Studies on copper(II) complexes of some polyaza macrocycles derived from 1,2-diaminoethane

Syntheses of copper(II) complexes of 20-membered and 15-membered aza macrocycles 1,3,6,8,11,13,16,18-octaaza-2,7,12,17-tetrachlorocycloeicosane (OTCE, [20]-N₈) and 1,3,6,8, 11,13-hexaazacyclopentadecane (HCPD, [15]-N₆) involving metal template condensation between 1,2-diaminoethane, trichloromethane and dichloromethane, respectively, are reported. Formulation of [Cu₄(OTCE)(H₂O)₈]Cl₈ and [Cu₃(HCPD)(H₂O)₆]Cl₆ · 2H₂O and the ligand hydrochlorides OTCE · 8HCl and HCPD · 6HCl are supported by elemental analyses, conductivity measurements, and spectral studies. For a comparative cavity size effect on the stability constant, potentiometric measurements on the copper complexes of the generated macrocycles [15]-N₆ and [20]-N₈ and the structurally related larger macrocycle 1,3,6,8,11,13,16,18,21,23-decaaza-2,2,7,7,12,12,17,17,22,22-decachlorocyclopentacosane (DDCP, [25]-N₁₀, prepared recently) have been performed in aqueous solution at 25°C (μ = 0.1 M KNO₃). Very high stability constants obtained for reaction Cu²⁺ + A ? CuA²⁺ (A = ligand, log K = 20.51 and 25.87, respectively, for OTCE and DDCP systems) are a reflection on the folding of the ligand to provide a small cavity suitable for fitting of the copper ion. Further, a high equilibrium constant value for CuA²⁺ + Cu²⁺ ? Cu₂A⁴⁺ (OTCE system, log K = 14.59) or Cu₂A⁴⁺ + Cu²⁺ ? Cu₃A⁶⁺ (DDCP system, log K = 16.69) is due to suitable fitting of two and three copper ions in the 20-membered and 25-membered ring cavity of OTCE and DDCP, respectively.     

Molecular modeling,spectral, and biological studies of 4-formylpyridine-4 N-(2-pyridyl) thiosemicarbazone (HFPTS) and its Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Cd(II), Hg(II), and UO2(II) complexes

The present work describes the preparation and characterization of some metal ion complexes derived from 4-formylpyridine-⁴ N-(2-pyridyl)thiosemicarbazone (HFPTS). The complexes have the formula; [Cd(HFPTS)₂H₂O]Cl₂, [CoCl₂(HPTS)]·H₂O, [Cu₂Cl₄(HPTS)]·H₂O, [Fe (HPTS)₂Cl₂]Cl·3H₂O, [Hg(HPTS)Cl₂]·4H₂O, [Mn(HPTS)Cl₂]·5H₂O, [Ni(HPTS)Cl₂]·2H₂O, [UO₂(FPTS)₂(H₂O)]·3H₂O. The complexes were characterized by elemental analysis, spectral (IR, ¹H-NMR and UV–Vis), thermal and magnetic moment measurements. The neutral bidentate coordination mode is major for the most investigated complexes. A mononegative bidentate for UO₂(II), and neutral tridentate for Cu(II). The tetrahedral arrangement is proposed for most investigated complexes. The biological investigation displays the toxic activity of Hg(II) and UO₂(II) complexes, whereas the ligand displays the lowest inhibition activity toward the most investigated microorganisms.     

Oxidative DNA cleavage by Cu(II) complexes of 1,10-phenanthroline-5,6-dione

A dimeric dichloro-bridged copper(II) complex [Cu₂(pdon)₂Cl₄] · 2DMF (1) and two mononuclear copper(II) complexes [Cu(pdon)(DMSO)Cl₂] · DMSO · H₂O (2) and [Cu(pdon)₃] · (ClO₄)₂ · 2.25CH₃CN · 6H₂O (3) (pdon = 1,10-phenanthroline-5,6-dione) have been synthesized and characterized. Variable-temperature magnetic susceptibility studies indicate the existence of weak anti-ferromagnetic coupling in the binuclear complex. The interaction of these complexes with CT-DNA (calf thymus DNA) has been studied using absorption and emission spectral methods. The apparent binding constants (K _app) for 1, 2 and 3 are 5.20 × 10⁵, 2.68 × 10⁵ and 7.05 × 10⁵ M^?1, respectively, showing moderate intercalative binding modes. All of these complexes cleave plasmid DNA to nicked DNA in a sequential manner as the concentration or reaction time is increased. The cleavage mechanism between the complex and plasmid DNA is likely to involve singlet oxygen ¹O₂ and ?OH as reactive oxygen species.     

