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.     

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.     

Polymorphism in 3‐acetyl‐4‐hydroxy‐2H‐chromen‐2‐one

A new polymorph (denoted polymorph II) of 3‐acetyl‐4‐hydroxy‐2H‐chromen‐2‐one, C₁₁H₈O₄, was obtained unexpectedly during an attempt to recrystallize the compound from salt–melted ice, and the structure is compared with that of the original polymorph (denoted polymorph I) [Lyssenko & Antipin (2001). Russ. Chem. Bull. 50 , 418–431]. Strong intramolecular O—H...O hydrogen bonds are observed equally in the two polymorphs [O...O = 2.4263 (13) Å in polymorph II and 2.442 (1) Å in polymorph I], with a slight delocalization of the hydroxy H atom towards the ketonic O atom in polymorph II [H...O = 1.32 (2) Å in polymorph II and 1.45 (3) Å in polymorph I]. In both crystal structures, the packing of the molecules is dominated and stabilized by weak intermolecular C—H...O hydrogen bonds. Additional π–π stacking interactions between the keto–enol hydrogen‐bonded rings stabilize polymorph I [the centres are separated by 3.28 (1) Å], while polymorph II is stabilized by interactions between α‐pyrone rings, which are parallel to one another and separated by 3.670 (5) Å.     

Bis(2‐chloro‐5‐methylpyridine‐κN)bis(nitrato‐κ2O,O′)copper(II)

In the molecule of the title compound, [Cu(NO₃)₂(C₆H₆ClN)₂], the Cu atom lies on an inversion centre and is six‐coordinated by two pyridine N atoms and four nitrate O atoms in trans positions. The nitrate acts as an unsymmetrical bidentate ligand. The coordination geometry is octahedral, with the Cu—N and the two Cu—O distances being 1.9939 (16), 2.0246 (16) and 2.4866 (19) Å, respectively. There are five types of C—H⋯O hydrogen bonds. Two of these generate two‐dimensional molecular networks in the direction of the a axis, and the others connect adjacent molecular networks.     

A three‐dimensional supramolecular network built with the zigzag chain complex bis(5‐carboxy‐1H‐imidazole‐4‐carboxyl­ato)copper(II)

In the title complex, poly[copper(II)‐di‐μ‐5‐carboxy‐1H‐imidazole‐4‐carboxyl­ato], [Cu(C₅H₃N₂O₄)₂]_n or [Cu(H₂Imda)₂]_n, each imidazole moiety is bonded to the Cu atom via O and N atoms to give a square‐planar coordination [Cu—O = 2.014 (2) and 2.016 (2) Å, and Cu—N = 1.982 (3) and 1.992 (2) Å]. The distorted square‐pyramidal geometry at the Cu atom results from coordination to an adjacent O atom [Cu—O = 2.305 (2) Å], which generates zigzag chains. There is a sixth, weaker, octahedral coordination to the Cu atom from an inversion‐related O atom [Cu—O = 3.090 (2) Å], which links the chains into sheets in the (100) plane. Imidazole moieties in the sheets are linked in the [100] direction by pairs of N—H⋯O and C—H⋯O hydrogen bonds, thus generating a three‐dimensional network.     

trans‐Bis(hinokitiolato)copper(II) trans‐bis(hinokitiolato)palladium(II) cocrystals with (5/1) and (3/2) formulations

trans‐Bis(3‐isopropyl‐7‐oxocyclohepta‐1,3,5‐trien‐1‐olato)copper(II) trans‐bis(3‐isopropyl‐7‐oxocyclohepta‐1,3,5‐trien‐1‐olato)palladium(II) as the (5/1) and (3/2) composites [Cu(C₁₀H₁₁O₂)₂]·0.2[Pd(C₁₀H₁₁O₂)₂] and [Cu(C₁₀H₁₁O₂)₂]·0.67[Pd(C₁₀H₁₁O₂)₂], respectively, where 3‐isopropyl‐7‐oxocyclohepta‐1,3,5‐trien‐1‐olate is the systematic name for the hinokitiolate anion (hino), are the first mixed‐metal cocrystalline products isolated from the M_x(hino)_y family of complexes. These cocrystals contain square‐planar trans‐Cu(hino)₂ and trans‐Pd(hino)₂ molecules possessing crystallographic inversion symmetry. The bulk formulation for these cocrystalline compounds is Cu_1−xPd_x(hino)₂, where x is 0.166 (4) for the (5/1) product and 0.399 (4) for the (3/2) product. This bulk formulation is simply a convenient average expression of the whole‐molecule substitutional disorder present in these compounds. The M—O bonds are in the range 1.9210 (11)–1.9453 (10) Å, the O—M—O bite angles are in the range 82.94 (4)–83.36 (4)°, and all of the hinokitiolate O atoms are involved in C—H...O hydrogen‐bonding interactions.     

