Theoretical study of the spectral behavior of the complex of a recently synthesized aminoxanthone derivative with copper(II) ion in water and methanol

The complexation of a recently synthesized aminoxanthone derivative, 1-({2-[(2-aminoethyl)amino]ethyl}amino)-6-methyl-9H-xanthen-9-one with Cu(II) in methanol and water solutions, was investigated by spectrofluorimetric and spectrophotometric methods. The possible molecular geometries, bindings, and spectroscopic properties for the formed complex were theoretically studied in detail by the Hyperchem program. The stoichiometry of the complex was determined from spectrophotometric molar ratio methods at 20°C. The spectral data were further treated by KINFIT program to calculate the formation constant of the 1:3 complex and its molar absorptivity. Program DATAN was used to calculate the spectral behavior of the complex in each solution for different mole ratios. A simple equation for the determination of complex stability constant was also evaluated from titration data. Under the optimal conditions, the ligand can be used as a fluorometric indicator for measuring Cu²⁺ ions in aqueous solution.     

Investigation of complexes tannic acid and myricetin with Fe(III)

The pH dependence of the complexes was determined by both potentiometric and spectrophotometric studies. Stability constants and stoichiometries of the formed complexes were determined using slope ratio method. Fe(III) was formed complexes with tannic acid of various stoichiometries, which in the 1:1 molar ratio at pH<3, in the 2:1 molar ratio at pH 3-7 and in the 4:1 molar ratio at pH>7. Fe(III) was formed complexes with myricetin in the 1:2 molar ratio at pH 4 and 5 and in the 1:1 molar ratio at pH 6. Stability constant values were found to be 10(5) to 10(17) and 10(5) to 10(9) for Fe(III)-tannic acid complexes and Fe(III)-myricetin complexes. Both tannic acid and myricetin were possessed minimum affinities to Cu(II) and Zn(II). They had less affinity for Al(III) than for Fe(III).     

FEATURES OF A FLEXIBLE BACKBONE IN THE COORDINATION COMPOUNDS OF A DIOXIME LIGAND: THE CHARACTERIZATION OF SUPRAMOLECULAR AND DINUCLEAR METAL COMPLEXES

Abstract

The grinding of a 2: 1 molar ratio mixture of isonitrosoacetylacetone and 1,3-diaminopropan-2-ol led to formation of the tribasic ligand (H₃L), (1) with two oxime groups and a flexible alcoholic backbone. The 1:2 molar ratio reaction of (1) with CuX₂ produced the planar dinuclear complexes LCu₂(X) nH₂O; × = acetate (2), phenylacetate (3), formate (4), monochloroacetate (5), dichloroacetate (6), trichloroacetate (7), benzoate (8), and p-hydroxybenzoate (9); n = 1 for (2) and (8); n = 2 for (3)-(7); and n = 4 for (9). The copper(II) ions are bridged by the carbox-ylate and the alcoholic oxygen. The strong antiferromagnetic interactions in (2)-(9) are impeded in (5)-(7) by the chloroacetate bridge withdrawing electron density from the carboxylate. The latter bridge is replaced by picrate in the 1:1 molar ratio reaction of (2) with picric acid (10). The 1:1 molar ratio reaction of (1) with copper(II) acetate produced the tetranuclear [HLCu]₂[LCu₂(OAc)] 5H₂O (11), whereas the 2:1 molar ratio reaction, similar to the reaction which led to (8), produced HLCu (12). The latter complex reacted (1:1 molar ratio) with either copper(ll) acetate or nickel(II) acetate to produce complexes (2) and the heterodinuclear LNi-Cu(OAc) 2H₂O (13), respectively. Similar reactions with (11) gave the same complexes (2) and (13). The acid adducts of (9) with p-hydroxybenzoic acid (14) and LCu₂(X)-HX (15); × = p-aminobenzoic acid were isolated. The cobalt(II) analogue of the mononuclear (12), HLCo 2H₂O (16) was obtained from the 1:1 molar reaction of (1) with cobalt(II) acetate. The supramolecular structure of (11), (12) and (16) took place via intermolecular hydrogen bonding of the alcoholic proton with the oximato oxygen of the adjacent molecule which mediated electron density and allowed for a magnetic exchange interaction. The suggested structures of the ligand and metal complexes are in accordance with analytical, spectral and magnetic moment data.     

