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Two series of aromatic compounds with perfluoroalkyl (RF ) groups of increasing length, 1,3,5,7-naphthalene(RF )4 and 1,3,5,7,9-corannulene(RF )5 , have been prepared and their electronic properties studied by low-temperature photoelectron spectroscopy (PES) (for gas-phase electron affinity measurements). These and many related compounds were also studied by DFT calculations. The data demonstrate unambiguously that the electron-withdrawing ability of RF substituents increases significantly and uniformly from CF3 to C2 F5 to n-C3 F7 to n-C4 F9 .

A fluorinated faux hawk fullerene with comparable OPV-relevant TRMC performance and far greater thermal stability than PCBM is reported., Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. 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 C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(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/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)– can undergo facile intramolecular SNAr 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 SNAr 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 C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E 1/2(0/–) values of 2 and C60, –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.

Fullerenes and fullerene derivatives have attracted much attention due to their interesting optical and electronic properties. For example, further chemical elaborations of fullerenes possessing cyclo‐adducts (ie., phenyl‐C61‐butyric acid methyl ester, PCBM,1 and mono‐indene-C60, ICMA2) have shown promising use in photovoltaic energy conversion. Mono‐hydrofullerenes, C60RH, were shown as effective synthons for novel molecules3 with interesting physicochemical properties for various applications. The C‒H bond activation utilizing the acidic fullerenyl C60‒H proton can be realized by the use of strong bases. For instance, the dimerization of two RC60· radicals using NaOH in the presence of C60RH was used to form RC60‒C60R.4 In this work, we use the labile hydrogen atom on C60RH as a synthetic handle for further chemical elaborations, resulting in a novel perfluoroarylfullerene. One such product, a "fullerene-with-a-mohawk," was realized by the use of a base or by an one‐electron reductant. Products were characterized by 19F and 1H NMR spectroscopy, mass spectrometry, cyclic voltammetry, X‐ray crystallography, and DFT calculations. References (1) Reyes-Reyes, M.; Kim, K.; Carroll, D. L. Appl. Phys. Lett. 2005, 87, 083506. (2) Coffey, D. C.; Larson, B. W.; Hains, A. W.; Whitaker, J. B.; Kopidakis, N.; Boltalina, O. V.; Strauss, S. H.; Rumbles, G. J. Phys. Chem. C 2012, 116, 8916. (3) Allard, E.; Cheng, F.; Chopin, S.; Delaunay, J.; Rondeau, D.; Cousseau, J. New J. Chem. 2003, 27, 188. (4) Lu, S.; Jin, T.; Bao, M.; Yamamoto, Y. Org. Lett. 2012, 14, 3466.