Abstract
The electronic properties of supramolecular materials, such as charge transfer and separation efficiency, depend upon the molecular arrangement of the single components and their mutual interactions. These features determine the effectiveness of crucial properties of the final material such as electroluminescence and photoconversion. A crucial point, however, is how to rationally control the molecular structure in order to attain powerful electronic communication at different length scales from the molecule to the material. Molecular constituents, in fact, generally interact only weakly and randomly, and, moreover, the final molecular arrangement is difficult to predict when molecular components with different characteristics are mixed together. EMBRACE aims at controlling the structural arrangement of molecular components with distinct electronic properties for the formation of P-N heterojunctions in the aggregate state. The main goal of EMBRACE is the application of the design principles to the development of nanostructured materials with improved and tailored electronic communication properties. To achieve these results EMBRACE exploits the principles of molecular recognition to enforce social self-assembly of donor- (D) and acceptor-type (A) π-systems at different length scales, from molecular to bulk. We envision that the preorganization of the opposite type semiconductors in dyads in solution will provide new (nano)materials with unprecedented control over the final morphologies and will give access to the rational design of novel supramolecular architectures. In turns, we expect that this will impact the efficiency of formation of a charge-transfer state (CTS) and the performances of charge separation at the interface.
Results achieved
The first achievement of the project was the design and successful synthesis of donor (D) and acceptor (A) π-conjugated molecular components, suitable for charge- and/or energy-transfer, equipped with complementary recognition motifs. A multistep synthetic protocol was developed compatible with the different functional groups of the molecular structures. The selection of acceptor and donor molecules was based on size similarity to favour host-guest interactions and suitable absorption/emission properties to enable energy and charge transfer. The main outcome was establishing a solid and versatile synthetic procedure potentially applicable to a wide library of donor (D) and acceptor (A) molecular partners and recognition motifs. The two following achievements are (i) the identification of suitable conditions for the self-assembly of the molecular components and (ii) the characterization of the dynamic character of the supramolecular heterocomplexes prior and after interlocking using light. A combination of advanced magnetic resonance (NMR) and mass spectrometry techniques were utilized to identify the nature of the self-assembled species at different concentrations in dark or after irradiation. The outcome was the definition of precise experimental protocols in terms of solvent mixtures, relative concentrations and light-induced locking of the molecular D and A partners to control the morphology of the supramolecular structures. A fourth achievement is the characterization of the energy/electronic communication between the D/A π-conjugated molecular components within the prototype supramolecular system, both in solution and in the aggregated state. By a combination of sophisticated spectroscopic and electrochemical methods we were able to identify the nature and the direction of photoinduced energy/electron transfer process and its relationship with the state of the supramolecular structure involved. The extensive body of data and developed knowledge constitute the basis of (at least) one publication that is currently in preparation by the members of the consortium and will ensure a broad and international resonance of this research within the scientific community.Dettagli del progetto
Responsabile scientifico: Stefano Corrà
Strutture Unibo coinvolte:
Dipartimento di Chimica Industriale "Toso Montanari"
Coordinatore:
CNR - Consiglio Nazionale delle Ricerche(Italy)
Contributo totale Unibo: Euro (EUR) 87.799,00
Durata del progetto in mesi: 24
Data di inizio
16/10/2023
Data di fine:
28/02/2026
