Preparation of hydrofullerenes by hydrogen radical induced hydrogenation

The Synthesis and Characterization of Fullerene Hydrides

“…However, in reviewing these results in another report on the 1 H spectra of isomers of C 60 H 4 , Billups and co-workers proposed alternative explanations, including residual anisotropic dipoleϪdipole interactions, for the origins of these extra signals. [43b] C 60 can also be reduced with anhydrous hydrazine in benzene to give a mixture of fullerene hydrides C 60 H n (n ϭ 2, 4,6,8,18,36). [12] The relative ratio of the different hydrides was similar to that obtained by the Cu 2ϩ -catalyzed diimide reduction employed by Avent, [7] and the yield of the more reduced fullerenes could be improved by increasing the molar excess of anhydrous hydrazine.…”

“…[27a] The fullerene hydrides are significantly less soluble than the parent fullerenes in common solvents, and in some cases this has presented a major obstacle to the isolation of samples suitable for spectral characterization. [8,9,28] Carbon disulfide is frequently used, [7] although the more highly reduced hydrides have been observed to form insoluble precipitates upon dissolution in carbon disulfide. [27] Although chemical shifts are found to be solvent-dependent, [7] NMR spectra of the lower hydrides can be obtained readily.…”

“…[10] Acceptable EI-MS spectra of C 60 , C 70 , C 76 , C 78 , and C 84 hydrides have been obtained immediately after workup through use of carefully prepared samples. [27,29Ϫ31] FAB has been successfully used as a mild MS ionization technique by some workers, [8,13] but others have observed a range of hydrides below the M ϩ peak and additional lines appearing at higher masses as well, [10] a phenomenon that prevented definitive analysis of the hydrides resulting from reduction of C 60 by diimide. [7] Rüchardt and Lobach and their co-workers have each reported field desorption mass spectrometry as a preferred method.…”

“…[10,29] It has also been reported that mass spectra obtained by laser desorption ionization reveal weak M ϩ peaks along with a range of partially dehydrogenated products. [8,10,32] Ballenweg and co-workers used LD-TOF mass spectrometry to characterize C 60 H 2 , [9] but fragmentation was presumably a minor problem with the dihydrofullerene. Banks and co-workers cited LD-TOF data in support of their contention that the principal product of the C 60 Birch reduction was actually C 60 H 32 and not C 60 H 36 [33] as originally reported.…”

Gas phase fullerene anions hydrogenation by methanol followed by IRMPA dehydrogenation

“…To our knowledge, the only reported successful hydrogenation of an azafullerene using a mass spectrometer was by Drewello and coworkers [14]. The synthetic approaches reported and leading to the formation of fullerene hydrides include the Birch reduction [11,15,16], the Benkeser reduction [17], polyamine reduction [18,19], reduction by diimides [20], hydroboration [21,22], hydrogen transfer reduction [7,11,23,24], photoreduction [25], transition-metal catalyzed hydrogenation [26 -28], zincconcentrated hydrochloric acid reduction [9,29,30], Zn(Cu) reduction [31][32][33], hydrozirconation [34], hydrogen radical induced hydrogenation [35], electrochemical reduction [36 -38], sonication [39], direct reduction by hydrogen [27, 40 -43], and direct exposure to atomic hydrogen [44,45]. Typically involving extreme conditions, with temperatures of several hundred Kelvin, pressures about several mega Pascal, or condensed phase condition [7,15,21,22,46], they significantly differ from the hydrogenation conditions used here and leading to the addition of up to 11 H…”