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Characterizing Pressure‐Induced Uranium CH Agostic Bonds
Author(s) -
Arnold Polly L.,
Prescimone Alessandro,
Farnaby Joy H.,
Mansell Stephen M.,
Parsons Simon,
Kaltsoyannis Nikolas
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201411250
Subject(s) - agostic interaction , chemistry , natural bond orbital , steric effects , crystallography , ligand (biochemistry) , density functional theory , metal , atoms in molecules , molecule , computational chemistry , stereochemistry , organic chemistry , biochemistry , receptor
The diuranium(III) compound [UN′′ 2 ] 2 (μ‐η 6 :η 6 ‐C 6 H 6 ) (N′′=N(SiMe 3 ) 2 ) has been studied using variable, high‐pressure single‐crystal X‐ray crystallography, and density functional theory . In this compound, the low‐coordinate metal cations are coupled through π‐ and δ‐symmetric arene overlap and show close metalCH contacts with the flexible methyl CH groups of the sterically encumbered amido ligands. The metal–metal separation decreases with increasing pressure, but the most significant structural changes are to the close contacts between ligand CH bonds and the U centers. Although the interatomic distances are suggestive of agostic‐type interactions between the U and ligand peripheral CH groups, QTAIM (quantum theory of atoms‐in‐molecules) computational analysis suggests that there is no such interaction at ambient pressure. However, QTAIM and NBO analyses indicate that the interaction becomes agostic at 3.2 GPa.