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The crystallographic analysis of complex, NH4[Cr(CO(NH2)2)6][Hg(SCN)4]2⋅2H2O (1) has revealed that its cations and anions are held together by secondary non-covalent interactions. These interactions have led to the formation of four σ-holes, one on Hg and three on S atoms. The molecular electrostatic potential (MEP) study confirms that the σ- holes on sulphur are large enough to generate interactions between S...S (chalcogens) and S...N (chalcogen-pincogen) in [Hg(SCN)4]2−. Single crystal X-ray diffraction of 1 has revealed that [Cr(CO(NH2)2)6]3+ are stacked one upon another running parallel along a-axis and surrounded by a “cylinder” consisting of anions, ammonium cations and water molecules. The supramolecular architecture has been obtained which is being stabilized by intermolecular hydrogen bonding interactions (O-H⋅⋅⋅N, O-H⋅⋅⋅S, N-H⋅⋅⋅N, N-H⋅⋅⋅O (H2O)) along with the formations of σ-hole interactions. The crystals of 1 has been obtained using one-pot synthetic method by reacting [Cr(CO(NH2)2)6]Cl3⋅3H2O, HgCl2 and NH4SCN (in 1:2:8 molar ratio) in aqueous medium and have been initially characterized by UV-visible and IR spectroscopy.

Two different quaternary ammonium cations, methyltriethyl- (MTEA) and tetraethylammonium cations (TEA) were used as templates in the synthesis of pure-silica as well as aluminosilicate ZSM-12 (MTW-type) frameworks. The distribution of the template cations in the 12-membered rings channels in the 1-dimensional framework topology was studied; thus the as-prepared products were characterized by means of X-ray powder diffraction, Raman, transmission FTIR, solid-state NMR spectroscopy, thermogravimetric and elemental analyses and SEM. It was shown that in pure-silica (PS) ZSM-12, TEA cations are well ordered - a superstructure with three-times longer b edge (in comparison to unit cell of empty framework) along the channel is formed, which can be seen by virtue of a few additional peaks in the X-ray powder pattern. Herein we describe that its aluminosilicate counterpart with TEA also contains ordered TEA cations and is isostructural to PS-ZSM-12. Conversely, in both pure-silica and aluminosilicate ZSM-12 frameworks with MTEA, the cations are disordered and no superstructure is formed.

Microporous triclinic AlPO4-34, known as APO-Tric, serves as an excellent water adsorbent in thermal energy storage, especially for low temperature thermochemical energy storage. Increased water adsorption capacity of thermochemical material usually leads to higher thermal energy storage capacity, thus offering improved performance of the adsorbent. The main disadvantage of aluminophosphate-based TCM materials is their high cost due to the use of expensive organic templates acting as structure directing agents. Using ionic liquids as low cost solvents with associated structure directing role can increase the availability of these water adsorbents for TES applications. Here, a green synthesis of APO-Tric crystals at elevated and ambient pressure by using 1-ethyl-3-methyl imidazolium bromide ionic liquid is presented. Large 200 µm romboid shaped monocrystals were obtained at 200 °C after 6 days. The structure of APO-Tric and the presence of 1,3-dimetylimidazolium cation in the micropores were determined by single crystal XRD at room temperature and 150 K. Water sorption capacity of APO-Tric prepared by ionothermal synthesis at elevated pressure increased in comparison to the material obtained at hydrothermal synthesis most probably due to additional structural defects obtained after calcination. The reuse of exhausted ionic liquid was also confirmed, which adds to the reduction of toxicity and cost production of the aluminophosphate synthesis.

A proton transfer compound, (ABTH)+(PydcH)− (1), obtained from 2-aminobenzothiazole (ABT) and 2,6-pyridinedicarboxylic acid (Pydc) as well as its Eu(III), Tb(III), and Cu(II) complexes (ABT)3[Eu(Pydc)3]·5H2O (2), (ABT)3[Tb(Pydc)3]·5H2O (3), and (ABT)[Cu(Pydc)(PydcH)]·3H2O (4) were obtained under ambient conditions and structurally verified by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and magnetic measurements. Compounds 2–4 are the first known solids containing complex anions with Pydc ligands, 2-aminobenzothiazole cations (ABT), and solvate water molecules. During the synthesis of 3, a secondary phase with the formula ABTCl∙H2O was obtained and characterized by elemental analysis and single-crystal X-ray diffraction. The asymmetric unit of 5 consists of six symmetry independent ABT cations, six chlorides, and six water molecules. The two lanthanide complexes showed characteristic emissions of Eu3+ and Tb3+ ions. The good solubilities of these complexes in water and their luminescence properties make them attractive luminescent labels of biological molecules.

Symmetric [4-np…H…4-np]− and unsymmetric [4-np-H…4-np−] dimers of 4-np− have been isolated in s-fac-[Co(dien)2](4-np)3(4-npH)·2H2O (dien = diethylenetriamine) using a one pot synthesis. The crystal structure of the title complex revealed a strong network of H-bonding interactions which lead to the formation of layers of [H(4-np)2]− (symmetric and unsymmetric), s-fac-[Co(dien)2]3+ and water molecules. These layers formed their respective columns and the intermolecular cohesion of 4-npH within the columns of the 4-np− ions is achieved via nitro–π and π-π stacking interactions. Water also played a dominant role in stabilizing the structure, in which the H O H…O (4-np−) interaction is weaker than [4-np…H…4-np]− , but stronger than the N H…O (4-np)− and N H (dien)…O H O interactions. The H-bond present in the symmetric dimer is the strongest one, having an O…O contact distance of 2.433(3) A. The presence of the s-fac-isomer of the cation is also supported by IR and 1H, 13C and 2D 1H–13C NMR spectroscopy. The XRD pattern of the product (bulk) was also determined and it shows the presence of a single phase. The binding capacity (log β = 27.101 ± 0.06) of [Co(dien)2]3+ with the 4-np− was determined by UV–vis spectroscopic titrations and the ionic behaviour of the complex was confirmed by molar conductance measurements at infinite dilution (λo = 800 S cm2 mol−1).

