Synthesis,Characterization, DNA‐binding Properties,and ­Antioxidant Activity of a Copper(II) Complex with 1, 3‐Bis­(1‐allaylbenzimidazol‐2‐yl)‐2‐oxopropane

A new complex of copper(II) picrate (pic) with 1, 3‐bis(1‐allaylbenzimidazol‐2‐yl)‐2‐oxopropane (aobb), with the composition [Cu(aobb)₂](pic)₂, was synthesized and characterized. The crystal structure of the copper(II) complex revealed that the coordination environment around the central copper(II) atom is a distorted octahedral arrangement. Electronic absorption spectroscopy, ethidium bromide displacement experiments and viscosity measurements indicate that the ligand and the Cu^II complex can strongly bind to calf thymus DNA, presumably by an intercalation mechanism. Furthermore, the antioxidant activity of the Cu^II complex was determined by superoxide and hydroxyl radical scavenging method in vitro, which indicate that the Cu^II complex has the activity to suppress OH ^· and O₂ ^{· –}.     

Synthesis,Characterization, Crystal Structure,and Biological Activities of Transition Metal Complexes with 1‐Phenyl‐3‐methyl‐5‐hydroxypyrazole‐4‐methylene‐8′‐quinolineimine

The Schiff base ligand, 1‐phenyl‐3‐methyl‐5‐hydroxypyrazole‐4‐methylene‐8′‐quinolineimine, and its Cu^II, Zn^II, and Ni^II complexes were synthesized and characterized. The crystal structure of the Zn^II complex was determined by single‐crystal X‐ray diffraction, indicating that the metal ions and Schiff base ligand can form mononuclear six‐coordination complexes with 1:1 metal‐to‐ligand stoichiometry at the metal ions as centers. The binding mechanism and affinity of the ligand and its metal complexes to calf thymus DNA (CT DNA) were investigated by UV/Vis spectroscopy, fluorescence titration spectroscopy, EB displacement experiments, and viscosity measurements, indicating that the free ligand and its metal complexes can bind to DNA via an intercalation mode with the binding constants at the order of magnitude of 105–106 M ^–1, and the metal complexes can bind to DNA more strongly than the free ligand alone. In addition, antioxidant activities of the ligand and its metal complexes were investigated through scavenging effects for hydroxyl radical in vitro, indicating that the compounds show stronger antioxidant activities than some standard antioxidants, such as mannitol. The ligand and its metal complexes were subjected to cytotoxic tests, and experimental results indicated that the metal complexes show significant cytotoxic activity against lung cancer A 549 cells.     

Syntheses,Physico‐Chemical Studies and Antioxidant Activities of Transition Metal Complexes with a Perimidine Ligand

A series of mononuclear complexes of the type, [MLCl₂] [M = Co^II, Ni^II, Cu^II, and Zn^II] with a pyrimidene‐type ligand, which was synthesized by the reaction of 2‐furaldehyde and 1, 8‐diaminonaphthalene, was obtained. The ligand and its complexes were characterized by elemental analysis, IR, NMR, EPR, and UV/Vis spectroscopy, ESI‐mass spectrometry, magnetic susceptibility, molar conductivity, and thermogravimetric analyses. On the basis of UV/Vis spectroscopic and magnetic susceptibility data, an octahedral arrangement was assigned around all metal ions. The low molar conductivity data for all the complexes show their non‐electrolytic nature. The thermal behavior of the complexes was studied by TGA analyses. The electrochemical study carried out on the Cu^II complex exhibits a quasi reversible redox process. The ligand and its complexes showed potential antioxidant and antimicrobial activities.     

Synthese,Strukturen, NMR‐ und EPR‐Untersuchungen der binuklearen Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenoureato))‐Komplexe des NiII und CuII

Synthesis, Structures, NMR and EPR Investigations of Binuclear Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenoureato)) Complexes of Ni^II and Cu^II The synthesis of binuclear Cu^II and Ni^II complexes of the quadridentate ligand N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(selenourea) and their crystal structures are reported. The complexes crystallize monoclinic, P2₁/c (Z = 2). In the EPR spectra of the binuclear Cu^II complex exchange‐coupled Cu^II‐Cu^II pairs were observed. In addition the signals of a mononuclear Cu^II species are observed what will be explained with the assumption of an equilibrium between the binuclear Cu^II‐complex (Cu^II‐Cu^II pairs) and oligomeric complexes with “isolated” Cu^II ions. Detailed ¹³C and ⁷⁷Se NMR investigations on the ligand and the Ni^II complex allow an exact assignment of all signals of the heteroatoms.     

