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- Poly(alkylidenimine) Dendrimers Functionalized with the Organometallic Moiety [Ru(η5-C5H5)(PPh3)2]+ as Promising Drugs Against Cisplatin-Resistant Cancer Cells and Human Mesenchymal Stem CellsPublication . Gouveia, Marisol; Figueira, João; Jardim, Manuel G.; Castro, Rita; Tomás, Helena; Rissanen, Kari; Rodrigues, JoãoHere and for the first time, we show that the organometallic compound [Ru(η5-C5H5)(PPh3)2Cl] (RuCp) has potential to be used as a metallodrug in anticancer therapy, and further present a new approach for the cellular delivery of the [Ru(η5-C5H5)(PPh3)2]+ fragment via coordination on the periphery of low-generation poly(alkylidenimine) dendrimers through nitrile terminal groups. Importantly, both the RuCp and the dendrimers functionalized with [Ru(η5-C5H5)(PPh3)2]+ fragments present remarkable toxicity towards a wide set of cancer cells (Caco-2, MCF-7, CAL-72, and A2780 cells), including cisplatin-resistant human ovarian carcinoma celllines(A2780cisRcells). Also,RuCpandthepreparedmetallodendrimersareactiveagainsthuman mesenchymal stem cells (hMSCs), which are often found in the tumor microenvironment where they seem to play a role in tumor progression and drug resistance.
- A convenient route for the preparation of the monohydride catalyst trans-[RuCl(H)(dppe)2] (dppe=Ph2PCH2CH2PPh2): improved synthesis and crystal structurePublication . Figueira, João; Jardim, Manuel G.; Rodrigues, João; Valkonen, Arto; Rissanen, KariA novel and improved room temperature synthesis of the monohydride catalyst trans-[RuCl(H)(dppe)2] complex (1, dppe (1,2-bis(diphenylphosphino)ethane) = Ph2PCH2CH2PPh2) proceeds through oxidation of methanol (the solvent) by the pentacoordinated cis-[RuCl(dppe)2][PF6] complex and t-BuOK as the base is described. Compound 1 was fully characterized by NMR (1H, 13C, 31P), ESI-MS(TOF +), FTIR and elemental analysis. The X-ray structure of 1 was reported for the first time and unambiguously confirms the trans-configuration of the complex.
- Synthesis, characterization and solid-state photoluminescence studies of six alkoxy phenylene ethynylene dinuclear palladium(II) rodsPublication . Figueira, João; Czardybon, Wojciech; Mesquita, José Carlos; Rodrigues, João; Lahoz, Fernando; Russo, Luca; Valkonen, Arto; Rissanen, KariA rare family of six discrete binuclear [PdCl(PEt3)2] phenylene ethynylene rods with alkoxy side chains (methoxy, ethoxy and heptoxy) have been developed, and their solid-state photoluminescence results have been presented and discussed. The shorter bridging ligands are of the general formula H–CuC– C6H2(R)2–CuC–H, where R = H, OCH3, OC 2H5, and OC7H15, whereas the longer ones are based on H– CuC–C6H4–CuC–C6H2(R)2–CuC–C6H4–CuC–H, where R = OCH3, OC 2H5. These ligands display increasing length in both the main dimension (backbone length) as well as the number of carbons in the side chains (R, alkoxide side chain) that stem from the central phenylene moiety. The X-ray crystal structures of two of the prepared complexes are reported: one corresponds to a shorter rod, 1,4-bis[trans(PEt3)2ClPd-CuC]-2,5-diethoxybenzene (6c), while the second one is associated with a longer rod, the binuclear complex 1,4-bis[trans-(PEt3)2ClPd-4-(–CuC–C6H4–CuC)]-2,5-diethoxybenzene (7c). All new compounds were characterized by NMR spectroscopy (1H, 13C{1H} and 31P{1H}) as well as ESI-MS(TOF), EA, FTIR, UV-Vis, cyclic voltammetry and solid-state photoluminescence. Our work shows the influence of the alkoxy side chains on the electronic structure of the family of binuclear Pd rods by lowering its oxidation potential. In addition to this, the increase of the length of the bridge results in a higher oxidation potential. Solid state photoluminescence results indicate that Pd complexes are characterized by a marked decrease in both the emission intensity and the fluorescence lifetime values as compared to their ligands. This behaviour could be due to some degree of ligand-to-metal charge transfer.
- Poly(alkylidenamines) dendrimers as scaffolds for the preparation of low-generation ruthenium based metallodendrimersPublication . Rodrigues, João; Jardim, Manuel G.; Figueira, João; Gouveia, Marisol; Tomás, Helena; Rissanen, KariThe aim of this article is to highlight the use of nitrile-functionalized poly(alkylidenamines) dendrimers as building blocks for the preparation of low-generation ruthenium based cationic metallodendrimers having in view potential biomedical applications. Air-stable poly(alkylidenamines) nitrile dendrimers, peripherally functionalized with the ruthenium moieties [Ru(Z5-C5H5)(PPh3)2]+ or [RuCl(dppe)2]+, have been prepared, characterized and are being studied for their anticancer activity. The followed strategy is based on the biological advantages associated with low-generation dendrimers, the known activity of ruthenium compounds as anticancer drugs and the stability of these dendrimers at the physiological temperature.