Two‐dimensional square‐grid frameworks formed by self‐associating copper(II) complexes with 1‐(3‐pyridyl)‐ and 1‐(4‐pyridyl)‐substituted butane‐1,3‐diones

In bis­[1‐(3‐pyridyl)butane‐1,3‐dionato]copper(II) (the Cu atom occupies a centre of inversion), [Cu(C₉H₈NO₂)₂], (I), and bis­[1‐(4‐pyridyl)butane‐1,3‐dionato]copper(II) methanol solvate, [Cu(C₉H₈NO₂)₂]·CH₃OH, (II), the O,O′‐chelating diketonate ligands support square‐planar coordination of the metal ions [Cu—O = 1.948 (1)–1.965 (1) Å]. Weaker Cu⋯N inter­actions [2.405 (2)–2.499 (2) Å], at both axial sides, occur between symmetry‐related bis­(1‐pyridylbutane‐1,3‐dion­ato)copper(II) mol­ecules. This causes their self‐organization into two‐dimensional square‐grid frameworks, with uniform [6.48 Å for (I)] or alternating [4.72 and 6.66 Å for (II)] inter­layer separations. Guest methanol mol­ecules in (II) reside between the distal layers and form weak hydrogen bonds to coordinated O atoms [O⋯O = 3.018 (4) Å].     

Bis(glycinato‐κ2N,O)dinitrosylmolybdenum(0) and bis(2‐aminoethanethiolato‐κ2N,S)dinitrosylmolybdenum(0) acetonitrile monosolvate

The title compounds, [Mo(C₂H₄NO₂)₂(NO)₂], (I), and [Mo(C₂H₆NS)₂(NO)₂]·CH₃CN, (II), contain distorted octahedral complexes in which the monoanionic N,S‐ and N,O‐bidentate ligands coordinate the molybdenum centres in different modes. The anionic O atoms of the glycinate ligands in (I) are coordinated trans to the nitrosyl ligands and the amine N atoms are located trans to each other, whereas in (II) the anionic S atoms are coordinated trans to each other and the amine N atoms are located trans to the nitrosyl ligands. Each compound has a single complete complex in the asymmetric unit on a general position. Six N—H...O contacts with N...O distances of less than 3.2 Å are observed in (I) between the amine groups and the nitrosyl and carboxylate O atoms. In the 1:1 solvate (II), the acetonitrile molecule forms short N—H...N contacts (N...N < 3.2 Å) between the solvent N atoms and one of the amine H atoms. In addition, three weak intermolecular N—H...S interactions (N...S > 3.3 Å) contribute to the stabilization of the structure of (II).     

Diamminebis(2,4,6‐tribromophenolato‐O)copper(II)

The title compound, [Cu(C₆H₂Br₃O)₂(NH₃)₂], a monomeric centrosymmetric Cu^II complex, crystallizes in the monoclinic system. The CuO₂N₂ coordination sphere is trans planar, [Cu—O 1.943 (5) Å and Cu—N 1.977 (6) Å], with the fifth and sixth coordination sites occupied by Br atoms from the phenoxide ions [Cu—Br 3.129 (1) Å], resulting in an elongated distorted octahedral structure for the CuO₂N₂Br₂ coordination. Each of the NH₃ groups forms two hydrogen bonds with the Br and O atoms of the CuO₂N₂Br₂ moiety of a neighbouring mol­ecule. This arrangement constitutes a one‐dimensional chain along the x axis of the unit cell.     

5‐n‐Butylpyridine‐2‐carboxylate–copper(II) and –iron(III) complexes

In trans‐bis(5‐n‐butyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­bis­(methanol‐κO)copper(II), [Cu(C₁₀H₁₂NO₂)₂(CH₄O)₂], the Cu atom lies on a centre of symmetry and has a distorted octahedral coordination. The Cu—O(methanol) bond length in the axial direction is 2.596 (3) Å, which is much longer than the Cu—­O(carboxylate) and Cu—N distances in the equatorial plane [1.952 (2) and 1.977 (2) Å, respectively]. In mer‐tris(5‐n‐bu­tyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­iron(III), [Fe(C₁₀H₁₂NO₂)₃], the Fe atom also has a distorted octahedral geometry, with Fe—O and Fe—N bond‐length ranges of 1.949 (4)–1.970 (4) and 2.116 (5)–2.161 (5) Å, respectively. Both crystals are stabilized by stacking interactions of the 5‐n‐butyl­pyridine‐2‐carboxyl­ate ligand, although hydrogen bonds also contribute to the stabilization of the copper(II) complex.     

