Bis(μ‐3‐nitrobenzene‐1,2‐dicarboxyl­ato)‐κ8O1,O2:O2,O3;O3,O2:O2,O1‐bis­[triaqua­(2‐carboxy‐3‐nitro­benzoato‐κ2O,O′)lanthanum(III)] dihydrate

The title compound, [La₂(C₈H₃NO₆)₂(C₈H₄NO₆)₂(H₂O)₆]·2H₂O, consists of dimeric units related by an inversion center. The two La^III atoms are linked by two bridging bidentate carboxyl­ate groups and two monodentate carboxyl­ate groups. Each La^III atom is nine‐coordinated by six O atoms from five different carboxyl­ate groups and three from water mol­ecules. Hydrogen bonds between the water mol­ecules and between the solvent water and a carboxyl­ate O atom are observed in the structure. In the crystal packing, there are slipped π–π stacking inter­actions between the parallel benzene rings. Both hydrogen‐bonding and π–π inter­actions combine to stabilize the three‐dimensional supra­molecular network.     

Di­aqua(2,2′‐bi­pyridine)­malonato­manganese(II)

In the crystal structure of the title compound, [Mn(C₃H₂O₄)(C₁₀H₈N₂)(H₂O)₂], the Mn^II atom demonstrates a distorted octahedral geometry, being coordinated by two N atoms of a 2,2′‐bi­pyridine ligand, two O atoms from the carboxyl­ate groups of the chelating malonate dianion and two O atoms of two cis water mol­ecules. The complex mol­ecules are linked to form a three‐dimensional supramolecular array by both hydrogen‐bonding interactions between coordinated water and the carboxyl­ate groups of neighboring mol­ecules and aromatic π–π‐stacking interactions of the bi­pyridine rings.     

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

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

A single‐strand helical coordination polymer: catena‐poly­[[[tri­aqua­nickel(II)]‐μ‐2,2′‐bi­pyridine‐3,3′‐di­carboxyl­ato‐κ3N,N′:O] monohydrate]

The asymmetric unit of the title compound, {[Ni(C₁₂H₆N₂O₄)(H₂O)₃]·H₂O}_n, is composed of a lattice water mol­ecule and a nickel(II) ion that is coordinated by three water mol­ecules and the two N atoms of a 2,2′‐bi­pyridine‐3,3′‐di­carboxyl­ate ligand. The twist of the 2,2′‐bi­pyridine‐3,3′‐di­carboxyl­ate unit and the coordination of one carboxyl­ate group to a symmetry‐related Ni^II atom generate a helical chain that runs along the b axis. Intrahelical hydrogen bonds participate in controlling the orientation of the helices, and both right‐handed and left‐handed helices are connected by interhelical hydrogen bonds into two‐dimensional sheets.     

catena‐Poly­[[di­aqua­(nicotinato‐κ2O,O′)­cadmium(II)]‐μ‐nicotinato‐κ3N:O,O′]

The title compound, [Cd(C₆H₄NO₂)₂(H₂O)₂]_n, forms a one‐dimensional chain structure based on a Cd atom with approximate pentagonal bipyramidal coordination geometry and two nicotinate ligands in different coordination modes. One acts as a tridentate ligand, chelating one Cd atom through the carboxyl­ate group while simultaneously binding to a second symmetry‐related Cd atom through the pyridine N atom; the other acts only as a bidentate ligand through its carboxyl­ate group. Hydro­gen bonds utilizing the coordinated water mol­ecules, uncoordinated nitro­gen and carboxyl­ate O atoms as acceptors link the chains.     

