Superior adsorption and removal of industrial dye from aqueous solution via magnetic silver metal-organic framework nanocomposite

The indirect emission had a negative influence on the ecosystem of enormous amounts of harmful dyes into water. Fe3O4@Ag-MOF was successfully fabricated to capture Gentine violet (GV)) as a model example of cationic dye from their aqueous solutions was evaluated in this search as a method to eliminate dyes from water contaminants. FTIR, XPS, BET, TGA, SEM, TEM, and XRD have all been used to study this adsorbent in order to determine its structural and chemical characteristics as well as to interpret its binding mechanisms. According to the results of the characterization, the synthesized composite had a size about 45 nm, a surface area of 856.06 m2/g, and considerable magnetic characteristics (66.2 emug-1). Consequently, we created mesoporous surfaces that had a strong ability to interface and absorb GV dye. It is possible to use the pseudo-second order rate equation to characterize the kinetic profile., while the Langmuir equation fits isotherm models. At pH 9, maximum sorption capacities can reach 1.68 mmol.g-1. Additionally, the investigations of temperature profiles indicated the endothermic process and Thermodynamic parameters were discovered as, ΔG°, ΔH° and ΔS° The synthesized adsorbent had an interestingly high reusability of > 92 percent up to the sixth cycle. These findings revealed that a mixture of electrostatic interactions, π-π stacking, hydrogen bonds, and pore filling were involved in the GV adsorption mechanism. Fe3O4@Ag-MOF was successful in demonstrating its effectiveness as a point-of-use colour collection candidate from actual dyeing effluents.

Effective levofloxacin adsorption and removal from aqueous solution onto tea waste biochar; synthesis, characterization, adsorption studies, and optimization by Box-Behnken design and its antibacterial activity

ABSTRACTResearch efforts are focusing on investigating cost-effective and ecologically friendly ways to create nanoparticles as a result of promising developments in green technology (NPs). This experiment focused on the effectiveness of using biochar (TWB) made from coffee waste to extract levofloxacin (LEV) from water. The conclusive results of the trials showed that TWB is an effective adsorbent for removing LEV from liquid solutions. The TWB produced through biological processes underwent comprehensive analysis using techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area measurement (BET), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The bioengineered TWB's exceptional crystalline properties, which closely resemble the monoclinic structure of bulk TWB, were confirmed by the XRD analysis. Based on the scanning electron microscopy (SEM) data, the synthesis of TWB Nanoparticles resulted in the formation of spherical particles with an approximate diameter of 40 nm, accompanied by a substantial surface area of 285.55 m²/g. The Pseudo-Second-Order model, which best captured Levofloxacin's adsorption characteristics, was evaluated on the TWB, and the results showed that external mass transfer was the main determinant of response rate. It was also found that the adsorption process was endothermic and spontaneous. The system was optimized using the Box-Behnken design (BBD) methodology. The achieved removal capacity of 1119.19 mg/g utilizing the tested adsorbent was determined to be reasonable when compared to the performance of other previously used adsorbents when evaluating the effectiveness of eliminating LEV. The process of LEV adsorption onto TWB involves a number of different mechanisms, such as ion exchange, π-π interactions, electrostatic pore filling, and hydrogen bonding. Following extensive testing in connection with a real-world sample, the adsorbent demonstrated remarkable efficacy, and it maintained good performance even after undergoing three further regeneration cycles. By adjusting the annealing temperature, we controlled the synthesis of TWB nanoparticles across a range of sizes in order to maximize their antibacterial capabilities. This research utilized a pair of Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and a pair of Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) to evaluate the antibacterial efficacy of TWB.

Adsorption of Azorubine E122 dye via Na-mordenite with tryptophan composite: Batch adsorption, Box-Behnken design optimization and antibacterial activity

In the current investigation, we have reported on the preparation of Na-Mordenite (MOR) modified by tryptophan (MOR-NH₂) nanocomposite was synthesized and characterized using FT-IR, XRD, SEM, XPS, and BET that represented that the MOR-NH₂ has high surface area 288 m²/g and pore volume 0.38 cm³/g. This composite represented high efficiency in removal of food dye Azorubine (E122) was 1043 mg/g. Study all the factors that affected on the adsorption such as pH, dose, salinity, E122 dye concentration as well as study the adsorption isotherm models that represented that was fitted to Langmuir. Moreover, study the effect of time according to it the adsorption process was fitted to Pseudo-second-order, and the effect of temperature that approved that the reaction was endothermic, spontaneous, and chemisorption process. pHzpc was determined to be 6.2 that mean that favorable to adsorb the anionic dyes such as E122 dye to <6.2. The adsorption process was optimized using Box-Behnken Design (BBD). The MOR-NH₂ adsorbent demonstrated a simple and effective model for water purification and the management of industrial wastewater specially the regeneration efficiency of the adsorbent that led to use this adsorbent for five cycles. The MOR-NH₂ nanocomposite was tested and proven to effectively inhibit the growth of Escherichia coli ATCC® 25922™ and Staphylococcus aureus ATCC® 25923™ at low concentrations. The impressive antibacterial capabilities and dye removal of the ZMOR-NH₂ nanocomposite make it an excellent choice for antibacterial solutions! To the best of our knowledge, this work is the first to report the usage of MOR-NH₂ adsorbents for the removal of E122 dye in wastewater samples. The effects of adsorption process the effects of adsorption process. The mechanism of interaction between MOR-NH₂ and E122 dye was determining as it could be through Hydrogen bonding, pore filling, or through π- π interaction. This research offers a promising solution for purifying water sources that are contaminated with a variety of chemicals, microorganisms, and other contaminants. With the potential for future breakthroughs in purification methods, this study is envisioned to lead the way for new nanocomposite materials which could be used to remove an array of pollutants -from hazardous chemicals to viruses and bacteria.

