Syntheses,characterization, crystal structures and fluorescence property of Zinc(II) complexes with Schiff bases

Two new mononuclear Schiff base zinc(II) complexes, [ZnCl₂(L¹)] ? MeOH (I) and [Zn(L²)₂] (II) (L¹ = 2-bromo-4-chloro-6-[(2-ethylammonioethylimino)methyl]phenolate; L² = 2-bromo-4-chloro-6-(isopropyliminomethyl)phenolate), have been prepared and characterized by elemental analyses, infrared and UV-Vis spectroscopy, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408962 (I), 1408961 (II)). Complex I crystallizes in the triclinic space group \(P\overline 1\) with unit cell dimensions a = 9.859(1), b = 13.015(2), c = 19.817(3) Å, α = 73.591(2)°, β = 76.032(2)°, γ = 82.966(2)°, V = 2363.0(5) ų, Z = 4, R ₁ = 0.0925, and wR ₂ = 0.2257. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.6387(7), b = 22.307(2), c = 21.443(2) Å, β = 96.216(3)°, V = 3632.4(6) ų, Z = 8, R ₁ = 0.0651, and wR ₂ = 0.1100. The both Zn atoms in I is four-coordinated in a tetrahedral geometry by the NO donor set of the Schiff base ligand, and two Cl ligands. The Zn atom in II is in a tetrahedral geometry by two N and two O atoms from two Schiff base ligands. Crystals of the complexes are stabilized by hydrogen bonds and weak π…π interactions. Fluorescence property of the complexes have been determined.     

Synthesis,X-ray crystal structures,and antibacterial activities of Schiff base nickel(II) complexes with similar tetradentate Schiff bases

Two new mononuclear complexes, [NiL¹] · CH₃OH (I) and [NiL²] (II), have been prepared from the tetradentate Schiff bases N,N'-bis(5-methylsalicylidene)ethylenediamine (H₂L¹) and N,N'-bis(5-methylsalicylidene)- o-phenylenediamine (H₂L₂), respectively. The complexes have been characterized by physico-chemical and spectroscopic methods, as well as single-crystal X-ray determination (CIF files nos. 1428969 (I), 1428968 (II)). Complex I crystallizes in the triclinic space group P1 with a = 6.7387(14), b = 10.7010(17), c = 12.681(2) Å, α = 87.059(2)°, β = 88.828(2)°, γ = 89.901(2)°, V = 913.0(3) ų, Z = 2. Complex II crystallizes in the monoclinic space group P2₁/n with a = 12.1437(11), b = 8.0537(8), c = 18.4545(18) Å, β = 105.088(2)°, V = 1742.7(3) ų, Z = 4. The nickel atoms in the complexes are coordinated by two phenolate O and two imine N atoms of the tetradentate Schiff base ligands, forming square planar coordination. The complexes and the Schiff base compounds 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.     

Synthesis,characterization, and crystal structures of two Schiff base zinc(II) complexes with urease inhibitory activities

Two Schiff base zinc(II) complexes, [ZnBr₂L¹] · 2CH₃OH (I) (I) and [ZnBr₂L²] (II), where L¹ is 4-chloro-2-[(2-piperazin-1-ylethylimino)methyl]phenol and L² is 4-chloro-2-[(3-diethylaminopropylimino)methyl]phenol were synthesized and structurally characterized. The crystal of I is monoclinic: space group P2₁/c, a = 9.831(3), b = 18.680(6), c = 11.879(4) Å, β = 94.660(6)°, V = 2174.3(11) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.2310(14), b = 16.037(3), c = 15.856(3), β = 90.01(3)°, V = 1838.7(6) 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 bromide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.     

Synthesis and crystal structures of cobalt(III) and zinc(II) complexes with Schiff bases

Two new cobalt(III) and zinc(II) complexes, [Co(L¹)₂ (H₂O)] · ClO₄ (I) and [Ni(L²)₂ (H₂O)₂] · 2ClO₄ (II), where L¹ is the deprotonated form of 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenol, and L² is the zwitterionic form of 2-[(2-isopropylaminoethylimino)methyl]-5-methoxyphenol, were synthesized and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 11.1512(4), b = 28.2424(11), c = 10.9655(4) Å, β = 95.746(2)°, V = 3436.1(2) ų, Z = 4. The crystal of II is triclinic: space group P2₁/c, a = 8.1441(2), b = 10.4531(3), c = 10.8849(3) Å, α = 84.0240(10)°, β = 76.9800(10)°, γ = 74.2280(10)°, V = 867.92(4) ų, Z = 1. Complex I consists of a mononuclear cobalt(III) complex cation and a perchlorate anion. Complex II consists of a crystallographic centrosymmetric mononuclear nickel(II) complex cation and two perchlorate anions. Each metal atom in the complexes is in an octahedral coordination.     

