Synthesis and crystal structures of two Schiff base copper(II) complexes derived from 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol

A centrosymmetric mononuclear copper(II) complex, [Cu(L¹)₂] (I), and a phenolate oxygen-bridged dinuclear copper(II) complex, [Cu₂(L²)₄] (II) (HL¹ = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol, HL² = 4-chloro-2-(cyclohexylimino-methyl)phenol), were synthesized and characterized by elemental analyses, IR, and single crystal X-ray diffraction. The crystal of I is monoclinic: space group {ITP}2₁/n, a = 13.396(3), b = 5.339(1), c = 19.740(4) Å, β = 108.64(3), V = 1337.8(5) ų, {ITZ} = 2. The crystal of II is monoclinic: space group P2₁, a = 9.157(2), b = 22.715(4), c = 12.169(2) Å, = 95.28(3), {ITV} = 2520.4(8) Å3, {ITZ}= 2. The Cu atom in I, lying on the inversion center, is four-coordinate in a square planar geometry with two phenolate oxygen and two imine nitrogen atoms. Each Cu atom in II is five-coordinate in a square pyramidal geometry with two phenolate oxygen and two imine nitrogen atoms from two L² ligands defining the basal plane and with one phenolate oxygen atom of another L² ligand occupying the apical position.     

Syntheses and crystal structures of two copper(II) complexes derived from 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol

Two new copper(II) complexes, [CuL₂] (1) and [Cu₂L₂(NCS)₂] · 2CH₃CN (2) (HL = 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol), have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Complex 1 was synthesized by reaction of HL with copper(II) acetate in methanol, while 2 was synthesized by adding ammonium thiocyanate to a methanol/acetonitrile (V : V = 2 : 1) solution of 1. Complex 1 crystallizes in the P2₁/n space group, and the thiocyanato-bridged dinuclear copper(II) complex, 2, crystallizes in the Pbcn space group. The Cu in 1 is four-coordinate square-planar with two imine N and two phenolate O atoms from two Schiff-base ligands. The Cu in 2 is five-coordinate square-pyramidal with NNO donor atoms of one Schiff-base ligand and one N atom of a bridging thiocyanate ligand defining the basal plane, and with one S atom of another bridging thiocyanate ligand occupying the apical position.     

Synthesis,crystal structures,and antimicrobial activity of copper(II) and zinc(II) complexes derived from 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol

An end-to-end azido-bridged dinuclear copper(II) complex [Cu₂L₂(μ_1,3-N₃)](NO₃) (I) and a mononuclear zinc(II) complex [ZnCl₂(HL)] ? CH₃OH (II), where L is 2-brom-4-chloro-6-[(2-morpholin- 4-ylethylimino)methyl]phenolate, have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination (CIF files CCDC nos. 1415217 (I), 1415218 for (II)). The crystal of I is monoclinic: space group C2/c, a = 28.684(2), b = 7.1787(5), c = 18.292(1) Å, β = 117.887(3)°, V = 3329.1(4) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 10.8207(9), b = 12.3398(7), c = 14.9477(7) Å, β = 93.473(3)°, V = 1992.2(2) ų, Z = 4. The Schiff base ligand in I coordinates to the Cu atom through the phenolate O, imine N, and morpholine N atoms, while the Schiff base ligand in II coordinates to the Zn atom through the phenolate O and imine N atoms, with the morpholine N atom protonated. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.     

Synthesis and crystal structures of cobalt(III) and zinc(II) complexes derived from 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol with urease inhibitory activity

A new mononuclear cobalt(III) complex, [CoL₂(N₃)]₂ · CH₃OH (I), and a new mononuclear zinc(II) complex, [ZnLCl(CH₃OH)] (II) (HL = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol), were prepared and structurally characterized by elemental analyses, infrared spectroscopy, and single- crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 18.742(2) Å, b = 15.197(2) Å, c = 25.646(2) Å, β = 125.996(3)°, V = 5909.8(11) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 7.257(1) Å, b = 24.707(2) Å, c = 9.637(1) Å, β = 101.557(2)°, V = 1692.9(3) ų, Z = 4. The Co atom in I is in an octahedral coordination, and the Zn atom in II is in a trigonal-bipyramidal coordination. The urease inhibitory test shows that complex I has strong urease inhibitory activity, while complex II has no activity.     

