Near-IR excitation transfer and electron transfer in a BF2-chelated dipyrromethane-azadipyrromethane dyad and triad

dc.contributor.author	El-Khouly, Mohamed E.
dc.contributor.author	Amin, Anu N.
dc.contributor.author	Zandler, Melvin E.
dc.contributor.author	Fukuzumi, Shunichi
dc.contributor.author	D'Souza, Francis
dc.date.accessioned	2012-06-14T16:32:20Z
dc.date.available	2012-06-14T16:32:20Z
dc.date.issued	2012-04
dc.identifier.citation	El-Khouly ME, AN Amin, ME Zandler, S Fukuzumi, and F D'Souza. 2012. "Near-IR Excitation Transfer and Electron Transfer in a BF(2) -Chelated Dipyrromethane-Azadipyrromethane Dyad and Triad". Chemistry (Weinheim an Der Bergstrasse, Germany). 18 (17): 5239-47.	en_US
dc.identifier.issn	0947-6539
dc.identifier.uri	http://hdl.handle.net/10057/5124
dc.identifier.uri	http://dx.doi.org/10.1002/chem.201103074
dc.description	Click on the DOI link below to access the article (may not be free).	en_US
dc.description.abstract	A molecular dyad and triad, comprised of a known photosensitizer, BF2-chelated dipyrromethane (BDP), covalently linked to its structural analog and near-IR emitting sensitizer, BF2-chelated tetraarylazadipyrromethane (ADP), have been newly synthesized and the photoinduced energy and electron transfer were examined by femtosecond and nanosecond laser flash photolysis. The structural integrity of the newly synthesized compounds has been established by spectroscopic, electrochemical, and computational methods. The DFT calculations revealed a molecular-clip-type structure for the triad, in which the BDP and ADP entities are separated by about 14 angstrom with a dihedral angle between the fluorophores of around 70 degrees. Differential pulse voltammetry studies have revealed the redox states, allowing estimation of the energies of the charge-separated states. Such calculations revealed a charge separation from the singlet excited BDP (1BDP) to ADP (BDP.+-ADP.-) to be energetical! ly favorable in nonpolar toluene and in polar benzonitrile. In addition, the excitation transfer from the singlet BDP to ADP is also envisioned due to good spectral overlap of the BDP emission and ADP absorption spectra. Femtosecond laser flash photolysis studies provided concrete evidence for the occurrence of energy transfer from 1BDP to ADP (in benzonitrile and toluene) and electron transfer from BDP to 1ADP* (in benzonitrile, but not in toluene). The kinetic study of energy transfer was measured by monitoring the rise of the ADP emission and revealed fast energy transfer (ca. 1011 s-1) in these molecular systems. The kinetics of electron transfer via 1ADP, measured by monitoring the decay of the singlet ADP at λ=820 nm, revealed a relatively fast charge-separation process from BDP to 1ADP. These findings suggest the potential of the examined ADPBDP molecules to be efficient photosynthetic antenna and reaction center models.	en_US
dc.language.iso	en_US	en_US
dc.publisher	WILEY-V C H VERLAG GMBH	en_US
dc.relation.ispartofseries	Chemistry (Weinheim an Der Bergstrasse, Germany);2012, V.18, No.17
dc.subject	Chelates	en_US
dc.subject	Donor-acceptor systems	en_US
dc.subject	Electron transfer	en_US
dc.subject	Energy transfer	en_US
dc.subject	Near-IR emitters	en_US
dc.title	Near-IR excitation transfer and electron transfer in a BF2-chelated dipyrromethane-azadipyrromethane dyad and triad	en_US
dc.type	Article	en_US
dc.description.version	Peer reviewed
dc.rights.holder	Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim