Abstract
The electronic properties of tetrathiafulvalene (TTF) can be tuned by attaching electron-donating or electron-withdrawing substituents. An electron-rich macrocyclic polyether containing two TTF units of different constitutions, namely 4,4′-bis(hydroxymethyl)tetrathiafulvalene (OTTFO) and 4,4′-bisthiotetrathiafulvalene (STTFS), has been synthesized. On two-electron oxidation, a hetero radical dimer is formed between OTTFO • and STTFS•. The redox behavior of the macrocyclic polyether has been investigated by electrochemical techniques and UV-vis and electron paramagnetic resonance (EPR) spectroscopies. The [2]catenane in which the macrocyclic polyether is mechanically interlocked with the cyclobis(paraquat-p-phenylene) (CBPQT4+) ring has also been prepared using template-directed protocols. In the case of the [2]catenane, the formation of the TTF hetero radical dimer is prevented sterically by the CBPQT 4+ ring. After a one-electron oxidation, a 70:30 ratio of OTTFO • to STTFS• is present at equilibrium, and, as a result, two translational isomers of the [2]catenane associated with these electronically different isomeric states transpire. EPR titration spectroscopy and simulations reveal that the radical states of the two constitutionally different TTF units in the [2]catenane still experience long-range electronic intramolecular coupling interactions, despite the presence of the CBPQT 4+ ring, when one or both of them are oxidized to the radical cationic state. These findings in the case of both the free macrocyclic polyether and the [2]catenane have led to a deeper fundamental understanding of the mechanism of radical cation dimer formation between constitutionally different TTF units.
| Original language | English |
|---|---|
| Pages (from-to) | 19136-19145 |
| Number of pages | 10 |
| Journal | Journal of the American Chemical Society |
| Volume | 134 |
| Issue number | 46 |
| DOIs | |
| Publication status | Published - Nov 21 2012 |
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ASJC Scopus subject areas
- Chemistry(all)
- Catalysis
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Tetrathiafulvalene hetero radical cation dimerization in a redox-active [2]catenane. / Wang, Cheng; Dyar, Scott M.; Cao, Dennis; Fahrenbach, Albert C.; Horwitz, Noah; Colvin, Michael T.; Carmieli, Raanan; Stern, Charlotte L.; Dey, Sanjeev K.; Wasielewski, Michael R; Stoddart, J. Fraser.
In: Journal of the American Chemical Society, Vol. 134, No. 46, 21.11.2012, p. 19136-19145.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tetrathiafulvalene hetero radical cation dimerization in a redox-active [2]catenane
AU - Wang, Cheng
AU - Dyar, Scott M.
AU - Cao, Dennis
AU - Fahrenbach, Albert C.
AU - Horwitz, Noah
AU - Colvin, Michael T.
AU - Carmieli, Raanan
AU - Stern, Charlotte L.
AU - Dey, Sanjeev K.
AU - Wasielewski, Michael R
AU - Stoddart, J. Fraser
PY - 2012/11/21
Y1 - 2012/11/21
N2 - The electronic properties of tetrathiafulvalene (TTF) can be tuned by attaching electron-donating or electron-withdrawing substituents. An electron-rich macrocyclic polyether containing two TTF units of different constitutions, namely 4,4′-bis(hydroxymethyl)tetrathiafulvalene (OTTFO) and 4,4′-bisthiotetrathiafulvalene (STTFS), has been synthesized. On two-electron oxidation, a hetero radical dimer is formed between OTTFO • and STTFS•. The redox behavior of the macrocyclic polyether has been investigated by electrochemical techniques and UV-vis and electron paramagnetic resonance (EPR) spectroscopies. The [2]catenane in which the macrocyclic polyether is mechanically interlocked with the cyclobis(paraquat-p-phenylene) (CBPQT4+) ring has also been prepared using template-directed protocols. In the case of the [2]catenane, the formation of the TTF hetero radical dimer is prevented sterically by the CBPQT 4+ ring. After a one-electron oxidation, a 70:30 ratio of OTTFO • to STTFS• is present at equilibrium, and, as a result, two translational isomers of the [2]catenane associated with these electronically different isomeric states transpire. EPR titration spectroscopy and simulations reveal that the radical states of the two constitutionally different TTF units in the [2]catenane still experience long-range electronic intramolecular coupling interactions, despite the presence of the CBPQT 4+ ring, when one or both of them are oxidized to the radical cationic state. These findings in the case of both the free macrocyclic polyether and the [2]catenane have led to a deeper fundamental understanding of the mechanism of radical cation dimer formation between constitutionally different TTF units.
AB - The electronic properties of tetrathiafulvalene (TTF) can be tuned by attaching electron-donating or electron-withdrawing substituents. An electron-rich macrocyclic polyether containing two TTF units of different constitutions, namely 4,4′-bis(hydroxymethyl)tetrathiafulvalene (OTTFO) and 4,4′-bisthiotetrathiafulvalene (STTFS), has been synthesized. On two-electron oxidation, a hetero radical dimer is formed between OTTFO • and STTFS•. The redox behavior of the macrocyclic polyether has been investigated by electrochemical techniques and UV-vis and electron paramagnetic resonance (EPR) spectroscopies. The [2]catenane in which the macrocyclic polyether is mechanically interlocked with the cyclobis(paraquat-p-phenylene) (CBPQT4+) ring has also been prepared using template-directed protocols. In the case of the [2]catenane, the formation of the TTF hetero radical dimer is prevented sterically by the CBPQT 4+ ring. After a one-electron oxidation, a 70:30 ratio of OTTFO • to STTFS• is present at equilibrium, and, as a result, two translational isomers of the [2]catenane associated with these electronically different isomeric states transpire. EPR titration spectroscopy and simulations reveal that the radical states of the two constitutionally different TTF units in the [2]catenane still experience long-range electronic intramolecular coupling interactions, despite the presence of the CBPQT 4+ ring, when one or both of them are oxidized to the radical cationic state. These findings in the case of both the free macrocyclic polyether and the [2]catenane have led to a deeper fundamental understanding of the mechanism of radical cation dimer formation between constitutionally different TTF units.
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U2 - 10.1021/ja307577t
DO - 10.1021/ja307577t
M3 - Article
VL - 134
SP - 19136
EP - 19145
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 46
ER -