Supramolecular networks constructed by cationic copper(II) complexes incorporating hybrid water–anionic polymeric assemblies

Two complexes, [Cu₂(TFSA)(2,2′-bpy)₄]?·?TFSA?·?8H₂O (1) and {[Cu(4,4′-bpy)(H₂O)₂]?·?TFSA?·?6H₂O} _n (2) (H₂TFSA?=?tetrafluorosuccinic acid, 2,2′-bpy?=?2,2′-bipyridine, and 4,4′-bpy?=?4,4′-bipyridine), have been synthesized and structurally characterized by X-ray structural analyses. Complex 1 is a binuclear molecule bridged by TFSA ligands; 2 is a 1-D chain bridged by 4,4′-bpy ligands. The asymmetric units of the two complexes are composed of cationic complexes [Cu₂(TFSA)(2,2′-bpy)₄]²⁺ (1) and [Cu(4,4′-bpy)(H₂O)₂]²⁺ (2), free TFSA anion, and independent crystallization water molecules. A unique 2-D hybrid water–TFSA anionic layer by linkage of {[(H₂O)₈(TFSA)]^2?} _n fragments consisting of 1-D T6(0)A2 water tape and TFSA anionic units by hydrogen bonds in 1 was observed. Unique 2-D hybrid water–TFSA anionic layer generated by the linkage of {[(H₂O)₆(TFSA)]^2?} _n fragments consisting of cyclic water tetramers with appended water molecules and TFSA anionic units, and 1-D metal–water tape [Cu–H₂O?···?(H₂O)₆?···?H₂O^?] _n in 2 were found. 3-D supramolecular networks of the two complexes consist of cationic complexes and water–TFSA anionic assemblies connected by hydrogen bonds.     

Structural aspect of the interaction of copper(I) chloride with propargyl alcohol in aqueous anilinium chloride

Crystals of the formula (An)₃[Cu₄Cl₇] (I) and (An)₃[Cu₈Cl₁₀(C? CCH₂OH)]· 2H₂O (II) were obtained in the system AnCl-CuCl-H₂O-HC? CCH₂OH [An is the anilinium cation (C₆H₅NH ₃ ⁺ )] and studied by X-ray diffraction analysis (DARCH diffractometer, λMoK_α, θ/2θ scan mode; 1121 and 2433 unique reflections with F≥4Σ(F), R = 0.064 and 0.044 for I and II, respectively). Ciystals I are orthorhombic, space group Pbnm, Z = 4. a = 21.65(1), b = 11.006(5). c = 11.068(6) Å; ciystals II are triclinic, space group P-l, Z = 2, a = 14.94(1), b = 12.242(8). c = 11.341(7) Å, α = 106.77(5), β = 92.05(6), γ = 113.38(5)°. In contrast to I, the anionic copper acetylenide π-complex contains the propargylium ion whose terminal C? C group acts as a double bridging π, Σ-ligand sim ultaneously bonded to four copper(I) atoms. Structural genesis of [Cu₄Cl₇]^3? _n] (I) and [Cu₈C1₁₀(C = CCH₂OH)]^3? n (II) anions is considered.     

Coordination assemblies of rigid–flexible 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl)propane ligands with MCl<Subscript>2</Subscript> (M = Fe,Co, Cu or Zn): structural diversity and mass spectra