Synthesis,crystal structures,and antibacterial activity of copper(II) and cobalt(III) complexes derived from 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol

A new tetranuclear copper(II) complex (I) and a new mononuclear cobalt(III) complex (II) have been synthesized from the Schiff base compound 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol. The complexes have been characterized by physico-chemical and spectroscopic methods, as well as single crystal X-ray determination (CIF files CCDC nos. 1447778 (I) and 1447779 (II)). The Cu atoms in complex I are in square pyramidal coordination, and the Co atom in complex II is in octahedral coordination. Crystal structures of the complex are stabilized by hydrogen bonds and π···π interactions. The complexes and the Schiff base compound were assayed for antibacterial activities against three Gram-positive bacterial strains (B. subtilis, S. aureus, and St. faecalis) and three Gram-negative bacterial strains (E. coli, P. aeruginosa, and E. cloacae) by MTT method. As a result, the complexes showed effective antimicrobial activity against the microorganisms tested.     

Crystal structures of bis(AZIDO)bis(2-morpholin-4-ylethylamino)copper(II) and bis{2,4-dibromo-6-[(2-morpholin-4-ylethylimino)methyl] phenolato}copper(II)

Two new copper(II) complexes [Cu(MEA)₂(N₃)₂] (1) and [Cu(BMP)₂] (2), where MEA and BMP are 2-morpholin-4-ylethylamine and 2,4-dibromo-6-[(2-morpholin-4-ylethylimino)methyl]phenolate respectively, are prepared and characterized using elemental analysis, FT-IR spectroscopy, and X-ray single crystal diffraction. The crystal of 1 belongs to the triclinic system, space group P-1, with a = 6.661(2) Å, b = 8.440(3) Å, c = 8.913(3) Å, α = 102.032(3)°, β = 107.899(2)°, γ = 98.242(3)°, V = 454.6(3) ų, Z = 1, D _c = 1.490 g/cm³, R ₁ = 0.0226, and wR ₂ = 0.0564. The crystal of 2 belongs to the monoclinic system, space group P2₁/c, with α = 7.0707(7) Å, b = 15.438(1) Å, c = 14.227(1) Å, β = 96.659(2)°, V = 1542.5(3) ų, Z = 2, D _c = 1.821 g/cm³, R ₁ = 0.0437, and wR ₂ = 0.1041. In each complex, the Cu atom is in a square planar coordination. The molecules of 1 are linked through intermolecular N-H...N and N-H...O hydrogen bonds to form layers parallel to the ab plane. The molecules of 2 are linked through intermolecular C-H...Br hydrogen bonds to form a 3D network.     

Synthesis,crystal structures,and antimicrobial activity of two thiocyanato-bridged dinuclear copper(II) complexes derived from 2,4-dibromo-6-[(2-diethylaminoethylimino)methyl]phenol and 4-nitro-2-[(2-ethylaminoethylimino)methyl]phenol

A pair of structurally similar thiocyanato-bridged dinuclear Cu(II) complexes derived from the Schiff bases 2,4-dibromo-6-[(2-diethylaminoethylimino)methyl]phenol and 4-nitro-2-[(2-ethylaminoethylimino)methyl]phenol has been prepared and characterized by physico-chemical and spectroscopic methods. Each Cu atom is five-coordinate in a square-pyramidal geometry, with one O and two N atoms of one Schiff base ligand and one N atom of a bridging thiocyanate ligand defining the basal plane, and with one terminal S atom of another bridging thiocyanate ligand occupying the apical position. Antimicrobial activities of the Schiff bases and the two complexes have been tested. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Solvent-influenced syntheses and crystal structures of two azido-bridged polynuclear copper(II) complexes derived from 2-[(3-methylaminopropylimino)methyl]phenol with urease inhibitory activities

An end-on azido-bridged dinuclear Cu(II) complex, [Cu₂L₂(μ_1,1–N₃)₂]·CH₃OH, and an end-on azido-bridged polynuclear Cu(II) complex, [CuL(μ_1,1–N₃)]_n, derived from the Schiff base 2-[(3-methylaminopropylimino)methyl]phenol (HL), were synthesized and characterized by physico-chemical and spectroscopic methods. The two complexes were synthesized and crystallized with different solvents, methanol for [Cu₂L₂(μ_1,1–N₃)₂]·CH₃OH and ethanol for [CuL(μ_1,1–N₃)]_n. The Cu atom in each complex is five-coordinate in a square pyramidal geometry with one O and two N atoms of L, and one N atom of an azide ligand defining the basal plane, and with one N atom of another azide ligand occupying the apical position. The urease inhibitory activities of both complexes were evaluated.     