Syntheses,characterization, and crystal structures of two dinuclear nickel(II) and copper(II) complexes with Schiff bases

The phenolic azide bridged dinuclear nickel(II) complex, [Ni₂(L¹)₂(N₃)(H₂O)(μ_1,1-N₃)] · EtOH (I), and the thiocyanate bridged dinuclear copper(II) complex, [Cu₂(L²)₂(μ_1,1-NCS)₂] (II), where L¹ and L² are the deprotonated forms of 2-mothoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol and 2,4-dichloro-6-[(2-methylaminoethylimino)methyl]phenol, respectively, were synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 12.172(1), b = 20.953(1), c = 29.779(2) Å, V = 7594.8(9) ų, Z = 8. The crystal of II is monoclinic: space group P2₁/n, a = 8.7615(11), b = 19.672(2), c = 16.568(2) Å, β = 99.449(2)°, V = 2816.9(6) ų, Z = 4. The Ni atoms in I are in octahedral coordinations, and the Cu atoms in II are in square-pyramidal coordinations.     

Synthesis and crystal structures of the zinc(II) complexes with a tridentate Schiff base (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine

Two new isostructural zinc(II) complexes, [ZnCl₂(L)] (I) and [ZnBr₂(L)] (II), derived from the Schiff base ligand (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine (L), have been prepared and characterized by physicochemical methods and single-crystal X-ray crystallography. The crystal of I is monoclinic: space group P2₁/c, a = 11.699(3) Å, b = 8.460(2) Å, c = 14.766(3) Å, β = 99.686(3)°, V = 1440.6(6) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 8.166(2) Å, b = 15.153(3) Å, c = 11.966(2) Å, β = 96.964(2)°, V = 1469.7(5) ų, Z = 4. The geometry of the pentacoordinated zinc atoms in both complexes is best described as a square pyramid.     

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,crystal structures,and antibacterial activities of Schiff base zinc(II) complexes [Zn(L<Superscript>1</Superscript>)<Subscript>2</Subscript>] and [Zn(L<Superscript>2</Superscript>)<Subscript>2</Subscript>]

The reaction of cyclopentylamine with 2-hydroxy-1-naphthaldehyde and 5-nitrosalicylaldehyde, respectively, in methanol affords two new Schiff bases, 1-(cyclopentyliminomethyl)naphthalen-2-ol (HL¹) and 4-nitro-2-(cyclopentyliminomethyl)phenol (HL²). Two new zinc(II) complexes, [Zn(L¹)₂] (I) and [Zn(L²)₂] (II), derived from the Schiff bases, have been prepared and characterized by single-crystal X-ray diffraction, FT-IR, and elemental analysis. Complex I crystallizes in the monoclinic space group P2₁/c with a = 17.834(4), b = 14.738(3), c = 9.868(2) Å, β = 91.20(3)°, V = 2593.1(9) ų, Z = 4. Complex II crystallizes in the triclinic space group P \(\bar 1\) with a = 10.206(1), b = 10.502(1), c = 12.554(1) Å, α = 66.771(2)°, β = 78.133(2)°, γ = 76.292(2)°, V = 1191.8(1) ų, Z = 2. The Zn atom in each complex is coordinated by two N and two O atoms from two Schiff base ligands, forming a tetrahedral geometry. The Schiff bases and the complexes were assayed for antibacterial activities.     

Synthesis and crystal structures of binuclear complexes of cobalt(II) and cadmium(II) diisobutyldithiophosphinates with hexamethylenetetramine

Heteroligand complexes [Co₂(HMTA)(iso-Bu₂PS₂)₄] (I) (μ_eff = 4.67 μB) and [Cd₂(HMTA)(iso-Bu₂PS₂)₄] (II) have been synthesized. Single crystals of compounds I and II have been obtained. The crystals are monoclinic: a = 32.622(2) Å, b = 9.4891(6) Å, c = 21.7570(13) Å, β = 125.774(1)^o, V = 5464.3(6) Å,³, Z = 4, ρ_calcd = 1.331 g/cm³ for I; a = 34.6092(7) Å, b = 9.5595(2) Å, c = 22.3473(5) Å, β = 127.144(1)^o, V = 5893.5(2) Å, Z = 4, ρ_calcd = 1.355 g/cm³ for II; space group for both complexes C2/c. Structures I and II are based on discrete binuclear molecules. The coordination polyhedra of the Co and Cd atoms are distorted tetragonal pyramids NS₄, with the bases formed by four S atoms of two bidentate chelating ligand iso-Bu₂PS ₂ ^? and the axial vertices occupied by N atoms of bidentate bridging HMTA ligand. The character of interaction of the molecules in structures I and II is considered.     