Reactions of the rigid–flexible N-heterocycle 1,3-bis(5-(pyridine-2-yl)-1,2,4-triazole-3-yl) propane (H₂L) with MCl₂ (M = Fe, Co, Cu or Zn) gave coordination complexes, {[Fe ₂ ^III Cl₄(H₂L)₂]·2Cl}·EtOH·H₂O (1), {[Co₃Cl₅(HL)]·H₂O} _n (2), {[Co₄Cl₄(H₂L)₂(H₂O)₄]·[CoCl₄]₂}·H₂O (3), [Cu₂Cl₃(HL)(H₂O)]₆·5H₂O (4), [Cu ₂ ^II Cu^ICl₄(HL)] _n (5), {[Zn₂Cl₂(L)H₂O]·H₂O} _n (6) and [Zn₄Cl₆(HL)₂] (7), which have been characterized by single-crystal X-ray diffraction. Structural analysis reveals that the pyridine triazole ligand attains versatile coordination modes in these complexes. Complexes 1, 3, 4 and 7 consist of 0D clusters with binuclear or tetranuclear units; complex 2 presents a 2D network accompanied by HL^? and chloride bridges; complexes 5 and 6 show 1D chains with [Cu₃] and [Zn₂] subunits. In addition, the electrospray ionization mass spectrometry properties of selected complexes were investigated, revealing the stabilities and structural states of these complexes in solution. These results indicate that H₂L is an excellent multiconnection linker for the construction of diverse coordination complexes.     

Crystal structure and spectroscopic properties of polymeric adducts of the tetra-μ-haloaspirinate-dicopper(II)

Eight new copper(II) complexes with halo-aspirinate anions have been synthesized: [Cu₂(Fasp)₄(MeCN)₂]?·?2MeCN (1), [Cu₂(Clasp)₄(MeCN)₂]?·?2MeCN (2), [Cu₂(Brasp)₄(MeCN)₂]?·?2MeCN (3), {[Cu₂(Fasp)₄(Pyrz)]?·?2MeCN} _n (4), {[Cu₂(Clasp)₄(Pyrz)]?·?2MeCN} _n (5), [Cu₂(Brasp)₄(Pyrz)] _n (6), [Cu₂(Clasp)₄(4,4′-Bipy)] _n (7), and [Cu₂(Brasp)₄(4,4′-Bipy)] _n (8) (Fasp: fluor-aspirinate; Clasp: chloro-aspirinate; Brasp: bromo-aspirinate; MeCN: acetonitrile; Pyrz: pyrazine; 4,4′-Bipy: 4,4′-bipyridine). The crystal structure of two 2 and 4 have been determined by X-ray diffraction methods. All compounds have been studied employing elemental analysis, IR, and UV-Visible spectroscopic techniques. The results have been compared with previous data reported for complexes with similar structures.     

ESR-Untersuchungen an μ-Dichloro-bis[chloro-bis(N,N-diäthyldiselenocarbamato)molybdän(V)]-dichlorid, [Mo2CI4(däsc)4]CI2

EPR-Investigations of α-Dichloro-bis[chloro?bis(N,N?diethyldiselenocarbamato)molybdänum(V)] dichloride, [Mo₂Cl₄(däsc)₄]Cl₂. Preparation and bonding properties of the coordination sphere of [Mo₂Cl₄(däsc)₄]Cl₂ studied by EPR, are reported. The EPR-spectrum at 77°K can be described by an axial symmetric spin-HAMILTONian, the parameters of which are g| = 2.046, g|= 1.996, A| = 53.5 · 10^?4 cm^?1, and A| = 22.8 · 10^?4 cm^?1. No ⁷⁷Se-ligand hyperfine structure could be observed. The very high g-values are explained as being caused by strong ligand spin-orbit interaction, CT-contributions and a high degree of co valency of tho Mo? Se bond. Using an MO-model of the symmetry C_4v, the bonding parameters of the first coordination sphere have been calculated.     

Nieuwland's cuprocatalytic reaction in terms of crystal chemical analysis

Crystallochemical treatment of the Nieuwland reaction is carried out on the basis of structural data obtained for crystalline acetylene complexes of the formulas NH₄Cu₈Cl₉·4C₂H₂·1/2HCu₂Cl₃·H₂O (I), NH₄Cu₃Cl₄·C₂H₂ (II), KCu₈Cl₉·4C₂H₂·1/2HCu₂Cl₃·H₂O (III), KCu₃Cl₄·C₂H₂ (IV), (NH₄)₂Cu₃Cl₅·4/9H₂O·(xC₂H₂) with x=0 (Va), 1/9 (Vb), and 4/9 (Vc) and divinylacetylene (DVA) copper chloride compounds 2CuCl·DVA (VI) and 3CuCl·DVA (VII). Because of the π-coordination of a copper atom, the C≡C bond of the acetylene molecule is activated, as indicated by its significant (up to 1.32 Å) stretch (complexes I and II). The zeolite-like structure of complexes Va-Vc, which form in a catalytic solution, is realized as an infinite {[Cu₁₀₈Cl₁₆₈(H₂O)₁₆]^60?}_n anion with discrete [Cl(NH₄)₆]⁵⁺ cations inside. In this structure, only 16 Cu(1) atoms have a trigonal-pyramidal environment with the oxygen atom of the crystallization water located in the vertex (d_Cu?O=2.79 Å). Under the liquid-phase conditions of the Nieuwland reaction, these copper atoms are active centers stimulating the reaction to the subsequent acetylene oligomerization due to the π-interaction with the C₂H₂ molecule. The mutual arrangement of the catalytically active Cu(1) atoms in structure Va serves as a matrix for the synthesis of DVA, as shown by the structure of the 2CuCl·DVA adduct.     