Synthesis, crystal structures, and biological activity of zinc(II) complexes derived from 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol

Two new Schiff base zinc(II) complexes, [ZnBr₂L] (I) and [ZnCl₂L] (II), where L is 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol, were synthesized and characterized by physico-chemical methods and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n a = 7.250 (2), b = 16.136 (3), c = 15.802 (3) Å, β = 90.027 (3)°, V = 1848.6 (7) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.177 (3), b = 15.970 (4), c = 15.689 (3), β = 91.674 (3)°, V = 1797.5 (9) ų, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two halide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.     

Synthesis,crystal structures,and antimicrobial activity of a pair of isostructural dinuclear copper(II) complexes derived from 4-nitro-2-[(2-diethylaminoethylimino)methyl]phenol

A pair of isostructural azido- or thiocyanato-bridged centrosymmetric dinuclear copper(II) complexes, [Cu₂L₂(μ_1,3-N₃)₂] (1) and [Cu₂L₂(μ_1,3-NCS)₂] (2), derived from the Schiff base ligand 4-nitro-2-[(2-diethylaminoethylimino)methyl]phenol (HL), have been synthesized and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Each Cu atom in the complexes is five-coordinate in a square pyramidal geometry by one O and two N atoms of one Schiff base ligand, and by two terminal donor atoms from two bridging azide or thiocyanate ligands. Both the azide and thiocyanate ligands adopt end-to-end bridging mode in the complexes. The distance between the two copper atoms is 5.205(2) Å for (1) and 5.515(2) Å for (2). The antimicrobial activity of the complexes has been tested.     

Syntheses and crystal structures of copper(II) and nickel(II) complexes derived from 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol

A new centrosymmetric mononuclear copper(II) complex [Cu(L)₂](ClO₄)₂ (I) and a new centrosymmetric mononuclear nickel(II) complex [Ni(L)₂(MeOH)₂](ClO₄)₂ (II), where L is the zwitterionic ligand 2-bromo-4-chloro-6-[(2-methylammonioethylimino)methyl]phenolate, have been prepared from the Schiff base 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol with copper perchlorate and nickel perchlorate, respectively. The complexes were characterized by elemental analysis, infrared spectra, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408054 (I) and 1407973 (II)). Complex I crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.7736(4), b = 21.608(1), c = 8.5194(4) Å, β = 93.907(2)°, V = 1427.7(1) ų, Z = 2, R ₁ = 0.0546, and wR ₂ = 0.1531. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 21.324(3), b = 16.821(2), c = 9.425(1) Å, β = 90.114(2)°, V = 3380.5(7) ų, Z = 4, R ₁ = 0.0693, and wR ₂ = 0.1627. The Cu atom in I is in square planar coordination, and the Ni atom in II is in octahedral coordination.     

Solvent-controlled synthesis and crystal structures of a pair of azido-bridged copper(II) complexes constructed from 1-[(3-dimethylaminopropylimino)methyl]naphthalen-2-ol

A pair of azido-bridged copper(II) complexes, [Cu₂L₂(μ _1,1-N₃)₂] (1) and [Cu₂L₂(μ _1,3-N₃)₂] · H₂O (2) (HL = 1-[(3-dimethylaminopropylimino)methyl]naphthalen-2-ol), have been obtained from an identical synthetic procedure and starting materials with solvents as the only independent variable. Complex 1 was synthesized and crystallized using the anhydrous methanol, while 2 was synthesized and crystallized using 95% ethanol. Both complexes show interesting self-assembled structures in their crystals as elucidated by X-ray analysis. The end-on azido-bridged dinuclear 1 crystallizes in the P 1 space group. The end-to-end azido–bridged polymeric 2 crystallizes in the P2₁/c space group.     

Syntheses and crystal structures of two Schiff-base copper(II) complexes with antibacterial activities

Two structurally similar trinuclear complexes, [Cu(Cu(μ-Cl)₂L1)₂] (1) and [Cu(Cu(μ-Cl)₂L2)₂] (2) (HL1 = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol, HL2 = 1-[(2-piperidin-1ylethylimino)methyl]naphthalen-2-ol), have been synthesized and structurally characterized. Both complexes are bridged trinuclear compounds. The central Cu in each complex is in an octahedral environment with two phenolate and four bridging chlorides. The symmetry-related terminal Cu in each complex is square pyramidal with one phenolate oxygen, one imine nitrogen and one amine nitrogen of the Schiff-base ligand, one Cl^? in the basal plane, and one bridging Cl^? in the apical position. The complexes and Schiff bases were tested in vitro for their antibacterial activities.     

