Emerging chemistry of organoarsenic-ligated functional metal complexes

Organoarsenic ligands have long been far less extensively explored than their phosphorus analogs, mainly because of safety concerns associated with volatile and toxic arsenic precursors. However, recent progress in practical synthetic methods has enabled access to a wide variety of arsine, arsine oxide, and multidentate organoarsenic ligands, opening new opportunities in coordination chemistry and functional materials. In this review, we summarize recent advances in metal complexes bearing organoarsenic ligands, with a particular emphasis on their structures and photophysical properties. We first outline synthetic strategies for organoarsenic ligands, including conventional and recently developed safer routes. The resulting ligand library covers monodentate, bidentate, mixed-donor, and multidentate systems. We then discuss luminescent metal complexes based on Cu(I), Au(I), Pt(II), Re(I), Os(II), and Eu(III), highlighting how arsenic affects coordination geometry, spin–orbit coupling, metallophilic interactions, charge-transfer excited states, and non-radiative deactivation pathways. Finally, we describe advanced functional materials, including porous materials, stimuli-responsive luminophores, vapor-triggered structural transitions, and processable/recyclable luminescent coordination polymers. These examples demonstrate that organoarsenic ligands are not merely heavier analogs of phosphines but rather provide unique design elements for controlling structure, dynamics, and excited-state behavior in functional metal complexes.