Abstract
Radical templation centered around a heterotrisradical tricationic inclusion complex DB•+⊂DAPQT2(•+), assembled from an equimolar mixture of a disubstituted 4,4′-bipyridinium radical cation (DB•+) and an asymmetric cyclophane bisradical dication (DAPQT2(•+)), affords a symmetric [2]catenane (SC·7PF6) and an asymmetric [2]catenane (AC·7PF6) on reaction of the 1:1 complex with diazapyrene and bipyridine, respectively. Both these highly charged [2]catenanes have been isolated as air-stable monoradicals and characterized by EPR spectroscopy. X-ray crystallography suggests that the unpaired electrons are delocalized in each case across two inner 4,4′-bipyridinium (BIPY2+) units forming a mixed-valence (BIPY2)•3+ state inside both [2]catenanes, an observation which is in good agreement with spin-density calculations using density functional theory. Electrochemical studies indicate that by replacing the BIPY2+ units in homo[2]catenane HC•7+ - composed of two mechanically interlocked cyclobis(paraquat-p-phenylene) rings - with "zero", one, and two more highly conjugated diazapyrenium dication (DAP2+) units, respectively, a consecutive series of five, six, and seven redox states can be accessed in the resulting SC·7PF6 (0, 4+, 6+, 7+, and 8+), HC·7PF6 (0, 2+, 4+, 6+, 7+, and 8+), and AC·7PF6 (0, 1+, 2+, 4+, 6+, 7+, and 8+), respectively. These unique [2]catenanes present a promising prototype for the fabrication of high-density data memories.
| Original language | English |
|---|---|
| Pages (from-to) | 12704-12709 |
| Number of pages | 6 |
| Journal | Journal of the American Chemical Society |
| Volume | 139 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - Sep 13 2017 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Mechanical-Bond-Protected, Air-Stable Radicals. / Sun, Junling; Liu, Zhichang; Liu, Wei Guang; Wu, Yilei; Wang, Yuping; Barnes, Jonathan C.; Hermann, Keith R.; Goddard, William A.; Wasielewski, Michael R; Stoddart, J. Fraser.
In: Journal of the American Chemical Society, Vol. 139, No. 36, 13.09.2017, p. 12704-12709.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanical-Bond-Protected, Air-Stable Radicals
AU - Sun, Junling
AU - Liu, Zhichang
AU - Liu, Wei Guang
AU - Wu, Yilei
AU - Wang, Yuping
AU - Barnes, Jonathan C.
AU - Hermann, Keith R.
AU - Goddard, William A.
AU - Wasielewski, Michael R
AU - Stoddart, J. Fraser
PY - 2017/9/13
Y1 - 2017/9/13
N2 - Radical templation centered around a heterotrisradical tricationic inclusion complex DB•+⊂DAPQT2(•+), assembled from an equimolar mixture of a disubstituted 4,4′-bipyridinium radical cation (DB•+) and an asymmetric cyclophane bisradical dication (DAPQT2(•+)), affords a symmetric [2]catenane (SC·7PF6) and an asymmetric [2]catenane (AC·7PF6) on reaction of the 1:1 complex with diazapyrene and bipyridine, respectively. Both these highly charged [2]catenanes have been isolated as air-stable monoradicals and characterized by EPR spectroscopy. X-ray crystallography suggests that the unpaired electrons are delocalized in each case across two inner 4,4′-bipyridinium (BIPY2+) units forming a mixed-valence (BIPY2)•3+ state inside both [2]catenanes, an observation which is in good agreement with spin-density calculations using density functional theory. Electrochemical studies indicate that by replacing the BIPY2+ units in homo[2]catenane HC•7+ - composed of two mechanically interlocked cyclobis(paraquat-p-phenylene) rings - with "zero", one, and two more highly conjugated diazapyrenium dication (DAP2+) units, respectively, a consecutive series of five, six, and seven redox states can be accessed in the resulting SC·7PF6 (0, 4+, 6+, 7+, and 8+), HC·7PF6 (0, 2+, 4+, 6+, 7+, and 8+), and AC·7PF6 (0, 1+, 2+, 4+, 6+, 7+, and 8+), respectively. These unique [2]catenanes present a promising prototype for the fabrication of high-density data memories.
AB - Radical templation centered around a heterotrisradical tricationic inclusion complex DB•+⊂DAPQT2(•+), assembled from an equimolar mixture of a disubstituted 4,4′-bipyridinium radical cation (DB•+) and an asymmetric cyclophane bisradical dication (DAPQT2(•+)), affords a symmetric [2]catenane (SC·7PF6) and an asymmetric [2]catenane (AC·7PF6) on reaction of the 1:1 complex with diazapyrene and bipyridine, respectively. Both these highly charged [2]catenanes have been isolated as air-stable monoradicals and characterized by EPR spectroscopy. X-ray crystallography suggests that the unpaired electrons are delocalized in each case across two inner 4,4′-bipyridinium (BIPY2+) units forming a mixed-valence (BIPY2)•3+ state inside both [2]catenanes, an observation which is in good agreement with spin-density calculations using density functional theory. Electrochemical studies indicate that by replacing the BIPY2+ units in homo[2]catenane HC•7+ - composed of two mechanically interlocked cyclobis(paraquat-p-phenylene) rings - with "zero", one, and two more highly conjugated diazapyrenium dication (DAP2+) units, respectively, a consecutive series of five, six, and seven redox states can be accessed in the resulting SC·7PF6 (0, 4+, 6+, 7+, and 8+), HC·7PF6 (0, 2+, 4+, 6+, 7+, and 8+), and AC·7PF6 (0, 1+, 2+, 4+, 6+, 7+, and 8+), respectively. These unique [2]catenanes present a promising prototype for the fabrication of high-density data memories.
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U2 - 10.1021/jacs.7b06857
DO - 10.1021/jacs.7b06857
M3 - Article
VL - 139
SP - 12704
EP - 12709
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 36
ER -