Syntheses,crystal structures,and Jack bean urease inhibitory activities of copper(II) complexes derived from 4-tert-butyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide

Two new copper(II) complexes, [CuL(HL)]·ClO₄ (1) and [Cu₂Br₂L₂]·0.85H₂O (2), where L is the monoanionic form of 4-tert-butyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL), have been prepared. The complexes were characterized by infrared and UV–vis spectra, and single crystal X-ray diffraction. Complex 1 is a mononuclear copper(II) species and 2 is a bromido-bridged dinuclear copper(II) species. The Cu ion in 1 is in an octahedral coordination mode and that in 2 is trigonal-bipyramidal. The Jack bean urease inhibitory assay indicated that 2 is active, with IC₅₀ value of 20.6 ± 2.3 μmol L^?1, while 1 is inactive. Molecular docking of 2 with Jack bean urease was studied.     

Synthesis and structures of 3-chloro-N′-(2-hydroxy-benzylidene)benzohydrazide and its oxovanadium(V) complex

A new Schiff-base 3-chloro-N ′ -(2-hydroxybenzylidene)benzohydrazide (H₂BBH) and its oxovanadium(V) complex [VO(BBH)(OCH₃)]₂ have been synthesized and characterized by elemental analysis, infrared (IR) spectra, and single-crystal X-ray determination. Both the ligand and the complex crystallized in the monoclinic space group P2₁ /c. The Schiff-base coordinates to V through the phenolate O, the imine N, and the enolic O. In the centrosymmetric dimeric oxovanadium(V) complex, the V atom is six-coordinate in an octahedral geometry. The bond lengths related to the donor atoms in the complex are different from those in the ligand. The coordination of the ligand to V is also supported by IR spectra.     

Synthesis and crystal structures of two zinc(II) complexes derived from N-isopropyl-N′-[1-(2-methoxyphenyl)methylidene]ethane-1,2-diamine

Two isostructural mononuclear zinc(II) complexes, [ZnLBr₂] (I) and [ZnLI₂] (II), derived from the Schiff base N-isopropyl-N′-[1-(2-methoxyphenyl)methylidene]ethane-1,2-diamine (L), have been synthesized and characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The crystal of I is monoclinic: space group P2₁/n, a = 14.476(1) Å, b = 7.327(1) Å, c = 17.528(1) Å, β = 101.153(1)°, V = 1824.0(3) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 14.482(1), b = 7.329(1), c = 17.528(1)Å, β = 101.195(2)°, V = 1825.0(3)ų, Z = 4. The Zn atom in each complex is four-coordinated in a tetrahedral coordination, with one imine N and one amine N atoms of L, and two halide atoms. Both complexes and the Schiff base were tested in vitro for their antibacterial activities.     

Synthesis,characterization and crystal structures of copper(II), zinc(II) and vanadium(V) complexes,derived from 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide,with antibacterial activity

Three copper(II), zinc(II), and vanadium(V) complexes, [CuL(HL)]ClO₄ (1), [ZnL₂] (2) and [VO₂L] (3), where L is the anionic form of 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL), were prepared and characterized by IR, UV–vis and single-crystal X-ray determination. X-ray analysis indicates that the complexes are mononuclear species, with the Cu and Zn ions in 1 and 2 in octahedral coordination, and with the V ion in 3 in trigonal bipyramidal coordination. The hydrazone compound and the three complexes were evaluated for antibacterial activities. The copper complex has effective activities.     

Synthesis,structures, and insulin-like activity of oxidovanadium(V) complexes derived from 2-chloro-N′-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide

Three new oxidovanadium(V) complexes, [VOLL′] (L = 2-chloro-N′-(3-ethoxy-2hydroxybenzylidene)benzohydrazide, L′ = acetohydroxamate for 1, methylmaltolate for 2, and ethylmaltolate for 3), have been prepared. The complexes have been characterized by physicochemical methods and single-crystal X-ray determination. Vanadium in each complex is coordinated by the NOO donor set of L, the OO donor set of L′, and one oxido, forming octahedral coordination. The complexes were administered intragastrically to both normal and alloxan-diabetic mice for two weeks. The biological activities show that the complexes at doses of 10.0 and 20.0 mg V·kg^?1 can significantly decrease the blood glucose level in alloxan-diabetic mice, but the blood glucose level in the treated normal mice was not altered.     

