Reaction of (bisimido)niobium(V) complexes with organic azides: [3 + 2] cycloaddition and reversible cleavage of β-diketiminato ligands involving nitrene transfer

Andreas H Obenhuber; Thomas L Gianetti; Xavier Berrebi; Robert G Bergman; John Arnold

doi:10.1021/ja413194z

Reaction of (bisimido)niobium(V) complexes with organic azides: [3 + 2] cycloaddition and reversible cleavage of β-diketiminato ligands involving nitrene transfer

J Am Chem Soc. 2014 Feb 26;136(8):2994-7. doi: 10.1021/ja413194z. Epub 2014 Feb 17.

Authors

Andreas H Obenhuber¹, Thomas L Gianetti, Xavier Berrebi, Robert G Bergman, John Arnold

Affiliation

¹ Department of Chemistry, University of California , Berkeley, California 94720, United States.

PMID: 24524190
DOI: 10.1021/ja413194z

Abstract

We describe the unusual reactivity of a highly labile diethyl ether adduct of an asymmetric niobium(V) bis(imide) 2.OEt2 containing the monoazabutadiene (MAD) ligand. This species undergoes clean nitrene transfer on treatment with tert-butyl- or di-isopropylphenyl azide resulting in the unprecedented reformation of nacnac ligands bound to the metal center. Corresponding reactions with trimethylsilyl- or tert-butyl azide allowed the isolation of two rare intermediates prior to N2 loss; mechanistic studies support the involvement of two different niobium species.