41 research outputs found
New Giant Fullerenes Identified as Chloro Derivatives: Isolated-Pentagon-Rule C<sub>108</sub>(1771)Cl<sub>12</sub> and C<sub>106</sub>(1155)Cl<sub>24</sub> as well as Nonclassical C<sub>104</sub>Cl<sub>24</sub>
High
temperature chlorination of HPLC fractions of higher fullerenes followed
by single crystal X-ray diffraction with the use of synchrotron radiation
resulted in the structure determination of IPR C<sub>106</sub>(1155)ÂCl<sub>24</sub> and IPR C<sub>108</sub>(1771)ÂCl<sub>12</sub>. C<sub>106</sub>(1155)ÂCl<sub>24</sub> is cocrystallized with C<sub>104</sub>Cl<sub>24</sub>, a chloride of the nonclassical isomer of C<sub>104</sub>. The moderately stable isomer C<sub>106</sub>(1155) and the most
stable C<sub>108</sub>(1771) represent so far the largest pristine
fullerenes with known cages
Steering the Geometry of Butterfly-Shaped Dimetal Carbide Cluster within a Carbon Cage via Trifluoromethylation of Y<sub>2</sub>C<sub>2</sub>@C<sub>82</sub>(6)
As
one of the largest sub-branches of endohedral clusterfullerenes,
dimetal carbide clusterfullerene (CCF) in the form of M<sub>2</sub>C<sub>2</sub>@C<sub>2<i>n</i></sub> is quite intriguing
since an alternative structure of M<sub>2</sub>@C<sub>2<i>n</i>+2</sub> as conventional dimetallofullerene may exist as well. Herein,
by using high-temperature trifluoromethylation followed by HPLC separation
and single-crystal X-ray diffraction study, we report for the first
time the unambiguous structural determination of yttrium (Y)-based
CCF as its trifluoromethyl derivatives, Y<sub>2</sub>C<sub>2</sub>@C<sub>82</sub>(6)Â(CF<sub>3</sub>)<sub>16</sub>. Four isomers of
Y<sub>2</sub>C<sub>2</sub>@C<sub>82</sub>(6)Â(CF<sub>3</sub>)<sub>16</sub> with different addition patterns of 16 CF<sub>3</sub> groups are
successfully isolated, and two Y atoms of the butterfly-shaped Y<sub>2</sub>C<sub>2</sub> cluster are coordinated by two cage pentagons
in each isomer. The butterfly geometry of Y<sub>2</sub>C<sub>2</sub> cluster varies significantly in the four Y<sub>2</sub>C<sub>2</sub>@C<sub>82</sub>(6)(CF<sub>3</sub>)<sub>16</sub> isomers, with Y···Y
distances ranging from 3.544
to 4.051 Ã… dependent on the relative positions of the two yttrium-coordinated
pentagons on the carbon cage
Five Isolated Pentagon Rule Isomers of Higher Fullerene C<sub>94</sub> Captured as Chlorides and CF<sub>3</sub> Derivatives: C<sub>94</sub>(34)Cl<sub>14</sub>, C<sub>94</sub>(61)Cl<sub>20</sub>, C<sub>94</sub>(133)Cl<sub>22</sub>, C<sub>94</sub>(42)(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)(CF<sub>3</sub>)<sub>18</sub>
High-temperature
chlorination and trifluoromethylation of C<sub>94</sub> isomeric mixtures
followed by single-crystal X-ray diffraction with the use of synchrotron
radiation resulted in the structure determination of C<sub>94</sub>(34)ÂCl<sub>14</sub>, C<sub>94</sub>(61)ÂCl<sub>20</sub>, C<sub>94</sub>(133)ÂCl<sub>22</sub>, C<sub>94</sub>(42)Â(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)Â(CF<sub>3</sub>)<sub>18</sub>. Their addition
patterns are stabilized by the formation of isolated Cî—»C bonds
and aromatic substructures. Four cage isomers of C<sub>94</sub> (nos.
