μ‐2,2′,6,6′‐Tetramethyl‐4,4′‐bipyridine‐κ2N1:N1′‐bis[(diethylenetriamine‐κ3N,N′,N′′)palladium(II)] tetranitrate

The title compound, [Pd₂(C₄H₁₃N₃)₂(C₁₄H₁₆N₂)](NO₃)₄, comprises discrete tetracationic dumbbell‐type dinuclear complex molecules and noncoordinating nitrate anions. Two Pd(dien)²⁺ moieties (dien is diethylenetriamine) are joined by the rigid linear exo‐bidentate bridging 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine ligand to form the dinuclear complex, which lies across a centre of inversion in the space group P2₁/n, so that the rings in the 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine bridging ligand are parallel. In the crystal, the primary and secondary amino groups of the dien ligand act as hydrogen‐bond donors towards the nitrate anions to form a three‐dimensional hydrogen‐bond network.     

{μ‐N,N′‐Bis[2‐(dimethylamino)ethyl]oxamidato(2–)‐κ6N,N′,O′:N′′,N′′′,O}bis[(2,2′‐bipyridine‐κ2N,N′)copper(II)] bis(perchlorate)

In the crystal structure of the title complex, [Cu₂(C₁₀H₂₀N₄O₂)(C₁₀H₈N₂)₂](ClO₄)₂, the deprotonated dmaeoxd²⁻ ligand {H₂dmaeoxd is N,N′‐bis[2‐(dimethylamino)ethyl]oxamide} occupies an inversion centre at the mid‐point of the central C—C bond and is thus in a trans conformation. The two Cu^II atoms are located in slightly distorted square‐based pyramidal environments. The binuclear units interact with each other viaπ–π interactions to form a one‐dimensional chain extending in the c direction.     

catena‐Poly[bis[tetraaquacobalt(II)‐μ‐4,4′‐bipyridine‐κ2N:N′] benzene‐1,2,4,5‐tetracarboxylate(4−) dihydrate]

The title compound, [Co(C₁₀H₈N₂)(H₂O)₄]₂(C₁₀H₂O₈)·2H₂O, consists of two crystallographically independent Co^II atoms linked by 4,4′‐bi­pyridine ligands into one‐dimensional chains, which are further connected into a three‐dimensional framework linked by [C₆H₂(COO)₄]^4? anions and water mol­ecules, achieved through complex hydrogen bonding.     

Poly[diaquabis(μ‐4,4′‐bipyridine‐κ2N:N′)bis(ethane‐1,2‐diol)di‐μ‐sulfato‐dicopper(II)]

The title compound, [Cu₂(SO₄)₂(C₁₀H₈N₂)₂(C₂H₆O₂)₂(H₂O)₂]_n, contains two crystallographically unique Cu^II centres, each lying on a twofold axis and having a slightly distorted octahedral environment. One Cu^II centre is coordinated by two bridging 4,4′‐bipyridine (4,4′‐bipy) ligands, two sulfate anions and two aqua ligands. The second is surrounded by two 4,4′‐bipy N atoms and four O atoms, two from bridging sulfate anions and two from ethane‐1,2‐diol ligands. The sulfate anion bridges adjacent Cu^II centres, leading to the formation of linear ...Cu1–Cu2–Cu1–Cu2... chains. Adjacent chains are further bridged by 4,4′‐bipy ligands, which are also located on the twofold axis, resulting in a two‐dimensional layered polymer. In the crystal structure, extensive O—H...O hydrogen‐bonding interactions between water molecules, ethane‐1,2‐diol molecules and sulfate anions lead to the formation of a three‐dimensional supramolecular network structure.     

Dichloro(4,4′‐dinonyl‐2,2′‐bipyridine‐κ2N,N′)platinum(II)

The title compound, [PtCl₂(C₂₈H₄₄N₂)], is a new square‐planar Pt^II complex con­taining a bi­pyridine moiety with two long alkyl‐chain substituents. The complex forms a segregated packing structure made up of the alkyl‐chain layers and paired coordination sites.     

