Exchange Interaction in Complex Bis[(1,3-Dithiole-2-Thione-4,5-Dithiolato)-di-(Carbonyl)-Cyclopentadienyl Iron(II)]

The splitting of the quasidegenerate electronic states in dinuclear bis[(1,3-dithiole-2-thione-4,5-dithiolato)-di-(carbonyl)-cyclopentadienyliron (II)] complex with the bridging, S–S coupled, dimerized sulfur-rich dithiolate ligands, [Fe(C5H5)(CO)2(C3S5-C3S5)Fe(C5H5)(CO)2] (I) was found by the means of Mössbauer spectroscopy and by the measurement of the temperature dependence of magnetic susceptibility in a wide temperature range from 2 K to 300 K. The experimental results were confirmed by the calculations of the singlet and triplet states of the complex, as well as of the distribution of spin density within the bounds of the DFT method in the B3LYP/6-31(dp)G basis. In the more stable triplet state, the spin density is significantly delocalized, which is a characteristic of olefindithiolate complexes.

Antifungal and Spectral Studies of Cr(III) and Mn(II) Complexes Derived from 3,3′-Thiodipropionic Acid Derivative

The Cr(III) and Mn(II) complexes with a ligand derived from 3,3′-thiodipropionic acid have been synthesized and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, IR, UV, and EPR spectral studies. The complexes are found to have [Cr(L)X]X2 and [Mn(L)X]X, compositions, where L = quinquedentate ligand and X=NO3−, Cl− and OAc−. The complexes possess the six coordinated octahedral geometry with monomeric compositions. The evaluated bonding parameters, Aiso and β, account for the covalent type metal-ligand bonding. The fungicidal activity of the compounds was evaluated in vitro by employing Food Poison Technique.

Synthesis and Characterization of Biologically Active 10-Membered Tetraazamacrocyclic Complexes of Cr(III), Mn(III), and Fe(III)

A new series of macrocyclic complexes of type [M(TML)X]X2; where M = Cr(III), Mn(III), or Fe(III); TML is tetradentate macrocyclic ligand and X = Cl−1, NO3−1, CH3COO−1 for Cr(III), Fe(III), and X = CH3COO−1 for Mn(III) has been synthesized by template condensation of succinyldihydrazide and glyoxal. The complexes have been formulated as [M(TML)X]X2 due to 1:2 electrolytic natures of these complexes as shown by conductivity measurements. The complexes have been characterized with the help of elemental analyses, molar conductance, electronic, infrared, far infrared spectral studies and magnetic susceptibilities. On the basis of these studies, a five-coordinate distorted square-pyramidal geometry, in which two nitrogens and two carbonyl oxygen atoms are suitably placed for coordination toward the metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activities against some selected bacterial strains. The minimum inhibitory concentration shown by these complexes was compared with minimum inhibitory concentration shown by some standard antibiotics like linezolid and cefaclor.

Kinetic and Mechanistic Studies on the Reaction of DL-Methionine with in Aqueous Medium at Physiological pH

The reaction has been studied spectrophotometrically; the reaction shows two steps, both of which are dependent on ligand concentration and show a limiting nature. An associative interchange mechanism is proposed. Kinetic and activation parameters ( and ) and (, , , and ) have been calculated. From the temperature dependence of the outer sphere association equilibrium constant, thermodynamic parameters ( and ; and ) have also been calculated.

Crystal Structure of [Bis(L-Alaninato)Diaqua]Nickel(II) Dihydrate

The title complex, [Ni, has been prepared from nickel(II) chloride in aqueous solution by adding L-alanine and potassium hydroxide. It has been crystallized from aqueous solution, and its structure was determined by X-ray structure analysis. The nickel(II) ion adopts distorted octahedral coordination geometry with two bidentate L-alanine molecules and two water molecules. The complex is neutral and dihydrated. The crystal structure shows the hydrogen bonding between water and amide hydrogens within the lattice, and each fragment of the complex contains two water molecules as hydrated water. The L-alaninato ligand skeleton of the compound adopts the most stable trans-III configuration in the solid state. The alternating two five-membered chelate rings are in the stable gauche conformation.

Mean Amplitudes of Vibration of the IF8 − Anion

The mean amplitudes of vibration of the interesting IF8 − anion (D4d-symmetry), containing iodine (VII), were calculated from known spectroscopic and structural data in the temperature range between 0 and 1000 K. The results are discussed in comparison with those of related species.

Kinetic and Mechanistic Study of the Reduction of Chromium(VI) by Lactic Acid

The kinetics and mechanism of the reduction of chromium(VI) by lactic acid (Lac) in aqueous acidic medium was studied with spectrophotometry in a temperature range of 298.15 K~313.15 K. Under the conditions of the pseudo-first order , the observed rate constant increased with the increase in [Lac] and . There is no salt effect. Based on the experimental results, a probable reaction mechanism of oxidation was proposed. The rate equation derived from the mechanism could explain all the experimental phenomena. Activation parameters along with rate constant of the rate-determining step have been evaluated.

Nickel(II) Complexes of Hydrazone of Isoniazid and Their Magneto-Spectral, Electrochemical, Thermal and Antimicrobial Investigations

The synthesis of novel nickel(II) complexes with new ligand derived from hydrazone of isoniazid has been reported. The complexes have general compositions [Ni(L)2X2] or [Ni(L)3](ClO4)2, where L = N-isonicotinamido-furfuraldimine (INH-FFL) and X=Cl− or NCS−. The ligand hydrazone behaves as neutral bidentate (N and O donor) through the carbonyl oxygen and azomethine nitrogen. On the basis of elemental analysis, molecular weight determinations, magnetic susceptibility/moment, thermogravimetric, electrochemical, and spectroscopic studies, the new complexes have been characterized with octahedral geometry. The antibacterial and antifungal studies of the present complexes show that they are moderate antibacterial and antifungal agents.

Molybdenum and Tungsten Tricarbonyl Complexes of Isatin with Triphenylphosphine

Reaction of M(CO)6; M = Mo or W with isatin in the presence of triphenylphosphine in THF under reduced pressure gave the tricarbonyl derivatives complexes [M(CO)3(isatH)(PPh3)]. The two complexes were characterized by elemental analysis, infrared, mass and 1H NMR spectroscopy. The spectroscopic studies show that the two complexes exist in fac- and mer-isomers in solutions through exchange the CO group and PPh3. The Uv-Vis spectra of the complexes in different solvents were studied.

Synthesis and Characterization of Boehmite Nanofibers

Boehmite nanofibers of high quality were synthesized through a wet-gel conversion process without the use of a surfactant. The long nanofibers of boehmite with clear-cut edges were obtained by steaming the wet-gel precipitate at 170∘C for 2 days. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared emission spectroscopy (IES), as well as Raman spectroscopy were used to characterize the products.