Synthesis and structural characterization of copper(II) complexes with a tetradentate semicarbazone ligand derived from 2,5-hexadione

Four Cu(II) complexes [CuLH2O](ClO4)2, 1; [CuLCl]Cl.H2O, 2; [CuLBr]2(Cu3Br5), 3; and [CuLH2O](NO3)2, 4; where L=tetradentate semicarbazone ligand, have been synthesized and characterized by elemental analysis, FT-IR and UV–Vis. The structures of compounds 1 and 3 have been determined by single-crystal X-ray difraction analyses. In mononuclear 1, the semicarbazone, L acts as a tetradentate neutral ligand and a water molecule also coordinates to the Cu atom. There are two independent [CuL(H2O)]2+ cations and four perchlorate anions in the crystallographic asymmetric unit. One of the cations has a weak interaction between its Cu atom and a O atom of an adjacent perchlorate anion. The structure of 3 contains two independent [CuLBr]+ cations and a (Cu3Br5) 2− anion. The coordination geometry around the cation’s Cu(II) ion is fve-coordinated square pyramidal, with L acting as a tetradentate neutral ligand and with a Br at the apical position. The Cu3Br5 2− anions link to one another to form an infnite one-dimensional (Cu3Br5 2−)n chain. Furthermore, the Hirshfeld surface analyses and the 2D fngerprint plot have been discussed.The authors are grateful to the Yazd University and the Australian National University for partial support of this wor

Synthesis, structure characterization, DNA binding, and cleavage properties of mononuclear and tetranuclear cluster of copper(II) complexes

Two copper(II) complexes, cluster 1, and mononuclear 2, have been synthesized by reacting acetylacetone and benzohydrazide (1:1 ratio for 1 and 1:2 ratio for 2) with CuCl2 in a methanol solution. In 2, which is a new complex, the ligand acts as a tetradentate which binds the metal ion via two amide-O atoms and two imine-N atoms providing an N2O2 squa-re-planar around the copper(II) ion. The absorption spectra data evidence strongly suggested that the two copper(II) compounds could interact with CT-DNA (intrinsic binding constant, Kb = 0.45 × 10⁴ M⁻¹ for 1 and Kb = 2.39 × 10⁴ M⁻¹ for 2). The super coiled plasmid pBR322 DNA cleavage ability was studied with 1 and 2 in the presence and absence of H₂O₂ as an oxidant. In both the absence and the presence of an oxidizing agent, complex 2 exhibited no nuclease activity. However, even in the absence of an oxidant, complex 1 exhibited significant DNA cleavage activity.The authors are grateful to the Yazd University and the Australian National University for partial support of this work

Synthesis and Structural Characterization of a Double Helical Dinuclear Copper(II) Complex With Tetradentate Biacetyl Bis(benzoylhydrazone)

The reaction of tetradentate hydrazone ligand H2babh with Cu(CH3COO)2 in methanol solvent leads to the formation of the mono-nuclear complex [Cu(babh)]. However, on being dissolved in dichloromethane solvent and on addition of ethanol solvent, a dinuclear complex of [Cu2(μ1,3-babh)2(C2H5OH)2] is obtained. The X-ray crystallography indicates that the dinuclear helical complex formation is caused due to the unsymmetrical twisting of the H2babh ligand. One oxygen and two nitrogen atoms from the ligand and one oxygen atom from the other ligand coordinate to each copper(II) center. Both the copper(II) centers in a dinuclear unit are penta-coordinate with a slightly distorted square pyramidal geometry. The IR spectra of mono- and dinuclear copper(II) complexes have different bands. The absorption spectra of mono- and di-nuclear complexes are quite similar in methanol solvent. However, the electronic absorption spectra of the two complexes are basically different in the solid state.The authors are grateful to the Yazd University (YU) and the Australian National University (ANU) for partial support of this work

Nickel(II) Complex with a Flexidentate Ligand Derived from Acetohydrazide: Synthesis, Structural Characterization and Hirshfeld Surface Analysis

The mononuclear Ni(II) complex [Ni(Lp)2(CH3OH)2]Cl2 has been synthesized by reacting 1-(5-hydroxy-3-methyl-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl)ethan-1-one ligand (HL) with NiCl2.6H2O in methanol solution. In the reaction, the tridentate ligand, HL, was converted in situ into 4-hydroxy-4-phenylbut-3-en-2-ylidene)acetohydrazid ligand, (pyrazole, Lp). The pyrazole ligand acts as bidentate neutral ligand and the hydroxyl group is left uncoordinated. The structure of the Ni(II) complex has been established by X-ray crystallography. The Ni(II) is six-coordinate and has a distorted octahedral geometry. It is bonded by two nitrogen and by two oxygen atoms of the two pyrazole ligands and two oxygen atoms of methanol molecules. The Hirshfeld surface analysis and the 2D the fingerprint plot are used to analyses all of the intermolecular contacts in the crystal structures. The main intermolecular contacts are H/H and Cl/H interactions

Synthesis, X-ray structural characterization, and DFT calculations of binuclear mixed-ligand copper(II) complexes containing diamine, acetate and methacrylate ligands

The dinuclear Cu(II) complexes [Cu(en)(MAA)(µ-CH3COO)]2 (1) and [Cu(pn)(MAA)(µ-CH3COO)]2 (2) where MAA, en and pn are methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental analysis, FT-IR and UV-Vis spectroscopy. The structures of the complexes have been determined by single-crystal X-ray diffraction analyses. In the dinuclear complexes 1 and 2 the two copper centers are five-coordinated and exhibit distorted square pyramidal geometries. The theoretical geometries of the studied compounds have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level considering effective core potential (ECP)

