Cu-O Distances Research Articles

Crystal structures, electron spin resonance, and thermogravimetric analysis of three mixed-valence copper cyanide polymers.

The crystal structures of three mixed-valence copper cyanide alkanolamine polymers are presented, together with thermogravimetric analysis (TGA) and electron spin resonance (ESR) data. In all three structures, a CuII moiety on a crystallographic center of symmetry is coordinated by two alkanolamines and links two CuICN chains via cyanide bridging groups to form diperiodic sheets. The sheets are linked together by cuprophilic CuI-CuI interactions to form a three-dimensional network. In poly[bis(μ-3-aminopropanolato)tetra-μ-cyanido-dicopper(I)dicopper(II)], [Cu4(CN)4(C3H8NO)2]n, 1, propanolamine bases have lost their hydroxyl H atoms and coordinate as chelates to two CuII atoms to form a dimeric CuII moiety bridged by the O atoms of the bases with CuII atoms in square-planar coordination. The ESR spectrum is very broad, indicating exchange between the two CuII centers. In poly[bis(2-aminopropanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(C3H9NO)2]n, 2, and poly[bis(2-aminoethanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(CH7NO)2]n, 3, a single CuII atom links the CuICN chains together via CN bridges. The chelating alkanolamines are not ionized, and the OH groups form rather long bonds in the axial positions of the octahedrally coordinated CuII atoms. The coordination geometries of CuII in 2 and 3 are almost identical, except that the Cu-O distances are longer in 2 than in 3, which may explain their somewhat different ESR spectra. Thermal decomposition in 2 and 3, but not in 1, begins with the loss of HCN(g), and this can be correlated with the presence of OH protons on the ligands in 2 and 3, which are not present in 1.

Structural Disorder of CuO, ZnO, and CuO/ZnO Nanowires and Their Effect on Thermal Conductivity

In this work, the structural defects and the thermal conductivity of CuO, ZnO, and CuO/ZnO nanowires have been studied, using molecular dynamics simulation with COMB3 potential. The initial parameters and atoms positions were taken from reports of bulk materials with tenorite and wurtzite structures, respectively. Nanowires were grown along the c-axis, as observed experimentally. The results confirm the defects apparition in the systems after simulation with a formation of grains to reduce the energy of the nanowires. In the CuO nanowires case, the lack of periodicity in the basal plane causes a contraction effect over the network parameter b of the monoclinic structure with a Cu-O distance reduction. [A constriction effect on inclined planes, as a product of surface charges, deforms the nanowire, generating undulations. In ZnO nanowires, a decrease in the Zn-Zn distance produced a contraction in the nanowire length. A constriction effect was evident on the surface charges. It presented a bond reduction effect, which was larger at the ends of the nanowire. In CuO/ZnO nanowires, the structural defects come from the distortions of the crystalline lattice of the ZnO rather than CuO. The thermal conductivity of the nanowires was calculated at temperatures between 200 K and 600 K using the Green–Kubo equation. Results showed similar values to those reported experimentally, and the characteristic maximum with similar trends to those observed in semiconductors. Our results suggest that structural defects appear in nanowires grown on the free substrate, and are not related to the lattice mismatch.

Nonadiabatic coupling of the dynamical structure to the superconductivity in YSr2Cu2.75Mo0.25O7.54 and Sr2CuO3.3

A crucial issue in cuprates is the extent and mechanism of the coupling of the lattice to the electrons and the superconductivity. Here we report Cu K edge extended X-ray absorption fine structure measurements elucidating the internal quantum tunneling polaron (iqtp) component of the dynamical structure in two heavily overdoped superconducting cuprate compounds, tetragonal YSr2Cu2.75Mo0.25O7.54 with superconducting critical temperature, Tc = 84 K and hole density p = 0.3 to 0.5 per planar Cu, and the tetragonal phase of Sr2CuO3.3 with Tc = 95 K and p = 0.6. In YSr2Cu2.75Mo0.25O7.54 changes in the Cu-apical O two-site distribution reflect a sequential renormalization of the double-well potential of this site beginning at Tc, with the energy difference between the two minima increasing by ∼6 meV between Tc and 52 K. Sr2CuO3.3 undergoes a radically larger transformation at Tc, >1-Å displacements of the apical O atoms. The principal feature of the dynamical structure underlying these transformations is the strongly anharmonic oscillation of the apical O atoms in a double-well potential that results in the observation of two distinct O sites whose Cu-O distances indicate different bonding modes and valence-charge distributions. The coupling of the superconductivity to the iqtp that originates in this nonadiabatic coupling between the electrons and lattice demonstrates an important role for the dynamical structure whereby pairing occurs even in a system where displacements of the atoms that are part of the transition are sufficiently large to alter the Fermi surface. The synchronization and dynamic coherence of the iqtps resulting from the strong interactions within a crystal would be expected to influence this process.

