Preparation,and infrared and thermal properties of six adducts of tetrakis-(8-hydroxyquinolinato)thorium(IV)

Six adducts of the tctrakis(8-hydroxyquinolinato) complex of thorium(IV) with 8-hydroxyquinoline, pyridine, urea, dimethylsulphoxide, dimethylformamide and 1,10-phenanthroline were prepared and characterized, the infrared bands for the room-temperature forms are given and their particular thermal properties are reported. The thermal analyses were performed mostly in the presence of air, but in some cases an argon atmosphere was used for comparison. The adducts were lost from the principal complex at temperatures varying between 110 and 290°. Intermediate oxygenated complexes were formed in each case at about 400°. The thermal data suggest the standardization of a procedure for the formation of Th(C₉H₆NO)₄.

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Zusammenfassung Sechs Addukte des Tetrakis(8-hydroxyquinolinato)-Komplexes von Thorium(IV) mit 8-Hydroxyquinolin, Pyridin, Harnstoff, Dimethylsulphoxid, Dimethylformamid und 1,10-Phenanthrolin wurden dargestellt und charakterisiert. Infrarotbanden und spezielle thermische Eigenschaften der Raumtemperatur-Formen sind angegeben. Die thermischen Analysen wurden meist in Luft ausgeführt, in einigen Fällen zu Vergleichszwecken aber auch in Argonatmosphäre. Die Addukte wurden vom Komplex bei Temperaturen zwischen 110 und 290 °C abgegeben. Intermediäre oxydierte Komplexe wurden in jedem Fall bei etwa 400 °C gebildet. Die thermischen Daten ermöglichen die Standardisierung eines Verfahrens zur Darstellung von Th(C₉H₆NO)₄.

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-(8- ) (IV) 8- , , , - , 1,10-. - , . , , . 110–290°. 400° . Th(C₉H₆NO)₄.

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We are grateful to the Bangladesh University Grants Commission for a Fellowship Grant to AR.     

Photoactive metallocyclodextrins: sophisticated supramolecular arrays for the construction of light activated miniature devices

The introduction of photoactive metal centres onto cyclodextrin receptors opens up new possibilities for the design of sensors, wires and energy conversion systems. This tutorial review focuses on strategies involving such metallocyclodextrins for the construction of supramolecular arrays with light-activated functions. The assembly procedures for building such arrays are presented, together with the features required for their functions both as sensors for ion or small molecule detection and as wires for photoinduced long-range energy or electron transport. Systems for metal ion sensing are described where the cyclodextrin plays a mediating role in influencing the luminescence properties of an organic probe, responsive to metal binding. Small molecule sensing by the cyclodextrin cavity is realised using luminescent lanthanide or transition metal functionalised cyclodextrins. The light signal of the photoactive metal is switched on or off upon binding an analyte in the cyclodextrin cavity. The metallocyclodextrin systems that function as wires are distinguished by the controlled assembly of transition metal polypyridine and metalloporphyrin units. These units have inherent photoactivity that defines the vectorial direction of energy or electron transfer processes through the wire.     

Photosensitized Oxygenation of Abieta-7,9(11)-dien-13β-ol

Dehydration of abiet-8-ene-7β, 13β-diol (ibozol, 1 ) leads to abieta-7,9(11)-dien-13β-ol ( 2 ) which aromatizes slowly to the known abieta-8,11,13-triene ( 3 ). Photosensitized oxygenation of the heteroannular diene 2 yields a mixture from which three compounds were identified; abiet-7-ene-9α, 11α, 13β-triol ( 4 ), abieta-8,11,13-trien-7-one ( 5 ), and abieta-8,11,13-trien-7α-ol ( 6 ).     

A database for QA/QC in neutron activation analysis and gamma-ray spectrometry

A database has been designed for storing, retrieving and analyzing information about samples, experimental conditions and results obtained by neutron activation analysis and gamma-ray spectrometry. It has been created using Microsoft ACCESS 2002 under a Windows operating system. The database has been designed not only for saving information but also for quality assurance and quality control purposes. The structure of the relational design has been discussed and demonstrated with a new graphical feature of ACCESS 2002 called PIVOTCHART.     