The coordination compounds of pyridine-2,6-dicarboxylic acid and two lanthanide(III) ions, Ho3+ and Dy3+, were hydrolytically synthesized in aqueous solutions at a slightly basic pH, and then characterized by thermogravimetric analysis, IR spectroscopy, magnetic measurements as well as X-ray powder and single-crystal diffraction analysis. The elemental analyses were performed to check the purity of the compounds. The formula for these compounds is identified as Na3[Ln(Pydc)3]⋅14H2O (Ln = Ho, 1; Ln = Dy, 2) in agreement with the X-ray structural analysis and all the other experimental data. The absence of the 1709 cm−1 band corresponding to ν(С O) in the IR spectra of the compounds evidences the deprotonating of the carboxyl group. The very strong inductive effect of the metal ion that is readily coordinated by the carboxylate group of the zwitterionic ligand is responsible for the formation of the product. The single-crystal X-ray structural analysis revealed that compounds 1 and 2 are isostructural. Their structure can be described as interchanging layers of complex anions [Ln(Pydc)3]3 (Ln = Ho and Dy for 1 and 2, respectively) and layers of hydrated sodium cations. In complex anions the holmium and dysprosium atoms are coordinated by three crystallographically independent pyridinedicarboxylate ligands in tridentate-chelate mode, via one O atom of both carboxylate groups and the ring N atom. The coordination number is nine and the coordination polyhedron is a tricapped trigonal prism with O atoms at the corners.

This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula $(NH_3OH)_3FeF_6$, obtained after dissolving iron powder in hydrofluoric acid and adding solid $NH_3OHF$. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. The structure consists of $NH_3OH^+$ cations and isolated $FeF_6^{3–}$ octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment $µ_{eff}$ = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction. V prispevku poročamo o sintezi novega hidroksilamonijevega fluorometalata s formulo $(NH_3OH)_3FeF_6$. Spojino smo pripravili z reakcijo med trdnim $NH_3OHF$ in vodno raztopino železa v $HF$. Spojino smo karakterizirali s kemijsko in termično analizo, rentgensko difrakcijo na monokristalu in magnetnimi meritvami. Hidroksilamonijev fluoroferat kristalizira trigonalno, R3c, s parametri osnovne celice a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. Strukturo sestavljajo kationi $NH_3OH^+$ in izolirani oktaedri $FeF_6^{3–}$, v katerih centralni atom leži na trištevni osi. Kisikovi in dušikovi atomi v hidroksilamonijevih kationih so donorji vodikovih vezi do fluoridnih anionov, kar povzroči nastanek mreže vodikovih vezi. Izračunani efektivni magnetni moment $µ_{eff}$ = 5.8 BM se odlično ujema s teoretično vrednostjo za visokospinske Fe(III) ione. Termični razkroj spojine smo preučevali s termogravimetrično metodo in rentgensko praškovno analizo.

New hydroxylammonium fluorometallates of manganese and scandium, with the formulas (NH 3 OH) 2 MnF 4 and (NH 3 OH) 3 ScF 6 , were prepared by the reactions of hydroxylammonium fluoride with solutions of manganese or scandium in aqueous HF. (NH 3 OH) 2 MnF 4 crystallizes monoclinic, P 2 1 / c , the structure consisting of MnF 6 octahedra sharing four of its vertices, resulting in [ Mn F 4 2 − ] n anionic layers perpendicular to a axis. (NH 3 OH) 3 ScF 6 crystallizes trigonal, R 3 c , and the structure is made up of isolated ScF 6 octahedra, stacked in columns along c axis and surrounded by a cylinder of hydroxylammonium cations. Both title compounds decompose during thermal analysis in several steps, yielding corresponding fluorides (MnF 2 and ScF 3 ) at temperatures between 300 and 400 °C and oxides/oxofluorides at higher temperatures.

The reaction of an isomeric mixture of [Co(dien)2]Cl3 with sodium salt of p-aminobenzoic acid in aqueous medium leads to the formation of dark orange coloured crystals of composition s-fac-[Co(dien)2]Cl(p-aminobenzoate)2·3H2O. The configuration of the cationic isomer was initially determined with the help of spectroscopic data (NMR, UV–Vis, and IR). The binding properties of s-fac-bis(diethylenetriamine)cobalt(III) cation with p-aminobenzoate anion has been determined (in solution phase) with the help of UV–Vis spectroscopic titrations. Single crystal X-ray structure determination of title complex reveals the presence of one cation, three anions (one Cl and two p-aminobenzoates) along with three lattice water molecules. The crystal lattice is stabilized by electrostatic forces of attraction and H-bond interactions (N–H···O, N–H···Cl, O–H···O, and O–H···Cl). The water molecules of crystallization play a major role in stabilizing the complex by forming intermolecular H-bonds with Cl− and O atoms of p-aminobenzoate and water.

This article reports the synthesis of novel, rare-earth coordination complexes with nicotinic acid. Three compounds with the general formula Ln2[(C5H4NCOO)6(H2O)4] (Ln = Yb, 1; Ln = Gd, 2; Ln = Nd, 3) were prepared from relatively cheap and readily available reactants. Their compositions and structure were characterized by IR spectroscopy and single-crystal X-ray diffraction. The magnetic and thermogravimetric properties were also studied. The complexes consist of centrosymetric, dimeric molecules having all six nicotinato ligands coordinated with the central atom in the bidentate mode. The coordination environment of the Ln3+ for all three compounds is 8. Here we describe the crystal structure of Yb and Gd complexes with nicotinic acid.

The new anion [Cr2(CO(NH2)2)2(C6H4O7)2]2 − has been isolated in the complex [Cr(CO(NH2)2)6]2[Cr2(CO(NH2)2)2(C6H4O7)2]3. The crystals of this complex were obtained by a one-pot synthetic method using 1:1 molar ratio of hexaureachromium(III) chloride and trisodium citrate in aqueous medium. It was characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction analysis. The compound crystallizes in space group R‾3 of the trigonal system with three formula units in a cell of dimensions a = b = 24.7461(4) A, c = 13.7204(3) A and γ = 120°. The crystal structure comprises the columns consisting of [Cr(CO(NH2)2)6]3 + cations surrounded by a cylinder of complex anions, [Cr2(CO(NH2)2)2(C6H4O7)2]2 − which are packed in a honeycomb-like manner. This supramolecular architecture is formed and stabilized by inter- and intramolecular N H⋯O hydrogen bonds.