Bis(μ‐succinato‐O,O′:O′′,O′′′)bis[bis(2‐amino‐1,3‐benzothiazole‐N3)copper(II)]

In the title dimeric complex, [Cu₂(C₄H₄O₄)₂(C₇H₆N₂S)₄], which possesses a centre of symmetry, the Cu atoms are enclosed in a 14‐membered ring. They adopt a distorted square‐bipyramidal (4+2) coordination. The four closest donor atoms are two N atoms of 2‐amino­benzo­thiazole ligands and two O atoms of the succinate carboxylate groups. They form a square‐planar cis arrangement, with an average Cu—N distance of 2.003 (3) Å and Cu—O distances of 1.949 (3) and 1.965 (3) Å. Two longer Cu—O bonds of 2.709 (3) and 2.613 (3) Å involving the remaining O atoms of the carboxylate groups complete the sixfold coordination of the Cu atoms. The H atoms of each amino group of the 2‐amino­benzo­thiazole molecules form intra‐ and inter­molecular N—H?O hydrogen bonds. A nearly perpendicular inter­molecular C—H?Cg interaction (Cg is the centroid of the imidazole ring) is observed. The intramolecular Cu?Cu distance is 6.384 (2) Å.     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Assembling an isomer grid: the isomorphous 4‐, 3‐ and 2‐fluoro‐N′‐(4‐pyridyl)benzamides

The three title isomers, 4‐, (I), 3‐, (II), and 2‐fluoro‐N′‐(4‐pyridyl)benzamide, (III), all C₁₂H₉FN₂O, crystallize in the P2₁/c space group (No. 14) with similar unit‐cell parameters and are isomorphous and isostructural at the primary hydrogen‐bonding level. An intramolecular C—H...O=C interaction is present in all three isomers [C...O = 2.8681 (17)–2.884 (2) Å and C—H...O117–118°], with an additional N—H...F [N...F = 2.7544 (15) Å] interaction in (III). Intermolecular amide–pyridine N—H...N hydrogen bonds link molecules into one‐dimensional zigzag chains [graph set C(6)] along the [010] direction as the primary hydrogen bond [N...N = 3.022 (2), 3.049 (2) and 3.0213 (17) Å]. These are augmented in (I) by C—H...π(arene) and cyclic C—F...π(arene) contacts about inversion centres, in (II) by C—F...F—C interactions [C...F = 3.037 (2) Å] and weaker C—H...π(arene)/C—H...F contacts, and in (III) by C—H...π(arene) and C=O...O=C interactions, linking the alternating chains into two‐dimensional sheets. Typical amide N—H...O=C hydrogen bonds [as C(4) chains] are not present [N...O = 3.438 (2) Å in (I), 3.562 (2) Å in (II) and 3.7854 (16) Å in (III)]; the C=O group is effectively shielded and only participates in weaker interactions/contacts. This series is unusual as the three isomers are isomorphous (having similar unit‐cell parameters, packing and alignment), but they differ in their interactions and contacts at the secondary level.     

The dinuclear copper(II) complexes di‐μ‐chlorido‐bis{[N,N′‐bis(4‐chlorobenzyl)propane‐1,2‐diamine]chloridocopper(II)} and di‐μ‐chlorido‐bis{[N,N′‐bis(3,4‐methylenedioxybenzyl)propane‐1,2‐diamine]chloridocopper(II)}

The two title dinuclear copper(II) complexes, [Cu₂Cl₄(C₁₇H₂₀Cl₂N₂)₂], (I), and [Cu₂Cl₄(C₁₉H₂₂N₂O₄)₂], (II), have similar coordination environments. In each complex, the asymmetric unit consists of one half‐molecule and the two copper centres are bridged by a pair of Cl atoms, resulting in complexes with centrosymmetric structures containing Cu(μ‐Cl)₂Cu parallelogram cores; the Cu...Cu separations and Cu—Cl—Cu angles are 3.4285 (8) Å and 83.36 (3)°, respectively, for (I), and 3.565 (2) Å and 84.39 (7)° for (II). Each Cu atom is five‐coordinated and the coordination geometry around the Cu atom is best described as a distorted square‐pyramid with a τ value of 0.155 (3) for (I) and 0.092 (7) for (II). The apical Cu—Cl bond length is 2.852 (1) Å for (I) and 2.971 (2) Å for (II). The basal Cu—Cl and Cu—N average bonds lengths are 2.2673 (9) and 2.030 (2) Å, respectively, for (I), and 2.280 (2) and 2.038 (6) Å for (II). The molecules of (I) are linked by one C—H...Cl hydrogen bond into a complex [10] sheet. The molecules of (II) are linked by one C—H...Cl and one N—H...O hydrogen bond into a complex [100] sheet.     