Copper(II) and Sodium(I) Complexes based on 3,7‐Diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide: Synthesis,Characterization, and Catalytic Activity

The reaction of 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane (DAPTA) with metal salts of Cu^II or Na^I/Ni^II under mild conditions led to the oxidized phosphane derivative 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide (DAPTA=O) and to the first examples of metal complexes based on the DAPTA=O ligand, that is, [Cu^II(μ‐CH₃COO)₂(κO‐DAPTA=O)]₂ ( 1 ) and [Na(1κOO′;2κO‐DAPTA=O)(MeOH)]₂(BPh₄)₂ ( 2 ). The catalytic activity of 1 was tested in the Henry reaction and for the aerobic 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO)‐mediated oxidation of benzyl alcohol. Compound 1 was also evaluated as a model system for the catechol oxidase enzyme by using 3,5‐di‐tert‐butylcatechol as the substrate. The kinetic data fitted the Michaelis–Menten equation and enabled the obtainment of a rate constant for the catalytic reaction; this rate constant is among the highest obtained for this substrate with the use of dinuclear Cu^II complexes. DFT calculations discarded a bridging mode binding type of the substrate and suggested a mixed‐valence Cu^II/Cu^I complex intermediate, in which the spin electron density is mostly concentrated at one of the Cu atoms and at the organic ligand.     

Synthesis,characterization, electrochemistry and kinetics of CTDNA binding of a bis ciprofloxacin borate copper(II) complex

A new boroderivative of ciprofloxacin and its Cu^II complex has been synthesized and characterized by elemental analysis, i.r., e.p.r., u.v.–vis., n.m.r. spectroscopy. Molar conductance measurements show that the complex is ionic. E.p.r. values and electronic spectral data suggest that it possesses square planar geometry. The reaction kinetics of the ligand K[C₃₄H₃₆N₆O₆F₂B] and its Cu^II complex with calf thymus DNA (CTDNA) has been monitored spectrophotometrically in aqueous media. The K _obs value has been calculated under pseudo-first order conditions and it has been observed that the Cu^II complex is a more efficient DNA inhibitor than the free borate of ciprofloxacin. The redox behavior of the Cu^II complex in the presence and in the absence of CTDNA in aqueous solution has been investigated by cyclic voltammetry. The cyclic voltammogram of the Cu^II complex exhibits one quasireversible redox wave for a one-electron transfer corresponding to Cu^II/Cu^I redox couple with E _1/2 values –0.613 and –0.649 V respectively. On interaction with CTDNA, the Cu^II complex exhibits a shift in E _1/2 values corresponding to 0.013 and 0.035 V respectively.     

Synthese,Struktur und EPR‐Untersuchungen von binuklearen Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(thioureato))‐Komplexen des CuII,NiII, ZnII,CdII und PdII

Synthesis, Structure and EPR Investigations of binuclear Bis(N,N,N?,N?‐tetraisobutyl‐N′,N″‐isophthaloylbis(thioureato)) Complexes of Cu^II, Ni^II, Zn^II, Cd^II and Pd^II The synthesis of binuclear Cu^II‐, Ni^II‐, Zn^II‐, Cd^II‐ and Pd^II‐complexes of the quadridentate ligand N,N,N?,N?‐tetraisobutyl‐N′,N″‐isophthaloylbis(thiourea) and the crystal structures of the Cu^II‐ and Ni^II‐complexes are reported. The Cu^II‐complex crystallizes in two polymorphic modifications: triclinic, (Z = 1) and monoclinic, P2₁/c (Z = 2). The Ni^II‐complex was found to be isostructural with the triclinic modification of the copper complex. The also prepared Pd^II‐, Zn^II‐ and Cd^II‐complexes could not be characterized by X‐ray analysis. However, EPR studies of diamagnetically diluted Cu^II/Pd^II‐ and Cu^II/Zn^II‐powders show axially‐symmetric g and A ^Cu tensors suggesting a nearly planar co‐ordination within the binuclear host complexes. Diamagnetically diluted Cu^II/Cd^II powder samples could not be prepared. In the EPR spectra of the pure binuclear Cu^II‐complex exchange‐coupled Cu^II‐Cu^II pairs were observed. According to the large Cu^II‐Cu^II distance of about 7,50Å a small fine structure parameter D = 26·10^?4 cm^?1 is observed; T‐dependent EPR measurements down to 5 K reveal small antiferromagnetic interactions for the Cu^II‐Cu^II dimer. Besides of the dimer in the EPR spectra the signals of a mononuclear Cu^II species are observed whose concentration is T‐dependent. This observation can be explained assuming an equilibrium between the binuclear Cu^II‐complex (Cu^II‐Cu^II pairs) and oligomeric complexes with “isolated” Cu^II ions.     

