| Summary: | The coordination chemistry of an electron-rich macrocyclic CNC pincer-ligand consisting of two pentamethylene tethered N-heterocyclic carbene moieties on a carbazole backbone (bimca<sup>C5</sup>) is investigated by mainly NMR spectroscopy and X-ray crystal structure analysis. A bridging coordination mode is found for the lithium complex. With the larger and softer potassium ion, the ligand adopts a facial coordination mode and a polymeric structure by intermolecular potassium nitrogen interactions. The facial coordination is also confirmed at a Cp*Ru fragment, while C-H activation under dehydrogenation at the alkyl chain is observed upon reaction with [Ru(PPh<sub>3</sub>)<sub>3</sub>Cl<sub>2</sub>]. In contrast, Pd(OAc)<sub>2</sub> reacts under C-H activation at the central carbon atom of the pentamethylene tether to an alkyl-pincer macrocycle.
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