Synthesis and crystal structure of zinc(II) and manganese(II) complexes of 2-(diphenylacetyl)indandione-1,3

Zinc(II) and manganese(II) complexes of 2-(diphenylacetyl)indandione-1,3 (HL) were synthesized. Crystals of [M(DMSO)₂L₂] · CHCl₃, where M= Zn^(II) (I) and Mn^(II) (II), obtained from chloroform plus dimethyl sulfoxide (DMSO) mixture were found to be isostructural based on the similarity of their unit cell parameters and unit cell volumes. The crystals are triclinic, Z = 2, space group P \(\bar 1\); a = 10.422(1) Å, b = 11.929(1) Å, c = 20.429(1) Å, α = 73.616(1)°, β = 85.095(1)°, γ = 77.586(1)° for complex I; a = 10.436(1) Å, b = 12.297(1) Å, c = 19.924(2) Å, α = 78.138(2)°, β = 87.625(2)°, γ = 82.048(2)° for complex II. X-ray structural analysis of complex I was carried out. For complex II, the structure was not refined because all of its atoms are each disordered over three to five positions. The two DMSO molecules in complex I coordinate the central metal atoms in the monodentate mode via their donor oxygen atoms to occupy an axial position and an equatorial position in an octahedral polyhedron. The other four positions are occupied by the four oxygen atoms of the two deprotonated ligands L^? coordinated in the bidentate-cyclic mode. The outer sphere of complex I contains the solvating chloroform molecule.     

Crystal structure of adducts of copper(II) acetylacetonate and hexafluoroacetylacetonate with 4-aminopyridine

Single crystal X-ray diffraction is used to investigate two synthesized β-diketonate complexes of copper(II) with aminopyridine: Cu(4-NH₂Py)(aa)₂ (I) and Cu(4-NH₂Py)(hfa)₂ (II). The crystals of I and II have a monoclinic system; the unit cell parameters of I are: P2₁/n space group, a = 8.2921(3) Å, b = 14.7243(5) Å, c = 13.4970(4) Å, β = 102.426(1)°, V = 1609.32(9) ų, Z = 4; for II: C2/c space group, a = 23.5704(5) Å, b = 11.4977(2) Å, c = 16.0285(3) Å, β = 109.265(1)°, V = 4100.6(1) ų, Z = 8. The structures of I and II are molecular; they are composed of isolated molecules. The coordination polyhedron of the copper atom is formed by the O atoms of two acetylacetonate ligands (Cu-O 1.940(2)–2.171(2) I and the O atoms of two hexafluoroacetylacetonate ligands (Cu-O 1.940(2)–2.215(3) Å) in II. The molecules of 4-NH₂Py are bonded to the copper atom via the nitrogen atom of the aromatic ring (Cu-N 2.008(2) Å in I and Cu-N 1.978(3) Å in II). Noncoordinated amino groups join the molecules of the complexes together by means of N-H…O hydrogen bonds.     

Microwave-assisted synthesis,crystal structures,and in vitro antibacterial studies of zinc(II) and nickel(II) complexes with Schiff bases

The syntheses of a mononuclear zinc(II) complex [ZnCl(L¹)(Amp)] (I) and a mononuclear nickel(II) complex [Ni(L²)(HL²)](BF₄) · 0.5H₂O (II) (HL¹ = 4-methyl-2-[(4-methylpyridin-2-ylimino) methyl]phenol, HL² = 4-methyl-2-[(pyridin-2-ylmethylimino)methyl]phenol; Amp = 2-amino-4- methylpyridine) were prepared under microwave irradiation. The complexes were characterized by a combination of elemental analyses, and IR and electronic spectra. Their structures were further confirmed by single crystal X-ray crystallography (СIF files CCDC nos 1437737 (I), 1437738 (II)). The Zn atom in the monomeric complex I is in tetrahedral coordination. The Ni atoms in the dimeric complex II are in octahedral coordination. Crystals of the complexes are stabilized by hydrogen bonds. In order to evaluate the biological activity of the complexes, in vitro antibacterial against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa was assayed. The complexes have strong activity against Bacillus subtilis.     