Poly[[aqua‐μ3‐2,2‐dimethylmalonato‐copper(II)] monohydrate] and poly[aqua‐μ3‐2,2‐dimethylmalonato‐copper(II)]

The coordination mode of the dimethylmalonate ligand in the two title Cu^II complexes, {[Cu(C₅H₃O₄)(H₂O)]·H₂O}_n, (I), and [Cu(C₅H₃O₄)(H₂O)]_n, (II), is the same, with chelated six‐membered, bis‐monodentate and bridging bonding modes. However, the coordination environment of the Cu^II atoms, the connectivity of their metal–organic frameworks and their hydrogen‐bonding interactions are different. Complex (I) has a perfect square‐pyramidal Cu^II environment with the aqua ligand in the apical position, and only one type of square grid consisting of Cu^II atoms linked via carboxylate bridges to three dimethylmalonate ligands, with weak hydrogen‐bond interactions within and between its two‐dimensional layers. Complex (II) has a coordination geometry that is closer to square pyramidal than trigonal bipyramidal for its Cu^II atoms with the aqua ligand now in the basal plane. Its two‐dimensional layer structure comprises two alternating grids, which involve two and four different dimethylmalonate anions, respectively. There are strong hydrogen bonds only within its layers.     

Synthesis,antimicrobial screening,and DNA-binding/cleavage of new pyrazole-based binuclear CoII,NiII, CuII,and ZnII complexes

Pyrazolato endogenous bridged binuclear Co^II, Ni^II, Cu^II, and Zn^II complexes were prepared and characterized by spectro-analytical methods. The hexadentate N₄S₂ donor was synthesized by condensation of 3,5-dichloroformyl-1H-pyrazole with thiosemicarbazide in dry ethanol. All the complexes were binuclear and octahedral in nature. The ligand and complexes are screened for antimicrobial and DNA-binding/cleavage activities. The binding/cleavage activities with Escherichia coli DNA are monitored with absorption, hydrodynamic, thermal denaturation, and electrophoresis studies. The ligand possesses significant activity against microbes which is further enhanced upon complexation. The DNA-binding study reveals classical intercalation. The Ni^II and Cu^II complexes exhibit higher binding ability.     

Synthese,Strukturen und X‐/Q‐Band‐EPR‐Untersuchungen von N,N‐Diethyl‐N′‐3,5‐di(trifluormethyl)benzoylthioureato‐Komplexen des CuII,NiII und PdII sowie EPR‐spektroskopische Charakterisierung eines CuII‐CuII‐Dimers

The synthesis and the structures of (i) the ligand N,N‐Diethyl‐N′‐3,5‐di(trifluoromethyl)benzoylthiourea HEt₂dtfmbtu and (ii) the Ni^II and Pd^II complexes of HEt₂dtfmbtu are reported. The ligand coordinates bidendate forming bis chelates. The Ni^II and the Pd^II complexes are isostructural. The also prepared Cu^II complex could not be characterized by X‐ray analysis. However, the preparation of diamagnetically diluted powders Cu/Ni(Et₂dtfmbtu)₂ and Cu/Pd(Et₂dtfmbtu)₂ suitable for EPR studies was successful. The EPR spectra of the Cu/Ni and Cu/Pd systems show noticeable differences for the symmetry of the CuS₂O₂ unit in both complexes: the Cu/Pd system is characterized by axially‐symmetric g< and A ^cu tensors; for the Cu/Ni system g and A ^Cu have rhombic symmetry. EPR studies on frozen solutions of the Cu^II complex show the presence of a Cu^II‐Cu^II dimer which is the first observed for Cu^II acylthioureato complexes up to now. The parameters of the fine structure tensor were used for the estimation of the Cu^II‐Cu^II distance.     