(1,3‐Dimethylimidazolidine‐2‐selone‐κSe)bis(1,10‐phenanthroline‐κ2N,N′)copper(II) bis(perchlorate) and bis(2,2′‐bipyridyl‐κ2N,N′)(imidazolidine‐2‐thione‐κS)copper(II) bis(perchlorate)

In the first title salt, [Cu(C₁₂H₈N₂)₂(C₅H₁₀N₂Se)](ClO₄)₂, the Cu^II centre occupies a distorted trigonal–bipyramidal environment defined by four N donors from two 1,10‐phenanthroline (phen) ligands and by the Se donor of a 1,3‐dimethylimidazolidine‐2‐selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu—N distances span the range 1.980 (10)–2.114 (11) Å and the Cu—Se distance is 2.491 (3) Å. Intermolecular π–π contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C₁₀H₈N₂)₂(C₃H₆N₂S)](ClO₄)₂, the Cu^II centre occupies a similar distorted trigonal–bipyramidal environment comprising four N donors from two 2,2′‐bipyridyl (bipy) ligands and an S donor from an imidazolidine‐2‐thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu—N distances span the range 1.984 (6)–2.069 (7) Å and the Cu—S distance is 2.366 (3) Å. Intermolecular π–π contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N—H...O hydrogen bonds linking the imidazolidine N—H hydrogen‐bond donors to perchlorate O‐atom acceptors.     

μ‐{N,N′‐Bis[2‐(dimethyl­amino)ethyl]oxamidato(2–)}‐1κ2O,O′:2κ4N,N′,N′′,N′′′‐bis­(4,4′‐dimethyl‐2,2′‐bipyridine‐1κ2N,N′)dinickel(II) bis­(perchlorate)

In the crystal structure of the title complex, [Ni₂(C₁₀H₂₀N₄O₂)(C₁₂H₁₂N₂)₂](ClO₄)₂ or [Ni(dmaeoxd)Ni(dmbp)₂](ClO₄)₂ {H₂dmaeoxd is N,N′‐bis­[2‐(dimethyl­amino)ethyl]oxamide and dmbp is 4,4′‐dimethyl‐2,2′‐bipyridine}, the deprotonated dmaeoxd²⁻ ligand is in a cis conformation and bridges two Ni^II atoms, one of which is located in a slightly distorted square‐planar environment, while the other is in an irregular octa­hedral environment. The cation is located on a twofold symmetry axis running through both Ni atoms. The dmaeoxd²⁻ ligands inter­act with each other via C—H⋯O hydrogen bonds and π–π inter­actions, which results in an extended chain along the c axis.     

Poly[diaqua(μ‐4,4′‐bipyridine‐κ2N:N′)bis(μ‐cyanido‐κ2C:N)bis(cyanido‐κC)nickel(II)copper(II)]: a metal–organic cyanide‐bridged framework

The structure of the title compound, [NiCu(CN)₄(C₁₀H₈N₂)(H₂O)₂]_n or [{Cu(H₂O)₂}(μ‐C₁₀H₈N₂)(μ‐CN)₂{Ni(CN)₂}]_n, was shown to be a metal–organic cyanide‐bridged framework, composed essentially of –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains (4,4′‐bpy is 4,4′‐bipyridine) linked by [Ni(CN)₄]²⁻ anions. Both metal atoms sit on special positions; the Cu^II atom occupies an inversion center, while the Ni^II atom of the cyanometallate sits on a twofold axis. The 4,4′‐bpy ligand is also situated about a center of symmetry, located at the center of the bridging C—C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains, which are mutually perpendicular and non‐intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)₄]²⁻ anions coordinate to successive Cu^II atoms, forming zigzag –Cu—N[triple‐bond]C—Ni—C[triple‐bond]N—Cu– chains. In this manner, a three‐dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II)–4,4′‐bipyridine framework complexes synthesized to date. The coordination environment of the Cu^II atom is completed by two water molecules. The framework is further strengthened by O—H...N hydrogen bonds involving the water molecules and the symmetry‐equivalent nonbridging cyanide N atoms.     