Tetrakis(2,2′‐bipyridine‐κ2N,N′)­tetrakis(μ‐salicyl­ato‐κ3O,O′:O′′)‐quadro‐tetrazinc(II) decahydrate

The title compound, [Zn₄(C₇H₄O₃)₄(C₁₀H₈N₂)₄]·10H₂O, crystallizes as a centrosymmetric tetranuclear cyclic complex containing four Zn^II atoms bridged by four carboxyl­ate groups from salicyl­ate ligands, with a syn–anti configuration. Each Zn^II atom has a distorted trigonal–bipyramidal coordination geometry, formed by two N atoms of a 2,2′‐bipyridine ligand and three O atoms from two salicyl­ate ligands. The complex is stabilized by intramolecular π–π interactions between pairs of bi­pyridine rings and a 16‐membered gear‐wheel‐shaped cyclic framework. The hydrogen‐bonding network is formed via the water mol­ecules.     

catena‐Poly­[[tetra­aqua­iron(II)]‐μ‐succinato‐κ2O:O′]

The title complex, {[Fe(C₄H₄O₄)(H₂O)₄]}_n, is an infinite poly­meric compound bridged by the succinate dianion. Two carboxyl­ate groups coordinate in a monodentate manner to the Fe^II atom, in a trans fashion, with an O—Fe—O bond angle of 175.72 (6)° and Fe—O distances of 2.0886 (14) and 2.1008 (15) Å. One of the uncoordinated carboxyl­ate O atom forms an intramolecular hydrogen bond with a coordinated water mol­ecule. Extensive hydrogen bonding between parallel poly­meric complex chains results in a three‐dimensional supramolecular structure.     

Diaqua­malonato(1,10‐phenanthro­line)­zinc(II)

In the crystal structure of the title complex, [Zn(C₃H₂O₄)(C₁₂H₈N₂)(H₂O)₂], the Zn^II atom displays a distorted octa­hedral geometry, being coordinated by two N atoms from the 1,10‐phenanthroline ligand, two O atoms from different carboxyl­ate groups of the chelating malonate dianion and two O atoms of cis water mol­ecules. The complex mol­ecules are linked to form a three‐dimensional supramolecular array by both hydrogen‐bonding inter­actions between coordinated water molecules and the uncoordinated carboxyl­ate O atoms of neighboring mol­ecules, and aromatic π–π stacking inter­actions between neighboring phenanthroline rings.     

Polymeric aqua­(nitrato‐κ2O,O′)(1,10‐phenanthroline‐κ2N,N′)(2,3‐pyrazine­di­carboxyl­ato‐κ2N,O)­europium(III) monohydrate

In polymeric {[Eu(pzdc)(NO₃)(phen)(H₂O)]·H₂O}_n [pzdc is 2,3‐pyrazine­di­carboxyl­ate (C₆H₂O₄) and phen is 1,10‐phenanthroline (C₁₂H₈N₂)], each europium(III) ion is coordinated by seven O atoms (from three pzdc anions, a nitrate anion and a water mol­ecule) and the two N atoms of the phen ligand, resulting in a nine‐coordinated europium(III) center with a distorted monocapped square‐antiprismatic coordination polyhedron. Four pzdc anions bridge four europium(III) ions, forming a parallelogram unit, the four vertices of which are occupied by the four pzdc anions. Moreover, each parallelogram unit links six other adjacent parallelogram units, forming a two‐dimensional network with disordered lattice water mol­ecules.     

Aqua­bis(2‐nitro­benzoato‐κO)(1,10‐phenanthroline‐κ2N,N′)­zinc(II)

The title compound, [Zn(C₇H₄NO₄)₂(C₁₂H₈N₂)(H₂O)], has been synthesized. X‐Ray analysis reveals that it is a neutral zinc(II) mononuclear carboxyl­ate complex based on mixed N‐ and O‐donor ligands. The Zn atom is five‐coordinate in a distorted trigonal–bipyramidal coordination environment involving two O atoms of two monodentate 2‐nitro­benzoate mol­ecules, two N atoms of a 1,10‐phenanthroline mol­ecule and one O atom of a water mol­ecule. The axial positions are occupied by a carboxyl­ate O atom from the 2‐nitro­benzoate ligand and an N atom from the 1,10‐phenanthroline ligand [N—Zn—O = 167.66 (9)°].     

trans‐Diaquabis(1H‐imidazole‐4,5‐di­carboxyl­ate‐κ2N3,O4)­manganese(II)