Fabricating of Fe3O4@Ag-MOF nanocomposite and evaluating its adsorption activity for removal of doxorubicin

The purpose of this research was to investigate the doxorubicin (DOX) adsorption behavior on Fe3O4@Ag-Metal Organic Framework (Fe₃O₄@Ag-MOF). This adsorbent was effectively prepared using a simple synthetic process. Many instruments, including FTIR, XRD, SEM, TEM, and XPS, were used to characterized the new Fe₃O₄@Ag-MOF. Additionally, the presented Fe₃O₄@Ag-surface MOF's area was shown to be 586.06 m2/g with a size of around 43 nm. The composite that was made has magnetic properties that were quite strong (63.3 emu/g). The produced Fe₃O₄@Ag-MOF was discovered to have a fantastic ability to adsorb the anti-cancer drug DOX, with a 1.72 mmol/g (934.85 mg/g) adsorption capacity. On the basis of changes in temperature, pH, and DOX concentration, the DOX adsorption behavior mechanism was investigated. The adsorption capacity of Fe₃O₄@Ag-MOF for DOX was greater at pH 7.0, according to experimental data. The adsorption equilibrium also demonstrated that the Langmuir adsorption was regulated the best fit to the extracted data compared with the other models. Additionally, the activation energy of adsorption for DOX onto Fe₃O₄@Ag-MOF was determined, indicating the chemisorption process. The adsorption kinetics was shown in the well-known kinetic model of the pseudo-second-order. The adsorption thermodynamic measurements were documented according to according to the enthalpy (ΔH°), entropy(ΔS°), and Gibbs free energy (ΔG°) parameters demonstrated that the reaction was endothermic and spontaneous thermodynamic. The adsorption of DOX onto Fe₃O₄@Ag-MOF from real water samples (tap water, effluent wastewater, and influence wastewater) were investigated. It's interesting that the synthetic adsorbent had great recyclability 72.6 percent in the fifth cycle indicating that it was highly recyclable. After adsorption, the typical Fe₃O₄@Ag-MOF XRD peak intensities and locations were mostly unchanged throughout adsorption indicates the crystalline phase remained steady. The results indicated that Fe₃O₄@Ag-MOF were a good candidate for adsorbing the DOX and treating wastewater.

Novel imidazolium-thiohydantoin hybrids and their Mn(iii) complexes for antimicrobial and anti-liver cancer applications

We present the effective synthesis and structural characterization of three novel imidazolium-thiohydantoin ligands (IMTHs, 5a–c) and their Mn(iii) complexes (Mn(iii)IMTHs, 6a–c) in this study. The findings of elemental analyses, spectral analyses and magnetic measurements will be used to infer the stoichiometry, coordination styles, and geometrical aspects of Mn(iii)IMTHs. The new compounds were evaluated for their chemotherapeutic potential against ESKAPE pathogens and liver cancer (HepG2). According to the MIC and MBC values, the bactericidal and bacteriostatic activities of IMTHs have been significantly improved following coordination with the Mn(iii) ion. The MTT assay results showed that all Mn(iii)IMTHs had the potential to reduce the viability of liver carcinoma (HepG2) cells in a dose-dependent manner, with the BF₄-supported complex (6b) outperforming its counterparts (6a and 6c) as well as a clinical anticancer drug (VBL). Additionally, Mn-IMTH₂ (6b) showed the highest level of selectivity (SI = 32.05) for targeting malignant cells (HepG2) over healthy cells (HL7702).

We present the effective synthesis and structural characterization of three novel imidazolium-thiohydantoin ligands (IMTHs, 5a–c) and their Mn(iii) complexes (Mn(iii)IMTHs, 6a–c) in this study.

Fluorescence enhancement of rhodamine B as a tool for the determination of trace and ultra-trace concentrations of bismuth using dispersive liquid–liquid microextraction

The present work describes a simple, sensitive, selective, and eco-friendly spectrofluorimetric method for bismuth determination in wastewaters and dyed scalp hair.

Adsorption of toxic acidic dye from aqueous solution onto diethylenetriamine functionalized magnetic glycidyl methacrylate-N,N′-methylenebisacrylamide

Magnetic sorbent microgranules with magnetite (Fe₃O₄) core and glycidyl methacrylate/N,N′​-methylenebisacrylamide shell were prepared. The sorbent was tested for Acid Yellow 99 dye removal from aqueous solution.

Sorptive removal of Remazol Brilliant Blue R from aqueous solution by diethylenetriamine functionalized magnetic macro-reticular hybrid material

Chitosan, glycidyl methacrylate (synthetic polymer) and magnetite are combined to produce novel magnetic macro-reticular hybrid synthetic–natural materials which are shown to be effective sorbents for RBBR ions.