Synthesis,characterization, and structures of copper(I) complexes with N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine

Two ligands, N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine (L¹ ) and N,N′-bis- [1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine (L² ) and their corresponding copper(I) complexes, [Cu(L ¹)₂]ClO₄ (1) and [Cu(L ²)₂]ClO₄ (2), have been synthesized and characterized by CHN analyses, ¹H-NMR, IR, and UV–Vis spectroscopy. The crystal structures of L¹ and [Cu(L ¹)₂]ClO₄ (1) were determined from single crystal X-ray diffraction. L¹ lies across a crystallographic inversion center and the C=N is approximately coplanar with the benzene ring and adopts E configuration. The coordination polyhedron about copper(I) in 1 is best described as a distorted tetrahedron. Quasireversible redox behavior is observed for the complexes.     

Synthesis and crystal structures of Zn(II) complexes with N,N′-bis[(1-(2-pyridyl)ethylidene)propane-1,3-diamine and N,N′-bis[(1-(2-Pyridyl)ethylidene)ethane-1,2-diamine1

Two new zinc complexes, [Zn(Ppd)I]ClO₄ (I) and [Zn(Ped)I]ClO₄ (II), where Ppd and Ped are the Schiff bases N,N??-bis[(1-(2-pyridyl)ethylidene)propane-1,3-diamine and N,N??-bis[(1-(2-pyridyl)ethylidene)ethane-1,2-diamine, respectively, have been synthesized and characterized by means of elemental analysis, infrared spectroscopic, molar conductivity, and single crystal X-ray diffraction. The crystal of I is tri-clinic: space group $P\bar 1$ a = 8.421(2), b = 9.143(2), c = 13.166(3) ?, ?? = 92.521(5)°, ?? = 94.498(3)°, ?? = 94.232(4)°, V = 1006.6(4) ?³, Z = 2. The crystal of II is triclinic: space group $P\bar 1$ , a = 8.219(1), b = 8.483(1), c = 14.733(2) ?, ?? = 80.058(1)°, ?? = 81.960(1)°, ?? = 89.300(1)°, V = 1001.8(2) ?³, Z = 2. The zinc atom in the complexes assumes a distorted square pyramidal geometry through coordination by two pyridine N atoms and two imine N atoms of the Schiff base at the basal plane, and by a I atom at the apical position.     

Synthesis,crystal structure and DFT calculations of octahedral nickel(II) complexes derived from N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide

The two new nickel(II) complexes, [Ni(HL)(L)](NO₃)?H₂O (1) and [Ni(L)₂] (2) (where HL/L = N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide), have been synthesized and characterized by elemental analysis, spectroscopic, magnetic susceptibility, and cyclic voltammetric measurements. Single-crystal X-ray analysis of [Ni(HL)(L)](NO₃)?H₂O (1) and [Ni(L)₂] (2) has revealed the presence of a distorted octahedral geometry around nickel(II). The X-ray and spectral characterizations have confirmed the existence of the keto-enol form of the ligands in the complexes. The electronic structures and spectral properties of the ligands and the complexes have been explained by DFT and TDDFT calculations. Superoxide dismutase activity of these complexes has also been measured.     

Syntheses and crystal structures of transition metal complexes of 1,1′-bisacetylacetoferrocene

Bimetallic complexes 3a–e of 1,1′-bisacetylacetoferrocene (2) were prepared by reactions of transition metal acetates M(OAc)₂ (M?=?Co²⁺, Mn²⁺, Cu²⁺, Ni²⁺, Zn²⁺) with the 2 in refluxing methanol. The X-ray structures of the cobalt and manganese complexes were determined showing very similar centrosymmetric macrocyclic dimeric frameworks constituted by linkage of two Co²⁺ or Mn²⁺ ions and two 1,1′-diacetoacetylferrocene units with two additional methanols as bridges dividing this macrocyclic framework into two small cyclic subunits. The UV-Vis spectra and electronic properties were also studied.     