In the title compound, [Mn(C₅H₃N₂O₄)₂(H₂O)₂], the Mn^II atom lies on an inversion centre, is trans‐coordinated by two N,O‐bidentate 1H‐imidazole‐4,5‐di­carboxyl­ate monoanionic ligands [Mn—O = 2.202 (3) Å and Mn—N = 2.201 (4) Å] and two water mol­ecules [Mn—O = 2.197 (4) Å], and exhibits a distorted octahedral geometry, with adjacent cis angles of 76.45 (13), 86.09 (13) and 89.20 (13)°. The complete solid‐state structure can be described as a three‐dimensional supramol­ecular framework, stabilized by extensive hydrogen‐bonding interactions involving the coordinated water mol­ecules, the carboxy O atoms and the protonated imidazole N atoms of the imidazole‐4,5‐di­carboxyl­ate ligands.     

A one‐dimensional ladder‐like coordination polymer derived from chains formed via hydrogen bonds: catena‐poly­[[aqua­di­pyridine­nickel(II)]‐μ‐2,2′‐di­thio­dibenzoato‐κ3O,O′:O′′]

The title one‐dimensional chain nickel(II)–di­sulfide complex, [Ni(C₁₄H₈O₄S₂)(C₅H₅N)₂(H₂O)]_n, has each Ni^II cation coordinated by two N atoms from two pyridine ligands, three carboxyl­ate O atoms from two different di­thio­dibenzoate ligands and one O atom from a coordinated water mol­ecule, in a distorted octahedral coordination geometry. Each di­thio­dibenzoate ion links two Ni^II cations through its carboxyl­ate O atoms, making the structure polymeric. Hydro­gen‐bond interactions between two shoulder‐to‐shoulder chains lead to the formation of a ladder‐like structure.     

trans‐Di­aqua­bis(6‐hydroxy­picolinato‐κ2N,O2)copper(II)

In the title compound, [Cu(C₆H₄NO₃)₂(H₂O)₂], the Cu^II ion lies on an inversion centre and has an elongated octahedral environment, equatorially trans‐coordinated by two N,O‐bidentate picolinate ligands and axially coordinated by two water O atoms. The complex mol­ecules form layers, which are linked by O—H⋯O hydrogen bonds between the aqua ligands and neighbouring carboxyl­ate groups. An intramolecular hydrogen bond between the coordinated carboxyl­ate O atom and the hydroxy H atom is also observed.     

Poly[[μ‐aqua‐bis­(μ‐2,4‐dichloro­phen­oxy­acetato)barium(II)] monohydrate]

In the title coordination polymer, {[Ba(C₈H₅Cl₂O₃)₂(H₂O)]·H₂O}_n, each Ba^II atom is nine‐coordinated by six carboxyl­ate O atoms and one ether O atom from five symmetry‐related 2,4‐dichloro­phenoxy­acetate ligands, and by two O atoms from water mol­ecules, thus defining a distorted tricapped trigonal prism. The Ba^II ions are bridged by bidentate water mol­ecules and by tridentate and tetra­dentate 2,4‐dichloro­phenoxy­acetate groups, leading to a two‐dimensional layer structure. The crystal structure is further stabilized by hydrogen‐bonding inter­actions within each layer.     

Zwitterionic 4‐piperidine­carboxyl­ic acid monohydrate

The title compound, 4‐piperidinio­carboxyl­ate (isonipecotic acid), crystallizes as a zwitterion and incorporates one water mol­ecule, i.e. C₆H₁₁NO₂·H₂O. The piperidine ring adopts a chair conformation and the α‐carboxyl­ate group is oriented in the equatorial position. The combination of the interactions between the α‐amino and α‐carboxyl­ate groups and the water mol­ecules builds a three‐dimensional assembly of hydrogen bonds.     

