The Spectrophotometric Determination of Gallium (III) with Glycine Thymol Blue

The reaction between gallium (III) and glycine thymol blue has been studied spectrophoptometrically in order to establish the optimum conditions for determining traces of gallium. The gallium (III) glycine thymol blue complex has an absorption maximum at 560 nm against a reagent blank and is stable between pH 4.0 and 5.5. The complex has a composition 1 : 2 and a formation constant of 6.4×10⁷ under the conditions studied. Beer's law is obeyed upto 126 μg of gallium. The net molar absorptivity has been found to be 11,000. The present method is very sensitive and rapid. Anions such as citrate and tartrate inhibit the colour development of the complex.     

Studies on antimony oxides: Part I

Thermogravimetry (TG), differential thermal analysis (DTA) and X-ray diffraction studies of antimony(III) oxide, (Sb₂O₃), in air, nitrogen and argon atmospheres have been made. In air Sb₂O₃ becomes oxidized to Sb₂O₄ above 510°. The oxidation reaction proceeds in two stages as revealed by the TG and DTA curves. The behaviour of Sb₂O₃ is similar in both N₂ and Ar. Sb₂O₃ remains unaffected up to 430°, above which there is a slow, and continuous mass loss up to 550°. Above 550° Sb₂O₃ volatilizes resulting in an enormous weight loss. X-ray studies of the sublimate and the residue indicate the former to be the cubic form of Sb₂O₃ (Senarmontite) while the residue is the orthorhombic (Valentinite) structure. From the DTA curves in air, N₂ and Ar, the transition temperature for the cubic to the orthorhombic modification has been estimated to be around 610°.     

Determination of the position of the acyl groups and the nature of some amino alcohols in native ester alkaloids of the genusVeratrum

Conclusions 1. On the basis of literature data on the structure of theVeratrum alkaloids, a definite law for the arrangement of the acyl radicals in these ester alkaloids and an interrelationship between the melting point and the structure of the substituent in the C₇ position, and between the melting point and the types of amino alcohols upon which the ester alkaloids are based, has been found.2. The features mentioned may be used in studying the structure of theVeratrum ester alkaloids according to a scheme which we propose.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 440–443, 1970     

Spectroscopy of size-selected neutral silicon clusters: Remarkably similar spectra for clusters containing between ∼15 and 70 atoms

Absorption spectra have been recorded for gas phase, size-selected neutral silicon clusters using resonant one- and two-color photodissociation spectroscopy. We now have spectra between 0.94 – 5.58 eV for clusters containing up to 70 atoms. Starting at ～15 atoms, the spectra are all amazingly identical. Comparisons of the silicon cluster spectra to those of various forms of bulk silicon show that the cluster spectra have much in common with the spectrum of the most stable diamond structure of bulk crystalline silicon.     

Metal derivatives of azoles,part VII. Pyrazolato-bridged dinuclear complexes containing either cyclopalladated or -platinated trimesitylphosphine or -arsine

Summary The halogen bridges of the dimeric, cyclometallated trimesityl-arsine and -phosphine complexes of palladium(II) and platinum(II), where M=Pd or Pt and E=P or As have been replaced with pyrazolate groups to give the corresponding and less symmetric pyrazolato-bridged complexes, where M=Pd or Pt, E=P or As, Pz=pyrazolato anion, and M=Pd, E=As, Pz=3,5-dimethylpyrazolato anion. In the case of the palladium complexes,¹H. n.m.r. clearly indicates the presence of only one isomer which is most likely to have thetrans configuration while the platinum complexes are mixtures of bothcis andtrans forms.Part VI, ref. 3c     

Chloryl nitrate: a novel product of the OClO + NO3 + M recombination

The products of the reaction of OClO with NO3 were investigated between 220 and 298 K using a flow reactor and infrared, visible, and ultraviolet analysis. At temperatures below 250 K new infrared and ultraviolet absorption features were observed and assigned to the novel compound chloryl nitrate (O2ClONO2). Additionally, ClO and NO2 were observed as reaction products, indicating the existence of a second reaction channel. O2ClONO2 formation predominates at temperatures below 230 K. The reaction rate constant at 220 K is estimated to be on the order of 10(-14) cm3 molecule-1 s-1 in 1-5 Torr of helium. These observations suggest that O2ClONO2 may exist in the terrestrial stratosphere.     

