In‐ and Out‐of‐Cavity Interactions by Modulating the Size of Ruthenium Metallarectangles

Abstract

[pyridine] linkers are able to host an anthracene, pyrene, perylene, or coronene molecule in their cavity, while the medium-size metallarectangles 7 -9 incorporating 4,4'-bipyridine linkers are only able to encapsulate anthracene. However, out-of-cavity interactions are observed between these 4,4'-bipyridine-containing rectangles and pyrene, perylene, or coronene. In contrast, the small pyrazine-containing metallarectangles 4 -6 show no interaction in solution with this series of planar aromatic molecules.Introduction. -Half-sandwich complexes of ruthenium (Ru) and to a lesser extent osmium (Os) have received considerable attention, especially as catalysts [1], as biological agents [2], and recently as building blocks in supramolecular chemistry [3]. Their ability to generate a pre-organized arrangement with appropriate multidentate bridging ligands and rigid linkers have allowed the controlled formation of various supramolecular constructions, such as metallacycles [4], metallarectangles [5], metallaprisms [6], and metallacubes [7].In coordination and organometallic chemistry, quinones are attracting a lot of interest [8]. Their numerous applications in organic chemistry [9], physical chemistry [10], and biology [11] are well known, and moreover, these multifunctional ligands are becoming popular for the synthesis of complexes with (h 6 -arene)ruthenium units [12]. The commercially available quinone derivatives, 5,8-dihydroxy-1,4-naphthoquinone (H 2 dhnq), 9,10-dihydroxy-1,4-anthraquinone (H 2 dhaq), and 6,11-dihydroxynaphthacene-5,12-dione (H 2 dhtq) have been used to form dinuclear species with Ru metals [13]. However, the corresponding dinuclear complexes incorporating [Ru(h 6 -arene)]

Exploiting Natural Products to Build Metalla-Assemblies: The Anticancer Activity of Embelin-Derived Rh(III) and Ir(III) Metalla-Rectangles

“…The difference between the chemical shifts of the C 6 HRO 4 proton within these two isomers was more pronounced in the pyrazine derivatives 3 and 4 ( = 8 Hz), than in the 4,4'-bipyridine metalla-rectangles 5 and 6 ( = 3 Hz). This behavior was rationalized from the relative size of these metalla-rectangles [17]. In 3 and 4 the two μ 4 -C 6 HRO 4 -κO units were only separated by pyrazine linkers (M···M ≈ 7.0 Å), thus showing a greater discrepancy between the two isomers.…”

Enhancement of Cytotoxicity by Combining Pyrenyl-Dendrimers and Arene Ruthenium Metallacages

“…24 The bands observed between 500 and 700 nm are due to the quinonato linkers of the metallaclips. 25 Figure 3 illustrates these electronic absorptions with the spectra of the [guest⊂1] 6+ systems. Interestingly, the four characteristic bands of the pyrenyl part found in the region 290−390 nm are much stronger in the encapsulated systems than in the spectra of the free pyrenyl derivatives.…”

Permanent Encapsulation or Host–Guest Behavior of Aromatic Molecules in Hexanuclear Arene Ruthenium Prisms

“…Similarly, the proton signals of the 9,10-dioxo-9,10-dihydroanthracene-1,4-diolato and 6,11-dioxo-6,11-dihydronaphth- [8,9] whereas the methyl, isopropyl, and phenyl signals of the p-cymene ligands remain almost unchanged.…”

“…The corresponding dinuclear arene ruthenium complex [Ru 2 (p-cymene) 2 (doaq)Cl 2 ] [8] or [Ru 2 (p-cymene) 2 (dotq)Cl 2 ] [9] reacts in methanol at room temperature in the presence of silver trifluoromethanesulfonate (halide scavenger) with tpt (donor ligand) to give the metallahexanuclear cation [1] 6+ or [2] 6+ isolated as the trifluoromethanesulfonate salt in good yield (≈80 %, Scheme 1). The addition of one equivalent of phenanthrene, pyrene, triphenylene, or coronene leads to the direct encapsulation of the aromatic molecule in the metallaprism, following the same procedure but with a slightly better yield (≈85 %), possibly due to the template effect (Scheme 1).…”