Diverse dimensionalities and structures in copper coordination polymers incorporating substituted aliphatic dicarboxylate ligands and 4,4′-bipyridine

Hydrothermal synthesis has afforded a series of divalent copper coordination polymers with substituted glutarate ligands and the rigid rod tether 4,4′-bipyridine (bpy): {[Cu(Hdmg)₂(bpy)]·H₂O}_n (1, dmg = 3,3-dimethylglutarate), {[Cu₂(dmg)(bpy)₂](ClO₄)]_n (2), [Cu₂(emg)₂(bpy)]_n (3, emg = 3-ethyl, 3-methylglutarate) and [Cu₂(cda)₂(bpy)]_n (4, cda = 1,1-cyclopentanediacetate). All materials were characterized by single-crystal X-ray diffraction. Compound 1 manifests μ₂-oxygen bridged [Cu₂(Hdmg)₄] “X”-patterns connected into a ribbon motif by bpy linkers. On the other hand, 2 possesses mixed-valence [Cu^ICu^IICu^IICu^I] tetrameric clusters bridged by dmg ligands and pillared into an 8-connected body-centered cubic (bcu) cationic lattice by bpy linkers. Compounds 3 and 4 are structurally very similar, displaying chain motifs with {Cu₂(CO₂)₄} paddlewheels connected by dicarboxylates, in turn conjoined into (4,4)-grid coordination polymer layers by bpy tethers. Variable temperature magnetic data indicate the presence of very strong antiferromagnetic coupling within the {Cu₂(CO₂)₄} paddlewheels in the latter two complexes, with g = 2.30(2) and J = −352(3) cm⁻¹ for 3 and g = 2.35(2) and J = −352(5) cm⁻¹ for 4. Significant structural contrasts are evident when compared to previously reported divalent copper/4,4′-bipyridine coordination polymers with unsubstituted or 2-methyl substituted glutarate ligands.     

Synthesis, crystal structure and magnetic properties of a chain coordination polymer {[Cu4L2(H2O)] · H2O}n

A chain coordination polymer with the chemical formula {[Cu₄L₂(H₂O)] · H₂O}_n, has been synthesized by the assembly reaction of K₂CuL · 1.5H₂O and Cu(OAC)₂ · H₂O with a 1:1 mole ratio in methanol, where H₄L = 2-hydroxy-3-[(E)-({2-[(2-hydroxybenzoyl)imino]ethyl}imino)methyl] benzoic acid, OAC⁻ = CH₃COO⁻. The crystal structure was determined by single-crystal X-ray diffraction analysis, the compound has chain molecular structure formed by dissymmetrical tetranuclear units. The magnetic measurements showed that Cu-Cu of the complex exhibit antiferromagnetic interactions, and satisfactory fittings to the observed magnetic susceptibility data were obtained by assuming a binuclear system, and further using molecular field approximation to deal with magnetic exchange interactions between binuclear systems.     

Topological diversity in copper aromatic meta-dicarboxylate coordination polymers with bis(pyridylformyl)piperazine coligands

Hydrothermal synthesis has afforded divalent copper coordination polymers containing bis(4-pyridylformyl)piperazine (4-bpfp) tethers and aromatic meta-dicarboxylate ligands. {[Cu(ip)(4-bpfp)]·2H₂O}_n (1, ip = isophthalate) possesses a (4, 4) rectangular grid structure with an unusual ABCD stacking pattern along a 4₁ screw axis. Sterically bulky substituents in the 5-position of the isophthalate ligands reduced the coordination polymer dimensionality, with [Cu₂(tBuip)₂(4-bpfp)(H₂O)₂]_n (2, tBuip = 5-tert-butylisophthalate) and {[Cu(MeOip)(HMeOip)₂(4-bpfp)]·3H₂O}_n (3, MeOip = 5-methoxyisophthalate) displaying 1D polymeric ladder and chain motifs, respectively. Compound 3 possesses a rare twofold interpenetrated binodal supramolecular hms net with (6³)(6⁹8) topology. Longer meta-disposed acetate pendant arms induced a doubly interpenetrated 3D primitive cubic topology in {[Cu₂(1,3-phda)₂(H₂O)₂(4-bpfp)]}_n (4, 1,3-phda = 1,3-phenylenediacetate), which possesses antiferromagnetically coupled {Cu₂O₂} kernels (J = −6.14(8) cm⁻¹).     

