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

The recently reported homologous low-valent indium and gallium salts M+[Al(ORF)(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(ORF)(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 eta(1)- and eta(6)-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.