1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) imprinted polymer was prepared as microspheres by precipitation polymerization method to obtain molecular recognition systems based on the noncovalent interactions between DBU template, methacrylic acid (MAA), and ethylene .glycol dimethacrylate (EDMA) in acetonitrile. 1 H NMR analysis of DBU/ MAA mixture has been performed and hydrogen bonding interactions have been established. Microspheres have been characterized by FTIR studies with evidence of DBU linkage in polymer particles and by Scanning Electron Microscopy (SEM) to study their morphological properties. How pH values affect the binding capacity of imprinted polymer during the binding stage has been also discussed and results suggest that imprinted poly-(MAA-EDMA) behavior is related to the influence of DBU basicity during rebinding processes and the optimum pH value for binding has been found around neu-tral range. Binding ability of the imprinted polymer towards different concentration of DBU buffered solutions has been evaluated and compared with binding ability of the nonimprinted polymer. A more sensitive response to the template in the imprinted system suggests that a reasonable number of specific binding sites is formed. Finally, differential selectivity towards other less strong than DBU nitrogen bases, such as pyridine, imidazole, and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) has been also discussed. Our results indicate that both specific sites and basic properties are involved in the rebinding process.

Novel Zn (II) phthalocyanine and naphthalocyanine DBU complexes have been prepared in a one-pot synthesis reacting phthalonitrile precursors with an excess of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). For the first time, it has been well evidenced that DBU played the role of coordinating axial ligand together with the well known role of strong base. Also, DBU complexes showed better solubility in organic solvents due to the coordination of the bulky axial DBU ligand, compared to the Zn (II) phthalocyanines and naphthalocyanines without coordinated DBU. The coordinating properties of DBU toward ZnPcs (DBU free) complexes have also been investigated along with the ZnPc (pyridine) complex. Thermal analysis results reflecting the stability of the synthesized complexes under air are also presented.

Spectral studies and job plot analyses which provide evidence of the formation of complexes of zinc phthalocyanines or zinc naphthalocyanines and nicotinamide or its positional isomers, known as isonicotinamide and picolinamide, are reported. Nicotinamide, isonicotinamide and picolinamide contain the amide group in a different position in the ring and these molecules can coordinate the metal of phthalocyanines through their nitrogen pyridinic atom, or their amide group, to form complexes. FT-IR and NMR spectroscopic studies, as well as job plot analyses in chloroform, have been performed. To validate the formation of complexes, some of them have been isolated, fully characterized and their binding properties and thermal stability have also been investigated.

Among all the inorganic nanomaterials used in commercial products, industry, and medicine, the amorphous silica nanoparticles (SiO2 NPs) appeared to be often tolerated in living organisms. However, despite several toxicity studies, some concerns about the exposure to high doses of SiO2 NPs with different sizes were raised. Then, we used the microemulsion method to obtain stable SiO2 NPs having different sizes (110 nm, 50 nm, and 25 nm). In addition, a new one-pot green synthetic route using leaves extract of Laurus nobilis was performed, obtaining monodispersed ultrasmall SiO2 NPs without the use of dangerous chemicals. The NPs achieved by microemulsion were further functionalized with amino groups making the NPs surface positively charged. Then, high doses of SiO2 NPs (1 mg/mL and 3 mg/mL) achieved from the two routes, having different sizes and surface charges, were used to assess their impact on human alveolar cells (A549), being the best cell model mimicking the inhalation route. Cell viability and caspase-3 induction were analyzed as well as the cellular uptake, obtaining that the smallest (25 nm) and positive-charged NPs were more able to induce cytotoxicity, reaching values of about 60% of cell death. Surprisingly, cells incubated with green SiO2 NPs did not show strong toxicity, and 70% of them remained vital. This result was unusual for ultrasmall nanoobjects, generally highly toxic. The actin reorganization, nuclear morphology alteration, and cell membrane elasticity analyses confirmed the trend achieved from the biological assays. The obtained data demonstrate that the increase in cellular softness, i.e., the decrease in Young’s modulus, could be associated with the smaller and positive NPs, recording values of about 3 kPa. On the contrary, green NPs triggered a slight decrease of stiffness values (c.a. 6 kPa) compared to the untreated cells (c.a. 8 kPa). As the softer cells were implicated in cancer progression and metastasization, this evidence strongly supported the idea of a link between the cell elasticity and physicochemical properties of NPs that, in turn, influenced the interaction with the cell membrane. Thus, the green SiO2 NPs compromised cells to a lesser extent than the other SiO2 NPs types. In this scenario, the elasticity evaluation could be an interesting tool to understand the toxicity of NPs with the aim of predicting some pathological phenomena associated with their exposure.