The hourglass shaped molecular receptor, [Cr(CO(NH2)2)6]3+ has been recognized and its binding properties with oxoanions ( Cr 2 O 7 2 - and CrO 4 2 - ) were studied. Binding constants with different potassium salts of oxoanions were determined by standard UV–vis titration techniques in aqueous medium. According to the titration data, receptor containing six urea molecules exhibits high affinity (log K = 3.7–3.8) for oxoanions in the presence of Cl−. The UV–vis spectroscopic titration data were found to fit well to a 2:3 binding model for the interactions between the receptor and Cr 2 O 7 2 - and 1:2 for receptor and CrO 4 2 - . The newly synthesized receptor-anion complexes were also characterized by elemental analyses and IR spectroscopy. Single crystal X-ray study of [Cr(CO(NH2)2)6]2(Cr2O7)3 reveals the structure with a honeycomb-like pattern, consisting of columns of coordination cations, running parallel to c axis, being surrounded by a “cylinder” of oxoanions. The structure is stabilized by strong charge assisted (HNH⋯OCr) intermolecular hydrogen bonds (CAHB) between cations and anions and intramolecular (CO⋯HNH) hydrogen bonds within cations.

The positron-emission tomography (PET) probe 2-(1-[6-[(2-fluoroethyl)(methyl)amino]-2-naphthyl]ethylidene) (FDDNP) is used for the noninvasive brain imaging of amyloid-β (Aβ) and other amyloid aggregates present in Alzheimer’s disease and other neurodegenerative diseases. A series of FDDNP analogs has been synthesized and characterized using spectroscopic and computational methods. The binding affinities of these molecules have been measured experimentally and explained through the use of a computational model. The analogs were created by systematically modifying the donor and the acceptor sides of FDDNP to learn the structural requirements for optimal binding to Aβ aggregates. FDDNP and its analogs are neutral, environmentally sensitive, fluorescent molecules with high dipole moments, as evidenced by their spectroscopic properties and dipole moment calculations. The preferred solution-state conformation of these compounds is directly related to the binding affinities. The extreme cases were a nonplanar analog t -butyl-FDDNP, which shows low binding affinity for Aβ aggregates (520 nM K i ) in vitro and a nearly planar tricyclic analog cDDNP, which displayed the highest binding affinity (10 pM K i ). Using a previously published X-ray crystallographic model of 1,1-dicyano-2-[6-(dimethylamino)naphthalen-2-yl]propene (DDNP) bound to an amyloidogenic Aβ peptide model, we show that the binding affinity is inversely related to the distortion energy necessary to avoid steric clashes along the internal surface of the binding channel.

A new coordination compound of zinc fluoride and hydroxylammonium, (NH3OH)2ZnF4, was obtained after dissolving zinc powder in hydrofluoric acid (40%) and adding solid hydroxylammonium fluoride. The colourless crystals were characterised chemically, magnetically, structurally by single-crystal X-ray diffraction analysis, and thermogravimetrically by TGA and DSC analysis. The structure consists of NH3OH+ cations and ZnF6 octahedra in which the metal ion lies on the inversion centre. Each of the ZnF6 octahedra shares four of its vertices in a way that each vertex is shared between two octahedra. Oxygen and nitrogen atoms of hydroxylammonium cations are donors of hydrogen bonds. Hydroxylamonium fluorozincate crystallizes monoclinic, P21/c, with cell parameters a = 8.1604(4) A, b = 5.8406(3) A, c = 5.6586(2) A and β = 94.745(3)°. The compound decomposes above 373 K in four steps, obtaining ZnO as the final residue. Magnetic properties of the compound were studied between 2 and 300 K, giving the prevailing diamagnetic behaviour with room temperature susceptibility of −9 × 10−5 emu mol−1.

The synthesis and characterization of two new nickel(II) coordination compounds with 3- and 4-aminopyridine are reported. They were obtained after dissolving Ni(CH3COO)2·4H2O in different solutions of 3- and 4-aminopyridine. The products were characterized magnetically, structurally by single-crystal X-ray diffraction analysis, and spectrally by FT-IR spectroscopy. Dark green crystals of the polymeric coordination complex {[Ni(O2CCH3)2(3-apy)2]·H2O} n were synthesized by the reaction of Ni(CH3COO)2·4H2O and 3-aminopyridine (3-apy). The molecular structure of this complex consists of a zigzag chain in which nickel(II) ions are connected by bridging 3-aminopyridine ligands. The Ni(II) ion is six-coordinated by three oxygen atoms from two acetate ligands, one chelating and one monodenate, and by three nitrogen atoms from three 3-aminopyridine ligands, one terminal and two bridging ones. The blue crystals obtained by the reaction of Ni(CH3COO)2·4H2O with 4-aminopyridine (4-apy) consist of the monomeric complex [Ni(O2CCH3)2(4-apy)2(H2O)2], in which the ligands possess trans geometry around the Ni(II) ion. The interactions including intra- and intermolecular hydrogen bonds in the crystal structures of both complexes are discussed. Magnetic properties of both compounds were studied between 2 and 300 K giving the result of μ eff = 3.1 BM in the paramagnetic region.

Hydroxylammonium fluoroaluminate with the formula (NH3OH)2AlF5 was synthesized by the reaction of solid NH3OHF and an aqueous solution of aluminum in HF, and its structure was determined by single-crystal X-ray diffraction. The structure consists of NH3OH+ cations and centrosymmetrical AlF6 octahedra, which are formed by sharing two opposite corners connected in polymeric (AlF5) n 2− anions. Oxygen and nitrogen atoms of hydroxylammonium cations are donors of hydrogen bonds to terminal fluorine atoms of fluoroaluminate chains. The compound crystallizes monoclinic P2/c, with cell parameters a = 10.8675(3) A, b = 7.3098(2) A, c = 7.2071(2) A, and β = 91.080(2)°. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction. By controlled heating of (NH3OH)2AlF5, a new compound with the formula (NH3OH)AlF4 was obtained, and the final product of the decomposition is γ-AlF3.

