Synthesis,characterization and crystal structures of a pair of azido-bridged polynuclear Schiff base copper(II) complexes with urease inhibitory activity

A pair of azido-bridged Schiff base copper complexes, [CuL1(μ_1,3-N₃)] _n · nClO₄ (1) and [Cu₂(L2)₂(μ _1,1-N₃)₂] · 2ClO₄ (2) (L1 = N,N-diethyl-N′-(1-pyridin-2-ylmethylidene)ethane-1,2-diamine, L2 = N-isopropyl-N′-(1-pyridin-2-ylmethylidene)ethane-1,2-diamine) have been obtained by the same synthetic procedures, but with slightly different Schiff bases. The structures of the complexes have been characterized by IR spectra, elemental analysis, and single crystal X-ray determination. Each Cu atom in the complexes is five-coordinate in a square pyramidal configuration involving the three N atoms of the Schiff base ligand and two N atoms from two bridging azide ligands. The azide ligands adopt end-to-end bridging mode in (1), and end-on bridging mode in (2). The different coordination modes of the azide ligands in the two complexes are assigned to the steric effects of the terminal groups (two ethyl groups for (1) and one isopropyl group for (2)) in the Schiff base ligands. The urease inhibitory activities of the complexes were evaluated. Both of them showed potent inhibition against jack bean urease. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,crystal structures and xanthine oxidase inhibitory activities of two copper(II) complexes with Schiff bases

Two azido-coordinated Schiff base Cu(II) complexes with the formulae [Cu(L1)(N₃)]·MeOH and [Cu(L2)(μ_1,1-N₃)] _n , where L1 is the deprotonated form of 2-chloro-2-[(2-ethylaminoethylimino)methyl]phenol, and L2 is the deprotonated form of 2,4-dibromo-6-[(2-dimethylaminoethylimino)methyl]phenol, have been synthesized and characterized by physico-chemical and spectroscopic methods. The X-ray crystal structures of both complexes have been determined. The Cu atom in [Cu(L1)(N₃)]·MeOH is four-coordinate in a square planar geometry, while [Cu(L2)(μ_1,1-N₃)] _n is five-coordinate with a square pyramidal geometry. The molecules in [Cu(L1)(N₃)]·MeOH are linked by intermolecular O–H···O and N–H···O hydrogen bonds, forming dimers. The molecules in [Cu(L2)(μ_1,1-N₃)] _n are linked through end-on azido bridges, forming one-dimensional chains. The xanthine oxidase inhibitory activities of both complexes were evaluated.     

Syntheses,crystal structures and antibacterial activities of azido-bridged cobalt(III) complexes with Schiff bases

Two end-on azido-bridged Co(III) complexes, [Co₃(L1)₂(μ_1,1-N₃)₄(N₃)₂(OH₂)(OCH₂CH₃)]·0.5H₂O (1) and [Co₂(L2)₂(μ_1,1-N₃)₂(N₃)₂] (2), where L1 and L2 are the deprotonated form of 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenol and 2-ethoxy-6-[(2-isopropylaminoethylimino)methyl]phenol, respectively, were prepared and structurally characterized by physicochemical and spectroscopic methods and single crystal X-ray determination. Complex (1) is a trinuclear Co compound, while complex (2) is a centrosymmetric dinuclear Co compound. In both complexes, the Co atoms are in octahedral coordination. The preliminary biological tests show that the complexes have excellent antibacterial activity.     

Anion‐controlled Syntheses and Crystal Structures of a Pair of Novel Azide‐bridged Copper(II) Complexes Constructed from 4‐Chloro‐2‐[(2‐dimethylaminoethylimino)methyl]phenol

A pair of novel azide‐bridged polynuclear copper(II) complexes, [CuL(μ_1,1‐N₃)]_n ( 1 ) and [Cu₄L₂(CH₃COO)₂(μ_1,1‐N₃)₄] ( 2 ) (L = 4‐chloro‐2‐[(2‐dimethylaminoethylimino)methyl]phenolate), have been obtained from the same Schiff base ligand and an identical synthetic procedure using anions of the metal salts as the only independent variable. Complex 1 was synthesized using copper(II) nitrate, while complex 2 was synthesized using the copper(II) acetate as the salt. Both of the complexes show novel supramolecular structures in their crystals as elucidated by X‐ray analyses. The polynuclear complex 1 contains [CuL(μ_1,1‐N₃)]_n units as the building blocks, crystallizes in the Pbca space group. The tetra‐nuclear complex 2 contains [Cu₄L₂(CH₃COO)₂(μ_1,1‐N₃)₄] units as the building blocks, crystallizes in the space group.     