Desymmetrization in geometry optimization: application to an ab initio study of copper(I) hydration

Abstract Group theoretical arguments are used to find the subgroup corresponding to symmetry reduction along a particular irreducible representation of a group. The results are used to guide the search for stationary points on the potential energy surface of hydrated copper(I) ion at the HF/6-31G∗, HF/6-31+G∗, HF/6-311+G∗, MP2/6-31G∗, MP2/6-31+G∗, MP2/6-311+G∗, B3LYP/6-31G∗, B3LYP/6-31+G∗, and B3LYP/6-311+G∗ levels. The better levels give the most stable coordination number of two. The effect of desymmetrization on the Cu-O distances and stretching frequencies has been examined.

Interplay between local structure, vibrational and electronic properties on CuO under pressure.

The electronic and local structural properties of CuO under pressure have been investigated by means of X-ray absorption spectroscopy (XAS) at Cu K edge and ab initio calculations, up to 17 GPa. The crystal structure of CuO consists of Cu motifs within CuO4 square planar units and two elongated apical Cu-O bonds. The CuO4 square planar units are stable in the studied pressure range, with Cu-O distances that are approximately constant up to 5 GPa, and then decrease slightly up to 17 GPa. In contrast, the elongated Cu-O apical distances decrease continuously with pressure in the studied range. An anomalous increase of the mean square relative displacement (EXAFS Debye-Waller, σ2) of the elongated Cu-O path is observed from 5 GPa up to 13 GPa, when a drastic reduction takes place in σ2. This is interpreted in terms of local dynamic disorder along the apical Cu-O path. At higher pressures (P > 13 GPa), the local structure of Cu2+ changes from a 4-fold square planar to a 4+2 Jahn-Teller distorted octahedral ion. We interpret these results in terms of the tendency of the Cu2+ ion to form favorable interactions with the apical O atoms. Also, the decrease in Cu-O apical distance caused by compression softens the normal mode associated with the out-of-plane Cu movement. CuO is predicted to have an anomalous rise in permittivity with pressure as well as modest piezoelectricity in the 5-13 GPa pressure range. In addition, the near edge features in our XAS experiment show a discontinuity and a change of tendency at 5 GPa. For P < 5 GPa the evolution of the edge shoulder is ascribed to purely electronic effects which also affect the charge transfer integral. This is linked to a charge migration from the Cu to O, but also to an increase of the energy band gap, which show a change of tendency occurring also at 5 GPa.

Calculating the geometry and Raman spectrum of physiological bis(L-histidinato)copper(II): an assessment of DFT functionals for aqueous and isolated systems.

Reliable density functional theory (DFT) calculations can be performed in conjuction with spectroscopic measurements to elucidate the structural properties of physiologically important bis(amino acidato)copper(II) compounds in solutions. They can provide insight into the influence of intermolecular interactions on the molecular geometry in the crystal lattice or solution when compared with a DFT gas-phase minimum. Our previous paper [Marković et al. (2014) Eur J Inorg Chem 198] reported the DFT-determined geometries and Raman spectra for different conformers of physiological bis(L-histidinato)copper(II) with 20 explicit water molecules, as calculated using the B3LYP functional. The present study examined the reliability of those B3LYP results by applying the M06 functional instead, as it should better account for noncovalent interactions. The water molecules were positioned more compactly around the complex by M06 than by B3LYP. The accuracies of the two functionals when compared to relevant experimental data showed that M06 was better at reproducing in-plane Cu-N bond lengths but B3LYP gave more accurate axial Cu-O distances. Both functionals reproduced the experimental Raman spectrum at pH8 to similar levels of accuracy and provided precise information on the Cu(II) coordination mode and conformation in aqueous solution. Additionally, we assessed several DFT and DFT-D functionals (BP86, B3LYP, B3LYP-D, M06, M06L, wB97XD, mPW2PLYPD) by using them to model the geometries of experimental bis(L-histidinato)copper(II) crystalline conformationsas isolated systems, and then benchmarking the results against those from high-level second-order pertubation Møller-Plesset (MP2) calculations. Although this assessment resulted in an equivocal conclusion because the MP2 results for the isolated complex were inconsistent with the corresponding DFT outcomes, it does provide new information on future benchmark options.