Synthesis, crystal structures and magnetic behavior of two 3D coordination polymers using N-(4/3-carboxyphenyl)iminodiacetic acids as bridging ligands

Research on structure and magnetic properties of polynuclear metal complexes to understand the structural and chemical factors governing the electronic exchange coupling mediated by multi-atom bridging ligands is of growing interest. Hydrothermal treatment of Ni(NO₃)₂·6H₂O with N-(4-carboxyphenyl)iminodiacetic acid [N-4(H₃CPIDA)] at 150 °C yielded a 3D coordination polymer of general formula [Ni₃{N-4(CPIDA)}₂(H₂O)₃]·6H₂O (1). An analogous network of general formula [Co₃{N-3(CPIDA)}₂(H₂O)₃]·3H₂O (2) was synthesized using N-(3-carboxyphenyl)iminodiacetic acid [N-3(H₃CPIDA)] in combination with Co(NO₃)₂·6H₂O under identical reaction condition. Both the complexes contain trinuclear secondary building unit, and crystallized in monoclinic system with space groups C2/c (1) and P2₁/c (2), respectively. Variable temperature magnetic characterization of these complexes in the temperature range of 2-300 K indicated the presence of overall ferromagnetic and antiferromagnetic behavior for 1 and 2, respectively. Density functional theory calculations (B3LYP functional) were performed for further insight on the trinuclear units to provide a qualitative theoretical interpretation on the overall magnetic behavior of the complexes 1 and 2.     

Hydrothermal synthesis, structural determination, and thermal properties of 2-D cobalt- and nickel-based coordination polymers incorporating pendant-arm 3-pyridinecarboxylate ligands

Hydrothermal synthesis has afforded a family of four coordination polymers containing divalent nickel or cobalt and pendant-arm pyridylcarboxylate ligands. Utilizing 3-pyridylacetic acid and appropriate metal precursors produced [M(3-pyrac)₂(H₂O)₂] phases (M = Co (1); M = Ni (2)), while 3-pyridylpropionic acid generated [M(3-pyrprop)₂(H₂O)₂] coordination polymers (M = Co (3); M = Ni (4)). Single crystal X-ray diffraction revealed that 1-4 all display discrete 2-D layers with (4,4)-topology, anchored via bridging 3-pyridylcarboxylate ligands bearing monodentate carboxylate termini. Intralamellar hydrogen bonding between the aquo ligands and unligated carboxylate oxygen atoms is observed within 1-4. The pseudo 3-D structures of 1-4 are further assembled via stacking of individual neutral layers by interlayer hydrogen bonding. Thermal properties are also discussed.     

Syntheses, structures, and properties of novel one dimensional copper cyanide coordination polymers

Three new one-dimensional copper coordination polymers have been prepared and fully characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and magnetic susceptibility measurements. The structure of [Cu(CN)₂(bpy)] (1) (bpy = 2,2-bipyridyl) (monoclinic P2₁/c, a = 8.9761(7) Å, b = 16.731(1) Å, c = 8.0224(6) Å, β = 114.437(1)°) consists of Cu(II) metal centers coordinated by three cyanide ligands and chelated by one bpy to form the monomers Cu(CN)₃(bpy) with distorted square pyramidal geometry. Each monomer shares two cyanide ligands with two adjacent monomers to form infinite -Cu(II)-CN-Cu(II)-CN-Cu zigzag chains along the c-axis. The one-dimensional structure of [Cu(CN)(bpy)] (2) (hexagonal P3₂, a = 14.4883(6) Å, b = 12.921(1) Å) is built of tetrahedral Cu(CN)₂bpy metal complexes in which Cu(I) metal centers are coordinated by one nitrogen and one carbon from two different CN ligands, and two nitrogens from one bpy. The two CN ligands act as bridging ligands between adjacent monomers to form helical chains along the 3₂ screw axis. The crystal structure of [Cu₂Cl(CN)(bpy)] (3) (orthorhombic Pbca, a = 17.853(2) Å, b = 6.9724 (9) Å, c = 18.7357 (9) Å) consists of two monomers, CuCl₂(CN) and Cu(bpy)(CN) that share a cyanide ligand to form Cu₂Cl₂(CN)(bpy) dimers. The dimers link to each other by sharing Cl ligands leading to the formation of infinite Cu-Cl-Cu chain decorated by the complex Cu(CN)(bpy). Variable-temperature magnetic measurement shows an overall ferromagnetic behavior for compound 1. The magnetic pathway of compound 1 is through the cyanide bridge connecting apical and equatorial positions of adjacent copper (II) ions.     