A single-crystal X-ray diffraction analysis of an open-framework aluminophosphate ULM-3 Al prepared by 3-methylaminopropylamine (MAPA) as structure-directing agent revealed an orthorhombic Pcab symmetry (a=9.9949(4) A, b=15.8229(7) A, c=18.1963(5) A, R=0.0648, Z=8, unit cell formula [Al{sub 24}P{sub 24}O{sub 96}F{sub 16}.C{sub 32}H{sub 112}N{sub 16}]), which differs from the Pbc2{sub 1} symmetry of the structural analogue prepared in the presence of 1,4-diaminobutane. The {sup 27}Al, {sup 31}P, {sup 19}F, {sup 13}C and {sup 1}H NMR investigations, which were performed to study in detail MAPA arrangement inside the framework as well as the interactions of MAPA with the aluminophosphate host, confirmed the crystal symmetry and the proposed hydrogen bonding scheme between the template and the framework. - Graphical abstract: The aluminophosphate analogue of open-framework gallophosphate ULM-3 was synthesized in the presence of 3-methylaminopropylamine. The Pcab crystal symmetry and hydrogen bonding scheme was determined by single-crystal X-ray diffraction and NMR spectroscopy.

Successful Rietveld refinements of seven compounds with the formulae La2Ti(1−x)Ga x O(5−x/2), where x = 0.00, 0.20, 0.50, 0.70, 0.90, 0.95 and 1.00, were performed in order to describe the solid solubility between orthorhombic (Pnam) La2TiO5 and monoclinic (P21/c) La4Ga2O9. The relationship between the end-member structures, which are already known, is discussed; the space-group change is a consequence of ordering the oxygen vacancies that become more numerous as Ga is substituted for Ti. The structures of the solid solutions are also described. The lengths of cell edges obey Vegard's rule.

Pure-silica ZSM-12, containing tetraethylammonium cations (TEA) was synthesized using a ‘two-silica’ source strategy and its structure was determined from laboratory X-ray powder diffraction data. This is the first known zeolite structure in which the positions of the TEA cations have been established. The ordered arrangement of TEA cations in the straight nonintersecting channels of the host material, which is reflected in several weak superstructural diffraction peaks, was determined by using the combination of simulated annealing and Rietveld refinement. In accordance with Raman spectroscopy, the calculations confirmed the presence of a tt . tt form of the TEA cations and the absence of the other stable form ( tg . tg ) which was also consistent with the dimensions and elliptical cross-section of the channels. Therefore in ZSM-12 structure pore (channels) geometry is directly connected with the conformation of TEA cations. The compound with a moiety formula C 16 H 40 N 2 O 84 Si 42 ( M r = 2784.28, Z = 4) crystallizes in the monoclinic Cc space group with unit cell parameters a = 25.2177(9), b = 15.1903(5), c = 24.4754(7) A, β = 108.516(2)°. The final structure, which resulted in a good agreement between calculated and observed powder diffraction pattern ( R wp = 10.17%), was additionally confirmed by results from thermogravimetric measurements and FTIR spectroscopy.

A novel dinuclear complex [Cu2(μ-L)4(HL)2] (1) was isolated from starting 2-pyridone (HL) via a resonance and a tautomeric transformation. Each copper centre is in a square-pyramidal coordination sphere, defined by two oxygen atoms (Cu–O4 1.978(5), Cu–O11 1.964(4) A) and two nitrogen atoms (Cu–N2 2.003(5), Cu–N3 2.007(5) A) of four bridging deprotonated pyridin-2-olates and an oxygen atom on the top from a neutral 2-pyridone (Cu–O2 2.227(5) A), analogous to tetracarboxylate paddle-wheel complexes. Compound 1 was compared with mixed pyridin-2-olato/methanoato analogues [Cu2(μ-HCO2)2(μ-L)2(HL)2] · 2CH3CN (2) and [Cu2(μ-HCO2)2(μ-L)2(HL)2] (2a) (2a is an air stable form obtained from 2 outside mother-liquid). The EPR spectra of air stable 1 and 2a show three signals Hz1, H⊥2 and Hz2, typical for the binuclear systems with spin S = 1, both revealing strong antiferromagnetism 2J = −334 (1) and −324 cm−1 (2a). Interestingly, only for 1 additional H⊥1 signal at 100 mT is noticed (D(1) = 0.293 cm−1

The Li1.746Nd4.494FeO9.493 (LNF) ternary phase, located in the Li2O-rich part of the Li2O–Nd2O3–Fe2O3 system, crystallizes with a cubic unit cell of dimension a = 11.9763 ( 3 ) A and the space group Im 3 m . Refinement on F resulted in R = 1.9 % . The structure is comprised of a network of corners, edges and faces sharing the coordination polyhedra of neodymium. In between this skeleton the regular octahedra of oxygen-coordinated iron and trigonal prisms of lithium are located. The Mossbauer spectra revealed the presence of Fe3+, Fe4+ and Fe5+ ions distributed on two symmetry-independent lattice positions.

Two novel polynuclear complexes with methanoate anions and 3-hydroxypyridine ligands [Cu(l-HCO 2 ) 2 (3-pyOH)] n (1) and [Cu 2 -(l-HCO 2 ) 2 (l-3-pyOH) 2 (3-pyOH) 2 (HCO 2 ) 2 ] n (2), respectively, were synthesized and characterized. The central copper atom in 1 is sur-rounded by four methanoates and a 3-pyOH molecule, forming a square-pyramidal CuO 3 NO chromophore. All the methanoates arebidentate and serve as bridges between the adjacent copper ions via syn-anti and anti–anti coordination. The basal square coordinationaxes are formed by O(syn), N(3-pyOH) (1.974(2), 2.016(2) A˚) and O(anti), O(anti) (1.945(2), 1.960(2) A˚), while the third O(anti)(2.247(2) A˚) is on the top of the pyramid. A ferromagnetic transition with an exchange constant 2J/k B = 9.2 cm 1 is found for 1 below20 K. This interaction probably takes place through two syn-anti methanoates extended in a chain through the 2D structure. On theother hand, two monoatomic Cu–O–Cu intra-dinuclear asymmetric (1.986(2), 2.415(2) A˚) bridges of two methanoates in[Cu