34, 42, 43, and 133) have been experimentally confirmed for the first
time
Five Isolated Pentagon Rule Isomers of Higher Fullerene C<sub>94</sub> Captured as Chlorides and CF<sub>3</sub> Derivatives: C<sub>94</sub>(34)Cl<sub>14</sub>, C<sub>94</sub>(61)Cl<sub>20</sub>, C<sub>94</sub>(133)Cl<sub>22</sub>, C<sub>94</sub>(42)(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)(CF<sub>3</sub>)<sub>18</sub>
High-temperature
chlorination and trifluoromethylation of C<sub>94</sub> isomeric mixtures
followed by single-crystal X-ray diffraction with the use of synchrotron
radiation resulted in the structure determination of C<sub>94</sub>(34)ÂCl<sub>14</sub>, C<sub>94</sub>(61)ÂCl<sub>20</sub>, C<sub>94</sub>(133)ÂCl<sub>22</sub>, C<sub>94</sub>(42)Â(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)Â(CF<sub>3</sub>)<sub>18</sub>. Their addition
patterns are stabilized by the formation of isolated Cî—»C bonds
and aromatic substructures. Four cage isomers of C<sub>94</sub> (nos.
34, 42, 43, and 133) have been experimentally confirmed for the first
time
Five Isolated Pentagon Rule Isomers of Higher Fullerene C<sub>94</sub> Captured as Chlorides and CF<sub>3</sub> Derivatives: C<sub>94</sub>(34)Cl<sub>14</sub>, C<sub>94</sub>(61)Cl<sub>20</sub>, C<sub>94</sub>(133)Cl<sub>22</sub>, C<sub>94</sub>(42)(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)(CF<sub>3</sub>)<sub>18</sub>
High-temperature
chlorination and trifluoromethylation of C<sub>94</sub> isomeric mixtures
followed by single-crystal X-ray diffraction with the use of synchrotron
radiation resulted in the structure determination of C<sub>94</sub>(34)ÂCl<sub>14</sub>, C<sub>94</sub>(61)ÂCl<sub>20</sub>, C<sub>94</sub>(133)ÂCl<sub>22</sub>, C<sub>94</sub>(42)Â(CF<sub>3</sub>)<sub>16</sub>, and C<sub>94</sub>(43)Â(CF<sub>3</sub>)<sub>18</sub>. Their addition
patterns are stabilized by the formation of isolated Cî—»C bonds
and aromatic substructures. Four cage isomers of C<sub>94</sub> (nos.
34, 42, 43, and 133) have been experimentally confirmed for the first
time
Trifluoromethyl and Chloro Derivatives of a Higher Fullerene <i>D</i><sub>2</sub>‑C<sub>80</sub>(2): C<sub>80</sub>(CF<sub>3</sub>)<sub>12</sub> and C<sub>80</sub>Cl<sub>28</sub>
Two
derivatives of the low-abundant <i>D</i><sub>2</sub>-C<sub>80</sub> (isomer 2), C<sub>80</sub>(CF<sub>3</sub>)<sub>12</sub> and
C<sub>80</sub>Cl<sub>28</sub>, have been synthesized, isolated, and
structurally characterized by single-crystal X-ray crystallography.
