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 N′-(3-ethoxy-2-hydroxybenzylidene)-3-methylbenzohydrazide and its dioxomolybdenum(VI) complex

A new hydrazone N′-(3-ethoxy-2-hydroxybenzylidene)-3-methylbenzohydrazide (H₂L), derived from condensation of 3-ethoxysalicylaldehyde with 3-methylbenzohydrazide, and its dioxomolybdenum(VI) complex [MoO₂L(CH₃OH)], have been prepared and characterized by physico-chemical methods and single crystal X-ray diffraction. The hydrazone coordinates to Mo through the phenolate O, imine N, and enolic O. The Mo is six-coordinate in a distorted octahedral geometry, with the three donors of L and one oxo defining the equatorial plane, and with one methanol and another oxo occupying the axial positions. The bond values especially for those related to the donors in the complex are different from those in H₂L.     

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 catalytic property of oxovanadium(V) complex derived from N′-(2-hydroxynaphthylidene)-4-chlorobenzohydrazide and 1,10-phenanthroline

A new oxovanadium(V) complex, [VO(L)(Phen)], where L is the dianionic form of N′-(2-hydroxynaphthylidene)-4-chlorobenzohydrazide, Phen is 1,10-phenanthroline, has been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination. The crystal of the complex is monoclinic: space group P2₁/c, a = 11.2376(8), b = 13.3068(10), c = 17.5593(11) Å, β = 106.806(2)°, V = 2513.6(3) ų, Z = 4. The V atom in the complex is in octahedral coordination, with the phenolate O, imine N, and enolate O atoms of L and one N atom of Phen define the equatorial plane, and with the other N atom of Phen and one oxo O atom located at the axial positions. The complex is a good catalyst for the oxidation of thioanisole to the corresponding sulfoxide by cumene hydroperoxide.     

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.     

New vanadium and zinc complexes with schiff base ligand N,N′-bis(3-ethoxy-2-hydroxybenzylidene)ethylenediamine: Synthesis,structures, and biochemical properties

The Schiff base ligand N,N′-bis(3-ethoxy-2-hydroxybenzylidene)ethylenediamine (H₂L) reacting with vanadyl acetylacetonate and zinc chloride, respectively, in methanol gave the complexes [VOL] · H₂O (I) and [ZnL(OH₂)] (II). Both complexes were characterized by elemental analyses and IR spectroscopic method in the solid state. Single crystal X-ray analysis was performed, which reveals that both of them are mononuclear complexes. Complex I crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 9.4387(7), b = 16.996(1), c = 12.758(1) Å, β = 98.269(2)°, V = 2025.4(3) ų, Z = 4, R ₁ = 0.0365, and wR ₂ = 0.0946. Complex II crystallizes in the tetragonal space group $P\overline {42} _{1m} $ with unit cell dimensions a = b = 22.0489(8), c = 4.9846(4) Å, V = 2423.3(2) ų, Z = 4, R ₁ = 0.0890, and wR ₂ = 0.2278. The V atom in I and the Zn atom in II are in square pyramidal coordination. Anbacterial activities of the Schiff base ligand and the complexes have been studied on the strains B. subtilis, E. coli and S. aureus.     

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,crystal structures,and photophysical properties of dibromo-2-(2′-pyridyl)imidazole and its corresponding boron–fluorine complex

2-(2′-Pyridyl)imidazole L1 and its corresponding boron–fluorine complex, 1, were synthesized and their crystal structures correlated with their photophysical properties. L1 forms a rigid supramolecular network through hydrogen bonds and halogen bond in the single crystal, which induces amplified spontaneous emission in crystals; it emits rather poor fluorescence in solution and powder states. Its boron chelate 1 emits intense fluorescence in solution since boron chelate is an excellent chromophore, and it exhibits large Stokes shift (136?nm in acetonitrile), due to the charge-transfer transition from the electron-donating π system to the electron-accepting boron moiety. Interestingly, 1 is also highly fluorescent in amorphous powder and crystal states; C–C rotation between pyridyl and imidazole groups is inhibited by the formation of a five-member ring containing BF₂, and the formation of intermolecular non-covalent bonds is the key factor. Solid emission with large Stokes shift makes it a valuable chromophore for synthesis of functional materials.     