Tricarbonylrhenium(I) bromide complexes with N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine–syntheses,structures, electrochemical and spectroscopic studies

Two rhenium(I) complexes, [Re(CO)₃Br(L ⁿ )] (n = 1, 2), (L¹= N,N′-bis[1-(4-chlorophenyl)ethylidene]ethane-1,2-diamine and L² = N,N′-bis[1-(4-nitrophenyl)ethylidene]ethane-1,2-diamine) have been synthesized and characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The molecular structure of [Re(CO)₃Br(L¹)] is a distorted octahedron around rhenium with one Br, facial arrangement of three CO's, and one diimine. The UV-Vis spectra of the complexes have metal-to-ligand charge transfer bands increasing in wavelength when the L² ligand is replaced by L¹, in agreement with the oxidation potential of the complexes.     

Synthesis,crystal structures,and selected properties of Cu(II) and Zn(II) complexes with in situ formed 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide

Cu(C₁₀H₁₁O₂N₂)₂ (1) and [Zn(C₁₀H₁₂O₂N₂)₂(H₂O)₂](NO₃)₂ (2) were synthesized and characterized by elemental analysis, FT-IR spectra, UV-Vis absorption spectroscopy, and X-ray single-crystal diffraction. Both complexes show distorted octahedral geometry. In 1, Cu(II) is coordinated by four oxygen atoms from four ligands and two nitrogen atoms from two ligands. In 2, Zn(II) is coordinated by two oxygen atoms and two nitrogen atoms from two ligands, and two water molecules. The crystal structures suggest that original ligand o-carboxybenzaldehyde salicyloylhydrazone (C₁₅H₁₂O₄N₂) changed into acetone salicyloylhydrazone (C₁₀H₁₂O₂N₂). The TG-DTG curves of these complexes indicate two different decomposition processes. 1 and 2 display catalytic activities to decomposition of hydrogen peroxide. Interaction between the complexes and DNA studied by UV-Vis titration shows the insert interaction.     

Synthesis and X-ray crystal structures of N′-(2-hydroxy-5-methoxybenzylidene)-4-dimethylaminobenzohydra zide and its oxovanadium(V) complex with catalytic property

A new benzohydrazone compound N′-(2-hydroxy-5-methoxybenzylidene)-4-dimethylaminobenzohydrazide (H₂L) and its oxovanadium(V) complex [VOL(BHA)] · H₂O, where HBHA is benzohydroxamic acid, were prepared and structurally characterized by physic-chemical methods and single crystal X-ray diffraction. The benzohydrazone compound crystallizes in the monoclinic space group C2/c with a = 35.5873(12), b = 10.4628(4), c = 18.6059(6) Å, β = 109.499(1)°, V = 6530.4(4) ų, Z = 16, R ₁ = 0.0603, and wR ₂ = 0.1575. The oxovanadium(V) complex crystallizes in the triclinic space group $P\bar 1$ with a = 7.4775(4), b = 9.7837(5), c = 17.7076(8) Å, α = 99.457(2)°, β = 98.699(2)°, γ = 101.429(2)°, V = 1229.7(1) ų, Z = 2, R ₁ = 0.0431, and wR ₂ = 0.0937. X-ray structural analysis indicates that the benzohydrazone ligand L₂-coordinates to the V atom through the phenolate O, imino N, and enolic O atoms. The V atom in complex I is coordinated by one benzohydrazone ligand and one BHA ligand, as well as one oxo O atom, forming an octahedral coordination. The crystal structures of H₂L and I are stabilized by hydrogen bonds. Complex I is an effective catalyst for sulfoxidation.     