Metal-dependent dimensionality in coordination polymers of a semi-rigid dicarboxylate ligand with additional amide groups: Syntheses, structures and luminescent properties

Three new coordination polymers, [CdL(H₂O)₃·H₂O]_n (1), [MnL(H₂O)₂]_n (2) and [ZnL]_n (3) (L = 2,2′-[1,4-bis(-benzamido)]diacetate) have been hydrothermally synthesized. Complex 1 and complex 2 are 1-D infinite zigzag chain and 2-D rectangular grid networks, respectively, in which are further stabilized by hydrogen bonds, thus affording two 3-D supramolecular frameworks. Complex 3 exhibits a (4, 4)-connected PtS topology. Moreover, an unusual phenomenon has been observed that the dimension of these coordination polymers gradually increases with the decrease of coordination numbers of metal ions. In addition, complex 1 exhibits a strong blue luminescence in the solid state at room temperature and may be potential candidate for luminescent materials.     

One-dimensional Zn(II) oligo(phenyleneethynylene)dicarboxylate coordination polymers: Synthesis, crystal structures, thermal and photoluminescent properties

The rigid, π-conjugated dicarboxylic acid 1,4-bis-[2-(4-carboxyphenyl)ethynyl]-2,5-dihexylbenzene {HO₂C[PEP(hexyl)₂EP]CO₂H} has been used to synthesise the new crystalline coordination polymers {Zn(O₂C[PEP(hexyl)₂EP]CO₂)(DMF)₂} (1) and {Zn(O₂C[PEP(hexyl)₂EP]CO₂)(DEF)₂} (2) in N,N-dimethylformamide (DMF) and N,N-diethylformamide (DEF), respectively, under mild conditions. Single-crystal X-ray crystallography revealed that 1 and 2 are isostructural and consist of uncharged zigzag coordination chains in which [Zn(formamide)₂]²⁺ fragments are bridged by (O₂C[PEP(hexyl)₂EP]CO₂)²⁻ ligands. The zigzag chains possess different intra-chain Zn?Zn?Zn angles due to the different volumes of the coordinating formamide molecules and subtle differences in the hydrophobic inter-chain interactions. Upon heating 1 and 2 to 200 °C, removal of the coordinating formamide molecules occurs, yielding the formamide-free compounds 1-DMF and 2-DEF of composition {Zn(O₂C[PEP(hexyl)₂EP]CO₂)}. According to powder X-ray diffraction and FT-IR spectroscopy studies, these materials are not crystalline but still possess partial ordering of intact, yet modified coordination chains in a structural arrangement which appears to be related to the respective parent compounds. Compounds 1, 2, 1-DMF and 2-DEF exhibit blue photoluminescence. The emission maxima of 1-DMF and 2-DEF are red-shifted by ca. 25 nm with respect to λ_max of 1 and 2, respectively.     

Two cadmium-thiocyanate coordination polymers with organic cations: Synthesis, crystal structures and luminescent properties

Two new inorganic-organic hybrid polymers [ClBzQl]₂[Cd(SCN)_3.5Br_0.5]·0.25H₂O (1) and [ClBzMePy][Cd(SCN)₃] (2) (ClBzQl = 1-(4′-Cl-benzyl)quinolinium cation and ClBzMePy = 1-(4′-Cl-benzyl)-2-methylpyridinium cation) have been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Crystal structure analyses show that two polymers belong to the monoclinic space group P2/n (1) and P2₁/c (2) with a = 18.548(2) Å, b = 9.526(1) Å, c = 20.689(2) Å, β = 94.008(1)°, V = 3646.6(5) Å³ for 1, and a = 11.195(2) Å, b = 16.415(3) Å, c = 10.751(2) Å, β = 102.930(3)°, V = 1925.7(7) Å³ for 2. The Cd atom exhibits a distorted octahedral coordination geometry for 1 and 2. For 1, a pair of 1,1-μ-SCN⁻ anions and a pair of 1,3-μ-SCN⁻ anions are alternately bridge adjacent Cd centers to form infinite polymeric chains. For 2, adjacent Cd atoms are linked by three 1,3-μ-SCN⁻ anions to form infinite [Cd(SCN)₃⁻]_∞ polymeric chains. The luminescent properties of the two polymers in the solid state at room temperature were investigated.     