Synthesis and X-ray structural characterization of dioxomolybdenum(VI) complexes with N′-(5-chloro-2-hydroxybenzylidene)-4-methylbenzohydrazide and N′-(2-hydroxybenzylidene)-4-methylbenzohydrazide

Two new dioxomolybdenum(VI) complexes, [MoO₂(ClHm)(CH₃OH)] (I) and [MoO₂(Hm)(CH₃OH)] (II) with the hydrazone ligands H₂ClHm and H₂Hm derived from 4-methylbenzohy-drazide with 5-chlorosalicylaldehyde and salicylaldehyde, respectively, have been synthesized and structurally characterized by physicochemical methods and single-crystal X-ray determination. The crystal of I crystallizes in the triclinic space group \(P\bar 1\), with a = 7.839(2), b = 9.656(3), c = 11.548(4) Å α = 88.885(3)°, β = 87.454(3)°, γ = 88.996(3)°, V = 873.0(5) ų, Z = 2, R ₁ = 0.0292, wR ₂ = 0.0685, S = 1.092. The crystal of II crystallizes in the triclinic space group \(P\bar 1\), with a = 7.780(2), b = 10.584(3), c = 10.628(3) Å, α = 91.462(3)°, β = 104.818(3)°, γ = 103.288(3)°, V = 820.1(4) ų, Z = 2, R ₁ = 0.0403, wR ₂ = 0.0784, S = 1.065. An X-ray analysis indicates that the structures of both complexes are similar to each other. The molybdenum atom in each complex is in an octahedral coordination environment constructed by two oxo groups, an NO₂ donor set of the hydrazone ligand, and one methanol O atom.     

Syntheses,structures, and luminescent properties of lanthanide complexes with N,N′-bis(p-methoxyphenyl)-3-oxapentanediamide

An amide-type acyclic polyether, N,N′-bis(p-methoxyphenyl)-3-oxapentanediamide (L), and its three lanthanide coordination compounds, [Ln(NO₃)(L)₂(H₂O)₂]?·?(NO₃)₂ [Ln?=?Pr (1), Nd (2), and Dy (3)], have been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and X-ray diffraction. Single crystal X-ray structure analyses reveal that 1 and 2 have the same structure and crystallize in the monoclinic crystal system with C2/c space group. The coordination geometry around the central atom is a distorted bicapped square antiprism. Extensive intermolecular hydrogen bonds in 1 and 2 result in 3-D supramolecular networks. Complex 3 exhibits luminescence in the visible region upon excitation with UV-rays.     

A novel binuclear uranyl(VI) complex of bis(N,N′-3-carboxysalicylidene)-1,3-diaminopropan-2-ol: Synthesis, structure, and properties

A binuclear uranyl(VI) Schiff base complex of general formula [(UO₂)₂(H₂L)(OH)(DMSO)₂] · 2DMSO (I) (H₂L = trianion of bis(N,N??-3-carboxysalicylidene)-1,3-diaminopropan-2-ol) was synthesized and studied by ¹H NMR, UV-Vis, IR spectroscopy and X-ray crystallography.     

Spectrophotometric determination of molybdenum(V) by extraction of its 2-(2′-furyl)-3-hydroxychromone complex

A simple method is described for the rapid spectrophotometric determination of molybedenum in synthetic and industrial samples containing 0.1-5% Mo. Molybdenum is reduced with ascorbic acid at room temperature in 1 mol dm^–3 H₂SO₄ and extracted with chloroform after adding 2-(2-furyl)-3-hydroxychromone (FHC). The yellow colour of the 1 2 Mo-FHC complex is measured at 414 nm against a reagent blank. Beer's law is obeyed over the range 0-2.7 g Mo cm^–3 of solvent phase. The molar absorptivity and Sandell's sensitivity are 5.18 × 10⁴ dm³ mol^–1 cm^–1 and 0.0018 g Mo cm^–2, respectively. Relative standard deviations are 0.2% for solutions and 0.5–1.5% for solid samples. Interference from tungsten and tin is removed by adding citrate and EDTA, respectively, while niobium and tantalum are masked by fluoride. Many elements such as V, Fe, Ti, U, Mn, Cr, Co, Ni, Re, Ru, Pt, Rh, Se, Au, Bi, Zr, Th, Ce, As and Al do not interfere even in large amounts, but antimony always interferes. Among the anions and complexing agents, only thiocyanate interferes seriously.     