Synthesis,crystal structure,and urease inhibition of [N′-(3,5-dibromo-2-hydroxybenzylidene)isonicotinohydrazido]-(benzohydroxamato)oxovanadium(V)

A new oxovanadium(V) complex [VOL(BZH)] was prepared by the reaction of [VO(Acac)₂] (Acac = acetylacetonate) with N′-(3,5-dibromo-2-hydroxybenzylidene)isonicotinohydrazide (H₂L) and benzohydroxamic acid (HBZH) in methanol. Crystal and molecular structure of the complex was determined by elemental analysis, infrared spectra and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group P2₁/c, with unit cell dimensions a = 11.424(1), b = 12.012(1), c = 19.565(2) Å, β = 93.487(3)°, V = 2679.8(4) ų, Z = 4, GOOF = 1.152, R ₁ = 0.0593, and wR ₂ = 0.1942. The V atom is in octahedral coordination. Thermal stability and the inhibition of urease of the complex were studied.     

Syntheses and crystal structures of two maleonitriledithiolate complexes containing the 1-(R-benzyl)pyrazinium cation (R = 4′-nitro or 4′-bromo)

The complexes [NO₂BzPz]₂[Ni(mnt)₂] (1) and [BrBzPz]₂[Pd(mnt)₂] (2) have been prepared by reaction of Na₂mnt, NiCl₂·6H₂O or PdCl₂, and the corresponding 1-(R-benzyl)pyrazinium bromide salt (R = 4′-nitro, R = 4′-bromo). Crystallographic data for 1: monoclinic, P2₁/n, a = 7.3494(15), b = 15.223(3), c = 15.054(3)?Å, β = 102.42(3)°, V = 1644.8(6)?ų, Z = 2. Data for 2: monoclinic, P2₁/n, a = 7.399(2), b = 19.024(4), c = 12.224(2)?Å, β = 94.62(3)°, V = 1715.0(7)?ų, Z = 4. In both complexes, the [M(mnt)₂]^2? anion has a centre of symmetry at the metal atom and two cations are related to each other by the symmetry centre. The [M(mnt)₂]^2? anion exhibits a quasi-planar structure in both complexes, which show similar crystal packing.     

Syntheses and crystal structures of cobalt(II) and zinc(II) complexes with 4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate

Abstract Sodium 4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate (1) is synthesized by the sulfonation of 6-hydroxybiochanin A and its structure is characterized by elemental analysis, ¹H-NMR, and IR spectroscopy. It is assembled with cobalt(II) or zinc(II), hexaquacobalt(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (2) and hexaquazinc(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (3) are obtained and characterized by IR spectroscopy. Simultaneously, their three-dimensional structures are determined by single-crystal X-ray analysis. It turns out that 2 and 3 are isomorphous and crystallize in the triclinic crystal system, space group P-1. Hydrophilic regions are defined by O–H···O hydrogen bonds involving the coordinated water molecules, the included water molecules, and sulfonate groups. Aromatic π...π stacking interactions assemble the isoflavone skeletons into columns and these columns formed hydrophobic regions. The sulfonate group is an important bridge as a structural link between the hydrophilic regions and the hydrophobic regions. Hydrogen bonds, π...π stacking interactions and the electrostatic interactions assemble 2 and 3 into three-dimensional network structures. Graphical abstract Sodium 4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate (1) is synthesized and assembled with cobalt(II) or zinc(II). Hexaquacobalt(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (2) and hexaquazinc(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (3) are obtained and determined by single-crystal X-ray analysis. It turns out that 2 and 3 are isomorphous and assembled into three-dimensional network structures, characterized by hydrophilic regions defined by hydrogen bonds involving the coordinated water molecules, the included water molecules, and the sulfonate groups and by hydrophobic columns, formed by the isoflavone skeletons, interacting through π...π stacking interactions.      

