mer‐Di­aqua­bis(1H‐imidazole‐κN3)(orotato‐κ2N3,O4)­nickel(II)

The title mononuclear complex, [Ni(C₅H₂N₂O₄)(C₃H₄N₂)₂(H₂O)₂] or [Ni(HOr)(im)₂(H₂O)₂] (im is imidazole and H₃Or is orotic acid, or 2,6‐dioxo‐1,2,3,6‐tetra­hydro­pyrimidine‐4‐carboxylic acid), has been synthesized and the crystal structure determination is reported. The Ni^II ion in the complex has a distorted octahedral coordination geometry comprised of one deprotonated pyrimidine N atom and the adjacent carboxyl­ate O atom of the orotate ligand, two tertiary imidazole N atoms and two aqua ligands. An extensive three‐dimensional network of OW—H⋯O and N—H⋯O hydrogen bonds, and π–π and π–ring interactions are responsible for crystal stabilization.     

Bis(5‐hydroxy‐2‐hydroxy­methyl‐4‐pyrone‐κ2O4,O5)bis(2‐hydroxy­methyl‐5‐oxido‐4‐pyrone‐κ2O4,O5)­calcium(II) tetrahydrate

In the title compound, [Ca(C₆H₅O₄)₂(C₆H₆O₄)₂]·4H₂O, which is a kojic acid–Ca²⁺ complex, the Ca atom is on a twofold axis and is octacoordinated by O atoms from four pyrone ligand mol­ecules. The hydroxyl and ketone O atoms of each ligand form a five‐membered chelate ring with the Ca atom. The crystal structure is stabilized by partial stacking and O—H?O hydrogen bonds.     

Synthesis,Spectrothermal Behaviour and Molecular Structure of Aquaorotatotriethanolaminenickel(II) Monohydrate

The aquaorotatotriethanolaminenickel(II) monohydrate, [Ni(HOr)(H₂O)(tea)]·H₂O ( 1 ), was synthesized and characterized by means of elementel analysis, IR and UV‐Vis, spectroscopy, magnetic susceptibility, thermal analysis and X‐ray diffraction techniques. The nickel ion in [Ni(C₅H₂N₂O₄)(H₂O)(N(C₂H₄OH)₃)] is chelated to the deprotonated N3 pyrimidine atom and to the carboxylate oxygen atom of the bidentate orotate dianion, and to the one nitrogen and two oxygen atoms of the tridentate triethanolamine molecule and its octahedral geometry is completed by an aqua ligand. It crystallizes in the monoclinic system, space group P2₁/c with lattice parameters a = 7.1528(5) Å, b = 19.4903(14) Å, c = 11.8085(8) Å, β = 106.237(5)°, V = 1580.55(19) ų, Z = 4. An extensive three dimensional network of O_w‐H…O, N‐H…O and O‐H…O hydrogen bonds, π‐π and π‐ring interactions are responsible for crystal stabilization. The decomposition reaction take places in the temperature range 20‐1000 °C in the static air atmosphere. Thermal decomposition of 1 proceeds in three stages.     

Vitamin B13 Complexes of Nickel(II) and Copper(II) with Ethanolamine: Syntheses,Crystal Structures,Spectroscopic and Thermal Studies

Fac‐bis(ethanolamine)orotatonickel(II), [Ni(HOr)(ea)₂] and mer‐bis(ethanolamine)orotatocopper(II) dihydrate, [Cu(HOr)(ea)₂]· 2H₂O were synthesized and characterized by elemental analysis, FT‐IR, UV‐Vis Spectroscopy and thermal analysis. In addition, their solid‐state structures were determined by single crystal X‐ray diffraction studies. Both the fac‐[Ni(HOr)(ea)₂] (1) and mer‐[Cu(HOr)(ea)₂]·2H₂O (2) complexes are isomorphous and crystallize in the triclinic space group . The Ni²⁺ and Cu²⁺ ions are coordinated by two neutral ea ligands and one orotate dianion in a distorted octahedral fashion. The ea ligand acts as a bidentate donor through the amine N and hydroxyl O atoms, while orotate dianion is coordinated through deprotonated N3 pyrimidine atom and carboxylate oxygen atom as a bidentate ligand. Thermal decompositions of the complexes are studied in over the range 20–600 °C on heating in a static air atmosphere.     