Comparison of commercial analytical techniques for measuring chlorine dioxide in urban desalinated drinking water

Most drinking water industries are closely examining options to maintain a certain level of disinfectant residual through the entire distribution system. Chlorine dioxide is one of the promising disinfectants that is usually used as a secondary disinfectant, whereas the selection of the proper monitoring analytical technique to ensure disinfection and regulatory compliance has been debated within the industry. This research endeavored to objectively compare the performance of commercially available analytical techniques used for chlorine dioxide measurements (namely, chronoamperometry, DPD (N,N-diethyl-p-phenylenediamine), Lissamine Green B (LGB WET) and amperometric titration), to determine the superior technique. The commonly available commercial analytical techniques were evaluated over a wide range of chlorine dioxide concentrations. In reference to pre-defined criteria, the superior analytical technique was determined. To discern the effectiveness of such superior technique, various factors, such as sample temperature, high ionic strength, and other interferences that might influence the performance were examined. Among the four techniques, chronoamperometry technique indicates a significant level of accuracy and precision. Furthermore, the various influencing factors studied did not diminish the technique's performance where it was fairly adequate in all matrices. This study is a step towards proper disinfection monitoring and it confidently assists engineers with chlorine dioxide disinfection system planning and management.

Correlation between ionic radii of metal azodye complexes and electrical conductivity

5-(2,3-Dimethyl-1-phenylpyrazol-5-one azo)-2-thioxo-4-thiazolidinone (HL) and its metal complexes with copper(II) (1), cobalt(II) (2) and nickel(II) (3) are synthesized and characterized by physico-chemical techniques. The thermal properties of the ligand (HL) and its metal complexes (1-3) are discussed. The thermal activation energies of decomposition (Ea) of HL and its metal complexes with Cu(II), Co(II) and Ni(II) are found to be 48.76, 36.83, 30.59 and 40.45 kJ/mol, respectively. The frequency and temperature dependence of ac conductivity, dielectric constants for HL and its complexes (1-3) are investigated in the temperature range 300-356 K and frequency range 0.1-100 kHz. Both of the ac conductivity and the values of the thermal activation energy for conduction, as well as the dielectric properties of the complexes of HL are found to depend on the nature of the metallic ions. The values of the thermal activation energies of electrical conductivity decrease with increasing the value of test frequency. The small polarons tunneling (SPT) is the dominant conduction mechanism for the ligand (HL), while for complex (2) the overlapping large tunneling model (OLPT) is the dominant conduction mechanism. The correlated barrier hopping (CBH) is the dominant conduction mechanism for both of the complexes (1) and (3).

Ternary metal complexes of guaifenesin drug: Synthesis, spectroscopic characterization and in vitro anticancer activity of the metal complexes

The coordination behavior of a series of transition metal ions named Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a mono negative tridentate guaifenesin ligand (GFS) (OOO donation sites) and 1,10-phenanthroline (Phen) is reported. The metal complexes are characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, UV-vis spectral studies, mass spectroscopy, ESR, XRD and thermal analysis (TG and DTG). The ternary metal complexes were found to have the formulae of [M(GFS)(Phen)Cl]Cl·nH2O (M=Cr(III) (n=1) and Fe(III) (n=0)), [M(GFS)(Phen)Cl]·nH2O (M=Mn(II) (n=0), Zn(II) (n=0) and Cu(II) (n=3)) and [M(GFS)(Phen)(H2O)]Cl·nH2O (M=Co(II) (n=0), Ni(II) (n=0) and Cd(II) (n=4)). All the chelates are found to have octahedral geometrical structures. The ligand and its ternary chelates are subjected to thermal analyses (TG and DTG). The GFS ligand, in comparison to its ternary metal complexes also was screened for their antibacterial activity on gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), gram negative bacteria (Escherichia coli and Neisseria gonorrhoeae) and for in vitro antifungal activity against (Candida albicans). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent GFS ligand. The complexes were also screened for its in vitro anticancer activity against the Breast cell line (MFC7) and the results obtained show that they exhibit a considerable anticancer activity.

Thermal, dielectric characteristics and conduction mechanism of azodyes derived from quinoline and their copper complexes

A novel series of (5-(4'-derivatives phenyl azo)-8-hydroxy-7-quinolinecarboxaldehyde) (AQLn) (n=1, p-OCH3; n=2, R=H; and n=3; p-NO2) and their complexes [Cu(AQLn)2]·5H2O are synthesized and investigated. The optimized bond lengths, bond angles and the calculated quantum chemical parameters for AQLn are investigated. HOMO-LUMO energy gap, absolute electronegativities, chemical potentials, and absolute hardness are also calculated. The thermal properties, dielectric properties, alternating current conductivity (σac) and conduction mechanism are investigated in the frequency range 0.1-100kHz and temperature range 293-568K for AQL1-3 and 318-693K for [Cu(AQL1-3)2]·5H2O complexes. The thermal properties are of ligands (AQLn) and their Cu(II) complexes investigated by thermogravimetric analysis (TGA). The temperature and frequency dependence of the real and the imaginary part of the dielectric constant are studied. The values of the thermal activation energy of conduction mechanism for AQLn and their complexes [Cu(AQLn)2]·5H2O under investigation are calculated at different test frequencies. The values of thermal activation energies ΔE1 and ΔE2 for AQLn and [Cu(AQLn)2]·5H2O decrease with increasing the values of frequency. The ac conductivity is found to be depending on the chemical structure of the compounds. Different conduction mechanisms have been proposed to explain the obtained experimental data. The small polaron tunneling (SPT) is the dominant conduction mechanism for AQL1 and its complex [Cu(AQL1)2]·5H2O. The quantum mechanical tunneling (QMT) is the dominant conduction mechanism for AQL2 and its complex [Cu(AQL2)2]·5H2O. The correlated barrier hopping (CBH) is the dominant conduction mechanism for AQL3 and its complex [Cu(AQL3)2]·5H2O, and the values of the maximum barrier height (Wm) are calculated.

