The synthesis and characterization of a series of Sn( ii ) and Sn( iv ) complexes supported by the highly electron-withdrawing dianionic perfluoropinacolate (pin F ) ligand are reported herein. Three analogs of [Sn IV (pin F ) 3 ] 2− with NEt 3 H + ( 1 ), K + ( 2 ), and {K(18C6)} + ( 3 ) counter cations and two analogs of [Sn II (pin F ) 2 ] 2− with K + ( 4 ) and {K(15C5) 2 } + ( 5 ) counter cations were prepared and characterized by standard analytical methods, single-crystal X-ray diffraction, and 119 Sn Mössbauer and NMR spectroscopies. The six-coordinate Sn IV (pin F ) complexes display 119 Sn NMR resonances and 119 Sn Mössbauer spectra similar to SnO 2 (cassiterite). In contrast, the four-coordinate Sn II (pin F ) complexes, featuring a stereochemically-active lone pair, possess low 119 Sn NMR chemical shifts and relatively high quadrupolar splitting. Furthermore, the Sn( ii ) complexes are unreactive towards both Lewis bases (pyridine, NEt 3 ) and acids (BX 3 , Et 3 NH + ). Calculations confirm that the Sn( ii ) lone pair is localized within the 5s orbital andmore »
SN 2013aa and SN 2017cbv: Two Sibling Type Ia Supernovae in the Spiral Galaxy NGC 5643
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- https://doi.org/10.3847/1538-4357/ab8e3e