catena‐Poly­[[[aqua(2‐methyl‐4‐oxo‐4H‐pyran‐3‐olato‐κO3,O4)copper(II)]‐μ‐chloro] monohydrate]

In the title complex, {[Cu(C₆H₅O₃)Cl(H₂O)]·H₂O}_n, the Cu^II atom has a deformed square‐pyramidal coordination geometry formed by two O atoms of the maltolate ligand, two bridging Cl atoms and the coordinated water O atom. The Cu atoms are bridged by Cl atoms to form a polymeric chain. The deprotonated hydroxyl and ketone O atoms of the maltolate ligand form a five‐membered chelate ring with the Cu atom. Stacking interactions and hydrogen bonds exist in the crystal.     

trans‐Bis(dimethyl sulfoxide‐κO)bis(3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylato‐κ2N1,O2)copper(II)

The title compound, [Cu(C₉H₅N₂O₃)₂(C₂H₆OS)₂], consists of octahedrally coordinated Cu^II ions, with the 3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylate ligands acting in a bidentate manner [Cu—O = 1.9116 (14) Å and Cu—N = 2.1191 (16) Å] and a dimethyl sulfoxide (DMSO) molecule coordinated axially via the O atom [Cu—O = 2.336 (5) and 2.418 (7) Å for the major and minor disorder components, respectively]. The whole DMSO molecule exhibits positional disorder [0.62 (1):0.38 (1)]. The octahedron around the Cu^II atom, which lies on an inversion centre, is elongated in the axial direction, exhibiting a Jahn–Teller effect. The ligand exhibits tautomerization by H‐atom transfer from the hydroxyl group at position 3 to the N atom at position 4 of the quinoxaline ring of the ligand. The complex molecules are linked through an intermolecular N—H...O hydrogen bond [N...O = 2.838 (2) Å] formed between the quinoxaline NH group and a carboxylate O atom, and by a weak intermolecular C—H...O hydrogen bond [3.392 (11) Å] formed between a carboxylate O atom and a methyl C atom of the DMSO ligand. There is a weak intramolecular C—H...O hydrogen bond [3.065 (3) Å] formed between a benzene CH group and a carboxylate O atom.     

Syntheses,Spectra, Thermal Studies and Crystal Structures of Vitamin B13 Complexes of Nickel(II) with N,N,N′,N′‐Tetramethylethylenediamine and 2,2‐Dimethylpropane‐1,3‐diamine

Two nickel(II) complexes of vitamin B13 (H₃Or) with N,N,N′,N′‐tetramethylethylenediamine (tmen) and 2,2‐dimethylpropane‐1,3‐diamine (dmpen) were synthesized and characterized by means of elemental and thermal analyses, magnetic susceptibility, and IR and UV/Vis spectroscopic studies. The crystal structures of mer‐[Ni(HOr)(H₂O)₂(tmen)] · H₂O ( 1 ) and [Ni(HOr)(dmpen)₂] ( 2 ) were determined by using single‐crystal X‐ray diffraction. In the complexes, which crystallize in the triclinic system (space group for 1 ) and the monoclinic system (space group P2₁/c for 2 ), the Ni^II ions exhibit a distorted octahedral coordination. Ni^II ions are chelated by the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group, the distorted octahedral coordination completed by one tmen and two aqua ligands for 1 or two dmpen ligands for 2 .     

Bis(methanol‐κO)dioxido[3,3′‐(1H‐1,2,4‐triazole‐3,5‐diyl)diphenolato‐κ3O,N4,O′]uranium(VI) methanol monosolvate

The structure of the title compound, [U(C₁₄H₉N₃O₂)O₂(CH₃OH)₂]·CH₃OH, is the first to be reported for an actinide complex including triazole ligands. The U^VI atom exhibits a pentagonal–bipyramidal NO₆ coordination environment, involving two axial oxide ligands [U=O = 1.766 (3) and 1.789 (3) Å], four equatorial O atoms [U—O = 2.269 (3)–2.448 (3) Å] from the ligand and the two coordinated methanol molecules, and one equatorial N atom [U—N = 2.513 (4) Å] from the ligand. In the crystal structure, the complex molecules are linked via intermolecular N—H...O and O—H...O hydrogen bonds to form a two‐dimensional structure.     

