TY - JOUR
T1 - Crystal structure of the uranium oxo borohydride complex U 2(μ-O)(BH 4) 6(dme) 2 (dme = 1,2-dimethoxyethane) and reformulation of U 2(μ-H) 2(BH 4) 6(dme) 2
AU - Daly, Scott R.
AU - Ephritikhine, Michel
AU - Girolami, Gregory S.
N1 - Funding Information:
S.R.D. and G.S.G. thank the National Science Foundation ( CHE07-50422 and DMR-0420768 ) and the PG Research Foundation for support of this research, and Scott Wilson and Teresa Wieckowska-Prussak at the George L. Clark X-ray facility at the University of Illinois for collecting the X-ray diffraction data. M.E. gratefully acknowledges support from the Centre National de la Recherche Scientifique (CNRS) and the Commissariat à l’Energie Atomique (CEA).
PY - 2012/2/9
Y1 - 2012/2/9
N2 - The reaction of uranium tetrachloride, UCl 4, with sodium N,N-dimethylaminodiboranate, Na(H 3BNMe 2BH 3), in refluxing 1,2-dimethoxyethane (dme) yields small amounts of a new complex, which we formulate as (μ-oxo)hexakis(tetrahydroborato)bis(1,2- dimethoxyethane)diuranium(IV), toluene solvate, U 2(μ-O)(BH 4) 6(dme) 2·C 7H 8, 1. Most likely, the formation of BH 4 - groups from H 3BNMe 2BH 3 - occurs with the elimination of [Me 2NBH 2] 2, and the formation of the oxo group involves adventitious hydrolysis. Each uranium center in 1 adopts a fac octahedral geometry (counting the BH 4 - groups as occupying one coordination site); the bridging oxygen atom and the two coordinated oxygen atoms of the dme ligand occupy positions trans to the three BH 4 - groups. The hydrogen atom positions were located in the electron density difference maps and reveal that all three BH 4 - groups are bound in a κ 3H fashion. The U⋯B distances to the two BH 4 - groups that are cis to the bridging oxygen atom are 2.574(6) and 2.584(6) , whereas the U⋯B distance of 2.635(7) to the BH 4 - group that is trans to the bridging oxygen is distinctly longer. Thus, the bridging oxygen atom exerts a noticeable trans influence. The crystallographic and 1H NMR data strongly suggest that the previously reported uranium hydride complex U 2(μ-H) 2(BH 4) 6(dme) 2 should be reformulated as this oxo complex U 2(μ-O)(BH 4) 6(dme) 2.
AB - The reaction of uranium tetrachloride, UCl 4, with sodium N,N-dimethylaminodiboranate, Na(H 3BNMe 2BH 3), in refluxing 1,2-dimethoxyethane (dme) yields small amounts of a new complex, which we formulate as (μ-oxo)hexakis(tetrahydroborato)bis(1,2- dimethoxyethane)diuranium(IV), toluene solvate, U 2(μ-O)(BH 4) 6(dme) 2·C 7H 8, 1. Most likely, the formation of BH 4 - groups from H 3BNMe 2BH 3 - occurs with the elimination of [Me 2NBH 2] 2, and the formation of the oxo group involves adventitious hydrolysis. Each uranium center in 1 adopts a fac octahedral geometry (counting the BH 4 - groups as occupying one coordination site); the bridging oxygen atom and the two coordinated oxygen atoms of the dme ligand occupy positions trans to the three BH 4 - groups. The hydrogen atom positions were located in the electron density difference maps and reveal that all three BH 4 - groups are bound in a κ 3H fashion. The U⋯B distances to the two BH 4 - groups that are cis to the bridging oxygen atom are 2.574(6) and 2.584(6) , whereas the U⋯B distance of 2.635(7) to the BH 4 - group that is trans to the bridging oxygen is distinctly longer. Thus, the bridging oxygen atom exerts a noticeable trans influence. The crystallographic and 1H NMR data strongly suggest that the previously reported uranium hydride complex U 2(μ-H) 2(BH 4) 6(dme) 2 should be reformulated as this oxo complex U 2(μ-O)(BH 4) 6(dme) 2.
KW - Aminodiboranate
KW - Borohydride
KW - Crystal structure
KW - Hydride
KW - Oxo
KW - Uranium
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U2 - 10.1016/j.poly.2011.11.003
DO - 10.1016/j.poly.2011.11.003
M3 - Article
AN - SCOPUS:84855837354
VL - 33
SP - 41
EP - 44
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
IS - 1
ER -