The synthesis method of lithiated d-metal oxides using molten formate mixtures as precursors has been developed and the isothermal (800 °C) cross section of pseudo ternary Li–Mn–Co oxide system under ...ambient oxygen pressure has been investigated by XRD,
7
Li NMR, and galvanostatic electrochemical methods. Special attention has been paid to the compositions inside the quadrangle restricted by solid solutions LiCoO
2
–LiCo
0.85
Mn
0.15
O
2
with the layered structure of α-NaFeO
2
and solid solutions LiMn
2
O
4
–LiMnCoO
4
with the structure of spinel. It was found that, depending on the composition, three types of equilibrium phases could be formed: spinels LiLi,Mn,Co
2
O
4
with a part of Li atoms in octahedral sites, cation-deficit layered compounds Li
1 −
δ
Co,MnO
2
, and Li
2
MnO
3
. Areas of (co)existence of these phases were plotted on the composition plane of the pseudo-ternary Li–Mn–Co system. Electrochemical properties of the compositions inside the quadrangle LiCoO
2
–LiCo
0.85
Mn
0.15
O
2
–LiMn
2
O
4
–LiMnCoO
4
are determined by the content and average oxidation number of Mn atoms, which is higher than in the normal spinels LiMn,Co
2
O
4
. Thus, the specific capacities of the polyphase compositions are lower in comparison with the binary solid solutions LiMn,Co
2
O
4
or pure LiCoO
2
.
The title spirocyclic compound (alternative name: 2,2,4,4‐tetrachloro‐9,9‐dimethyl‐7,11‐dioxa‐1,3,5‐triaza‐2λ5,4λ5,6λ5‐triphosphaspiro5.5undeca‐1,3,5‐triene), C5H10Cl4N3O2P3, does not contain ...alternating long–short P—N bond lengths in the phosphazene ring P—N 1.559 (2)–1.596 (2) Å, as are observed in other analogous spirocyclic compounds. The six‐membered phosphazene ring has a chair conformation in the solid state, but a conformational equilibrium in solution is indicated by NMR spectroscopy.
We search for excited charmed baryons in the $\Lambda_c^+\eta$ system using a
data sample corresponding to an integrated luminosity of 980 $\rm fb^{-1}$. The
data were collected by the Belle detector ...at the KEKB $e^{+}$$e^{-}$
asymmetric-energy collider. No significant signals are found in the
$\Lambda_c^+\eta$ mass spectrum, including the known $\Lambda_c(2880)^+$ and
$\Lambda_c(2940)^+$. Clear $\Lambda_c(2880)^+$ and $\Lambda_c(2940)^+$ signals
are observed in the $pD^0$ mass spectrum. We set upper limits at 90\%
credibility level on ratios of branching fractions of $\Lambda_c(2880)^+$ and
$\Lambda_c(2940)^+$ decaying to $\Lambda_c^+\eta$ relative to
$\Sigma_c(2455)\pi$ of $<0.13$ for the $\Lambda_c(2880)^+$ and $<1.11$ for the
$\Lambda_c(2940)^+$. We measure ratios of branching fractions of
$\Lambda_c(2880)^+$ and $\Lambda_c(2940)^+$ decaying to $pD^0$ relative to
$\Sigma_c(2455)\pi$ of $0.75 \pm 0.03(\text{stat.}) \pm 0.07(\text{syst.})$ for
the $\Lambda_c(2880)^+$ and $3.59 \pm 0.21(\text{stat.}) \pm
0.56(\text{syst.})$ for the $\Lambda_c(2940)^+$.
The novel dimeric compounds Ph2Sb(O2PR2)O2·2CH2Cl2 R = cycl-C6H11 (2) and cycl-C8H15 (3) have been synthesized by reacting diphenylantimony trichloride (1) with 3 mol equiv of silver acetate followed ...by 1 mol equiv of the phosphinic acid. By the same route under more stringent conditions to exclude moisture, the mixed phosphinate−acetate Ph2Sb(O2P(C6H11)2)(O2CMe)2O (4) was isolated and characterized. Treatment of 2 with acetic acid/water affords the tetranuclear cage Ph8Sb4O4(OH)2(O2P(C6H11)2)2·CH3COOH·CH2Cl2 (5); it is possible to convert 5 to 2 by heating it with an excess of the phosphinic acid. Compounds 2, 3, and 5 have been characterized by X-ray structural analysis. All of them possess four membered Sb2O2 rings with hexacoordinated antimony. In 5 the antimony atoms in the two Sb2O2 rings are connected by oxo bridges on two sides to give an Sb4O6 cage. These structures are correlated with those of known tin cages.