Polymer complexes. LX. Supramolecular coordination and structures of N(4-(acrylamido)-2-hydroxybenzoic acid) polymer complexes

A number of novel polymer complexes of various anions of copper(II), cobalt(II), nickel(II) and uranyl(II) with N(4-(acrylamido)-2-hydroxy benzoic acid) (ABH) have been synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurements, electronic spin resonance, vibrational spectra and thermal analysis. The molecular structures of the ligand are optimized theoretically and the quantum chemical parameters are calculated. Tentative structures for the polymeric metal complexes due to their potential application are also suggested. The IR data exhibit the coordination of ONO2/OAc/SO4 with the metal ions in the polymeric metal complex. Vibrational spectra indicate coordination of carboxylate oxygen and phenolic OH of the ligand giving a MO4 square planar chromophore. Ligand field ESR spectra support square planar geometry around Cu(II). The thermal decomposition of the polymer complexes were discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coast-Redfern and Horowitz-Metzger methods.

Optical and thermal properties of azo derivatives of salicylic acid thin films

N-acryloyl-4-aminosalicylic acid (4-AMSA), monomer (HL) and 5-(4'-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are synthesized and characterized with various physico-chemical techniques. Thin films of 5-(4'-alkyl phenylazo)-N-acryloyl-4-aminosalicylic acid (HLn) are prepared by spin coating technique. The X-ray diffraction (XRD) patterns of 4-aminosalicylic acid (4-ASA) and its derivatives are investigated in powder and thin film forms. Thermal properties of the compounds are investigated by thermogravemetric analysis (TGA). The optical energy gap and the type of optical transition are investigated in the wavelength range (200-2500 nm) for 4-ASA, HL and HLn. The values of fundamental energy gap (Eg) are in the range 3.60-3.69 eV for all compounds and the type of optical transition is found to be indirect allowed. The onset energy gap Eg(∗) appeared only for azodye compounds is found to be in the range 0.95-1.55 eV depending on the substituent function groups. The refractive index, n, shows a normal dispersion in the wavelength range 650-2500 nm, while shows anomalous dispersion in the wavelength rang 200-650 nm. The dispersion parameters ε∞, εL, Ed, Eo and N/m(∗) are calculated. The photoluminescence phenomena (PL) appear for thin films of 4-ASA and its derivatives show three main emission transitions.

Correlation between ionic radii of metals and thermal decomposition of supramolecular structure of azodye complexes

An interesting azodye heterocyclic ligand of copper(II), cobalt(II), nickel(II) and uranyl(II) complexes have been synthesized by the reaction of metal salts with 5-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-2-thioxo-4-thiazolidinone (HL) yields 1:1 and 1:2 (M:L) complexes depending on the reaction conditions. The elemental analysis, magnetic moments, spectral (UV-Vis, IR, (1)H and (13)C NMR and ESR) and thermal studies were used to characterize the isolated complexes. The molecular structures of the ligand tautomers are optimized theoretically and the quantum chemical parameters are calculated. The IR spectra showed that the ligand (HL) act as monobasic tridentate/neutral bidentate through the (-N=N), enolic (C-O)(-) and/or oxygen keto moiety groups forming a five/six-membered structures. According to intramolecular hydrogen bond leads to increasing of the complexes stability. The molar conductivities show that all the complexes are non-electrolytes. The ESR spectra indicate that the free electron is in dxy orbital. The calculated bonding parameter indicates that in-plane σ-bonding is more covalent than in-plane π-bonding. The coordination geometry is five/six-coordinated trigonal bipyramidal for complex (1) and octahedral for complexes (2-6). The value of covalency factor β1(2) and orbital reduction factor K accounts for the covalent nature of the complexes. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. The synthesized ligand (HL) and its Cu(II) complexes (1, 2 and 4) are screened for their biological activity against bacterial and fungal species. The ligand (HL) showed antimicrobial activities against Escherichia coli. The ligand (HL) and its Cu(II) complexes (2 and 4) have very high antifungal activity against Penicillium italicum. The inhibitive action of ligand (HL), against the corrosion of C-steel in 2M HCl solution has been investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).

Synthesis, spectral and catalytic dehydrogenation studies of ruthenium complexes containing NO bidentate ligands

The synthesis and characterization of ruthenium mononuclear complexes containing NO bidentate ligands are reported. The complexes cis-[Ru(II)(bpy)2L](PF6)n (1a-c), [Ru(III)Cl(L)2(H2O)] (2a-b) and [Ru(III)Cl2(L)2]Cl (2c) were prepared by the reaction of cis-[Ru(II)Cl2(bpy)2]·2H2O (bpy=2,2'-bipyridine) and/or RuCl3·nH2O with the Ligands: 2-aminophenol (2-aph), 8-hydroxyquinoline (8-hq) and 4-aminoantipyrine (4-apy). These complexes were characterized by elemental analysis, spectroscopic (IR, UV-Vis, (1)H NMR, ESR) and magnetic susceptibility measurements. The ligand field parameters, Δo (splitting parameter), B (Racah parameter of interelectronic repulsion), and β (nephelauxetic ratio) were calculated. The redox properties were also investigated electrochemically by cyclic voltammetry. The complexes cis-[Ru(II)(bpy)2(8-hq)](PF6)2 (1b) and [Ru(III)Cl(8-hq)2(H2O)] (2b) have been investigated in conjunction with N-methylmorpholine-N-oxide (NMO) as co-oxidant for the catalytic dehydrogenation of benzyl amine, p-methyl benzylamine and p-nitrobenzylamine to their respective nitriles.

