Catenated polymeric molecular patterns in structures of two calcium(II) complexes with pyridine-2,3-dicarboxylate (quinolinic) and water ligands

The structure of triclinic catena-tetraquo(μ-pyridine-2,3-dicarboxylato-N,O; O′)calcium(II) is composed of two symmetry independent Ca(II) ions and two independent ligand molecules. Each Ca(II) is coordinated by a N,O-bonding moiety of a ligand, four water oxygens, and a carboxylate oxygen donated by an adjacent bridging ligand. The resulting molecular ribbons are propagating in the [010] crystal direction. Both Ca(II) ions are eight coordinate forming a capped pentagonal bipyramidal with strongly distorted pentagonal equatorial planes. Hydrogen bonds between carboxylate oxygens and coordinated waters are responsible for the stability of the structure. The orthorhombic structure of catena-trisaquo[(μ-2, 3-dicarboxypyridin-1-ium-O,O′; O′′) (H pyridine-2,3-dicarboxylato-N,O)]calcium(II) is composed of molecular ribbons in which the bridging of Ca(II) ions occurs through a ligand using one bidentate carboxylate. The other carboxylate of this ligand donates only one O atom to Ca(II), the second remaining inactive. A proton is attached to the hetero-nitrogen. Each Ca(II) is also chelated by a N,O-bonding moiety of a second ligand, which does not bridge and its second carboxylate remains protonated. Three water oxygen atoms complete the coordination around the Ca(II) ion to eight. The resulting coordination polyhedron is a capped pentagonal bipyramid with a strongly distorted equatorial plane. Hydrogen bonds in which coordinated waters act as donors are responsible for the stability of the structure.     

Crystal structure of a calcium(II) complex with pyrazine-2,3-dicarboxylate,nitrate and water ligands

The structure of catena-[tris(aquo-O)(nitrato-O,O′)(µ-hydrogen pyrazine-2,3-dicarboxylato-O,N–O′,N′)calcium(II)][tetra(aquo-O)(μ-hydrogen pyrazine-2,3-dicarboxylato-O,N–O′,N′) calcium(I)] nitrate, {Ca[H(2,3-PZDC)](H₃O)₃(NO₃)}{Ca[H(2,3-PZDC)](H₂O)₄}⁺ (NO₃)^?, is composed of molecular ribbons in which calcium atoms are bridged by both N,O-bonding moieties of singly deprotonated ligand molecules. The hydrogen atom donated by one carboxylic group is linked by a short intramolecular hydrogen bond of 2.37 Å to an oxygen atom of the second carboxylic group of the same ligand. Two crystallographically independent Ca(II) ions exhibit different coordination modes. One is coordinated by two bonding moieties of the bridging ligand molecules, three water oxygen atoms and two oxygen atoms of a nitrate ligand. The other calcium ion is chelated by two bonding moieties donated by the bridging ligand molecules and four water oxygen atoms, forming a positively charged assembly with a nitrate anion located nearby. The coordination polyhedron of the first calcium ion is a strongly deformed bicapped pentagonal bipyramid with nine-coordinated atoms; the second calcium ion is also in a strongly deformed pentagonal bipyramid with one apex on one side of the equatorial plane and two apices on the other. Coordinated water oxygen atoms act as donors in a hydrogen-bond network.     

Doubly bridged molecular ribbons in the structure of an ionic complex,hydronium zinc(II) pyrazine-2,3-dicarboxylate

The structure of dihydronium [catena-bis(μ-pyrazine-2,3-dicarboxylato-N,O,O′)zinc(II)], (H3O)2[Zn(2,3PZDC)2], is composed of polyanionic ribbons of zinc(II) ions linked by double bridging 2,3-PZDC ligand molecules. Each ligand uses an N,O bonding moiety formed by one carboxylic group [Zn–O 2.071(2)?Å; Zn–N 2.184(2)?Å] and a monodentate oxygen atom of the other carboxylate group [Zn–O 2.092(2)?Å]. Coordination around the zinc(II) ion is strongly distorted octahedral. Hydronium cations (H₃O)¹⁺ link the ribbons by hydrogen bonds.     