Differential thermal analysis for estimation of the thermal stability of NPK fertilizers

The thermal decomposition of NPK fertilizers was studied by thermal analysis under dynamic and quasi-isothermal-quasi-isobaric conditions in open and labyrinth crucibles.It was found that under quasi-equilibrium conditions, the thermal analysis reveals mainly decomposition processes. The thermal stability of NPK fertilizers is characterized by the temperature of beginning of the spontaneous exothermic decomposition, at 180–190.

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Zusammenfassung Mittels Thermoanalyse unter dynamischen und quasi-isothermen-quasi-isobaren Bedingungen in offenen und Labyrinthtiegeln wurde die thermische Zersetzung von NPK-Düngern untersucht.Man fand, da\ die wichtigsten Zersetzungsprozesse durch die Thermoanalyse unter quasi-Gleichgewichtsbedingungen charakterisiert werden. Die thermische StabilitÄt von NPK-Düngern wird durch die Temperatur gekennzeichnet, bei der eine spontane exotherme Zersetzung einsetzt (180–190C).

     

Angular momentum decoupling approximations in the quantum dynamics of reactive systems

Two methods for implementing angular momentum decoupling approximations in quantum mechanical reactive scattering examined. Applications of both reactive and nonreactive H + H₂ collisions indicate that for the most intense individual reactive transitions and for all degeneracy-averaged ones, these decoupling methods (especially the “proper” decoupling method) yield results in good agreement with those of fully-coupled calculations. However, for the less intense reactive transitions and all individual nonreactive transitions, very large errors can result from use of these approximate methods.     

Extra-atomic relaxation energies for the 3d-transition metal series obtained with SCF hole-state calculations

A method to calculate extra-atomic relaxation energies is presented. It is based on the use of SCF hole-state calculations. The E_R^ea (2s) and E_R^ea (2p) values obtained for the 3d-transition metal series are in fair agreement with experimental values.     

Partial purification of active delta and epsilon subunits of the membrane ATPase from escherichia coli.

We have partially purified active delta and epsilon subunits of the E. coli membrane-bound Mg2+-ATPase (ECF1). Treating purified ECF1 with 50% pyridine precipitates the major subunits (alpha, beta, and gamma) of the enzyme, but the two minor subunits (delta and epsilon), which are present in relatively small amounts, remain in solution. The delta and epsilon subunits were then resolved from one another by anion exchange chromatography. The partially purified epsilon strongly inhibits the hydrolytic activity of ECF1. The epsilon fraction inhibits both the highly purified five-subunit ATPase and the enzyme deficient in the delta subunit. The latter result indicates that the delta subunit is not required for inhibition by epsilon. By contrast, two-subunit enzyme, consisting chiefly of the alpha and beta subunits, was insensitive to the ATPase inhibitor, suggesting that the gamma subunit may be required for inhibition by epsilon. The partially purified delta subunit restored the capacity of ATPase deficient in delta to recombine with ATPase-depleted membranes and to reconstitute ATP-dependent transhydrogenase. Previously we reported (Biochem, Biophys. Res. Commun. 62:764 [1975]) that a fraction containing both the delta and epsilon subunits of ECF1 restored the capacity of ATPase missing delta to recombine with depleted membranes and to function as a coupling factor in oxidative phosphorylation and for the energized transhydrogenase. These reconstitution experiments using isolated subunits provide rather substantial evidence that the delta subunit is essential for attaching the ATPase to the membrane and that the epsilon subunit has a regulatory function as an inhibitor of the ATPase activity of ECF1.