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Coordinative Interactions between Porphyrins and C 60 , La@C 82 , and La 2 @C 80
Author(s) -
Tsuchiya Takahiro,
Rudolf Marc,
Wolfrum Silke,
Radhakrishnan Shankara Gayathri,
Aoyama Ryo,
Yokosawa Yuya,
Oshima Azusa,
Akasaka Takeshi,
Nagase Shigeru,
Guldi Dirk M.
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201202661
Subject(s) - chemistry , excited state , electron transfer , metallofullerene , fullerene , electron donor , electron acceptor , ground state , kinetics , photochemistry , crystallography , atomic physics , catalysis , physics , biochemistry , organic chemistry , quantum mechanics
For the first time, a C 60 derivative ( 1 ) and two different lanthanum metallofullerene derivatives, La@C 82 Py ( 2 ) and La 2 @C 80 Py ( 3 ), that feature a pyridyl group as a coordination site for transition‐metal ions have been synthesized and integrated as electron acceptors into coordinative electron‐donor/electron‐acceptor hybrids. Zinc tetraphenylporphyrin ( ZnP ) served as an excited‐state electron donor in this respect. Our investigations, by means of steady‐state and time‐resolved photophysical techniques found that electron transfer governs the excited‐state deactivation in all of these systems, namely 1/ZnP , 2/ZnP , and 3/ZnP , whereas, in the ground state, notable electronic interactions are lacking. Variation of the electron‐accepting fullerene or metallofullerene moieties provides the incentive for fine‐tuning the binding constants, the charge‐separation kinetics, and the charge‐recombination kinetics. To this end, the binding constants, which ranged from log K assoc =3.94–4.38, are dominated by axial coordination, with minor contributions from the orbital overlap of the curved and planar π systems. The charge‐separation and charge‐recombination kinetics, which are in the order of 10 10 and 10 8 s −1 , relate to the reduction potential of the fullerene and metallofullerenes, respectively.