New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide

Abstract

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

Thorium- and uranium-azide reductions: a transient dithorium-nitride versus isolable diuranium-nitrides

“…Accordingly, treatment of [M(Tren DMBS )(I)] (M = U, 1 ; Th, 2 )17 with excess NaN 3 or KN 3 affords [{M(Tren DMBS )(μ-N 3 )} n ] (M = U, n = 4, 3 ; Th, n = 3, 4 ) as green-yellow and colourless crystalline solids after work-up in isolated yields of 35 and 86%, respectively, Schemes 1 and 2 18. The combined characterisation data support the formulations of 3 and 4 , in particular the ATR-IR spectra of 3 and 4 both exhibit strong absorptions at 2131 cm –1 , which is characteristic of actinide-bound bridging-azide ligands 10b,c,19. The magnetic moment of 3 , Fig.…”

“…It would seem that the N–Th–N angle can close at the larger metal without as much inter-azide clashing due to longer Th–N bonds placing the azides further apart from one another, which accounts for the aggregation states of 3 and 4 . The U– and Th–N azide distances in 3 and 4 are longer than in terminal azide complexes,19 and we note that they are longer when trans to a Tren DMBS amide centre ( 3 , 2.540(5); 4 , 2.609(8) Å av.) than amine centre ( 3 , 2.425(5); 4 , 2.478(7) Å av.…”

Thorium-nitrogen multiple bonds provide evidence for pushing-from-below for early actinides

“…This can be observed in the ATR-IR data of 2 and 2 15 N (see Supplementary Fig. 1), which exhibit azide asymmetric stretching absorptions at 2086 and 2082/2070 cm −1 , respectively, which compare well to the azide stretch of 2086 cm −1 for [U(Tren TIPS )(N 3 )] 70 and other thorium-azides generally 77,78 . All other characterisation data for 2 and 2 15 N are unremarkable and support for the proposed formulations (see Supplementary Figs.…”

Unique Four-Electron Metal-to-Cage Charge Transfer of Th to a C82 Fullerene Cage: Complete Structural Characterization of Th@C3v(8)-C82

“…The short Th–cage contacts also occur between Th1 and cage carbons C03E, C14E, and C16E with the distances ranging from 2.411(9) to 2.494(10) Å, suggesting a significant metal–cage interaction. Note that such a Th···C orientation is very different from that observed for conventional (C 5 Me 5 ) 3 ThH or (C 5 Me 5 ) 2 ThX 2 complexes, in which the metal is centered over the cyclopentadienide ring with a Th–(ring centroid) distance of around 2.5 Å. − The metal···cage orientation in Th@C 82 is also unlike that observed for the majority of lanthanide EMFs (i.e., M@ C 2 v (9)-C 82 , M = La, Ce, Gd, Sm, etc. ), ,− in which the endohedral metal is residing under a hexagon.…”