3‐(4‐Cyano­phenyl)­pentane‐2,4‐dione and its copper(II) complex

The β‐diketone 3‐(4‐cyano­phenyl)­pentane‐2,4‐dione crystallizes as the enol tautomer 4‐(2‐hydroxy‐4‐oxopent‐2‐en‐3‐yl)­benzo­nitrile, C₁₂H₁₁NO₂, (I), with an intramolecular O—H⋯O hydrogen bond [O⋯O = 2.456 (2) Å]. Reaction of (I) with copper acetate monohydrate in the presence of triethyl­amine leads to the formation of the copper(II) complexbis­[3‐(4‐cyano­phenyl)­pentane‐2,4‐dionato‐κ²O,O]copper(II), [Cu(C₁₂H₁₀NO₂)₂], (II). In the structure of (II), the Cu atom is coordinated by four β‐diketonate O atoms in a slightly distorted square‐planar geometry, with Cu—O distances in the range 1.8946 (11)–1.9092 (11) Å. The nitrile moieties in (II) make it a candidate for reaction with other metal ions to produce supramolecular structures.     

4‐Iodo­anilinium 3‐nitro­phthalate(1–): tripartite sheets built from O—H...O and N—H...O hydrogen bonds

In the title compound, 4‐iodoanilinium 2‐carboxy‐6‐nitrobenzoate, C₆H₇IN⁺·C₈H₄NO₆⁻, the anions are linked by an O—H...O hydrogen bond [H...O = 1.78 Å, O...O = 2.614 (3) Å and O—H...O = 171°] into C(7) chains, and these chains are linked by two two‐centre N—H...O hydrogen bonds [H...O = 1.86 and 1.92 Å, N...O = 2.700 (3) and 2.786 (3) Å, and N—H...O = 153 and 158°] and one three‐centre N—H...(O)₂ hydrogen bond [H...O = 2.02 and 2.41 Å, N...O = 2.896 (3) and 2.789 (3) Å, N—H...O = 162 and 105°, and O...H...O = 92°], thus forming sheets con­taining R(6), R(8), R(13) and R(18) rings.     

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.     

Crystal structures of the pyrazinamide–p‐aminobenzoic acid (1/1) cocrystal and the transamidation reaction product 4‐(pyrazine‐2‐carboxamido)benzoic acid in the molten state

The synthesis of pharmaceutical cocrystals is a strategy to enhance the performance of active pharmaceutical ingredients (APIs) without affecting their therapeutic efficiency. The 1:1 pharmaceutical cocrystal of the antituberculosis drug pyrazinamide (PZA) and the cocrystal former p‐aminobenzoic acid (p‐ABA), C₇H₇NO₂·C₅H₅N₃O, (1), was synthesized successfully and characterized by relevant solid‐state characterization methods. The cocrystal crystallizes in the monoclinic space group P2₁/n containing one molecule of each component. Both molecules associate via intermolecular O—H...O and N—H...O hydrogen bonds [O...O = 2.6102 (15) Å and O—H...O = 168.3 (19)°; N...O = 2.9259 (18) Å and N—H...O = 167.7 (16)°] to generate a dimeric acid–amide synthon. Neighbouring dimers are linked centrosymmetrically through N—H...O interactions [N...O = 3.1201 (18) Å and N—H...O = 136.9 (14)°] to form a tetrameric assembly supplemented by C—H...N interactions [C...N = 3.5277 (19) Å and C—H...N = 147°]. Linking of these tetrameric assemblies through N—H...O [N...O = 3.3026 (19) Å and N—H...O = 143.1 (17)°], N—H...N [N...N = 3.221 (2) Å and N—H...N = 177.9 (17)°] and C—H...O [C...O = 3.5354 (18) Å and C—H...O = 152°] interactions creates the two‐dimensional packing. Recrystallization of the cocrystals from the molten state revealed the formation of 4‐(pyrazine‐2‐carboxamido)benzoic acid, C₁₂H₉N₃O₃, (2), through a transamidation reaction between PZA and p‐ABA. Carboxamide (2) crystallizes in the triclinic space group P with one molecule in the asymmetric unit. Molecules of (2) form a centrosymmetric dimeric homosynthon through an acid–acid O—H...O hydrogen bond [O...O = 2.666 (3) Å and O—H...O = 178 (4)°]. Neighbouring assemblies are connected centrosymmetrically via a C—H...N interaction [C...N = 3.365 (3) Å and C—H...N = 142°] engaging the pyrazine groups to generate a linear chain. Adjacent chains are connected loosely via C—H...O interactions [C...O = 3.212 (3) Å and C—H...O = 149°] to generate a two‐dimensional sheet structure. Closely associated two‐dimensional sheets in both compounds are stacked via aromatic π‐stacking interactions engaging the pyrazine and benzene rings to create a three‐dimensional multi‐stack structure.     

