Inelastic light scattering of hydrogen containing open‐cage fullerene ATOCF

Abstract

1 Introduction Endohedral complexes incorporating noble gases and other atomic species have attracted recent scientific interest in fullerene [1] and nanotube research [2]. They offer the possibility of studying quasi-isolated species inside the C 60 cage and, e.g., using them as contrast agent in magnetic resonance imaging.Transformation of the σ framework of the fullerene cage causing an opening of a sufficiently large orifice by organic synthesis can greatly improve the yields of endohedral fullerenes. The C 60 derivative Aza-Thia Open-Cage Fullerene has a 13-membered-ring orifice [3] on the C 60 cage with dimensions 5.64 × 3.75 Å 2 and is expected to have good hosting properties for small atoms and molecules like H 2 and He. It was shown recently that the encapsulation of an H 2 -molecule in ATOCF creates with very high yield the endohedral complex H 2 @ATOCF [4]. In this work we examine H 2 @ATOCF and the empty ATOCF by means of Raman spectroscopy. We establish significant differences in the Raman response of open-cage

Infrared spectroscopy of small-molecule endofullerenes

“…The translational and rotational energies of H 2 @C 60 and HD@C 60 in the v = 0 state determined by IR spectroscopy are consistent with the low-temperature INS results [35]. There are no Raman data on H 2 @C 60 , except a report on H 2 inside an open-cage fullerene [36].…”

Cryogenic NMR spectroscopy of endohedral hydrogen-fullerene complexes

“…A hydrogen molecule trapped inside the fullerene cavity has six spatial degrees of freedom-three translational, two rotational, and one vibrational-as well as the nuclear spin degrees of freedom. In the following discussion, the endohedral H 2 molecules are assumed to be in the ground vibrational state ͑ =0͒ over the experimental temperature range, since the vibrational splitting is ប vib / k B Х 5950 K, 23 close to that expected for free hydrogen gas. The spatial state of a confined H 2 molecule may therefore be indexed by five quantum numbers, and is denoted ͉Jm J n ᐉ m ᐉ ͘, where ͕J , m J ͖ are the rotational quantum numbers and ͕n , ᐉ , m ᐉ ͖ are the translational quantum numbers.…”

Rotor in a cage: Infrared spectroscopy of an endohedral hydrogen-fullerene complex

“…Moreover, there is very little experimental information on the quantum dynamics of H 2 in fullerene cages. [10][11][12][13] In general, isolated homonuclear diatomics have no infrared ͑IR͒ activity. 14 However, H 2 does display IR activity in situations where there are intermolecular interactions present, such as in the solid and liquid phases, 15,16 in constrained environments, [17][18][19][20] and in pressurized gasses.…”

“…Theoretically it has been shown that in C 60 cages the quantum rotors CO [7] and H 2 [8,9] should have a measurable translation-rotation coupling, a feature that has not been experimentally resolved to our knowledge. Moreover, there is very little experimental information on the quantum dynamics of H 2 in fullerene cages [10,11,12,13].…”