Bis­[bis­(pyrimidin‐2‐yl‐κN)­amine](dicyan­amido‐κN1)(tri­fluoro­methanesulfonato‐κO)copper(II) ethanol hemisolvate forms a hydrogen‐bonded chain

In the crystal structure of [Cu(CF₃SO₃)(C₂N₃)(C₈H₇N₅)₂]·0.5C₂H₆O, the Cu^II atom adopts a distorted octahedral geometry, with the basal plane formed by two N atoms of one dipyrimidinyl­amine ligand, one N atom of the second pyrimidine ligand and a nitrile N atom of the dicyan­amide anion [Cu—N = 1.972 (2)–2.021 (2) Å]. The apical positions are occupied by an N atom of the second ligand [Cu—N = 2.208 (2) Å], and an O atom of the tri­fluoro­methane­sulfonate anion [Cu—O = 2.747 (2) Å] at a semi‐coordination distance. Pairs of inversion‐related N—H⋯N hydrogen bonds of the so‐called Watson–Crick type, augmented by two C—H⋯N contacts, link adjacent complexes into an infinite one‐dimensional chain running in the [101] direction.     

Acetato(N‐phenylpyridine‐2‐carboxamidato‐κ2N,N)(N‐phenylpyridine‐2‐carboxamide‐κ2N1,O)copper(II)

The title complex, [Cu(C₁₂H₉N₂O)(C₂H₃O₂)(C₁₂H₁₀N₂O)], is a neutral Cu^II complex with a primary N₃O₂ coordination sphere. The Cu centre coordinates to both a deprotonated and a neutral molecule of N‐phenylpyridine‐2‐carboxamide and also to an acetate anion. The coordination around the metal centre is asymmetric, the deprotonated ligand providing two N donor atoms [Cu—N = 1.995 (2) and 2.013 (2) Å] and the neutral ligand providing one N and one O donor atom to the coordination environment [Cu—N = 2.042 (2) Å and Cu—O = 2.2557 (19) Å], the fifth donor being an O atom of the acetate ion [Cu—O = 1.9534 (19) Å]. The remaining O atom from the acetate ion can be considered as a weak donor atom [Cu—O = 2.789 (2) Å], conferring to the Cu complex an asymmetric octahedral geometry. The crystal structure is stabilized by intermolecular N—H...O, C—H...O and C—H...π interactions.     

Synthesis, spectroscopic, thermal Studies, antimicrobial activities and crystal structures of Co(II), Ni(II), Cu(II) and Zn(II)-orotate complexes with 2-methylimidazole

The 2-methylimidazole complexes of Co(II), Ni(II), Cu(II) and Zn(II) orotates, mer-[Co(HOr)(H₂O)₂(2-meim)₂] (1), mer-[Ni(HOr)(H₂O)₂(2-meim)₂] (2), [Cu(HOr)(H₂O)₂(2-meim)] (3) and [Zn(HOr)(H₂O)₂(2-meim)] (4), were synthesized and characterized by elemental analysis, spectral (UV–Vis and FT-IR) methods, thermal analysis (TG, DTG and DTA), magnetic susceptibility, antimicrobial activity studies and single crystal X-ray diffraction technique. The complexes 1 and 2 have distorted octahedral geometries with two monodentate 2-methylimidazole and one bidentate orotate and two aqua ligands. The complexes 3 and 4 have distorted square pyramidal and trigonal bipyramidal geometry, respectively, with one 2-methylimidazole, bidentate orotate and aqua ligands. The orotate coordinated to the metal(II) ions through deprotonated nitrogen atom of pyrimidine ring and oxygen atom of carboxylate group as a bidentate ligand. The antimicrobial activities of 1 and 4 were found to be more active gram (+) than gram (−) and 4 could be use for treatment Staphylococcus aureus.     

