Nanosponge-C3N4 composites with improved photocatalytic activity for selective partial alcohol oxidation in aqueous suspension

Composites of C3N4 with nanosponges based on β-cyclodextrins containing a 5% w/w of C3N4 were synthesised, physicochemicaly characterised and tested as heterogeneous photocatalysts for the degradation of 4-nitrophenol and for the partial oxidation of 5-hydroxymethyl-2-furfural and veratryl alcohol. The results outline a synergistic effect in terms of conversion and selectivity. The association of the nanosponges with the C3N4 enhances the photocatalytic activity of the semiconductor, possibly due to the local concentration effect occurring on the photocatalyst surface that would involve a concentration into the nanosponge matrix ca. 500 times larger than in the solution bulk. Composites of …

Dual drug-loaded halloysite hybrid-based glycocluster for sustained release of hydrophobic molecules

A dual drug-loaded HNT–CD glycocluster delivery system based on halloysite nanotubes and carbohydrate functionalized cyclodextrin was developed by a green protocol using solvent-free microwave irradiation. The nanohybrid was employed for concurrent load and release of silibinin and curcumin. The new delivery system was characterized by means of TGA, FT-IR spectroscopy, SEM and DLS. These techniques confirm the successful loading of the two drugs in the system. SEM and DLS measurements highlighted that the nanomaterial preserves a tubular structure with an average hydrodynamic radius of ca. 200 nm. The release of the drugs from the HNT glycocluster was investigated by means of UV-vis spectro…

Chemical and pharmaceutical evaluation of the relationship between triazole linkers and pore size on cyclodextrin–calixarene nanosponges used as carriers for natural drugs

Mixed cyclodextrin–calixarene nanosponges were used to prepare some composites with the well known polyphenolic bioactive compounds quercetin and silibinin. The composites were characterized by means of different techniques (UV-vis, FT-IR, microcalorimetry, thermogravimetry), in order to assess their loading and thermal stability. The kinetics of release of the bioactive molecules into aqueous solution were studied at two different pH values (1.0, 6.4), which mimic typical physiological conditions. Finally the possible antiproliferative effects in vitro were assayed towards three triple negative breast cancer cell lines (SUM 149, SUM 159 and MDA-MB-23). Our results point out the role assume…

Lipase-catalyzed resolution of anti-substituted 1,3-dioxepan-5-ols

Several anti-6-substituted 1,3-dioxepan-5-ols were kinetically resolved using an immobilized lipase (Amano PS–C II) in toluene in the presence of vinyl acetate at 30 C. This approach provided, in some cases, the alcohol and the acetate in high enantiomeric purity, depending on the nature of the substituent (R = N3, SePh, I, OBn) and the acetal group (unsubstituted or dimethyl). The role of the size of substituents is also discussed. Enantiopure anti-6-substituted 1,3-dioxepan-5-ols are useful building blocks.

Oxidative degradation properties of Co-based catalysts in the presence of ozone

Four series of cobalt-based catalysts, such as bare Co3O4 and CoO, CoOx-CeO2 mixed oxides, CoOx supported over alumina and alumina-baria and CoMgAl and CoNiAl hydrotalcites have been synthesized and investigated for the oxidative degradation of phenol in the presence of ozone. Characterizations were obtained by several techniques in order to investigate the nature of cobalt species and their morphological properties, depending on the system. Analyses by XRD, BET, TPR, UV-visible diffuse reflectance spectroscopy and TG/DT were performed. The CoNiAl hydrotalcite exhibits, after 4 h of reaction, the highest phenol ozonation activity followed by Co(3 wt%)/Al2O3-BaO and CoMgAl. The samples Co(1 …

C3N4/reduced graphene oxide photocatalysts loaded with Ag or Ag/Pt for H2 evolution from aqueous solution of triethanolamine

Composites of C3N4/reduced graphene oxide have been used as photocatalysts for triethanolamine photo- reforming with H2 generation in aqueous solution. The rate of H2 production over the Ag loaded best per- forming photocatalyst reached 525 μmol⋅h

Studies On Rosmarinic Acid And Its Derivatives

An automatic L1-based regularization method for the analysis of FFC dispersion profiles with quadrupolar peaks

Fast Field-Cycling Nuclear Magnetic Resonance relaxometry is a non-destructive technique to investigate molecular dynamics and structure of systems having a wide range of ap- plications such as environment, biology, and food. Besides a considerable amount of liter- ature about modeling and application of such technique in specific areas, an algorithmic approach to the related parameter identification problem is still lacking. We believe that a robust algorithmic approach will allow a unified treatment of different samples in several application areas. In this paper, we model the parameters identification problem as a con- strained L 1 -regularized non-linear least squares problem. Following…

Functionalized halloysite multivalent glycocluster as a new drug delivery system.

A new design for halloysite nanotube materials was obtained by grafting chemically modified cyclodextrin units onto the nanotube surface. In particular, grafted cyclodextrins were decorated with thiosaccharide pendants, in order to mimic the well-known binding of sugars to proteins and the glyco-cluster effect occurring during cellular recognition events. The obtained materials were characterized by using a combination of varied techniques (FT-IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, dynamic light scattering, turbidimetry), and their potential drug-delivery abilities were tested by studying their interactions with the common naturally occurring anticancer a…

Cyclodextrin-based nano-devices for improved antibiotic activity

FFC-NMR Relaxometric Characterization of Nanosponges for Rationalizing their Adsorption and Release abilities

Scopolamine Derivatives as Potential Pharmaceuticals with Calixarene-CyclodextrineNanosponges as Drug Carriers

Tropane alkaloids are molecules with a strong biological activity, which are mainly produced by the members offamily Solanaceae, but also found inother plant families (Convolvulaceae, Brasicaceae, Erythroxylaceae andEuphorbiaceae).1 More than 20 active pharmaceutical substances containingthetropane moiety have been industrially produced and applied as mydriatics, antiemetics, antispasmodics, anesthetics and bronchodilators.Nearly all of them are based on the Scopolamine structure.2 In recent years, several researchers aimed their work to the use of supramolecular systems for the inclusion of organic species, such as complex systems based on cyclodextrines or calixarenes.3They have attracted…