Supramolecular spectroscopic and thermal studies of azodye complexes

A series of heterocyclic ligand of copper(II) complexes have been synthesized by the reaction of copper(II) acetate with 5-(4'-derivatives phenylazo)-2-thioxothiazolidin-4-one (HLn) yields 1:1 and 1:2 (M:L) complexes depending on the reaction conditions. The elemental analysis, spectral (IR and ESR), conductance, magnetic measurements, and thermogravimetric analysis (TGA) are used to characterize the isolated complexes. It is found that the change of substituent affects the thermal properties of azodye rhodanine derivatives and their Cu(II) complexes. The molecular and electronic structures of the investigated compounds (HLn) were also studied using quantum chemical calculations. According to intramolecular hydrogen bond leads to increasing of the complexes stability. The data revealed that the coordination geometry around Cu(II) in all complexes (1-4) exhibit a trans square planar by NO monobasic bidentate and the two monobasic bidentate in octahedral complexes (5-7). Electronic, magnetic data and ESR spectra proposed the square planar structure for all complexes (1-4) under investigation. The value of covalency factor [Formula: see text] and orbital reduction factor K accounts for the covalent nature of the complexes. The activation thermodynamic parameters, such as activation energy (Ea), enthalpy (ΔH(*)), entropy (ΔS(*)), and Gibbs free energy change of the decomposition (ΔG(*)) are calculated using Coats-Redfern and Horowitz-Metzger methods.

Chromium(III) Complexes with Some Optically Active α-Hydroxy Acids

Complexes obtained from CrCl3Py3 with some optically active α-hydroxy acids have been characterized by elemental analysis, magnetic susceptibility, vibrational (IR), electronic and circular dichroism (CD) spectra. The magnetic susceptibility data are close to the spin-only value for a d3 chromium(III) ion in octahedral or distorted octahedral symmetry. Three (Cr—Cl) vibrational modes in the region 410-290 cm-1 are observed for some of the complexes indicating C2ν, local symmetry of ligand atoms around the chromium(III). In the electronic spectra two peaks are observed in the range 16949-18018 and 22986-24570 cm-1. They are assigned to d—d transitions in pseudo octahedral symmetry. The structure of the complexes is likely to be facial since strong and well defined Cotton effects are observed. The parameters (Dq, B, β35) for the complexes provide reassurance that pyridine nitrogen is preserved.

Supramolecular spectral studies on metal-ligand bonding of novel quinoline azodyes

A series of novel bidentate azodye quinoline ligands were synthesized with various p-aromatic amines like p-(OCH3, CH3, H, Cl and NO2). All ligands and their complexes have been characterized on the basis of elemental analysis, IR, (1)H and (13)C NMR data and spectroscopic studies. IR and (1)H NMR studies reveal that the ligands (HLn) exists in the tautomeric azo/hydrazo form in both states with intramolecular hydrogen bonding. The ligands obtained contain NN and phenolic functional groups in different positions with respect to the quinoline group. IR spectra show that the azo compounds (HLn) act as monobasic bidentate ligand by coordinating via the azodye (NN) and oxygen atom of the phenolic group. The ESR (g|| and g ) and bonding α(2) parameters of the copper ion were greatly affected by substituting several groups position of ring of quinoline and p-aromatic ring. The ESR spectra of copper complexes in powder form show a broad signal with values in order g|| >g > ge > 2.0023. The value of covalency factor β and orbital reduction factor K accounts for the covalent nature of the complexes. All complexes possessed an octahedral and square planar geometry. The thermal properties of the complexes were investigated using TGA and DSC. It is found that the change of substituent affects the thermal properties of complexes.

Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (L(n)) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and (1)H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(L(n))(2)]Cl(2)⋅2H(2)O. Schiff bases (L(n)) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.

Supramolecular and structural modification on conformational by mixed ligand

A novel series of platinum(II) and palladium(II) complexes have been synthesized by template condensation of 4-methoxybenzaldehyde, benzaldehyde, 4-chlorobenzaldehyde and 4-nitrobenzaldehyde, with appropriate 4-aminoantipyrine (4-AAP) in the presence of K(2)PtCl(4)/PdCl(2) to form complexes of the type [M(L(n))Cl(2)](where M=Pt(II) or Pd(II)). The corresponding Schiff base complexes mixed ligand were prepared by condensation of [M(L(n))Cl(2)] with ethanolamine (LH). The complexes have been characterized with the help of elemental analysis, IR, (1)H and (13)C NMR, electronic spectra, conductance measurements, magnetic susceptibilities and thermal analysis. On the basis of these studies, it is clear that ligands coordinated to metal atom in a mononuclear (NO) in (1-6), Schiff base complexes (NN(*)) in (7-9) and monobasic tridentate Schiff base complexes (NN(*)O) in (10-12). Thus, suitable square planar geometry for tetradentated state has been suggested for the metal complexes. Various ligand and nephelouxetic parameter have been calculated for the complexes. The thermal decomposition for complexes was studied.