The crystal structure of cis-[Cu(C8H7O3)2(H2O)2] (115 K data) reveals bidentate vanillinate ions coordinated via methoxy and deprotonated hydroxy oxygen atoms and water molecules in a distorted octahedral CuO6 chromophore. A cis orientation of the ligands enables two non-identical O(methoxy) Cu O(water) coordination axes (2.354(1) + 2.163(1); 2.151(1) + 2.020(1) A), and the third shortest O(hydroxy) Cu O(hydroxy) axis (1.919(1) + 1.914(1) A). This 115 K coordination sphere differs importantly to the one obtained from the 293 K data of the same compound, where two long O(methoxy) Cu O(water) axes are of the same length, and only minor changes at the short O(hydroxy) Cu O(hydroxy) axis are noticed. An axial symmetry of the complex with an inverse g 1 , 2 ( g ⊥ ) > g 3 ( g ∥ ) pattern is observed in the temperature range from 298 to 180 K. A further decrease of temperature reveals gradual changes from axial to rhombic symmetry (g1 > g2 > g3) that is reversible. A mean-square displacement amplitude (MDSA) analysis reveals a disorder in the Cu O(methoxy) bonds, but not in the other metal ligand Cu O(hydroxy) and Cu O(water) bonds at 293 and 115 K. The disorder is significantly weaker in the 115 K structure. The MSDA analysis and the structural-EPR agreement show vibrational disorder in two coordination axes, due to the cis conformation of the complex with two O(methoxy) Cu O(water) axes.

Two copper(II) coordination compounds with vanillic acid C8H8O4 (1), namely [Cu- 2(C8H7O4)(2)(O2CCH3)(2)(CH3OH)(2)] (2) and [Cu-2(C8H7O4)(4)(H2O2)(2)] (3), were synthesized and characterized. Single crystals of 1-3 were obtained and their crystal structures determined. The structure of 2 shows dinuclear cage structure of copper acetate hydrate type, however with two different carboxylates, acetates and vanillic acid anions,. respectively. Both bridging anions are in pairs in trans orientation. Methanol molecules are apically coordinated (Cu-O7 2.160(2) angstrom), fulfilling square-pyramidal coordination sphere around both copper ions. The compound 2 decomposes outside mother-liquid (yielding [Cu-2(C8H7O4)(2)(O2CCH3)(2)(H2O)(2)] (2a)) with the removal of methanol, but without significant change of the dicopper tetracarboxylate cage structure, as noticed by mu(eff) 1.48 BM for 2a. Similar was found also in the X-band EPR spectra with three signals H-z1, H-perpendicular to 2 and H-z2 in the region from 0 to 600 mT. The structure of free vanillic acid 1 is composed of dimeric units of two molecules, connected by two parallel hydrogen bonds between carboxylate group of each other (O1-H(...)O2 2.642(3) angstrom), while the structure of 3 is of [Cu-2(O2CCH3)(4)(H2O)(2)] type. Interestingly, an additional signal in the EPR spectra of 3 is found at 80 mT (H- perpendicular to 1) at 298 and at 116 K, next to three signals H-z1, H-perpendicular to 2 and H-z2.

By refluxing of a mixture of (NH4)2[MoCl5(H2O)] and KOCN in pyridine, the neutral mer-[Mo(NCO)3py3] and anionic trans-[Mo(NCO)4py2]− species originated simultaneously at reflux temperature. After a separation of the water-unsoluble neutral and water-soluble ionic species, the single crystals of compounds [Mo(NCO)3py3] · 2py (1) and (py2H)[Mo(NCO)4py2] (2) have been prepared and crystal structures of both were determined by X-ray crystallography.

A new pyrazole-based ligand, namely 1,3-bis(3,5-dimethylpyrazol-1-yl)-2-butanoic acid (Hbdmpb) was synthesised together with its copper complex Na[Cu(bdmpb) 2 (OOCCH 3 )H 2 O] · 4H 2 O. Both the free ligand and its Cu compound were fully characterised and their crystal structures were determined by X-ray analysis. The free-ligand molecular structure is uneventful. The Cu compound is highly unusual, as the pyrazole nitrogen atoms do not bind to the Cu ion. The copper(II) ion is coordinated by four nearly coplanar oxygen atoms from two dehydronated ligands bdmpb (Cu O(1a) 1.942(4), Cu O(1b) 1.933(4) A), a monodentate acetate group (CuO(1) 1.927(3) A) and a water molecule (Cu O(1w) 1.937(4) A). The nitrogen atoms of the pyrazole rings do not coordinate to the metal center, but instead are involved in strong intramolecular hydrogen bonds. The coordinated water molecule is strongly H-bonded to two pyrazole N atoms from two bdmpb ligands (N(12a) ⋯ H O(1w) 2.762(7), N(12b) ⋯ H O(1w) 2.774(7) A). The other two pyrazole N atoms with a lone pair are hydrogen-bonded to water molecules in the lattice (N(22a) ⋯ H O(2w) 2.763(7), N(22b) ⋯ H O(6w) 2.892(7) A). The sodium ion is six-coordinated by the oxygen atom O(2) of the acetato ligand and by five water molecules. The EPR spectrum recorded in the solid state shows a characteristic signal for an axial anisotropic S = 1/2 species. The spectrum recorded in methanol glass confirms the absence of the coordination of pyrazole nitrogen atoms to the copper centers.

Colorless plate-like crystals (AIPO-1,2DAP) crystallize from a clear 'AlPO4-1,2-diaminopropane' reaction system. The results of elemental, thermal and FTIR analyses give the following chemical formula: (NH4+)(1,2-H(2)DAP)(2+)(AlP2O8)(3-), confirmed also by single crystal structure determination. The X-ray diffraction data collected at 150 K reveal the space group Pc2(1)n with a = 8.2788(2), b = 16.7882(3), c = 8.6608(2) Angstrom, and V = 1203.73(5) Angstrom(3). The AIPO-1,2DAP has a chain structure related to the aluminophosphate AlPO-enA structure. Two occluded cations, NH4+ and doubly protonated diamine, balance the negative charge and interact with the chain oxygen atoms via hydrogen bond network.

