ИСТИНА

The work is aimed on the synthesis of new fluorescent materials by alkylation of the readily available Cs C70(CF3)8 dianion. Synthesis pathway and fluorescent properties of the products are discussed. During past decades in fullerene chemistry, the main focus was placed on utilizing fullerene-based compounds as electron acceptors in polymer-based solar cells. Fluorescent properties of some of these materials were reported, but due to low quantum yields and poor synthetic availability, this side of fullerene research remained virtually untouched until a high quantum yield (68%) red emission of the particular isomer of C70(CF3)10 was reported. [1] Then in 2017, a range of C70 derivatives were prepared spanning the full visible range in emission with the highest scoring one featuring similar red emission with considerably smaller 18% quantum yield. [2] However, the major problem of the first work is the poor synthetic availability of the abovementioned isomer with it being produced only as a minor product of C70 trifluoromethylation with the main products being Cs-C70(CF3)8 and C1-C70(CF3)10 featuring drastically lower 0.1% and 4.7% fluorescent quantum yields respectively. Shlegel diagram Formula Cs-C70(CF3)8 C1-C70(CF3)10 C1-C70(CF3)10 (minor) Fluorescence QY 0.1% 4.7% 68% In the work [2] the idea behind the synthesis was functionalization of Cs-C70(OMe)8 and C1 C70(OMe)10 templates, which has similar addend locations to major Cs-C70(CF3)8 and C1 C70(CF3)10, by means of Bingel reaction which doesn’t generally happen with >50% yields. Therefore, in our work, we focused on the effective functionalization of readily available and thermally stable Cs C70(CF3)8 through its anion generation. Cs-C70(CF3)8 was first hydrogenated to yield single isomer of Cs-C70(CF3)8H2 (using the method published by our group earlier [3]). The hydride was later deprotonated forming Cs C70(CF3)82- and alkyl halides were added to the reaction mixture. Fluorescent properties of all fullerene-based products including the hydride were investigated. The reported study was funded by RFBR according to the research project № 18-33-01192 [1] K. P. Castro, Y. Jin, J. J. Rack, S. H. Strauss, O. V. Boltalina, and A. A. Popov, “Perfluoroalkyl [70]-fullerenes as robust highly-luminescent fluorocarbons, or position of one CF3 group matters,” J. Phys. Chem. Lett., vol. 4, no. 15, pp. 2500–2507, 2013. [2] N. Lou, Y. Li, and L. Gan, “Synthesis of C70-Based Fluorophores through Sequential Functionalization to Form Isomerically Pure Multiadducts,” Angew. Chemie - Int. Ed., vol. 56, no. 9, pp. 2403–2407, 2017. [3] V. A. Brotsman et al., “Reductive Hydrogenation of Cs-C70(CF3)8 and C1-C70(CF3)10,” Chem. - An Asian J., vol. 11, no. 13, pp. 1945–1954, Jul. 2016.