Advances in Nanomaterials Based on Cashew Nut Shell Liquid.

Cashew nut shell liquid (CNSL), obtained as a byproduct of the cashew industry, represents an important natural source of phenolic compounds, with important environmental benefits due to the large availability and low cost of the unique renewable starting material, that can be used as an alternative to synthetic substances in many industrial applications. The peculiarity of the functional groups of CNSL components, such as phenolic hydroxyl, the aromatic ring, acid functionality, and unsaturation(s) in the C15 alkyl side chain, permitted the design of interesting nanostructures. Cardanol (CA), anacardic acid (AA), and cardol (CD), opportunely isolated from CNSL, served as building blocks for generating an amazing class of nanomaterials with chemical, physical, and morphological properties that can be tuned in view of their applications, particularly focused on their bioactive properties.

Green Aspects in Molecularly Imprinted Polymers by Biomass Waste Utilization.

Molecular Imprinting Polymer (MIP) technology is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. In the last decades, MIP technology has gained much attention from the scientific world as summarized in several reviews with this topic. Furthermore, green synthesis in chemistry is nowadays one of the essential aspects to be taken into consideration in the development of novel products. In accordance with this feature, the MIP community more recently devoted considerable research and development efforts on eco-friendly processes. Among other materials, biomass waste, which is a big environmental problem because most of it is discarded, can represent a potential sustainable alternative source in green synthesis, which can be addressed to the production of high-value carbon-based materials with different applications. This review aims to focus and explore in detail the recent progress in the use of biomass waste for imprinted polymers preparation. Specifically, different types of biomass waste in MIP preparation will be exploited: chitosan, cellulose, activated carbon, carbon dots, cyclodextrins, and waste extracts, describing the approaches used in the synthesis of MIPs combined with biomass waste derivatives.

Heterogenized Pyridine-Substituted Cobalt(II) Phthalocyanine Yields Reduction of CO2 by Tuning the Electron Affinity of the Co Center.

Conversion of CO2 to reduced products is a promising route to alleviate irreversible climate change. Here we report the synthesis of a Co-based phthalocyanine with pyridine moieties (CoPc-Pyr), which is supported on a carbon electrode and shows Faradaic efficiency ∼90% for CO at 490 mV of overpotential (-0.6 V vs reversible hydrogen electrode (RHE)). In addition, its catalytic activity at -0.7 V versus RHE surpasses other Co-based molecular and metal-organic framework catalysts for CO2 reduction at this bias. Density functional theory calculations show that pyridine moieties enhance CO2 adsorption and electron affinity of the Co center by an inductive effect, thus lowering the overpotential necessary for CO2 conversion. Our study shows that CoPc-Pyr reduces CO2 at lower overpotential and with higher activity than noble metal electrodes, such as silver.

Nanomaterials Based on Fe3O4 and Phthalocyanines Derived from Cashew Nut Shell Liquid.

In this work we report the synthesis of new hybrid nanomaterials in the core/shell/shell morphology, consisting of a magnetite core (Fe3O4) and two consecutive layers of oleic acid (OA) and phthalocyanine molecules, the latter derived from cashew nut shell liquid (CNSL). The synthesis of Fe3O4 nanoparticle was performed via co-precipitation procedure, followed by the nanoparticle coating with OA by hydrothermal method. The phthalocyanines anchorage on the Fe3O4/OA core/shell nanomaterial was performed by facile and effective sonication method. The as obtained Fe3O4/OA/phthalocyanine hybrids were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, UV-visible spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis and magnetic measurements. TEM showed round-shaped nanomaterials with sizes in the range of 12-15 nm. Nanomaterials presented saturation magnetization (Ms) in the 1-16 emu/g and superparamagnetic behavior. Furthermore, it was observed that the thermal stability of the samples was directly affected by the insertion of different transition metals in the ring cavity of the phthalocyanine molecule.

A green method for the production of an efficient bioimaging nanotool.