Synthesis, crystal structure, magnetic properties and EPR studies of Cu/Hg bimetallic thiocyanato-bridged coordination polymer

The new Cu/Hg bimetallic thiocyanato-bridged coordination polymer, [Cu(2-bzpy)Hg(SCN)₄]_n, has been synthesized and characterized by elemental analysis, magnetic measurements, EPR, and X-ray crystallography. X-ray diffraction analysis reveals that the title complex structure creates 3D network.     

One-dimensional nickel and cobalt phthalate coordination polymers incorporating the kinked dipodal organodiimine 4,4′-dipyridylamine: Hydrothermal synthesis, structural characterization and thermal properties

Hydrothermal synthesis has afforded a family of three structurally related metal phthalate (pht) 1-D coordination polymers incorporating the kinked dipodal organodiimine 4,4′-dipyridylamine (dpa), with a general formulation of [L₂M(dpa)₂M(H₂O)₄] · H₂O (L = pht, M = Co, 1, M = Ni, 2; L = 4-methylphthalate (4-mpht), M = Co, 3). Single crystal X-ray diffraction of 1 and 2 revealed the presence of one-dimensional (1-D) polymeric chains consisting of [M(H₂O)₄]²⁺ and [M(pht)₂]²⁻ subunits linked through dpa tethers. These chains in turn conjoin into pseudo 2-D layers and 3-D networks via extensive supramolecular hydrogen bonding pathways. An extremely similar structure is observed for 3 despite the presence of the bulkier methyl group substituent. 1-3 were further characterized via infrared spectroscopy and elemental and thermogravimetric analysis. 1-3 represent the first dicarboxylate coordination polymers incorporating dpa tethering ligands.     

Synthesis, crystal structure and luminescent properties of two cadmium thiocyanate coordination polymers with benzylpyridyl cations

Two luminescent Cd(II) complexes [RBzPy][Cd(SCN)₃] for R = Cl (1) and Br (2) have been synthesized and structurally characterized. The Cd atoms are all N3S3 hexa-coordinated with six bridging SCN⁻ and form infinite [Cd(SCN)₃]_∞ polymeric chains. The layer arrangement of the anionic chains was obtained using the larger halogenated benzylpyridyl cations. The luminescent properties of 1 and 2 in the solid state were investigated.     

Cation control of dimensionality in isothiocyanate coordination polymers constructed from conformationally flexible 3,3′-bipyridine tethers

Two isothiocyanate coordination polymers constructed from the conformationally flexible tethering ligand 3,3′-bipyridine (3,3′-bpy) and divalent metal cations have been prepared and characterized via single crystal X-ray diffraction, infrared spectroscopy and elemental analysis. [Co(NCS)₂(3,3′-bpy)₂] (1), wherein the isothiocyanate ligands are coordinated in a trans fashion, manifests stacked two-dimensional (2-D) rhomboid grid layered motifs. In contrast, [Ni(NCS)₂(3,3′-bpy)₂] (2) possesses a doubly interpenetrated adamantoid three-dimensional (3-D) network despite the presence of trans isothiocyanate ligands. Thus, a metal cation-based control of coordination polymer dimensionality has been revealed in this system, reflective of different donor dispositions allowed by the conformational flexibility of the exobidentate 3,3′-bpy ligand. The 3-D framework of 2 decomposes at a temperature ∼40 °C higher than the 2-D network of 1.     

Synthesis, crystal and band structures, and optical and magnetic properties of a 1D copper coordination polymer with chelidamic acid ligand

A 1D coordination polymer, {[Cu₃(C₇H₂NO₅)₂(H₂O)₇]·2(H₂O)}_n (1), has been synthesized and characterized by X-ray single-crystal diffraction. The crystal structure of 1 features that distorted square-pyramidal coordination polyhedra composed of Cu atoms and chelidamic acid ligands are interlinked into a 1D polymer, further linked by hydrogen bonds into a 3D network. The optical properties were investigated in terms of diffuse reflectance and fluorescent spectra, which exhibit strong luminescence. The electronic band structure along with the density of states (DOSs) calculated by the DFT method indicate that compound 1 pose an energy band gap of 1.89 eV and that the origin of the emission band may be mainly ascribed to metal-to-ligand charge transfer (MLCT) where the electrons are transferred from the Cu-3d to O-2p and C-2p states.     