High-Tc Superconducting Cuprates, (Ce,Y)sO2s-2Sr2(Cu2.75Mo0.25)O6+δ: Tc-increase with apical Cu-O decrease at constant Cu-O planar distance

Evidence for high-Tc cuprate superconductivity is found in a region of the phase diagram where non-superconducting Fermi liquid metals are expected. Cu valences estimated independently from both XANES measurements and bond valence sum calculations are greater than 2.25 and are in close agreement with each other for structures of the homologous series given in the title with s = 1, 2, 3, 4 and 5. Two questions arise from the present perspective: 1) Is all the action in the CuO2 layers? 2) Is there superconductivity beyond the usual dome? The record short apical oxygen distance found in the homologous series especially in the s = 1 member, at odds with the current theory, suggests the possibility of a new pairing mechanism. The apical Cu-O distance in the s = 1 member decreases upon oxygenation from 2.29 to 2.15 Ȧ while the Cu valence increases to 2.45 Ȧ.

Remarkable transition from rocksalt/perovskite layered structure to fluorite/rocksalt layered structure in rapidly cooled Ln2CuO4

Lanthanide cuprates of formula Ln2CuO4 exist in two principal forms, T and T′ which are renowned for their exhibition at low temperatures of hole and electronic types of superconductivity, respectively. These structures differ primarily in the arrangement of oxygen between the perovskite layers and also in nature of the copper oxygen planes. The Cu-O distance in the T structure (~1.90 Å) is much shorter than the T′ (1.97Å), reflecting a transition between partial Cu+ and partial Cu3+ character. In seeking to find compositions that bridge these two structure/electron carrier types, we observed the transition from a T structure to a T′ type structure, resulting in the metastable form T″ with slightly larger volume but similar character to T′. This transition from T to T″ is associated with 5% increase in a and a 5% decrease in c parameters of the tetragonal unit cells, which results in disintegration of ceramic bodies.

A study of the structure and properties of mixed-ligand Cu(II) complexes with hexafluoroacetylacetone and methyl-, phenyl-ketoimines

The synthesis and X-ray single crystal study of two mixed-ligand Cu(II) complexes are performed: (CH3C(NCH3)CHC(O)CH3)(CF3C(O)CHC(O)CF3)Cu (1) (space group P21/c, a = 7.0848(12) A, b = 17.854(3) A, c = 11.837(2) A, β = 100.495(6)°, V = 1472.4(4) A3, Z = 4), (CH3C(NC6H5)CHC(O)CH3)· (CF3C(O)CHC(O)CF3)Cu (2) (space group P-1, a = 9.1119(4) A, b = 9.6954(4) A, c = 11.1447(6) A, α = 113.784(2)°, β = 92.383(2)°, γ = 95.402(2)°, V = 893.52(7) A3, Z = 2). The structures are molecular, formed from neutral mixed-ligand copper complexes. The central copper atom has the (3O+N) coordination environment with average Cu-O distances of 1.948 A and Cu-N of 1.932 A; the chelate O-Cu-N angle (average) is 94.0°. In the structures, the complexes are linked into dimeric associates with Cu…Cu distances of 3.197 A (for 1) and 3.246 A (for 2). The volatility of mixed-ligand complexes 1 and 2 is in between of that of the starting homo-ligand complexes.

Isolable, Copper(I) Dicarbonyl Complexes Supported by N-Heterocyclic Carbenes

Cationic copper(I) dicarbonyl complexes supported by N-heterocyclic carbene ligands, SIPr and IPr*, have been synthesized. [(SIPr)Cu(CO)(2)][SbF(6)] and [(IPr*)Cu(CO)(2)][SbF(6)] have a trigonal planar, three-coordinate copper atom with an average Cu-CO distance of 1.915 Å and display C-O stretching frequencies higher than that of the free CO (2143 cm(-1)). The high CO stretching frequencies suggest that the Cu(I)-CO interaction in these cationic adducts is dominated by electrostatic and OC → Cu σ-donor components. [(SIPr)Cu(CO)(2)][SbF(6)] and [(IPr*)Cu(CO)(2)][SbF(6)] readily form the corresponding [(SIPr)Cu(CO)(H(2)O)][SbF(6)] and [(IPr*)Cu(CO)(H(2)O)][SbF(6)] with loss of a CO even with traces of water, but they can be converted back to the dicarbonyl adducts using excess CO. The synthesis and structure of [(IPr*)Cu(H(2)O)][SbF(6)] are also reported. It is a two-coordinate copper adduct with a Cu-O distance of 1.874(2) Å. It reacts with excess CO to form [(IPr*)Cu(CO)(2)][SbF(6)].