Protonation of a Biologically Relevant CuII μ‐Thiolate Complex: Ligand Dissociation or Formation of a Protonated CuI Disulfide Species?

The proton‐induced electron‐transfer reaction of a Cu^II μ‐thiolate complex to a Cu^I‐containing species has been investigated, both experimentally and computationally. The Cu^II μ‐thiolate complex [Cu^II₂( L^MeS )₂]²⁺ is isolated with the new pyridyl‐containing ligand L^MeSSL^Me , which can form both Cu^II thiolate and Cu^I disulfide complexes, depending on the solvent. Both the Cu^II and the Cu^I complexes show reactivity upon addition of protons. The multivalent tetranuclear complex [Cu^I₂Cu^II₂( LS )₂(CH₃CN)₆]⁴⁺ crystallizes after addition of two equivalents of strong acid to a solution containing the μ‐thiolate complex [Cu^II₂( LS )₂]²⁺ and is further analyzed in solution. This study shows that, upon addition of protons to the Cu^II thiolate compound, the ligand dissociates from the copper centers, in contrast to an earlier report describing redox isomerization to a Cu^I disulfide species that is protonated at the pyridyl moieties. Computational studies of the protonated Cu^II μ‐thiolate and Cu^I disulfide species with LSSL show that already upon addition of two equivalents of protons, ligand dissociation forming [Cu^I(CH₃CN)₄]⁺ and protonated ligand is energetically favored over conversion to a protonated Cu^I disulfide complex.     

A new stepped tetranuclear copper(II) complex: synthesis,crystal structure and photoluminescence properties

Binuclear and tetranuclear copper(II) complexes are of interest because of their structural, magnetic and photoluminescence properties. Of the several important configurations of tetranuclear copper(II) complexes, there are limited reports on the crystal structures and solid‐state photoluminescence properties of `stepped' tetranuclear copper(II) complexes. A new Cu^II complex, namely bis{μ₃‐3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolato}bis{μ₂‐3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolato}tetracopper(II), [Cu₄(C₁₁H₁₃NO₃)₄], has been synthesized and characterized using elemental analysis, FT–IR, solid‐state UV–Vis spectroscopy and single‐crystal X‐ray diffraction. The crystal structure determination shows that the complex is a stepped tetranuclear structure consisting of two dinuclear [Cu₂(L )₂] units {L is 3‐[(4‐methoxy‐2‐oxidobenzylidene)amino]propanolate}. The two terminal Cu^II atoms are four‐coordinated in square‐planar environments, while the two central Cu^II atoms are five‐coordinated in square‐pyramidal environments. The solid‐state photoluminescence properties of both the complex and 3‐[(2‐hydroxy‐4‐methoxybenzylidene)amino]propanol (H₂L ) have been investigated at room temperature in the visible region. When the complex and H₂L are excited under UV light at 349 nm, the complex displays a strong blue emission at 469 nm and H₂L displays a green emission at 515 nm.     

Disentangling steric and electronic factors in monomeric bis(2‐bromo‐4‐chloro‐6‐{[(2‐hydroxyethyl)imino]methyl}phenolato‐κ2N,O)copper(II)

The title compound, [Cu(C₉H₈BrClNO₂)₂], is a square‐planar complex. The potentially tridentate dibasic 2‐bromo‐4‐chloro‐6‐{[(2‐hydroxyethyl)imino]methyl}phenolate ligand coordinates in a trans‐bis fashion to the Cu^II centre via the imine N and phenolate O atoms. The Cu^II atom lies on the centre of inversion of the molecule. The potentially coordinating hydroxyethyl group remains protonated and uncoordinated, taking part in intermolecular hydrogen bonds with vicinal groups, leading to the formation of a two‐dimensional hydrogen‐bond network with sheets parallel to the (10) plane. Substituent effects on the crystal packing and coordination modes of the ligand are discussed.     