Three-wavelength spectrophotometric method has been developed for the simultaneous estimation of atazanavir sulfate (ATZ) and ritonavir (RIT) in pharmaceutical preparations. The absorbance value at ...279.7nm was used for the estimation of ATZ where RIT showed zero absorbance. The absorbance value for RIT was estimated by taking difference in absorbance at two wavelengths 248 nm and 252 nm. This method obeyed Beer’s law in the concentration range of 9-45 μg/mL for ATZ, and 3-15 µg/mL for RIT. The results of analysis have been validated statistically and recovery studies confirmed the accuracy of the proposed method. The percentage recoveries were found to be 101.3±0.4 for ATZ and 99.8± 0.2 for RIT. The assay values of atazanavir and ritonavir were found to be 100.7±0.7 and 103.0±1.2, respectively. The method was found to be simple, rapid, accurate, precise and sensitive. Hence, this method can be used for routine analysis of these drugs in formulations.
We report the first evidence for the $h_{b}(\text{2P}) \to
\Upsilon(\text{1S})\eta$ transition with a significance of $3.5$ standard
deviations. The decay branching fraction is measured to be
...$\mathcal{B}h_{b}(\text{2P}) \to \Upsilon(\text{1S})\eta=(7.1 ~^{+3.7}
_{-3.2}\pm 0.8)\times10^{-3}$, which is noticeably smaller than expected. We
also set upper limits on $\pi^0$ transitions of $\mathcal{B}h_{b}(\text{2P})
\to \Upsilon(\text{1S})\pi^0 < 1.8\times10^{-3}$, and
$\mathcal{B}h_{b}(\text{1P})\to \Upsilon(\text{1S})\pi^0 < 1.8\times10^{-3}$,
at the $90\%$ confidence level. These results are obtained with a
$131.4$~fb$^{-1}$ data sample collected near the $\Upsilon(\text{5S})$
resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$
collider.
We report a study of the hadronic transitions
$\chi_{bJ}(2P)\to\omega\Upsilon(1S)$, with $\omega\to\pi^{+}\pi^{-}\pi^{0}$,
using $28.2\times10^6~\Upsilon(3S)$ mesons recorded by the Belle detector. ...We
present the first evidence for the near--threshold transition
$\chi_{b0}(2P)\to\omega\Upsilon(1S)$, the analog of the charm sector decay
$\chi_{c1}(3872)\to\omega J/\psi$, with a branching fraction of
$B\big(\chi_{b0}(2P)\to\omega\Upsilon(1S)\big) =
\big(0.55\pm0.19\pm0.07\big)\%$. We also obtain branching fractions of
$B\big(\chi_{b1}(2P)\to\omega\Upsilon(1S)\big) =
\big(2.39{}^{+0.20}_{-0.19}\pm0.24\big)\%$ and
$B\big(\chi_{b2}(2P)\to\omega\Upsilon(1S)\big) =
\big(0.47{}^{+0.13}_{-0.12}\pm0.06\big)\%$, confirming the measurement of the
$\omega$ transitions of the $J=1,2~P$--wave states. The ratio for the $J=2$ to
$J=1$ transitions is also measured and found to differ by 3.3 standard
deviations from the expected value in the QCD multipole expansion.
Cyclic hexacoordinate phosphorus compounds Swamy, K. C. Kumara; Kumaraswamy, Sudha; Said, Musa A. ...
Current science (Bangalore),
02/2000, Letnik:
78, Številka:
4
Journal Article
Recenzirano
New developments on anionic, cationic and neutral hexacoordinate phosphorus compounds in which phosphorus is a part of a ring are described. Relevance of these species to an understanding of the ...reaction mechanisms at both tetracoordinate and pentacoordinate phosphorus(V) centres is highlighted.
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