The structure of di-μ-chloro- bis - {chloro( N,N -diethylethane-1,2-diamine-κ 2)copper(II)}

Dichloro(N,N-diethyl-ethane-1,2-diamine)copper(II) has copper(II) ions in square pyramidal coordination. The two nitrogen atoms of the diamine {Cu–N_primary?=?1.979(3), Cu–N_tertiary?=?2.108(2)?Å} and two chloride ions are in the basal plane {Cu–Cl1?=?2.2680(9), Cu–Cl2?=?2.2989(8)?Å}. A centrosymmetrical dimer di-μ-chloro-bis{chloro(N,N-diethylethane-1,2-diamine-κ²)copper(II)}, C₆H1₆Cl₂CuN₂, is formed by axial coordination by Cl2, trans to the tertiary nitrogen, to a second copper(II) ion, with Cu?···?Cuⁱ?=?3.4855(9) and Cl2–Cuⁱ?=?2.7860(8)?Å. The dimer is also linked by H-bond N1–H?···?Cl1ⁱ.     

A tetranuclear copper(II) complex: crystal structure,assembly, EPR,electrochemistry and magnetism

A tetranuclear copper(II) complex, [Cu₂L]₂(ClO₄)₂ · 4H₂O (1), where H₃L = N,N′-bis(4-(3′-formyl-5′-chlorosalicyclidene)iminoethyl)-4-chloro-2,6-bimethyliminophenol, has been synthesized and structurally characterized by ES-MS, IR and X-ray crystallography. The complex is a dimer of two dinuclear copper(II) acylic enantiomorph subunits ([Cu₂L]ClO₄ · 2H₂O), held together by π–π, coordination and hydrogen bond interactions. The Cu–Cu separation in each subunit, bridged by one phenoxide, is 3.228 Å, and the shortest distance of Cu–Cu between the two subunits is 3.252 Å. There are two crystallographically unique copper(II) environments, one (Cu1) is square-based pyramidal with O₃N₂ donor set, another (Cu2) square planar with O₂N₂ donor set. The cyclic voltammogram of the complex shows that it undergoes two stepwise reduction processes, E _pc = ?0.707 and ?0.850 V, respectively. Magnetic measurements in the 2–300 K range indicate strong antiferromagnetic interactions between Cu(II) ions in each subunit with the exchange constant J = ?211(2) cm^?1. The observation has been rationalized on the basis of the effective magnetic pathway.     

SYNTHESIS AND CRYSTAL STRUCTURE OF OXAMIDATO-BRIDGED BINUCLEAR COPPER(II) COMPLEXES

Abstract

The compounds [Cu(oxpn)] (1), [(bpy)(H₂O)Cu(μ-cis-oxpn)Cu(H₂O)] · 2NO₃ · 2H₂O (2) and [(Him)(NO₃)Cu(μ-trans-oxpn)Cu(Him)(NO₃)] (3), where oxpn is the dianion of N,N′-bis(3-aminopropyl)oxamide, bpy is bipyridine and Him is imidazole, were prepared and characterized by elemental analysis and IR spectra. Complex (2) was also studied by thermochemical analysis and its structure determined by X-ray crystallography. The structure of complex (2) consists of binuclear copper(II) molecules in which the copper(II) atoms are bridged by an oxamidato group in the cis conformation resulting a copper-copper distance of 5.21 Å. Both copper(II) ions are in square-pyramidal surroundings with almost coplanar basal planes and a water molecule occupying the apical positions. The N atoms of the oxamidato moiety are trigonal. Two lattice water molecules together with the two coordinated ones hydrogen bond with nitrate ions.     

