Fullerene hydrides

In textbooks of fullerene chemistry, hydrogenation is the simplest reaction and fullerene hydrides are the simplest derivatives of fullerenes. Hydrogenation can be conducted under pressure and elevated temperatures. Heating at 400°C and 80 atm H yields red solid, [40]. Up to 48 H atoms can be added to under more forcing conditions. Catalytic hydrogenation at 280°C and 160 atm with use of Ru/C catalyst produce hydrofulerenes up to [41]. Hydrogenation is quite... 

Chen N, Klod S, Rapta P et al (2010) Direct Arc-discharge assisted synthesis of CeoH2(C3H5N) a cis-l-pyrrolino Ceo fullerene hydride with unusual redox properties. Chem Mater 22 2608-2615... 

Kharlamov AI, Kirillova NV (2009) Fullerenes and fullerenes hydrides as products of transformation (polycondensation) of aromatic hydrocarbons. Proc Ukr Acad Sci 5 112-120... 

Thermodynamic Properties of Fullerene Hydrides C60H2n and Equilibria of Their Reactions... 

Shortly after realization of preparative syntheses of fullerenes their high chemical activity was proved and fullerene hydrides were obtained (Goldshleger and Moravskii 1997). The methods of synthesis of fullerene hydrides have been intensively developing because these hydrides are considered to be the base compounds for the development of fullerene chemistry, possess a potential for the use as hydrogen accumulators. The... 

The synthesized fullerene hydrides vary both in the composition and in the isomeric structures. The number of possible isomers of the C60H2n fullerene hydrides varies over a wide range from 23 for C60H2 to >1015 for C60H30 (Balasubramanian 1991). In the synthesis, the mixtures are formed with a limited number of isomers due to thermodynamic and kinetic limitations. However, the synthesis of fullerene hydrides of high purity is still impossible due to the above mentioned peculiarities. The best samples correspond to the isomeric mixtures containing 1-5% of the hydrides of different formula. 

Thermal instability of fullerene hydrides makes additional difficulties for investigation of their physicochemical properties, especially at T> 400 K. 

The most effective way for investigation of thermodynamic properties for fullerene hydrides is a combination of the experimental methods, the quantum-chemical calculation of molecular characteristics, the statistical thermodynamic calculation of thermodynamic... 

In this Chapter the proposed approach is realized for thermodynamic investigation of the C60H2n fullerene hydrides. 

Isomerism of Cw II2n Fullerene Hydrides 4.2.1 Isomeric Composition of C60H2... 

Equations 4.2 and 4.3 are simplified for C60H2n because internal rotation does not occur in these molecules. As it was demonstrated for the C60 fullerene, the electronic contributions to its thermodynamic properties may be neglected at T < 1,000 K (Diky and Kabo 2000). The same is expected for fullerene hydrides. 

The formation enthalpies for gaseous fullerene hydrides were calculated above from quantum chemical calculations. Since the experimental sublimation enthalpies are available only for fullerene C60... 

Thermodynamic Properties of Fullerene Hydrides and Equilibria of Their Reactions 81 Table 4.13 Thermodynamic characteristics of reaction (4.16) with C cr)... 

Comprehensive investigation of thermodynamic properties for fullerene hydrides is actual for optimization of the conditions of their synthesis, chemical functionalization, justification of their technical application. The structure, spectra, isomeric compositions for the samples of fullerene hydrides seriously affect their thermodynamic properties. So, the thermodynamic investigations will favor solution of many theoretical problems of chemistry and physics of fullerene hydrides. Taking into account the difficulties in synthesis and separation of individual fullerene hydrides of high purity, one should suppose that the theoretical evaluation of their physicochemical properties is the most effective tool for their investigation. 

The conditions of syntheses of fullerene hydrides can be corrected with respect to dependence of equilibrium compositions on temperature and pressure (concentration). 

Fig. 10.13 FT-IR spectra in KBr of a mixture of fullerene hydrides C60Hx and C70Hy with x > 36-38...

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