Characterizing Pressure‐Induced Uranium CH Agostic Bonds1. (16th April 2015)

• Record Type: Journal Article
• Authors: Arnold, Polly L.; Prescimone, Alessandro; Farnaby, Joy H.; Mansell, Stephen M.; Parsons, Simon; Kaltsoyannis, Nikolas
• Is Part Of: Angewandte Chemie. Volume 127:Number 23(2015)
• Page Start: 6839
• Page End: 6843
• Publication Date: 2015-04-16
• Subjects: Actinoide -- Dichtefunktionalrechnungen -- Hochdruckchemie -- Röntgenbeugung -- Uran; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201411250
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The diuranium(III) compound [UN′′2 ]2 (μ‐η 6 :η 6 ‐C6 H6 ) (N′′=N(SiMe3 )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 metalCH 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.