The new oxovanadium(V) complex, [VO(acac)(dametsc)] ( 1 ) (acac = acetylacetonate (-1), H 2 dametsc = diacetylmonoxime-4-ethylthiosemicarbazone), has been prepared and characterized by studying its physicochemical properties. The X-ray crystal structure of the complex ( 1 ) has been determined and showed the presence of vanadium(V) atom in a unique heptacoordination state with distorted pentagonal bipyramidal geometry. The oximato ligand in the pentagonal plane is bonded to the central vanadium atom in dihapto (η2= N,O) manner with the formation of three membered ring, while the other three coordination sites in the plane are occupied by hydrazinic imine nitrogen, thiolate sulfur, and one of the acac oxygen atoms. The axial position sites are defined by the other acac oxygen and the trans oxo-atom. The supramolecular structure of the complex is exclusively constructed by intermolecular interactions, N–H⋯O and C–H ⋯ O.
In the present work, we report the fabrication of silica nanoparticles embedded polymeric (SiO 2 nanoparticles@polymer) composite films for numerous traits like texture, folding endurance, crystallinity, size, thermal behavior, spectral analysis, and bioactivity. Significant facets of bulky, inert, inorganic materials are known to burgeon out due to the high surface area of nanosized particles. Nature and proportion of silica nanoparticles as well as polymers exhibited remarkable impact on the fabrication and quality of casted films. Hydrophilic silica nanoparticulate-PVA films depicted better mechanical properties like thermal plus photo stability. Hydrophobic silica nanoparticulate-PMMA films showed qualities of a robust, active, thermostable, antimicrobial material that could resist extreme storage and processing conditions. Overall, these metal oxide nanoparticle-polymer composite films possess qualities reflecting their potential in food, pharmaceutical, and cosmetic industry.
Two new polypyridyl complexes [Ru(ttp)(L 1 )Cl]PF 6 ( 1 ) and [Ru(ttp)(L 2 )Cl]PF 6 ( 2 ) with noninnocent o-benzoquinonediimine (L 1 ; bqdi) and 4,5-dimethyle-o-benzoquinonediimine (L 2 ; 4,5-di-Mebqdi) ligands were synthesized and characterized (ttp = -p-toloyle-2,: ,-terpyridine). Cyclic voltammetry studies suggest that noninnocent ligands are coordinated in their benzoquinonediimine form. Preliminary ruthenium complexes-induced DNA dysfunction was studied on E. coli GM109 DNA by means of melting temperature analysis (Tm). Our results suggest that complex ( 2 ) inhibited DNA function more strongly compared to ( 1 ). Antibacterial activities of the complexes against E. coli bacteria were studied, and Minimum inhibitory concentration (MIC) values were evaluated. Both complexes showed great antibacterial activities.
Three new Ni(II) square planar complexes of 4-methoxy-3-benzyloxybenzaldehyde thiosemicarbazide(4m3BTSC) having polypyridyl bases of general formulation [ML 2 ] ( 1 ) and [MLB] ( 2 , 3 ), where L = 4m3BTSC and B is N,N-donor heterocyclic bases, namely, 1,10-phenanthroline (phen, 2 ), 2,2′-bipyridine (bpy, 3 ), are synthesized and characterized. The free radical scavenging assay results showed that complex 1 possesses significant activity when compared to complexes 2 and 3 . The biological studies showed that the ligand and its complexes exhibited significant and different biological activities and also the prepared compounds are nonmutagenic. They may be potential commercial antioxidants because of their nonmutagenic and nontoxic nature. The DNA interaction of the new complexes is evaluated by absorption, emission, and melting temperature methods, and the results suggested that the binding affinity of the complexes increases with the presence of planar ligand in the molecule. The nickel (II) complexes with planar phenanthroline bases show moderate DNA binding and cleavage ability.