Tetraaqua(4,4′‐dimethyl‐2,2′‐bipyridine‐κ2N,N′)nickel(II) sulfate monohydrate: a simple molecule with an extremely complex hydrogen‐bonding scheme

The title ionic compound, [Ni(C₁₂H₁₂N₂)(H₂O)₄]SO₄·H₂O, is composed of an Ni^II cation coordinated by a chelating 4,4′‐dimethyl‐2,2′‐bipyridine ligand via its two N atoms [mean Ni—N = 2.056 (2) Å] and by four aqua ligands [mean Ni—O = 2.073 (9) Å], the net charge being balanced by an external sulfate anion. The whole structure is stabilized by a solvent water molecule. Even though the individual constituents are rather featureless, they generate an extremely complex supramolecular structure consisting of a central hydrogen‐bonded two‐dimensional hydrophilic nucleus made up of complex cations, sulfate anions and coordinated and solvent water molecules, with pendant hydrophobic 4,4′‐dimethyl‐2,2′‐bipyridine ligands which interact laterally with their neighbours viaπ–π interactions. The structure is compared with closely related analogues in the literature.     

(Aqua‐2κO)bis(2,2′‐bipyridine‐1κ2N,N′){μ‐N‐[3‐(dimethylamino)propyl]‐N′‐(2‐oxidophenyl)oxamidato(3−)‐1:2κ2O,O′:κ4O′′,N,N′,N′′}copper(II)nickel(II) perchlorate

The title complex, [CuNi(C₁₃H₁₆N₃O₃)(C₁₀H₈N₂)₂(H₂O)]ClO₄, has a cis‐oxamide‐bridged heterobinuclear cation, with a Cu...Ni separation of 5.3297 (6) Å, counterbalanced by a disordered perchlorate anion. The Cu^II and Ni^II cations are located in square‐pyramidal and octahedral coordination environments, respectively. The complex molecules are assembled into a three‐dimensional supramolecular structure through hydrogen bonds and π–π stacking interactions. The influence of the two types of metal cation on the supramolecular structure is discussed.     

Di‐μ‐hydroxido‐bis{[bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine‐κ3N′,N′′,N′′′]copper(II)} bis(perchlorate)

The title compund, [Cu₂(OH)₂(C₂₂H₂₅N₃)₂](ClO₄)₂, is a copper(II) dimer, with two [CuL]²⁺ units [L is bis(6‐methyl‐2‐pyridylmethyl)(2‐phenylethyl)amine] bridged by hydroxide groups to define the {[CuL](μ‐OH)₂[CuL]}²⁺ cation. Charge balance is provided by perchlorate counter‐anions. The cation has a crystallographic inversion centre halfway between the Cu^II ions, which are separated by 3.0161 (8) Å. The central core of the cation is an almost regular Cu₂O₂ parallelogram of sides 1.931 (2) and 1.935 (2) Å, with a Cu—O—Cu angle of 102.55 (11)°. The coordination geometry around each Cu^II centre can be best described as a square‐based pyramid, with three N atoms from L ligands and two hydroxide O atoms completing the coordination environment. Each cationic unit is hydrogen bonded to two perchlorate anions by means of hydroxide–perchlorate O—H...O interactions.     

catena‐Poly[[diiodo­zinc(II)]‐μ‐4,4′‐bipyridine‐κ2N:N′]

The title compound, [ZnI₂(bipy)]_n (bipy is 4,4′‐bipyridine, C₁₀H₈N₂), has been prepared by the hydro­thermal reaction of ZnI₂ and bipy at 433 K. Each Zn atom is coordinated by two N atoms from two different bipy ligands and by two I atoms in a distorted tetra­hedral geometry, with Zn—N distances ranging from 2.068 (7) to 2.101 (8) Å and Zn—I distances ranging from 2.5471 (13) to 2.5673 (13) Å. The mol­ecular structure features a zigzag polymeric chain. Face‐to‐face π–π stacking inter­actions between adjacent bipy ligands stabilize the structure.     