Crystal structures of two Ca(II) complexes with imidazole-4,5-dicarboxylate and water ligands

The structure of compound I: poly-diaqua(μ-imidazole-4,5-dicarboxylato-N,O; -O′; -O′′, -O′′′) calcium(II) monohydrate [Ca(C₅H₂N₂O₄)(H₂O)₂·H₂O] is built of molecular sheets in which imidazole-4,5-dicarboxylate ligands bridge the metal ions using both carboxylate groups, each bidentate. Ca(II) is coordinated by six oxygen atoms and one hetero-ring nitrogen atom distributed at the apices of a capped tetragonal bipyramid. The basal plane of the pyramid is formed by two carboxylate oxygen atoms [d(Ca–O2?=?2.374(1)?Å, d(Ca–O4)?=?2.412(1)?Å] and two water oxygen atoms [d(Ca–O5)?=?2.384(1)?Å, d(Ca–O6)?=?2.455(1)?Å], the capped position is occupied by the carboxylate oxygen atom O3 [d(Ca–O3)?=?2.325(1)?Å], the hetero-ring nitrogen atom [d(Ca–N2)?=?2.523(1)?Å] and the carboxylate oxygen atom O4 [d(Ca–O2)?= 2.412(1)?Å] form the apices of the prism. The solvation water molecule plays a significant role in a framework of hydrogen bonds responsible for the stability of the crystal. The structure of compound II: trans-tetraquadi(H-imidazole-4,5-dicarboxylato-N,O) calcium(II) monohydrate, [Ca(C₅H₃N₂O₄)₂(H₂O)₄·H₂O] consists of monomers in which the Ca(II) ion is located on a centre of symmetry. The coordination around the Ca(II) is a strongly deformed pentagonal bipyramidal with the imidazole-4,5-dicarboxylate (4,5-IDA) ligands in the trans arrangement forming a dihedral angle of 68.3°. An imidazole-ring nitrogen atom [d(Ca–N)?=?2.632(2)?Å] and one carboxylate O atom [d(Ca–O)?=?2.531(2)?Å] from each ligand coordinate to the metal ion. The coordination is completed by four water oxygen atoms [d(Ca–O)?=?2.393(2)?Å] and [d(Ca–O)?=?2.367(2)?Å]. The coordinated water molecules act as hydrogen bond donors and acceptors to the unbonded carboxylate oxygen atoms in adjacent monomers giving rise to a three-dimensional molecular network.     

Molecular sheets in the crystal structure of a Ba(II) complex with imidazole-4,5-dicarboxylate and water ligands

The structure of poly-tetraaquabis(μ-Himidazole-4,5-dicarboxylato-N,O;-O′)barium(II) dihydrate, Ba(C₅H₃N₂O₄)₂(H₂O)₄·2H₂O is built of molecular sheets in which singly-deprotonated imidazole-4,5-dicarboxylate [H(4,5-IDA)] bridges metal ions using its N, O bonding moiety and one oxygen atom of its second carboxylate group. Each barium(II) is coordinated by N, O bonding moieties of two ligands, two carboxylate oxygen atoms of two other ligands and four waters. The coordination number of Ba(II) is ten, and the coordination polyhedron contains fourteen faces. A network of hydrogen bonds is responsible for the stability of the crystal.     

The Crystal and Molecular Structure of a New Calcium(II) Complex with Pyridine-2,6-DiCarboxylate,Water and Nitrate Ligands

Crystals of {catena-[μ-aqua-O]bis[μ-pyridine-2,6-dicarboxylato-O,N-O']} {[monoaqua-nitrato, O-calcium(II)] [diaqua-calcium(II)]} contain dimeric units composed of two calcium(II) ions and two ligand molecules, in which the calcium ions are bridged by two bidentate oxygen atoms, each donated by one carboxylic group of the ligand. The Ca(II) ion is also coordinated by one oxygen atom of the second carboxylate group and the hetero-ring nitrogen atom belonging to the same ligand molecule. The dimers form molecular chains through protons situated at the symmetry centers halfway between the non-bridging carboxylate oxygen atoms. In addition, both calcium ions in the dimer are bridged to calcium ions in adjacent dimers - each by a pair water oxygen molecules giving rise to two-dimensional molecular sheets. Coordination of the Ca ion in the dimer is completed either by two water oxygen atoms or by one water oxygen atom and an oxygen atom donated by a nitrate group. The molecular sheets are held together by an extended system of hydrogen bonds.     