Two 2-D copper(II) azido compounds: catena -poly[ di -μ1,1- azido,di -μN,O-(quinolinecarboxylato)(aqua)copper(II)] and 1-D catena -poly[ di -μN,N′-(quinoxaline)copper(II)nitrate]

We synthesized three copper(II) complexes with two structurally related polydentate ligands, quinoline-4-carboxylic acid (quCOOH) and quinoxaline (qux). The structures of these complexes were determined using X-ray single crystal crystallography. Complex 1, [Cu(quCOO)(N₃)(H₂O)] _n , has a 2-D polymeric structure through di-μ_1,1 azido groups forming (Cu₂N₂) dimeric units and di-μ_N,O quinoline carboxylate bridging the binuclear copper units. [Cu(quCOO)(N₃)(H₂O)] _n · 0.87MeOH, (2), has the same structure as 1 in addition to MeOH molecules separating the 2-D sheets of [Cu(quCOO)(N₃)(H₂O)] _n . [Cu(qux)(NO₃)₂] _n , (3), has no coordinated azido groups, but the quinoxaline is a bidentate bridging ligand giving a 1-D chain, while the μ_O,O′ chelating nitrato groups stabilize the chain structure by forming a square planar coordination sphere around copper. IR and UV–Vis spectra of the complexes are in agreement with the crystal structures.     

Synthesis,structure determination,and magnetic properties of pentakis[ bis (hexafluoroacetylacetonato)1,2,4-triazinecopper(II)]

Reaction of bis(hexafluoroacetylacetonato)copper(II) hydrate with 1,2,4-triazine (tz) in dichloromethane yields pentakis[bis(hexafluoroacetylacetonato)triazinecopper(II)] [Cu(hfac)₂(tz)]₅ (hfac = hexafluoroacetylacetonate) (1). The complex crystallizes in the triclinic space group P-1, with cell parameters a = 11.4124(5), b = 13.3405(5), c = 16.1794(7) Å, α = 93.360(2)°, β = 108.700(2)°, γ = 100.293(2)° at 120(1) K. In the complex, the copper(II) ions show three types of coordination polyhedra: square planar, square pyramidal, and octahedral (4 + 2). The tz ligand also shows different coordination modes (bridging and monodentate). In addition, disorder is observed in the triazine molecule, either through non-crystallographic two-fold rotation about the longitudinal N,N-axis, or with respect to a crystallographic center of symmetry. The crystal structure of 1 consists of alternating trimers and dimers. The weak coordination of the tz molecules results in negligible magnetic exchange through the ring.     

Magnetic interactions in a new heterospin complex involving nitroxide radical and oxamido-bridged copper(II)

A new binuclear copper(II) complex [Cu₂(oxpn)(IM2py)₂](ClO₄)₂, containing four spin carriers with pyridyl-substituted nitroxide radicals has been synthesized and characterized structurally and magnetically (oxpn?=?N,N′-bis(3-aminopropyl)oxamido, IM2py?=?2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl). The structure of the complex consists of centrosymmetric trans oxamido-bridged copper(II) binuclear units and nitroxide radicals. The coordination geometry around each copper atom is distorted square pyramidal and the apical position is occupied by a nitrogen atom of the imidazoline ring of a radical ligand. Magnetic analysis indicates that the complex exhibits strong antiferromagnetic coupling between copper(II) ions through the oxamido bridge and a ferromagnetic interaction between copper(II) ions and radical ligands. The magnetic behaviour is discussed with reference to the crystal structure.     

TRANSITION METAL COMPLEXES WITH HYDRAZIDES AND HYDRAZONES. PART 81. X-RAY CRYSTAL STRUCTURE OF A CATENA-POLYBROMO (ACETONE-1-NAPHTHOYLHYDRAZONE) COPPER(II)-COPPER(I) COMPLEX

Abstract

The title compound [Cu₃Br₄C₂₈H₂₈N₄O₂] is a type of polymeric three-centre octahedral-trigonal planar coordination complex. The copper(II) atom located at a centre of symmetry is six-coordinate with two bidentate (N3, O1) ligands of acetone-1-naphthoylhydrazone forming the equatorial plane and two bromine ions in axial positions (Cul-Brl = 2.946(1)Å). The ligands are in trans positions. The Cu(I) atoms are in trigonal planar coordination by two bridging Br^? ions (Cu2-Br2 = 2.412(1)Å, Cu2-Br2? = 2.407(2)Å) which connect two Cu(I) atoms and a third bromine ion shared with the octahedral Cu(II) ion (Cu2-Br1 = 2.304(1)Å). The arrangement forms an infinite chain along the b axis.     