Di‐μ‐chlorido‐bis({2‐[1‐(2‐pyridylethylimino)ethyl]pyrrolato‐κ3N,N′,N′′}copper(II))

The title compound, [Cu₂(C₁₃H₁₄N₃)₂Cl₂], is a neutral dimeric copper(II) complex. The two Cu^II atoms are asymmetrically bridged by two chloride ions. Each Cu^II atom is also bound to the three N atoms of a deprotonated tridentate Schiff base ligand, giving a distorted square‐pyramidal N₃Cl₂ coordination environment overall. The dinuclear complex lies across an inversion centre in the space group P. This work demonstrates the effect of ligand flexibility and steric constraints on the structures of copper(II) complexes.     

Cyano‐bridged Molecular Square: [Ni(iprtacn)Fe(phen)2(CN)2]2(PF6)4·6CH3CN – Preparation,Structure, Magnetic Properties and Binding with DNA

The cyano‐bridged molecular square Ni(iprtacn)]₂[Fe(phen)₂(CN)₂]₂(PF₆)₄ · 6CH₃CN ( 1 ) (iprtacn = 1,4,7‐triisopropyl‐1,4,7‐triazacyclononane, phen = 1, 10‐phenanthroline) was prepared and its crystal structure, magnetic properties, and binding with DNA were characterized. The four metal ions Ni^IIFe^IINi^IIFe^II of the complex 1 are almost coplanar. Magnetic susceptibilities measured over the range of 2–300 K show weak antiferromagnetic interactions between the two nickel(II) ions; best fitting for the experimental data leads to J = –1.27 cm^–1. UV/Vis and fluorescence spectra show that the complex is able to displace DNA‐bound EB and bind to DNA with strong interactions.     

Nickel(II), Cadmium(II), and Copper(II) Complexes Based on Ditopic Terpyridine Derivative Ligand: Syntheses,Crystal Structures,and Luminescent Properties

Three complexes with the ditopic ligand 4′‐[4‐(quinolin‐8‐yloxymethyl)phenyl]‐2,2′:6′,2′′‐terpyridine (abbreviated as L ), [Ni(L)₂](CH₃COO)₂ ( 1 ), [Cd(L)₂](ClO₄)₂ ( 2 ), and [Cu₂(L)₂](ClO₄)₄ · 4DMF ( 3 ), were synthesized and characterized by elemental analysis, IR spectroscopy, and structurally analyzed by X‐ray single‐crystal diffraction. Interestingly, in complexes 1 and 2 , two ligands adopt a tridentate chelating pattern where the oxaquinoline group is non‐coordinated and coordinate with one M^II ion (M = Ni for 1 , M = Cd for 2 ) to form a mononuclear unit. In complex 3 , two ligands bridge two Cu^II ions by pyridyl N atoms, ethereal O atoms, and quinolyl N atoms in a head‐to‐tail mode to generate a dinuclear [Cu₂L₂] unit. Moreover, extended 1D and 2D supramolecular architectures are further constructed in 1 – 3 by multiple secondary interactions such as aromatic stacking and hydrogen bonding. Notably, the structural diversity of complexes 1 – 3 can be properly assigned to the central metal ions that have distinct coordination preferences. In addition, luminescent properties of the ligand and complex 2 were also investigated.     

Metal(II) Ion Complexes with 5‐(Pyrazin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione; Synthesis,Structural Characterization,Acid‐base,and Complexing Properties in Solution

The study reports the synthesis of complexes Co(HL)Cl₂ ( 1 ), Ni(HL)Cl₂ ( 2 ), Cu(HL)Cl₂ ( 3 ), and Zn(HL)₃Cl₂ ( 4 ) with the title ligand, 5‐(pyrazin‐2‐yl)‐1,2,4‐triazole‐5‐thione (HL), and their characterization by elemental analyses, ESI‐MS (m/z), FT‐IR and UV/Vis spectroscopy, as well as EPR in the case of the Cu^II complex. The comparative analysis of IR spectra of the metal ion complexes with HL and HL alone indicated that the metal ions in 1 , 2 , and 3 are chelated by two nitrogen atoms, N(4) of pyrazine and N(5) of triazole in the thiol tautomeric form, whereas the Zn^II ion in 4 is coordinated by the non‐protonated N(2) nitrogen atom of triazole in the thione form. pH potentiometry and UV/Vis spectroscopy were used to examine Co^II, Ni^II, and Zn^II complexes in 10/90 (v/v) DMSO/water solution, whereas the Cu^II complex was examined in 40/60 (v/v) DMSO/water solution. Monodeprotonation of the thione triazole in solution enables the formation of the L:M = 1:1 species with Co^II, Ni^II and Zn^II, the 2:1 species with Co^II and Zn^II, and the 3:1 species with Zn^II. A distorted tetrahedral arrangement of the Cu^II complex was suggested on the basis of EPR and Vis/NIR spectra.     

