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The availability of well-defined modified graphene derivatives such as fluorographene, graphane, thiographene or hydroxygraphene is of pivotal importance for tuning the resulting material properties in numerous potential applications. A series of fluorinated graphene with various contents of fluorine was synthesized by a simple fluorination procedure in an autoclave with a nitrogen/fluorine atmosphere at different exposure times and temperatures. To investigate the composition, structure and properties all samples were characterized in detail by a number of analytical techniques such as SEM, XRD, EDS, AFM, STEM, combustible elemental analysis, STA, XPS, Raman spectroscopy, UV-VIS spectroscopy and cyclic voltammetry. The fully fluorinated graphene with the overall stoichiometry C1F1.05 had a bright white color indicating a significant change of band-gap. In comparison to other samples such a high concentration of fluorine led to the occurrence of exotic thermal behavior, strong luminescence in the visible spectral region and also the unique super-hydrophobic behavior observed on the material surface. The described tunable fluorination should pave the way to fluorographene based devices with tailored properties.

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Amino acid [closo-1-CB(9)H(8)-1-COO-10-NH(3)](-) (4) was prepared by amination of iodo acid [closo-1-CB(9)H(8)-1-COOH-10-I](-) (1) with LiHMDS in a practical and reproducible manner. The apparent dissociation constants, pK(2) = 5.6 and pK(1) > 11, were measured for 4[NMe(4)] in 50% aq. EtOH. Diazotization of 4 with NO(+)PF(6)(-) under mildly basic conditions afforded stable dinitrogen acid [closo-1-CB(9)H(8)-1-COOH-10-N(2)] (5). Activation parameters (DeltaH(++) = 33.9 +/- 1.4 kcal mol(-1) and DeltaS(++) = 10 +/- 3.5 cal mol(-1) K(-1)) for thermolysis of its methyl ester [closo-1-CB(9)H(8)-1-COOMe-10-N(2)] (11) in PhCN were established, and the heterolysis of the B-N bond is believed to be the rate-determining step. Electrochemical analysis showed a partially reversible reduction process for 11 (E(1/2)(red) = -1.03 V) and 5(-) (E(1/2)(red) = -1.21 V), which are more cathodic than reduction of [closo-1-CB(9)H(9)-1-N(2)] (17). The dinitrogen acid 5 was reacted with pyridine and N,N-dimethylthioformamide, to form pyridine acid 6 and protected mercapto acid 7, respectively, through a boronium ylide intermediate 18. Compound 7 was converted to sulfonium acid 8. The molecular and crystal structures for 5 [C(2)H(9)B(9)N(2)O(2) monoclinic, P2(1)/n, a = 7.022(2) A, b = 11.389(4) A, c = 12.815(4) A, beta = 96.212(5) degrees ; V = 1018.8(6) A(3), Z = 4,], 6 [C(7)H(14)B(9)NO(2), monoclinic, P2(1)/n, a = 14.275(4) A, b = 12.184(3) A, c = 30.538(8) A, beta = 95.377(4) degrees ; V = 5288(3) A(3), Z = 16], and 8 [C(7)H(19)B(9)O(2)S, monoclinic, P2(1)/c, a = 15.988(5) A, b = 19.377(6) A, c = 9.655(3) A, beta = 98.348(5) degrees; V = 2959.4(16) A(3), Z = 8] were determined by X-ray crystallography and compared with results of density functional theory (DFT) and MP2 calculations. Electronic structures of 5, 6, and related species were elucidated with electronic spectroscopy and assessed computationally at the B3LYP/6-31G(d,p), MP2/6-31G(d,p), and ZINDO//MP2 levels of theory.

Salts of 12-alkyl and 12-phenyl derivatives of the CB11H12 - anion are prepared in 50−60% yields from the 12-iodo-CB11H11 - anion by Pd-catalyzed cross-coupling with Grignard reagents. The tropylium ylide 12-C7H6 +-CB11H11 - is made in 54% yield by reaction of C7H7 + with CB11H12 -. Its ground-state dipole moment is 11.25 ± 0.1 D and its first hyperpolarizability is β = 236 × 10-30 esu at 1064 nm, as determined by hyper-Rayleigh scattering measurement. This value is ten times that of p-nitroaniline and is surprisingly large considering that the compound is colorless.

Water-soluble highly fluorinated graphite oxide is a promising candidate for applications in biosensing and for fluorescent probes due to its variable fluorescence properties. We report on a simple process for the preparation of a fluorinated graphite oxide (FGO). This process is based on fluorination of graphite oxide (GO) in a fluorine atmosphere at an elevated temperature and pressure. We used two different GO precursors, which were prepared by Staudenmaier and Hummers methods. The method of GO synthesis has a strong influence on the concentration of fluorine in the obtained product. The mechanism of GO fluorination is associated with the presence of reactive groups, mostly epoxides, and is accompanied by etching of graphite oxide. Our analyses highlighted that the FGO prepared by Hummers method contains a significantly higher amount of bounded fluorine and can be used as a starting material for the synthesis of chemically reduced fluorine doped graphene. Water soluble fluorinated graphene can be easily processed in aqueous solutions to create hydrophilic particles and films with tunable fluorescence properties. Experimental sectionGraphite oxides were prepared, similarly to Staudenmaier method 21 and Hummers 22 method, from pure graphite microparticles (2-15 mm, 99.9995%, from Alfa Aesar). Sulfuric acid

Fluorinated graphenes (F-G) might inevitably be released into the environment through disposal and wearing of future commercial products incorporated with F-G. Therefore, we determined their cytotoxicity in this study.

The HRS ) 236 × 10 -30 esu first hyperpolarizability of the title ylide in CHCl 3 (1064 nm) obtained from hyper-Rayleigh scattering (HRS), using p-nitroaniline (pNA) The first molecular hyperpolarizability of the title ylide is within experimental error of that of pNA. With the new value for this standard, this is HRS ) 7.2 × 10 -30 esu, in much improved agreement with the INDO/S result calculated at zero frequency, zzz ) 1.7 × 10 -30 (the INDO/S result for pNA is zzz ) 18 × 10 -30 ). The structure of the dimeric porphyrin host 1 was inadvertently omitted.