distinct primary and secondary transporters that both employ high-affinity periplasmic binding-proteins to maximise the uptake of lignin-derived aromatic substrates from the environment. Our data provide a detailed thermodynamic and structural basis for understanding the interaction of lignin-derived aromatic substrates with proteins and will be of use in the further exploitation of the flexible metabolism of R. palustris for anaerobic aromatic biotransformations.
doi:10.1371/journal.pone.0059844
PMCID: PMC3610893  PMID: 23555803
4.  Hexakis(1H-imidazole-κN 3)mangan­ese(II) triaqua­tris(1H-imidazole-κN 3)manganese(II) bis­(naphthalene-1,4-dicarboxyl­ate) 
In the crystal structure of the title compound, [Mn(C3H4N2)6][Mn(C3H4N2)3(H2O)3](C12H6O4)2, there are uncoordinated naphthalene­dicarboxyl­ate dianions and two kinds of MnII complex cations, both assuming a distorted octa­hedral geometry. One MnII cation is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other MnII cation is located on a twofold rotation axis and is coordinated by three water mol­ecules and three imidazole units. The naphthalene­dicarboxyl­ate dianions are linked to both MnII complex cations via O—H⋯O and N—H⋯O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure.
doi:10.1107/S1600536808011677
PMCID: PMC2961172  PMID: 21202252
5.  Hexakis(1H-imidazole-κN 3)nickel(II) bis­(2,4-dibromo-6-formyl­phenolate) N,N-dimethyl­formamide disolvate 
In the cation of the title compound, [Ni(C3H4N2)6](C7H3Br2O2)2·2C3H7NO, the NiII ion lies on an inversion center and is coordinated in a slightly distorted octa­hedral environment by six N atoms from six imidazole ligands. In the crystal structure, cations, anions and solvent mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds into one-dimensional chains along [010]. In addition, the crystal structure is stabilized by weak C—H⋯O and C—H⋯N hydrogen bonds.
doi:10.1107/S1600536808018989
PMCID: PMC2961690  PMID: 21202814
6.  Hexakis(1H-imidazole-κN 3)cobalt(III) tris­(hexa­fluoridophosphate) hexa­hydrate 
In the crystal structure of the title compound, [Co(C3H4N2)6](PF6)3·6H2O, the CoIII atom lies on a special position with site-symmetry and the P atom is located on a special position with site symmetry . The CoIII atom has an almost ideal octa­hedral coordination formed by the N atoms of six imidazole ligands. The water mol­ecules form hydrogen-bonded helical chains propagating in [001] by O—H⋯O inter­actions with a distance of 2.913 (2) Å. They simultaneously inter­act as hydrogen-bond acceptors and donors with the cations and anions, respectively, resulting in the formation of a three-dimensional assembly. Weak C—H⋯F inter­actions further stabilize the crystal structure.
doi:10.1107/S160053680903863X
PMCID: PMC2970253  PMID: 21577770
7.  Hexakis(1H-imidazole-κN 3)nickel(II) triaqua­tris(1H-imidazole-κN 3)nickel(II) bis­(naphthalene-1,4-dicarboxyl­ate) 
The crystal structure of the title compound, [Ni(C3H4N2)6][Ni(C3H4N2)3(H2O)3](C12H6O4)2, contains uncoordinated naphthalene­dicarboxyl­ate dianions and two kinds of NiII complex cations, both assuming distorted octa­hedral geometries. One NiII ion is located on an inversion center and is coordinated by six imidazole mol­ecules, while the other NiII ion is located on a twofold rotation axis and is coordinated by three water mol­ecules and three imidazole mol­ecules in a mer-NiN3O3 arrangement. The naphthalene­dicarboxyl­ate dianion links both NiII complex cations via O—H⋯O and N—H⋯O hydrogen bonding, but no π–π stacking is observed between aromatic rings in the crystal structure. One imidazole ligand is equally disordered over two sites about a twofold rotation axis; one N atom and one water O atom have site symmetry 2.
doi:10.1107/S1600536808024215
PMCID: PMC2960677  PMID: 21201574
8.  Crystal structure of di-μ-hydroxido-bis­[aqua­(1,10-phenanthroline-κ2 N,N′)copper(II)] naphthalene-2,6-di­carboxyl­ate hexa­hydrate 
The cations and anions of the title compound are organized through π–π stacking between the aromatic rings of the 1,10-phenanthroline and the naphthalene-2,6-carboxyl­ate into a two-dimensional structure. The extensive O—H⋯H hydrogen bonds further connect the cations, anions and lattice water mol­ecules into a three-dimensional network.