Anion-directed supramolecular assembly of cobalt(II)-fluconazole coordination polymers: Structural diversity, fluorescent and magnetic properties

Six fluconazole-bridged cobalt(II) coordination polymers, namely [Co(HFlu)₂(H₂O)₂](ClO₄)₂ (1), [Co(HFlu)₂(H₂O)(AcO)](AcO)·2C₂H₅OH (2), [Co(HFlu)₂Cl₂]·2C₂H₅OH (3), [Co₃(Flu)₂(acac)₄]·C₂H₅OH (4), [Co(HFlu)₂(malo)(H₂O)]·3H₂O (5), and [Co(HFlu)₂(fum)(H₂O)₂]·H₂O (6) (HFlu = 2-(2′,4′-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol, AcOH = acetate acid, Hacac = acetylacetonate, H₂malo = malonate acid, H₂fum = fumaric acid), have been synthesized and structurally characterized, and the thermal, fluorescent and magnetic properties investigated. The crystal structures display the one-dimensional cationic double-bridged chain consisting of 20-membered macrocycles to be parallel in 1 and perpendicular in 2. The structure of 3 consists of two-dimensional neutral rhombic grid in bc plane with (4,4) topology and alternative P/M helices intersecting at the Co sites along b direction. Complex 4 shows one-dimensional polymeric chain, in which binuclear Co₂(Flu)₂(acac)₂ units act as bridging blocks to link Co(acac)₂ nodes through triazolyl nitrogen atoms. The structure of 5 shows dimeric 20-membered macrometallacyclic motif. Complex 6 shows HFlu-bridged one-dimensional chain, which is stabilized by hydrogen-bonding interactions to produce alternative hydrophobic and hydrophilic architecture. Complexes 1-3 and 5-6 exhibit the similar electronic absorption and fluorescent spectra as those of HFlu, while complex 4 shows a fluorescent quenching phenomenon. Fluorescence titration of HFlu suggests that the fluorescent intensities at the maximal emission decrease upon the addition of Co(acac)₂. The variable-temperature magnetic measurement of 4 reveals weak ferromagnetic interaction combined with the spin-orbit coupling effect in the 1-D Co(II) chain.     

Cobalt isothiocyanate coordination polymers constructed from isomeric bis(pyridylmethyl)piperazine ligands: Ribbon and chain motifs and a novel (3,4)-connected supramolecular layer

Slow diffusion conditions have afforded a pair of cobalt isothiocyanate coordination polymers incorporating the flexible and hydrogen-bonding capable organodiimines N,N′-bis(3-pyridylmethyl)piperazine (3-bpmp) and N,N′-bis(4-pyridylmethyl)piperazine (4-bpmp), which were characterized by single-crystal X-ray diffraction and spectral and elemental analysis. While both [Co(NCS)₂(3-bpmp)₂]_n (1) and {[Co(NCS)₂(H₂O)₂(4-bpmp)] · 2H₂O}_n (2) possess one-dimensional (1-D) coordination polymer units, the donor disposition within the organodiimine promotes significant structural disparities. Compound 1 displays a 1-D double-chain motif, where each cobalt ion is bridged by two exobidentate 3-bpmp ligands. In contrast, compound 2 manifests a single chain pattern, with only one tethering 4-bpmp ligand joining adjacent cobalt ions. Extensive hydrogen-bonding patterns within the structure of 2 results in an intriguing supramolecular 2-D (3,4)-connected layer with (4.6²)₂(4².6².8²) topology. Thermal properties of these materials are also discussed.     

Aromatic N-oxide bridged copper(II) coordination polymers: Synthesis, characterization and magnetic properties

The complexes [Cu₂(o-NO₂-C₆H₄COO)₄(PNO)₂] (1), [Cu₂(C₆H₅COO)₄(2,2′-BPNO)]_n (2), [Cu₂(C₆H₅COO)₄(4,4′-BPNO)]_n (3), [Cu(p-OH-C₆H₄COO)₂(4,4′-BPNO)₂·H₂O]_n (4), (where PNO = pyridine N-oxide, 2,2′-BPNO = 2,2′-bipyridyl-N,N′-dioxide, 4,4′-BPNO = 4,4′-bipyridyl-N,N′-dioxide) are prepared and characterized and their magnetic properties are studied as a function of temperature. Complex 1 is a discrete dinuclear complex while complexes 2-4 are polymeric of which 2 and 3 have paddle wheel repeating units. Magnetic susceptibility measurements from polycrystalline samples of 1-4 revealed strong antiferromagnetic interactions within the {Cu₂}⁴⁺ paddle wheel units and no discernible interactions between the units. The complex 5, [Cu(NicoNO)₂·2H₂O]_n·4nH₂O, in which the bridging ligand to the adjacent copper(II) ions is nicotinate N-oxide (NicoNO) the transmitted interaction is very weakly antiferromagnetic.     