Polymer complexes. LVI. Supramolecular architectures consolidated by hydrogen bonding and π-π interaction

The amidation of aliphatic amine with acryloyl chloride in dry benzene as a solvent has been performed. Moreover, the polymer complexes have been prepared and structurally characterized by analyses, molar conductance measurements, magnetic susceptibility measurements, spectral techniques like IR, UV, NMR, ESR and thermal methods. Acryloyl hydrazine (AH) has been shown to behave as a bidentate ligand via its nitrogen (NH(2) of hydrazine group) and C-O/C=O (acryloyl group) in polymer complexes, all of which exhibit supramolecular architectures assembled through weak interaction including hydrogen bonding and π-π stacking .The magnetic and spectral data indicate a square planar geometry for Cu(2+) complexes and an octahedral geometry for Co(II) and UO(2)(II). The ESR spectral data of the Cu(II) complexes showed that the metal-ligand bonds have considerable covalent character. The thermal stability was investigated using thermogravimetric analysis. The results showed that the polymer complexes are more stable than the homopolymer.

Structural and characterization of novel copper(II) azodye complexes

The synthetic methods of novel Cu(II) and adduct complexes, with selective azodyes containing nitrogen and oxygen donor ligands have been developed, characterized and presented. The prepared complexes fall into the stoichiometric formulae of [Cu(L(n))(2)](A) and [Cu(L(n))(2)(Py)(2)](B), where two types of complexes were expected and described. In type [(A) (1:2)] the chelate rings are six-membered/four coordinate, whereas in type [(B) (1:2:2)] they are six-membered/six coordinate. The important bands in the IR spectra and main (1)H NMR signals are tentatively assigned and discussed in relation to the predicted assembly of the molecular structure. The IR data of the azodye ligands suggested the existing of a bidentate binding involving azodye nitrogen and C-O oxygen atom of enolic group. They also showed the presence of Py coordinating with the metal ion. The coordination geometries and electronic structures are determined from the framework of the proposed modeling of the formed novel complexes. The complexes (1-5) exist in trans-isomeric [N,O] solid form, while adduct complexes (6-10) exist in trans isomeric (Py) form. The square planar/octahedral coordination geometry of Cu(II)/adduct is made up of an N-atom of azodye, the deprotonated enolic O-atom and two Py. The azo group was involved in chelation for all the prepared complexes. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(L(n))(2)]. The ligands in the dimmer are stacked over one another. In the solid state of azo-rhodanine, the dimmers have inter- and intramolecular hydrogen bonds. Interactions between the ligands and Cu(II) are also discussed.

Stereochemistry of new nitrogen containing heterocyclic compound XII. Polymeric uranyl complexes of hydrazone compounds

Several dioxouranium(VI) heterochelates with tetradentate monobasic hydrazone compounds (HL(n)) have been synthesized. The heterochelates of the type [(UO2)2(HL(n))(L(n))2(OAc)2(OH2)2]n have been characterized on the basis of elemental analyses, IR and electronic spectra, conductance and magnetic susceptibility measurements. The complexes are polymeric, non-electrolytes, diamagnetic and eight-coordinated. Wilson, G.F. matrix method, Badger's formula, Jones and El-Sonbati equations were used to determine the stretching and interaction force constants from which the U-O bond distances were calculated. The bond distances of these complexes were also investigated.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. Part XI. Novel ligational behaviour of quinoline as chelate ligand toward transition metal ions

Novel complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and UO2(II) with a new Schiff base derived from 8-hydroxy-7-quinolinecarboxaldehyde and 2-aminoethanethiol (LH2) (system name: 2-(8-hydroxy-7-carboxalimino)ethanethiol.) have been prepared and characterized on the basis of analytical, thermal, magnetic moment, infrared, electronic, NMR and EPR spectral data. From the analytical, NMR and thermal data and stoichiometry of the complexes indicate that LH2 act as a dibasic tridentate ligand with ONS donors towards all the metal ions. The magnetic moment, electronic and EPR spectral data commensurate that the Mn(II), Fe(II), Ni(II) and UO2(II) complexes are dimeric with octahedral configuration while the Cu(II) and Zn(II) complexes are monomeric with square-planar and tetrahedral geometries, respectively. Various ligand field parameters Dq, B and beta for complex 5 was calculated. The complexes 3+4 have lower symmetries and the amount of distortion in terms of DT/DQ applying NSH "Hamiltonian Theory" has been evaluated which indicate that the complexes are moderately distorted.

Polymer complexes. XXXX. Supramolecular assembly on coordination models of mixed-valence-ligand poly[1-acrylamido-2-(2-pyridyl)ethane] complexes

The build-up of polymer metallic supramolecules based on homopolymer (1-acrylamido-2-(2-pyridyl)ethane (AEPH)) and ruthenium, rhodium, palladium as well as platinum complexes has been pursued with great interest. The homopolymer shows three types of coordination behaviour. In the mixed valence paramagnetic trinuclear polymer complexes [(11)+(12)] in the paper and in mononuclear polymer complexes (1)-(5) it acts as a neutral bidentate ligand coordinating through the N-pyridine and NH-imino atoms, while in the mixed ligand diamagnetic poly-chelates, which are obtained from the reaction of AEPH with PdX2 and KPtCl4 in the presence of N-heterocyclic base consisting of polymer complexes (9)+(10), and in monouclear compounds (6)-(8), it behaves as a monobasic bidentate ligand coordinating through the same donor atoms. In mononuclear compounds (13)+(14) it acts as a monobasic and neutral bidentate ligand coordinating only through the same donor atoms. Monomeric distorted octahedral or trimeric chlorine-bridged, approximately octahedral structures are proposed for these polymer complexes. The poly-chelates are of 1:1, 1:2 and 3:2 (metal-homopolymer) stoichiometry and exhibit six coordination. The values of ligand field parameters were calculated. The homopolymer and their polymer complexes have been characterized physicochemically.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. VIII. Spectral and coordination modes of mixed-ligand of novel ruthenium(III) complexes