In the title compound, [Cu2(OH)2(C12H8N2)2(H2O)2](C12H6O4)·6H2O, the two hydroxide groups bridge the two CuII cations, forming a centrosymmetric binuclear complex cation, in which the CuII cation is coordinated by a 1,10-phenanthroline (phen) mol­ecule, one water mol­ecule and two bridging hydroxide O atoms in a distorted N2O3 square-pyramidal coordination geometry. The naphthalene-2,6-di­carboxyl­ate anion is also located on an inversion centre. In the crystal, O—H⋯O hydrogen bonds link the cations, anions and lattice water mol­ecules into a three-dimensional supra­molecular architecture. Extensive π–π stacking is observed between the parallel or nearly parallel aromatic rings of adjacent phen ligands and naphthalenedi­carboxyl­ate anions, the centroid-to-centroid distances ranging from 3.4990 (16) to 3.8895 (16) Å.
doi:10.1107/S2056989015004338
PMCID: PMC4438840  PMID: 26029390
crystal structure; binuclear copper(II) complex; crystal engineering; hydrogen bonding; π–π stacking
9.  Hexa­kis­(μ3-1-methyl­thio­urea-κ3 S:S:S)hexa­kis­[iodidocopper(I)] 
The title compound, [Cu6I6(C2H6N2S)6], was obtained from the reaction of copper(I) iodide with N-methyl­thio­urea (Metu) in equimolar amounts in acetonitile. The complex consists of two six-membered trinuclear Cu3S3I3 cores that combine through triply bridging Metu, forming a hexa­nuclear core which has -3 symmetry. The CuII atom is coordinated by three S atoms of Metu and one iodide ion in a distorted tetra­hedral geometry. The crystal structure is stabilized by N—H⋯I hydrogen bonds and cuprophilic inter­actions [Cu⋯Cu = 3.0264 (9) Å].
doi:10.1107/S1600536812043437
PMCID: PMC3515146  PMID: 23284373
10.  Hexa­kis­(N,N′-dimethyl­thio­urea-κS)nickel(II) nitrate 
The title complex salt, [Ni(C3H8N2S)6](NO3)2, consists of an [Ni(Dmtu)6]2+ (Dmtu is N,N′-dimethyl­thio­urea) dication and two nitrate counter-anions. The NiII atom (site symmetry ) is coordinated by the S atoms of six Dmtu ligands within a slightly distorted octa­hedral environment. The crystal structure is characterized by weak intra­molecular N—H⋯S inter­actions and by inter­molecular N—H⋯O hydrogen bonds involving the nitrate anion (site symmetry 3.). These inter­molecular inter­actions lead to the formation of two-dimensional networks lying parallel to the ab plane. The networks are linked via non-classical inter­molecular C—H⋯O hydrogen bonds, forming a three-dimensional arrangement.
doi:10.1107/S1600536810040031
PMCID: PMC3009254  PMID: 21588829
11.  2,5-Bis[2-({bis­[3-(dimethyl­aza­nium­yl)prop­yl]aza­nium­yl}meth­yl)phen­yl]-1,3,4-oxadiazole hexa­kis­(perchlorate) sesquihydrate 
In the title hydrated salt, C36H66N8O6+·6ClO4 −·1.5H2O, the asymmetric unit consists of a hexa­protonated [H6 L]6+ cation, five perchlorate anions in general positions, two on twofold rotation axes (one of which is disordered), and two water mol­ecules of crystallization in general positions, one of them disordered around a twofold crystallographic axis. In the [H6 L]6+ cation, two strong intra­molecular N—H⋯N hydrogen bonds occur, involving the N atoms of the oxadiazole ring as acceptors and the closest NH+ groups of each dipropyl­enetriamine unit. In the crystal, the [H6 L]6+ cations form channels along the a-axis direction, in which the perchlorate counter-ions and the water mol­ecules are lodged. The crystal packing features a network of N—H⋯O and O—H⋯O hydrogen bonds involving the NH+ groups of the [H6 L]6+ cation, the perchlorate anions and the water mol­ecules.
