Ruthenium(II) Tris‐Pyrazolylmethane Complexes in Transfer Hydrogenation Reactions

Abstract

While ruthenium(II) arene complexes have been widely investigated for their potential in catalytic transfer hydrogenation, studies on homologous compounds replacing the arene ligand with the six‐electron donor tris(1‐pyrazolyl)methane (tpm) are almost absent in the literature. The reactions of [RuCl(κ3‐tpm)(PPh3)2]Cl, 1, with a series of nitrogen ligands (L) proceeded with selective PPh3 mono‐substitution, affording the novel complexes [RuCl(κ3‐tpm)(PPh3)(L)]Cl (L=NCMe, 2; NCPh, 3; imidazole, 4) in almost quantitative yields. Products 2–4 were fully characterized by IR and multinuclear NMR spectroscopy, moreover the molecular structure of 4 was ascertained by single crystal X‐ray diffraction. Compounds 2–4 were evaluated as catalytic precursors in the transfer hydrogenation of a series of ketones with isopropanol as the hydrogen source, and 2 exhibited the highest activity. Extensive NMR experiments and DFT calculations allowed to elucidate the mechanism of the transfer hydrogenation process, suggesting the crucial role played by the tpm ligand, reversibly switching from tri‐ to bidentate coordination during the catalytic cycle.

Complexes of Ruthenium(II) as Promising Dual-Active Agents against Cancer and Viral Infections

“…Bresciani et al (2023) [146] presented a study regarding the antitumor potential of several dinuclear Ru biscyclopentadienyl carbonyl complexes (23)(24)(25)(26) against A549 (lung), SW480 (colon), and A2780 and A2780cis (ovarian) cancer cell lines, as well as the nontumoral HEK-293 cell line. Cisplatin was used as the standard (IC 50 = 43 ± 3 µM, 35 ± 2 µM, 8.3 ± 1.4 µM, and 30 ± 3 µM, respectively, against cancer cell lines).…”

“…Among the precious metals, ruthenium (Ru) has singular physicochemical properties, which makes it particularly useful in drug design [19]. Ru complexes represent an important class of metallo-organic compounds with numerous applications, and they are currently used in the fields of catalysis [20][21][22][23], including homogeneous, heterogeneous, and photocatalysis [24]. Moreover, numerous biological activities, such as antifungal [25], antibacterial [26], and anticarcinogenic [27][28][29][30][31][32], have been described for the complexes of Ru, as well as their uses in neurodegenerative diseases [33].…”