Anodic Oxidation of 18 Halogenated and/or Methylated Derivatives of CB11H12.

Anodic oxidation of [CB11H12]- and 18 of its halogenated and/or methylated derivatives was examined. Reversible oxidation was found for four of the anions in liquid SO2 and for four more in 1,1,1,3,3,3-hexafluoroisopropyl alcohol. The oxidation occurred at ∼1 V (for [CB11Me12]-) up to more than 4 V (for [1-H-(2-6)-F5-(7-12)-(CF3)6-CB11]-) relative to ferrocene/ferricinium. The anodic peak potentials are reproduced by a set of additive position-sensitive substituent increments.

Metal Complexes with Very Large Dipole Moments: the Anionic Carborane Nitriles 12-NC-CB11X11(-) (X = H, F, CH3) as Ligands on Pt(II) and Pd(II).

The anionic nitriles 1-R-12-NC-CB11H10(-) (R = H, CH3, I, COOH), 12-NC-1-H-CB11Me10(-), and 12-NC-1-H-CB11F10(-) were prepared, and three of them were examined for complex formation with (Et3P)2Pt(II) and (Et3P)2Pd(II). Several stable internally charge-compensated zwitterionic complexes were obtained and characterized. RI-BP86/SV(P) calculations suggest that their dipole moments exceed 20 D. An attempt to measure the dipole moments in solution failed due to insufficient solubility in solvents of low polarity.

Fluorinated graphenes as advanced biosensors - effect of fluorine coverage on electron transfer properties and adsorption of biomolecules.

Graphene derivatives are promising materials for the electrochemical sensing of diverse biomolecules and development of new biosensors owing to their improved electron transfer kinetics compared to pristine graphene. Here, we report complex electrochemical behavior and electrocatalytic performance of variously fluorinated graphene derivatives prepared by reaction of graphene with a nitrogen-fluorine mixture at 2 bars pressure. The fluorine content was simply controlled by varying the reaction time and temperature. The studies revealed that electron transfer kinetics and electrocatalytic activity of CFx strongly depend on the degree of fluorination. The versatility of fluorinated graphene as a biosensor platform was demonstrated by cyclic voltammetry for different biomolecules essential in physiological processes, i.e. NADH, ascorbic acid and dopamine. Importantly, the highest electrochemical performance, even higher than pristine graphene, was obtained for fluorinated graphene with the lowest fluorine content (CF0.084) due to its high conductivity and enhanced adsorption properties combining π-π stacking interaction with graphene regions with hydrogen-bonding interaction with fluorine atoms.

Electrochemical Fluorographane: Hybrid Electrocatalysis of Biomarkers, Hydrogen Evolution, and Oxygen Reduction.

Fluorographane (C1 Hx F1-x+δ )n is a new member of the graphene family that exhibits hydrophobicity and a large band gap that is tunable based on the level of fluorination. Herein, sensing and energy applications of fluorographane are reported. The results reveal that the carbon-to-fluoride ratio of fluorographane has a great impact on the electrochemical performance of the materials. Lowered oxidation potentials for ascorbic and uric acids, in addition to a catalytic effect for hydroquinone and dopamine redox processes, are obtained with a high fluoride content. Moreover, fluorographane, together with residual copper- and nickel-based doping, acted as a hybrid electrocatalyst to promote hydrogen evolution and oxygen reduction reactions with considerably lower onset potentials than those of graphane (starting material), which makes this a promising material for a broad range of applications.

Tuning of fluorine content in graphene: towards large-scale production of stoichiometric fluorographene.

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.

Fluorographane (C1H(x)F(1-x-δ))n: synthesis and properties.

Fluorographane (C1HxF1-x-δ)n was obtained from graphene by hydrogenation via the Birch reaction with consequent fluorination of the resulting graphane. Fluorographane exhibits fast heterogeneous electron transfer rates and hydrophobicity, which increase with increasing fluorination.