The double‐stranded ladder‐like structure of poly[[bis(μ2‐acetato‐κ2O:O′)bis(acetato‐κO)bis(μ‐4,4′‐bipyridine‐κ2N:N′)dicopper(II)] 4‐nitrophenol disolvate tetrahydrate]

The reaction of 4,4′‐bipyridine with copper acetate in the presence of 4‐nitrophenol led to the formation of the title compound, {[Cu(CH₃COO)₂(C₁₀H₈N₂)]·C₆H₅NO₃·2H₂O}_n. The complex forms a double‐stranded ladder‐like coordination polymer extending along the b axis. The double‐stranded polymers are separated by 4‐nitrophenol and water solvent molecules. The two Cu^II centres of the centrosymmetric Cu₂O₂ ladder rungs have square‐pyramidal coordination environments, which are formed by two acetate O atoms and two 4,4′‐bipyridine N atoms in the basal plane and another acetate O atom at the apex. The ladder‐like double strands are separated from each other by one unit‐cell length along the c axis, and are connected by the water and 4‐nitrophenol molecules through a series of O—H...O and C—H...O hydrogen‐bonding interactions and two unique intermolecular π–π interactions.     

(1H‐Pyrazole‐κN2)(2,2′:6′,2′′‐terpyridine‐κ3N,N′,N′′)platinum(II) bis(perchlorate) nitromethane monosolvate

The reaction between [PtCl(terpy)]·2H₂O (terpy is 2,2′:6′,2′′‐terpyridine) and pyrazole in the presence of two equivalents of AgClO₄ in nitromethane yields the title compound, [Pt(C₃H₄N₂)(C₁₅H₁₁N₃)](ClO₄)₂·CH₃NO₂, as a yellow crystalline solid. Single‐crystal X‐ray diffraction shows that the dicationic platinum(II) chelate is square planar with the terpyridine ligand occupying three sites and the pyrazole ligand occupying the fourth. The torsion angle subtended by the pyrazole ring relative to the terpyridine chelate is 62.4 (6)°. Density functional theory calculations at the LANL2DZ/PBE1PBE level of theory show that in vacuo the lowest‐energy conformation has the pyrazole ligand in an orientation perpendicular to the terpyridine ligand (i.e. 90°). Seemingly, the stability gained by the formation of hydrogen bonds between the pyrazole NH group and the perchlorate anion in the solid‐state structure is sufficient for the chelate to adopt a higher‐energy conformation.     

Triaqua(2,2′‐bipyridine‐κ2N,N′)(nitrato‐κO)manganese(II) nitrate

The crystal structure of the title compound, [Mn(NO₃)(C₁₀H₈N₂)(H₂O)₃]NO₃, contains a monomeric [Mn(NO₃)(bpy)(H₂O)₃]⁺ cation (bpy is 2,2′‐bi­pyridine) and a nitrate anion. The Mn^II ion is coordinated by one chelating bpy [Mn—N 2.241 (3) and 2.259 (3) Å], three water mol­ecules [Mn—O 2.120 (3)–2.188 (3) Å] and a nitrate ligand [Mn—O 2.228 (2) Å] in a distorted octahedral geometry. There are O?H—O hydrogen‐bonding interactions between the ligated water mol­ecules and the ligated and unligated nitrate anions, resulting in double columns of stacked cations and anions.     

catena‐Poly[bis[silver(I)‐μ2‐4,4′‐bipyridine‐κ2N:N′] naphthalene‐2,6‐dicarboxylate tetrahydrate]: self‐assembly of a supramolecular framework via coordination bonds and supramolecular interactions

The ultrasonic reaction of AgNO₃, 4,4′‐bipyridine (bipy) and naphthalene‐2,6‐dicarboxylic acid (H₂NDC) gives rise to the title compound, {[Ag₂(C₁₀H₈N₂)₂](C₁₂H₆O₄)·4H₂O}_n. The NDC dianion is located on an inversion centre. The Ag^I centre is coordinated in a linear manner by two N atoms from two bipy ligands. The crystal structure consists of one‐dimensional Ag^I–bipy cationic chains and two‐dimensional NDC–H₂O anionic sheets, constructed by coordination bonds and supramolecular interactions, respectively.     

Dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylate and bis(dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylato‐κ2N,N′)copper(I) tetrafluoroborate

The single‐crystal X‐ray structures of dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylate, C₁₄H₁₂N₂O₄, and the copper(I) coordination complex bis(dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylato‐κ²N,N′)copper(I) tetrafluoroborate, [Cu(C₁₄H₁₂N₂O₄)₂]BF₄, are reported. The uncoordinated ligand crystallizes across an inversion centre and adopts the anticipated anti pyridyl arrangement with coplanar pyridyl rings. In contrast, upon coordination of copper(I), the ligand adopts an arrangement of pyridyl donors facilitating chelating metal coordination and an increased inter‐pyridyl twisting within each ligand. The distortion of each ligand contrasts with comparable copper(I) complexes of unfunctionalized 2,2′‐bipyridine.     

π‐Stacking and hydrogen bonding in catena‐poly[[(4,4′‐bipyridine‐κN)­di­oxo­uranium(VI)]‐di‐μ‐hydroxo]

The title compound, [UO₂(OH)₂(C₁₀H₈N₂)]_n, was obtained under hydro­thermal conditions. The U atom is seven‐coordinated and its environment is penta­gonal bipyramidal, with the oxo atoms in axial positions, and one N atom and four hydroxide groups in the equatorial plane. The hydroxide ions are bridging, which results in the formation of infinite chains with the bipyridine mol­ecules alternately located on either side. Neighbouring chains inter­penetrate so that each bipyridine ligand is involved both in hydrogen bonds with two hydroxide ions and in π‐stacking with its two neighbours from the next chain.     

Synthesis,crystal structure and magnetic properties of (acetato‐κ2O,O′)bis(5,5′‐dimethyl‐2,2′‐bipyridine‐κ2N,N′)nickel(II) perchlorate monohydrate

The title hydrated ionic complex, [Ni(CH₃COO)(C₁₂H₁₂N₂)₂]ClO₄·H₂O or [Ni(ac)(5,5′‐dmbpy)₂]ClO₄·H₂O (where 5,5′‐dmbpy is 5,5′‐dimethyl‐2,2′‐bipyridine and ac is acetate), (1), was isolated as violet crystals from the aqueous ethanolic nickel acetate–5,5′‐dmbpy–KClO₄ system. Within the complex cation, the Ni^II atom is hexacoordinated by two chelating 5,5′‐dmbpy ligands and one chelating ac ligand. The mean Ni—N and Ni—O bond lengths are 2.0628 (17) and 2.1341 (15) Å, respectively. The water solvent molecule is disordered over two partially occupied positions and links two complex cations and two perchlorate anions into hydrogen‐bonded centrosymmetric dimers, which are further connected by π–π interactions. The magnetic properties of (1) at low temperatures are governed by the action of single‐ion anisotropy, D, which arises from the reduced local symmetry of the cis‐NiO₂N₄ chromophore. The fitting of the variable‐temperature magnetic data (2–300 K) gives g_iso = 2.134 and D/hc = 3.13 cm⁻¹.     

Bis(3‐amino­pyridine‐κN)(4,4′‐di­methyl‐2,2′‐bipyridine‐κ2N,N′)(per­chlorato‐κO)copper(II) per­chlorate

The title compound, [Cu(ClO₄)(C₅H₆N₂)₂(C₁₂H₁₂N₂)]ClO₄, was prepared by in situ partial ligand substitution between 3‐amino­pyridine and 4,4′‐dimethyl‐2,2′‐bipyridine at room temperature. The central copper(II) ion is five‐coordinated by one bidentate 4,4′‐dimethyl‐2,2′‐bipyridine mol­ecule, two monodentate pyridine‐coordinated 3‐amino­pyridine mol­ecules and one apical O atom from the perchlorate counter‐ion. Inter­molecular N—H⋯O and C—H⋯O hydrogen‐bonding inter­actions form a hydrogen‐bond‐sustained network.