Synthesis, Structure, and Coordination Chemistry of
Phosphine-Functionalized Imidazole/Imidazolium Salts and Cleavage
of a C–P Bond in an NHC–Phosphenium Salt using a Pd(0)
Precursor
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Abstract
A simple
method involving metal–halogen exchange reaction(s)
to prepare various phosphine-functionalized imidazole/imidazolium
salts and their coordination chemistry with different metal precursors
has been described. Interestingly, the reaction of 1,3-dimethyl-2-(diphenylphosphino)-4-iodoimidazolium
iodide (<b>6</b>) with Pd<sub>2</sub>(dba)<sub>3</sub> in the
presence of triphenylphosphine affords a Pd(II)–NHC complex
which involves the cleavage of a C–P bond presumably occurring
via oxidative addition of Pd(0) to a C–I bond to afford an
in situ generated Pd(II) species, which subsequently reacts with another
1 equiv of <b>6</b> through the phosphine center to form an
adduct followed by a dephosphinylation reaction