doi:10.1107/S1600536812047484
PMCID: PMC3589030  PMID: 23476266
12.  A dimer of bis­(N-heterocyclic carbene)rhodium(I) centres spanned by a dibenzo-18-crown-6 bridge from synchrotron radiation 
The compound (μ-3,3′,3′′,3′′′-{[2,5,8,15,18,21-hexa­oxatricyclo­[20.4.0.09,14]hexa­cosa-1(22),9,11,13,23,25-hexa­ene-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl))bis­[(η4-cyclo­octa-1,4-diene)rhodium(I)] bis­(hexa­fluoridophosphate) acetonitrile sesquisolvate dihydrate, [Rh2(C8H12)2(C40H42N8O6)](PF6)2·1.5CH3CN·2H2O, crystallized from acetonitrile under an atmosphere of diethyl ether. In the crystal structure, the complex cation exhibits two square-planar RhI centres, each bound by a cyclo­octa­diene (COD) ligand and by two adjacent imidazolyl­idene N-heterocyclic carbene (NHC) donors from the same phen­oxy ring of the {[dibenzo-18-crown-6-11,12,24,25-tetra­yl]tetra­kis­(methyl­ene)}tetra­kis­(1-methyl-1H-imidazol-2-yl) (L) ligand. The dibenzo-crown ether bridge of L spans the Rh centres and forms hydrogen bonds with water mol­ecules. One water mol­ecule with half occupancy bridges adjacent macrocycles in the lattice. Another water with full occupancy forms weak hydrogen bonds to the crown ether O atoms and is, in turn, part hydrogen bonded by a lattice water with half occupancy. The latter water is within hydrogen-bonding distance of a fourth water also with partial occupancy. The result of these inter­actions is the formation of a layer in the ab plane. Two PF6 − ions, one of which is twofold disordered, and one ordered and one twofold disordered (with 0.5 occupancy) lattice acetonitrile mol­ecules complete the crystal structure.
doi:10.1107/S160053681204901X
PMCID: PMC3588264  PMID: 23476343
13.  3,6,9,16,19,22-Hexaazatricyclo-[22.2.2.211, 14]triaconta-1(27),11 (30),-12,14(29),24(28),25-hexaene hexakis(p-toluenesulfonate) dihydrate 
In the title compound, C24H44N66+·6C7H7O3S−·2H2O, the macrocycle crystallizes in its hexaprotonated form, accompanied by six p-toluenesulfonate ions and two water molecules, and lies on an inversion center. The three independent p-toluenesulfonate anions and their inversion equivalents at (1 − x, 1 − y, 1 − z) are linked to the macrocyclic cation through N–H⋯O hydrogen bonds. Of these, two p-toluenesulfonate ions are located on opposite sides of the macrocyclic plane and are linked to bridgehead N atoms via N–H⋯O hydrogen bonds. The remaining four p-toluenesulfonate ions bridge two adjacent macrocyclic cationic units through N–H⋯O hydrogen bonding involving other N atoms, forming a chain along the a axis. The water molecules, which could not be located and may be disordered, do not interact with the macrocycle; however, they form hydrogen bonds with anions.
doi:10.1107/S1600536809035648
PMCID: PMC2822386  PMID: 20165564
single-crystal X-ray study; T = 90 K; mean σ(C–C) = 0.008 Å; H-atom completeness 96%; R factor = 0.072; wR factor = 0.156; data-to-parameter ratio = 16.2
14.  3,6,9,16,19,22-Hexaaza­tricyclo­[22.2.2.211,14]­triaconta-1(27),11 (30),12,14(29),24(28),25-hexa­ene hexa­kis(p-toluene­sulfonate) dihydrate 
In the title compound, C24H44N6 6+·6C7H7O3S−·2H2O, the macrocycle crystallizes in its hexa­protonated form, accompanied by six p-toluene­sulfonate ions and two water mol­ecules, and lies on an inversion center. The three independent p-toluene­sulfonate anions and their inversion equivalents at (1 − x, 1 − y, 1 − z) are linked to the macrocyclic cation through N—H⋯O hydrogen bonds. Of these, two p-toluene­sulfonate ions are located on opposite sides of the macrocyclic plane and are linked to bridgehead N atoms via N—H⋯O hydrogen bonds. The remaining four p-toluene­sulfonate ions bridge two adjacent macrocyclic cationic units through N—H⋯O hydrogen bonding involving other N atoms, forming a chain along the a axis. The water mol­ecules, which could not be located and may be disordered, do not inter­act with the macrocycle; however, they form hydrogen bonds with anions.