Synthesis,crystal structure,and DNA-binding studies of a one-dimensional copper(II) polymer bridged both by oxamidate and thiocyanato ligands

A new one-dimensional copper(II) polymer, [Cu₄(dmapox)₂(SCN)₄(CH₃OH)₂] _n , where dmapox is the dianion of N,N′-bis[3-(dimethylamino)propyl]oxamide, was synthesized and characterized by elemental analysis, conductivity measurement, IR, and electronic spectral studies. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The complex crystallizes in triclinic, space group P ? 1 and exhibits infinite one-dimensional copper(II) polymeric chain bridged both by bis-tridentate μ-trans-dmapox and μ-1,3-thiocyanato ligand. The environment around the copper(II) atom can be described as distorted square-pyramid. The Cu···Cu separations through the oxamidate and thiocyanato bridges are 5.246(2) Å (Cu1–Cu1ⁱ), 5.2649(14) Å (Cu2–Cu2ⁱⁱ), and 5.8169(15) Å (Cu1–Cu2), respectively. The interaction of the copper(II) complex with herring sperm DNA (HS-DNA) has been investigated by using absorption and emission spectral and electrochemical techniques and viscometry. The results reveal that the copper(II) complex may interact with DNA in the mode of groove binding with the intrinsic binding constant of 2.56 × 10⁵ M^?1.     

Synthesis,structure, and DNA-binding of a new binuclear copper(II) complex: [Cu2(heap)(H2O)2](pic)2 · 2H2O

In this study, a new μ-oxamido-bridged binuclear copper(II) complex [Cu₂(heap)(H₂O)₂](pic)₂ ? 2H₂O, where heap and pic stand for the anion of N,N′-bis(N-hydroxyethylaminopropyl)oxamide and 2,4,6-trinitrophenol, respectively, has been synthesized and characterized by elemental analyses, IR, UV, molar conductance, and single-crystal X-ray diffraction. The complex has an embedded inversion center at the middle of the C–C bond of the oxamido group. Each copper(II) is in a square-pyramidal coordination geometry. The bridging ligand (heap) adopts a bis-tetradentate trans conformation and the oxamido group is in an imidic acid configuration. Hydrogen bonds contribute to a 3-D supramolecular structure in the crystal. The interaction of the binuclear complex with herring sperm deoxyribonucleic acid (HS-DNA) has been investigated by using absorption and emission spectra, electrochemical techniques, and viscometry. The results suggest that the binuclear copper(II) complex interacts with HS-DNA by electrostatic interaction with intrinsic binding constant of 2.67 × 10⁴ (mol L^?1)^?1. The influence of anions on the structure and the interaction of the binuclear complex with HS-DNA were preliminarily discussed.     

Synthesis and crystal structure of a new copper(II) binuclear complex bridged by the reduced derivative of a nitronyl nitroxide biradical

A new copper(II) binuclear complex, [Cu(hfac)₂]₂(IMH)₂Ph(OMe)₂ ((IMH)₂Ph(OMe)₂?=?2,5-dimethoxyl-1,4-bis(4′,4′,5′,5′-tetramethylimidazoline-3′-oxide)benzene, hfac?=?hexafluoroacetonate), bridged by a reduced derivative of a nitronyl nitroxide biradical has been synthesized and characterized by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/n, with a?=?10.002(14), b?=?19.950(3), c?= 14.504(2) Å, β?=?108.842(3)° and Z?=?2. The structure refined to a final R value of 0.0644. The complex contains two copper(II) ions bridged by a reduced derivative of a nitronyl nitroxide biradical with a Cu?···?Cu separation of 8.430(2) Å.     

Phenomenon of <Emphasis Type="Italic">trans-cis</Emphasis> isomerization of copper(II) β-diketonate on co-crystallization with lead(II) hexafluoroacetylacetonate

X-ray diffraction structural study is carried out for crystals of a heterobimetallic complex derived from lead(II) hexafluoroacetylacetonate and copper(II) 2-methoxy-2,6,6-trimethylheptan-3,5-dionate prepared by co-crystallization of Pb(hfa)₂ and trans-Cu(zis)₂. In the novel compound Cu(zis)₂·Pb(hfa)₂ the copper complex is found to have cis-configuration. It is demonstrated that the main structural motif of this complex is coordination dimers Cu(zis)₂·Pb(hfa)₂ joint in polymeric chains of alternating molecules of the complexes. Crystal data for Cu(zis)₂·Pb(hfa)₂: a = 9.848(2) Å, b = 23.871(5) Å, c = 18.289(4) Å, β = 100.23(3)°, space group P2₁/n, Z = 4, d _x = 1.701 g/cm³. The distance Pb-Cu in the dimer is 3.68 Å.     

