Electronic and vibrational studies of copper(II) complexes of 1-phenyl-3-methyl-4-acylpyrazolones-5

The interaction between Cu(II) and 1-pheny]-3-methyl-4-acylpyrazolones in aqueous medium has been investigated. The complexes were isolated and characterized using electronic and vibrational spectral measurments. Bathochromic shifts were observed for the complexes in the UV and infrared (IR) spectral regions. Analysis of the spectral properties of the complexes reveal that the stability of the

bond of the COCu bonding system decreases while that of the CuO bond in the same system increases as the carbon chain of the 4-acyl substituent increases. The complexes have μ_eff values within the range of 1.75–1.82 B.M.     

Formation and structure of 1-Amino-4-methyl-4-(4-methyl-5-phenyl-1H-pyrazol-3-ylamino)-3-phenyl-4,5-dihydro-1H-pyrazol-5-one

The title compound 3 was obtained during the rearrangement of isoxazol-5-yl hydrazine 1 to 1-aminopyrazolone 2 at 115°. X-ray analysis of the corresponding benzylidene derivative allowed us to achieve the structure assignment.     

4-双(1-苯基-3-甲基-4-吡唑啉-5-酮)甲烷的晶体结构

杂环化合物1 苯基 3 甲基 4 吡唑啉 5 酮(ＨＰＭＰ)为β 二酮,不仅可用作金属离子的萃取剂,还可用于核磁共振的位移试剂,也可用于激光、催化、生化、医学等领域[1-4]。我们从ＰＭＰ出发,合成了它的Ｃｏ(Ⅱ),Ｎｉ(Ⅱ),Ｃｕ(Ⅱ)和Ｚｎ(Ⅱ)的络合物[5,6]。利用单晶Ｘ 射线衍射分析方法报道了标题化合物的晶体结构。1　实验部分在合成ＰＭＰ席夫碱化合物的过程中,得到标题化合物的单晶体。元素分析结果(括号内为计算值)Ｃ%:69 87(69 98),Ｈ%:5 62(5 59),Ｎ:15 61(15 55)。红外光谱(ＫＢｒ):1645和1637ｃｍ-1的强吸收峰归属为羰基的伸缩振动,…     

Polymeric copper(II) complexes with 4-formyl-3-methyl-1-phenylpyrazol-5-one hetarylhydrazones: Synthesis and crystal structures

4-Formyl-3-methyl-1-phenylpyrazol-5-one quinolin-2-yl-(H₂L¹) and benzothiazol-2-ylhydrazones (H₂L²) were synthesized and studied. Quantum-chemical modeling of possible tautomers of the hydrazones was performed. Copper(II) complexes of the general formula [Cu(HL)(ROH)]Y (R = CH₃, C₂H₅; Y=NO₃, ClO₄) were obtained and examined by IR and EPR spectroscopy, magnetochemistry, and X-ray diffraction. Additional coordination through the N atom of the pyrazole ring enables the complex molecules to form zigzag polymer chains linked by intermolecular hydrogen bonds.     

Studies on extraction of copper(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of Cu(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (HA), in different organic solvents has been studied. The extraction mechanism of Cu(II) and the composition of the extracted species has been determined. Cu(II) was extracted as CuA₂, or in the presence of TOPO, as CuA₂TOPO. The extraction constants do not change regularly with increasing the length of acyl chain in the 1-phenyl-3-methyl-4-acyl-5-pyrazolone derivatives. The effect of the temperature on the extraction of Cu(II) has also been investigated.     

Four-coordinate nickel(II) and copper(II) complexes of 7-amino-4-methyl-5-aza-3-heptene-2-one

Summary The condensation of acetylacetone with ethylenediamine yields 7-amino-4-methyl-5-aza-3-heptene-2-one (AEH). This terdentate (N₂O) Schiff base forms various types of ternary complexes, depending on the nature of the second ligand. Examples of five- and six-coordination have been previously reported. The present paper points to the possibility of preparing a less common type of complex,i.e. [M^II(AE)Py]⁺ (M=Ni or Cu) in which the use of a monodentate ligand (pyridine) favours a square planar geometry.     

Spectroscopic studies of manganese(II) and zinc(II) complexes of 1-phenyl-3-methyl-4-acylpyrazolone-5

Mn(II) and Zn(II) complexes of a series of 4-acyl derivatives of 1-phenyl-3-methylpyrazolone-5 have been synthesized. Characterization was by elemental analyses, UV, IR and ¹H NMR analyses. The chelates were found to conform to a general molecular formula ML₂·xCH₃CH₂OH·yH₂O where M = Mn, Zn; L is the acylpyrazolone-5 anion; x = 0, 1 or 2; and y = 0, 1 or 2. Spectral analyses showed that the adducts associated with the complexes have no effect on the bathochromic shifts observed in the UV and IR spectral properties of the complexes. The stability of the C

O and COM bonds does not follow any regular pattern with respect to the carbon chain of the 4-acyl substituent. The Mn(II) complexes have μ_eff values within the range of 5.3–5.6 B.M.     

Binuclear copper(II) complexes with acyldihydrazones of 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazoles

The synthesis of copper(II) binuclear complexes with acyldihydrazones of saturated carboxylic acids and 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazoles in which the coordination polyhedra are connected by polymethylene chains of different length (two to five units) is described. The complexes were studied by chemical and thermal analysis, IR spectroscopy, and EPR. The molecular and crystal structure of the copper(II) complex with glutaric acid and 1-(4′-chlorophenyl)-4-formyl-5-hydroxy-3-methylpyrazole acyldihydrazone (H₄L) described as [Cu₂L·2Py] · Py · 4H₂O was determined by X-ray diffraction. The crystals are orthorhombic: a = 24.789(7) Å, b = 39.319(9) Å, c = 4.6336(14) Å, space group Pnma, Z = 4. The number of symmetrically unrelated reflections is 4716, R = 0.0606, R _w = 0.1307. The central atoms are separated by a chain of eight σ bonds and are located at a distance of 8.939 Å. The copper coordination polyhedron is a square. A specific feature of the crystal structure is the stacking interaction involving chelate rings and the pyrazole ring, resulting in stacks of molecular complexes. The EPR spectrum of a solution of the complex based on the acyldihydrazone of succinic acid and 4-formyl-5-hydroxy-3-methyl-1-phenylpyrazole recorded at room temperature exhibits seven HFS lines with an intensity ratio of 1: 2: 3: 4: 3: 2: 1 and a constant of 33.3 G as a result of exchange coupling of the unpaired electrons to the two equivalent copper nuclei. An increase in the length of the polymethylene chain to 3–5 units or introduction of the para-chlorine atom into the benzene ring hampers the exchange interactions, and the EPR spectrum shows a signal of four HFS lines with a constant of 55–70 G typical of monomeric copper(II) complexes.     

Coordination compounds of dysprosium(III) with 3-methyl-1-phenyl-4-formylpyrazol-5-one diacyldihydrazones

Coordination compounds of dysprosium(III) with diacyldihydrazones of saturated dicarboxylic acids, imino-, oxo-, and thiodiacetic acids, and 3-methyl-1-phenyl-4-formylpyrazol-5-one (H₄L) are described. [Dy₂(H₂L^O)₃] · 7.5CH₃OH · 3H₂O was subjected to X-ray diffraction analysis: space group \(R\bar 3\) , a = 17.349(1) Å, c = 65.669(4) Å, Z = 6, R = 0.076, R _w = 0.243 (5301 reflections with I ≥ 2σ(I)). The complex is established to have a binuclear structure and contain dysprosium ions linked via three bridging ligands. The coordination polyhedron of the Dy atom had a three-capped trigonal prism geometry. The magnetic properties of the synthesized complexes were studied.     

Complexes of Zr(IV) and Nb(V) with 1-phenyl-3-methyl-4-benzoyl-pyrazole-5-one

The complexing of Zr(IV) and Nb(V) by 1-phenyl-3-methyl-4-benzoyl-pyrazole-5-one (HPMBzP) in various mineral acids has been studied by solvent extraction. The pyrazolone tautomers have been isolated and characterised, and the composition and structure of zirconium and niobium complexes have been established using various chemical and spectroscopic techniques.     

Synthesis, structure, electrochemical properties, cytotoxic effects and antioxidant activity of 5-amino-8-methyl-4H-benzopyran-4-one and its copper(II) complexes

The chromone derivative 5-amino-8-methyl-4H-benzopyran-4-one (ligand) (1) has been used to obtain a series of Cu(II) complexes 2-4 as potential anticancer compounds. The molecular structures of ligand 1 and its Cu(II) complex 3 have been determined by X-ray crystallography. The cytotoxicity of all obtained compounds has been evaluated on melanoma A375 cell line. The ability of compounds 1-4 to take part in redox reactions and their antioxidant activity have been studied.     