Synthesis, X-ray Structural Characterization, and DFT Calculations of Mononuclear Nickel(II) Complexes Containing Diamine and Methacrylate Ligands

The mononuclear Ni(II) complexes [Ni(en)2(H2O)2](MAA)2 (1) and [Ni(pn)2(MAA)2] (2), where MAA, en and pn are methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental analysis, FT-IR and UV–Vis spectroskopy. Structures of the complexes have been determined by single-crystal X-ray diffraction analyses. In the nickel(II) complexes 1 and 2 nickel(II) ion is six-coordinate and has a distorted octahedral geometry. Ni(II) is bonded to four nitrogen atoms of the two diamines and additionally to two oxygen atoms of aqua ligand in 1, and two oxygen atoms of methacrylate ligands in 2. The theoretical geometries of the studied compounds have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level and considering effective core potential (ECP). The comparison of the results indicates that the employed DFT method yields good agreement with experimental data

Tetra(μ3-hydroxo) bridged copper(II) tetranuclear cubane complexes: synthesis, crystal structure, and DNA binding studies

The tridentate Schiff base H2L was synthesized by the condensation of equimolar amount of 1-amino-2-propanol and salicylaldehyde. The reaction of H2L with an equimolar amount of Cu(CH3COO)2·H2O in methanol leads to the formation of the tetranuclear Cu4L4, 1. However, reaction of equimolar amount of H2L, copper(II) acetate, and 2,4,6-trimethylaniline in methanol forms a mixture of products which includes a discrete mononuclear complex Cu(L′)2, 2m (where HL′ is a bidentate ligand), in addition to the tetranuclear Cu4L4 species, 2c. In both tetranuclear cubane species, the tridentate H2L is both a chelating and a bridging ligand, after deprotonation of the enolic and the phenolic OH. The copper(II) centers are five-coordinate with a [N, O4] donor set from the ligands. The coordination geometry about each copper is distorted square pyramidal with one nitrogen and two oxygen from one ligand and two oxygen from adjacent ligands in the next unit of the cubane. In mononuclear 2m, the ligand is bidentate and the coordination geometry around copper(II) is square planar. The absorption spectra strongly suggest that tetranuclear 1 interacts with CT-DNA

Anion and solvent effects on the coordination behavior of N-(2-pyridinylmethylene)benzoylhydrazone with copper(II): Synthesis and structural characterization

The Cu(II) complexes [Cu(HL)Cl2], 1; [Cu(HL)(NO3)(H2O)]NO3, 2a; [Cu(L)(NO3)]2·C3H8O, 2b; [Cu(L)(μ1,1-N3)]2, 3; [Cu(L)(Br)]2, 4; [(H2O)CuL(-SO4)CuL], 5a; [CuL(-SO4)CuL]·H2O, 5b and [Cu(L)(CH3COO)]2, 6, where HL is a benzoylhydrazone tridentate Schiff base, have been synthesized and characterized by elemental analysis, FTIR, and UV-vis. The structures of 2a, 2b, 3, 4, 5a, and 5b have been determined by single-crystal X-ray diffraction analyses. In 2a, the benzoylhydrazone ligand is neutral and coordinates in its keto form and copper(II) has a distorted octahedral geometry. In dinuclear 2b, 3, 4, 5a, and 5b, there are bridging counter anions and the benzoylhydrazone ligand is monoanionic, coordinating in its enol form. In 5a and 5b, the enolic ligand also supplies a bridging alkoxo to the adjacent copper ion. In 5a, one of the two copper ions is five-coordinate in a distorted square pyramidal geometry, while the other copper ion has an additional water bonded to it in a distorted octahedral geometry. In 5b, both copper ions are five-coordinate with distorted square pyramidal geometries

Synthesis, crystal structure and electronic properties of bis(N-2-bromophenyl-salicydenaminato)copper(II) complex

A new series of complexes of the type bis(N-substituted-salicydenaminato)copper(II) (1-9), have been synthesized and characterized by IR, UV-Vis and elemental analysis methods. The molecular structure of bis(N-2-bromophenyl-salicydenaminato)copper(II) (6), was determined using X-ray crystallography. There are two independent molecules in the structure. Each shows a neutral, mononuclear, four-coordinate, square-planar trans-Cu[N2O2] geometry and, in each, the Cu atom and the ligating atoms are coplanar. The chelating N-Cu-O angle is 91.39(11)° for molecule one and 91.20(11)° for molecule two, whereas the non-chelating N-Cu-O angles are 88.61(11) and 88.80(11)°, respectively. The trans-N-Cu-N and trans-O-Cu-O bond angles are 180°. The electronic absorption spectra of copper(II) complexes (1-9), indicate that the d-d band energy is dependent on the nature and position of substituent on phenyl ring of the salicyldenimine ligand. The UV-Vis spectra in various solvents were measured and a relationship between absorption spectra and dielectric constant of the solvents is reported

Synthesis and crystal structure of a new hetro-nuclear Cu 2 Sr complex of salen type ligand

A new hetero-trinuclear complex [Cu2(μ-L) 2Sr(NO3)2] has been synthesized and characterized by elemental analysis, IR, UV-Vis and X-ray crystallography, where L is a dianionic tetradentate Schiff base ligand with N2O 2 donor atoms. The X-ray structure i