Browsing by Author "Jardim, Manuel G."
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- 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.
- Divergent route to the preparation of hybrid Pt–Fe 2,4,6-Tris(4-ethynyl)phenyl-1,3,5-triazine metallodendrimers for nonlinear opticsPublication . Maiti, Swarup K.; Jardim, Manuel G.; Rodrigues, João; Rissanen, Kari; Campo, Jochen; Wenseleers, WimThe synthesis strategy for the preparation of novel platinum acetylide homometallic and heterobimetallic dendrimers (containing Fe as the other metal fragment) based on a 2,4,6-tris(4-ethynyl)phenyl-1,3,5-triazine core (3) is reported. All the dendrimer generations (G0−G2) were synthesized under copper-free conditions following a divergent route. The G0-Pt dendrimer (4) was synthesized using the 1,3,5-triazine core (3) and cis[Pt(PEt3)2Cl2] with a molar ratio of 1/4. The advantage of the current method is that different dendrimers can be prepared by following the same procedure with only changes in the molar ratios of the reactants involved. For instance, when 3 reacts with 4 in a 4/1 molar ratio, the G1 dendrimer 7 is afforded without the peripheral Pt moiety, but the G1 dendrimer with the peripheral Pt moiety (8) is formed when 3 reacts with 4 in a 1/3 molar ratio. On the other hand, the G2 dendrimer with a peripheral Pt moiety (9) is synthesized when 7 reacts with 4 in a 1/6 molar ratio. The heterobimetallic dendrimers were synthesized up to generation 1 by capping the corresponding Pt dendrimers with the ethynylferrocenyl group (EFC). The respective G0 (6)- and G1-capped (10) dendrimers were synthesized when EFC reacted with 4 and 8 in molar ratios of 9/1 and 18/1, respectively. Nonlinear optical (NLO) polarizabilities measured by hyper-Rayleigh scattering (HRS) have been evaluated for the core 3, for the G0 dendrimer 4, and for the G0 dendrimer capped with EFC (6). In spite of the fact that the stability of the higher generations in chloroform is too low to allow HRS measurements, the reported NLO results show a remarkable enhancement (plus 50%) upon capping the zero dendrimer generation (6), reflecting the importance of the introduction of electron donor organometallic capping groups in the hyperpolarizabilities of the resulting dendrimers.
- 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.
- 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.
- Preparation and characterization of novel poly(alkylidenamine) nitrile ruthenium metallodendrimersPublication . Jardim, Manuel G.; Rissanen, Kari; Rodrigues, JoãoComplete functionalization of N,N,N ,N -[tetrakis(cyanoethyl)hexamethylenediamine] [N C(CH2)2]2N(CH2)6N[(CH2)2C N]2 (4) and N,N,N ,N -[tetrakis(cyanoethoxypropyl)hexamethylenediamine] [N C(CH2)2O(CH2)3]2N(CH2)6N[(CH2)3O(CH2)2C N]2 (7) with the organometallic moiety [Ru(η5C5H5)(PPh3)2Cl] and the five-coordinate cis-[RuCl(dppe)2][PF6] [dppe = 1,2-bis(diphenylphosphanyl)ethane] was attained with good yield, respectively, by treating the metallofragment with the core in methanol (at room temperature and in presence of TlPF6 as a chloride abstractor) and in 1,2 dichloroethane (under reflux). These novel nitrile-functionalized poly(alkylidenamine) dendrimers peripherally functionalized with the ruthenium moieties [Ru(η5-C5H5)(PPh3)2]+ and [RuCl(dppe)2]+ (8–11) were fully characterized by NMR (1H, 13C, 31P), TOF-MS and FTIR. The present results represent a step forward in the knowledge of the most adequate synthetic strategy for total coordination of poly(alkylidenamine) nitrile core derivatives to the different ruthenium complex moieties and confirm the versatility of these systems as building blocks in metallodendrimer chemistry.