Divalent metal 1,3-phenylenediacetate coordination polymers with rigid or flexible dipyridyl tethers: Chains, layers, and interpenetrated networks

Hydrothermal synthesis has afforded four divalent metal 1,3-phenylenediacetate (1,3-phda) coordination polymers containing different dipyridyl-type ligands. {[Cu(1,3-phda)(dpa)(H₂O)]·H₂O}_n (1, dpa = 4,4′-dipyridylamine) exhibits a simple 2-D (4,4) rhomboid grid structure. {[Co(1,3-phda)(bpy)]·1.5H₂O}_n (2, bpy = 4,4′-bipyridine) also possesses a (4,4) layer structure, but with syn-syn bridged {Co₂(OCO)₂} dimeric kernels serving as 4-connected nodes. {[Co(H₂O)₄(3-bpmpH₂)](1,3-phda)₂·8H₂O}_n (3, 3-bpmp = bis(3-pyridylmethyl)piperazine) manifests cationic 1-D [Co(H₂O)₄(3-bpmpH₂)]_n⁴ⁿ⁺ chains linked into higher dimensionality by unligated 1,3-phda anions and curled tetrameric water molecule units. {[Ni(1,3-phda)(4-bpmp)(H₂O)₂]·2H₂O}_n (4, 4-bpmp = bis(4-pyridylmethyl)piperazine) has an underlying twofold interpenetrated 6⁵8 (cds) 3-D network topology. Variable temperature magnetic susceptibility studies revealed the presence of weak antiferromagnetic coupling and zero-field splitting (J = −1.65(4) cm⁻¹ and D = 30.9(7) cm⁻¹ with g = 2.20(1)) within the {Co₂(OCO)₂} dimers in 2.     

Hydrothermal synthesis, crystal structures and photoluminescent properties of four cadmium(II) coordination polymers derived from diphenic acid and auxiliary ligands

Four novel metal coordination polymers, [Cd(dpa)(H₂O)]_n (1), [Cd(dpa)(2,2′-bipy)]_n (2), {[Cd₂(dpa)₂(4,4′-bipy)₃](4,4′-bipy)(H₂O)₂}_n (3) and [Cd(dpa)(bim)₂(H₂O)]}_n (4) (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, bim = benzimidazole), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that the 2,4′-diphenic acids acts as bridging ligands, exhibiting rich coordination modes to link metal ions: bis-monodentate, bidentate chelating, chelating/bridging, monoatomic bridging and monodentate modes. In addition, the luminescent properties for compound 1-4 are also investigated in this work.     

Organocyanide coordination chemistry: Syntheses, structural characterisations and magnetic properties of copper (II) complexes with a di-imine/pyridine ligand

The reactions between the copper (II) salts [CuXL]PF₆ (L: 2,6-[1-(2,6-diisopropylphenylimino)ethyl]pyridine) (X = Cl 1, X = Br 2) and LiTCNQ, in a DMF/water mixture, or Et₃NH(TCNQ)₂, in acetone, produced the new complexes [CuXL(TCNQ)] (X = Cl 3, X = Br 4). For both compounds, crystallographic studies have clearly evidenced the existence of dimeric complexes [{CuClL}(TCNQ)]₂ owing to π-π overlap between two adjacent TCNQ⁻ radical anions. Compound 1 reacted with Et₄N(C₁₀N₇) to afford the mononuclear derivative [CuClL(C₁₀N₇)] (5), while its reaction with K₂C₁₀N₆ produced the dinuclear complex [(CuClL)₂(C₁₀N₆)] (6). The crystal structures of complexes 5 and 6 have been determined by X-ray crystallography. Magnetic studies have revealed that compound 6 displays weak antiferromagnetic interactions between the two metal centres, conversely compounds 3 and 5 exhibit purely paramagnetic behaviours.