Relative basicities of the oxygen atoms of the Linquist polyoxometalate [Mo6O19]2– and their recognition by hydroxyl groups in radical cation salts based on functionalized tetrathiafulvalene π donors

Abstract

Electrocrystallization of three hydroxylated donor molecules derived from tetrathiafulvalene (TTF) or ethylenedithiotetrathiafulvalene (EDT-TTF), i.e. Me₃TTF-CH₂OH, EDT-TTF(CH₂OH)₂ and TTF(CH₂OH)₄, in the presence of [n-Bu₄N⁺]₂[Mo₆O₁₉]^2– afforded 2∶1 cation radical salts, [donor⁺˙]₂[Mo₆O₁₉]^2–, whose crystal structures have been solved by X-ray diffraction. In the three different salts complex hydrogen bond networks develop in the solid state where the oxygen atoms of both the hydroxyl groups and the [Mo₆O₁₉]^2– anions act as hydrogen bond acceptors. The observed hydrogen bonding directed toward one surface, bridging oxygen atom of [Mo₆O₁₉]^2– is rationalized by an analysis of ab initio calculations of the distribution of electrostatic potentials.