MICROWAVE SPECTRA AND MOLECULAR STRUCTURE OF ACETYLENEMETHYLDIOXORHENIUM, A RHENIUM METALACYCLOPROPENEaMETALACYCLOPROPENE^{a}

$^{a}$Supported by THE NATIONAL SCIENCE FOUNDATION.Author Institution: Department of Chemistry, University of Arizona; Jet Propulsion Laboratory, California Institute of Technology; Jet Propulsion Laboratory, Anorganisch-Chemisches Institut der Technischen Universit\""{a}t M\""{u}nchenThe molecular structure for ($\eta^{2}$-acetylene) methyldioxorhenium (ACMDO) was obtained by measuring and analysing the rotational spectra for 14 isotopomers. This appears to be the first gas-phase measurement for a rhenium metalacyclopropene, and the first structural data on this compound. This complex is closely related to reaction intermediates in methyltrioxorhenium (MTO) and $O_{s} O_{4}$ catalysed oxidation reactions. These reactions are very important in industrial chemical production and for syntheses of chiral products. Only a few alkyne complexes or transitions metals in high oxidation states are known and even fewer have been structurally characterized. The microwave spectra were measured in the 4-11 GHz range using a Flygare-Balle-type pulsed-beam microwave spectrometer. Rotational constants and rhenium quadrupole coupling tensors were obtained for all isotopomers. The acetylene ligand structure is modified and exhibis partial $sp^{2}$ hybridization. The C-C bond length is increased by 0.08{\AA} to 1.29{\AA}. The H-C-C interbond angles are reduced from $180^{\circ}$ to $141^{\circ}$, and $152^{\circ}$. The quadrupole splitting patterns and systematic changes in the quadrupole coupling tensors were very helpful in making positive assignments

Nebulized spray pyrolysis of Al-doped Li7La3Zr2O12 solid electrolyte for battery applications

Nebulized spray pyrolysis followed by consolidation and sintering was used for the first time to prepare Al-doped garnet-based Li7−3xLa3Zr2AlxO12 (x = 0–0.25) (LLZO) ultra-fine grained ceramics. The structural changes from the tetragonal (x = 0), via a mixture of the cubic and the tetragonal (x = 0.07, 0.10) to the cubic modification (x = 0.15–0.25) were observed. 27Al NMR study showed that aluminum occupy the tetrahedral 24d lithium sites. Despite their low relative density (47–56%), preliminary ionic conductivities of the LLZO ceramics, were found to be 1.2 · 10− 6 S cm− 1 and 4.4 · 10− 6 S cm− 1 for tetragonal and cubic LLZO at room temperature, with activation energies of 0.55 eV and 0.49 eV, respectively