Synthesis,X-ray crystal structure,and electrochemistry of polynuclear azido-bridged manganese(III) and copper(II) Schiff base complexes

New azido-bridged [Mn^III(salabza)(μ-1,3-N₃)]_n (1), and [Cu^II₄(salabza)₂(μ-1,1-N₃)₂(N₃)₂(HOCH₃)₂],(2) complexes with an unsymmetrical Schiff base ligand, {H₂salabza = N,N’-bis(salicylidene)-2-aminobenzylamine}, have been synthesized, characterized by spectroscopic and electrochemical methods, and their crystal structures have been determined by X-ray diffraction. In complex 1, each manganese(III) atom is coordinated with N₂O₂ donor atoms from salabza and two adjacent Mn(III) centers are linked by an end-to-end (EE) azide bridge to form a helical polymeric chain with octahedral geometry around the Mn(III) centers. Complex 2 is a centrosymmetric tetranuclear compound containing two types of Cu(II) centers with square pyramidal geometry. Each terminal copper atom is surrounded by N₂O₂ atoms of a salabza ligand, and the oxygen atom of the methanol molecule. Each central copper(II) ion is coordinated with two phenoxo oxygen atoms from one salabza, one terminal azido, and two end-on (EO) bridging azido ligands. The central copper(II) ions are linked to each other by the two end-on (EO) azido groups.     

Synthesis, crystal structures, and urease inhibitory activities of two azido-bridged polynuclear copper(II) complexes with Schiff bases

Two azido-bridged polynuclear Cu(II) complexes with the formulae [Cu(L1)(μ_1,3-N₃)] _n and [Cu(L2)(μ_1,3-N₃)] _n (HL1 = 2-[(2-morpholin-4-ylethylimino)methyl]phenol, HL2 = 2-methoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol), have been synthesized and characterized by physico-chemical and spectroscopic methods. The Cu atom in each of the complexes is five-coordinate in a square pyramidal geometry, with one O and two N atoms of a Schiff base ligand and one terminal N atom of a bridging azido ligand defining the base-plane, and with another terminal N atom of a symmetry-related azido ligand occupying the apical position. The molecules are linked through end-to-end azido bridges, forming one-dimensional polymeric chains. Both of the complexes show moderate inhibitory activities against jack bean urease.     

Synthesis,crystal structure,and magnetic properties of 1D Azido-bridged copper(II) complex

A novel copper(II)-azide complex of [Cu₂(DMAP)₂(μ-1,1-N₃)₂(μ-1,3-N₃)₂]_n (DMAP = 4-(dimethylamino)pyridine) has been synthesized and characterized by IR spectra, X-ray diffraction, elemental analysis, and magnetism measurement. The complex reveals a 1D ladder-like chain structure, in which two μ-1,1-N₃ and two μ-1,3-N₃ bridges form a dimeric unit of [Cu₂(DMAP)₂(μ-1,1-N₃)₂(μ-1,3-N₃)₂] and are then connected to each other from the tail nitrogens of two asymmetric μ-1,3-N₃ bridges to generate a chain structure that stacks in the cell to construct the 3D crystal. The Cu atom is five-coordinated by azide anions to form a distorted square-pyramid of CuN₅ (τ = 0.2667). Magnetic susceptibility of complex exhibits a ferromagnetic interaction between the copper(II) ions through two kinds of azido-bridges. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,Characterization, Crystal Structures,and Antibacterial Activity of Polynuclear Nickel(II) and Copper(II) Complexes with Similar Tridentate Schiff Bases