Co(II), Ni(II) and Zn(II)-orotate complexes with N-methylimidazole: Synthesis, crystal structures and antimicrobial activities

Three Co(II), Ni(II) and Zn(II) complexes of orotate with the N-methylimidazole ligand were synthesized and characterized by means of elemental and thermal analysis, magnetic susceptibilities, IR, UV-Vis spectroscopic and antimicrobial activity studies. The crystal structures of [Co(HOr)(H₂O)₂(Nmeim)₂]₃·H₂O (1), [Ni(HOr)(H₂O)₂(Nmeim)₂] (2) and [Zn(HOr)(H₂O)(Nmeim)₂] (3) were determined by the single crystal X-ray diffraction technique (H₃Or = orotic acid and Nmeim = N-methylimidazole). In complexes 1 and 2, the Co(II) and Ni(II) ions have distorted octahedral geometries with two Nmeim, one orotate and two aqua ligands. Complex 3 has a distorted trigonal bipyramidal geometry with two N-methylimidazole, one orotate and one aqua ligands. In the complexes, the orotate is coordinated to the metal(II) ions through the deprotonated nitrogen atom of the pyrimidine ring and the oxygen atom of the carboxylate group as a bidentate ligand. The complexes form a three-dimensional framework by hydrogen bonding, C-H?π and π?π stacking interactions. The MIC values of the complexes against selected microorganisms were determined to be in range 300-2400 μg/mL.     

Methyl β‐d‐galactopyranosyl‐(1→4)‐β‐d‐allopyranoside tetrahydrate

The title compound, C₁₃H₂₄O₁₁·4H₂O, (I), crystallized from water, has an internal glycosidic linkage conformation having ϕ′ (O5_Gal—C1_Gal—O1_Gal—C4_All) = −96.40 (12)° and ψ′ (C1_Gal—O1_Gal—C4_All—C5_All) = −160.93 (10)°, where ring‐atom numbering conforms to the convention in which C1 denotes the anomeric C atom, C5 the ring atom bearing the exocyclic hydroxymethyl group, and C6 the exocyclic hydroxymethyl (CH₂OH) C atom in the βGalp and βAllp residues. Internal linkage conformations in the crystal structures of the structurally related disaccharides methyl β‐lactoside [methyl β‐d ‐galactopyranosyl‐(1→4)‐β‐d ‐glucopyranoside] methanol solvate [Stenutz, Shang & Serianni (1999). Acta Cryst. C 55 , 1719–1721], (II), and methyl β‐cellobioside [methyl β‐d ‐glucopyranosyl‐(1→4)‐β‐d ‐glucopyranoside] methanol solvate [Ham & Williams (1970). Acta Cryst. B 26 , 1373–1383], (III), are characterized by ϕ′ = −88.4 (2)° and ψ′ = −161.3 (2)°, and ϕ′ = −91.1° and ψ′ = −160.7°, respectively. Inter‐residue hydrogen bonding is observed between O3_Glc and O5_Gal/Glc in the crystal structures of (II) and (III), suggesting a role in determining their preferred linkage conformations. An analogous inter‐residue hydrogen bond does not exist in (I) due to the axial orientation of O3_All, yet its internal linkage conformation is very similar to those of (II) and (III).     

Tris(8‐quinolinolato‐N,O)­cobalt(III) ethanol solvate

In the crystal of the title complex, [Co(C₉H₆NO)₃]·C₂H₅OH, the central Co atom has a distorted octahedral coordination comprised of three N atoms and three O atoms from the three 8‐quinolinolato ligands. The three Co—O bond distances are in the range 1.887 (2)–1.910 (2) Å, while the three Co—N bond distances range from 1.919 (2) to 1.934 (2) Å. The solvent ethanol mol­ecule forms an intermolecular O—H?O hydrogen bonding with a quinolinolato ligand.     

