Synthesis and spectral studies of the biologically active complexes of tantalum(V) with N-alkylphenothiazines

Dioxo-bridged binuclear tantalum(V) complexes with six N-alkylphenothiazines (NAP) of general formula [TaO(L)(C2O4)]2C2O4, (L=NAP) have been prepared and characterized on the basis of elemental analysis, conductometric, magnetic and thermogravimetric data. The spectra of the complexes indicate that both the phenothiazine ligands and oxalate groups are coordinated to tantalum in a bidentate fashion, suggesting a coordination number of six around metal. The fungitoxicity of the isolated complexes against several fungi has been investigated.     

Palladium(II) complexes ofN-alkyl phenothiazines

Summary Eight square-planar palladium(II) complexes, PdLCl₂ (L=N-alkyl phenothiazine) have been synthesized. Analytical, conductometric, spectral (electronic, i.r. and n.m.r.) and thermal data for the complexes have been discussed.Part of the paper presented at the International Conference The Chemistry of the Platinum Group Metals, Bristol July 20–24th, 1981.     

Vibration characteristics of a bi-density drumhead

The dayan tabla is a percussion instrument used as an accompaniment to classical Indian singing or music. In this work, a mathematical model was developed to describe the response of this instrument and to analytically determine the areal density distribution required to obtain overtones that were rational multiples of each other. The model was verified by comparing the exact Bessel function solution of the constant density drum with the results obtained using the approximate method outlined in this paper. The maximum error obtained for the first 10 natural frequencies was less than 1% while the associated mode shapes differed by less than 5%. The bi-density model of the tabla, with a mass ratio of 4.1 and a radius ratio of 0.49, predicted natural frequency ratios of approximately 1.1:2:3 (twice):4 (twice) for the fundamental and the first few overtones. This compares well with previously reported experimental data.     

Dioxobridged complexes of molybdenum (IV) and tungsten (IV) with N-alkylphenothiazines and their interactions with L-cysteine and L-histidine

Six new dioxobridged complexes of molybdenum (IV) and tungsten (IV) with N-alkylphenothiazines having the general formula M₂O₄(L)₂(H₂O)₂ [where M = molybdenum or tungsten and L = N-alkylphenothiazines] have been synthesised. The complexes have been characterised on the basis of analytical, molar conductance, magnetic susceptibility, spectral data, TGA and DTA. The low magnetic moments for the complexes are due to spin-spin interaction or metal-metal bonding. The interactions of these complexes with some biologically important amino acids have been studied.     

A rapid method for spectrophotometric determination of molybdenum in alloy steels

Summary A Rapid Method for Spectrophotometric Determination of Molybdenum in Alloy Steels Molybdenum (VI) forms an orange-red coloured mixed-ligand complex with perazine dimalonate and thiocyanate at room temperature (27°) in hydrochloric acid. The complex is soluble in ethanol. It exhibits absorption maximum at 460 nm. Beer's law is valid over the molybdenum concentration range 0.1–14.0,g/ml. Sandell's sensitivity of the reaction is 0.9·10^–3 g Mo/cm² and the molar extinction coefficient is 1.06·10⁴ 1·mol^–1·cm^–1 at 460 nm. The stoichiometry of the complex is (Perazine·H) [MoO(SCN)₄] as shown by Job's method, equilibrium shift method and elemental analyses of the isolated complex. The proposed method has been used for the determination of molybdenum in ores, alloy steels and in synthetic mixtures containing chromium, tungsten, iron, cobalt, nickel and copper.Presented at the 36th Pittsburgh Conference and Exposition on Analytical Chemistry and Applied Spectroscopy, New Orleans, February 25-March 1, 1985.