doi:10.1107/S1600536809035648
PMCID: PMC2822386  PMID: 20165564
15.  Hexakis(N,N-dimethyl­formamide-κO)cobalt(II) bis­(perchlorate) 
The asymmetric unit of the title complex, [Co(DMF)6](ClO4)2 (DMF = N,N-dimethyl­formamide, C3H7NO), consists of two half complex cations with the Co2+ metal ions located on centers of inversion and two perchlorate anions. In the crystal packing, each Co2+ ion is coordinated by six mol­ecules of DMF in a slightly distorted octa­hedral geometry. The crystal structure is mainly stabilized by coordinative, ionic and C—H⋯O hydrogen-bonding inter­actions.
doi:10.1107/S160053681000454X
PMCID: PMC2983736  PMID: 21580225
16.  Hexa­kis­(3-chloro-2-methyl­anilinium) cyclo­hexa­phosphate dihydrate 
In the organic/inorganic salt hydrate, 6C7H9ClN+·P6O18 6−·2H2O, the cyclo­hexa­phosphate anion resides on an inversion centre. The asymmetric unit consists of three cations, one half-anion and a water mol­ecule. In the crystal, the water mol­ecules and the [P6O18]6− anions are linked by O—H⋯O hydrogen bonds, generating infinite layers parallel to the ab plane. These layers are inter­connected by the organic cations through N—H⋯O hydrogen bonds.
doi:10.1107/S1600536813033230
PMCID: PMC3914095  PMID: 24527000
17.  Structure of magnesium selenate enneahydrate, MgSeO4·9H2O, from 5 to 250 K using neutron time-of-flight Laue diffraction 
Single-crystal neutron diffraction, ab initio calculations and Raman spectroscopy are applied to study the structure and hydrogen bonding of magnesium selenate enneahydrate, a recently discovered new hydration state in M 2+ XO4 hydrates and a unique example of a material with a cation: (oxy)anion:water ratio of 1:1:9, giving novel insights into the polymerization of water in highly hydrated materials.
The complete structure of MgSeO4·9H2O has been refined from neutron single-crystal diffraction data obtained at 5, 100, 175 and 250 K. It is monoclinic, space group P21/c, Z = 4, with unit-cell parameters a = 7.222 (2), b = 10.484 (3), c = 17.327 (4) Å, β = 109.57 (2)°, and V = 1236.1 (6) Å3 [ρcalc = 1770 (1) kg m−3] at 5 K. The structure consists of isolated [Mg(H2O)6]2+ octahedra, [SeO4]2− tetrahedra and three interstitial lattice water molecules, all on sites of symmetry 1. The positions of the H atoms agree well with those inferred on the basis of geometrical considerations in the prior X-ray powder diffraction structure determination: no evidence of orientational disorder of the water molecules is apparent in the temperature range studied. Six of the nine water molecules are hydrogen bonded to one another to form a unique centrosymmetric dodecamer, (H2O)12. Raman spectra have been acquired in the range 170–4000 cm−1 at 259 and 78 K; ab initio calculations, using density functional theory, have been carried out in order to aid in the analysis of the Raman spectrum as well as providing additional insights into the geometry and thermodynamics of the hydrogen bonds. Complementary information concerning the thermal expansion, crystal morphology and the solubility are also presented.
doi:10.1107/S2052520615006824
PMCID: PMC4450603  PMID: 26027007
magnesium selenate enneahydrate; dodecamer; neutron diffraction
18.  N,N,N,N′,N′,N′-Hexa­kis­(2-hy­droxy­ethyl)butane-1,4-diaminium bis­(2-sul­fan­ylidene-1,3-di­thiole-4,5-dithiolato-κ2 S 4,S 5)zincate 
In the asymmetric unit of the title compound, (C16H38N2O6)[Zn(C3S5)2], two independent cations lie across inversion centers. In one of the cations, the three symmetry-unique O—H groups are disordered over two sets of sites with refined occupancy ratios of 0.701 (9):0.299 (9), 0.671 (8):0.329 (8) and 0.566 (7):0.434 (7). In the anion, the ZnII ion is coordinated in a distorted tetra­hedral environment by four S atoms of two chelating 1,3-di­thiole-2-thione-4,5-dithiolato ligands. The dihedral angle between the mean planes [maximun deviations = 0.022 (3) and 0.0656 (6) Å] of the two ligands is 87.76 (3)°. An intamolecular O—H⋯O hydrogen bond occurs in the disordered cation. In the crystal, O—H⋯O and O—H⋯S hydrogen bonds link the components into a two-dimensional network parallel to (0-11).
