trans‐Diaquabis(3‐hydroxybenzoato‐κO1)bis(nicotinamide‐κN1)copper(II)

The title compound, [Cu(C₇H₅O₃)₂(C₆H₆N₂O)₂(H₂O)₂], is a two‐dimensional hydrogen‐bonded supramolecular complex. The Cu^II ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two pyridine N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₂²(4), R₂²(8) and R₂²(15) rings which lead to one‐dimensional polymeric chains. An extensive two‐dimensional network of N—H...O and O—H...O hydrogen bonds and C—H...π interactions are responsible for crystal stabilization.     

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.     

trans‐Diaquabis(nicotinamide‐κN)bis(salicylato‐κO)cobalt(II)

The title compound, [Co(C₇H₅O₃)₂(C₆H₆N₂O)₂(H₂O)₂], forms a three‐dimensional hydrogen‐bonded supramolecular structure. The Co^II ion is in an octahedral coordination environment comprising two pyridyl N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₂²(8), R₂²(12) and R₂²(14) rings, which lead to two‐dimensional chains. An extensive three‐dimensional supramolecular network of C—H...O, N—H...O and O—H...O hydrogen bonds and C—H...π interactions is responsible for crystal structure stabilization. This study is an example of the construction of a supramolecular assembly based on hydrogen bonds in mixed‐ligand metal complexes.     

Diaquabis(4‐fluorobenzoato‐κO)bis(nicotinamide‐κN)cobalt(II)

The title compound, [Co(C₇H₄FO₂)₂(C₆H₆N₂O)₂(H₂O)₂], is a three‐dimensional hydrogen‐bonded supramolecular complex. The Co^II ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two pyridyl N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₃²(6), R₂²(12) and R₂²(16) rings, which lead to two‐dimensional chains. An extensive three‐dimensional network of C—H...F, N—H...O and O—H...O hydrogen bonds and π–π interactions are responsible for crystal stabilization.     

Bis(acesulfamato‐κ2N3,O4)bis­(2‐amino­pyrimidine‐κN1)copper(II)

In the crystal structure of the title compound, bis­(2‐amino­pyrimidine‐κN¹)bis­[6‐meth­yl‐1,2,3‐oxathia­zin‐4(3H)‐one 2,2‐dioxide(1−)‐κ²N³,O⁴]copper(II), [Cu(C₄H₄NO₄S)₂(C₄H₅N₃)₂], the first mixed‐ligand complex of acesulfame, the Cu^II centre resides on a centre of symmetry and has an octa­hedral geometry that is distorted both by the presence of four‐membered chelate rings and by the Jahn–Teller effect. The equatorial plane is formed by the N atoms of two amino­pyrimidine (ampym) ligands and by the weakly basic carbonyl O atoms of the acesulfamate ligands, while the more basic deprotonated N atoms of these ligands are in the elongated axial positions with a strong misdirected valence. The crystal is stabilized by pyrimidine ring stacking and by inter­molecular hydrogen bonding involving the NH₂ moiety of the ampym ligand and the carbon­yl O atom of the acesulfamate moiety.     

Bis(isoquinoline‐1‐carboxylato‐κ2O,N)(1,10‐phenanthroline‐κ2N,N′)zinc(II) dimethylformamide sesqui­solvate

The asymmetric unit of the title compound, [Zn(C₁₀H₆NO₂)₂(C₁₂H₈N₂)]·1.5C₃H₇NO, contains one monomeric zinc com­plex and 1.5 disordered di­methyl­form­amide solvate mol­ecules. The Zn atom is coordinated to one 1,10‐phenanthroline ligand and to two iso­quinoline­carboxyl­ate anions (IQC^?) via their N and O atoms. The complex exhibits a distorted octahedral geometry around the Zn^II atom, with the apical positions occupied by the O atoms of the IQC^? ligands. The Zn atom lies 0.049 (1) Å out of the basal plane. The crystal packing is characterized by several hydrogen bonds.     

Dibromo(pyridoxal semicarbazone‐κ3N1,O3,O3′)copper(II)

The title compound, di­bromo(3‐hydroxy‐5‐hydroxy­methyl‐2‐methyl‐4‐pyridine­carbox­aldehyde semicarbazone‐κ³N¹,O³,O^3′)copper(II), [CuBr₂(C₉H₁₂N₄O₃)], consists of discrete complex units with the tridentate pyridoxal semicarbazone ligand as a zwitterion in an almost planar configuration. The Cu^II ions are in a distorted square‐pyramidal coordination, with the equatorial Br atom at a distance of 2.4017 (6) Å and the apical Br atom at a distance of 2.6860 (6) Å.     