Supramolecular Assemblies of Mononuclear and Polymeric Nickel(II) Glutarato Complexes via π‐π Stacking Interactions and Hydrogen Bonds: [Ni(H2O)3(phen)(C5H6O4)] · H2O and [Ni(H2O)2(phen)(C5H6O4)]

Syntheses of the sky blue complex compounds [Ni(H₂O)₃(phen)(C₅H₆O₄)] · H₂O ( 1 ) and [Ni(H₂O)₂(phen)(C₅H₆O₄)] ( 2 ) were carried out by the reactions of 1,10‐phenanthroline monohydrate, glutaric acid, NiSO₄ · 6 H₂O and Na₂CO₃ in CH₃OH/H₂O at pH = 6.9 and 7.5, respectively. The crystal structure of 1 (P 1 (no. 2), a = 14.289 Å, b = 15.182 Å, c = 15.913 Å, α = 67.108°, β = 87.27°, γ = 68.216°, V = 2934.2 ų, Z = 2) consists of hydrogen bonded [Ni(H₂O)₃‐ (phen)(C₅H₆O₄)]₂ dimers and H₂O molecules. The Ni atoms are octahedrally coordinated by two N atoms of one phen ligand, three water O atoms and one carboxyl O atom from one monodentate glutarato ligand (d(Ni–N) = 2.086, 2.090 Å; d(Ni–O) = 2.064–2.079 Å). Through the π‐π stacking interactions and intermolecular hydrogen bonds, the dimers are assembled to form 2 D layers parallel to (0 1 1). The crystal structure of 2 (P2₁/n (no. 14), a = 7.574 Å, b = 11.938 Å, c = 18.817 Å, β = 98.48°, V = 1682.8 ų, Z = 4) contains [Ni(H₂O)₂(phen)(C₅H₆O₄)_2/2] supramolecular chains extending along [010]. The Ni atoms are octahedrally coordinated by two N atoms of one phen ligand, two water O atoms and two carboxyl O atoms from different bis‐monodentate glutarato ligands with d(Ni–N) = 2.082, 2.105 Å and d(Ni–O) = 2.059–2.087 Å. The supramolecular chains are assembled into a 3 D network by π‐π stacking interactions and interchain hydrogen bonds. A TG/DTA of 2 shows two endothermic effects at 132 °C and 390 °C corresponding to the complete dehydration and the lost of phen.     

Thermoanalytical Investigation of Magnesium(II) Complexes with Nicotinamide as Bio-Active Ligand

The stoichiometry of thermal decomposition was studied for the following Mg(II) nicotinamide (NA) complexes: Mg(Ac)₂(NA)₅·2H₂O (I), Mg(CIAc)₂(NA)₆·6H₂O (II), Mg(Cl₂Ac)₂(NA)₆·5H₂O (III) and Mg(Cl₃Ac)₂(NA)₆·2H₂O (IV), where Ac=CH₃COO⁻, ClAc=ClCH₂COO⁻, Cl₂Ac=Cl₂CHCOO⁻ and Cl₃Ac=Cl₃CCOO⁻. Heating the compounds results first in the release of water molecules. The NA molecules are released in one step (complexes II and III) or in two steps (complexes I and IV). The compositions of the complexes, the solid-state intermediates and the products of thermolysis were identified by means of elemental analysis and complexometric titration. The results reveal that MgO is left as residue at the end of thermal degradation of compounds I–IV, NA is coordinated to Mg(II) through the nitrogen atom of the heterocyclic ring. The IR data indicate unidentate coordination of the carboxylate ions to the Mg(II) in complexes I–IV. This revised version was published online in August 2006 with corrections to the Cover Date.     

Photomagnetic Switching of Heterometallic Complexes [M(dmf)4(H2O)3(μ‐CN)Fe(CN)5]⋅H2O (M=Nd,La, Gd,Y) Analyzed by Single‐Crystal X‐ray Diffraction and Ab Initio Theory

