14-Coordinate uranium(IV). Structure of uranium borohydride by single-crystal neutron diffraction

Quantum Simulation Verifies the Stability of an 18‐Coordinated Actinium–Helium Complex

“…It is knownt hat actinidei ons form complexes with high CNs. Amongt hose founde xperimentally are twelve-coordinated uranium in [U(NO 3 ) 6 ] 2À , [7] twelve-coordinated thorium in [Th(NO 3 ) 6 ] 2À , [8] fourteen-coordinated uranium in U(BH 4 ) 4 , [9] and fifteen-coordinated thorium in Th(H 3 BNMe 2 BH 3 ) 4 . [10] Ar ecent quantum chemical study by Kaltsoyannis [11] reported ar ecord-high coordination number of 17 for actinide-helium com-plexesA c 3 + -He 17 ,Th 4 + -He 17 ,and Pa 4 + -He 17 .…”

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H3BNMe2BH3)4]

“…[11] Very high Werner coordination numbers are seen for metal complexes of the borohydride anion BH 4 À , [12,13] which can coordinate to a single metal through as many as three hydrogen atoms. Accordingly, [Zr(BH 4 ) 4 ], [15][16][17] [Hf(BH 4 ) 4 ], [15,16,18] [Np-(BH 4 ) 4 ], [19] and [Pu(BH 4 ) 4 ], [19] all have coordination numbers of 12, and [Th(BH 4 ) 4 ], [15,16] [Pa(BH 4 ) 4 ], [19] and [U(BH 4 ) 4 ], [20] all of which are polymers in the solid state, have coordination numbers of 14. Accordingly, [Zr(BH 4 ) 4 ], [15][16][17] [Hf(BH 4 ) 4 ], [15,16,18] [Np-(BH 4 ) 4 ], [19] and [Pu(BH 4 ) 4 ], [19] all have coordination numbers of 12, and [Th(BH 4 ) 4 ], [15,16] [Pa(BH 4 ) 4 ], [19] and [U(BH 4 ) 4 ], [20] all of which are polymers in the solid state, have coordination numbers of 14.…”

Seventeen‐Coordinate Actinide Helium Complexes

“…This has been seen very recently in the experimental work of Pollak et al, [2] who found 16 Cs···F contacts in Cs[H 2 NB 2 (C 6 F 5 ) 6 ], and that by Popov et al in CoB 16 À , [3] and has also been predicted theoretically by Gu et al [4] forM @Li 16 (M = Ca, Sr, Ba, Ti,Z r, and Hf). The record for the actinide elements stood at 14 for many years (in U(BH 4 ) 4 ), [5] but is now 15, established experimentally by Daly et al for Th(H 3 BNMe 2 BH 3 ) 4 , [6] although the same authors used density functional theory (DFT) to predict that in the gas phase the number of Th···H contacts could rise to 16. All of these contributions bar Ref. [5] make reference to the work of Hermann et al [7] who,i n2 007, published aD FT survey of the geometric structures of Pb 2+ coordinated by He atoms.T he maximum value of n in PbHe n 2+ was found to be 15, with no true minimum structures being located for n > 15 in which all the He atoms are located in the first shell around the Pb.Intriguingly,buried at the end of the Methods Section, Hermann et al write "Wen ote that higher coordination number might be expected for charged actinide-He interactions".…”

“…The record for the actinide elements stood at 14 for many years (in U(BH 4 ) 4 ), [5] but is now 15, established experimentally by Daly et al for Th(H 3 BNMe 2 BH 3 ) 4 , [6] although the same authors used density functional theory (DFT) to predict that in the gas phase the number of Th···H contacts could rise to 16. All of these contributions bar Ref. [5] make reference to the work of Hermann et al [7] who,i n2 007, published aD FT survey of the geometric structures of Pb 2+ coordinated by He atoms.T he maximum value of n in PbHe n 2+ was found to be 15, with no true minimum structures being located for n > 15 in which all the He atoms are located in the first shell around the Pb.Intriguingly,buried at the end of the Methods Section, Hermann et al write "Wen ote that higher coordination number might be expected for charged actinide-He interactions". Ican now report that this suggestion is correct, and that computationally stable one-shell AnHe n q+ structures exist for Ac 3+ ,T h 4+ ,a nd Pa 4+ in which n = 17, an ew record coordination number.…”