Structural Observations of Heterometallic Uranyl Copper(II) Carboxylates and Their Solid‐State Topotactic Transformation upon Dehydration

The hydrothermal reactions of uranyl nitrate and metallic copper with aromatic polycarboxylic acids gave rise to the formation of five heterometallic UO(2)(2+)-Cu(2+) coordination polymers: (UO(2))Cu(H(2)O)(2)(1,2-bdc)(2) (1; 1,2-bdc = phthalate), (UO(2))Cu(H(2)O)(2)(btec)⋅4 H(2)O (2) and (UO(2))Cu(btec) (2'; btec = pyromellitate), (UO(2))(2)Cu(H(2)O)(4)(mel) (3; mel = mellitate), and (UO(2))(2)O(OH)(2)Cu(H(2)O)(2)(1,3-bdc)⋅H(2)O (4; 1,3-bdc = isophthlalate). Single-crystal X-ray diffraction (XRD) analysis of compound 1 revealed 2D layers of chains of UO(8) and CuO(4)(H(2)O)(2) units that were connected through the phthalate ligands. In compound 2, these sheets were connected to each other through the two additional carboxylate arms of the pyromellitate, thus resulting in a 3D open-framework with 1D channels that trapped water molecules. Upon heating, free and bonded water species (from Cu-OH(2)) were evacuated from the structure. This thermal transition was followed by in situ XRD and IR spectroscopy. Heating induced a solid-state topotactic transformation with the formation of a new set of Cu-O interactions in the crystalline anhydrous structure (2'), in order to keep the square-planar environment around the copper centers. The structure of compound 3 was built up from trinuclear motifs, in which one copper center, CuO(4)(OH(2))(2), was linked to two uranium units, UO(5)(H(2)O)(2). The assembly of this trimer, "U(2)Cu", with the mellitate generated a 3D network. Complex 4 contained a tetranuclear uranyl core of UO(5)(OH)(2) and UO(6)(OH) units that were linked to two copper centers, CuO(OH)(2)(H(2)O)(2), which were then connected to each other through isophthalate ligands and U=O-Cu interactions to create a 3D structure. The common structural feature of these different compounds is a bridging oxo group of U=O-Cu type, which is reflected by apical Cu-O distances in the range 2.350(3)-2.745(5) Å. In the case of a shorter Cu-O distance, a slight lengthening of the uranyl bond (U=O) is observed (e.g., 1.805(3) Å in complex 4).

Crystal structure of a new copper(II) complex with borodicitric acid

The crystal structure of the double copper(II) complex with borodicitric acid [Cu(H2O)5(C6H6O7)2B]+ · [(C6H6O7)2B]− · 5H2O of composition Cu[(C6H6O7)2B]2 · 10H2O has been studied by X-ray crystallography. The crystals are monoclinic, space group P21): a = 10.7852(2) A, b = 9.9980(2) A, c = 17.9500(5) A; β = 101.126(1)°, FW = 1025.75, V = 1899.18(7) A3, Z = 2. The dicitratoborate anions with a spirane structure have a normal geometry. The coordination polyhedron of the copper atoms is a distorted octahedron (CN 6 = 4 + 2) with an average equatorial Cu-O distance of 1.965 ± 0.023 A. The axial positions in the CuO6 octahedron are occupied by a water molecule and an oxygen atom of one of the citrate ligands: Cu-O(5w), 2.430(3) A; Cu-O(8), 2.382(3) A. The crystals have an extended intricate system of hydrogen bonds consisting of 27 unique three-center O-H…O, O(w)…O, and O(w)…O(w’) bonds and four-center O(w)…O, O(w’) bonds with different structural functions.

