(NII) Novel Catalytic, Synthesis Methods for Main Group
Abstract
In our efforts to develop reactive group 5 systems, we discovered that the combination of an imido group and the Beta-diketiminate (BDI) ligand provides a robust platform to support low-valent niobium complexes. We have since discovered that these well-defined niobium (III) complexes, in which low-valent Nb is stabilized by a labile arene ligand, are capable of activating fluoroaromatic substrates. The C-F activation shows unusual substrate selectivity in comparison with late transition metal compounds that activate C-F bonds. Under appropriate conditions, this hydride fluorination reaction has been rendered catalytic for fluorobenzene, as well as for 1,2- and 1,3-difluorobenzene, releasing benzene and fluorobenzene respectively. We have also been able to use these low-valent niobium systems to access niobium bis(imido) systems that are reactive across their metal-nitrogen pi-bonds. Recently, we have observed that these niobium bis (imido) complexes react reversibly with H2 and irreversibly with silanes via 1,2-addition. We have also observed that these bis (imido) compounds react with aryl isocyanides to exchange nitrene fragments between a tert-buty imido group and the isocyanide. DFT calculations suggest that this reaction proceeds through a [2 2]-like transition state.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 23, 2014
- Accession Number
- AD1013212
Entities
People
- Dean F. Toste
- John Arnold
- Robert Bergman
Organizations
- University of California Regents