The interactions of quinolone ciprofloxacin (cfH) and oxovanadium(IV) were studied by various methods. Green crystals of a complex [V(IV)O(cf)(2)(H(2)O)] were isolated and the molecular connectivities established, although the crystal structure was not perfectly refined due to the instability of the crystals. Based on a plausible interpretation of the data sets, two cf anions bidentately coordinate to a vanadyl cation through carboxylate and carbonyl oxygen atoms; in addition, there is a water molecule in the coordination sphere. Solution techniques (cyclic voltammetry, electronic and electron paramagnetic resonance spectroscopy, potentiometric measurements) confirmed the presence of various species in the solution, the composition of which strongly depends on the conditions in the system. The antibacterial activity of the complex against various microorganisms was tested and it was established that its activity is similar to that of free ciprofloxacin.

Two ammonium zinc gallophosphates (I) (NH 4 ) 16 [Zn 16 Ga 8 P 24 O 96 ] and (II) (NH 4 ) 4 [Zn 4 Ga 4 P 8 O 32 ] were hydrothermally synthesized and characterized using single crystal X-ray diffraction. The (I) (NH 4 ) 16 [Zn 16 Ga 8 P 24 O 96 ] crystallizes in a cubic I 2 1 3 space group ( a =13.456(1) A, V =2436.5(5) A 3 , R (on F )=2.47%, R w (on F )=2.48%). It has a zeolite analcime topology with distorted eight-member ring channels. Zn and Ga atoms share the same crystallographic site with a partial occupancy of Zn/Ga=0.67/0.33. Ammonium ions lie on the three-fold crystallographic axes and compensate for a negatively charged framework. The second compound (II) (NH 4 ) 4 [Zn 4 Ga 4 P 8 O 32 ] has a monoclinic symmetry ( P 2 1 /a, a =9.406(1) A, b =9.881(1) A, c =8.612(1) A, β =90.58(1)°, R (on F )=2.7%, R w (on F )=3.0%). It is isostructural with a feldspar paracelsian. Zinc and gallium occupy two crystallographic sites with a partial occupancy of Zn(1)/Ga(1) =0.53(6)/0.47(6) and Zn(2)/Ga(2)=0.47(6)/0.53(6). Ammonium ions lie in the elliptical eight-member ring openings of the three-dimensional framework.

Three X-ray structure analyses and theoretical conformational analyses combining molecular mechanics (SYBYL), semiempirical (AM1) and ab initio (HF/6-31G ∗ ) calculations of nine 2,3-substituted propenoates are presented. The results of the quantochemical and crystallographic calculations and a survey of structural related molecules using the Cambridge Structural Database System are in concordance and show that steric hindering among substituents and possible inter and intramolecular hydrogen bonding are major factors that influence the geometrical configuration of substituents. The physical and chemical sense of these factors and the reasonable agreement between the semiempirical and ab initio results as well as between theoretical and experimental results have confirmed that the method which was applied for the theoretical conformational analysis is good and useful for related organic molecules.

Two new cobalt complexes: Co3(NO2)4(NH2CH2CH2O)4·H2O (1) and (NH2(C6H11)2)3[Co2(NO2)8OH]·3H2O (2) and the compound (NH2(C6H11)2)NO2 (3) were synthesised and their structures have been determined using single-crystal X-ray diffraction. Compound 1 consists of two centrosymmetrical trinuclear complexes and a water molecule of crystallization. Ligands coordinated to Co atoms are nitro and aminoethanolato groups. Structure 2 is built up of biscyclohexylammonium cations, dinuclear anions with hydroxo and nitro groups coordinated to Co atoms and water molecules. The coordination of Co atoms in both structures is roughly octahedral.

The novel title polymeric copper(II) complex, {Na2[Cu3-(CHO2)8]}n, consists of sodium cations and infinite anionic chains, in which neutral dinuclear [Cu2(O2CH)4] moieties alternate with dianionic [Cu(O2CH)4]2- units. Both metal-containing moieties are located on crystallographic inversion centers. The syn-syn bridging configuration between the mononuclear and dinuclear components yields a structure that is significantly more dense than the structures previously reported for mononuclear-dinuclear copper(II) carboxylates with syn-anti or anti-anti bridging modes.

In the title compound, [Cu2(CHO 2 ) 2 (C 6 H 4 NO)2(C 5 H 5 NO) 2 ]-1.02CH 3 CN, the dimeric unit is centrosymmetric, with two bidentate pyridin-2-olate and two bidentate formate syn-syn bridges, and two apical 2-pyridone ligands coordinated through the O atoms. The N atom from the apical 2-pyridone ligand is a donor of a hydrogen bond to the O atom of the bridging pyridinolate ligand of the same complex. The coordination polyhedron of the Cu atom is a distorted square pyramid.

The title compound, catena-poly[[N-methylpropane-1,3diaminium [mu-phosphato-(mu-hydrogen phosphato)(mu-dihydrogen phosphato) dizincate(II)]], {(C4H14N2)[Zn-2(PO4)(HPO4)(H2PO4)]}(n), consists of macroanionic [Zn-2(PO4)(HPO4)(H2PO4)](2-) layers and intercalated (C4H12N2)(2+) cations. The layers are built up from ZnO4 and PO4/HPO4/H2PO4 tetrahedra that result in small channels of approximate diameter 3.7 angstrom within the layers. Framework-to-framework O - H center dot center dot center dot O and template-to-framework N - H center dot center dot center dot O hydrogen bonds are important in stabilizing the structure.

In the title compound, [Fe(C(5)H(5))(C(14)H(13)O)], the plane of the heterocyclic ring is almost perpendicular to the plane of the substituted cyclopentadienyl ring, and the heterocyclic ring adopts a half-chair conformation. The conformation of the nearly parallel cyclopentadienyl (Cp) rings [the dihedral angle between their planes is 2.7 (1) degrees ] is almost halfway between eclipsed and staggered, and the rings are mutually twisted by about 19.4 (2) degrees (mean value). The mean lengths of the C-C bonds in the substituted and unsubstituted cyclopentadienyl ring are 1.420 (2) and 1.406 (3) A, respectively, and the Fe-C distances range from 2.029 (2) to 2.051 (2) A. The phenyl and unsubstituted cyclopentadienyl rings are involved in C-H.pi interactions, with intermolecular H.centroid distances of 2.85 and 3.14 A for C-H.pi(Ph), and 2.88 A for C-H.pi(Cp). In two of these interactions, the C-H bond points towards one of the ring bonds rather than towards the ring centroid. In the crystal structure, the C-H.pi interactions connect the molecules into a three-dimensional framework.