Notably, the addition pattern of C<sub>80</sub>(CF<sub>3</sub>)<sub>12</sub> is the same as that of the known C<sub>80</sub>Cl<sub>12</sub>. The molecule of C<sub>80</sub>Cl<sub>28</sub> contains very short
(1.33 Å) and very long (up to 1.62 Å) C–C bonds in
its carbon cage
Imidazole-Functionalized Fullerene as a Vertically Phase-Separated Cathode Interfacial Layer of Inverted Ternary Polymer Solar Cells
By
using a facile one-pot nucleophilic addition reaction, we synthesized
a novel imidazole (IMZ)-functionalized fullerene (C<sub>60</sub>-IMZ),
and applied it as a third component of inverted ternary polymer solar
cells (PSCs), leading to dramatic efficiency enhancement. According
to FT-IR, XPS spectroscopic characterizations, and elemental analysis,
the chemical structure of C<sub>60</sub>-IMZ was determined with the
average IMZ addition number estimated to be six. The lowest unoccupied
molecular orbital (LUMO) level of C<sub>60</sub>-IMZ measured by cyclic
voltammetry was −3.63 eV, which is up-shifted relative to that
of 6,6-phenyl C<sub>61</sub>-butyric acid methyl ester (PC<sub>61</sub>BM). Upon doping C<sub>60</sub>-IMZ as a third component into an
active layer blend of polyÂ(3-hexylthiophene) (P3HT) and PC<sub>61</sub>BM, the power conversion efficiency (PCE) of the inverted ternary
PSCs was 3.4% under the optimized doping ratio of 10 wt %, dramatically
higher than that of the control device ITO/P3HT:PC<sub>61</sub>BM/MoO<sub>3</sub>/Ag based on the binary P3HT:PC<sub>61</sub>BM blend (1.3%).
The incorporation of C<sub>60</sub>-IMZ results in enhancement of
the absorption of P3HT:PC<sub>61</sub>BM blend film, increase of the
electron mobility of the device, and rougher film surface of the P3HT:PC<sub>61</sub>BM active layer beneficial for interfacial contact with the
Ag anode. Furthermore, C<sub>60</sub>-IMZ doped in P3HT:PC<sub>61</sub>BM blend may migrate to the surface of ITO cathode via vertical phase
separation as revealed by XPS depth analysis, consequently forming
a cathode interfacial layer (CIL), which can lower the work function
(WF) of ITO cathode. Thus, the interfacial contact between the active
layer and ITO cathode is improved, facilitating electron transport
from the active layer to ITO cathode. The effectiveness of C<sub>60</sub>-IMZ as a vertically phase-separated CIL on efficiency enhancement
of inverted ternary PSCs is further verified by doping it into another
active layer system comprised of a low-bandgap conjugated polymer,
polyÂ(thienoÂ[3,4-<i>b</i>]-thiophene/benzodithiophene) (PTB7),
blended with [6,6]-phenyl C<sub>71</sub>-butyric acid methyl ester
(PC<sub>71</sub>BM). Under the optimized C<sub>60</sub>-IMZ doping
ratio of 10 wt %, the PCE of the PTB7:PC<sub>71</sub>BM-based inverted
ternary PSC device reaches 5.3%, which is about 2 times higher than
that of the control binary device (2.6%)
Noncovalent Functionalization of Graphene Attaching [6,6]-Phenyl-C61-butyric Acid Methyl Ester (PCBM) and Application as Electron Extraction Layer of Polymer Solar Cells
A new graphene–fullerene composite (<b>rGO-pyrene-PCBM</b>), in which [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was attached onto reduced graphene oxide (rGO) <i>via</i> the noncovalent functionalization approach, was reported. The <b>pyrene-PCBM</b> moiety was synthesized <i>via</i> a facile esterification reaction, and pyrene was used as an anchoring bridge to link rGO and PCBM components. FTIR, UV–vis, and XPS spectroscopic characterizations were carried out to confirm the hybrid structure of <b>rGO-pyrene-PCBM</b>, and the composite formation is found to improve greatly the dispersity of rGO in DMF. The geometric configuration of <b>rGO-pyrene-PCBM</b> was studied by Raman, SEM, and AFM analyses, suggesting that the C<sub>60</sub> moiety is far from the graphene sheet and is bridged with the graphene sheet <i>via</i> the pyrene anchor. Finally <b>rGO-pyrene-PCBM</b> was successfully applied as electron extraction layer for P3HT:PCBM bulk heterojunction polymer solar cell (BHJ-PSC) devices, affording a PCE of 3.89%, which is enhanced by <i>ca.</i> 15% compared to that of the reference device without electron extraction layer (3.39%). Contrarily, the comparative devices incorporating the rGO or <b>pyrene-PCBM</b> component as electron extraction layer showed dramatically decreased PCE, indicating the importance of composite formation between rGO and <b>pyrene-PCBM</b> components for its electron extraction property