Studies on the Chelation of Cyclodiphosph(V)azane Complexes of Co(II), Ni(II), Cu(II), and Pd(II): Preparation,Characterization, Thermal,Solid State Electrical Conductivity,and Biological Activity Studies

Cyclodiphosph(V)azane of chromene, (1,3-diphenyl-2,4-bis(3-amino-9-methoxy1-tolyl-3H-benzo[f]chromene-2-carbonitrile)-2,2,4,4-tetrachlorocyclodiphosph(V)azane (III), reacts with stoichiometric amounts of transition metal salts such as Co(II), Ni(II), Cu(II), and Pd(II) to afford colored complexes in a moderate to high yield. The structure of the isolated complexes was suggested based on elemental analyses, IR, molar conductance, UV-Vis, ¹H, ¹³C, and ³¹P-NMR, magnetic susceptibility measurements, and dark electrical conductivity of solid state from room temperature up to 450 K. The complexes have been investigated in solution by spectrophotometric molar ratio and conductometric methods. Kinetic and thermodynamic parameters were computed from the thermal decomposition data using the Coats and Redfern method. The prepared complexes showed high to moderate bactericidal activity compared with the ligand.     

Synthesis,Structural, and Antibacterial Studies of Some Mixed Ligand Complexes of Zn(II), Cd(II), and Hg(II) Derived From Citral Thiosemicarbazone and N-Phthaloyl Amino Acids

A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with cis-3,7-dimethyl-2,6-octadienthiosemicarbazone (CDOTSC; LH) and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal dichloride with ligands CDOTSC and N-phthaloyl derivative of DL-glycine (A₁H), L-alanine (A₂H), or L-valine (A₃H) in a 1:1:1 molar ratio in dry refluxing ethanol. All the isolated complexes have the general composition [M(L)(A)]. The plausible structure of these newly synthesized complexes has been proposed on the basis of elemental analyses, molar conductances, molecular weight measurement, and various spectral (IR, ¹H NMR, and ¹³C NMR) studies, and four coordinated geometries have been assigned to these complexes. All the complexes and ligands have been screened for their antibacterial activity.     

Synthesis,spectroscopic (IR,electronic, FAB-mass,and PXRD), magnetic,and antimicrobial studies of new iron(III) complexes containing Schiff bases and substituted benzoxazole ligands

Mixed ligand complexes of iron(III), [Fe(sb)₂(py)Cl]?·?2H₂O (1–9) [where sbH?=?Schiff bases (derived from condensation of 2-aminopyridine (sapH), 2-aminophenol (saphH), o-toluidine (o-smabH), aminobenzene (sabH), p-toluidine (p-smabH), 3-nitroaniline (snabH), and anthranilic acid (saaH) with salicylaldehyde and substituted (mercapto-)benzimidazole (mbzH), {2-(o-hydroxyphenyl)}benzoxazole, (pboxH)], have been synthesized by the interactions of iron(III) chloride with corresponding ligands in 1?:?2 molar ratio in refluxing pyridine. These complexes have been characterized by elemental analyses, melting points, spectral, and magnetic studies. Powder X-ray diffraction studies of some representative complexes are also reported herein. The antibacterial and antifungal activities of the free ligands and their iron(III) complexes were found in vitro. The complexes showed good antibacterial and antifungal effect to some bacteria and fungi. Two standard antibiotics (chloromphenicol and terbinafine) were used for comparison with these complexes.     

In Process Citation

An ultraviolet spectrophotometric study of the complexes formed by anthranil-N,N-diacetic acid, ANDA, with gallium(III) and indium(III) has led to the development of an analytical method for the determination of these elements. The influence of some foreign ions which accompany these elements in nature was checked. The 1:1 ratio of these Me-ANDA complexes was proved by the continuous variation, the slope ratio, and the molar ratio methods. The stability of the complexes was estimated by computing the instability constant K = 7.2 x 10(-7) in the case of Ga-ANDA, and K = 1.1 x 10(-8) for the In-ANDA complex.     

Potentiometric and conductometric studies of malonyl bis(salicyloylhydrazone) and divalent metal complexes

A series of complexes of divalent transition metal ions with malonyl bis(salicyloylhydrazone) (H₄MSH) have been prepared and characterized with the help of conductometric, potentiometric methods. The proton–ligand and metal–ligand stability constants were obtained pH-metrically. The electrical conductivity of solid complexes was measured at 289 K. The low molar conductance values observed for these complexes indicate that, they are non-electrolytes. They are soluble to a limited extent in DMF and DMSO. The elemental analyses of the complexes indicate that the complexes have 1:1 and 2:1 (M:L) stoichiometry with the existence of water, chloride, acetone molecules inside the coordination sphere as evidence from the IR spectral studies. Further, the complexes have been formulated by comparing C, H, N & metal analysis data, and UV–visible spectra of the complexes have been discussed. The protonation constants of the ligand and the stability constants of their metal complexes will be evaluated potentiometrically. The stoichiometric ratios of the complexes formed in solution will be evaluated applying the molar ratio (spectrophotometric) method and confirmed conductometrically.     

