η⁵-Imidazolato Complexes of Ruthenium

Abstract

The imidazolato complexes [Cp*Ru(μ-η 1:η 1 -Ph 2 C 3 HN 2 )] 3, Cp*Ru(η 5 -Ph 2 C 3 HN 2 ), and Cp*Ru(η 5 -Me 2 C 3 HN 2 ) have been prepared and characterized. The latter complexes represent the first structural documentation of the η 5 -imidazolato ligand coordination mode to any metal. [Cp*Ru(μ-η 1:η 1 -Ph 2 C 3 HN 2 )] 3 converts to Cp*Ru(η 5 -Ph 2 C 3 HN 2 ) upon heating in tetrahydrofuran, demonstrating that the η 5 -imidazolato ligand is thermodynamically preferred over the μ-η 1:η 1 -ligand in the Cp*Ru(II) system.