Oxygen Atom Transfer and Intramolecular Nitrene Transfer
in a Rhenium β‑Diketiminate Complex
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Abstract
We present two routes to the oxo
rhenium complex OReCl<sub>2</sub>(BDI) (<b>1</b>) (BDI = <i>N</i>,<i>N</i>′-bis(2,6-diisopropylphenyl)-β-diketiminate)
and discuss the properties and reactivity of this material. Several
adducts of <b>1</b> with DMAP (<b>1-DMAP</b>; DMAP = 4-dimethylaminopyridine),
isonitriles (<b>1-XylNC</b>; XylNC = 2,6-dimethylphenyl isocyanide),
and phosphines (<b>1-PEt</b><sub><b>3</b></sub>; PEt<sub>3</sub> = triethylphosphine) were isolated and characterized. Additionally,
to probe the ancillary limitations of the BDI framework in high-valent
rhenium complexes, oxygen atom transfer (OAT) reactivity with <b>1</b> was pursued. It was found that under thermolysis conditions
OAT between <b>1</b> and PEt<sub>3</sub> was observed by NMR
spectroscopy, which indicated the formation of a new species, (ArN)ReCl<sub>2</sub>(MAD)(PEt<sub>3</sub>) (<b>2</b>; Ar = 2,6-diisopropylphenyl,
MAD = 4-((2,6-diisopropylphenyl)imino)pent-2-enide). A mechanism for
the generation of <b>2</b> involving nitrene transfer to rhenium
from the BDI ligand is proposed. X-ray crystal structures of complexes <b>1</b>, <b>1-PEt</b><sub><b>3</b></sub>, <b>1-DMAP</b>, and <b>2</b> were determined and are discussed in detail