Synthesis,characterization, potentiometry,and antimicrobial studies of transition metal complexes of a tridentate ligand

Complexes of Cu(II), Ni(II), Co(II), Mn(II), and Fe(III) with the tridentate Schiff base, 4-hydroxy-3(1-{2-(benzylideneamino)-phenylimino}-ethyl)-6-methyl-2H-pyran-2-one (HL) derived from 3-acetyl-6-methyl-(2H)-pyran-2,4(3H)-dione (dehydroacetic acid or DHA), o-phenylenediamine, and benzaldehyde were characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, ¹H-NMR, UV-Vis spectroscopy, and mass spectra. From analytical data, the stiochiometry of the complexes was found to be 1?:?2 (metal?:?ligand) with octahedral geometry. The molar conductance values suggest nonelectrolytes. X-ray diffraction data suggest monoclinic crystal systems. IR spectral data suggest that the ligand is dibasic tridentate with ONN donors. To investigate the relationship between formation constants of metal complexes and antimicrobial activity, the dissociation constants of Schiff base and stability constants of its binary metal complexes have been determined potentiometrically in THF–water (60?:?40) at 30?±?1°C and at 0.1?mol?L^?1 NaClO₄ ionic strength. The potentiometric titrations suggest 1?:?1 and 1?:?2 complexation. Antibacterial and antifungal activities in vitro were performed against Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Trichoderma with determination of minimum inhibitory concentrations of ligand and metal complexes. The structure–activity correlation based on stability constants of metal complexes is discussed. Activity enhances upon complexation and the order of activity is in accord with the stability order of metal ions.     

Synthesis and characterization of mixed ligand complexes of cobalt(II) with some nitrogen and sulfur donors

Mixed ligand complexes of Co(II) with nitrogen and sulfur donors, Co(OPD)(S–S) · 2H₂O and Co(OPD)(S–S)L₂ [OPD = o-phenylenediamine; S–S = 1,1-dicyanoethylene-2,2-dithiolate (i-MNT^2?) or 1-cyano-1-carboethoxyethylene-2,2-dithiolate (CED^2?); L = pyridine (py), α-picoline (α-pic), β-picoline (β-pic), or γ-picoline (γ-pic)], have been isolated and characterized by analytical data, molar conductance, magnetic susceptibility, electronic, and infrared spectral studies. The molar conductance data reveal non-electrolytes in DMF. Magnetic moment values suggest low-spin and high-spin complexes. The electronic spectral studies suggest distorted octahedral stereochemistry around Co(II) in these complexes. Infrared spectral studies suggest bidentate chelating behavior of i-MNT^2?, CED^2?, or OPD while other ligands are unidentate in their complexes.     

Synthesis,Spectroscopic Characterization,and Antifungal Activity of Some Mixed Ligand Complexes of Zn(II), Cd(II), and Hg(II)

A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with citronellal thiosemicarbazone [3,7-dimethyl-6-octene-1-a1 thiosemicarbazone (LH)] and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal(II) chloride with ligands citronellal thiosemicarbazone (DOTSC) and N-phthaloyl glycine [1,3-dihydro-1,3-dioxo-2H-isoindole-2-acetic acid (A₁H)] or N-phthaloyl alanine [1,3-dihydro-1,3-dioxo-α(methyl)-2H-isoindole-2-acetic acid (A₂H)] in 1:1:1 molar ratio in dry refluxing ethanol. All the complexes have been characterized by elemental analyses, molar conductance measurement, molecular weight measurement, IR, and multinuclear NMR (¹H and ¹³C{¹H}) spectral studies. IR, ¹H, and ¹³C{¹H} NMR spectral studies suggest the involvement of azomethine-N, thiol-S atoms of the thiosemicarbazone moiety and both carboxylate-O of N-phthaloyl amino acid moiety in coordination with central metal(II) ion, and four coordinated geometries have been assigned to these complexes. The free ligands and metal complexes have been screened for their antifungal activity against two fungal strains, Fusarium moniliformae and Macrophomina phaseolina, using the the radial growth method. The results of antifungal activity show that metal complexes show enhanced higher activity than the free ligands.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their addition complexes with N,P donor ligands: synthesis,spectral and antimicrobial investigations

Iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates of the type (C₁₅H₁₂N₂OX)₃Fe [where X =–H,–Cl,–CH₃,–OCH₃] have been synthesized by reaction of anhydrous FeCl₃ with the sodium salts of pyrazoline in 1 : 3 molar ratio. Their addition complexes with N and P donor ligands [2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine] were prepared in 1:1 molar ratio. These newly synthesized derivatives have been characterized using elemental analysis (C, H, N and Fe), molecular weight measurement, magnetic moment data, FAB mass, ³¹P NMR and Mössbauer spectral data. The complexes have been examined for crystalline/amorphous nature through XRD; all complexes are amorphous. Octahedral geometry around iron(III) confirms the presence of three bidentate pyrazoline ligands in iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In addition complexes pyrazoline is monodentate. The bidentate and monodentate behavior of pyrazoline ligands was confirmed by IR spectral data. All the complexes were tested for their in-vitro antimicrobial activity. The metal complexes and their adducts exhibit better antibacterial and antifungal activity than the pyrazolines.     

Zinc(II) 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their adducts with N and P donor ligands: synthesis,spectral, biological,and anti-inflammatory investigations

Synthesis, spectral, biological, and anti-inflammatory investigations of a series of complexes of zinc(II) with 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolines of the type (C₁₅H₁₂N₂OX)₂Zn (where X =–H,–Cl,–CH₃,–OCH₃) are presented. The complexes were synthesized by reaction of anhydrous zinc(II) chloride with sodium salts of pyrazoline in 1 : 2 molar ratio. Adducts with N and P donor ligands (2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine) were prepared in 1 : 1 molar ratio. The complexes were characterized by elemental analyses, molecular weight, conductivity, IR, electronic, ¹H, ¹³C, ³¹P NMR, and FAB mass spectral studies. All complexes are amorphous. Tetrahedral geometry around zinc confirms the presence of two bidentate pyrazoline ligands in zinc(II) 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In adducts pyrazoline is monodentate. Bidentate and monodentate pyrazoline were confirmed by IR, ¹H, ¹³C, and ³¹P NMR spectral data. All metal complexes were tested for their antibacterial and antifungal activities. Anti-inflammatory activity was also carried out by the carrageenan-induced rat paw edema test. Brine shrimp bioassay was also carried out to study in-vitro cytotoxic properties.     

Synthesis,spectroscopic, antibacterial and antifungal studies of nickel(II)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their addition complexes with N and P donor ligands

A number of complexes of nickel(II) with 5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolines of the type (C₁₅H₁₂N₂O ··· X)₂Ni [where X = H, Cl, CH₃ and OCH₃] were synthesized by the reaction of anhydrous nickel(II) chloride with sodium salts of pyrazoline in 1 : 2 molar ratio. Their addition complexes with 2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine were prepared in 1 : 1 molar ratio. These complexes were characterized by elemental analyses, molecular weight, magnetic, conductivity, IR, electronic, ¹H, ¹³C, ³¹P NMR and FAB mass spectral data. All complexes are amorphous. Square planar geometry around nickel confirms the presence of two bidentate pyrazoline ligands in nickel(II)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In the addition complexes pyrazoline is monodentate. Bidentate and monodentate pyrazoline was confirmed by IR, ¹H, ¹³C and ³¹P NMR spectral data. All the metal complexes exhibit very good antibacterial and antifungal activity. Coordination of metal ion has pronounced effect on the microbial activities of the ligand. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties; all complexes and adducts display potent cytotoxic activity against Artemia salina.     

A Novel Synthesis of 2-Amino-2-deoxy-D-gluconic Acid and Its Complexation with Cu（Ⅱ） in Alkaline Medium

A novel synthesis of the functional carbohydrate 2-amino-2-deoxy-D-gluconic acid was introduced and itscomplex formation with Cu(Ⅱ)was investigated to obtain the stability constant for its further applications to thefood and pharmaceutical industries.The equilibrium was investigated by spectrophotometric measurements andprocessed by dual-series linear regression method.Results:the yield of 2-amino-2-deoxy-D-gluconic acid is 70%.The complexation molar ratio is 1:2,the molar apsorptivity of the complex is 39.906 L·mol~(-1)·cm~(-1) at 630 nm,and the stability constant β_n is 6.24×10~5.     