Mono-, di-, and trinuclear phosphonate oxygen-bridged copper(II) complexes: syntheses,structures, and properties

Reactions of copper salts, zoledronic acid, and 2,2′-bipyridine/1,10-phenanthroline in aqueous ethanolic solutions afforded four phosphonate oxygen-bridged copper complexes, Cu(bipy)(H₄zdn)(HSO₄) (1), [Cu₂(bipy)₂(H₂zdn)(H₂O)(Cl)]·4H₂O (2), [Cu₂(phen)₂(H₂zdn)(H₂O)(Cl)]·2.5H₂O (3), and [Cu₃(bipy)₃(H₄zdn)(H₂zdn)(SO₄)]·5H₂O (4) (H₅zdn = zoledronic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline). The copper centers of 1–4 have square pyramidal coordination geometries. The Cu(II) ions are coordinated to bipy/phen, zoledronate, and HSO₄^?/Cl^? forming mononuclear units for 1, dinuclear for 2 and 3, and trinuclear for 4. These building units are further extended into 3-D supramolecular networks via multiple hydrogen bond interactions. Temperature-dependent magnetic properties of 2 and 4 suggest weak antiferromagnetic coupling (J = ?4.53(8) cm^?1 for 2, J = ?1.69(4) cm^?1 for 4). The antitumor activity of 2 was evaluated against the human lung cancer cell line and indicates effective time- and dose-dependent cytotoxic effects.     

Die Kristallstrukturen von [Cu2Cl2(AA · H+)2](NO3)2 und [AA · H+]Pikr− (AA · H+ = Allylammonium; Pikr− = Pikrat)

The Crystal Structures of [Cu₂Cl₂(AA · H⁺)₂](NO₃)₂ and [AA · H⁺]Picr^? (AA · H⁺ = Allylammonium; Picr^? = Picrat) By an alternating current electro synthesis the crystal-line π-complex [Cu₂Cl₂(AA · H⁺)₂](NO₃)₂ has been obtained from CuCl₂ · 2H₂O, allylamine (AA), and HNO₃ in ethanolic solution. X-ray structure analysis revealed that the compound crystallized in the monoclinic system, space group P2₁/a, a = 7.229(3), b = 7.824(3), c = 26.098(6) Å, γ = 94.46(5)°, Z = 4, R = 0.025 for 2 023 reflections. The crystal structure is built up of Cu_nCl_n chains which are connected by π-bonding bidentate AA · H⁺ …? ON(O)O …? H⁺ · AA units. For comparision with the above complex the structure of [AA · H⁺]Picr^? (Picr^? = picrate anion) is also reported.     

Anion-induced assembly of 2-D Cd(II) complexes with (42·6)(42·63·8) topology based on ferrocenyl dicarboxylate and tripodal ligands

Self-assembly of a flexible tripodal ligand, 1,3,5-tris(1,2,4-triazol-1-ylmethyl)benzene (ttmb) and organometallic carboxylate 1,1'-bis(3-carboxy-1-oxopropyl)-ferrocene (H₂bfcs) with Cd(Ac)₂?·?2H₂O or CdCl₂?·?2.5H₂O yi elds two 2-D binodal (3,4)-connected complexes {[Cd₂(bfcs)(Hbfcs)₂(ttmb)₂]?·?10H₂O} _n (1) and [CdCl(Hbfcs)(ttmb)] _n (2), exhibiting the same topological type (4²?·?6)(4²?·?6³?·?8). Both exhibit a layer structure, which is generated through 1-D undulated ladders connected by organometallic carboxylate, bfcs^2? (in 1), or Cl^? (in 2). Differential pulse voltammetry experiments indicate that half-wave potentials are slightly higher than that of H₂bfcs. Both complexes exhibit similar weak fluorescent emissions at room temperature.     

