Isolated cationic crown ether complexes of gallium(i) and indium(i)

Abstract

The recently reported homologous low-valent indium and gallium salts M⁺[Al(OR^F)₄]⁻ (M = Ga, In; R^F = C(CF₃)₃) were used to extend the coordination chemistry of Ga^I and In^I to the isolated [18]crown-6 complexes [M([18]crown-6)(PhF)₂]⁺[Al(OR^F)₄]⁻ in fluorobenzene solution (PhF = C₆H₅F). In contrast to known ion-paired compounds for M = In, our complexes are undisturbed and in the solid state free of contacts to the anion. A peculiar combination of very weak η¹- and η⁶-coordination to the PhF-solvent was observed that allows speculation about the presence of a stereochemically active lone pair at M^I. Structure and energetics of these novel salts were rationalized on the basis of DFT calculations.