Investigations on the electronic effects of the peripheral 4'-group on 5-(4'-substituted)phenylazo-8-hydroxyquinoline ligands: zinc and aluminium complexes.
A new series of 5-(4'-substituted)phenylazo-8-hydroxyquinolines (H[L-R]; R = N(CH(3))(2), C(2)H(5), n-C(4)H(9), C(CH(3))(3), H, and F, ) has been prepared and the corresponding Zn[L-R](2) (1a-6a) and Al[L-R](3) (1b-6b) complexes successfully synthesized. These compounds have been studied in order to design new molecular materials with enhanced electron transport properties. The obtained species have been extensively characterized by absorption and emission spectra and by cyclic voltammetric measurements. Experimental and computational results show that the Zn[L-N(CH(3))(2)].2H(2)O (1a) and Al[L-N(CH(3))(2)](1b) complexes only feature luminescence (at 620 and 600 nm), respectively. The unique effects, which are induced by the N=N-C(6)H(4)-N(CH(3))(2) group, are further proved by a reversible electron transfer process detected by cyclic voltammetry. These outcomes, discussed on the basis of theoretical calculations performed on the (H[L-N(CH3)2])-, H[L-N(CH3)2] and (H[L-N(CH3)(2)])+ species, suggest that metal complexes formed by 5-(4'-N,N-dimethylamino)phenylazo-8-hydroxyquinoline should be considered as electron transport materials suitable for applications in photonic devices.
La Deda
Massimo
M
LASCAMM, Unita INSTM della Calabria, Dipartimento di Chimica, Universita degli Studi della Calabria, I-87036 Arcavacata di Rende (CS), Italy.
Grisolia
Annarita
A
Aiello
Iolinda
I
Crispini
Alessandra
A
Ghedini
Mauro
M
Belviso
Sandra
S
Amati
Mario
M
Lelj
Francesco
F