A binuclear copper(II) complex with unusual magnetism

A binuclear copper(II) complex [Cu₂ (μ-pyo)₂Br₄] _n (where pyo = pyridine N-oxide) has been synthesized and its structure determined by X-ray crystallography. This complex crystallizes in monoclinic, space group P2₁/c, with unit cell dimensions a = 11.020(3) Å, b = 10.049(3) Å, c = 7.905(2) Å, β = 110.609(3)°, and Z = 2. The structure was refined to final R = 0.0311 and wR = 0.0721 for 1302 observed reflections (I > 2σ(I)). In the complex, two Cu(II) ions are bridged by two pyo ligands and four bromides coordinate the Cu(II); the distance between the bridged Cu(II) ions is 3.261 Å. The variable-temperature (4–300 K) magnetic susceptibility data show that the magnetic moment is zero. Thus, there exists very strong anti-ferromagnetic coupling between the bridged binuclear Cu(II) ions. Density functional calculations yield a singlet-triplet splitting 2J = ?1355 cm^?1.     

catena‐Poly­[[trans‐bis­(ethane‐1,2‐di­amine‐κ2N,N′)copper(II)]‐μ‐di­thion­ato‐κ2O:O′] and trans‐di­aqua­bis­(propane‐1,3‐di­amine‐κ2N,N′)copper(II) di­thionate

In title an­hydro­us catena‐poly­[[trans‐bis­(ethane‐1,2‐di­amine‐κ²N,N′)copper(II)]‐μ‐di­thionato‐κ²O:O′], [Cu(S₂O₆)(C₂H₈N₂)₂]_n or [{H₂N(CH₂)₂NH₂}₂Cu(O·O₂SSO₂·O)]_∞, successive Cu atoms are bridged by a single doubly charged di­thionate group, forming a one‐dimensional polymer with inversion centres at the metal atoms and the mid‐point of the S—S bond [Cu—O = 2.5744 (15) Å]. In title (hydrated) trans‐di­aqua­bis­(propane‐1,3‐di­amine‐κ²N,N′)copper(II) di­thionate, [Cu(C₃H₁₀N₂)₂(H₂O)₂](S₂O₆) or [{H₂N(CH₂)₃NH₂}₂Cu(OH₂)₂](S₂O₆), both ions have imposed 2/m symmetry. The `axial' anion components are displaced by a pair of water ligands [Cu—O = 2.439 (3) Å], the shorter Cu—O distance being compensated by the lengthened Cu—N distance [2.0443 (18), cf. 2.0100 (13) and 2.0122 (16) Å].     

Syntheses and crystal structures of cis - and trans -copper(II) complexes of L-arginine

Two copper(II) complexes of L-arginine, trans-[Cu(l-Arg)₂(NO₃)]NO₃ · 3H₂O (1) and {cis-[Cu(l-Arg)₂](NO₃)₂ · 3H₂O} _n (2) (Arg = arginine) were prepared by reaction of Cu(NO₃)₂ · 3H₂O and L-arginine in acetone and aqueous solution, respectively. X-ray analysis reveals 1 crystallizes in a monoclinic system, P2₁ with a = 10.3857(15), b = 16.885(3), c = 15.9586(19) Å, β = 15.9586(19)°, Z = 4, V = 2654.2(6) ų. The copper(II) centers lie in a distorted N₂O₃ square-pyramidal environment. While 1 adopts a mononuclear structure, and the axial position occupied by a nitrate with Cu1–O9 = 2.535 Å and Cu2–O20 = 2.581 Å, 2 features a 1-D infinite chain structure. In 1, adjacent monomeric units connect with each other to give a 2-D layer structure of (4, 4) nets through hydrogen bonds between the guanidinium and carboxylic groups of arginine, and 2-D layers further assemble to a 3-D supermolecular structure via a series of inter-layer hydrogen bonds.     