Intra‐ and intermolecular Se...X (X = Se,O) interactions in selenium‐containing heterocycles: 3‐benzoylimino‐5‐(morpholin‐4‐yl)‐1,2,4‐diselenazole

In the selenium‐containing heterocyclic title compound {systematic name: N‐[5‐(morpholin‐4‐yl)‐3H‐1,2,4‐diselenazol‐3‐ylidene]benzamide}, C₁₃H₁₃N₃O₂Se₂, the five‐membered 1,2,4‐diselenazole ring and the amide group form a planar unit, but the phenyl ring plane is twisted by 22.12 (19)° relative to this plane. The five consecutive N—C bond lengths are all of similar lengths [1.316 (6)–1.358 (6) Å], indicating substantial delocalization along these bonds. The Se...O distance of 2.302 (3) Å, combined with a longer than usual amide C=O bond of 2.252 (5) Å, suggest a significant interaction between the amide O atom and its adjacent Se atom. An analysis of related structures containing an Se—Se...X unit (X = Se, S, O) shows a strong correlation between the Se—Se bond length and the strength of the Se...X interaction. When X = O, the strength of the Se...O interaction also correlates with the carbonyl C=O bond length. Weak intermolecular Se...Se, Se...O, C—H...O, C—H...π and π–π interactions each serve to link the molecules into ribbons or chains, with the C—H...O motif being a double helix, while the combination of all interactions generates the overall three‐dimensional supramolecular framework.     

Copper(II) bromide and copper(II) acetate complexes of 4,4′‐(p‐phenylene)bipyridazine

4,4′‐(p‐Phenylene)bipyridazine, C₁₄H₁₀N₄, (I), and the coordination compounds catena‐poly[[dibromidocopper(II)]‐μ‐4,4′‐(p‐phenylene)bipyridazine‐κ²N²:N^2′], [CuBr₂(C₁₄H₁₀N₄)]_n, (II), and catena‐poly[[[tetrakis(μ‐acetato‐κ²O:O′)dicopper(II)]‐μ‐4,4′‐(p‐phenylene)bipyridazine‐κ²N¹:N^1′] chloroform disolvate], {[Cu₂(C₂H₃O₂)₄(C₁₄H₁₀N₄)]·2CHCl₃}_n, (III), contain a new extended bitopic ligand. The combination of the p‐phenylene spacer and the electron‐deficient pyridazine rings precludes C—H...π interactions between the lengthy aromatic molecules, which could be suited for the synthesis of open‐framework coordination polymers. In (I), the molecules are situated across a center of inversion and display a set of very weak intermolecular C—H...N hydrogen bonds [3.399 (3) and 3.608 (2) Å]. In (II) and (III), the ligand molecules are situated across a center of inversion and act as N²,N^2′‐bidentate [in (II)] and N¹,N^1′‐bidentate [in (III)] long‐distance bridges between the metal ions, leading to the formation of coordination chains [Cu—N = 2.005 (3) Å in (II) and 2.199 (2) Å in (III)]. In (II), the copper ion lies on a center of inversion and adopts CuN₂Br₄ (4+2)‐coordination involving two long axial Cu—Br bonds [3.2421 (4) Å]. In (III), the copper ion has a tetragonal pyramidal CuO₄N environment. The uncoordinated pyridazine N atom and two acetate O atoms provide a multiple acceptor site for accommodation of a chloroform solvent molecule by trifurcated hydrogen bonding [C—H...O(N) = 3.298 (5)–3.541 (4) Å].