Gas phase fullerene anions hydrogenation by methanol followed by IRMPA dehydrogenation

Abstract

The characterization in the gas phase of the mechanisms responsible for hydride formation can contribute to the development of new materials for hydrogen storage. The present work provides evidence of a hydrogenation-dehydrogenation catalytic cycle for C 60•Ϫ anions in the gas phase using methanol vapor at room temperature as hydrogen donor. The involvement of methanol in the reaction is confirmed by experiments using CD 3 OD and CD 3 OH. C 60 hydride anions with up to 11 hydrogen atoms are identified via elemental composition analysis using FT-ICR mass spectrometry. For the longer reaction times, partial conversion of the C 60 hydride ions into oxygen containing ion products occurs. Dehydrogenation using infrared multiphoton activation with a CO 2 laser restores the C 60•Ϫ anions. (J Am Soc Mass Spectrom 2010, 21, 117-126)

Formation of Singly Bonded Fullerene Dimers in Electrospray Mass Spectrometry

“…While the aprotic solvents DCM and ACN apparently do not influence the radical reaction, MeOH has been shown to transfer hydrogen atoms to fullerene radicals in the gas phase. 25 MeOH could therefore react with the radical C 60 (12cr4 − H)K +• , restoring 26 By intentionally adding a radical scavenger to the sample solution, they successfully verified the involvement of radicals in the reaction mechanism. We tried the same approach with the crown ether C 60 adducts, adding hydroquinone to the sample solution (DCM/ACN) and monitoring the change in relative abundance of the two dimeric species.…”

“…While the aprotic solvents DCM and ACN apparently do not influence the radical reaction, MeOH has been shown to transfer hydrogen atoms to fullerene radicals in the gas phase. 25 MeOH could therefore react with the radical C 60 (12cr4 − H)K +• , restoring the intact crown ether fullerene, C 60 H(12cr4 − H)K + , and preventing further reaction to the covalently bound dimer. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 MeOH without hydroquinone.…”

“…A radical mechanism would explain the dependency on the solvent mixture. While the aprotic solvents DCM and ACN apparently do not influence the radical reaction, MeOH has been shown to transfer hydrogen atoms to fullerene radicals in the gas phase . MeOH could therefore react with the radical C 60 (12cr4 – H)­K +• , restoring the intact crown ether fullerene, C 60 H­(12cr4 – H)­K + , and preventing further reaction to the covalently bound dimer…”

Fullerenes

“…Hydrogenation, dehydrogenation studies taking place in the gas phase can help elucidate mechanisms taking place in other media and pertaining to hydrogen storage or direct methanol fuel cell applications. 34 2.1.4 Polymerisation. The mechanism of the addition reaction of PCHD carbanion to C 60 was examined using PCHDLi, PCHDLi/DABCO, and PCHDLi/TMEDA.…”