Insights into metal borohydride and aluminohydride bonding: X-ray and neutron diffraction structures and a DFT and charge density study of [Na(15-crown-5)][EH(4)] (E = B, Al)

Peter Sirsch; Natascha L N Clark; Lenuţa Onuţ; Richard P L Burchell; Andreas Decken; G Sean McGrady; Aziz Daoud-Aladine; Matthias J Gutmann

doi:10.1021/ic1014187

Insights into metal borohydride and aluminohydride bonding: X-ray and neutron diffraction structures and a DFT and charge density study of [Na(15-crown-5)][EH(4)] (E = B, Al)

Inorg Chem. 2010 Dec 20;49(24):11395-402. doi: 10.1021/ic1014187. Epub 2010 Nov 19.

Authors

Peter Sirsch¹, Natascha L N Clark, Lenuţa Onuţ, Richard P L Burchell, Andreas Decken, G Sean McGrady, Aziz Daoud-Aladine, Matthias J Gutmann

Affiliation

¹ Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3. psirsch@unb.ca

PMID: 21090626
DOI: 10.1021/ic1014187

Abstract

The neutron and X-ray structures of [Na(15-crown-5)][BH(4)] and [Na(15-crown-5)][AlH(4)], respectively, are reported, along with a topological analysis of their DFT-computed charge densities that explores the bonding between the anionic complex hydride [EH(4)](-) (E = B, Al) and the counterion [Na(15-crown-5)](+). In each case, the interaction is weak and mainly electrostatic in nature; however, notable differences are observed in the manner in which [BH(4)](-) and [AlH(4)](-) bind to the metal, which explains their different coordination modes. A range of unconventional E-H···H-C contacts is revealed to play an important role in the overall bonding and crystal packing of both complexes. These interactions can be classified as weak dihydrogen bonds based on the atoms in molecules approach.