title: Synthesis, photophysical, electrochemical, and electrochemiluminescent properties of 5,15-bis(9-anthracenyl)porphyrin derivatives.
abstract: Novel 5,15-bis(9-anthracenyl)porphyrin derivatives (, ) were synthesized by stepwise Suzuki-type coupling reactions using anthracenyl-boronates bearing various electronically active moieties. Absorption spectra of these porphyrin conjugates reveal some degree of delocalisation with the directly linked chromophores, particularly in the case of anthracenyl-porphyrin bearing dimethylanilino moieties at the two extremities. Fluorescence and 77 K phosphorescence properties indicate that the excitation energy is invariably funnelled to the lowest singlet and triplet states of the porphyrin chromophore. The latter levels have been probed also by transient absorption spectroscopy, showing the typical triplet features detected in meso-substituted porphyrins. Extensive electrochemical studies have been performed to unravel the electronic properties of the newly synthesized porphyrins. Low-temperature cyclic voltammetry investigations showed that the anthracenyl-porphyrins are capable of undergoing as many as four electron transfer processes. In particular, by means of UV-Vis-NIR spectroelectrochemical measurements, a NIR-centred intramolecular photoinduced intervalence charge transfer (IV-CT) from a neutral N,N-dimethylanilino moiety to the N,N-dimethylanilino radical cation has been observed for the doubly-oxidised porphyrin (2+). The molecules also showed unexpected electrogenerated chemiluminescence properties, which revealed to be largely controlled by the electronic characteristics of the peripheral anthracenyl substituents. The structural and the electronic properties of these complexes have been also characterised by DFT calculations, as well as by X-ray crystallographic analyses.
authors.affiliation: Università degli Studi di Trieste, Dipartimento di Scienze Farmaceutiche and INSTM UdR Trieste, Trieste, Italy.
authors.forename: Chloè
authors.initials: C
authors.lastname: Sooambar
authors.forename: Vincent
authors.initials: V
authors.lastname: Troiani
authors.forename: Carlo
authors.initials: C
authors.lastname: Bruno
authors.forename: Massimo
authors.initials: M
authors.lastname: Marcaccio
authors.forename: Francesco
authors.initials: F
authors.lastname: Paolucci
authors.forename: Andrea
authors.initials: A
authors.lastname: Listorti
authors.forename: Abdelhalim
authors.initials: A
authors.lastname: Belbakra
authors.forename: Nicola
authors.initials: N
authors.lastname: Armaroli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Magistrato
authors.forename: Rita
authors.initials: R
authors.lastname: De Zorzi
authors.forename: Silvano
authors.initials: S
authors.lastname: Geremia
authors.forename: Davide
authors.initials: D
authors.lastname: Bonifazi
mesh_terms: D000873:Anthracenes / Q000138:chemical synthesis / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D049449:Luminescence; D008958:Models, Molecular; D015394:Molecular Structure; D055668:Photochemical Processes; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D013053:Spectrophotometry
chemical_list: D000873:Anthracenes; D011166:Porphyrins