Structure Transformation of Methylammonium Polyoxomolybdates via In-Solution Acidification and Solid-State Heating from Methylammonium Monomolybdate and Application as Negative Staining Reagents for Coronavirus Observation.

We prepared polyoxomolybdates with methylammonium countercations from methylammonium monomolybdate, (CHNH)[MoO], through two dehydrative condensation methods, acidifying in the aqueous solution and solid-state heating. Discrete (CHNH)[MoO(OH)(HO)], polymeric ((CHNH)[MoO(HO)]), and polymeric ((CHNH)[γ-MoO]) were selectively isolated via pH control of the aqueous (CHNH)[MoO] solution. The HSO-acidified solution of pH < 1 produced "sulfonated α-MoO", polymeric ((CHNH)[(MoO)(SO)]).

Molar-Ratio-Dependent Coordination Assembly of Organoiridium(III)-Octatungstate Complexes in Aqueous Solution.

We scrutinized the speciation of Cp*Ir-containing tungsten oxide clusters (Cp* is pentamethylcyclopentadienyl anion) in aqueous mixtures of [(Cp*IrCl)(μ-Cl)] and NaWO in varying molar ratios. H nuclear magnetic resonance (NMR) spectroscopy revealed the formation of three distinct Cp*Ir-polyoxotungstate species in the reaction solution, and they were isolated as Na[(Cp*Ir)(μ-OH)][(Cp*Ir)HWO] (), [(Cp*Ir)(μ-OH)][(Cp*Ir){Cp*Ir(OH)}HWO] (), and [(Cp*Ir){Cp*Ir(OH)}{Cp*Ir(OH)}HWO](NO) () from the mixtures in which iridium concentration is less than, equal to, and more than the tungsten concentration, respectively. These results show the octatungstate [HWO] anion is the major polyoxotungstate species in the presence of {Cp*Ir} cations, and it has high nucleophilicity enough to bind up to six {Cp*Ir} cations on its surfaces producing a Cp*Ir-octatungstate complex.

Thermal Structure Transformation of Methylammonium Vanadate and it's Application as a Negative Staining Reagent for Observing SARS-CoV-2.

The solid-state thermal structure transformation of methylammonium vanadate, (CHNH)VO, from -150 °C to 350 °C is reported. Variable-temperature X-ray single-crystal structure analysis at 23, 0, -50, -100, and -150 °C reveal (CHNH)VO comprises of methylammonium cations and "snake-like" ([VO]) anion chains propagating along the -direction in the 2 space group. In between -150 and -100 °C, we observe a reversible structural transformation due to the re-orientation of the methylammonium cations in the crystal packing, which is also confirmed by the reversible profiles observed in differential scanning calorimetry.