An end-on azido-bridged dinuclear nickel(II) complex [Ni₂(L¹)₂(μ_1,1-N₃)₂] · CH₃COOH (I) and an end-on azido-bridged polynuclear copper(II) complex [CuL²(μ_1,1-N₃)] _n , where L¹ is the deprotonated form of 2-[(2-ethylaminoethylimino)methyl]-4-fluorophenol and L2 is the deprotonated form of 2-[(2- dimethylaminoethylimino)methyl]-4-fluorophenol, were prepared and characterized by elemental analysis and FT-IR spectra. Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method (CIF files CCDC nos. 942641 (I) and 942642 (II)). Single crystal X-ray structural studies indicate that the Schiff base ligands coordinate to the metal atoms through phenolate oxygen, imine nitrogen, and amine nitrogen. The Ni atoms in the nickel complex are in octahedral coordination, and the Cu atoms in the copper complex are in square pyramidal coordination. Crystals of the complexes are stabilized by hydrogen bonds. The Schiff bases and the complexes showed potent antibacterial activities.     

Syntheses and crystal structures of two tetranuclear copper(II) complexes with Schiff bases

Two similar tetranuclear copper(II) complexes with the formulae [Cu₄(L1)₂(μ_1,1-N₃)₄(μ₂-CH₃COO)₂] and [Cu₄(L2)₂(μ_1,1-N₃)₂(μ-Br)₂Br₂(CH₃OH)₂], where L1 and L2 are the deprotonated forms of 2-[(2-ethylaminoethylimino)methyl]-5-methoxyphenol and 5-methoxy-2-[(2-piperidin-1-ylethylimino)methyl]phenol, respectively, have been synthesized and characterized by spectroscopic methods and single-crystal X-ray diffraction. Both complexes are centrosymmetric tetranuclear copper(II) compounds. The bridging groups in [Cu₄(L1)₂(μ_1,1-N₃)₄(μ₂-CH₃COO)₂] are μ_1,1-azide ligands and μ₂-acetate ligands, and those in [Cu₄(L2)₂(μ_1,1-N₃)₂(μ-Br)₂Br₂(CH₃OH)₂] are μ_1,1-azide ligands and μ-bromide ligands. Each Cu atom in the complexes is in a square pyramidal geometry.     

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)₂(SCN)] · ClO₄ (1) and a tetranuclear cobalt(II) complex [Co₄(L)₄(N₃)₄](OH)₄ · 2H₂O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN⁻ in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular π...π stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in μ-1,1-N₃ (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.     

Single end-on azido bridged 1D chain copper(II) complex: Synthesis,X-ray crystal structure and catalytic activity in homogeneous epoxidation of cyclooctene

A new azido derivative of a NNO donor tridentate Schiff-base copper(II) complex, [CuL(μ_1,1-N₃)]_n (1) (HL = 1-(N-ortho-hydroxyacetophenimine)-2-(N-ethyl)aminoethane), containing a single end-on μ_1,1-azido bridged 1D infinite chain has been synthesized and characterized. X-ray single crystal structure analysis reveals that the complex [CuL(μ_1,1-N₃)]_n (1) is a 1D chain in which neighboring Cu(II) chromophores are related by glide planes and linked by single azido bridges in the EO mode. No measurable magnetic interaction was evidenced in the complex [CuL(μ_1,1-N₃)]_n (1) through variable temperature magnetic susceptibility measurements (10–300 K). The complex was used as an active catalyst for the epoxidation of cyclooctene using tert-butyl-hydroperoxide as an oxidant. The catalytic activity of the complex has been compared in a series of solvents. The results show that in acetonitrile medium, the epoxide was produced in high yield with high selectivity.     

A novel azide copper complex: [[Azido{bis[2-(piperidin-1-ylmethyl)pyridine]}copper(II)]perchlorate] hydrate

Synthesis and single crystal X-ray diffraction study were carried for compound {[Cu(C₁₁H₁₆N₄)₂(N₃)](ClO₄)} · H₂O (I). The structure is molecular, and the Cu²⁺ ion is in a five-coordinated compressed trigonal bipyramid environment. Copper ion is bound to five N atoms, in which four N atoms are from two chlelating ligands 2-(piperidin-1-ylmethyl)pyridine and the fifth N donor is from a monodentate azido ligand. The complex cations [Cu(C₁₁H₁₆N₄)₂(N₃)]⁺, the perchlorate anions, and solvent water molecules are further joined into three dimensional supramolecular networks by rich hydrogen bonds including strong O-H…N between solvent water and azide ion and O-H…O between solvent water and perchlorate ion, and weak hydrogen bonds C-H…O, and weak bifurcated hydrogen bonds C-H/C-H…N in which N atom of azide ion serving as bifurcated acceptor and two C-H groups as donors.     