(Glycylglycinato‐κ3O,N,N′)(2‐methyl‐1H‐benzimidazole‐κN3)copper(II) trihydrate

In the title compound, [Cu(C₄H₆N₂O₃)(C₈H₈N₂)]·3H₂O, the Cu^II atom is coordinated in a square‐planar manner by one O atom and three N atoms from glycylglycinate and 2‐methyl­benzimidazole ligands. The ternary complexes assemble into one‐dimensional chains through C—H⋯π inter­actions and direct N—H⋯O hydrogen bonding, as well as into hydrogen‐bonded water helices with branches which also link the complex chains into a three‐dimensional supra­molecular structure.     

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.     

catena‐Poly­[[bis­(quinoxaline‐κN)cobalt(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5] and catena‐poly­[[bis(quinoxaline‐κN)copper(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5]

Two new complexes, [Co(C₂N₃)₂(C₈H₆N₂)₂], (I), and [Cu(C₂N₃)₂(C₈H₆N₂)₂], (II), are reported. They are essentially isomorphous. Complex (I) displays distorted octahedral geometry, with the Co atom coordinated by four dicyan­amide nitrile N atoms [Co—N = 2.098 (3) and 2.104 (3) Å] in the basal plane, along with two monodentate quinoxaline N atoms [Co—N = 2.257 (2) Å] in the apical positions. In complex (II), the Cu atom is surrounded by four dicyan­amide nitrile N atoms [Cu—N = 2.003 (3) and 2.005 (3) Å] in the equatorial plane and two monodentate quinoxaline N atoms [Cu—N = 2.479 (3) Å] in the axial sites, to form a distorted tetragonal–bipyramidal geometry. The metal atoms reside on twofold axes of rotation. Neighbouring metal atoms are connected via double dicyan­amide bridges to form one‐dimensional infinite chains. Adjacent chains are then linked by π–π stacking interactions of the quinoxaline mol­ecules, resulting in the formation of a three‐dimensional structure.     

(Nitrato‐κO)bis(pyridine‐2‐carboxamide‐κ2N1,O)mercury(II) nitrate

In the title compound, [Hg(NO₃)(C₆H₆N₂O)₂]NO₃, the Hg^II atom is five‐coordinate. The distorted square‐pyramidal mercury(II) coordination environment is achieved by two N,O‐bidentate picolinamide ligands, with one O‐monodentate nitrate ion in the apical position. A seven‐coordinate extended coordination environment is completed by two additional weak Hg...O interactions, one from the coordinated nitrate ion and one from the other nitrate ion, to give seven‐coordination. The molecules are linked into a two‐dimensional network by N—H...O hydrogen bonds.     

Iodo­(picolinato‐κ2N,O)(picolinic acid‐κ2N,O)mercury(II)

The title compound, [Hg(C₆H₄NO₂)I(C₆H₅NO₂)], has twofold symmetry along the Hg—I bond. The Hg^II ion coordinates one I atom [at 2.6045 (4) Å], two N and two O atoms [at 2.298 (3) and 2.481 (2) Å] from one picolinate ion, and one picolinic acid mol­ecule in a very irregular trigonal–bipyramidal coordination. The single hydr­oxy H atom required for chemical neutrality is both statistically (by crystal symmetry) and structurally disordered, and is involved in an inter­molecular O—H⋯O hydrogen bond [O⋯O = 2.455 (4) Å], connecting the mol­ecules into one‐dimensional infinite chains along the [101] direction.     

(2‐Aminopyrimidine‐κN1)aqua(pyridine‐2,6‐dicarboxylato‐κ3O2,N,O6)copper(II): X‐ray and DFT calculated structure

In the title compound, [Cu(C₇H₃N₂O₄)(C₄H₅N₂)(H₂O)], (I), pyridine‐2,6‐dicarboxylate (pydc²⁻), 2‐aminopyrimidine and aqua ligands coordinate the Cu^II centre through two N atoms, two carboxylate O atoms and one water O atom, respectively, to give a nominally distorted square‐pyramidal coordination geometry, a common arrangement for copper complexes containing the pydc²⁻ ligand. Because of the presence of Cu...X_bridged contacts (X = N or O) between adjacent molecules in the crystal structures of (I) and three analogous previously reported compounds, and the corresponding uncertainty about the effective coordination number of the Cu^II centre, density functional theory (DFT) calculations were used to elucidate the degree of covalency in these contacts. The calculated Wiberg and Mayer bond‐order indices reveal that the Cu...O contact can be considered as a coordination bond, whereas the amine group forming a Cu...N contact is not an effective participant in the coordination environment.     

