Control of electron transfer in supramolecular systems
Artikel i vetenskaplig tidskrift, 2001

The fluorescence quantum yield of zinc porphyrin (ZnP) covalently linked to 9,10-bis(phenylethynyl)anthracene (AB) is strongly dependent upon the solvent properties. The bichromophoric system ZnP-AB exhibits 'normal' zinc porphyrin fluorescence in solvents that cannot coordinate to the central zinc atom. In contrast, if a Lewis base, such as pyridine, is added to a sufficiently polar solvent, the fluorescence is significantly quenched. Picosecond transient absorption measurements, in conjunction with fluorescence quenching and cyclic voltammetric measurements, suggest that the quenching mechanism is intramolecular electron transfer from ZnP to AB. The charge separated state, ZnP.+-AB(.-), has a lifetime of not more than 220 ps before recombining. If a secondary electron acceptor, iron(III) porphyrin (FeP), is covalently connected to the AB unit, a second electron transfer from AB(.-) to FeP occurs and the charge separated state, ZnP.+-AB-FeP.-, has a lifetime of at least 5 ns. This demonstrates that electron transfer might be sensitively tuned (switched on) by specific solvent effects. (C) 2001 Elsevier Science BN. All rights reserved.

Författare

Kristine Kilså

Institutionen för fysikalisk kemi

A. N. Macpherson

T. Gillbro

Jerker Mårtensson

Institutionen för organisk kemi

Bo Albinsson

Institutionen för fysikalisk kemi

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

1386-1425 (ISSN)

Vol. 57 2213-2227

Styrkeområden

Nanovetenskap och nanoteknik

Fundament

Grundläggande vetenskaper

Ämneskategorier

Kemi