The Crystal and Molecular Structures of Pb(II) Complexes with Furan-2-Carboxylate and Furan-3-Carboxylate Ligands

The crystals of Pb(II) 2-furancarboxylate (title compound I) contain tetrameric structural units Pb₄(2-FCA)₈(H₂O₂) in which four Pb(II) ions are bridged by carboxylate oxygen atoms forming a circular moiety. In addition, pairs of Pb(II) ions are bridged by carboxylate oxygen atoms inside this moiety. The molecular pattern observed in Pb(II) 3-furancarboxylate (title compound II) is polymeric. It consists of Pb(3-FCA)₂(H₂O) structural units bridged by carboxylate oxygen atoms donated by the furan-3-carboxylate (3-FCA) ligands which are bidentate, using both their carboxylate oxygen atoms for chelation. The coordination around Pb(II) ions is eightfold and ninefold including, apart from carboxylate oxygen atoms, a water oxygen atom and oxygen atoms donated by the furan rings of the ligand molecules. Hydrogen bonds with the water molecule as the donor operate between adjacent ligand molecules. The stereochemical activity of the lone 6s ² electron pair on the Pb(II) is observed in title compound II.     

The Crystal Structures of Two Polymorphic Forms of a Calcium(II) Complex with Pyridine-2,6-Dicarboxylate,Water and Nitrate Ligands

The calcium (II) complex: catena-mono(μ-pyridine-2,6-dicarboxylato-O:O:N;O') (diaqua-O)mono (nitrato-O:O)calcium(II) exists in two polymorphic forms. Each contains molecular ribbons in which adjacent Ca(II) ions are bridged by monodentate oxygen atoms donated by one carboxylate group of the pyridine-2,6-carboxylate ligand. Apart from this bridging oxygen atom, the Ca(II) ion is coordinated by two carboxylate oxygen atoms contributed by a different carboxylate group of the ligand molecule, the heteroring nitrogen atom, two water oxygen atoms and two oxygen atoms of a nitrate group giving rise to a distorted pentagonal bipyramid as a coordination polyhedron. The structures of the polymorphic modifications differ in the way in which the nitrate ligands are oriented with respect to the equatorial planes of the adjacent Ca(II) coordination polyhedra: the trans mode in the α-form; the cis mode in the β-form. In both forms, hydrogen bonds operate between the carboxylate oxygen atoms, water oxygen atoms and nitrate oxygen atoms.     

POLYMERIC MOLECULAR PATTERN IN THE CRYSTALS OF A CALCIUM(II) COMPLEX WITH PYRIDINE-3,4-DICARBOXYLATE AND WATER LIGANDS

Abstract

Crystals of triaquamono (μ-pyridine-3,4-dicarboxylato-O,O′,O,O′)(aqua-O)calcium(II) contain molecular ribbons in which two adjacent calcium ions are bridged via oxygen atoms donated by the carboxylate group attached to carbon atom “3” in the pyridine ring. Both oxygen atoms are bidentate, each being coordinated to two caloium ions. In addition, every second pair of calcium(II) ions is bridged by a water oxygen atom. The coordination polyhedron around the calcium(II) ion is pentagonal bipyramidal; its equatorial plane is composed of two bridging oxygen atoms each belonging to the carboxylate group of the adjacent ligands, the bridging water oxygen atom and two coordinated water molecules. Another coordinated water oxygen atom constitutes the apex of the pyramid on one side of the pentagon, while two bridging carboxylate oxygen atoms donated by the same carboxylate group make two apices on the other side of the pentagon. The pyridine hetero-ring nitrogen atom does not participate in coordination to the central ion. Both oxygen atoms of the carboxylate group attached to the carbon atom in position “4” of the pyridine ring are not directly coordinated to the calcium(II) ion and act only as acceptors in the hydrogen bond system.     

The Crystal Structures of Two Calcium(II) Complexes with Pyrazine- 2,6-Dicarboxylate and Water Ligands

