Fluorinated Materials: Reactivity, Self-Organization and Functions

Research focus

The Peer review has evaluated this group as Excellent

The research focus of this group is in the identification and exploitation of the potential of fluorinated derivatives. The unifying theme is the unique chemical behaviour of fluoroorganics both at the molecular and supramolecular levels. The full understanding of this behaviour is the prerequisite for the design and engineering of the applicative useful properties of these compounds. A particular attention is devoted to the self-organization and self-assembly of fluorocarbons. Fluorine atom has quite peculiar characteristics, which are responsible for the unique and useful properties that the presence of this halogen imparts to any compound and material. The impact of fluorine spans many technologically intensive fields, from the area of drugs and pharmaceuticals, to polymer chemistry and materials for refrigeration or coating. The interests of this group are both on selectively fluorinated and perfluorinated derivatives and the fallouts are in material sciences and drug design. Fluorinated compounds present a very specific REACtivity (acronym REAC) and the group has a deep and diversified expertise in the preparation and transformation of fluoroorganics. Pure F2 gas is available and is used, among others, to prepare some strategically useful intermediates in polymer chemistry (e.g. perfluoroalkyl hypofluorites). The reactivity of many fluorinated derivatives frequently occurs through a radical process, which is also actively studied in the group. In this field, the focus is on new free radical reactions from both mechanistic and synthetic points of view. The general problem of selective perfluoroalkylation is addressed by using perfluoroalkyl iodides and perfluoroperoxides; the stability/interaction of these compounds when challenged by persistent radicals is also under study. The judicious introduction of a single fluorine atom or appropriate fluorinated functionalities into a target molecule has become a first choice method to modify and tune biological properties in bioorganic and medicinal chemistry. In this context, this group has developed new stereocontrolled and combinatorial protocols, both in solution and in solid-phase, for the synthesis of many fluoroalkyl peptidomimetics. A particular field of interest is a powerful strategy for replacing the peptide bond with a very effective and hydrolytically stable mimic, the trifluoroethylamine function. Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta” – Research Assessment Excercise 2003-2006 68 This approach has recently found validation in highly active drugs (Angew. Chem. Int. Ed. 2003, 42, 2060). In the design and synthesis of the fluorocarbon derivatives described above, a particular attention is paid to their environmental impact, a key issue for fluorochemicals. The general concept is the search for fluorochemicals that maintain or even improve the performances of presently used compounds, but present a better profile from the sustainability point of view. Perfluorinated derivatives are endowed with unique phase behaviour as they have a low affinity for both polar and non polar substances, this behaviour being responsible for their usefulness as selfcleaning, water and oil repellent coatings. The nanostructure of these coatings and their adhesion to (namely affinity for) the supporting layers are of fundamental importance. The group has a strong focus on the fundamental relationships between the structures of perfluorocarbons and the peculiar profiles of their phase properties. The group identified a general approach for driving the Self-ORGanization (acronym SORG) of perfluorocarbons with hydrocarbons and organic or inorganic salts. Two components (hydrocarbon/perfluorocarbon) and three-component (perfluorocarbon/hydrocarbon/organicinorganic salt) hybrid materials have been prepared and their structure investigated. The topological properties of the obtained systems are of key relevance for the functional properties they possess. The topological issue in the prepared hybrid material is investigated in detail. Unprecedented topologies have been obtained as it is the case for highly interpenetrated three dimensional architectures. A unique ability of the group is in the crystallographic analysis of perfluorocarbons, a class of compounds that is notoriously affected by high disorder at a molecular level. This ability allows fundamental problems in perfluorocarbons chemistry to be addressed, e.g. perfluorocarbons’ conformational preferences (Angew. Chem. Int. Ed. 2006, 45, 19159). There is the problem to identify the molecular characteristics and parameters that allow to design and engineer crystal structures. This problem is faced by using several other analytical techniques so that some heuristic principles have been developed, which are allowing the group to design hybrid systems with pre-established FUNCtions (acronym FUNC). This was the case for a templated approach to solid state synthesis (J. Am. Chem. Soc. 2004, 126, 4500), for a ditopic receptor for metal halides (J. Am. Chem. Soc. 2005, 127, 14972), for self-assembled liquid crystals (Chem. Commun. 2006, 3290). Fluorous coatings are also under active study via covalent and noncovalent approaches. Substrates under investigations are organic polymers (e.g. channels in microfluidic devices), carbon nanotubes, diamond-like carbon, and graphite.

Departments

Dipartimento di Chimica, Materiali e Ingegneria Chimica

Professors

Full Professors
Giuseppe Resnati
Associate Professors
Luca Bruchè
Pierangelo Metrangolo
Walter Navarrini
Calimero Ticozzi
Assistant Professors
Francesco Recupero
Alessandro Volonterio