An Actinide Zintl Cluster: A Tris(triamidouranium)μ₃‐η²:η²:η²‐Heptaphosphanortricyclane and Its Diverse Synthetic Utility

Abstract

A diuranium(V) arene complex reductively cleaves P4 to give a triuranium heptaphosphanortricyclane cluster (see picture; U green, P purple, N blue, Si orange). This cluster is the first example of a molecular actinide [P7] Zintl complex and the first example of uranium‐promoted catenation of P4. This complex undergoes a wide range of reactions under mild conditions to afford liberated P7R3 phosphanortricyclanes.

Thorium(IV) and Uranium(IV) Phosphaazaallenes

“…In 1, the thorium-phosphido bond distances are similar to other metallocene thorium bis(phosphido) complexes reported and slightly shorter than the 2.855(6) and 2.938(6) Å in Th(Bc Mes )2[PH(Mes)]2 [33]. Complex 2 is the first structurally characterized bis(phosphido) uranium complex, however polyphosphide complexes of uranium are known from P4 activation [34,35]. The uranium-phosphido bond distances are shorter than those in U(Tren TIPS )(PH2) of 2.883(2) Å [36], but similar to the 2.789(4) Å in (C5Me5)2U[P(SiMe3)2](Cl) [14].…”

Crystalline Diuranium Phosphinidiide and μ‐Phosphido Complexes with Symmetric and Asymmetric UPU Cores

“…However the magnetic moment of 7 at 2 K is higher than the corresponding data for 3 , which may represent the relative crystal‐field effects on uranium(IV) from HP 2− versus P 3− ; the P 3− would be expected to present a greater point charge and splitting of the paramagnetic excited states manifold, so a low‐lying group are still populated to some extent at low temperature with a higher‐lying group at high temperature that are more difficult to populate. This notion is consistent with a slightly flatter magnetic trace at high temperature for 7 compared to 3 and has been noted in other uranium(IV) complexes with strong point‐charge ligands ,. Interestingly, counter to expectations the shoulder at about 25 K for the magnetic data of 3 is much less pronounced for 7 which is consistent with our suggestion that this feature is due to single ion crystal field effects and not magnetic exchange, though magnetic exchange cannot be completely ruled out.…”

Crystalline Diuranium Phosphinidiide and μ‐Phosphido Complexes with Symmetric and Asymmetric UPU Cores

“…Compounds 4 and 7 are unprecedented examples of uranium phosphido complexes outside of matrix isolation studies,and they rapidly decompose in solution underscoring the paucity of uranium phosphido complexes.I nterestingly, 4 and 7 feature symmetric and asymmetric UPU cores,r espectively,r eflecting their differing steric profiles.Inrecent years there has been burgeoning interest in the synthesis and chemistry of uranium-ligand multiple bonds, [1] which stems from adesire to better understand the chemical bonding of uranium and to correlate this to observed physicochemical properties.H owever,m ost progress has been made regarding complexes where uranium engages in af ormal multiple bond to C-/N-/O-based donor ligands,a nd examples of second row-centered, and beyond, donor ligands generally continue to be rare. [2] Where uranium-phosphorus multiple bonding is concerned, [3] only two structurally authenticated phosphinidene complexes have been reported, [4] and investigations into uranium phosphido com-plexes are exceedingly rare and restricted to cryogenic matrix isolation and/or computational studies. [5] Thus,t here are no reports of uranium phosphido complexes on macroscopic scales under conditions that would permit further investigation;i ndeed, the phosphido linkage,w hether terminal or mbridging,r emains ar elatively rare structural motif even in transition-metal chemistry.…”