doi:10.1107/S1600536813014992
PMCID: PMC3772409  PMID: 24046552
19.  Chlorido{μ-2,6-bis­[(2-amino­eth­yl)imino­meth­yl]-4-chloro­phenolato}-μ-oxido-dicopper(II) trihydrate 
In the title dinuclear complex, [Cu2(C14H20ClN4O)ClO]·3H2O, one CuII cation assumes a distorted square-planar coordination geometry and the other a distorted square-pyramidal coordination geometry. Both CuII cations are N,N′,O-chelated by one arm of the 2,6-bis­[(2-amino­eth­yl)imino­meth­yl]-4-chloro­phenolate anion, and one oxide anion bridges the two CuII cations, forming a dinuclear complex. One of the CuII cations is further coordinated by an Cl− anion in the apical direction. In the crystal, lattice water mol­ecules are linked with the complex mol­ecule via O—H⋯Cl hydrogen bonds while O—H⋯O hydrogen bonding occurs between lattice water mol­ecules , forming three-dimensional network structure.
doi:10.1107/S160053681202301X
PMCID: PMC3379123  PMID: 22719344
20.  Tris(1,10-phenanthroline-κ2 N,N′)nickel(II) bis­(2,4,5-tricarb­oxy­benzo­ate) monohydrate 
In the title compound, [Ni(C12H8N2)3](C10H5O8)2·H2O, the NiII cation is coordinated by six N atoms of the three bidentate chelating 1,10-phenanthroline ligands in a slightly distorted octa­hedral coordination geometry. The Ni—N bond lengths range from 2.074 (2) to 2.094 (2) Å. The dihedral angles between the three chelating NCCN groups to each other are 85.71 (3), 73.75 (2) and 85.71 (3)°, respectively. The Ni cation, the phenyl ring of the 1,10-phenanthroline ligand and the lattice water molecule are located on special positions (site symmetry 2). In the crystal, the uncoordinated 2,4,5-tricarb­oxy­benzeno­ate anions join with each other through O—H⋯O hydrogen bonds, forming a two-dimensional hydrogen-bonded layer structure along the bc plane. The layers are further linked via additional O—H⋯O inter­actions between water and carboxyl groups, resulting in a three-dimensional supra­molecular network.
doi:10.1107/S1600536811048914
PMCID: PMC3238718  PMID: 22199595
21.  Hexa­kis­(1H-imidazole-κN 3)iron(II) sulfate–1H-imidazole (1/2) 
The asymmetric unit of the title compound, [Fe(C3H4N2)6]SO4·2C3H4N2, contains two complex cations, two sulfate anions and four imidazole mol­ecules. In both cations, the FeII atom is coordinated by six monodentate imidazole ligands and exhibits a slightly distorted octa­hedral coordination geometry. The Fe—N distances [2.184 (4)–2.218 (4) Å] point to a high-spin state of the Fe2+ ions. N—H⋯O hydrogen bonds between the ionic components generate a three-dimensional framework containing corrugated channels along [001], which are filled by N—H⋯N hydrogen-bonded imidazole chains.
doi:10.1107/S1600536811043169
PMCID: PMC3247524  PMID: 22219829
22.  Bis[tetra­aqua­(1,10-phenanthroline-κ2 N,N′)cobalt(II)] hexa­aqua­cobalt(II) bis­[3,5-bis­(carboxyl­atometh­oxy)benzoate] tetra­hydrate 
The title compound, [Co(C12H8N2)(H2O)4]2[Co(H2O)6](C11H7O8)2·4H2O, was obtanied by the reaction of cobalt acetate with 3,5-bis­(carb­oxy­meth­oxy)benzoic acid and 1,10-phenanthroline. The asymmetric unit contains one tetra­aqua­(1,10-phenanthroline)cobalt(II) cation, one half of a hexa­aqua­cobalt(II) cation that is completed by inversion symmetry, one 3,5-bis­(carboxyl­atometh­oxy)benzoate trianion and two lattice water mol­ecules. The two CoII atoms each show a slightly distorted octa­hedral coordination (CoO6 and CoO4N2). The cations, anions and lattice water mol­ecules are linked by an intricate network of O—H⋯O hydrogen bonds into a three-dimensional structure.