Reaction of 8-hydroxy-7-quinolinecarboxaldehyde (LH) with RuC3 x XH2O afforded the compounds [RuL3] and/or [RuL2CIOH2]. Reactions of LH with RuCl3 x XH2O in the presence of N-heterocyclic bases led to the formation of complexes of type [RuL2 x ClPy] and [RuLCl2(o-Phen)] (Py = pyridine or o-Phen = 1,10-phenanthroline). The amine exchange reactions of coordinated Schiff bases in these complexes have been also carried out which give symmetrical tetradentate Schiff base complexes. These complexes were characterized by a combination of elemental analysis, IR, magnetic susceptibility measurements, 1H, 13C NMR and electronic spectral analysis methods. The spectral data were utilized to compute the important ligand field parameters B, beta and Dq. Electronic spectra show all complexes are octahedral. The B-values suggest a strong covalency in the metal-ligand sigma-bond and the Dq-values indicate a medium-strong ligand field. The stereochemistry and the nature of the complexes are markedly dependent upon the molar ratios of the reactants, the pH of the system and the nature of the anions involved. The ligands behave as bi-(0,0) and tetradentate (N2,O2) donors.

Substituents effect on the spectral studies on rutheninum(III) complexes of 5(-4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone

A novel series of Ru(III) complexes with 5(-4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone (HLn) have been prepared. The ligands and structural composition of complexes were confirmed and characterized by various physico-chemical techniques. The spectral data were utilized to compute the important ligand field parameters B, beta and Dq. The effect of Hamett's constant on the ligand field parameters is also discussed. The spectral and magnetic results commensurate an octahedral environment around the Ru(III) ion. The B-values suggest a strong covalency in the metal-ligand sigma-bond and the Dq-values indicate a medium-strong ligand-field. IR spectra show that the ligand is neutral bidentate forming thereby a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. The ligands are present in associated form in solution via intermolecular hydrogen bond and act as neutral bidentate coordinated to ruthenium(III).

Stereochemistry, structural and models of novel 5-(4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone complexes

Copper(II) and cadmium(II) complexes of 5-(4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone (HLn) were prepared, their compositions and physicochemical properties were characterized by elemental analysis, magnetic suseptibility measurements, and infrared, electronic spectra. The novel complexes have the stoichiometric formulae [Cu(HLn)(OAc)n(H2O)(X)] (OAc = acetate, X = H2O or acetate) and [Cd(L)(OAc)(H2O)], respectively. Elemental analysis and IR spectra denote, that two types of complexes with different octahedral and tetrahedral structure for Cu(II) and Cd(II) ions. I.R. spectra show that the ligand is monobasic/neutral bidentate forming thereby a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. The stoichiometeries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes.

Polymer complexes XXXVII novel models and structural of symmetrical poly-Schiff base on heterobinuclear complexes of dioxouranium(VI)

Some binary and ternary novel complexes of dioxouranium(VI) with 5-vinylsalicylaldehyde (VSH) have been prepared and characterized by various physico-chemical techniques. The amine exchange reactions of coordinated poly-Schiff bases in these complexes have been also carried out which give symmetrical tetradentate poly-Schiff base complexes. Metal exchange reaction of these dioxouranium(VI) complexes with copper(II) gives the corresponding Cu(II) complexes. Reaction of tetradentate poly-Schiff base complexes of Cu(II) so obtained with ZrCl4 gives heterobinuclear polymer complexes. Magnetic, electronic and IR spectral information commensurate that configurations of square planar copper(II) polymer complexes. All the polymer complexes are coloured and appear to be nonelectrolytes in DMF. The ligands behave as bi-(O, O) and tetradentate (N2, O2) donors. El-Sonbati equation was used to evaluate the symmetric stretching frequency from which the fU-O and fUO, UO- were calculated.

Temperature and substituent effects on the dissociation constants of 5-azorhodanine derivatives. Semi-empirical quantum mechanical calculation

Detailed analysis of the electronic structure and properties of some rhodanine derivatives (RDs) is presented. The aim of the present investigation is to pinpoint the electronic structural similarities and differences, among the series of the studied RDs that govern and determine their acidic, basic and co-ordinative properties. The geometries of the studied rhodanine were fully optimized at the level of AMI semi-empirical method. Relative stabilities of the enol/keto isomers have been calculated. Proton affinities and proton detachment energies were computed for the series of rhodanine studied, at the level of AM1 method and compared with the potentiometrically-determined proton-ligand dissociation constants. Zero-point energy and electron correlations have been taken into consideration. pK(H) have been found to increase with increasing electron-donating nature of the substituents. The resulting linear Hammett plots of pK(H) versus the Hammett constant sigma values indicate the co-planarity of the investigated molecules. The evaluated thermodynamic parameters (deltaG, deltaH and deltaS) indicate that the dissociation processes are non-spontaneous, endothermic and entropically unfavourable.