The structure of catena-{bis[(μ-aqua)(diaqua)(pyrazine-2,6-dicarboxylato-O,N-μ-O')](calcium(II)} consists of dimeric units composed of two calcium(II) ions, two ligand molecules and six water molecules. The calcium ions are bridged by two bidentate oxygen atoms, each donated by one carboxylic group of the ligand. The Ca(II) ion is also coordinated by one oxygen atom of the second carboxylate group and the hetero-ring nitrogen atom belonging to the same ligand molecule. Both calcium ions in a dimer are bridged to the Ca(II) ions in adjacent dimers by a pair of water molecules forming infinite molecular ribbons. In addition, each Ca(II) ion is coordinated by three water molecules; one of them is used for bridging the adjacent dimer. The coordination polyhedron around the Ca(II) ion is a pentagonal bipyramid with two apices above and one apex below the equatorial plane. The same molecular pattern is observed in the structure of catena-{bis[(μ-aqua)(diaqua)(pyrazine-2,6-dicarboxylato-O,N-μ-O')](calcium(II)} dihydrate which, in addition, contains two solvation water molecules per unit cell. In both compounds the molecular ribbons are held together by extended systems of hydrogen bonds.     

A one‐dimensional CdII coordination polymer constructed from 4‐(dimethylamino)pyridinium‐1‐acetate ligands and thiocyanate coordination bridges

A new cadmium–thiocyanate complex, namely catena‐poly[1‐carboxymethyl‐4‐(dimethylamino)pyridinium [cadmium(II)‐tri‐μ‐thiocyanato‐κ⁴N:S;κ²S:N] [[[4‐(dimethylamino)pyridinium‐1‐acetate‐κ²O,O′]cadmium(II)]‐di‐μ‐thiocyanato‐κ²N:S;κ²S:N]], {(C₉H₁₃N₂O₂)[Cd(NCS)₃][Cd(NCS)₂(C₉H₁₂N₂O₂)]}_n, was synthesized by the reaction of 4‐(dimethylamino)pyridinium‐1‐acetate, cadmium nitrate tetrahydrate and potassium thiocyanide in aqueous solution. In the crystal structure, two types of Cd^II atoms are observed in distorted octahedral coordination environments. One type of Cd^II atom is coordinated by two O atoms from the carboxylate group of the 4‐(dimethylamino)pyridinium‐1‐acetate ligand and by two N atoms and two S atoms from four different thiocyanate ligands, while the second type of Cd^II atom is coordinated by three N atoms and three S atoms from six different thiocyanate ligands. Neighbouring Cd^II atoms are linked by thiocyanate bridges to form a one‐dimensional zigzag chain and a one‐dimensional coordination polymer. Hydrogen‐bond interactions are involved in the formation of the supramolecular network.     

A ternary complex of aqua(18‐crown‐6)bis(o‐nitrophenolato)barium(II), the triaqua(18‐crown‐6)(o‐nitrophenolato)barium(II) cation and the o‐nitrophenolate anion

In the title compound [systematic name: tri­aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)(2‐nitro­phenolato‐κO)­barium(II)–aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)‐ bis(2‐nitro­phenolato‐κ²O,O′)­barium(II)–2‐nitro­phenolate (1/1/1)], [Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)(H₂O)₃][Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)₂(H₂O)](C₆H₄NO₃), the two Ba^II atoms encapsulated by the 18‐crown‐6 rings have different coordinations. Although both Ba^II atoms are coordinated to the six O atoms of the crowns, in the neutral moiety, the Ba^II atom is coordinated to one terminal O atom from a water mol­ecule, two phenolate O atoms and two nitro‐group O atoms, while in the cationic moiety, the Ba^II atom is coordinated to three terminal O atoms from water mol­ecules and one phenolate O atom. Both the crowns are eclipsed and translated along the b direction. In the asymmetric unit, the three components are interconnected by four O—H?O interactions. The packing is stabilized by two intermolecular C—H?O interactions and by one O—H?O interaction.     

Hydrogen‐bonded two‐ and three‐dimensional polymeric structures in the ammonium salts of 3,5‐dinitrobenzoic acid, 4‐nitrobenzoic acid and 2,4‐dichlorobenzoic acid

