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Download fileSynthesis and Reactivity of Cobalt(I) and Iridium(I) Complexes Bearing a Pentadentate N‑Homoallyl-Substituted Bis(NHC) Pincer Ligand
journal contribution
posted on 2020-04-13, 19:51 authored by Yingying Tian, Theo Maulbetsch, Ronja Jordan, Karl W. Törnroos, Doris KunzTwo methods for the synthesis of
the bis(imidazolin-2-ylidene)carbazolide
cobalt(I) complex [Co(bimcaHomo)] (2) have
been developed. The first route relies on the direct transmetalation
of the in situ generated lithium complex [Li(bimcaHomo)] with CoCl(PPh3)3. The second route
is a two-step synthesis that consists of the transmetalation of [Li(bimcaHomo)] with CoCl2 followed by reduction of the Co(II)
complex to yield the desired Co(I) complex 2. The analogous
iridium complex [Ir(bimcaHomo)] (4) was prepared
by transmetalation of [Li(bimcaHomo)] or [K(bimcaHomo)] with [Ir(μ-Cl)(COD)]2. The catalytic activity
of complexes 2 and 4 in the epoxide isomerization
was tested in the absence and presence of H2. When [M(bimcaHomo)] (M = Ir (4), Rh (3)) was exposed
to 1 bar of H2 at 80 °C, single crystals formed whose
X-ray structure analyses revealed the hydrogenation of the N-homoallyl moieties and formation of the dimeric hydrido
complexes [Ir(bimcan‑Bu)(H)2]2 (7) and [Rh(bimcan‑Bu)(H)2]2 (8).