(Acetato‐κO)aqua(1H‐imidazole‐κN3)(picolinato‐κ2N,O)copper(II) 0.87‐hydrate: a Z′> 1 structure

The crystal structure of the title compound, [Cu(C₆H₄NO₂)(C₂H₃O₂)(C₃H₄N₂)(H₂O)]·0.87H₂O, has a square‐pyramidal‐coordinated Cu^II centre (the imidazole is trans to the picolinate N atom, the acetate is trans to the picolinate –CO₂ group and the aqua ligand is in a Jahn–Teller‐elongated apical position) and has two symmetry‐independent molecules in the unit cell (Z′ = 2), which are connected through complementary imidazole–picolinate N—H...O hydrogen bonding. The two partially occupied solvent water molecules are each disordered over two positions. The disordered solvent water molecules, together with pseudosymmetry elements, support the notion that a crystal structure with multiple identical chemical formula units in the structural asymmetric unit (Z′ > 1) can represent a crystal `on the way', that is, a kinetic intermediate form which has not yet reached its thermodynamic minimum. Neighbouring molecules form π–π stacks between their imidazole and picolinate N‐heterocycles, with centroid–centroid distances in the range 3.582 (2)–3.764 (2) Å.     

Poly[[μ3‐2‐(carboxylatomethyl)benzoato‐κ3O1:O2:O2]bis(1H‐imidazole‐κN3)copper(II)]

In the title polymeric compound, [Cu(C₉H₆O₄)(C₃H₄N₂)₂]_n, the copper(II) cation occupies an N₂O₃ coordination sphere defined by two 1H‐imidazole (imid) ligands in trans positions and three carboxylate O atoms from three different 2‐(carboxylatomethyl)benzoate (hpt²⁻) dianions. The geometry is that of a square pyramid with one of the O atoms at the apex, bridging neighbouring metal centres into an [–ON₂CuO₂CuN₂O–] dinuclear unit. These units are in turn connected by hpt anions into a reticular mesh topologically characterized by two types of loops, viz. a four‐membered Cu₂O₂ diamond motif and a 32‐membered Cu₄O₈C₂₀ ring. The imid groups do not take part in the formation of the two‐dimensional structure, but take part in the N—H...O interactions. These arise only within individual planes, interplanar interactions being only of the van der Waals type.     

Bis(1,10‐phenanthroline‐κ2N,N′)(squarato‐κO)copper(II) trihydrate

The title mononuclear [Cu(sq)(phen)₂]·3H₂O complex [sq is squarate (C₄O₄) and phen is 1,10‐phenanthroline (C₁₂H₈N₂)] has been synthesized and the structure consists of a neutral mononuclear [Cu(sq)(phen)₂] unit and three solvate water mol­ecules. The Cu^II ion has distorted square‐pyramidal coordination geometry, comprised of one carboxyl­ate O atom from a monodentate squarate ligand and four N atoms from two chelating phen ligands. An extensive three‐dimensional network of OW—H⋯O/OW hydrogen bonds, face‐to‐face π–­π interactions between the 1,10‐phenanthroline aromatic rings and a weak π–ring interaction are responsible for crystal stabilization.     

Dibromido(dimethyl sulfoxide‐κO)(1,10‐phenanthroline‐κ2N,N′)copper(II)

The solvent effect on the molecular structures of copper(II) complexes produced from the reaction between CuBr₂ and 1,10‐phenanthroline is evident. The momomeric title compound, [CuBr₂(C₁₂H₈N₂)(C₂H₆OS)], which consists of discrete units, is produced from this reaction in dimethyl sulfoxide (DMSO), whereas a polymeric copper(II) compound is known to be produced from the same reaction in the poor coordinating solvent ethanol. The geometry around the copper(II) ion in the title compound is best described as trigonal–bipyramidal distorted square‐based pyramidal, with a τ value of 0.37. The two phenanthroline N atoms, the DMSO O atom and one of the Br atoms occupy the four basal positions, while the second Br atom occupies the axial position. The magnetic susceptibility data also indicate that the title compound is monomeric, but there is still a weak antiferromagnetic interaction between paramagnetic copper(II) centers via the intermolecular `Cu—Br...Br—Cu' contact pathway.