The structures of ammonium 3,5‐dinitrobenzoate, NH₄⁺·C₇H₃N₂O₆⁻, (I), ammonium 4‐nitrobenzoate dihydrate, NH₄⁺·C₇H₄NO₄⁻·2H₂O, (II), and ammonium 2,4‐dichlorobenzoate hemihydrate, NH₄⁺·C₇H₃Cl₂O₂⁻·0.5H₂O, (III), have been determined and their hydrogen‐bonded structures are described. All three salts form hydrogen‐bonded polymeric structures, viz. three‐dimensional in (I) and two‐dimensional in (II) and (III). With (I), a primary cation–anion cyclic association is formed [graph set R₄³(10)] through N—H...O hydrogen bonds, involving a carboxylate group with both O atoms contributing to the hydrogen bonds (denoted O,O′‐carboxylate) on one side and a carboxylate group with one O atom involved in two hydrogen bonds (denoted O‐carboxylate) on the other. Structure extension involves N—H...O hydrogen bonds to both carboxylate and nitro O‐atom acceptors. With structure (II), the primary inter‐species interactions and structure extension into layers lying parallel to (001) are through conjoined cyclic hydrogen‐bonding motifs, viz.R₄³(10) (one cation, an O,O′‐carboxylate group and two water molecules) and centrosymmetric R₄²(8) (two cations and two water molecules). The structure of (III) also has conjoined R₄³(10) and centrosymmetric R₄²(8) motifs in the layered structure but these differ in that the first motif involves one cation, an O,O′‐carboxylate group, an O‐carboxylate group and one water molecule, and the second motif involves two cations and two O‐carboxylate groups. The layers lie parallel to (100). The structures of salt hydrates (II) and (III), displaying two‐dimensional layered arrays through conjoined hydrogen‐bonded nets, provide further illustration of a previously indicated trend among ammonium salts of carboxylic acids, but the anhydrous three‐dimensional structure of (I) is inconsistent with that trend.     

Diaquabis(quinoxaline‐2‐carboxylato‐κ2N1,O)copper(II)

In the title compound, [Cu(C₉H₅N₂O₂)₂(H₂O)₂], the Cu^II ion lies on an inversion centre and has an elongated centrosymmetric octahedral environment, equatorially trans‐coordinated by two N,O‐bidentate quinoxaline‐2‐carboxylate ligands and axially coordinated by two water O atoms. Symmetry‐related molecules are linked by strong O—H...O hydrogen bonds, involving the uncoordinated carboxyl O atom of the carboxylate group and the coordinated water molecules, to form a two‐dimensional network. Weak intermolecular C—H...N interactions also stabilize the crystal structure.     

X-ray studies of lanthanide(III) complexes with 4-hydroxy-3-methoxybenzoate anion

Polycrystalline complexes of lanthanide(III) with 4-hydroxy-3-methoxybenzoic acid were obtained as hydrated compounds of general formula Ln(C₈H₇O₄)₃?·?nH₂O. After slow recrystallization we obtained single crystals of complexes and determined their structures. Praseodymium(III) and neodymium(III) form isostructural dihydrated complexes [Ln(C₈H₇O₄)₃(H₂O)₂], which crystallize in the triclinic system, space group P 1. Sm(III), Eu(III), Gd(III), Ho(III) and Tb(III) compounds are hexahydrates and also crystallize in the triclinic system, space group P 1. Dihydrated compounds form polymeric chains with metal centres linked by oxygen atoms of bridging carboxylates. Each metal ion is coordinated by chelating carboxylic group and two water molecules. Complexes of the second isostructural group form dinuclear units [Ln₂(C₈H₇O₄)₆(H₂O)₄]?·?8H₂O. Lanthanide(III) ions are linked by oxygen atoms of two chelating–bridging carboxylate groups. In the dimeric structure each metal ion coordinates additionally two chelating carboxylic groups and two water molecules.     

Poly[[aqua(4,4′‐diazenediyldibenzoato‐κ4O,O′:O′′,O′′′)cadmium(II)]: a twofold interpenetrated three‐dimensional coordination polymer of PtS topology

In the title coordination compound, [Cd(C₁₄H₈N₂O₄)(H₂O)]_n, the Cd^II cation and the coordinated water molecule lie on a twofold axis, whereas the ligand lies on an inversion center. The Cd^II center is five‐coordinated in a distorted square‐pyramidal geometry by four carboxylate O atoms from four different 4,4′‐diazenediyldibenzoate (ddb) anions and one water O atom. The three‐dimensional frameworks thus formed by the bridging ddb anions interpenetrate to generate a three‐dimensional PtS‐type network. Additionally, the coordination water molecule and the carboxylate O atom form a hydrogen‐bonding interaction, stabilizing the three‐dimensional framework structure.     