Crystal structure of 4,4-bipyridine-containing complexes of copper(II) nitrate with 1-[(2-Hydroxyethylimino)methyl]naphthalen-2-ol and 2-[(2-hydroxyethylimino)methyl]phenol

The crystal structures of (μ-4,4-bipyridine)-di(nitrato-1-[(2-hydroxyethylimino)methyl]naphthalen-2-olocopper (I) and catena-di(μ-4,4’-bipyridine)di(μ-4,4’-bipyridine)-di(nitrato-2-[2-(hydroxyethylimino) methyl]phenolocopper)diaquacopper(II) nitrate (II) were determined. In the crystal of I, each of the two copper atoms coordinates a singly deprotonated tridentate azomethine molecule, a nitrate ion, and bipyridine, which functions as a bridge between the central atoms. The copper coordination polyhedron is a slightly distorted tetragonal pyramid with the base formed by the imine and bipyridine nitrogen atoms and the phenol and alcohol oxygen atoms. The axial site in the pyramid is occupied by the oxygen atom of the monodentate nitrate groups. In the trinuclear structure II with C₂ crystal chemical symmetry, the terminal coordination unit is composed through copper coordination of monodeprotonated 2-[2-(hydroxyethylimino)methyl]phenol, bipyridine, and the nitrate anion. In the crystal, the trinuclear molecules form infinite ribbons along the z axis in which the pyridine molecules perform the bridging function. The central copper atom has an octahedral configuration formed by the nitrogen atoms of four 4,4’-bipyridine molecules and oxygen of two water molecules.     

Sulfanilamide copper(II) chelates with 2-[(2-hydroxyphenyl-imino)methyl]phenolom and 1-[(2-hydroxyphenylimino)-methyl]naphthalen-2-ol

2-[(2-Hydroxyphenylimino)methyl]phenol (H²L¹) and 1-[(2-hydroxyphenylimino)methyl]naphthalen-2-ol (H²L²) reacted with copper(II) acetate hydrate and sulfanilamide (Sf¹), sulfathiazole (Sf²), sulfaethidole (Sf³), sulfadiazine (Sf⁴), and sulfadimidine (Sf⁵) in ethanol to give mixed-ligand copper chelates with the composition Cu(Sf^1–5)(L^1–2) · n H₂O (n = 1, 2). All these complexes are monomeric. Salicylaldehyde imines (H₂L¹ and H₂L²) behave as doubly deprotonated tridentate O,N,O ligands, whereas sulfanilamides (Sf^1–5) are unidentate ligands. Thermolysis of the synthesized complexes includes dehydration at 70–90°C, followed by complete thermal decomposition (290–380°C). The complexes [Cu(Sf¹)(L¹)] · 2H₂O and [Cu(Sf³)(L¹)] · H₂O at a concentration of 10⁻⁴ M inhibited growth and reproduction of 100% of human myeloid leukemia cells (HL-60). The inhibitory effect was 90 and 75%, respectively, at a concentration of 10⁻⁵ M, whereas no antitumor activity was observed at a concentration of 10⁻⁶ M.     

Zinc(II) and nickel(II) complexes derived from 2-bromo-6-[(2-Isopropylaminoethylimino)methyl]phenol: Synthesis,structures, and antimicrobial activity

The Schiff base 2-bromo-6-[(2-isopropylaminoethylimino)methyl]phenol (HL), derived from 3-bromosalicylaldehyde with N-isopropylethane-1,2-diamine, and its zinc(II) and nickel(II) complexes [Zn(HL)₂(NCS)₂] (I) and [Ni(HL)₂(N₃)₂)] · 0.25H₂O (II) have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is orthorhombic: space group Pbca, a = 13.6928(9), b = 9.7203(6), c = 22.926(1) Å, V = 3051.4(3) Å^{3, Z} = 4. The crystal of II is triclinic: space group $P\bar 1$ , a} = 8.0212(7), b = 12.744(1), c = 15.590(2) Å, α = 104.802(3)°, β = 90.561(3)°, γ = 103.130(3)°, V = 1496.6(2) Å^{3, Z} = 1. The zwitterionic Schiff base ligands coordinate to the metal atoms through phenolate O, imine N, and amine N atoms. Each metal atom in the complexes is in octahedral coordination. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.     

