Synthesis and redox properties of triarylmethane dye cation salts of anions [M6O19]2- (M = Mo, W)

Abstract

Four salts have been isolated combining the triarylmethane dye cations pararosaniline (PR+) and crystal violet (CV+) with the hexametalates [M6O19]2- (M = Mo, W). A new hexatungstic acid H2[W6O19]·4dma (dma = dimethylacetamide) was isolated and is a useful synthon for hexatungstate salts. Single-crystal X-ray diffraction confirmed the presence of PR+ and [Mo6O19]2- ions in [PR]2[Mo 6O19]·6dmf (dmf = dimethylformamide). A number of charge-assisted hydrogen bonds N-H⋯O exist between the cation -NH 2 functions and the anion oxygen atoms. Comparative cyclic voltammetry of salts [A]Cl (A = PR, CV), [Bu4N]2[M 6O19]2- and A2[M6O 19] was established in MeCN and Me2SO solutions and of solids in conta..