Coordination-Induced Molecular Tweezing: Ruthenium Clusters Docked at Azuliporphyrinogens

Abstract

The reaction of [Ru(CO)] with a series of conformationally flexible thiaazuliporphyrinogens, namely, dithiadiazuli-, thiatriazuli- and tetraazuliporphyrinogen, yielded a series of complexes with two azulene rings coordinated by either Ru(CO) and Ru(CO) or two Ru(CO) 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 H NMR titration.

Incorporation of a p‐Phenylene Unit into the Azuliporphyrinogens Frame—Oxidation and Ruthenium Cluster Coordination

“…Evidently, 6 a completes the group of previously investigated azuliporphyrinogen stereoisomers of higher symmetry . These macrocycles conserve the specific structural facet.…”

“…The analysis of 1 H NMR spectra collected for the crude reaction mixture and the result of purification indicated 6 a‐Ru as a major and only isolable product. Thus, reactivity of porphyrinogen 6 a followed the route previously explored for a series of azuliporphyrinogens . The coordination to two azulene units resulted in significant changes in NMR spectra (Figures S15 and S16).…”

“…Significantly, the BB coordination mode is the only one noticed in case of 6 a coordination. Till present the specific regioselectivity of the Ru 4 (CO) 9 cluster binding has been detected for: 3 ‐AA, 2 ‐AA, 1 ‐[AA, AB, BB], 6 a ‐BB …”

“…Here, we report on synthesis and characterization of 5,10,15,20‐tetra( p ‐tolyl)diazuli‐ p ‐benzithiaporphyrinogen stereoisomers and their oxidized derivatives. The introduction of one p ‐phenylene ring has been targeted to influence the diazuli‐ p ‐benzithiaporphyrinogen susceptibility toward oxidation, as well as to determine their coordination properties, established previously for azulene‐only macrocyclic systems . As a matter of fact such a modification leads to an expansion of macrocyclic frame and increases a number of carbon atoms in the cavity.…”

“…As a matter of fact such a modification leads to an expansion of macrocyclic frame and increases a number of carbon atoms in the cavity. Due to the presence of four C(sp 3 ) meso bridges introducing additional degrees of freedom the molecule can remain in a few distinguished conformations influencing appropriate crystal structures of such systems or coordination properties of isomers …”