Laboratory

Research

Porphyrins, the pigments of life

Porphyrins are ubiquitous in Nature and, in association with different metals, play a key role in many different aspects of life. As very stable and incredibly versatile molecules, porphyrins may be exploited for many different goals.

Chemosensors

More recently research has also moved towards the synthesis of metal porphyrin complexes to use them as high selective chemosensors for analysing the presence of emerging pollutants in water and air (such as diclofenac and formaldehyde, respectively) as well as of food contaminants (such as trichloroanisole, in “corked” wine). The chemical versatility of metal porphyrins allows several skeleton modifications and the introduction of a large class of transition metals into the porphyrin core. This synthetic approach permits modulation of the porphyrin structure with respect to the target analyte as well as fine-tuning the analyte/chemosensor interaction. In addition, the spectroscopic, photophysical and redox features of porphyrins and metal porphyrins allow the exploitation of different transduction mechanisms by the same sensing porphyrin materials, thus extending and increasing their sensing performance.

Catalysis

Synthesis of fine chemicals: the research activity is mainly devoted to the eco-compatible synthesis of fine chemicals by new C-C and C-N bond formations. Organic azides (ArN3) and diazo-compounds (RR’CN2) are employed as atom efficient reagents to transfer nitrene and carbene functionalities to saturated and unsaturated hydrocarbons, respectively. These synthetic procedures are responsible for the synthesis of aziridines, allylic amines, benzylic amines, imines, phenanthridines, indoles and cyclopropane-containing molecules. The scientific significance of these synthetic methodologies is due to: a) their high atomic efficiency and eco-sustainability (N2 is the only by-product of the transfer reaction), and b) the method allows the transformation of low-cost compounds, such as hydrocarbons, into high-added value derivatives, which often exhibit biological and/or pharmaceutical properties. In addition, the transformation of highly “energetic” aziridines into fine-chemicals of a pharmaceutical interest, such as benzoazepines, has also been explored. These synthetic transformations are efficiently catalysed by low-toxic metal porphyrin complexes, which show “green” transition metals of the first row as active catalytic centres. The chemo-physical behaviour of porphyrin catalysts can be easily fine-tuned by introducing eco-compatible functional groups such as amino acids and carbohydrates. In order to optimise synthetic strategies, catalytic mechanisms are investigated by identifying catalytic intermediates and performing kinetic and DFT studies. Cyclopropanes were also obtained with good enantio- and diastereoselectivities by employing chiral metal porphyrins as asymmetric catalysts.
CO2 valorisation: In order to contribute to the transition from linear to circular chemical processes, we are currently working on new synthetic routes, which employ CO2 as a C1 renewable raw material to produce high added-value fine-chemicals, such as cyclic carbonates and oxazolidinones, which address different end-use customers. Besides the production of largely-used cyclic carbonate solvents (such as 1,2-butylene carbonate), the synthesis of oxazolidinones, which are precursors of pharmaceutical species (e.g. the medicinal activity of 5-(4-florophenyl)-3-(3-methoxyphenyl)-1,3-oxazalidin-2-one has been already demonstrated), has also been investigated. These transformations are efficiently promoted by low-cost and low-toxic porphyrin-based catalytic systems.

Heterogenization

Metal porphyrin complexes can also be embedded in polymeric membranes to synthesise fine chemicals by using the continuous flow processing technology. The heterogenisation of homogeneous catalysts offers the advantages of both homogeneous and heterogeneous catalysis. In fact, benefits of a ‘single site’ catalysis are coupled with an easy recovery and recycling of the catalyst. Cyclopropanation reactions are also promoted by polyoxometalates (POMs) which are often presented as inorganic analogous of metalloporphyrins and show high chemical stability and synthetic potential. The syntheses of polyoxometalates allow structural modifications of their skeleton and the coordination of one or more catalytically active transition metals.

Scientific Collaborations

Prof. Maurizio Benaglia, Prof. Alessandra Puglisi (University of Milan, Italy)
Dr. Bernard Boitrel (CNRS, Université de Rennes 1, France)
Prof. Alessandro Caselli (University of Milan, Italy)
Prof. Corrado Di Natale (University of Rome “Tor Vergata”, Italy)
Prof. Luigi Lay (University of Milan, Italy)
Dr. Carlo Mealli, Dr. Gabriele Manca (ICCOM-CNR, Florence, Italy)
Prof. Roberto Paolesse (University of Rome “Tor Vergata”, Italy)
Prof. Anna Proust (Sorbonne University, France)
Prof. Fabio Ragaini (University of Milan, Italy)
Prof. Lucio Toma (Univeristy of Pavia, Italy)

             Research Developing

IMAG0502
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