The complex formation equilibria between Ag(I) and thiourea (Tu), N methyl-Thiourea (MeTu), N,N′-dimethyl-Thiourea (Me2Tu), N,N,N′,N′ Tetramethyl-Thiourea (Me4Tu), N-ethyl-Thiourea (EtTu), N,N′ diethyl-Thiourea (Et2Tu), and N,N′-Ethylen-Thiourea (EnTu) in propan-2-ol as solvent medium have been investigated by potentiometry within the temperature range 10°C–40°C and self-determined ionic medium by (AgNO3) concentration range 6.36·10-6–3.83·10-5 m·dm−3 (no background electrolyte added). The experimental results can be interpreted with the stepwise formation of tris-coordinated complexes AgLn (n=1–3; hereafter charge is omitted). The stability constants log βn and the standard thermodynamic changes in enthalpy (ΔHn°) and entropy (ΔSn°) for overall complex formation reactions AgI+nL=AgLn (n=1–3) have been evaluated. The reactions are exothermic in nature and entropy disfavored for all the investigated ligands. The standard enthalpy and entropy changes for the stepwise reactions AgLn-1+L=AgLn have been evaluated by difference ΔΔHn°=ΔHn°-ΔHn-1° and ΔΔSn°=ΔSn°-ΔSn-1°. The stepwise enthalpy are mutually linearly related to the corresponding entropy changes with isoequilibrium temperatures Tiso=285, 305, and 363 K for n=1, 2, or 3 respectively.
The present paper reports a computational investigation of potential communication between the lysine tyrosylquinone (LTQ) and copper cofactors within lysyl oxidase (LOX). Various substrates and inhibitors of LOX were docked into the active site in our computer generated model of the enzyme. Conformational changes in the vicinity of the copper site as well as changes in the electrostatic environment were identified. The appearance of a canal-like structure involving tyrosine 35 (TYR35) and glutamine 104 (GLN104) residues was shown to be consistent upon docking of a variety of different compounds. Interactions between LOX and its natural substrate, collagen, were also explored through molecular dynamic simulations. The possibility of communication between the organic and inorganic cofactors in LOX was proposed, aiding the ongoing debate regarding the role of copper in the catalytic mechanism of this important enzyme.
Organic salts of cobalt were synthesized in the presence of amine, ethanol, and ethyl methyl ketoxime and were used as drier for alkyd resin. Considering the drying time of alkyd resin containing synthesized compound showed that amines, as electron releasing groups (ERG), increased the oxidizing activity of drier and shortened drying time about an hour, whereas ethyl methyl ketoxime delayed the drying of resin 2 hours. Two methods of synthesis, including solution and precipitation processes of synthesis, were compared in terms of convenience, cost, and environmental aspects.
A new cobalt(II) complex [Co(dppz) 2 (4,7-dmp)] 2+ (4,7-dmp = 4,7-dimethyl-1,10-phenanthrolline) and dppz = dipyrido[3,2- a :2′-3′- c ]phenazine has been synthesized and characterized by elemental analysis (CHN), FT-IR, and UV-visible (UV-Vis) spectroscopic techniques. The DNA-binding property of the complex has been investigated employing absorption spectroscopy, fluorescence spectroscopy, circular dichroism, and viscosity measurements. The experimental results show that the complex can bind to DNA in an intercalation mode. In comparison with previous study, the DNA-binding affinity of [Co(dppz) 2 (4,7-dmp)] 2+ (Kb=1.1·106 M −1 ) is smaller than that of complex [Co(dppz) 2 (2,9-dmp)] 2+ (Kb=2.5·106 M −1 ).
The copolymerization of ethene and carbon monoxide can be catalyzed with square planar arenidotriphenylphosphane nickel(II) complexes containing an N,O -chelate ligand. To examine the influence of the phosphorus ligand on the catalytic activity, five new nickel(II) complexes with P -ligands of different basicities and different steric demands were synthesized and fully characterized including the determination of the crystal structures of three of the complexes. The investigation of the catalytic activity of the new compounds showed a decisive influence of the steric properties of the P -ligand. A minimum steric demand is essential to ensure catalytic activity.
We have previously proposed a simple empirical equation to reproduce the literature values of the ionization energies of one-electron to four-electron atomic ions with very good agreement. However, we used a potential energy approach in our equation, which has no theoretical basis. This paper discusses an alternative kinetic energy expression for one to five electrons with simple corrections for relativistic and Lamb shift effects and for two- to-five electron ions additional effects including electron relaxation and residual interactions. For calculated values of one-electron (hydrogen-like) and two electron (helium like) atomic ions, the difference with the literature values is typically 0.001% or less. Agreement with the literature values for three-, four-, and five-electron ions is 99% or better. First electron affinities calculated by our expression also agree fairly well with generally recommended values. These results show that there is strong evidence that our methodology can be developed to reliably predict, with fairly good accuracy, ionization energies of multielectron atomic ions that have not been measured.