Single‐crystal X‐ray diffraction measurements have been carried out on [Nd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 1 ; dmf=dimethylformamide), [Nd(dmf)₄(H₂O)₃(μ‐CN)Co(CN)₅]?H₂O ( 2 ), [La(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 3 ), [Gd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 4 ), and [Y(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 5 ), at 15(2) K with and without UV illumination of the crystals. Significant changes in unit‐cell parameters were observed for all the iron‐containing complexes, whereas 2 showed no response to UV illumination. Photoexcited crystal structures have been determined for 1 , 3 , and 4 based on refinements of two‐conformer models, and excited‐state occupancies of 78.6(1), 84(6), and 86.6(7) % were reached, respectively. Significant bond‐length changes were observed for the Fe–ligand bonds (up to 0.19 Å), the cyano bonds (up to 0.09 Å), and the lanthanide–ligand bonds (up to 0.10 Å). Ab initio theoretical calculations were carried out for the experimental ground‐state geometry of 1 to understand the electronic structure changes upon UV illumination. The calculations suggest that UV illumination gives a charge transfer from the cyano groups on the iron atom to the lanthanide ion moiety, {Nd(dmf)₄(H₂O)₃}, with a distance of approximately 6 Å from the iron atom. The charge transfer is accompanied by a reorganization of the spin state on the {Fe(CN)₆} complex, and a change in geometry that produces a metastable charge‐transfer state with an increased number of unpaired electrons, thus accounting for the observed photomagnetic effect.     

μ‐Oxo‐bis{[(6‐hydroxy­methyl‐2‐pyridyl­methyl)­bis(2‐pyridyl­methyl)­amine‐κ5N,N′,N′′,N′′′,O]­iron(III)} tetrakis­(perchlorate)

The novel μ‐oxo‐diiron complex [Fe₂O(BPHPA)₂](ClO₄)₄ [BPHPA is (6‐hydroxy­methyl‐2‐pyridyl­methyl)­bis(2‐pyridyl­methyl)­amine, C₁₉H₂₀N₄O], contains a binuclear centrosymmetric [Fe₂O(BPHPA)₂]⁴⁺ cation (the bridging O atom lies on an inversion centre) and four perchlorate anions. Each iron ion is coordinated by four N atoms [Fe—N = 2.117 (5)–2.196 (5) Å] and one O atom [Fe—O = 2.052 (5) Å] from a BPHPA ligand, and by one bridging oxo atom [Fe—O = 1.7896 (9) Å], forming a distorted octahedron. There are hydrogen bonds between the hydroxy group and perchlorate O atoms [O—H·O = 2.654 (7) Å].     

A novel two‐dimensional coordination polymer: poly[diaquatetra‐μ2‐chlorido‐[μ2‐2,2′‐(piperazine‐1,4‐diium‐1,4‐diyl)diacetate]dicadmium(II)]

In the crystal structure of the title two‐dimensional metal–organic polymeric complex, [Cd₂Cl₄(C₈H₁₄N₂O₄)(H₂O)₂]_n, the asymmetric unit contains a crystallographically independent Cd^II cation, two chloride ligands, an aqua ligand and half a 2,2′‐(piperazine‐1,4‐diium‐1,4‐diyl)diacetate (H₂PDA) ligand, the piperazine ring centroid of which is located on a crystallographic inversion centre. Each Cd^II centre is six‐coordinated in an octahedral environment by an O atom from an H₂PDA ligand and an O atom from an aqua ligand in a trans disposition, and by four chloride ligands arranged in the plane perpendicular to the O—Cd—O axis. The complex forms a two‐dimensional layer polymer containing [CdCl₂]_n chains, which are interconnected into an extensive three‐dimensional hydrogen‐bonded network by C—H...O, C—H...Cl and O—H...O hydrogen bonds.     

Bis{μ‐2‐[(1,5‐diaza‐1‐cyclooctyl)methyl]phenolato‐N,N′,O:O}bis[chlorozinc(II)] diacetone solvate: design of a square‐pyramidal ZnN2O2Cl complex

The title complex, [Zn₂(C₁₃H₁₉N₂O)₂Cl₂]·2C₃H₆O, resides on a crystallographic inversion center. The two Zn^II centers bridged by the phenoxo groups are in pentacoordinated distorted square‐pyramidal coordination environments with an intramolecular Zn?Zn distance of 3.175 (3) Å. The mesocyclic ligand takes a boat–chair conformation and an H atom from the 1,5‐di­aza­cyclo­octane ring effectively blocks the axial coordination site opposite the Cl ligand to form the ZnN₂O₂Cl geometry. The crystal structure is stabilized by a N—H?O hydrogen bond between the amino group and an acetone mol­ecule.