doi:10.1107/S1600536810046386
PMCID: PMC3011475  PMID: 21589263
23.  Hexa­kis­(propyl­ammonium) benzene-1,2,4,5-tetra­carboxyl­ate 2,5-dicarb­oxy­benzene-1,4-carboxyl­ate tetra­hydrate 
The title organic salt, 6C3H10N+·C10H2O8 4−·C10H4O8 2−·4H2O, contains seven independent entities in the asymmetric unit which comprises three propyl­ammonium cations, two water mol­ecules, half a 2,5-dicarb­oxy­benzene-1,4-carboxyl­ate dianion (H2btc2−) and half a benzene-1,2,4,5-tetra­carboxyl­ate tetra­anion (btc4−), the latter two anions being located about centres of inversion. One of the water mol­ecules is disordered over two positions in a 0.55 (2):0.45 (2) ratio. The combination of mol­ecular ions and water mol­ecules results in an extensive and complex three-dimensional network of hydrogen bonds, the network being made up of nine unique N—H⋯O inter­actions between the ammonium cations and the anions, as well as four unique O—H⋯O inter­actions between the water mol­ecules and the anions.
doi:10.1107/S1600536812036501
PMCID: PMC3435833  PMID: 22969679
24.  Poly[[diaqua­bis­[μ4-5-nitro­isophthalato-κ4 O 1:O 1:O 3:O 3′]bis­[μ3-pyridine-4-carboxyl­ato-κ3 O:O′:N]tricobalt(II)] tetra­hydrate] 
The title compound, {[Co3(C6H4NO2)2(C8H3NO6)2(H2O)2]·4H2O}n, exhibits a two-dimensional layer-like structure in which the CoII ions exhibit two kinds of coordination geometries. One nearly octa­hedral CoII ion with crystallographic inversion symmetry is coordinated to six carboxyl­ate O atoms from four bridging 5-nitro­isophthalate (NIPH) ligands and two isonicotinate (IN) anions, while the other type of CoII ion binds with one N atom and one carboxyl­ate O atom from two IN anions, two carboxyl­ate O atoms from two different NIPH anions and one ligated water mol­ecule, displaying a distorted square-pyramidal coordination geometry. Three adjacent CoII ions are bridged by six carboxyl­ate groups from four NIPH ligands and two IN anions to form a linear trinuclear secondary building unit (SBU). Every trinuclear SBU is linked to its nearest neighbours in the ab plane, resulting in a two-dimensional layer-like structure perpendicular to the c axis. Along the a-axis direction neighbouring mol­ecules are connected through carboxyl­ate and pyridyl units of the IN anions, along the b axis through carboxyl­ate groups of the NIPH ligands. The H atoms of one free water mol­ecule are disordered in the crystal in a 1:1 ratio. Typical O—H⋯O hydrogen bonds are observed in the lattice, which include the following contacts: (a) between coordinated water mol­ecules and carboxyl­ate O atoms of the NIPH anions, (b) between lattice water mol­ecules and carboxyl­ate O atoms of the NIPH anions, and (c) between coordinated and lattice water mol­ecules. These inter­molecular hydrogen bonds connect the two-dimensional layers to form a three-dimensional supra­molecular structure.
doi:10.1107/S1600536812011269
PMCID: PMC3343849  PMID: 22589823
25.  Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O 
The crystal structures of ZnCl2·xH2O (x = 2.5, 3 and 4.5) consist of Zn2+ ions both in an octa­hedral and tetra­hedral environment. O—H⋯O hydrogen bonds between water mol­ecules and tetra­hedral ZnCl4 units lead to the formation of a three-dimensional network in each of the structures.
The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetra­hedral coordination with Cl− and in an octa­hedral environment defined by five water mol­ecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O)5] (penta­aqua-μ-chlorido-tri­chlorido­di­zinc). The trihydrate {hexa­aqua­zinc tetra­chlorido­zinc, [Zn(H2O)6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetra­hedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octa­hedrally surrounded by water mol­ecules. The [ZnCl4] tetra­hedra and [Zn(H2O)6] octa­hedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexa­aqua­zinc tetra­chlorido­zinc trihydrate, [Zn(H2O)6][ZnCl4]·3H2O}, consists of isolated octa­hedral [Zn(H2O)6] and tetra­hedral [ZnCl4] units, as well as additional lattice water mol­ecules. O—H⋯O hydrogen bonds between the water mol­ecules as donor and ZnCl4 tetra­hedra and water mol­ecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.
doi:10.1107/S1600536814024738
PMCID: PMC4257420  PMID: 25552980
crystal structure; low-temperature salt hydrates; chloride hydrates; zinc salts

Results 1-25 (763829)