Synthesis,characterization, crystal structures,and antimicrobial activity of cobalt(II) and iron(III) complexes derived from N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide

A new cobalt(II,III) complex, [Co^IIIL₂]₂[Co ₂ ^II (HL)₂(OH₂)₂(CH₃OH)₂] ? 2H₂O (I) and a new iron(III) complex, [Fe^III(HL)₂](NO₃) (II), where L^2– and HL^– are the dianionic and monoanionic form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, respectively, have been prepared and characterized by elemental analyses, infrared and UV-Vis spectroscopy and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1417971 (I), 1417979 (II)). Complex I crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 16.1665(9), b = 14.5692(8), c = 19.086(1) Å, β = 96.347(1)°, V = 4467.9(4) ų, Z = 2, R ₁ = 0.0521, and wR ₂ = 0.1411. Complex II crystallizes in the orthorhombic space group Pbcn with unit cell dimensions a = 12.475(1), b = 12.202(1), c = 18.859(2) Å, V = 2870.8(4) ų, Z = 4, R ₁ = 0.0796, and wR ₂ = 0.1981. The metal atoms in the complexes are in octahedral coordination. Crystals of the complexes are stabilized by hydrogen bonds. The efficiency of the aroylhydrazone and the two complexes was evaluated against B. subtilis, S. aureus, E. coli, P. fluorescence, C. albicans and A. niger, with the complexes demonstrating enhanced activity relatively to the free ligand.     

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.     

Synthesis and crystal structures of (2.2.2-cryptand)rubidium chloride and bromide hydrates

Two complexes, (2.2.2-cryptand)rubidium chloride and bromide hydrates [Rb(Crypt-222]Hal · 3.5H₂O (Hal = Cl (I) and Br (II)), are synthesized. The structures of isomorphic crystals of compounds I and II are studied by X-ray diffraction analysis. The crystals are trigonal: space group P \(\overline 3 \), Z = 2; I: a = 11.810 Å, c = 11.302 Å; II: a = 11.890 Å, c = 11.402 Å. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.060 (I) and 0.077 (II) for 2650 (I) and 2700 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). In crystals of complexes I and II, the [Rb(Crypt-222)]⁺ cation of the host-guest type lies on the crystallographic axis 3 and has the approximate symmetry D ₃. In complexes I and II, the coordination polyhedron of the Rb⁺ cation is a two-base-centered trigonal prism somewhat distorted to an antiprism. The crystals of compounds I and II contain H-bonded disordered cubes of the water molecules and Cl^? or Br^? anions.     

Synthesis,crystal structure,and antibacterial activity of oxovanadium(V) complexes derived from <Emphasis Type="Italic">N</Emphasis>'-[1-(5-fluoro-2-hydroxyphenyl)methylidene]nicotinohydrazide and <Emphasis Type="Italic">N</Emphasis>'-(5-fluoro-2-hydroxybenzylidene)-2-hydroxynaphthylhydrazide

Two new oxovanadium(V) complexes, [VOL¹(OCH₃)(CH₃OH)] (I) and [VOL²(OCH₃)] (II), where L¹ and L² are the di-anionic form of N'-[1-(5-fluoro-2-hydroxyphenyl)methylidene]nicotinohydrazide and N'-(5-fluoro-2-hydroxybenzylidene)-2-hydroxynaphthylhydrazide, respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination (CIF files CCDC nos. 891852 (I), 891853 (II)). The crystal of I is monoclinic: space group P2₁/c, a = 8.061(1), b = 15.293(2), c = 13.471(2) Å, ß = 92.595(2)°, V = 1658.8(4) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.4454(9), b = 8.0833(9), c = 28.906(2) Å, ß = 92.644(2)°, V = 1737.8(3) ų, Z = 4. The V atom in I is in an octahedral coordination, and that in II is in a square-pyramidal coordination. The antibacterial activity of the compounds against various bacteria was assayed.     

