Efficient electron delocalization mediated by aromatic homoconjugation in 7,7-diphenylnorbornane derivatives.
Efficient electron delocalization by aromatic homoconjugated 7,7-diphenylnorbornane (DPN) in alternated homoconjugated-conjugated block copolymers and reference compounds is revealed by photophysical and electrochemical measurements. The synthesis of the polymers was achieved by Suzuki polycondensation reaction. Effective electron delocalization by DPN is demonstrated by the significant red shifts observed in the absorption and emission spectra and the variation of the energy band gap of the polymers and monomeric model compounds in comparison to a series of oligophenylenes used as references (p-quaterphenyl, p-terphenyl, and biphenyl). The electron delocalization is also clearly demonstrated by the lower oxidation potential measured for homoconjugated model compound in comparison to p-terphenyl. The results show that the electron delocalization caused by two homoconjugated aryl rings is comparable to the effect produced by one conjugated aryl ring.
Osío Barcina
José
J
Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain. josio@quim.ucm.es
Colorado Heras
María del Rosario
Mdel R
Mba
Miriam
M
Gómez Aspe
Rafael
R
Herrero-García
Noelia
N