Adsorption, desorption, and surface-promoted hydrolysis of glucose-1-phosphate in aqueous goethite (α-FeOOH) suspensions

Adsorption, desorption, and precipitation reactions at environmental interfaces govern the fate of phosphorus in terrestrial and aquatic environments. Typically, a substantial part of the total pool of phosphorus consists of organophosphate, and in this study we have focused on the interactions between glucose-1-phosphate (G1P) and goethite (α-FeOOH) particles. The adsorption and surface-promoted hydrolysis reactions have been studied at room temperature as a function of pH, time, and total concentration of G1P by means of quantitative batch experiments in combination with infrared spectroscopy. A novel simultaneous infrared and potentiometric titration (SIPT) technique has also been used to study the rates and mechanisms of desorption of the surface complexes. The results have shown that G1P adsorption occurs over a wide pH interval and at pH values above the isoelectric point of goethite (IEP(goethite) = 9.4), indicating a comparatively strong interaction with the particle surfaces. As evidenced by IR spectroscopy, G1P formed pH-dependent surface complexes on goethite, and investigations of both adsorption and desorption processes were consistent with a model including three types of surface complexes. These complexes interact monodentately with surface Fe but differ in hydrogen bonding interactions via the auxiliary oxygens of the phosphate group. The apparent desorption rates were shown to be influenced by reaction pathways that include interconversion of surface species, which highlights the difficulty in determining the intrinsic desorption rates of individual surface complexes. Desorption results have also indicated that the molecular structures of surface complexes and the surface charge are two important determinants of G1P desorption rates. Finally, this study has shown that surface-promoted hydrolysis of G1P by goethite is base-catalyzed but that the extent of hydrolysis was small.     

Capture and release of a conditional state of a cavity QED system by quantum feedback

Detection of a single photon escaping an optical cavity QED system prepares a nonclassical state of the electromagnetic field. The evolution of the state can be modified by changing the drive of the cavity. For the appropriate feedback, the conditional state can be captured (stabilized) and then released. This is observed by a conditional intensity measurement that shows suppression of vacuum Rabi oscillations for the length of the feedback pulse and their subsequent return.     

Collector Probe Measurements of Impurity Fluxes Injected into the Plasma of the T-10 Tokamak

It is shown that the efflux of impurities injected into the core plasma can be detected by collector probes in the scrape-off plasma. The time evolution, orientation and radial dependences of these effluxes allow to conclude on the impurity confinement in the core plasma and the scrape-off plasma. Moreover, recycling effects can also be measured.     

Komplexkatalyse: XXV. 31P-NMR-spektroskopische charakterisierung der anti- und syn-struktur von C3-substituierten η3-allylbis(triarylphosphit)-nickel(II)-hexafluorophosphat-komplexen und der mechanismus der durch [C3H5Ni(P(OPh)3)2]PF6 katalysierten 1,4-trans-polymerisation des butadiens

The reaction of the η₃-allylbis(triarylphosphite)nickel(II) complexes with butadiene under chain propagation to give the polybutadienyl complex, [3-RC₃H₄Ni(P(OAr)₃)₂]PF₆, was monitored by ³¹P NMR spectroscopy. In the case of the triphenylphosphite complex both the anti- and the syn-configuration could be identified by means of their different AB spectra. The anti-syn isomerization, the higher reactivity of the thermodynamically more stable syn-form, and the formation of the anti-structure as a result of each individual butadiene insertion step was also proved. From these observations an experimentally well-grounded mechanism of the trans regulation with the anti-syn isomerization as the rate-determining step could be derived for the first time.     

Shanzhisin methyl ester gentiobioside,a new iridoid - isolation and synthesis

The title compound 1 has been isolated from $\text{Canthium subcordatum}$ and its structure deduced; 1 was synthesised from shanzhiside methyl ester.     

Reactions of free radicals with monoethyldichlorochromium(III) tris(tetrahydrofuranate)

σ-Ethyl-chromium(III)dichloride · 3 THF reacts with free radicals by formation of a transient paramagnetic complex which decomposes giving the combination product of alkyl ligand and radical.