Spacer-armed binuclear copper(ii) complexes with salicylidene hydrazones of N-benzoylaminodicarboxylic acids

The structure and EPR spectra of copper(II) complexes with bis(salicylidene)hydrozones of N-benzoyl-L-aspartic and N-benzoyl-L-glutamic acids have been described. The compounds have been studied by chemical and thermal analyses, IR spectroscopy, and EPR spectroscopy. The molecular and crystal structure of the copper(II) complex with bis(salicylidene)hydrozone of N-benzoyl-L-aspartic acid (H₄L) of composition [Cu₂L · 2Py] · 2CH₃OH · H₂O has been determined by X-ray single-crystal diffraction. The crystals are monoclinic: a = 10.3316(7) Å, b = 16.7552(9) Å,c = 11.0137(6) Å, β = 105.758(3)°, space group P2₁, Z = 2. The complex has a polymeric structure composed of alternating copper-containing binuclear fragments bound to each other either via phenoxy bridges or via an aliphatic spacer (the Cu…Cu distances are 3.471 Å and 8.939 Å, respectively). The EPR spectra of the solutions of the complexes under study shows an isotropic signal comprising seven HFS lines due to two equivalent copper nuclei with the spin Hamiltonian parameters g = 2.115–2.122 and a _Cu = (36.1–36.9) × 10^?4 cm^?1, which indicates the reaization of weak exchange coupling of the paramagnetic centers.     

Binuclear copper(II) complexes with acyldihydrazones of <Emphasis Type="Italic">N</Emphasis>-benzenesulfonyl-<Emphasis Type="Italic">L</Emphasis>-aspartic acid

The structure and the EPR spectra of copper(II) coordination compounds with acyldihydrazones of N-benzenesulfonyl-L-aspartic acid and salicylaldehyde (2-hydroxyacetophenone) were described. The compounds were studied by chemical and thermal analyses, IR spectroscopy, and EPR. The molecular and crystal structures of copper(II) complexes with N-benzenesulfonyl-L-aspartic acid bis(salicylidene)hydrazone (H₄L¹) [Cu₂L¹ · 2Py] · 1.5 H₂O was determined by X-ray diffraction. The crystals are triclinic: a = 10.4714(4) Å, b = 12.9702(5) Å, c = 14.6187(9) Å, α = 104.763(2)°, β = 93.082(2)°, γ = 111.4240(10)°, space group P \(\bar 1\), Z = 2. The binuclear complexes containing copper cations whose coordination polyhedra are connected by an aliphatic spacer (Cu...Cu, 8.669 Å) are additionally linked by phenoxy bridges (Cu...Cu, 3.398 Å). The EPR spectra of these compounds in solutions exhibit an isotropic signal of seven HFS lines due to two equivalent copper ions with the spin Hamiltonian parameters g = 2.115?2.120, a _Cu = (35.5?38.0) × 10^?4 cm^?1, which is indicative of weak exchange interactions between the paramagnetic sites.     

Bis­(di‐2‐pyridyl­phosphinato‐κ3N,O,N′)copper(II) di­chloro­methane disolvate

The solid‐state structure of the first reported homoleptic copper di‐2‐pyridyl­phosphinate complex shows an extremely large `z‐out' tetragonal distortion, with an axial Cu⋯O distance of 2.430 (2) Å. The title complex, [Cu(C₁₀H₈N₂O₂P)₂]·2CH₂Cl₂ or Cu[py₂P(O)O]₂·2CH₂Cl₂, comprises two di‐2‐pyridyl­phosphinate ligands coordinated to the central copper(II) ion, which sits on an inversion center. The pyridyl rings of one ligand are trans to the pyridyl rings of their symmetry‐related counterpart. The two trans py–Cu–py moieties are coplanar, as required by the inversion symmetry. A disordered dichloromethane solvent mol­ecule is cocrystallized in the asymmetric unit cell.     