Metal Complexes with Macrocyclic Ligands. Part XXXIX. Mono- and binuclear copper(II) complexes of a bridging bis[1, 4, 7-triazacyclononane]

The new bis-macrocycle 1, 1′-[(1H-pyrazol-3], 5-diyl)bis(methylene)bis[1, 4, 7-triazacyclononane] ( 1 ) was synthesized and its complexation with Cu²⁺ studied. Potentiometric and spectrophotometric titrations indicate that, in addition to the mononuclear species [Cu(LH₂)]⁴⁺, [Cu(LH)]³⁺, [CuL]²⁺, and [Cu(LH_?1)]⁺, binuclear complexes such as [Cu₂L]⁴⁺, [Cu₂(LH_?1)]³⁺, and [Cu₂(LH_-2)]²⁺ are also formed in solution. The stability constants and spectral properties of these are reported. The binuclear species [Cu₂(LH_?1)]³⁺ specifically reacts with an azide ion to give a ternary complex [Cu₂(LH_?1)(N₃)]²⁺, the stability and structure of which were determined spectrophotometrically and by X-ray diffraction, respectively. The two Cu²⁺ ions are in a square-pyramidal coordination geometry. The axial ligand is one of the N-atoms of the 1, 4, 7-triazacyclononane ring, whereas at the base of the square pyramid, one finds the other two N-atoms of the macrocycle, one N-atom of the pyrazolide and one of the azide, both of which are bridging the two metal centres. In [Cu₂(LH_?1)(N₃)]²⁺, a strong antiferromagnetic coupling is present, thus resulting in a species with a low magnetic moment of 1.36 B.M. at room temperature.     

Synthesis,crystal structure,and magnetism of a binuclear Cu(II) complex with double azido as asymmetric basal–apical end-on bridged ligand

A new binuclear copper(II) complex, [Cu₂(μ_1,1-N₃)₂(PP)₂)] ? 2ClO₄ (PP = 2,6-dipyrazol-1-yl-pyridine), was synthesized with double azide as asymmetric end-on bridge ligand and 2,6-dipyrazol-1-yl-pyridine as the terminal ligand. The crystal structure was determined by X-ray crystallography. Cu(II) is located in a distorted square pyramidal geometry, and azide bridges the equatorial-axial linking two Cu(II) atoms with a separation of 3.3595(11) Å. The fitting for the data of the variable-temperature (2–300 K) magnetic susceptibilities by using the Curie–Weiss law gives the Weiss temperature θ = ?7.830 K, indicating a very weak anti-ferromagnetic interaction between the bridging Cu(II) complexes.     

Synthesis,crystal structure,and properties of copper(II) and manganese(II) complexes with azide and 3,4-di(2′-pyridyl)-1,2,5-oxadiazole

Two transition metal complexes with azide and 3,4-di(2′-pyridyl)-1,2,5-oxadiazole (dpo), [Cu₂(dpo)₂(N₃)₄] (1), and [Mn(dpo)₂(N₃)₂] (2), have been synthesized and characterized by single-crystal X-ray diffraction. The Cu(II) complex is binuclear with double end-on (EO) azido bridges, in which each Cu(II) ion assumes a distorted square pyramidal geometry, and each EO azido bridge adopts a quasi-symmetric fashion. In contrast, the Mn(II) complex is mononuclear, in which the Mn(II) ion is ligated by two dpo ligands and two terminal azide ions, with a distorted octahedron geometry. Magnetic studies on the Cu(II) complex revealed that the double EO azido bridge mediates ferromagnetic coupling with J=12.8 cm⁻¹.     

catena‐Poly[[{4‐bromo‐2‐[2‐(dimethyl­amino)ethyl­imino­methyl]­phenol­ato}­copper(II)]‐μ‐azido]

The title complex, [Cu(C₁₁H₁₄BrN₂O)(N₃)]_n, is an inter­esting azide‐bridged polynuclear copper(II) compound. The Cu^II atom is five‐coordinated in a square‐pyramidal configuration, with one O and two N atoms of one Schiff base and one terminal N atom of a bridging azide ligand defining the basal plane, and another terminal N atom of another bridging azide ligand occupying the axial position. The {4‐bromo‐2‐[2‐(dimethyl­amino)ethyl­imino­meth­yl]phenolato}copper(II) moieties are linked by the bridging azide ligands, forming polymeric chains running along the b axis. Adjacent chains are further linked by weak Br⋯Br inter­actions into a sheet.     

