Albert Ruggi

Heptacoordinate CoII Complex: A New Architecture for Photochemical Hydrogen Production

The first heptacoordinate cobalt catalyst for light-driven hydrogen production in water has been synthesized and characterized. Photochemical experiments using [Ru(bpy)3 ]2+ as photosensitizer gave a turnover number (TON) of 16300 mol H2  (mol cat.)-1 achieved in 2 hours of irradiation with visible (475 nm) light. This promising result provides a path forward in the development of new structures to improve the efficiency of the catalysis.

Synthesis of hydrophilic and hydrophobic carbon quantum dots from waste of wine fermentation

Wine lees are one of the main residues formed in vast quantities during the fermentation of wine. While toxic when applied to plants and wetlands, it is a biodegradable material, and several alternatives have been proposed for its valorization as: dietary supplement in animal feed, source for various yeast extracts and bioconversion feedstock. The implementation of stricter environment protection regulations resulted in increasing costs for wineries as their treatment process constitutes an unavoidable and expensive step in wine production. We propose here an alternative method to reduce waste and add value to wine production by exploiting this rich carbon source and use it as a raw material for producing carbon quantum dots (CQDs). A complete synthetic pathway is discussed, comprising the carbonization of the starting material, the screening of the most suitable solvent for the extraction of CQDs from the carbonized mass and their hydrophobic or hydrophilic functionalization. CQDs synthesized with the reported procedure show a bright blue emission (λmax = 433 ± 13 nm) when irradiated at 366 nm, which is strongly shifted when the wavelength is increased (e.g. emission at around 515 nm when excited at 460 nm). Yields and luminescent properties of CQDs, obtained with two different methods, namely microwave and ultrasound-based extraction, are discussed and compared. This study shows how easy a residue can be converted into an added-value material, thus not only reducing waste and saving costs for the wine-manufacturing industry but also providing a reliable, affordable and sustainable source for valuable materials.

Heptacoordinate Co(II) Catalyst for Light-driven Hydrogen Production in Fully Aqueous Medium

Photocatalytic hydrogen production is an appealing way to store solar energy as chemical fuel. The most studied molecular catalysts for H2 production are based on earth-abundant metals such as Ni, Co and Fe. Efforts have been recently focused on the design of Co complexes with distorted octahedral geometries induced by tetra- or pentapyridyl ligands. We synthesized a new Co(II) complex based on a hexapyridyl ligand that leads to the formation of an unusual heptacoordinate structure. In this paper, we review the characterization of the new catalyst and the optimization of the conditions for hydrogen evolution. The high activity reached after two hours of irradiation under visible light (475 nm) suggests that heptacoordinate cobalt complexes, not used so far in the field of light-driven hydrogen evolution, represent a promising alternative platform for the development of highly active and stable photocatalysts.

Lab-on-glass system for DNA treatments

This paper presents the fabrication and testing of a lab-on-chip system suitable for treatment of DNA. It includes two main modules: a system-on-glass (SoG) and a disposable microfuidic chip. The SoG integrates, on the same glass substrate, thin film metal heaters and amorphous silicon temperature sensors to achieve a uniform temperature distribution (within ±1°C) in the heated area. Two polydimethylsiloxane microfluidic chips have been developed: a PCR-Chip for DNA amplification and a dsDNA-Chip for separation and selective isolation of a ssDNA from a dsDNA. The proposed system aims therefore to develop compact, low-cost devices that can implement multiple functions in biochemical procedures. In particular, the tested bioanalytical procedures are well suited for carrying-out an on-chip SELEX process, a combinatorial chemistry technique for the selection of aptamers.