Jaime Ruiz Aranzaes

Cross Olefin Metathesis for the Selective Functionalization, Ferrocenylation, and Solubilization in Water of Olefin-Terminated Dendrimers, Polymers, and Gold Nanoparticles and for a Divergent Dendrimer Construction

Olefin cross metathesis was used to efficiently functionalize polyolefin dendrimers, polymers, and gold nanoparticles using the second-generation Grubbs catalyst. In these structures, the tethers were lengthened to prevent the facile cross metathesis that otherwise predominates in polyolefin dendrimers having short tethers. This synthetic strategy allows the one-step access to polyacid, polyester, and polyferrocenyl structures from polyolefins. Cross metathesis is also used to efficiently achieve an iterative divergent dendritic construction. All the cross metathesis reactions were monitored by 1H NMR showing the chemo-, regio-, and stereoselectivity. MALDI-TOF mass spectrometry was a very useful technique to confirm the efficiency of this synthetic strategy.

Four Generations of Water‐Soluble Dendrimers with 9 to 243 Benzoate Tethers: Synthesis and Dendritic Effects on Their Ion Pairing with Acetylcholine, Benzyltriethylammonium, and Dopamine in Water

Water-soluble benzoate-terminated dendrimers of four generations (from G0 with 9 branches to G3 with 243 branches) were synthesized and fully characterized. They form water-soluble assemblies by ion-pairing interactions with three cations of medicinal interest (acetylcoline, benzyltriethylammonium, and dopamine), which were characterized and investigated by 1H NMR spectroscopy, whereas such interactions do not provoke any significant shift of 1H NMR signals with the monomeric benzoate anion. The calculated association constants confirm that the dendritic carboxylate termini reversibly form ion pairs and aggregates. Diffusion coefficients and hydrodynamic diameters of the dendrimers, as well as changes thereof on interaction with the cations, were evaluated by DOSY experiments. The lack of increase of dendrimer size on addition of the cations and the upfield shifts of the 1H NMR signals of the cation indicate encapsulation within the hydrophobic dendrimer interiors together with probable backfolding of the benzoate termini.

Gold-nanoparticle-cored Polyferrocenyl Dendrimers: Modes of Synthesis and Functions as Exoreceptors of Biologically Important Anions and Re-usable Redox Sensors

Polyamidoferrocenylalkylthiolate-Au nanoparticles (AuNP) and AuNP-cored polyferrocenyl dendrimers have been assembled either by the ligand-substitution method from dodecanethiolate-AuNP (AB3 units) or Brust-type direct synthesis from a 1-1 mixture of dodecanethiol and dendronized thiol (AB9 units). The AuNP-cored polyferrocenyl dendrimers are a new type of dendrimers with a AuNP core. AuNPs containing a nonasilylferrocenyl dendron have been synthesized; they bear respectively 180 and 360 ferrocenyl units at the periphery. These AuNPs selectively recognize the anions H2PO4− and adenosine-5′-triphosphate (ATP2−) with a positive dendritic effect. Recognition is monitored by the appearance of a new wave at a less positive potential in cyclic voltammetry (CV). These AuNP-cored polyferrocenyl dendrimers can form robust modified electrodes that serve as re-usable sensors of ATP2− by simple washing with CH2Cl2.

Catalytically efficient palladium nanoparticles stabilized by “click” ferrocenyl dendrimers

1,2,3-Ferrocenyl triazole ligands generated by click reactions in dendrimers bind Pd(OAc)2 with a systematic one-to-one stoichiometry as monitored by titration using the ferrocenyl redox sensor attached to the triazole ring, and the dendritic PdII complexes formed are best reduced by methanol to form palladium nanoparticles of designed types and sizes that show excellent efficiency and selectivity in olefin hydrogenation.

Cytotoxic and Proinflammatory Effects of Metal-Based Nanoparticles on THP-1 Monocytes Characterized by Combined Proteomics Approaches.

Thorough characterization of toxic effects of nanoparticles (NP) is desirable due to the increasing risk of potential environmental contamination by NP. In the current study, we combined three recently developed proteomics approaches to assess the effects of Au, CuO, and CdTe NP on the innate immune system. The human monocyte cell line THP-1 was employed as a model. The anticancer drugs camptothecin and doxorubicin were used as positive controls for cell death, and lipopolysaccharide was chosen as a positive control for proinflammatory activation. Despite equivalent overall toxicity effect (50 ± 10% dead cells), the three NP induced distinctly different proteomics signatures, with the strongest effect being induced by CdTe NP, followed by CuO and gold NP. The CdTe toxicity mechanism involves down-regulation of topoisomerases. The effect of CuO NP is most reminiscent of oxidative stress and involves up-regulation of proteins involved in heat response. The gold NP induced up-regulation of the inflammatory mediator, NF-κB, and its inhibitor TIPE2 was identified as a direct target of gold NP. Furthermore, gold NP triggered activation of NF-κB as evidenced by phosphorylation of the p65 subunit. Overall, the combined proteomics approach described here can be used to characterize the effects of NP on immune cells.

New water-soluble polyanionic dendrimers and binding to acetylcholine in water by means of contact ion-pairing interactions

A new water-soluble polyanionic dendrimer containing 81 benzoate termini (diameter: 11+/-1 nm from DOSY NMR spectroscopy) has been synthesized; it interacts with acetylcholine cations in water-soluble assemblies in which each carboxylate terminus reversibly forms contact ion pairs and aggregates at the tether termini, as shown by 1H NMR spectroscopy.

Assembly between gold-thiolate nanoparticles and the organometallic cluster [Fe(η5-C5H5)(µ3-CO)]4 toward redox sensing of oxo-anions

Covalent assembly between gold-thiolate nanoparticles (AuNPs) and the cluster [Fe(eta(5)-C(5)H(5))(mu(3)-CO)](4), 1, can be achieved either by direct Brust-Schriffin-type synthesis using a mixture of undecanethiol and a thiol functionalized with , or by substitution of undecanethiolate ligands in AuNPs by thiolate ligands functionalized with ; cyclic voltammetry of these AuNPs functionalized with allows us to recognize and titrate the oxo-anions H(2)PO(4)(-) and ATP(2-).