Dinuclear copper(II) complexes of Fenoprofen: synthesis,spectroscopic, thermal,and SOD-mimic activity studies

Three dinuclear copper(II) complexes with the anti-inflammatory drug Fenoprofen [Hfen, 2-(3-phenoxyphenyl)propionic acid] and nitrogen donors of general formula [Cu₂(fen)₄(L)] _n were prepared from [Cu₂(fen)₄(dmf)₂]·2H₂O (1) [dmf?=?N,N′-dimethylformamide; L?=?4,4′-bipyridine (2), pyrazine (3), and 2,5-dimethylpyrazine (4)]. The new complexes were characterized by chemical analysis, spectroscopic, and thermogravimetric techniques. Antioxidant properties of 1–4 were evaluated for superoxide-dismutase-mimic activity employing the XTT method. Complex 2 presented the highest antioxidant activity (IC₅₀?=?0.260?µmol?L^?1). Anti-inflammatory properties of 2 were evaluated employing carrageenan-induced paw edema in mice, revealing that the Fenoprofen–copper(II) complex containing 4,4′-bipyridine does not present enhanced anti-inflammatory activity compared to the uncomplexed parent drug Fenoprofen calcium salt.     

A density functional theory study of the Cu+·(CO)n (n = 1–3) complexes

Density functional theory calculations, with an effective core potential for the copper ion, and large polarized basis set functions have been used to construct the potential energy surface of the Cu⁺·(CO)_n (n = 1–3) complexes. A linear configuration is obtained for the global minimum of the Cu⁺·CO and Cu⁺·(CO)₂ complexes with a bond dissociation energy (BDE) of 35.9 and 40.0 kcal mol^-1, respectively. For the Cu⁺·(CO)₃ complex, a trigonal planar geometry is obtained for the global minimum with a BDE of 16.5 kcal mol^?1. C-coordinated copper ion complexes exhibit stronger binding energy than O-coordinated complexes as a result of C_lp → 4s σ-donation. The computed sequential BDEs of Cu⁺·(CO)_n (n = 1–4) complexes agree well with experimental findings, in which the electrostatic energy and σ-donation play an important role in the observed trend.     

Synthesis and characterization of CuII and CoII complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPT) by chemical and tribochemical reactions

Four Cu^II and Co^II complexes–[Cu(L₁)Cl₂(H₂O)]3/2H₂O · 1/2EtOH, [Cu(L₁)₂Cl₂]6H₂O, [Co(L₁)Cl₂]3H₂O · EtOH, and [Co₂(L₁)(H₂O)Cl₄]1.5H₂O · EtOH (L₁ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine; TPT)–were synthesized by conventional chemical method and used to synthesize another four metal complexes–[Cu(L₁)I₂(H₂O)]6H₂O, [Cu(L₁)₂I₂]6H₂O, [Co(L₁)I(H₂O)₂]I · 2H₂O, and [Co₂(L₁)I₄(H₂O)₃]–using tribochemical reaction, by grinding it with KI. Substitution of chloride by iodide occurred, but no reduction for Cu^II or oxidation of Co^II. Oxidation of Co^II to Co^III complexes was only observed on the dissolution of Co^II complexes in d₆-DMSO in air while warming. The isolated solid complexes (Cu^II and Co^II) have been characterized by elemental analyses, conductivities, spectral (IR, UV-Vis, ¹H-NMR), thermal measurements (TGA), and magnetic measurements. The values of molar conductivities suggest non-electrolytes in DMF. The metal complexes are paramagnetic. IR spectra indicate that TPT is tridentate coordinating via the two pyridyl nitrogens and one triazine nitrogen forming two five-membered rings around the metal in M : L complexes and bidentate via one triazine nitrogen and one pyridyl nitrogen in ML₂ complexes. In binuclear complexes, L is tridentate toward one Co^II and bidentate toward the second Co^II in [Co₂(L₁)Cl₄]2.5H₂O · EtOH and [Co₂(L₁)I₄(H₂O)₃]. Electronic spectra and magnetic measurements suggest a distorted-octahedral around Cu^II and high-spin octahedral and square-pyramidal geometry around Co^II.     

