Ilaria Giannicchi

Kinetics of demetallation of a zinc–salophen complex into liposomes

A Zn-salophen complex has been incorporated into POPC large unilamellar liposomes (LUV) obtained in phosphate buffer at pH 7.4. Fluorescence optical microscopy and anisotropy measurements show that the complex is located at the liposomal surface, close to the polar headgroups. The interaction of the POPC phosphate group with Zn(2+) slowly leads to demetallation of the complex. The process follows first order kinetics and rate constants have been measured fluorimetrically in pure water and in buffered aqueous solution. The coordination of the phosphate group of monomeric POPC with salophen zinc also occurs in chloroform as detected by ESI-MS measurements. The effect of the Zn-salophen complex on the stability of POPC LUV has been evaluated at 25°C by measuring the rate of release of entrapped 5(6)-carboxyfluorescein (CF) in the presence and in the absence of Triton X-100 as the perturbing agent. It turns out that the inclusion of the complex significantly increases the stability of POPC LUV.

Ion-Pair Recognition by Metal)Salophen and Metal)Salen Complexes

The development of heteroditopic receptor systems that can simultaneously bind cationic and anionic species is one of the most challenging research topics in supramolecular chemistry, attracting the attention of a large number of research groups worldwide. Such an interest is due especially to the fact that the overall receptor–ion-pair complex is neutral and this can be advantageous in many situations, such as salt solubilization and extraction, and membrane-transport applications. Receptors designed for ion-pair complexation are molecules comprising well-known anion-binding motifs and familiar cation-binding sites. An important family of compounds that can use metal Lewis-acidic centres for anion recognition and that can be easily derivatized to introduce an additional binding site for the cation is metal–salophen and metal–salen complexes. This short review shows that the high versatility of salen and salophen ligands and of the corresponding metal complexes allows, through simple modifications of the basic skeleton, the obtention of highly efficient receptors for ion pairs.

Anion Recognition by Uranyl–Salophen Derivatives as Probed by Infrared Multiple Photon Dissociation Spectroscopy and Ab Initio Modeling

The vibrational features and molecular structures of complexes formed by a series of uranyl-salophen receptors with simple anions, such as Cl(-) , H(-) , and HCOO(-) , have been investigated in the gas phase. Spectra of the anionic complexes were studied in the

Solution and Solid-State Studies on the Halide Binding Affinity of Perfluorophenyl-Armed Uranyl–Salophen Receptors Enhanced by Anion–π Interactions

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Characterization of naproxen-polymer conjugates for drug-delivery.

=800-1800 cm(-1) range by mass-selective infrared multiple photon dissociation (IRMPD) spectroscopy with a continuously tunable free-electron laser. The gas-phase decarboxylation of the formate adducts produces uranyl-salophen monohydride anions, which have been characterized for the first time and reveal a strong UH bond, the nature of which has been elucidated theoretically. The spectra are in excellent agreement with the results obtained from high-quality ab initio calculations, which provided the structure and binding features of the anion-receptor complexes.

Molecular aggregation of novel Zn(II)-salophenpyridyl derivatives

The enhancement of the binding between halide anions and a Lewis acidic uranyl-salophen receptor has been achieved by the introduction of pendant electron-deficient arene units into the receptor skeleton. The association and the occurrence of the elusive anion-π interaction with halide anions (as tetrabutylammonium salts) have been demonstrated in solution and in the solid state, providing unambiguous evidence on the interplay of the concerted interactions responsible for the anion binding.

Ternary assemblies comprising metal–salophen complexes and 4,4′-bipyridine

Abstract The synthesis and the characterization of three new naproxen decorated polymers are described. A versatile and general approach is employed to link the drug to polymers, affording the derivatives with a very high degree of purity. The release of the drug from the conjugates proved to be exceptionally slow, even in acidic aqueous media, and the kinetic of the process seems to be triggered by their solubility in water. On the other hand, the interesting outcome of the first ex vivo drug release experiments on human blood samples makes this preliminary study valuable for future investigations on the use of these polymeric prodrugs in in vivo treatment of inflammatory states.

MicroRNAs delivery into human cells grown on 3D-printed PLA scaffolds coated with a novel fluorescent PAMAM dendrimer for biomedical applications

The synthesis of a series of non-symmetrically substituted zinc(II)-salophenpyridyl [salophenpyridyl = N,N′-2-pyridylenebis-(salicylideneimine)] complexes obtained by reacting RO-substituted salicylaldehydes (R = C10H21 or C16H33) and 2,3-diaminopyridine is here reported. The molecular aggregation behaviour of these derivatives has been thoroughly studied in the solid state. Five new structures have been isolated and analysed. Interestingly, the crystal structure of the complex 2a@4,4′-bipyridine shows the formation of a porous material, whose structure is formed by neutral open boxes potentially able to host guests of suitable dimensions.

Substituent Effects on the Biological Properties of Zn-Salophen Complexes

Two series of ternary assemblies comprising metal–salophen [salophen = N,N′-phenylenebis(salicylideneimine)] complexes (M = Zn2+ or UO22+) and 4,4′-bipyridine have been synthesized. Their absorption and emission data have been compared with those of the corresponding mononuclear derivatives. The dinuclear zinc species present lower emission intensities than those corresponding to the mononuclear precursors, while the emission of the analogous uranyl complexes is observed to increase. Absorption and emission titrations indicate that the ternary species are obtained in two independent coordination steps. The important role of the electron donating/withdrawing properties of the substituents is analyzed regarding their photophysical properties and the association constants. A MLCT transition (recorded by emission spectra) is expected and supported by the increase in the emissive properties of the complexes containing the higher electron donating substituent (methoxy). Nevertheless, this electron donating character disfavors the coordination to bipyridine as shown by the lower calculated association constants. DFT calculations have been performed on the zinc derivatives in order to estimate the relative stability of the dinuclear complexes.

Synthesis and Biological Activity of Gold(I) N-Heterocyclic Carbene Complexes with Long Aliphatic Side Chains

Many advanced synthetic, natural, degradable or non-degradable materials have been employed to create scaffolds for cell culture for biomedical or tissue engineering applications. One of the most versatile material is poly-lactide (PLA), commonly used as 3D printing filament. Manufacturing of multifunctional scaffolds with improved cell growth proliferation and able to deliver oligonucleotides represents an innovative strategy for controlled and localized gene modulation that hold great promise and could increase the number of applications in biomedicine. Here we report for the first time the synthesis of a novel Rhodamine derivative of a poly-amidoamine dendrimer (G = 5) able to transfect cells and to be monitored by confocal microscopy that we also employed to coat a 3D-printed PLA scaffold. The coating do not modify the oligonucleotide binding ability, toxicity or transfection properties of the scaffold that is able to increase cell proliferation and deliver miRNA mimics (i.e., pre-mir-503) into human cells. Although further experiments are required to optimize the dendrimer/miRNA ratio and improve transfection efficiency, we demonstrated the effectiveness of this promising and innovative 3D-printed transfection system to transfer miRNAs into human cells for future biomedical applications.