Sensors 2009, 9(5), 3604-3626; doi:10.3390/s90503604

Metal Ion Enhanced Charge Transfer in a Terpyridine-bis-Pyrene System

1email, 2, 2email and 1,* email
Received: 7 April 2009; in revised form: 8 May 2009 / Accepted: 12 May 2009 / Published: 13 May 2009
(This article belongs to the Special Issue Dendritic Sensors: From Dendrimer Molecules to Dendritic Cells)
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Abstract: The synthesis, electrochemical and photophysical properties of a branched molecule 3,5-bis(pyrene-1-yl)-4'-phenyl-2,2':6',2''-terpyridine are reported. Spectroscopy in different solvents reveals that an optical electron transfer from the pyrene donor to the terpyridyl electron acceptor can occur in polar media, as the system displays both charge transfer (CT) absorption and CT emission. Furthermore, the study of the zinc complex as well as the bis-protonated form shows an enhancement of the electron transfer character of the system, by an increase of the acceptor strength. This is accompanied by a large increase of the non-radiative processes. With sub-nanosecond transient absorption spectroscopy, the CT state, consisting of the pyrene radical cation and the terpyridine radical anion, has been detected. At room temperature, the study of the nanosecond transient absorption spectra reveals the formation of a low-lying triplet excited state that we attribute to the pyrene moiety through which the CT state decays. At 77K, the absence of the terpyridine triplet emission also suggests the population of a low-lying triplet state of the pyrene unit.
Keywords: branched molecules; spectroscopy; ion complexation; excited state absorption; emission; molecular polarity sensor
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MDPI and ACS Style

D’Aléo, A.; Cecchetto, E.; De Cola, L.; Williams, R.M. Metal Ion Enhanced Charge Transfer in a Terpyridine-bis-Pyrene System. Sensors 2009, 9, 3604-3626.

AMA Style

D’Aléo A, Cecchetto E, De Cola L, Williams RM. Metal Ion Enhanced Charge Transfer in a Terpyridine-bis-Pyrene System. Sensors. 2009; 9(5):3604-3626.

Chicago/Turabian Style

D’Aléo, Anthony; Cecchetto, Elio; De Cola, Luisa; Williams, René M. 2009. "Metal Ion Enhanced Charge Transfer in a Terpyridine-bis-Pyrene System." Sensors 9, no. 5: 3604-3626.

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