Indium(III) complexes containing bithiazole derivatives,chloride, methanol,and dimethyl sulfoxide: X‐ray studies,spectroscopic characterization,and thermal analyses

[In(dm4bt)Cl₃(MeOH)]?·?0.5dm4bt (1) (dm4bt is 2,2′‐dimethyl‐4,4′‐bithiazole) and [In(4bt)Cl₃(MeOH)] (2) (4bt is 4,4′‐bithiazole) were prepared from the reaction of 4,4′‐bithiazole and 2,2′‐dimethyl‐4,4′‐bithiazole with InCl₃?·?4H₂O in methanol, respectively. [In(4bt)Cl₃(DMSO)] (3) was also prepared from recrystallization of 2 in DMSO. These complexes were characterized by IR, UV‐Vis, ¹H NMR, ¹³C{¹H} NMR, and luminescence spectroscopy and their structures were studied by single‐crystal X‐ray crystallography. The thermal stabilities of 1 and 3 were studied by thermogravimetric and differential thermal analyses.     

Spectroscopy studies on DNA binding of two ruthenium complexes [Ru(MeIm)4(L)]2+ (L = iip and tip)

Two ruthenium(II) complexes [Ru(MeIm)₄(L)]²⁺ (L?=?2-(imidazo-4-group)-1H-imidazo-[4,5-f][1,10]phenanthroline, 2-(thiophene-2-group)-1H-imidazo[4,5-f][1,10]phenanthroline, MeIm?=?1-methylimidazole) have been synthesized according to literature and structurally characterized. The interaction of the complexes with calf thymus DNA has been explored using electronic absorption titration, competitive binding experiment, circular dichroism, thermal denaturation, and viscosity measurements. The results show that both complexes could bind DNA in a intercalation mode and the DNA-binding affinity of [Ru(MeIm)₄(tip)]²⁺ (K _b?=?(7.2?±?0.3)?×?10⁵?(mol?L^?1)^?1) is greater than that of [Ru(MeIm)₄(iip)]²⁺ (K _b?=?(6.1?±?0.2)?×?10⁵?(mol?L^?1)^?1).     

Effect of collision gas pressure and collision energy on reactions between oxygen and the negative molecular ion of tetrachlorodibenzo-p-dioxins in the collision cell of a triple -quadrupole mass spectrometer

Low-energy reactive collisions between the negative molecular ion of a tetrachlorodibenzo-p-dioxin (TCDD) and oxygen inside the collision cell of a triple-stage quadrupole mass spectrometer produce a substitution ion [M ? Cl + O]^?, a phenoxide ion [C₆H_4-nO₂Cl_n]^?·, [M ? HCl]^?·, and Cl^? by which 1,2,3,4-, 1,2,3,6/1,2,3,7- and 2,3,7,8-TCDD isomers can be distinguished either directly or on the basis of intensity ratios. The collision conditions have an important effect on the relative abundances. Energy- and pressure-resolved curves show that the ions formed by a collisionally activated reaction (CAR) process, i.e. [M ? Cl + O]^? and [C₆H_4-n,O₂Cl_n]^?·, are favoured by a high pressure of oxygen (3-6 mTorr) (1 Torr = 133.3 Pa) and a low collision energy (0.1-7 eV), whereas the ions formed by a collisionally activated dissociation (CAD) process, i.e. [M ? HCl]^?· and Cl^?, are favoured by high pressure and high energy. By choosing a relatively low collision energy (5 eV) and high pressure (4 mTorr), the CAR and CAD ions can be clearly detected.     

Transition metal complexes with cage-opened diamondoid tetracyclo[7.3.1.14,12.02,7]tetradeca-6.11-diene

Cage-opened diamondoid tetracyclo[7.3.1.1^4,12.0^2,7]tetradeca-6,11-diene forms complexes with AgNO₃ and CuCl. The latter crystallized from acetonitrile in polymeric form [Cu₂Cl₂(CH₃CN)(diene)]_n; in the presence of 2,2′-bipyridine, a double-charged monomeric Cu(I)-complex [Cu₂(bipy)₂(diene)]²⁺ formed. Both complexes were structurally characterized through X-ray crystal diffraction analysis.