The synthesis and structural studies of mixed ligand complex,tris(1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one)mono(1-phenyl-3-methyl-pyrazol-5-one)neodymium(III) monohydrate

A mixed ligand neodymium complex containing 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one (HPMTFP) and 1-phenyl-3-methyl-pyrazol-5-one (PMP), with molecular formula Nd (PMTFP)₃·PMP·H₂O was synthesized. Its crystal and molecular structure has been determined by single crystal X-ray diffraction method. The complex crystallizes in monoclinic system with space group C⁵₂-P2₁/n. There are four formula units in a cell of dimensions a = 12.837(3), b = 23.763(5), c = 16.810(4) Å, β = 109.58(2)°. The structure has been refined by full-matrix least-squares techniques to a final R value of 0.0487 and R_w value of 0.432. The neodymium atom is coordinated to eight oxygen atoms with the average Nd—O bond length 2.439Å. Its thermostability, and mass spectrum have been discussed.     

Anionic lanthanide complexes with 3-methyl-4-formyl-1-phenyl-5-pyrazolone

The coordination compounds Na[LnL₄] · 2H₂O and [NBu₄][LnL₄] (Ln = Nd, Sm, Eu, Tb; HL is 3-methyl-4-formyl-1-phenyl-5-pyrazolone) have been synthesized and studied by IR spectroscopy and thermogravimetry. According to X-ray diffraction data, the coordination polyhedra of lanthanides are shaped as square antiprisms and formed by the oxygen atoms of four deprotonated moieties of the enol form of 4-formyl-5-pyrazolone. In the complex Na[EuL₄] · 2H₂O, sodium cations are bonded to the two nitrogen atoms of pyrazole heterocycles, combining discrete complex anions into two interpenetrating three-dimensional frameworks. Polycrystalline samples of neodymium(III), samarium(III), and terbium(III) complexes manifest intense luminescence in the spectral regions that are typical for them.     

Catecholase biomimetic catalytic activity of copper(II) complexes with 2-methyl-3-amino-(3H)-quinazolin-4-one

The oxidation of catechol by molecular oxygen in the presence of a catalytic amount of copper(II) complex with 2-methyl-3-amino-(3H)quinazoline-4-one (MAQ) and various anions (Cl⁻, Br⁻, ClO ₄ ⁻ , SCN⁻, NO ₃ ⁻ and SO ₄ ^– ) was studied. The catecholase biomimetic catalytic activity of the copper(II) complexes has been determined spectrophotometrically by monitoring the oxidative transformation of catechol to the corresponding light absorbing o-quinone (Q). The rate of the catalytic oxidation reaction was investigated and correlated with the catalyst structure, time, concentration of catalyst and substrate and finally solvent effects. Addition of pyridine or Et₃N showed a dramatic effect on the rate of oxidation reaction. Kinetic investigations demonstrate that the rate of oxidation reaction has a first order dependence with respect to the catalyst and catechol concentration and obeying Michaelis–Menten Kinetics. It was shown that the catalytic activity depends on the coordination environment of the catalyst created by the nature of counter anions bound to copper(II) ion in the complex molecule and follows the order: Cl⁻ > NO ₃ ⁻ > Br⁻ > SO ₄ ^– > SCN⁻ > ClO ₄ ⁻ . To further elucidate the catalytic activity of the complexes, their electrochemical properties were investigated and the catecholase mimetic activity has been correlated with the redox potential of the Cu²⁺/Cu⁺ couple in the complexes.     

Extraction of cobalt(II) and nickel(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HPMBP) and tri-n-octylamine (TOA)

The extraction of Co(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one ((H)PMBP) and tri-n-octylamine (TOA) is investigated in order to explore the influence of diluents and inorganic anions with synergistic acidic extractant + liquid anion exchanger systems. Although it is proved that the same species [HTOA]⁺ [Co(PMBP)₃]^? is extracted from various inorganic media, with toluene as the diluent, the presence of ClO₄^? SO₄^2? or Cl^? anion modifies the distribution of the anions which are associated to (HTOA)⁺ in the organic phase, leading to different synergistic equilibria; with Cl^? or SO₄^2?: $\text{CO(PMBP)}{}_2$ + $\text{(HTOA}{}^{\mathrm{+}}$,PMBP^?) ?$\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? (log K = 6.10) and with ClO₄^? : $\text{Co(PMBP)}{}_2$ + $\text{HPMBP}$ + $\text{(HTOA}{}^{\mathrm{+}}$,ClO₄^? ? $\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? + H⁺ + ClO₄^? (log K = 2.34) The same synergistic equilibrium is observed for the extraction of Ni(II) from ClO₄^? medium, with a comparable value of the constant (log K = 2.45). The synergistic effect is cancelled in n-octanol.     

Solvent extraction of calcium(II) and strontium(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of calcium and strontium from aqueous solution with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (C_n) in MIBK and benzyl alcohol has been studied. In the extraction of Sr with 4-acyl derivatives-MIBK systems, the pH_1/2 values change with increasing the length of acyl chain in the derivatives. The reagent C₃ is more suitable than the other reagents for the separation of Ca and Sr, using MIBK as solvent.