Aquatrichlorido(1-cyanomethyl-4-aza-1-azoniabicyclo[2.2.2]octane-κN4)copper(II) monohydrate

The asymmetric unit of the title compound, [CuCl3(C8H14N3)(H2O)]·H2O, comprises a neutral complex and a mol­ecule of free water. The complex contains coordinated CuII ions, with Cu—Cl distances ranging from 2.3471 (8) to 2.4011 (8) Å, and with Cu—N and Cu—O distances of 2.0775 (19) and 2.0048 (18) Å, respectively. The resulting coordination polyhedron is a trigonal bipyramid with the Cl atoms in the equatorial plane. In the crystal, O—H⋯Cl and O—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional structure.

Cu(en)2SiF6 and [Cu(dmen)2(H2O)]SiF6 (en = 1,2-diaminoethane; dmen = N,N-dimethyl-1,2-diaminoethane): Preparations, crystal structures, spectroscopic properties and hydrogen bonding mediated magnetism

Crystals of Cu(en)2SiF6 (en=1,2-diaminoethane) (1) and [Cu(dmen)2(H2O)]SiF6 (dmen=N,N-dimethyl-1,2-diaminoethane) (2) were isolated from aqueous–ethanolic systems Cu2+-en or dmen-SiF62−. The chain-like crystal structure of 1 is built up of [Cu(en)2]2+ complex cations linked by bridging μ2-SiF62− anions with trans positions of the bridging fluorine atoms. Copper ion exhibits usual distorted octahedral coordination; there are two chelate coordinated en ligands in the equatorial plane with CuN1 bonds of 1.9994(14)Å (4x), while the axial positions are occupied by fluorine atoms from SiF62− anions with CuF2 bond of 2.6065(14)Å (2x). The individual chains are linked by NH···F type hydrogen bonds. In 2 the coordination polyhedron of the Cu(II) atom can be described as slightly deformed square pyramid (τ=13.0%) with four N atoms from two chelate dmen ligands placed in the basal plane (CuN bonds are from the range 2.0164–2.0599Å) while the apical position is occupied by an aqua ligand at CuO distance is 2.293(2)Å. The structure of 2 is stabilized by OH···F and NH···F hydrogen bonds between complex cations and the hexafluoridosilicate anions. The EPR spectra show the rhombic anisotropy of g-factor in both complexes. Magnetic measurements indicate the presence of two-dimensional antiferromagnetic structure in both complexes. A weak exchange coupling J/kB=−0.85K was found in 1. Much stronger exchange coupling J/kB=−3.69K present in 2 allowed us to identify spatial anisotropy of the exchange coupling, α=0.2, and to describe 2 by rectangular antiferromagnetic lattice model.

Structural evolution of one-dimensional spin-ladder compounds Sr14−xCaxCu24O41with Ca doping and related evidence of hole redistribution

Incommensurate crystal structures of spin ladder series Sr14-xCaxCu24O41 (x=3, 7, 11, 12.2) were characterized by powder neutron scattering method and refined using the superspace group Xmmm(00{\gamma})ss0 (equivalent to superspace group Fmmm(0,0,1+{\gamma})ss0); X stands for non-standard centering (0,0,0,0), (0,1/2,1/2,1/2), (1/2,1/2,0,0), (1/2,0,1/2,1/2)) with a modulated structure model. The Ca doping effects on the lattice parameters, atomic displacement, Cu-O distances, Cu-O bond angles and Cu bond valence sum were characterized. The refined results show that the CuO4 planar units in both chain and ladder sublattices become closer to square shape with an increase of Ca doping. The Cu bond valence sum calculation provided new evidence for the charge transfer from the chains to ladders (approximately 0.16 holes per Cu from x=0 to 12.2). The charge transfer was attributed to two different mechanisms: (a) the Cu-O bond distance shrinkage on the ladder; (b) increase of the interaction between two sublattices, resulting in Cu-O bonding between the chains and ladders. The low temperature structural refinement resulted in the similar conclusion, with a slight charge backflow to the chains.

