A phenoxo–azido assorted Schiff base copper(II) bridged dimer in trace level fluorescence sensing of a pesticide: a DFT supported phenomenon

A binuclear phenoxo- and azido-bridged copper(II) Schiff base complex has been synthesized along with its mononuclear copper-Schiff base analog. The compounds have been characterized by IR spectroscopy and CHN elemental analysis. The single-crystal structure and variable temperature magnetic properties of the binuclear compound have been studied from the X-ray crystallographic data and superconducting quantum interference device magnetometry, respectively. The synthesized crystalline binuclear complex has interesting spectral features that allow it to act as a spectral sensor toward an organophosphorus pesticide which is a potential environmental toxicant coming to the environment as agricultural waste. Although both the mononuclear and binuclear complexes are suitable as sensors for the organophosphorus, the binuclear complex being crystalline is suitable for attaining structural and mechanistic details of the interaction. Density functional theory calculations and ESI MS analysis of the interactions with the binuclear complex suggest that the binding of organophosphorus substrate with 2 occurs through one copper center.     

Meson properties from a bag model compared to lattice theory and heavy ion experiments

A bag at temperature (T) with pressureB(T)=B(0)[1?(T/T _c )⁴] is shown to be consistent with recent lattice data on the π and the ρ mesons. The limiting temperature,T _l , of the pion bag from the Bekenstein entropy bound is lower than that of other mesons. This agrees with the thermal distribution of π,K and the ρ in heavy ion collisions, which (unlike proton-nucleus or pp data) show a marked difference inT of pion and other mesons in the mid-rapidity region.     

Preparation of a Ru/Al2O3 catalyst from Ru3(CO)12 infrared and XPS study

A supported ruthenium catalyst on alumina prepared from Ru₃(CO)₁₂ has been studied by infrared and X-ray photoelectron spectroscopy (XPS). The triatomic cluster is retained on the support but breaks down at 150°C. Complete elimination of the carbonyl groups requires heating at 350°C under vacuum. XPS studies show that the decomposed catalyst does not change on further reduction in H₂ at 400°C. The ruthenium atoms remain trapped within the pores of the support.

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Al₂O₃, Ru₃(CO)₁₂, (XPS). , 150°C . 350°C . XPS , H₂ 400°C . .

     

Strong-metal-support-interaction in titania-supported rhodium, ruthenium, and rhodium-ruthenium bimetallic catalysts

Titania-supported rhodium, ruthenium and rhodium-ruthenium catalysts were prepared by impregnation followed by reduction at 573 K (low temperature reduced-LTR) and 773 K (high temperature reduced — HTR). Temperature programmed desorption of hydrogen showed the existence of strong-metal-support-interaction (SMSI) in rhodium and ruthenium catalysts, but not in the bimetallic catalyst. In either case, metal-hydrogen bond strength had undergone change in going from an LTR to HTR sample. X-ray photoelectron spectroscopy (XPS) results did not show any electron transfer between metal and support in any of the catalysts but electron transfer from rhodium to ruthenium was indicated in the bimetallic catalyst under HTR.     

Triple-quantum magic angle spinning (27)Al NMR of aluminum hydroxides

We show that (27)Al triple-quantum magic angle spinning (3Q-MAS) experiments alleviate the second-order quadrupolar broadening to reveal the structure-building units of nonequivalent aluminum octahedra in the most extensively studied aluminum hydroxides, namely, gibbsite, bayerite, and boehmite. Further, aided by ab initio calculations of the electric field gradient tensors, the 3Q-MAS/MAS results are shown to lead to the assignment of (27)Al isotropic resonances to the aluminum positions in their X-ray-determined structures. The present work paves the way for future studies on various structurally transformed materials derived from these basic aluminum hydroxides.