Syntheses,characterizations, crystal structures,antibacterial and SOD-like activities of nickel(II) and copper(II) complexes with 2-((Z)-(4-methoxyphenylimino)methyl)-4,6-dichlorophenol

Three mononuclear nickel(II) and copper(II) complexes, [Ni(L)₂(py)₂] (1), [Ni(L)₂(DMF)(H₂O)] (2), and [Cu(L)₂] (3), where HL = 2-((Z)-(4-methoxyphenylimino)methyl)-4,6-dichlorophenol, py = pyridine and DMF = N,N-dimethylformamide, have been synthesized and their structures determined by single crystal X-ray analysis. Complexes 1–3 crystallized in the monoclinic system of the space groups C2/c, P2_1/n, and P2_1/c, respectively. The crystal structures of 1 and 2 present an octahedral geometry at the metal center and 3 shows a square-planar geometry. The FT-IR spectra, UV–vis spectra, and magnetic susceptibility measurements agree with the observed crystal structures. EPR spectra indicate a d_x2–y2 ground state (g_|| > g_⊥ > 2.0023 and A_|| > A_⊥) for 3 at RT and LNT. The results of simultaneous TG-DTA analyses of 1 and 3 showed the final degradation products are NiO for 1 and CuO for 3. The Schiff base (HL) behaves as monobasic bidentate ligand possessing N and O donor atoms. Electrochemical properties for the complexes are similar and involve two irreversible redox processes. Complex 3 exhibits the ability to inhibit jack bean urease, although its Schiff base has no ability to inhibit urease. Complex 1 exhibits more active scavenging effects against O₂^? than HL, 2 and 3 under the same conditions. Antibacterial screening activities of these complexes were also investigated.     

Synthesis,crystal structures and properties of two copper(II) 2-aminomethylbenzimidazole complexes

Two new Cu^II complexes, [Cu(Hambi)₂(ClO₄)₂] and [Cu(Hambi)₂(dca)₂] (Hambi = 2-aminomethylbenzimidazole) have been prepared and characterized by X-ray diffraction, electronic paramagnetic resonance (e.p.r.) and i.r. analyses. Both complexes exhibit an elongated octahedral coordination environment with two Hambi ligands situated at the equatorial positions in a trans fashion [Cu—N bond distances range from 1.940(9) to 2.031(9) Å]. In the second complex, a new coordination mode, in which dicyanamide coordinates to copper(II) as a monodentate ligand with the amide nitrogen atom, was observed.     

Syntheses,crystal structures,and urease inhibitory properties of copper(II) and zinc(II) complexes with 2-bromo-4-chloro-6-[(2-dimethylaminoethylimino)methyl]phenol

A new copper(II) complex, [CuL(μ _1,1-N₃)] _n (1), and a new zinc(II) complex, [ZnL(μ ₂-acetato-O, O′)₂] _n (2) (HL = 2-bromo-4-chloro-6-[(2-dimethylaminoethylimino)methyl]phenol), were prepared and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Complex 1 is an end-on azide-bridged polynuclear copper(II) complex and 2 is a syn–anti bidentate acetate-bridged polynuclear zinc(II) complex. Each metal in the complex is five-coordinate with square-pyramidal geometry. Complex 1 shows good urease inhibitory properties, while 2 does not.     

Synthesis and physiochemical studies on binuclear Cu(II) complexes derived from 2,6-[(N-phenylpiperazin-1-yl)methyl]-4-substituted phenols

Preparation of the ligands HL¹ = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-ethylphenol; HL² = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-methoxyphenol and HL³ = 2,6-[(N-phenylpiperazin-1-yl)methyl]-p-nitrophenol are described together with their Cu(II) complexes with different bridging units. The exogenous bridges incorporated into the complexes are: hydroxo [Cu₂L(OH)(H₂O)₂](ClO₄)₂.H₂O (L¹=1a, L² =1b, L³ =1c), acetato [Cu₂L(OAc)₂]ClO₄.H₂O (L¹ =2a, L² =2b, L³ =2c) and nitrito [Cu₂L¹(NO₂)₂(H₂O)₂]ClO₄.H₂O (L¹=3a, L² =3b, L³ =3c). Complexes1a,1b,1c and2a,2b,2c contain bridging exogenous groups, while3a,3b,3c possess only open μ-phenolate structures. Both the ligands and complexes were characterized by spectral studies. Cyclic voltammetric investigation of these complexes revealed that the reaction process involves two successive quasireversible one-electron steps at different potentials. The first reduction potential is sensitive to electronic effects of the substituents at the aromatic ring of the ligand system, shifting to positive potentials when the substituents are replaced by more electrophilic groups. EPR studies indicate very weak interaction between the two copper atoms. Various covalency parameters have been calculated.