Accession Number:

AD1013212

Title:

(NII) Novel Catalytic, Synthesis Methods for Main Group

Descriptive Note:

Technical Report,01 Sep 2013,31 Aug 2014

Corporate Author:

Regents of the University of California, Berkeley Berkeley

Personal Author(s):

• Bergman,Robert G.
• Arnold,John
• Toste,Dean F.

Report Date:

2014-12-23

Pagination or Media Count:

11.0

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 bisimido 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.

Descriptors:

• Niobium
• inorganic carbon compounds
• dielectric gases
• transition metals
• x ray crystallography
• chemical compounds
• fluorine
• substrates
• tantalum
• reactivities
• synthesis (chemistry)
• REAGENTS

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE