title: Diastereomerization Dynamics of a Bistridentate Ru(II) Complex.
abstract: The unsymmetrical nature of a new tridentate ligand bis(quinolinyl)-1,3-pyrazole (DQPz) is exploited in a bistridentate Ru(II) complex [Ru(DQPz)2](2+) to elucidate an unexpected dynamic diastereomerism. Structural characterization based on a combination of nuclear magnetic resonance spectroscopy and density functional theory calculations reveals the first quantifiable diastereomerization dynamics for Ru complexes with fully conjugated tridentate heteroaromatic ligands. A mechanism that involves a large-scale twisting motion of the ligands is proposed to explain the dynamic interconversion between the observed diastereomers, and the analysis of both experiments and calculations reveals a potential energy landscape with a transition barrier for the diastereomerization of ∼70 kJ mol(-1). The structural flexibility demonstrated around the central transition metal ion has implications for integration of complexes into catalytic and photochemical applications.
authors.forename: Martin
authors.initials: M
authors.lastname: Jarenmark
authors.forename: Göran
authors.initials: G
authors.lastname: Carlström
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Fredin
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.
authors.forename: Joachim
authors.initials: J
authors.lastname: Hedberg Wallenstein
authors.forename: Isa
authors.initials: I
authors.lastname: Doverbratt
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Abrahamsson
authors.forename: Petter
authors.initials: P
authors.lastname: Persson