Poly­[trans‐di­aqua­manganese(II)‐μ‐(3‐pyridine­carboxyl­ato‐N:O)‐μ‐(3‐pyri­dinecarboxyl­ato‐O:N)]

The title complex, [Mn^II(nic)₂(H₂O)₂]_n [nic is 3‐pyridine­carboxyl­ate (also called nicotinate), C₆H₄NO₂^?], has a two‐dimensional layer structure with the unique Mn atom on an inversion centre. In each layer, all nicotinate ligands are coordinated to Mn atoms in a bridging/bidentate mode, thus linking the {Mn^II(nic)₂(H₂O)₂} monomeric units together to form a dative‐bond‐based layered polymer. The intra‐layer hydrogen bonds involving all water mol­ecules and the carboxyl­ate groups may play an auxiliary part in stabilizing the layer. The layers are arranged in an ordered manner along the a axis through van der Waals forces so as to complete the solid‐state structure of the crystal.     

catena‐Poly[[bis[pentaaquaerbium(III)]‐μ‐benzenehexacarboxylato] tetrahydrate]

The title compound is composed of one‐dimensional polymeric {[Er₂(C₁₂O₁₂)(H₂O)₁₀]·4H₂O}_n chains containing Er in a slightly distorted antiprismatic eightfold coordination. The benzene­hexa­carboxyl­ate ion is located about an inversion centre. Water mol­ecules of crystallization, linked by hydrogen bonding to water mol­ecules of the rare earth coordination spheres or the carboxyl­ate groups of the organic ligands, fill the space generated by the packing of the separated chains.     

catena‐Poly[[copper(II)‐μ‐2‐[bis­(2‐pyridylmeth­yl)amino]butyrato‐κ4N,N′,N′′,O:κO′] perchlorate]

The copper(II) ion in the syn–anti carboxyl­ate‐bridged one‐dimensional zigzag chain title complex, {[Cu(C₁₆H₁₈N₃O₂)]ClO₄}_n, exhibits a distorted trigonal–bipyramidal environment. Two N atoms and one carboxyl­ate O atom of the ligand form the basal plane, while the axial positions are filled by an N atom of the ligand and one O atom belonging to the carboxyl­ate group of an adjacent mol­ecule. The crystal packing is enhanced by C—H⋯O(perchlorate) hydrogen bonds.     

Poly­[[di­aqua­cobalt(II)]‐μ‐4,4′‐bi­pyridine‐κ2N:N′‐μ‐p‐phenyl­enebis­(oxy­acetato)‐κ2O:O′]

The title compound, [Co^II(C₁₀H₈O₆)(C₁₀H₈N₂)(H₂O)₂]_n, was obtained by the hydro­thermal reaction of CoSO₄ with benzene‐1,4‐dioxy­di­acetate [systematic name: p‐phenyl­ene­bis­(oxy­acetate)] and 4,4′‐bi­pyridine (4,4′‐bpy). The Co atom lies at an inversion center and the benzene‐1,4‐dioxydiacetate and 4,4′‐bipyridine moieties lie about other inversion centers. The benzene‐1,4‐dioxydiacetate ligands bridge the octahedral Co^II coordination centers, forming a one‐dimensional zigzag chain. The chains are further bridged by 4,4′‐bpy ligands, forming a novel two‐dimensional supramolecular architecture. Hydro­gen‐bonding interactions between the coordinated water mol­ecules and the carboxyl­ate O atoms lead to the formation of a three‐dimensional network structure.     

2‐Amino‐5‐chloro‐1,3‐benzoxazol‐3‐ium 2‐(3,4‐di­chloro­phenoxy)­acetate

The 1:1 organic salt of the title compound, C₇H₆ClN₂O⁺·C₈H₅Cl₂O₃^? or [(2‐ABOX)(3,4‐D)], comprises the two constituent mol­ecules associated by an R₂²(8) graph‐set interaction through the carboxyl­ate group of 3,4‐D across the protonated N/N sites of 2‐ABOX [N?O 2.546 (3) and 2.795 (3) Å]. Cation/anion pairs associate across an inversion centre forming discrete tetramers via an additional three‐centre hydrogen‐bonding association from the latter N amino proton to a phenoxy O atom [N?O 3.176 (3) Å] and a carboxyl­ate O atom [N?O 2.841 (3) Å]. This formation differs from the polymeric hydrogen‐bonded chains previously observed for adduct structures of 2‐ABOX with carboxyl­ic acids.