The possibility of exploring basic biological phenomena requires the development of new and efficient bio-imaging tools. These should ideally combine the feasibility of production (potentially through the use of green chemistry) together with high targeting efficiency, low cytotoxicity, and optimal contrast characteristics. In this work, we developed nanovesicles based on cardanol, a natural and renewable byproduct of the cashew industry, and a fluorescent reporter was encapsulated in them through an environment-friendly synthesis method. In vitro investigations demonstrated that the cardanol nanovesicles are efficiently taken-up by both professional and non-professional phagocytic cells, which have been modeled in our approach by macrophages and HeLa cells, respectively. Co-localization studies show high affinity of the nanovesicles towards the cell plasma membrane. Moreover, metabolic assays confirmed that these nanostructures are biocompatible in a specific concentration range, and do not promote inflammation response in human macrophages. Stability studies carried out at different temperatures showed that the nanovesicles are stable at both 37 °C and 20 °C, while the formation of aggregates occurs when the nanodispersion is incubated at 4 °C. The results demonstrate the high potential of fluorescent cardanol nanovesicles as a green bioimaging tool, especially for investigating cell membrane dynamics.

First example of a lipophilic porphyrin-cardanol hybrid embedded in a cardanol-based micellar nanodispersion.

Cardanol is a natural and renewable organic raw material obtained as the major chemical component by vacuum distillation of cashew nut shell liquid. In this work a new sustainable procedure for producing cardanol-based micellar nanodispersions having an embedded lipophilic porphyrin itself peripherally functionalized with cardanol substituents (porphyrin-cardanol hybrid) has been described for the first time. In particular, cardanol acts as the solvent of the cardanol hybrid porphyrin and cholesterol as well as being the main component of the nanodispersions. In this way a "green" micellar nanodispersion, in which a high percentage of the micellar system is derived from renewable "functional" molecules, has been produced.

Novel lipophilic lanthanide bis-phthalocyanines functionalized by pentadecylphenoxy groups: synthesis, characterization and UV-photostability.

Novel sandwich-type phthalocyanines containing a rare earth metal core (Pr, Nd, Eu-Lu) and macrocycles peripherally substituted by pentadecylphenoxy groups were synthesized using a cardanol-based phthalonitrile precursor and the respective lanthanide acetate. Additionally, the metal free-base analog compound was studied for comparison. The purified reaction products were all found to be thick and viscous substances at room temperature, showing liquid crystalline behavior with a distinct increase in fluidity at ca. 40 ° C. The complexes are readily soluble in chloroalkyl solvents and dissolve fairly well in DMF with some tendency to form aggregates. Besides they are strongly hydrophobic and reveal a peculiar affinity for lipophilic media. The compounds have been characterized by UV-Vis (absorption and emission), FTIR, MS and DSC methods. Photochemical activity in the liquid phase (dimethylformamide, dichloromethane, mineral oil) and the degree of photodegradation demonstrated under constant UV-irradiation (λ = 352 nm) have been analyzed and discussed in terms of photostability.

Design and synthesis of cellulose derivatives with antioxidant activity.

In this study we report the synthesis and characterisation of cellulose ferulate, lipoate and alpha-tocopherulate, and their ability to inhibit lipid peroxidation in rat-liver microsomal membranes, induced in vitro by two different sources of free radicals: tert-butyl hydroperoxide and 2,2'-azobis-(2-amidinopropane). We also compared the antioxidant efficiency of the ferulate derivatives obtained through two different synthetic runs, and of a tocopherulate derivative prepared from 6-carboxycellulose. This study showed that the designed systems, preserving the antioxidant activity of the free substrates, are more effective in protecting from tert-butyl hydroperoxide than from 2,2'-azobis-(2-amidinopropane). Moreover, the cellulose ferulate with the higher degree of substitution acted as the best antioxidant.

New broom fiber (Spartium junceum L.) derivatives: preparation and characterization.

In the past decade interest in biopolymers has increased. Attempts were made to prepare new composite systems from biopolymers by binding different synthetic polymers to a biopolymer backbone. This paper reports the synthesis and characterization of derivatized broom fibers to prepare composites with either degradability or fireproofing properties. Synthetic strategies are described for the introduction of polymerizable functional groups or fluorine atoms on the glucose of cellulose chains of broom. The fibers containing polymerizable groups were copolymerized with dimethylacrylamide and styrene and, after that, investigated by optical polarizing microscopy (OPM) and scanning electron microscopy analysis (SEM). The materials containing fluorine were submitted to thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for the purpose of verifying the fireproofing. Such derivatized biomaterials could be successfully used for applications in agriculture and in the packaging area.