Bis(μ2-2-chlorobenzoato-κ2O:O′)bis[(2-chlorobenzoato-κO)(1,10-phenanthroline-κ2N:N′)copper(II)] dihydrate

In the title compound, [Cu2(C7H4ClO2)4(C12H8N2)2]·2H2O, the two crystallographically independent dinuclear complex mol­ecules, A and B, have different Cu⋯Cu separations, viz. 3.286 (1) Å in A and 3.451 (1) Å in B. Both independent mol­ecules reside on inversion centres, so the asymmetric unit contains a half-mol­ecule each of A and B and two water mol­ecules. Each Cu atom has a square-pyramidal environment, being coordinated by two O atoms from two bridging 2-chloro­benzoate ligands, one O atom from a monodentate 2-chloro­benzoate ligand and two N atoms from a 1,10-phenanthroline ligand. The water mol­ecules can also be considered as coordinating ligands, which complete the coordination geometry up to distorted octa­hedral with elongated Cu—O distances, viz. 3.024 (3) Å in A and 2.917 (3) Å in B. In the crystal, weak inter­molecular C—H⋯O inter­actions contribute to the consolidation of the crystal packing.

Bis(2-methylbenzoato-κ2O,O′)(1,10′-phenanthroline-κ2N,N′)copper(II)

In the title compound, [Cu(C8H7O2)2(C12H8N2)], the CuII atom assumes a distorted octa­hedral coordination geometry, chelated by two N atoms from the 1,10′-phenanthroline ligand and four O atoms from two 2-methyl­benzoate anions. A significant Jahn–Teller distortion is observed with two axial Cu—O distances significantly longer than those in the equatorial CuO2N2 plane. In the crystal, π–π stacking inter­actions, with centroid–centroid distances of 3.547 (3) or 3.728 (3) Å between the phenanthroline rings, form layers parallel to (011).

Bis(μ-naphthalene-1,8-dicarboxylato-κ2O1:O8)bis[aquabis(N,N′-dimethylformamide-κO)copper(II)

In the centrosymmetric dinuclear title complex, [Cu2(C12H6O4)2(C3H7NO)4(H2O)2], the coordination environment of each Cu(II) atom displays a distorted CuO5 square-pyramidal geometry, which is formed by two carboxyl­ate O atoms of two μ-1,8-nap ligands (1,8-nap is naphthalene-1,8-dicarboxyl­ate), two O atoms of two DMF (DMF is N,N′-dimethyl­formamide) and one coordinated water mol­ecule. The Cu—O distances involving the four O atoms in the square plane are in the range 1.9501 (11)–1.9677 (11) Å, with the Cu atom lying nearly in the plane [deviation = 0.0726 (2) Å]. The axial O atom occupies the peak position with a Cu—O distance of 2.885 (12) Å, which is significantly longer than the rest of the Cu—O distances. Each 1,8-nap ligand acts as bridge, linking two CuII atoms into a dinuclear structure. Inter­molecular O—H⋯O and C—H⋯O hydrogen-bonding inter­actions consolidate the structure.

A Trinuclear Cu(II) Complex from the Use of Phenyl 2-Pyridyl Ketoxime: Structure and Magnetic Behavior

The reaction of phenyl 2-pyridyl ketoxime (PhPyCNOH) with Cu(BF 4 ) 2 · 6H 2 O in methanol results in the trinuclear complex [Cu 3 (OH)(PhpyCNO) 3 (H 2 O)](BF 4 ) 2 (1), which has been characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction techniques. The structure of 1 exhibits a triangle of Cu(II) ions, centered by a triply bridging hydroxo ligand and with three edge-bridging oximate groups from the three PhPyCNO− ions. The Cu 3 OH units have an average Cu-O distance of 1.962(4) Å, an average Cu-Cu distance of 3.177(4) Å, and an average Cu-O-Cu angle of 108.2(2)°. Variable-temperature magnetic susceptibility studies reveal an antiferromagnetically-coupled system showing antisymmetric exchange.

Bis(μ-4-chloro-2-oxidobenzoato)bis[(1,10-phenanthroline)copper(II)] dihydrate

The structure of the the title compound, [Cu2(C7H3ClO3)2(C12H8N2)2]·2H2O, consists of a dimeric unit involving a planar Cu2O2 group arranged around an inversion center. The coordination sphere of the CuII atom can be described as an elongated distorted square pyramid where the basal plane is formed by the two N atoms of the 1,10-phenanthroline mol­ecule and the two O atoms of the hydroxy­chloro­benzoate (hcbe) anion. The long apical Cu—O distance of 2.569 (2) Å involves the O atom of a symmetry-related hcbe anion, building up the dinuclear unit. Each dinuclear unit is connected through O—H⋯O hydrogen bonds involving two water mol­ecules, resulting in an R 4 2(8) graph-set motif and building up an infinite chain parallel to (10). C—H⋯O inter­actions further stabilize the chain.