The Coordination Chemistry and Clustering of Subvalent Ga+ and In+ upon Addition of σ-Donor Ligands

This review addresses the coordination chemistry (mainly) enabled by using the univalent [M(fluoroarene)(2-3)](+)[Al(ORF)(4)](-)-salts (M=Ga, In; R-F=C(CF3)(3)) as robust starting materials. In the course of this work, it became clear that the orbital energy of the ns(2) (n=4, 5) lone pair in such [:M(L)(n)](+) cations reacts drastically depending on the quality of the ligand employed. Activation of the lone pair with strong sigma-donor ligands might be used for bond activation and oxidative addition reactions. Yet, unexpectedly, using sterically undemanding and electron rich ligands with limited pi-accepting properties, aggregation to highly charged and rather unusual univalent cluster cations [M-n(L)(m)]degrees(+) (n=2 horizontal ellipsis 5, m=4 horizontal ellipsis 6, o=3 horizontal ellipsis 5) was observed. An overview and rationalization of these findings is presented here.

Automated summary

This review discusses the coordination chemistry enabled by using univalent salts as starting materials, highlighting the significant impact of ligand quality on the reactivity of the lone pair in cations. Different ligands can either activate the lone pair for bond activation and oxidative addition reactions, or lead to the formation of highly charged cluster cations through aggregation.