Facile Changes in Bonding Modes of Azulene in Di- and Triruthenium Clusters upon Interaction with CO

Coordination-Induced Molecular Tweezing: Ruthenium Clusters Docked at Azuliporphyrinogens

The reaction of [Ru₃(CO)₁₂] with a series of conformationally flexible thiaazuliporphyrinogens, namely, dithiadiazuli-, thiatriazuli- and tetraazuliporphyrinogen, yielded a series of complexes with two azulene rings coordinated by either Ru₂(CO)₅ and Ru₄(CO)₉ or two Ru₄(CO)₉ clusters. For dithiadiazuliporphyrinogen, three fundamental arrangements were detected, with two clusters being located at the same side or different sides of the meso plane. Coordination altered the electron density on the rings, allowing for dispersion-promoted interactions between coordinated azulenes. To create this face-to-face arrangement, the ligand framework performs a tweezing movement with coordinated azulenes approaching each other. The tweezer-like arrangement of the coordinated azulene rings assists the formation of azulene inclusion complexes as determined by ¹H NMR titration.

[(η5-C5Me5)Ru]+ fragments ligated to polyaromatic hydrocarbons: an experimental and computational approach to pathways for haptotropic migration

DFT calculations indicated rather high activation energies for the thermally induced intramolecular inter-ring haptotropic migration of the [(η⁵-C₅Me₅)Ru⁺] moiety.