Interaction of Polymethine Dyes with Detonation Nanodiamonds

Among cationic, anionic, and merocyanine polymethine dyes, the binding to detonation nanodiamond (DND) colloid particles in hydrosol occurs only for negatively charged dye species. This, in view of the positive ζ-potential of the DND used in this study, suggests the predominance of electrostatic interactions over other intermolecular forces in such systems. Indeed, after decorating the merocyanine and the cationic dye by one and two negatively charged sulfopropyl groups, respectively, so that the net charge of their colored species becomes negative, the compounds also demonstrate affinity to the DND particles. In all cases, the binding of dyes to DND is accompanied by a decrease in fluorescence intensity and a bathochromic shift of their absorption and fluorescence bands. A quantitative study of the dyes adsorption on the DND nanoparticles as performed using the Küster-Freundlich and Langmuir equations reveals some peculiarities of their attaching to the DND aggregates and allows estimating the specific area of the DND particles at a concentration of 0.0212 wt/vol %.     

Electrochemical characteristics of transition-metal trichalcogenides in the secondary lithium battery

Transition-metal trichalcogenides have been investigated as cathode materials in the lithium electrochemical cell. Three lithium ions per TiS₃ molecule have been found to be marginally reversible, while only one lithium is reversible in TaSe₃. This difference may be related to exfoliation of these substances due to the progress of lithium intercalation.     

Surface tension of polymer solutions

Summary Heats of dilution and surface tensions of a polystyrene-cyclohexane solution have been measured in a wide temperature range covering the theta-temperature. Surface tensions as well as interaction parameters obtained from heats of dilution show no discontinuity at0. Concentration of polymer adsorbed on the surface has been calculated, it decreases with increasing temperature. Plots of interaction parameter vs.1/T give two straight lines which cut at the theta-temperature.

---

Zusammenfassung Verdünnungswarmen and Oberflächenspannungen einer Polystyrol-Cyclohexan-Lösung wurden in einem großen Temperaturbereich gemessen, der die Thetatemperatur einschließt. Aus den Verdünnungswärmen wurden die Wechselwirkungsparameter berechnet. Sowohl Oberflächenspannung als such Wechselwirkung zeigen gegen die Temperatur aufgetragen keine Diskontinuität an der Thetatemperatur. Die Konzentration des an der Oberfläche adsorbierten Polymeren wurde berechnet, sic nimmt mit steigender Temperatur ab. Auftragungen des Wechselwirkungsparameters gegen die reziproke Temperatur ergeben zwei Gerade, die sich bei der Thetatemperatur schneiden.

---

---

With 5 figures     

The structures of new isotetracenone antibiotics,kerriamycins a,b and c

Based on ¹H and ¹³C NMR spectral analysis, the structures of kerriamycins A, B and C, new isotetracenone antibiotics, have been elucidated as shown in Fig. 1. Kerriamycin A contains a novel sugar, kerriose.     

The chloroform extraction of nickel with oxine from perchlorate and sulfate solutions

Nickel-oxine complexes extracted from perchlorate and sulfate solutions with chloroform were isolated and their compositions were determined. They were Ni₂(Ox)₃(HOx)₃ClO₄ from perchlorate solution at low pH and Ni₂(Ox)₄(HOx)₂ from perchlorate solution at high pH or from sulfate solution. The extraction equilibria, 2Ni²⁺+6HOx(o)+ClO^-₄?Ni₂(Ox)₃(HOx)₃ClO₄(o)+3H⁺, 2Ni²⁺+ 6HOx(o)?Ni₂(Ox)₄(HOx)₂(o)+4H⁺ and Ni₂(Ox)₃(HOx)₃ClO₄(o)?Ni₂(Ox)₄ (HOx)₂(o)+H⁺+ClO^-₄, were proposed and the equilibrium constants were determined to be 10^7.58,10^-0.82 and 10^-8.75, respectively, at ionic strength 0.1 and 20°.     

Strain,orbital interaction,and conformation of propella[34]prismane and its precursor diolefin

Factors that influence the intramolecular [2+2] photochemical ring closure reaction of multiply bridgedsyn-tricyclo[4.2.0.0^2.5]octa-3,7-diene (2) leading to propella[3₄]prismane (1) are analyzed. The unfavorable, large increase in strain (89 kcal mol^–1) calculated for this reaction is overcome by the favorable ordering of frontier molecular orbitals, which is caused primarily by bridging of the juxtaposed double bonds with trimethylene chains in2. This conclusion is based on detailed analysis of the frontier molecular orbitals (FMO) of cycloocta-1,5-diene (6), cyclodeca-1,6-diene (7), and tricyclo-[4.2.0.0^2.5]octa-3, 7-diene (3), bridged with alkylene groups of various lengths, in terms of Paddon-Row's theory of through-bond interaction by the use of AM1 semiempirical MO method. In addition to the -orbital interaction through an even number of C-C bonds, the double-bond-double-bond distance is recognized to be an important factor for the ordering of FMOs. It is suggested that reduction of this distance in6 by only a few tenths of an Ångstrom will change the FMO ordering and allow the intramolecular [2+2] cycloaddition to proceed. Potential energy calculations by MM2 indicate that the trimethylene bridges in1 and2 are so flexible that they appear flat on the NMR time scale.     

238U Mössbauer Study on the 5f-Quadrupoles in Uranium-Based Intermetallics

We have determined the distribution of the 5f-quadrupoles and detected the 5f-quadrupole order in the uranium intermetallics, uranium dipnictides and UPd₃, with ²³⁸U Mössbauer spectroscopy. We have declared that the distribution of the 5f-qaudrupoles depends on the magnetic sequence in uranium dipnictides. The distribution of the 5f-quadrupole is spherical in UBi₂, while those are oblate within c-plane in UP₂, UAs₂ and USb₂. We have observed the sudden drop of the recoil-free fraction above the transition temperature of the quadrupole order in UPd₃. The present result suggests the change of the phonon states due to the quadrupole order in this compound.

     

238U Mössbauer study on the magnetic properties of uranium-based heavy fermion superconductors

We have performed ²³⁸U Mössbauer spectroscopy of uranium-based heavy fermion superconductors, UPd₂Al₃ and URu₂Si₂, in order to investigate their physical properties, mainly their magnetic properties. The slow relaxation of magnetic hyperfine interaction in a paramagnetic state and the static hyperfine field has been observed in an antiferromagnetic ordered state for each compound. The line-widths have maximum at their characteristic temperatures where their magnetic susceptibilities have maximum values.