Synthesis and crystal structures of two zinc(II) complexes derived from 4-bromo-2-(cyclopentyliminomethyl)phenol with different solvents

Two new mononuclear zinc(II) complexes, [ZnL₂] (I) and [ZnL₂] · 2MeOH (II) (HL = 4-bromo-2-(cyclopentyliminomethyl)phenol), were synthesized by the reaction of the Schiff base HL with zinc acetate in ethanol and methanol solutions, respectively. Both complexes were characterized by elemental analyses and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 14.711(3), b = 13.223(3), c = 24.870(5) Å, V = 4837.8(18) ų, Z = 8. The crystal of II is monoclinic: space group C2/c, a = 20.581(5), b = 10.660(3), c = 15.428(4) Å, β = 119.919(3)°, V = 2933.7(13) ų, Z = 4. The Zn atom in each complex is four-coordinated by two imine N and two phenolic O atoms, forming a tetrahedral geometry. Complex II possesses crystallographic two-fold rotation axis symmetry.     

Hexafluorosilicates of cobalt(II) complexes with dimethylsulfoxide and dimethylformamide

New double complexes [Co(DMSO)₆][SiF₆] ? 2H₂O (I) and [Co(DMF)₃(H₂O)₃][SiF₆] ? DMF (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals of complex I belong to the tetragonal symmetry system, space group R3?, Z = 3, a = 11.8232(3) Å, c = 18.4699(5) Å, V = 2235.97(10) ų, ρ_calc = 1.573 g/cm³. Crystals of complex II are triclinic, space group P1?, Z = 2, a = 8.6264(4) Å, b = 10.1419(4) Å, c = 13.9657(6) Å, α = 100.847(2)°, β = 98.549(2)°, γ = 93.479(2)°, V = 1181.71(9) ų, ρ_calc = 1.539 g/cm³.     

Synthesis,crystal structures,and catalytic property of dioxomolybdenum(VI) complexes with hydrazone ligands derived from 3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butylsalicylaldehyde

Two new dioxomolybdenum(VI) complexes, [MoO₂L¹(MeOH)] (I) and [MoO₂L²] (II), where L¹ and L² are the anionic forms of N'-(2-hydroxy-3,5-di-tert-butylbenzylidene)-4-methoxybenzohydrazide and 2-amino-N'-(2-hydroxy-3,5-di-tert-butylbenzylidene)benzohydrazide, respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination (CF files CCDC nos. 1448089 (I), 1487063 (II)). The crystal of I is monoclinic: space group P21/n, a = 7.353(1), b = 24.758(3), c = 13.891(2) Å, β = 101.013(2)°, V = 2482.3(6) Å3, Z = 4, R ₁ = 0.0848, wR ₂ = 0.2050. The crystal of II is monoclinic: space group P2₁/c, a = 6.752(1), b = 16.947(1), c = 19.510(1) Å, β = 96.891(2)°, V = 2216.5(4) Å3, Z = 4, R ₁ = 0.0670, wR ₂ = 0.1638. The Mo atom in complex I is in octahedral coordination, with three donor atoms of the hydrazone ligand, two oxo groups, and one methanol O atom. The Mo atom in complex II is in square pyramidal coordination, with three donor atoms of the hydrazone ligand, and two oxo groups. The complexes have interesting catalytic properties for sulfoxidation reactions.     

Synthesis and crystal structures of Schiff base oxovanadium(V) complexes [VO(Bhm)(OCH<Subscript>3</Subscript>)(CH<Subscript>3</Subscript>OH)] and [VO<Subscript>2</Subscript>(Bpp)]

Compound [VO(acac)₂] reacts with the Schiff bases N′-(5-bromo-2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide (H₂Bhm) and 4-bromo-2-[(2-piperidin-1-ylethylimino)methyl]phenol (HBpp) in absolute methanol to give the oxovanadium(V) complexes [VO(Bhm)(OCH₃)(CH₃OH)] (I) and [VO₂(Bpp)] (II), respectively. Both complexes were characterized by elemental analysis, IR spectra, and single-crystal X-ray determination. The crystal of I crystallizes in the triclinic space group \(P\bar 1\) with a = 7.625(2), b = 11.240(3), c = 12.156(4) Å, α = 77.404(5)°, β = 75.770(4)°, γ = 79.922(5)°, V = 977.4(5) ų, Z = 2. The crystal of II crystallizes in the monoclinic space group P2/c with a = 26.760(3), b = 6.655(1), c = 17.570(2) Å, β = 100.335(2)°, V = 3078.2(7) ų, Z = 8. The V atom in I is in an octahedral coordination, and those in II are intervenient between square pyramidal and trigonal bipyramidal coordination.