A new oxamato-bridged heterotrinuclear NiIICuIINiII complex: synthesis,structure and properties

A new oxamato-bridged Ni^IICu^IINi^II species, [Ni(iprtacn)]₂[Cu(pba)(H₂O)_0.5](BPh₄)₂ (1), (iprtacn?=?1,4,7-triisopropyl-1,4,7-triazacyclononane; pba?=?1,3-propylenebis(oxamato)) has been synthesized and structurally as well as magnetically characterized. Complex 1 has a discrete trinuclear Ni^IICu^IINi^II structure: Two nickel(II) ions are bridged by [Cu(pba)]^2? with the macrocyclic ligand iprtacn a terminal ligand of nickel(II). Fitting the magnetic data of 1 led to g _Cu?=?2.16, g _Ni?=?2.18, J?=??112.5?cm^?1, D?=?±7.78?cm^?1. The irregular spin state structure and interaction of complex 1with DNA are described here.     

Synthesis,Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)2(H2O)].NaNO3

Transition metal complexes of arginine (using Co(II), Ni(II), Cu(II) and Zn(II) cations separately) were synthesized and characterized by FTIR, TG/DTA‐DrTG, UV‐Vis spectroscopy and elemental analysis methods. Cu(II)‐Arg complex crystals was found suitable for x‐ray diffraction studies. It was contained, one mole Cu^II and Na⁺ ions, two arginate ligands, one coordinated aqua ligand and one solvent NO₃^? group in the asymmetric unit. The principle coordination sites of metal atom have been occupied by two N atoms of arginate ligands, two carboxylate O atoms, while the apical site was occupied by one O atom for Cu^II cation and two O atoms for Co^II, Ni^II, Zn^II atoms of aqua ligands. Although Cu^II ion adopts a square pyramidal geometry of the structure. Co^II, Ni^II, Zn^II cations have octahedral due to coordination number of these metals. Neighbouring chains were linked together to form a three‐dimensional network via hydrogen‐bonding between coordinated water molecule, amino atoms and O atoms of the bridging carboxylate groups. Cu^II complex was crystallized in the monoclinic space group P2₁, a = 8.4407(5) Å, b = 12.0976(5) Å, c = 10.2448(6) Å, V = 1041.03(10) ų, Z = 2. Structures of the other metal complexes were similar to CuII complex, because of their spectroscopic studies have in agreement with each other. Copper complex has shown DNA like helix chain structure. Lastly, anti‐bacterial, anti‐microbial and anti‐fungal biological activities of complexes were investigated.     

A square‐pyramidal copper(II) complex with strong intramolecular hydrogen bonds: diaqua(N,N′‐dimethylformamide‐κO)bis[2‐(diphenylphosphoryl)benzoato‐κO]copper(II)

In the title Cu^II complex, [Cu(C₁₉H₁₄O₃P)₂(C₃H₇NO)(H₂O)₂], the molecule is bisected by a twofold axis relating the two 2‐(diphenylphosphoryl)benzoate (ODPPB) ligands. The asymmetric unit consists of a Cu^II metal centre on the symmetry axis, an ODPPB ligand, one water ligand and one dimethylformamide (DMF) ligand (disordered around the twofold axis). The Cu^II ion has fivefold coordination provided by two carboxylate O atoms from two ODPPB ligands, two O atoms from two coordinated water molecules and another O atom from a (disordered) DMF molecule, giving a CuO₅ square‐pyramidal coordination geometry. The ODPPB ligand adopts a terminal monocoordinated mode with two free O atoms forming two strong intramolecular hydrogen bonds with the coordinated water molecules, which may play a key role in the stability of the molecular structure, as shown by the higher release temperature for the coordinated water molecules than for the coordinated DMF molecule. The optical absorption properties of powder samples of the title compound have also been studied.