NHC adducts of the stannylene Trip2 Sn (Trip=2,4,6-triisopropylphenyl) were reacted with zero-valent Ni, Pd, and Pt precursor complexes to cleanly yield the respective metal complexes featuring a three-membered ring moiety Sn-Sn-M along with carbene transfer onto the metal and complete substitution of the starting ligands. Thus the easily accessible NHC adducts to stannylenes are shown to be valuable precursors for transition-metal complexes with an unexpected SnSn bond. The complexes have been studied by X-ray diffraction and NMR spectroscopy as well as DFT calculations. The compounds featuring the structural motif of a distannametallacycle comprised of a [(NHC)2 M(0) ] fragment and Sn2 Trip4 represent rare higher congeners of the well-known olefin complexes. DFT calculations indicate the presence of a π-type Sn-Sn interaction in these first examples for acyclic distannenes symmetrically coordinating to a zero-valent transition metal.
Keywords: coordination chemistry; distannenes; nickel; palladium; platinum.
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