Construction of Rhodium(I)
and Gold(I) Macrocycles
by Transferring a Phosphine-Functionalized 4,5-Diazafluorenide Ligand
from Its Copper(I) N-Heterocyclic Carbene Complex
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Abstract
We report the synthesis and characterization of a phosphine-functionalized
4,5-diazafluorene ligand, 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorene
(L<sub>p</sub>H), and its Cu(IPr) complex (IPr = <i>N,N</i>′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) [Cu(IPr)L<sub>p</sub>] (<b>2a</b>), which exhibits a monomeric structure
in solution but dimerizes in the solid state. Compound <b>2a</b> reacts with Rh(PPh<sub>3</sub>)<sub>3</sub>Cl, [Rh(COD)Cl]<sub>2</sub>, Au(SMe<sub>2</sub>)Cl, and Au(IPr)Cl to form the macrocyclic complexes
[Rh(PPh<sub>3</sub>)L<sub>p</sub>]<sub>2</sub> (<b>2b</b>),
[Rh(COD)L<sub>p</sub>]<sub>2</sub> (<b>2c</b>), and [AuL<sub>p</sub>]<sub>2</sub> (<b>2d</b>) and the mononuclear complex
[Au(IPr)L<sub>p</sub>] (<b>2f</b>), respectively, via ligand
transfer. Although <b>2b</b>–<b>d</b>,<b>f</b> could also be synthesized from the deprotonated ligand L<sub>p</sub><sup>–</sup> and the corresponding metal starting materials
directly, the reactions require longer time and give lower yields.
The reaction between L<sub>p</sub>H and Au(SMe<sub>2</sub>)Cl gives
Au(L<sub>p</sub>H)<sub>2</sub>Cl (<b>2e</b>) exclusively
