U₂N@I_h(7)-C₈₀: fullerene cage encapsulating an unsymmetrical U(iv)NU(v) cluster

Abstract

For the first time, an actinide nitride clusterfullerene, U2N@Ih(7)-C80 was synthesized and fully characterized by X-ray single crystallography and multiple spectroscopic methods. U2N@Ih(7)-C80 is by far the first endohedral fullerene...

USc2C2 and USc2NC Clusters with U–C Triple Bond Character Stabilized Inside Fullerene Cages

“…30 The bond lengths for U1−C81A and U1− N81A are identical and measured as 2.163(4) Å, slightly longer than the U�C bond (2.033(5)/2.028(5) Å) in U 2 C@ I h (7)C 80 and the U�N bond (2.058(3)/1.943(3) Å) in U 2 N@I h (7)C 80 , but still within the length range of short U�C and U�N bonds. 19,31 This suggests that C and N are linked by U bridges to form a C�U�N bonding motif in USc 2 NC, a novel actinide cluster that has not been reported before.…”

“…In the low wavenumber range from 600 to 800 cm −1 , the calculations indicate that the frequency at 616 cm −1 is the concerted vibration of the U−C/ N bonds, which experimentally corresponds to the frequency at 638 cm −1 . Compared to the U−C bond vibration in U 2 C@ I h (7)-C 80 (785 cm −1 ) and the U−N bond vibration in U 2 N@ I h (7)-C 80 (788 cm −1 ), 19,31 this vibration is significantly shifted to higher frequency. The vibrational mode of 726 cm −1 is analogous to the 796 cm −1 mode (calculated) of the USc 2 C 2 cluster, which experimentally corresponds to the frequency at 733 cm −1 .…”

“…As shown in Figure b and Table , the bond lengths for Sc1A-C81A, Sc1A-N81A, Sc1B–C81A, and Sc1B–N81A of the endohedral USc 2 NC cluster are 2.095(4) Å, 2.126(4) Å, 2.115(5) Å, and 2.134(5) Å, respectively, which are slightly longer than those for Sc–C (2.053(6)/2.060(6) Å) in USc 2 C@ I h (7)-C 80 and the Sc–N bond (2.052(4)/2.038(3)/2.112(3) Å) in Sc 3 N@ C s (39663)-C 80 . The bond lengths for U1–C81A and U1–N81A are identical and measured as 2.163(4) Å, slightly longer than the UC bond (2.033(5)/2.028(5) Å) in U 2 C@ I h (7)­C 80 and the UN bond (2.058(3)/1.943(3) Å) in U 2 N@ I h (7)­C 80 , but still within the length range of short UC and UN bonds. , This suggests that C and N are linked by U bridges to form a CUN bonding motif in USc 2 NC, a novel actinide cluster that has not been reported before.…”

Continuous Shape Measures Study of the Coordination Spheres of Actinide Complexes – Part 1: Low Coordination Numbers

“…It has already been mentioned that monocoordinated metal atoms are unlikely in the solid state and in solution. [19] Consistently, the only two structures retrieved in a structural search for monocoordinated actinide atoms correspond to U atoms in U=N = U and CSc 2 U units encapsulated within a C 80 fullerene, whose rings are actually π-coordinated to uranium [20] and should not be considered as monocoordinated. In contrast, in the rarefied environment of the gas phase, a monocoordinated metal can retain its coordinative unsaturation thanks to the absence of nearby donor species.…”

Highly oxidized U(vi) within the smallest fullerene: gas-phase synthesis and computational study of boron-doped U@C27B

“…22–24 The carbon cages can be used as effective nanocontainers to study the elusive actinide-actinide bond, 25,26 as for example in Th 2 @I h (7)-C 80 , 24 or to encapsulate reactive or rare actinide clusters as in U 2 N@ I h (7)-C 80 , U 2 C@ I h (7)-C 80 , U 2 C 2 @ I h (7)-C 80 , U 2 C 2 @ D 3h (5)-C 78 and UCN@ C s (6)-C 82 . 27–30 The encapsulated actinides show a wide range of oxidation states, especially uranium, which is present as (i) U( v ) in U 2 C@ I h (7)-C 80 ; (ii) U( iv ) in U 2 C 2 @ I h (7)-C 80 or U@ C 1 (28324)-C 80 and most of the mono-uranofullerenes; and (iii) U( iii ) in U 2 @ I h (7)-C 80 , U@ C 2v (9)-C 82 or UCN@ C s (6)-C 82 , for which the authors claimed an ambiguous oxidation state, U( iii ) vs. U( i ). 28 The shortest U⋯C distances in all these uranofullerenes range between 2.40 and 2.55 Å, slightly shorter than in uranocene U(η 8 -C 8 H 8 ) 2 , U(η 5 -C 5 H 5 ) 4 or in arene-bridged diuranium complexes.…”