Synthesis, characterization, crystal structure and antitumor activities of a novel demethylcantharidato bridged copper(II) phenanthroline complex

A new polymeric demethylcantharidato (DCA) bridged copper(Ⅱ) phenanthroline (phen) complex ([Cu(DCA)(phen)] n ·nH2O) has been synthesized and characterized by elemental analysis, IR and electronic spectra studies, molar conductivity measurement, and single crystal X-ray diffraction. The complex crystallizes in the orthorhombic space group Pbca with crystallographic data: a = 12.4537(4), b = 9.3897(5), c = 30.1264(10), and Z = 8. In the crystal structure, the octahedral coordinated copper(Ⅱ) ions are bridged by demethylcantharidate ligands into a one-dimensional zigzag-like structure with the Cu···Cu separation of 6.1719, along with phen ligands attached to both sides of the chain alternatively. Interdigitation of the chelating phen ligands of two neighboring chains via hydrophobic interaction and van der Waals forces along ac plane forms two-dimensional polymeric bilayers with discrete water sandwich layer between the adjacent polymeric bilayers. The evaluation of the cytotoxic activity of the copper(Ⅱ) complex against HCT-8 (colorectal carcinoma), A549 (pulmonary carcinoma), HeLa (cervical cancer), HepG2 (hepatocarcinoma), BGC-823 (gastric carcinoma), and MCF-7 (breast adenocarcinoma) cell lines revealed that it is a potent cytotoxic agent, superior to Na2DCA and phen against HeLa, HepG2 and BGC-823 cells.     

Dinuclear copper(II) complex and 1-D copper(II) complex with taurine Schiff base: synthesis,crystal structure,and properties

A dinuclear copper(II) compound, [Cu(btssb)(H₂O)]₂ · 4(H₂O) (1), and a 1-D chain copper(II) compound, [Cu(ctssb)(H₂O)] _n (2) [where H₂btssb is 2-[(5-bromo-2-hydroxy-benzylidene)-amino]-ethanesulfonic acid and H₂ctssb is 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-ethanesulfonic acid], were prepared and characterized. Compound 1 crystallizes in the monoclinic space group P2₁/c, with a = 10.109(2) Å, b = 20.473(4) Å, c = 6.803(1) Å, β = 100.32(3)°, V = 1385.1(5) ų, and Z = 2; R ₁ for 1796 observed reflections [I > 2σ(I)] was 0.0357. The geometry around each copper(II) can be described as slightly distorted square pyramidal. The Cu^II ··· Cu^II distance is 5.471(1) Å. Compound 1 formed a 1-D network through O–H ··· O hydrogen bonds and 1-D water chains exist. The 1-D chain complex 2 crystallizes in the triclinic space group P 1, with a = 5.030(2) Å, b = 7.725(2) Å, c = 17.011(5) Å, α = 92.706(4)°, β = 97.131(4)°, γ = 102.452(3)°, V = 638.6(3) ų, and Z = 2; R ₁ for 1897 observed reflections [I > 2σ(I)] was 0.0171. In 2, Cu(II) was also a slightly distorted square pyramid formed by two oxygens and one nitrogen from ctssb, one oxygen from another ctssb, and one water molecule. The complex formed a 1-D chain through O–S–O bridge of ctssb ligand. The 1-D chain further constructed a double chain through O?H ··· O hydrogen bonds.     

Crystal structure and properties of a Cu(II) complex with the tridentate Schiff-base ligand,paeonol-(2-aminoethylpiperazine)

A new copper Schiff-base complex [Cu(C₁₅H₂₃N₃O₂)(NO₃)]NO₃ was synthesized and characterized by spectroscopic (IR), thermal (TG/DTA) and electrochemical methods. Single crystal X-ray diffraction revealed that the complex is monoclinic, space group P2(1)/c, with a = 23.549(2), b = 6.583(12), c = 12.765(15) Å, β = 102.823(2)°, V = 1929.4(5) ų, Z = 4, D _calcd = 1.601 Mg m^?3, F(000) = 964, goodness-of-fit = 1.034 and R ₁ = 0.0407. The Cu(II) is four-coordinate with distorted square planar geometry. The structure consists of isolated [Cu(C₁₅H₂₃N₃O₂)(NO₃)]⁺ and a nitrate, which are further linked to a 3D network by significant N–H ··· O, N–H ··· N hydrogen bonds and weak O ··· Cu interaction.