Coordination modes of novel rhodanine azodye complexes

The reaction products of metal(II) salts with 5-sulphamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone (H2L) have been characterized by elemental analyses, magnetic susceptibility, electronic, infrared and electron paramagnetic resonance spectral measurements. The spectral data suggest a square pyramidal structure for Cu(II) and Co(II) complexes and an octahedral for Ni(II) complexes. Various EPR parameters have been calculated. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated. In all case kperpendicular > kparallel which indicates a 2B1g ground state. These five coordinated complex of Cu(II) react further with pyridine forming six coordinate base adduct. The different modes of chelation of the ligand and stereochemistry around the metal ion are discussed.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. VII. Potentiometric, conductometric and thermodynamic studies of novel quinoline azodyes and their metal complexes with some transition metals

A novel series of quinoline azodyes (5-(4'-derivatives phenyldiazo)-8-hydroxy-7-quinolinecarboxaldehyde)) (HL1-HL5) has been prepared and characterized by elemental analyses, 1H-NMR and IR spectra. The IR spectral data indicate that the compounds can exist in two resonance structures. Proton-ligand dissociation constants of quinoline azodyes and their subsituted derivatives, and metal-ligand stability constants of their complexes with bivalent (Mn2+, Co2+, Ni2+, Cu2+) metal ions have been determined potentiometrically in 0.1 m KCl and 40% (v/v) dimethylformamide (DMF)-water mixture. The influence of substituents on the dissociation and stability constants was examined on the basis of the electron repelling property of the substituent. The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied and the corresponding thermodynamic parameters (deltaG, deltaH, deltaS) were derived and discussed. The stoichiometries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes was indicated.

Thermodynamics of substituted pyrazolone IX: potentiometric, spectrophotometric and conductometeric studies of 4-(4-chlorophenylazo)-3-methyl-1-[2-hydroxy-3-morphilinopropane 1-yl]-2-pyrazolin-5-one and its metal complexes

The dissociation constants of 4-(4-chlorophenylazo)-3-methyl-1-[2-hydroxy-3-morphilinopropane-1-yl]-2-pyrazolin-5-one (CAMP) has been determined potentiometrically in 0.1 M KCl and 40% (v/v) ethanol-water mixture. The stepwise stability constants of the formed complexes of Mn2+, Co2+, Ni2+, Cu2+, Zn2+, La3+, Ce3+ and UO(2)2+, with CAMP have been determined. The stability of the formed complexes were found as follows: UO(2)2+ > Ce3+ > La3+ > Mn2+ < Co2+ < Ni2+ < Cu+ > Zn2+. The thermodynamic parameters (deltaG, deltaH and deltaS) for CAMP and its complexes were evaluated and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavourable. The formation of the complexes have been found to be spontaneous, exothermic or endothermic (depending on the metal) and entropically favourable. The stoichiometries of these complexes were determined spectrophotometrically and conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes.

Spectral studies on metal-ligand bonding of novel rhodanine azodye sulphadrugs

A series of novel complexes with 5-sulphadiazineazo-3-phenyl-2-thioxo-4-thiazolidinone (H2L1) and 5-sulphamethazineazo-3-phenyl-2-thioxo-4-thiazolidinone (H2L2) and various anions were prepared. Their structures and properties were characterized by elemental analyses, IR, UV-vis, EPR spectroscopy and magnetic measurements. The visible and EPR spectral studies indicated that the Cu(II) complexes have distorted octahedral. From the electron paramagnetic resonance and spectral data, the orbital reduction factors k(parallel) and k(perpendicular) were calculated. In all cases k(perpendicular) > k(parallel) indicates a 2B1g ground state. The crystal field parameters for Co(II) and Ni(II) complexes were calculated. The electronic absorption and a g(parallel)/A(parallel) values are indicative for the beginning of tetragonal distortion. The complexes, however, have lower symmetries and the amount of distortion in terms of DT/Dp, applying NSH 'Hamiltonian Theory' has been evaluated which indicate that the complexes are moderately distorted.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. VI. Novel structural and properties models of uranyl with quinoline azodyes

A novel series of UO2(2+) complexes with 5-(4'-derivatives phenyldiazo)-8-hydroxy-7-quinolinecarboxaldehyde (L1H-L7H), have been prepared. The composition and structure were confirmed by elemental analyses, 'HNMR spectra and IR spectroscopy measurements. Data from the above show that they exist in two isomeric solid forms. The polymeric structure results from intermolecular U=O...U=O interactions. The ligands act as a monobasic bidentate chelating agent coordinating through C=O and OH groups by replacement of a proton from the latter group. The force constant F(U-O) (mdyn A(-1)) and the bond length R(U-O) (A) of the U-O bond were calculated from the IR data and related to the electronic properties of the substituents. The existing literature on the coordination chemistry of these ligands are obscure.

Structural and models of dioxouranium(VI) with rhodanine azodyes--V

The synthesis of several new coordination compounds of dioxouranium(VI) heterochelates with bidentate rhodanineazol compounds derived from rhodanine are described. The ligands and uranyl complexes have been charcaterized by various physico-chemical techniques. The bond lengths and the force constants have been calculated from asymmetric stretching frequency of O-U-O group. The infrared spectral studies showed a monobasic bidentate behaviour with the oxygen and azonitrogen donor system. The ligands contain intramolecular hydrogen bonds.