EPR SPECTROSCOPY OF ETHIDIUM NITRENE AND PROFLAVINE NITRENE COORDINATED TO SELF-COMPLEMENTARY DINUCLEOTIDE MINI-DUPLEXES

Abstract— Photolysis of ethidium azide ( lb ) and proflavine azide ( 2b ) immobilized in glassy media at 77 K produces triplet EPR spectra of the corresponding triplet nitrenes lc and 2c . The resonance field positions of the nitrenes are shifted by the presence of self-complementary dinucleotides. Control experiments indicated that the interaction of lc and 2c with C_PG mini-duplexes is consistent with intercalation.     

Retention of alkali,alkaline earth and transition metals on an itaconic acid cation-exchange column. Eluent pH,ionic strength and temperature effects upon selectivity

The unusual selectivity of a methylene succinic (itaconic) acid modified polymeric column was investigated for the separation of alkali, alkaline earth, transition and heavy metals employing non-chelating inorganic eluents. The retention of selected metal ions on the column was investigated with simple HNO3 eluents and eluents prepared from KNO3 and KCl salts of varying pH (adjusted using HNO3). From these studies both the effect of eluent ionic strength and pH upon retention was evaluated for the itaconic acid stationary phase. The results obtained showed that despite slow exchange kinetics causing poor efficiencies, acceptable baseline separations of selected alkaline earth and transitions could be obtained under optimum conditions (the baseline separation of Mg(II), Ca(II), Mn(II), Cd(II), Zn(II) and Co(II) was possible using a 15 mM KNO3-5 mM KCl eluent at pH 3.50 in under 25 min). The use of an simple ionic strength step gradient was shown that facilitated the addition of Pb(II) to the above group of metal ions. An investigation into the effect of temperature upon peak efficiency and retention showed increased column temperature could be used to improve the resolution of closely eluting metal ions such as Ca(II) and Sr(II) and Ca(II) and Mn(II).     

A sequential injection spectrophotometric method for the determination of penicillamine in pharmaceutical products by complexation with iron(III) in acidic media

A simple, robust and sensitive sequential injection spectrophotometric method for the assay of penicillamine (PA) in pharmaceutical formulations is developed. The method was based on the complex formation when PA is reacted with iron(III) solution in hydrochloric acid media. The deep blue colored PA-iron(III) complex produced is monitored at a maximum wavelength of 600 nm. A five level orthogonal array design coupled to genetic algorithm was employed to obtain the optimum experimental conditions for the determination of PA using peak absorbance as the measure of the system's performance criterion. A linear dynamic range for the determination of PA of 25-300 ppm was obtained with a sampling frequency of 50 h⁻¹ and a relative standard deviation of less than 0.98%. The method was successfully applied to the determination of PA in pharmaceutical formulations.     

Pyridazines. LIX. Synthesis of c-annelated pyridazines from 3-amino-4-pyridazinecarbonitrile

The utility of the aminonitrile 1 as an educt for the preparation of several new examples of heterocyclefused pyridazines (the [1,2,4]triazolo[1′,5′:1,6]pyrimido[4,5-c]pyridazine 7 , the pyrimido[4,5-c]pyridazines 8, 10a,b , and the pyrido[2,3-c]pyridazine 11 ) is demonstrated.     

Synergistic extraction of Ce(III), Eu(III) and Tm(III) with a mixture of picrolonic acid and benzo-15-crown-5 in chloroform

Summary The synergistic mixture comprising picrolonic acid (HPA) and benzo-15-crown-5 (B15C5) in chloroform has been used for the extraction of Ce(III), Eu(III) and Tm(III) as representatives of lanthanide(III) ions from pH 1-2 solutions having ionic strength of 0.1 mol^. dm^-3(K⁺/H⁺, Cl^-). The composition of the extracted species has been determined as M(PA)₃^. nB15C5 where M is Ce, Eu and Tm and n=1 or 2. The influence of various anions and cations on the extraction of these ions has also been studied and only oxalate, cyanide and tartrate have some deleterious effect. The extraction equilibrium constants have been evaluated and discussed.