Low temperature syntheses of zinc oxide and cadmium oxide nanoparticles are reported in this paper. The inorganic precursor complexes were prepared and characterised by hydrazine and metal analyses, infrared spectral analysis, and thermal analysis. Using appropriate annealing conditions, zinc oxide and cadmium oxide nanoparticles of average particle sizes around 13 nm and 30 nm were synthesised from the precursors by a simple thermal decomposition route. The synthesised nanoparticles were characterised for their size and structure using X-Ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and scanning electron microscopy (SEM) techniques.
Potato-based starch was dissolved in distilled water until paste form of starch was found. Paste form of starch polymer by the process of polycondensation reacted with an essential amino acid lysine in a basic medium. The viscous product obtained was then filtered and after a short period of drying was then coordinated with a series of transition metals as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The synthesized polymeric ligand and its polymer metal complexes were spectroscopically characterized, thermally analyzed, and biologically evaluated. In this work, FT-IR, 1H-NMR, 13C-NMR, CHN, TGA, SEM, antimicrobial screening, and ASTM- D5338-93, a CO2 evolution method of biodegradable, studies were carried out. The confirmation of the synthesis was done with these instrumental and spectroscopic techniques. Metals-coordinated polymer complexes were found to be more thermally stable and less biodegradable than the virgin parent ligand. Metal-coordinated polymers of all metals were found to be antibacterial and antifungal, with a range of weak to mild zone of inhibition values in agar well diffusion method for antimicrobial studies. Cu(II) polymer metal complex showed the highest value of antimicrobial activity because of the highest stability constant.
Binary complexes of Cu(II), Ni(II), and Zn(II) ions have been synthesized by reacting metal salts with a Schiff base, 2-((E)-(5-methylisoxazol-3-ylimino)methyl)-4-methoxyphenol (MIIMMP) in an alcoholic medium. All the metal complexes and schiff base have been characterized by using elemental analysis, IR, UV-VIS, 1 H-NMR, 13 C-NMR, Mass, ESR spectral data, magnetic moments, TG, and DTA studies. Based on the analytical, spectral data and molecular modeling studies, Ni(II) and Zn(II) metal complexes have octahedral geometry, whereas Cu(II) complex has tetragonal geometry. The antimicrobial and cytotoxic activities of the Schiff base and its metal complexes were studied on bacteria, fungi, and human cervical carcinoma cells (HeLa).
Decreasing the size of oxide particles to nanoscale enables one to ensure maximal reaction rates and depths in the solid due to the enhancement of the specific surface area and the increase of the diffusion rate caused by shortening diffusion paths. For that reason, one may suggest that in the case of adsorption onto nanoparticles, the complete conversion of sorbents to stoichiometric compounds would become possible. Adsorption of phosphate ions onto nanosized hematite supported on silica gel surface has been studied. Modification of silica gel surface by hematite in the quantity of 0.62 and 1.25 mass% has been carried out by means of a citric acid aided method. The morphology of the samples obtained has been characterized using DTA, XRD, SEM, and low temperature desorption of nitrogen. It has been found in batch experiments that unlike natural and synthetic hematites, for which the limiting adsorption values do not exceed 14 mg/g, silica gel supported nanosized hematite adsorbs 400–2000 mg of the phosphate ions per gram, thus forming near-stoichiometric iron phosphates on the surface of the support. The degree of conversion of hematite to iron phosphates is greater in acidic media and at a lower surface coverage, when hematite crystallites are small and better accessible by adsorbate.
Complexes of Fe(III) and Mn(II) with bithiourea were synthesized and characterised by elemental analysis, magnetic measurements, infrared spectroscopy, UV/visible, thin layer chromatography, and conductance measurements. The IR showed that the ligand coordinates through C=S and N–H donor atoms and hence a bidentate. The antimicrobial activity of the complexes formed has been tested and compared with bithiourea at different concentrations in order to obtain some quantitative information about their biological activity towards microorganism. Metal complexes were found to show better activities as compared to the ligand and the standard drug used as control.In vivotoxicological studies showed that the complexes were not toxic at the dosage level administered.
