A faux hawk fullerene with PCBM-like propertiesElectronic supplementary information (ESI) available: Additional figures and tables described in the text. CSD-428507. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc02970d
Reaction of C 60 , C 6 F 5 CF 2 I, and SnH( n -Bu) 3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C 60 (CF 2 C 6 F 5 )H ( 1 ) and 1,9-C 60 ( cyclo -CF 2 (2-C 6 F 4 )) ( 2 ). The highest isolated yield of 1 was 35% based on C 60 . Depending on the reaction condi...
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| Main Authors | , , , , , , , , , , , |
|---|---|
| Format | Journal Article |
| Language | English |
| Published |
16.02.2015
|
| Online Access | Get full text |
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| Summary: | Reaction of C
60
, C
6
F
5
CF
2
I, and SnH(
n
-Bu)
3
produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C
60
(CF
2
C
6
F
5
)H (
1
) and 1,9-C
60
(
cyclo
-CF
2
(2-C
6
F
4
)) (
2
). The highest isolated yield of
1
was 35% based on C
60
. Depending on the reaction conditions, the relative amounts of
1
and
2
generated
in situ
were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C
60
. Compound
1
is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to
2
upon addition of Sn
2
(
n
-Bu)
6
at this temperature. In contrast, complete conversion of
1
to
2
occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C
6
D
6
by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp
2
). DFT calculations indicate that when
1
is deprotonated, the anion C
60
(CF
2
C
6
F
5
)
−
can undergo facile intramolecular S
N
Ar annulation to form
2
with concomitant loss of F
−
. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an S
N
Ar nucleophile towards an aromatic C-F bond. The gas-phase electron affinity (EA) of
2
was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C
60
and higher by 0.18(1) eV than the EA of phenyl-C
61
-butyric acid methyl ester (PCBM). In contrast, the relative
E
1/2
(0/−) values of
2
and C
60
, −0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the
E
1/2
(0/−) of PCBM is −0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends of
2
and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of
2
was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene-fullerene interactions with centroid centroid ( ) distances of ≤10.34 Å is significantly greater, and the average distance is shorter, for
2
(10 nearest neighbors; ave. distance = 10.09 Å) than for solvent-free crystals of PCBM (7 nearest neighbors; ave. distance = 10.17 Å). Finally, the thermal stability of
2
was found to be far greater than that of PCBM.
A fluorinated faux hawk fullerene with comparable OPV-relevant TRMC performance and far greater thermal stability than PCBM is reported. |
|---|---|
| Bibliography: | For ESI and crystallographic data in CIF or other electronic format see DOI 428507 Electronic supplementary information (ESI) available: Additional figures and tables described in the text. CSD- 10.1039/c4sc02970d |
| ISSN: | 2041-6520 2041-6539 |
| DOI: | 10.1039/c4sc02970d |