In the title compound, [Fe(C(7)H(7)O(2))(2)], the cyclopentadienyl rings and the two attached methoxycarbonyl groups, in an anti arrangement, form an extended pi-conjugated system. The Fe-C distances range from 2.035 (3) to 2.061 (3) A and the average value of the C-C bond lengths in the two cyclopentadienyl rings is 1.419 (5) A. The rings are almost parallel to one another [1.0 (2) degrees ] and are mutually twisted from an eclipsed conformation by only 1.8 (3) degrees (average value). The methoxycarbonyl groups are twisted out of the plane of the cyclopentadienyl rings by 6.5 (4) and 15.7 (4) degrees, respectively. The molecules are joined into dimers by intermolecular C-H.O hydrogen bonds that form ten-membered rings. The same types of hydrogen bonds form eight-membered rings and infinite chains along the b axis.

The structure of the title compound, Na2[Cu(CHO2)3.72(C2H3O2)0.28], is built of sodium cations and CuII complex anions; the latter are linked into infinite chains. The CuII atoms are coordinated by five O atoms belonging to five formate ligands, forming a distorted square-pyramidal coordin­ation. Four symmetry-independent formate ligands are bonded to the Cu atom with Cu—O distances in the range 1.9370 (10)–1.9886 (8) A. The fifth formate ligand, bonded to the CuII atom at a longer distance of 2.2889 (9) A, forms a bridge to the neighbouring copper(II) ion which is symmetry-related to the original ion by a twofold screw axis. Thus, infinite chains are formed along the b axis. One of the terminal formate ligands is disordered; 28.4 (13)% of its sites are occupied by acetate, which was present in the starting material and was not completely displaced in the course of the reaction.

The central CuII atom of the molecular title complex, [CuCl2(C2H3N3)4], is situated on a site with symmetry 2.22. It is six-coordinated in an elongated octahedral geometry, with the equatorial plane defined by four N atoms of four 1,2,4-triazole ligands and the axial positions occupied by two Cl atoms situated on a twofold axis. The molecules are connected via N—H...Cl hydrogen bonds and the crystal consists of two interpenetrating three-dimensional hydrogen-bonded frameworks.

The non-perovskite compound LaTi2Al9O19 was synthesized and structurally characterized by conventional X-ray powder diffraction and shown to be isostructural with SrTi3Al8O19, as confirmed by bond-valence sum calculations. The dielectric properties of LaTi2Al9O19 at 1 MHz were measured. The crystal structure of La3Ti5Al15O37, which is referred to as the most complex structure solved ab initio from X-ray powder diffraction (XRPD) to date, is shown to be incorrect.

In the binuclear title compound, [Mo2(C12H15N4O2)2Cl2O3]·H2O, the complex molecules have approximate C2 symmetry. Both MoV atoms have a distorted octahedral coordination environment with cis-positioned terminal chloride and oxide groups. The heteroscorpionate organic ligand binds to the MoV atom via an N2O donor set. The water molecule bridges two complex molecules, forming O—H...O and O—H...Cl hydrogen bonds to the acetate group and to the chloride ligands.

A new hydrogen-bonded dinuclear copper(II) coordination compound has been synthesized from the Schiff-base ligand 6-(pyridine-2-ylhydrazonomethyl)phenol (Hphp). The molecular structure of [Cu(2)(php)(2)(H(2)O)(2)(ClO(4))](ClO(4))(H(2)O) (1), determined by single-crystal X-ray diffraction, reveals the presence of two copper(II) centers held together by means of two strong hydrogen bonds, with O...O contacts of only 2.60-2.68 A. Temperature-dependent magnetic susceptibility measurements down to 3 K show that the two metal ions are antiferromagnetically coupled (J = -19.8(2) cm(-1)). This exchange is most likely through two hydrogen-bonding pathways, where a coordinated water on the first Cu, donates a H bond to the O atoms of the coordinated php at the other Cu. This strong O...H(water) bonding interaction has been clearly evidenced by theoretical calculations. In the relatively few related cases from the literature, this exchange path, mediated by a (neutral) coordinated water molecule, was not recognized.

Several copper(II) methanoato complexes, namely mononuclear [Cu(O2CH)(2)(2-mpy)(2)] (1) (2-mpy = 2- methylpyridine), binuclear [Cu-2(mu-O2CH)(4)(2-mpy)(2)] (2), and the polynuclear {[Cu(mu-O2CH)(2)(2-mpy)(2)] [Cu-2(mu- O2CH)(4)]}(n) (3) and {Na-2[Cu(mu-O2CH)(2)(O2CH)(2)][Cu-2(mu-O2CH)(4)]}(n) (4), have been synthesized. The mononuclear complex I is formed by two asymmetric chelate methanoate anions and two 2-methylpyridine molecules, giving a highly distorted 'elongated octahedral' coordination sphere. Complex I decomposes outside the mother-liquid, transforming into a regular isolated binuclear paddle-wheel complex 2 with four intra-binuclear bridging methanoates and two axial 2-mpy ligands. The polynuclear complex 3 is formed of alternate mononuclear and binuclear building blocks resembling the central cores of I and 2, but with significant differences, especially for the methanoates of the mononuclear units. The oxygen atom of the mononuclear unit in the octahedral axial position in 3 is simultaneously coordinated to the axial position of the binuclear paddle-wheel central core, thus enabling a chain type of structure. A chain of alternate mononuclear and binuclear building blocks, as in the neutral compound 3. are found as well in the ionic polymeric compound 4, though two types of bridges are found in 4, while there is only one type in 3. Namely, the axial position of the octahedral mononuclear unit in 4 is occupied by the methanoate oxygen atom that is already a part of the binuclear paddle-wheel unit, while one equatorial methanoate from the mononuclear unit serves as a triatomic bridge to the axial position of the binuclear building block. A very strong antiferromagnetic interaction is found for all the complexes with the paddle-wheel building blocks [Cu-2(mu-O2CH)(4)] 2-4 (-2J = 444-482 cm(-1)), attributed to the methanoate intra-binuclear bridges. On the other hand, this strong antiferromagnetism, found already at room temperature, reduces the intensity of the EPR S = 1 spin signals reported for the isolated paddle-wheel complex 2. For the polymeric 3, only the spin S = 1/2 signals are found in the EPR spectra, and they are assigned to the mononuclear building blocks. No signals with a clear origin are however seen in the room temperature EPR spectrum of the polymeric analogue 4, only the S = 1/2 signals in the low temperature spectra. This feature is suggested to be due to a specific influence between the adjacent S = 1 (binuclear) and S = 1/2 (mononuclear) species via their bridges.

A novel layered zincophosphate (ZnPO–MPA) was prepared by hydrothermal crystallization using 3-methylaminopropylamine (MPA) as a structure-directing agent. The structure consists of macroanion [Zn2P3O8(OH)3]2- layers which are built up of 4-membered ring channels. The channels (of about 3.7 Å diameter) arise through the connection of the neighbouring rings by two oxygen bridges. The negative charge of the layers is compensated by diprotonated MPA molecules which are stacked parallel to the ring channels. ZnPO–MPA is stable up to 300 °C. At higher temperatures MPA decomposition begins followed by a dehydration, which occurs through condensation of the framework hydroxyl groups. The activation energy of the MPA decomposition is high due to the fact that the layers and MPA cations are held together by strong hydrogen bonds. Jedan novi slojeviti cinkofosfat (ZnPO–MPA) dobijen je hidrotermalnom kristalizacijom korišćenjem 3-metilaminopropilamina (MPA) kao agensa za usmeravanje strukture. Struktura se sastoji od makroanjonskih slojeva [Zn2P3O8(OH)3]2- koji su izgrađeni od kanala u vidu četvoročlanog prstena. Kanali (prečnika oko 3,7 Å) nastaju povezivanjem susednih prstenova preko kiseoničnih mostova. Negativno naelektrisanje slojeva kompenzovano je dvoprotonovanim MPA koji su naslagani paralelno prstenastim kanalima. ZnPO–MPA je stabilan do 300 °C. Na višim temperaturama počinje razlaganje MPA koje je praćeno dehidratacijom, a ova se dešava putem kondenzacije hidroksilnih grupa rešetke. Energija aktivacije razlaganja MPA je velika zbog toga što se slojevi i katjoni MPA uzajamno drže jakim vodoničnim vezama.

A new 2D zinc phosphate [H3NCH(CH3)CH2NH3]2+ 0.75[COOH(CH2)COOH]0.25(Zn3P3O11OH)2- * 0.5NH4 + consists of zinc phosphate layers, which are intercalated by diprotonated 1,2-diaminopropane, malonic acid, and NH4 + ions. The inorganic layers are composed of alternating ZnO4 and PO4 (PO3OH) tetrahedra that form 8-membered ring apertures. The intercalated species strongly interact with the zinc phosphate layers through hydrogen bonds, which is a key factor in stabilizing the structure. Crystal data: monoclinic, P21/a, a = 8.3457(1) Å, b = 16.8953(3) Å, c = 10.1817(2) Å, β = 95.3121(8)°, Z = 4, R = 0.0423.

Crystal structure analysis of the title compound, C(13)H(12)ClNO, reveals three crystallographically independent molecules in the asymmetric unit. The main conformational difference between these molecules is the orientation of the phenyl rings with respect to the pyrrole rings. The coplanar arrangement of the aldehyde groups attached to the pyrrole rings influences the pyrrole-ring geometry. The C2-C3 and N1-C5 bonds are noticeably longer than the C4-C5 and N1-C2 bonds. Two independent molecules of the title compound form dimers via intermolecular C-H.O hydrogen bonds [D.A = 3.400 (3) A and D-H.A = 157 degrees ]. The perpendicular orientation of the phenyl and pyrrole rings of one independent molecule and its symmetry-related molecule allows C-H.pi interactions, with an H.centroid distance of 2.85 A and a C-H.pi angle of 155 degrees. The distances between the H atom and the pyrrole-ring atoms indicate that the C-H bond points towards one of the bonds in the pyrrole ring.

The central CuIIatom of the molecular title complex, [CuCl2(C2H3N3)4], is situated on a site with symmetry 2.22. It is six-coordinated in an elongated octahedral geometry, with the equatorial plane defined by four N atoms of four 1,2,4-triazole ligands and the axial positions occupied by two Cl atoms situated on a twofold axis. The molecules are connectedviaN—H...Cl hydrogen bonds and the crystal consists of two interpenetrating three-dimensional hydrogen-bonded frameworks.

Background Several papers described the structure of curcumin and some other derivatives in solid and in solution. In the crystal structure of curcumin, the enol H atom is located symmetrically between both oxygen atoms of the enolone fragment with an O···O distance of 2.455 Å, which is characteristic for symmetrical H-bonds. In the solution, the geometry of the enolone fragment is attributed to the inherent disorder of the local environment, which solvates one of the basic sites better than the other, stabilizing one tautomer over the other. In this paper, how the position of methoxy groups in dimethoxy curcuminoids influence the conformation of molecules and how the halogen atoms change it when they are bonded at α-position in keto-enol part of molecules is described. Results Six isomers of dimethoxy curcuminoids were prepared. Conformations in solid state, which were determined by X-ray single crystallography and 1H MAS and 13C CPMAS NMR measurements, depend on the position of methoxy groups in curcuminoid molecules. In solution, a fast equilibrium between both keto-enol forms exists. A theoretical calculation finding shows that the position of methoxy groups changes the energy of HOMO and LUMO. An efficient protocol for the highly regioselective bromination and chlorination leading to α-halogenated product has been developed. All α-halogenated compounds are present mainly in cis keto-enol form. Conclusions The structures in solid state of dimethoxy curcuminoids depend on the position of methoxy groups. The NMR data of crystalline solid samples of 3,4-diOCH3 derivative, XRD measurements and X-ray structures lead us to the conclusion that polymorphism exists in solids. The same conclusion can be done for 3,5-diOCH3 derivative. In solution, dimethoxy curcuminoids are present in the forms that can be described as the coexistence of two equivalent tautomers being in fast equilibrium. The position of methoxy groups has a small influence on the enolic hydrogen bond. Theoretical calculations show that the energy gap between HOMO and LUMO depend on the position of methoxy groups and are lower in solution. Chlorination and bromination on α-position of 1,3-diketone moiety do not change the preferential form being cis keto-enol as in parent compounds.