f-Block Phospholyl and Arsolyl Chemistry.

The f-block chemistry of phospholyl and arsolyl ligands, heavier p-block analogues of substituted cyclopentadienyls (Cp , C R ) where one or more CR groups are replaced by P or As atoms, is less developed than for lighter isoelectronic C R rings. Heterocyclopentadienyl complexes can exhibit properties that complement and contrast with Cp chemistry. Given that there has been renewed interest in phospholyl and arsolyl f-block chemistry in the last two decades, coinciding with a renaissance in f-block solution chemistry, a review of this field is timely. Here, the syntheses of all structurally characterised examples of lanthanide and actinide phospholyl and arsolyl complexes to date are covered, including benzannulated derivatives, and together with group 3 complexes for completeness. The physicochemical properties of these complexes are reviewed, with the intention of motivating further research in this field.