Organometallic Neptunium Chemistry

Identification of the Formal +2 Oxidation State of Neptunium: Synthesis and Structural Characterization of {NpII[C5H3(SiMe3)2]3}1

We report a new formal oxidation state for neptunium in a crystallographically characterizable molecular complex, namely Np²⁺ in [K(crypt)][Np^IICp″₃] [crypt = 2.2.2-cryptand, Cp″ = C₅H₃(SiMe₃)₂]. Density functional theory calculations indicate that the ground state electronic configuration of the Np²⁺ ion in the complex is 5f⁴6d¹.

Future Directions for Transuranic Single Molecule Magnets

Single Molecule Magnets (SMMs) based on transition metals and rare earths have been the object of considerable attention for the past 25 years. These systems exhibit slow relaxation of the magnetization, arising from a sizeable anisotropy barrier, and magnetic hysteresis of purely molecular origin below a given blocking temperature. Despite initial predictions that SMMs based on 5f-block elements could outperform most others, the results obtained so far have not met expectations. Exploiting the versatile chemistry of actinides and their favorable intrinsic magnetic properties proved, indeed, to be more difficult than assumed. However, the large majority of studies reported so far have been dedicated to uranium molecules, thus leaving the largest part of the 5f-block practically unexplored. Here, we present a short review of the progress achieved up to now and discuss some options for a possible way forward.

Non-aqueous neptunium and plutonium redox behaviour in THF – access to a rare Np(iii) synthetic precursor

Redox stability of tetravalent Np and Pu in THF is explored, leading to facile access routes into anhydrous Np(iii) chemistry.

Transuranic Computational Chemistry

Recent developments in the chemistry of the transuranic elements are surveyed, with particular emphasis on computational contributions. Examples are drawn from molecular coordination and organometallic chemistry, and from the study of extended solid systems. The role of the metal valence orbitals in covalent bonding is a particular focus, especially the consequences of the stabilization of the 5f orbitals as the actinide series is traversed. The fledgling chemistry of transuranic elements in the +II oxidation state is highlighted. Throughout, the symbiotic interplay of experimental and computational studies is emphasized; the extraordinary challenges of experimental transuranic chemistry afford computational chemistry a particularly valuable role at the frontier of the periodic table.