Dimeric Molecules in the Crystals of a Calcium(II) Complex with Pyridine-2,6-Dicarboxylate and Water Ligands

The crystals of bis[ w -pyridine-2,6-dicarboxylato-O,N,O')]bis[trisaqua-calcium(II)] di(pyridine-2,6-dicarboxylic acid) contain dimeric molecules composed of two calcium(II) ions and two ligand molecules. Calcium ions are bridged by two bidentate oxygen atoms each donated by one carboxylic group of the ligand [Ca―N 2.467(2)Å], a monodentate oxygen atom of the second carboxylate group of the ligand [Ca―N 2.484(2)Å] and three oxygen atoms donated by the water molecules [mean Ca―O 2.388(2)Å]. The coordination polyhedron is a distorted pentagonal bipyramid. Acid molecules were found to be located in the space between dimers and involved in an extended network of hydrogen bonds.     

Structures of CoII and ZnII complexes of the proton‐transfer compound derived from pyrazine‐2,3‐dicarboxylic acid and piperazine

The reaction of the proton‐transfer compound piperazine‐1,4‐diium pyrazine‐2,3‐dicarboxylate 4.5‐hydrate, C₄H₁₂N₂²⁺·C₆H₂N₂O₄²⁻·4.5H₂O or (pipzH₂)(pyzdc)·4.5H₂O (pyzdcH₂ is pyrazine‐2,3‐dicarboxylic acid and pipz is piperazine), (I), with Zn(NO₃)₂·6H₂O and CoCl₂·6H₂O results in the formation of bis(piperazine‐1,4‐diium) bis(μ‐pyrazine‐2,3‐dicarboxylato)‐κ³N¹,O²:O³;κ³O³:N¹,O²‐bis[aqua(pyrazine‐2,3‐dicarboxylato‐κ²N¹,O²)zinc(II)] decahydrate, (C₄H₁₂N₂)₂[Zn₂(C₆H₂N₂O₄)₄(H₂O)₂]·10H₂O or (pipzH₂)₂[Zn(pyzdc)₂(H₂O)]₂·10H₂O, (II), and catena‐poly[piperazine‐1,4‐diium [cobalt(II)‐bis(μ‐pyrazine‐2,3‐dicarboxylato)‐κ³N¹,O²:O³;κ³O³:N¹,O²] hexahydrate], {(C₄H₁₂N₂)[Co(C₆H₂N₂O₄)₂]·6H₂O}_n or {(pipzH₂)[Co(pyzdc)₂]·6H₂O}_n, (III), respectively. In (I), pyzdcH₂ is doubly deprotonated on reaction with piperazine as a base. Compound (II) crystallizes as a dimer, whereas compound (III) exists as a one‐dimensional coordination polymer. In (II), two pyzdc²⁻ groups chelate to each of the two Zn^II atoms through a ring N atom and an O atom of the 2‐carboxylate group. In one ligand, the adjacent 3‐carboxylate group bridges to a neighbouring metal atom. A water molecule ligates in the sixth coordination site. The structure of (II) can be described as a commensurate superlattice due to an ordering in the hydrogen‐bonded network. In (III), no water is coordinated to the metal atom and the coordination sphere is comprised of two N,O‐chelates plus two bridging O atoms. A large number of hydrogen bonds are observed in all three compounds. These interactions, as well as π–π and C=O...π stacking interactions, play important structural roles.     

Synthesis and Structural Studies of 2-(hydroxyimino)-1-methylpropylideneamino-phenyliminobutan-2-one Oxime, Ligand and its Complexes with Cu(II) and Ni(II)

A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H₂Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H₂Phmdo were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H₂Phmdo were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu^(II) or Ni^(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The data support the proposed structure of H₂Phmdo and its complexes.     

A novel helical copper complex: catena‐poly[[[aquacopper(II)]‐μ‐N‐(3‐carboxy‐2‐oxidobenzylidene‐κO2)glycinato‐κ3N,O′:O′] monohydrate]

In the polymeric title compound, {[Cu(C₁₀H₇NO₅)(H₂O)]·H₂O}_n, the Cu atom adopts a square‐based pyramidal coordination involving a N,O,O′‐tridentate glycine dianionic ligand, a water O atom and an apical bridging carboxylate O atom from an adjacent ligand. The title compound also adopts a carboxylate‐bridged chain structure. The molecular chain propagates in a helical fashion along the b axis of the monoclinic unit cell. Neighbouring chains are linked together to form a three‐dimensional network via hydrogen‐bonding interactions between coordinated and uncoordinated water molecules and O atoms of the bridging carboxylate groups.