Synthesis and crystal structures of cobalt(III), copper(II), nickel(II) and zinc(II) complexes derived from 4-methoxy-N′-(pyridin-2-ylmethylene)benzohydrazide with urease inhibitory activity

Abstract

Urease catalyzes the decomposition of urea into ammonia, which has harmful effects on both human health and fertile soil. Aiming at exploring novel urease inhibitors, a series of hydrazone compounds and their Co^III, Cu^II, Ni^II, and Zn^II complexes were prepared from 4-methoxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL). They are [CoClL(NCS)] (1), [CoL₂]·Cl·CH₃OH·H₂O (2), [CuL(NCNCN)]_n·nCH₃OH (3), [NiL(HL)]·ClO₄·CH₃OH (4) and [ZnClL(OH₂)]·CH₃OH (5). The compounds were characterized by physico-chemical methods. Structures of the complexes were further confirmed by single crystal X-ray diffraction. The metal ions in 1, 3, and 5 display square pyramidal coordination and 2 and 4 display octahedral coordination. The inhibitory effects of the compounds on Jack bean urease were evaluated. The results showed that 3 has effective urease inhibitory activity, with IC₅₀ value of (7.3?±?1.0) μmol L^?1.     

Syntheses,crystal structures,and fluorescence of two complexes constructed by N ′-(pyridin-2-ylmethylene)-2-( 1H -1,2,4-triazol-1-yl)acetohydrazide

Two new binuclear complexes, Cd₂(HL)₂(NO₃)₄?·?(CH₃OH)₂ (1) and Cu₂(L)₂(ClO₄)₂ (2), based on N′-(pyridin-2-ylmethylene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide (HL) and Cd(II) and Cu(II) salts have been synthesized and characterized by single crystal X-ray diffraction. Hydrogen bonds and π–π interactions extend both binuclear molecules, a 3-D supramolecular framework for 1 and 1-D staggered chains for 2. Fluorescence of both complexes is discussed.     

Synthesis and structural characterization of copper(II) complexes with the 2′-[1-(2-pyridinyl)ethylidene]oxalohydrazide ligand

The octahedral copper(II) complex with two 2-[1-(2-pyridinyl)ethylidene]oxalohydrazide molecules was synthesized from bis(acetylacetonato)copper(II) and 2-[1-(2-pyridinyl)ethylidene]oxamohydrazide (Hapsox). The complex is unstable when not in solution. X-ray analysis confirmed the tridentate coordination of the ligands in the monoanionic form. In addition, the stable tetrahedral copper(II) complex with one ligand molecule coordinated as a tridentate in the dianionic form was prepared by direct synthesis from Cu(NO₃)₂·3H₂O and Hapsox, and characterized by elemental analysis, magnetic measurements and by i.r. and u.v./vis. spectrophotometry.     

Synthesis,structural studies,and antibacterial activity of zinc,copper, and silver complexes derived from N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide

The multidentate Schiff-base ligand N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide (HL) has been prepared. Reaction with zinc, copper, and silver nitrate afford three complexes, [Zn(HL′)₂](NO₃)₂·3H₂O (1), {[Cu₂(L)₂(NO₃)(H₂O)₂]·NO₃}_n (2) and {[Ag₂(L)₂]·3H₂O}_n (3). These complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. In 1, HL is a neutral tridentate ligand, whereas in 2 and 3, HL is a deprotonated tetradentate ligand. The hydrogen bonding interactions between NO₃^? and the host framework result in various supramolecular polymeric structures: a 2-D layer for 1 and 3-D network for 2 and 3. The antibacterial activities of these complexes have been investigated and the results indicate that 3 showed good antibacterial activities.     

Synthesis and crystal structure of new cobalt(II) and copper(II) complexes with deprotonated N -[2′-(4-methyl) pyrimidinyl]-2-nitrobenzenesulfonylurea

Cobalt(II) and copper(II) complexes with deprotonated N-[2′-(4-methyl)pyrimidinyl]-2-nitrobenzenesulfonylurea were synthesized and their structures were characterized by IR spectrum, elemental analysis and X-ray diffraction. The deprotonated sulfonylurea is a bidentate ligand to Co(II) or Cu(II) in octahedral geometry. In the packing diagrams of the complexes, C–H ··· O hydrogen bonds are observed. The UV and fluorescence spectra of the complexes are described, and the thermogravimetric analyses of the complexes were performed.