Pierluca Galloni

Light driven water oxidation by a single site cobalt salophen catalyst

A salophen cobalt(II) complex enables water oxidation at neutral pH in photoactivated sacrificial cycles under visible light, thus confirming the high appeal of earth abundant single site catalysis for artificial photosynthesis.

Tetraferrocenylporphyrins as active components of self-assembled monolayers on gold surface

Novel tetraferrocenylporphyrins-containing self-assembled monolayers were prepared employing two different approaches. Self-assembled monolayers were characterized using UV-Vis spectroscopy and cyclic voltammetry (CV) whereas their photoelectrochemical properties were investigated by photocurrent generation (PG) experiments.

Vanadium-catalyzed, microwave-assisted oxidations with H2O2 in ionic liquids

The application of vanadium(V) catalysts in selective oxidation with peroxides offers an efficient procedure that is compatible with different functional groups and leads to good yields and selectivities. However, the search for more efficient and sustainable procedures that employ H2O2 as oxidant remains an important topic. In the last few years, striking results have been obtained by applying microwave (MW) activation in metal-catalyzed reactions carried out in ionic liquids (ILs). In the present study, results achieved with vanadium-based catalysts in oxidations of various substrates with H2O2 are presented; in particular, epoxidation of alkenes and sulfoxidation of thioethers have been investigated. Notably, in the latter oxidation, a significant improvement in the rate of reaction and an increase in selectivity have been observed in the case of hydrophobic ILs in combination with MW activation.

New developments in chemistry of organometallic porphyrins and their analogs

In this mini-review, new developments in chemistry of organometallic porphyrins and their analogs reported between 2007 and mid 2012 have been discussed. Synthetic strategies for preparation, as well as properties of metallocenyl-type compounds in which organometallic substituents connected to the porphyrinoid via (i) axial coordination; (ii) covalent bond to meso- or β-pyrrolic position; or (iii) β,β′-fused into the aromatic system as well as porphyrinoids with organometallic fragments σ-bonded in η1-fashion were overviewed.

Electronic Properties of Mono‐Substituted Tetraferrocenyl Porphyrins in Solution and on a Gold Surface: Assessment of the Influencing Factors for Photoelectrochemical Applications

Two unsymmetric meso-tetraferrocenyl-containing porphyrins of general formula Fc3 (FcCOR)Por (Fc=ferrocenyl, R=CH3 or (CH2)5 Br, Por=porphyrin) were prepared and characterized by a variety of spectroscopic methods, whereas their redox properties were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) approaches. The mixed-valence [Fc3 (FcCOR)Por](n+) (n=1,3) were investigated using spectroelectrochemical as well as chemical oxidation methods and corroborated with density functional theory (DFT) calculations. Inter-valence charge-transfer (IVCT) transitions in [Fc3 (FcCOR)Por](+) were analyzed, and the resulting data matched closely previously reported complexes and were assigned as Robin-Day class II mixed-valence compounds. Self-assembled monolayers (SAMs) of a thioacetyl derivative (Fc3 (FcCO(CH2)5 SCOCH3 )Por) were also prepared and characterized. Photoelectrochemical properties of SAMs in different electrolyte systems were investigated by electrochemical techniques and photocurrent generation experiments, showing that the choice of electrolyte is critical for efficiency of redox-active SAMs.

Sustainable vanadium(V)-catalyzed oxybromination of styrene: Two-phase system versus ionic liquids

Oxybromination reaction of styrene was performed in a two-phase system of water/ionic liquids (ILs). The aim of the work was to make the mild and efficient two-phase system previously developed for the vanadium(V)-catalyzed oxybromination of alkenes, inspired by the activity of haloperoxidase enzymes, even more interesting from a sustainable point of view. As in that case, a brominating intermediate was formed from the metal catalyst, H2O2, and bromide ion in the acid aqueous phase, but chlorinated solvents were replaced with ILs. [bmim+][PF6-], [bm2im+][PF6-], [bmim+][BF4-], [bmim+][CF3SO3-], and [bmim+][(CF3SO2)2N-] were tested. We report on interesting results in terms of reaction rates and selectivities.

The corrole and ferrocene marriage: 5,10,15-triferrocenylcorrolato Cu.

Two synthetic routes have been defined for the preparation of a 5,10,15-triferrocenylcorrole Cu derivative. This complex has been characterized and the preliminary electrochemical investigation shows a strong interaction among the corrole and meso ferrocenyl substituents. The results obtained suggest that peculiar properties are gained by combining the eccentric characteristics of ferrocenyl substitution with the corrole macrocycle.

The Pt(II)-catalyzed Baeyer–Villiger oxidation of cyclohexanone with H2O2 in ionic liquids

The Pt(II)-catalyzed Baeyer–Villiger oxidation of cyclohexanone with H2O2 in a two-phase system, H2O–IL, is a viable procedure, characterized by synthetically interesting yields, better than those of the same reaction in H2O–halogenated solvents.

A Ferrocene-Porphyrin Ligand for Multi-Transduction Chemical Sensor Development

5,10,15,20-Tetraferrocenyl porphyrin, H2TFcP, a simple example of a donor-acceptor system, was tested as ligand for the development of a novel multi-transduction chemical sensors aimed at the determination of transition metal ions. The fluorescence energy transfer between ferrocene donor and porphyrin acceptor sub-units was considered. The simultaneously measured optical and potentiometric responses of solvent polymeric membranes based on H2TFcP permitted the detection of lead ions in sample solutions, in the concentration range from 2.7 × 10−7 to 3.0 × 10−3 M. The detection limit of lead determination was 0.27 μM, low enough to perform the direct analysis of Pb2+ in natural waters.

A sustainable two-phase procedure for V-catalyzed toluene oxidative bromination with H2O2–KBr

A sustainable V(V) and Mo(VI) catalysed two-phase procedure for bromination of toluene under quite mild conditions is proposed; H2O2 is the primary oxidant and KBr is the bromine source; metal precursors are commercially available salts. The reaction is efficient without any additional solvent. By using PhCH3 as a solvent/substrate good yields, together with interesting selectivity toward the formation of PhCH2Br, are obtained with both metal ions. Recycling of the catalytic phase is also possible. Useful information on the V-peroxido chemistry was obtained.