This paper deals with the syntheses and structural features of some new diorganosilicon(IV) and diorganotin(IV) complexes having general formulae (CH3)2MCl(L1), (CH3)2MCl(L2), (CH3)2M(L1)2, and (CH3)2M(L2)2 with new Schiff bases (M = Si and Sn). The Schiff bases HL1 and HL2 have been derived from the condensation of 3-bromobenzaldehyde with 4-amino-3-ethyl-5-mercapto-1,2,4-triazole and 4-amino-5-mercapto-3-propyl-1,2,4-triazole, respectively. The compounds have been characterized by the elemental analyses, molar conductance, and spectral (UV, IR, 1H, 13C, 29Si, and 119Sn NMR) studies. The resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. In vitro antimicrobial activities of the compounds have been carried out.
The present paper gives an overview of the hydrolysis reactions up to colloid formation of Bi(III) in aqueous nitric acid medium using light-scattering measurements. The hydrolysis products of Bi were polynuclear complexes such as dimers, pentamers, and the most important is the hexameric species. In the present investigation Bi3+ polymers were prepared by diluting different concentrations of Bi(NO3)3·5H2O solutions to pH 1 ± 0.1 by adding 0.1 M NaOH solution as it starts to precipitates at pH 1.4. The degree of polymerization was found to be 5-6 units. Particle size measurements were performed, and it has been found that particle size increases at high concentration of Bi due to aggregation. Refractive index measurements were also performed. The molecular weight of hydrolyzed polymeric species of Bi was determined by using Debye plot, and it was estimated as 1236 Da. The second virial coefficient was found to be 6.24 × 10−3 mLg−1 Da. The present investigation confirms that the predominant complex in the solution has 5-6 Bi atoms.
The syntheses of new oxovanadium(IV) complexes having general formula [VO(mac)]SO4 have been carried out by using in situ method of preparation where vanadyl ion acts as kinetic template for the ligands derived by condensation of 2,2′-pyridil with 1,2-diaminopropane and 1,3-diaminopropane. The complexes were characterized by elemental analyses, molar conductance, magnetic moments, and spectral (infrared, electronic, and electron spin resonance) data. All the oxovanadium(IV) complexes are five coordinate wherein derived ligands act as tetradentate chelating agents.
The new binuclear niobium(V) complexes of the type [[NbO(L)C4H4O6]2C4H4O6] (where L = DMH, IMH, IPH, FPH, TMT) were prepared with biologically important drugs and characterized by using elemental analysis; IR, 1H-NMR, and UV-Vis spectral studies, and thermogravimetric analysis. The molar conductance measurement of all the complexes in DMF solution corresponds to 1 : 1 electrolytic nature. All complexes were of the pure diamagnetic character and were found to have six-coordinate octahedral geometry. The antimicrobial activity of these complexes has been screened against two Gram-positive and two Gram-negative bacteria. Antifungal activity against two different fungi has been evaluated and compared with controls. All the complexes inhibit the growth of both Gram-positive and Gram-negative bacteria to a competent level.
The synthesis, spectroscopic, and magnetic characterization of two new copper(II) and cobalt(II) complexes are described. Both two compounds have the general formula [M(L)2(Cl)2] (M = Cu (I), Co (II); L = 2-amino-5-bromopyridine). These complexes were prepared in one-step synthesis and characterized by elemental analysis, FT-IR, UV-Vis, and EPR spectroscopy. Moreover, the single crystal structure of complex I was studied by the X-ray diffraction method. This compound consists of mononuclear units consisting of two ligands linked to metal via the nitrogen of pyridine ring. The UV-Vis spectra of copper(II) and cobalt(II) complexes show three and five absorption bands, respectively, attributed to the d-d transition of the metal ion, ligand → metal charge transfer and π → π* or n → π* transitions of the ligand. The FT-IR spectra show MN2Cl2 vibrations at 500–300 cm−1. The complexes show room temperature magnetic moments of 1.78 and 4.12 μB for Cu(II) and Co(II), respectively. The X-band electron spin resonance (ESR) spectra of Cu(II) complex in DMF or DMSO frozen at liquid nitrogen temperature show the typical ΔMS = ±1 transition.