(–)‐α‐Isosparteine copper(II) diazide

In the title complex, [Cu(N₃)₂(C₁₅H₂₆N₂)], the Cu atom is surrounded by the two N atoms of the chelating (?)‐α‐isosparteine ligand and another two N atoms from the two azide anions, forming a distorted CuN₄ tetrahedron. The two azide anions are terminally bound to the Cu^II atom, and the dihedral angle between the N_sparteine—Cu—N_sparteine and N_azide—Cu—N_azide planes is 50.0 (2)°.     

Changes in the conformational parameters of 1-allylbenzotriazole in a mixed halide π-complex [CuCl0.85Br0.15(C6H4N3CH2=CH2)] under the action of bromine atoms

Single crystals of [CuCl_0.85Br_0.15(C₆H₄N₃CH₂=CH₂)] (I) were obtained by alternating current electrochemical synthesis; their X-ray structural investigation has been carried out (DARCh automatic diffractometer, MoK _α radiation, θ/2θ scanning; 1460 reflections with F ≥ 4σ(F), R = 0.0517). The crystals are monoclinic, their space group is P2₁/c, a = 7.292(3) Å, b = 17.947(8) Å, c = 7.398(4) Å, β = 93.56(4)°, V = 966(1) ų, Z = 4). Complex I is close in structure to the previously investigated compound [CuCl(C₆H₄N₃CH₂=CH₂)] (II). In both structures, the trigonal-pyramidal surroundings of the copper atom include two halide atoms (one is apical), a nitrogen atom, and a C=C group. The Cu₂X₂ dimers are associated into {[Cu₂X₂(C₆H₅N₃CH₂=CH₂)]}_n layers due to the bridging function of the 1-allylbenzotriazole molecule. In spite of the similar coordination polyhedra of the metal atoms and identical bridging function of the ligand molecule in I and II, the differences in the conformation parameters of the allyl group π-coordinated by the copper(I) atom (trans-like in I and cis-like in II) caused by the presence of bromine atoms in the coordination sphere predetermine different structures of the organometallic [Cu₂X₂(C₆H₅N₃CH₂=CH₂)]₄ tetramer subunits in the layers and, as a consequence, formation of different crystal structures. Original Russian Text Copyright ? 2005 by E. A. Goreshnik, B. M. Mykhalichko, and V. N. Davydov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 174–178, January–February, 2005.     

Syntheses,Characterization, and Antibacterial Property of Polynuclear Cobalt(III) and Copper(II) Complexes Derived from Similar Tridentate Schiff Bases

An end-on azido-bridged trinuclear cobalt(III) complex [Co₃(L¹)₂(μ_1,1-N₃)₄(N₃)₂(OMe)(MeOH)] (I) and a phenolato-bridged dinuclear copper(II) complex [Cu₂(L²)₂(NCS)₂] (II), where L¹ is the deprotonated form of 2-((2-(dimethylamino)ethylimino)methyl)-4-fluorophenol, and L² is the deprotonated form of 2-((3-(dimethylamino)propylimino)methyl)-4-fluorophenol, have been prepared and characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files CCDC nos. 1023376 (I); 1023377 (II)). The Co atoms in complex I are in octahedral coordination, and the Cu atoms in complex II are in square pyramidal coordination. The antibacterial properties have been tested on some bacteria and yeast.     

Synthesis and crystal structure of new one-dimensional copper(II) complex [Cu4(En)2(μ1,1-N3)4(μ1,1,1-N3)2(μ1,3-N3)2]n

A new polymer azido-bridged copper(II) complex [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂] _n (I) (En = ethylenediamine) has been synthesized and crystallography characterized. Complex I shows one-dimensional coordination polymeric structure based on a tetranuclear cluster unit [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂], in which the azido ions display three different bridging modes.