Syntheses and crystal structures of oxovanadium(V) complexes derived from N′-[1-(2-hydroxynaphthyl)ethylidene]-4-nitrobenzohydrazide and 2-hydroxy-N′-[1-(2-hydroxynaphthyl)ethylidene]benzohydrazide

Reactions of bis(acetylacetonato)oxovanadium(IV) with N??-[1-(2-hydroxynaphthyl)ethylidene]-4-nitrobenzohydrazide (H₂HNB) and 2-hydroxy-N??-[1-(2-hydroxynaphthyl)ethylidene]benzohydrazide (H₂HHB), respectively, product two oxovanadium(V) species with the formulas [VO(OMe)(HNB)]₂ (I) and [VO(OMe)(HHB)] (II). The complexes I and II have been characterized by elemental analysis, IR spectra, and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n, a = 8.208(2), b = 14.528(3), c = 16.418(3) ?, ?? = 97.887(3)°, V = 1939.3(7) ?³, Z = 2. The crystal of II is triclinic: space group P $P\bar 1$ a = 8.334(2), b = 10.236(2), c = 11.337(2) ?, ?? = 80.91(3)°, ?? = 75.41(3)°, ?? = 75.63(3)°, V = 902.0(3) ?³, Z = 2. Complex I is a methoxide-bridged dimeric oxovanadium(V) complex, and complex II is a mononuclear oxovanadium(V) complex. The V atom in I is in an octahedral coordination, and that in II is in a square pyramidal coordination.     

Solvent-free synthesis and crystal structures of s-cis and s-trans N,N′-bis(2-hydroxycyclohexyl)ethane-1,2-diamine

The symmetrical amino alcohol synthesis via ring opening of cyclohexene oxide with ethylendiamine is illustrated by synthesis and characterization of β-amino alcohols s-cis-(SSSS)-cy₂en (1) and s-trans-(SSRR)-cy₂en (2) (cy₂en = N,N′-bis(2-hydroxycyclohexyl)ethane-1,2-diamine) in one step and with high yield. The reaction was carried out in a microwave reactor under solvent-free conditions. These products were characterized by IR and Raman spectroscopy, elemental analysis, thermal methods (TGA, DTG and DTA), mass spectrometry and ¹H and ¹³C NMR spectroscopy. The crystal structures of 1 and 2 were determined by single crystal X-ray structural analysis, followed by DFT calculations. Intramolecular hydrogen bond was observed in 1 with C ₂ symmetry, but not in 2 with C _i symmetry. The nature of intramolecular hydrogen bond in 1 has been investigated by AIM and NBO analyses. The molecules in 1 are linked into an infinite chain along the [001] direction, giving rise to R ₄ ⁴ (8) graph-set motif, while the molecules in 2 are linked into a 2D network in the bc plane, giving rise to R ₂ ² (10) and R ₃ ³ (12) motifs. The protonation equilibria of 1 and 2 have been studied by pH-potentiometry, with pK ₁ 9.01 and pK ₂ 5.50 determined for 1 and pK ₁ 8.58 and pK ₂ 5.26 determined for 2.     

Synthesis,crystal structures and photoluminescence of 7-(N,N′-diethylamino)-3-phenylcoumarin derivatives

Two new coumarin derivatives, 7-(N,N′-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N′-diethylamino)-3-(4-bromophenyl)-coumarin, were synthesized successfully. Their structures were verified by single crystal X-ray crystallography. The UV–vis absorption and fluorescence of the compounds were discussed. The compounds exhibit strong blue emission under ultraviolet light excitation. The molecular structures, the lowest energy transitions and the UV–vis spectra of 7-(N,N′-diethylamino)-3-(4-hydroxyphenyl)-coumarin and 7-(N,N′-diethylamino)-3-(4-bromophenyl)-coumarin have been studied with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at B3LYP/6-31G(d) level.     

