Actinide–transition metal (An–TM) bonding is an area of fundamental interest and open exploration, as the potential of f–d bonds for new reactivities and electronic structures has been explored far less exhaustively than their TM–TM counterparts. Recently, we reported a versatile strategy utilizing the potassium salt of a high-valent iridium polyhydride, K[IrCp*H₃], for the formation of hydride-bridged actinide–iridium multimetallics U{(μ-H)₃IrCp*}₄ (1), Th{[(μ-H₂)(H)IrCp*]₂[(μ-H)₃IrCp*]₂} (2), and octanuclear complex {U[(μ²-H₃)IrCp*]₂[(μ³-H₂)IrCp*]}₂ (3). Computational studies with natural bonding orbital analysis on these complexes indicate significant bonding character between U/Th and Ir in 1 and 2, with density functional theory calculations suggesting f/d-orbital overlap in the singly-occupied molecular orbitals of the uranium/iridium species 1. Following this initial report on An-Ir multimetallics, subsequent work with the potassium salts K[ReCp*H₅] and K[OsCp*H₄] has afforded novel U–Re bonded species as well as the first examples of U–Os interactions. Computational studies on the An–TM interactions will be discussed, with a focus on the ramifications of TM identity on An–TM bonding. Finally, early results in the ability of U^III–Ir bimetallic species to cleave strong bonds in small molecules will be presented.

Michael Boreen

Appearances