Spectrophotometric investigation of Ti(IV) complexes of N-phenylacetylphenylhydroxylamine

N-Phenylacetylphenylhydroxylamine complexes of titanium(IV), yellow in color and extractable into chloroform, with metal:ligand ratios 1:2, 1:3, and 1:4, exist in the acidity ranges of 1–3, 4–7, and 7.5–9.0 N HCl, respectively. The compositions of the complexes were found out by Job's and molar ratio methods. The stepwise and overall formation constants were evaluated following extensions of Yatsimirskii's, Leden's and Harvey and Manning's methods. A computer was used for evaluation of the formation constants of the 1:3 system following the first method. A spectrophotometric method based on solvent extraction technique, for determination of trace amounts of titanium in the presence of diverse ions, has also been described.     

Spectrophotometric determination of vanadium(V) as a mixed thiocyanate-4-pyridone complex

The spectrophotometric determination of vanadium(V) as a mixed thiocyanate-3-hydroxy-2-methyl-1-phenyl-4-pyridone (HX) complex and as a mixed thiocyanate-3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone (HY) complex is described. The extracted complexes in chloroform have a maximum absorbance at 450 and 650 nm. The optimal conditions for the extraction and spectrophotometric determination of vanadium(V) are determined. The solutions of the V-SCN-HX and V-SCN-HY complexes in chloroform obey Beer's law in the range 1–10 ppm of vanadium, and are stable for at least 24 hr. The molar absorptivity of the method is 6.8 × 10³ liters mol^?1 cm^?1. The molar ratio V:SCN:HX (HY) of the extracted complex is 1:1:2.     

Spectrophotometric Investigation of Ti(IV) Complex of N-Pyridyl-N′ β-naphthylthiourea

The intense yellow colored complexes of Ti(IV) and N-pyridy1-N′-β-naphthylthiourea are extractable into isoamyl alcohol. The spectrophotometric studies following Job's and molar ratio methods have shown that 1:2 and 1:3 (meta1:ligand) complexes predominate in the acidity ranges of 2.5–6 and 7–9.5 N HCl, respectively. The values of the stability constants, sepwise and overall, have been calculated following extended Leden's, Yatsimirskii's, and Harvey-Manning's methods. The analytical suitability of the reagent for microdetermination of titanium has also been investigated.     

Synthesis,characterization, and antimicrobial activity of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with ferrocenyl Schiff bases containing a phenol moiety

Three ferrocenyl Schiff bases containing a phenol moiety have been formed by 1:1 molar condensation of acetylferrocene with 2‐aminophenol, 2‐amino‐5‐picoline or 2‐amino‐5‐chlorophenol. These ligands form 2:1 complexs with cobalt(II), copper(II), nickel(II), and zinc(II) ions. From the different spectral data, it was found that coordination of the ligands with the metal ions takes place via the azomethine nitrogen atoms and the deprotonated oxygen of the phenol groups. These ligands and their complexes have been characterized by IR, ¹H NMR, ¹³C NMR, UV–Vis spectra, and elemental analysis. The spectral data of the ligands and their complexes are discussed in connection with the structural changes due to complexation. The complexes prepared showed good antimicrobial activity against Escherichia coli, Bacillus subtilus, and Candida albicans. Copyright © 2004 John Wiley & Sons, Ltd.     

Polymer complexes. LV. Spectroscopic,thermal studies,and coordination of metal ions N-[3-(5-amino-1,2,4-triazolo)] acrylamide polymer complexes

Novel polymeric complexes with a potentially bidentate ligand formed by amidation of 3,5-diamino-1,2,4-triazole with acryloyl chloride were synthesized and characterized on the basis of elemental analyses, IR, ¹H-NMR, UV-Vis, magnetic susceptibility measurements, molar conductance, and thermal analyses. The molar conductance data reveal that all the polymer complexes are non-electrolytes. Spectral studies reveal that the free ligand coordinates bidentate to the metal ion through the oxygen of the carbonyl and azomethine of the heterocyclic ring. Elemental analyses of the polychelates indicate the metal to ligand ratio of 1?:?1/1?:?2. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry has been proposed for each polymeric complex. The electron spin resonance spectral data of the Cu(II) complex showed that the metal–ligand bonds have considerable covalent character. The thermal behavior of these chelates shows that the polymer complexes lose coordinated water in the first step immediately followed by decomposition of the anions and ligand molecules in a subsequent step.