Characterization and crystal structures of solvated N′-(4-hydroxy-3-nitrobenzylidene)-3-methylbenzohydrazide and N′-(4-dimethyl-aminobenzylidene)-3-methylbenzohydrazide

Two new solvated benzohydrazone derivatives N′-(4-hydroxy-3-nitrobenzylidene)-3-methylbenzohydrazide-methanol-water (2/1/1) 2(C₁₅H₁₃N₃O₄)·CH₃OH·H₂O (1) and N′-(4-dimethylamino-benzylidene)-3-methylbenzohydrazide methanol monosolvate C₁₇H₁₉N₃O·CH₃OH (2) are prepared and characterized by elemental analysis, ¹H and ¹³C NMR, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 17.084(2) Å, b = 12.706(1) Å, c = 15.412(1) Å, β = 113.207(1)°, V = 3074.1(4) ų, Z = 4, R ₁ = 0.0567, and wR ₂ = 0.1209. Compound 2 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 15.058(1) Å, b = 6.658(1) Å, c = 17.211(2) Å, β = 94.189(2)°, V = 1720.8(3) ų, Z = 4, R ₁ = 0.0611, and wR ₂ = 0.1594. X-ray diffraction indicates that the asymmetric unit of 1 contains two independent benzohydrazone molecules, one methanol and one water molecules. The asymmetric unit of 2 contains one benzohydrazone molecule and one methanol molecule. Benzohydrazone molecules of the compounds display trans configurations with respect to the C=N double bonds. The crystal structures of the compounds are stabilized by hydrogen bonds and weak π...π interactions.     

N,N′-dipyridoxyl(ethylenediamine) schiff-base ligand and its square-pyramidal copper(II) complex: Synthesis, experimental and theoretical characterization

A new tetradentate N,N??-dipyridoxyl(1,2-ethylenediamine) [=H₂ES] Schiff-base ligand and its Cu(II) salen complex [Cu(ES)(H₂O)] are synthesized and characterized by IR, UV-Vis, ¹H NMR, mass spectrometry, and elemental analysis. Their optimized geometries and theoretical vibrational frequencies are computed by using the density functional theory method where the B3LYP functional was used. Also, the ¹H NMR chemical shifts of the H₂ES ligand are calculated at the same computational level. In the optimized structure of the free ligand, two pyridine rings are not in the same plane. In the structure of the complex, the Schiff-base ligand acts as a dianionic tetradentate ligand in the N, N, O^?, O^? manner, so that the coordinating atoms occupy equatorial positions. The H₂O ligand occupies the axial position of the squarepyramidal complex. The calculated results are consistent with the experimental ones, confirming the suitability of the optimized structures for the H₂ES ligand and its Cu(II) complex.     

One-pot synthesis and fungicidal activity of 2-(1,5,3-dithiazepan-3-yl)ethanol and N,N′-bis(2-hydroxyethyl)tetrathiadiazacycloalkanes

Synthesis of 2-(1,5,3-dithiazepan-3-yl)ethanol and N,N′-bis(2-hydroxyethyl)tetrathiadiazacycloalkanes was performed by multicomponent condensation of monoethanolamine with formaldehyde and SH-acids (1,2-ethane, 1,3-propane-, 1,4-butane-, 1,5-pentane-, and 1,6-hexanedithiols). The resulting S,N-containing heterocycles and macrocycles possess fungicidal properties relative to microscopic fungi, plant pathogens.     

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) bis -( O,O ′-alkylene dithiophosphates): synthesis and characterization

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) alkylene dithiophosphates, (M = Nb(V) or Ta(V); G =–CHMeCHMe–,–CMe₂CMe₂–,–CH₂CMe₂CH₂–,–CH₂CEt₂CH₂–or–CMe₂CH₂CHMe–and X = Cl or OPrⁱ) have been synthesized by reaction of metal(V) chloride, MCl₅, or triisopropoxymetal(V) dichloride, (PrⁱO)₃MCl₂, with the sodium salts of O,O′-alkylene dithiophosphoric acids, in 1 : 2 molar ratio in THF under anhydrous conditions. These pink-purple or light-yellow compounds are viscous, semi-solid or solid, hydrolyzable and soluble in common organic solvents. These compounds have been characterized by elemental analyses, molecular weight determinations and spectral studies like IR and heteronuclear NMR (¹H, ¹³C and ³¹P), which indicated a bidentate mode of chelation of dithio ligands, leading to a pentagonal bipyramidal geometry around the niobium(V) or tantalum(V) centers.