1. Laser photodissociation caused C60 to lose C2 fragments sequentially down to C32 at which time point C32 exploded into atoms and small non-fullerene Cn species Rice Group

3. Instead of C32

4. Polaroid image of the first molecular model of C28
HWK Nature, 329, (1987)

5. MS (Rice/Sussex unpublished result 1985)

6. Prediction
C28 tetravalent and should be stabilised by addition of four H atoms
HK Nature 1987

7. Prediction:
because strain released and four C6 aromatic rings remain
HK Nature 1987

8. Giant tetravalent “Superatom”
H W Kroto, Nature, 329, (1987)

9. FT-ICR-MS of Titanium Carbon Clusters
Firing the laser at lower He pressure but still condtions to see fullerenes and rings…good conditions to investigate the rings to fullerene crossover region (C22-C30 or so). Approximate 50 mDa mass difference between and empty cage C32.
All spectra show POSITIVE IONS.
FT-ICR-MS of Titanium Carbon Clusters 9

10. Ti with Paul Dunk and Alan Marshall
At FSU we decided to investigate the creation and properties of C28 in detail starting with Ti
with Paul Dunk and Alan Marshall

11. U

12. Laser vaporization of a UO2-graphite target
Laser vaporization of a UO2-graphite target
laser fired at different points in time along the pulse pressure profile
is clearly seen to form before larger
species

14. C28

16. C28 C32 C50 C60 C70 Predicted stable and semi-stable Fullerenes
image at:

17. Exxon Data
Cox et al
JACS
1588 (1988) NB
No C22 possible!

18. FT-ICR-MS Titanium Carbon Clusters
Only Cn n even clusters
Ti mass 48 = 4x12
C27
C28
C23
C26
C31
C24
C25
C30
C29
C22
Firing the laser at lower He pressure but still condtions to see fullerenes and rings…good conditions to investigate the rings to fullerene crossover region (C22-C30 or so). Approximate 50 mDa mass difference between and empty cage C32.
All spectra show POSITIVE IONS.
FT-ICR-MS Titanium Carbon Clusters

19. The detection of U@C28 confirmed that C28 is tetravalent and stabilised endohedrally
Rice group 1993

20. Ti@C28 observed when the pure C28 is not detectedCn
Intensities for high pressure conditions, again only even clusters(fullerenes). beginning at with a special abundance for
Clearly shows the stabilizing effect of the endohedral titanium atom…C26, C28, C30 do not form as the bare cages.

21. Molecular and Schlegel representations of Ti@Td-C28
Molecular and Schlegel representations of The internally located Ti atom is located off center, yielding additional stabilization.

22. Zr

23. Laser vaporization of a rod UO2 (0.8 atom %)
graphite enriched with 13C amorphous carbon 10 atom %
incorporates all enriched 13C

24. The main isotope of Ti
has mass 48 amu
…so mass C32 ~

25. Cn
Intensities for high pressure conditions, again only even clusters(fullerenes). beginning at with a special abundance for
Clearly shows the stabilizing effect of the endohedral titanium atom…C26, C28, C30 do not form as the bare cages.
no C28 25

26. Cn
Intensities for high pressure conditions, again only even clusters(fullerenes). beginning at with a special abundance for
Clearly shows the stabilizing effect of the endohedral titanium atom…C26, C28, C30 do not form as the bare cages. 26

27. FT-ICR-MS of Titanium Carbon Clusters
Firing the laser at lower He pressure but still condtions to see fullerenes and rings…good conditions to investigate the rings to fullerene crossover region (C22-C30 or so). Approximate 50 mDa mass difference between and empty cage C32.
All spectra show POSITIVE IONS.
FT-ICR-MS of Titanium Carbon Clusters 27

28. FT-ICR-MS of Titanium Carbon Clusters
Endohedral
fullerenes even only
n = 32 34 36 38
Firing the laser at lower He pressure but still condtions to see fullerenes and rings…good conditions to investigate the rings to fullerene crossover region (C22-C30 or so). Approximate 50 mDa mass difference between and empty cage C32.
All spectra show POSITIVE IONS.
FT-ICR-MS of Titanium Carbon Clusters

29. Electrostatic potentials
neutral C28
C284-
Electrostatic potentials
Charge is transferred from Ti and localized at the four pyramidalised carbon atoms (with Poblet)

30. Rice Group showed that under intense laser irradiation C60 lost C2 fragments sequentially and at C32 blew up completely into small carbon species and atoms
C60 → C58 → C56 → → → → C32 →
C C C Cn (n small)

31. I decided to play with a molecular model kit to see what the C32 structure might be – just like a kid again

32. I decided to play with molecular model kit to see what C32 structure might be

34. Endohedral Fullerenes can satisfy “valencies” internally
at: commons.wikimedia.org/wiki/File:Endohedral_fu...

35. U@C28 is also a highly favored species.

36. Electrostatic potentials
neutral C28
Electrostatic potentials
Negative charge is transferred from Ti and localized at the four pyramidalised carbon atoms

37. FT-ICR-MS of Titanium Carbon Clusters
Firing the laser at lower He pressure but still condtions to see fullerenes and rings…good conditions to investigate the rings to fullerene crossover region (C22-C30 or so). Approximate 50 mDa mass difference between and empty cage C32.
All spectra show POSITIVE IONS.
FT-ICR-MS of Titanium Carbon Clusters 37

38. Zr@C28 is not as favored as Ti@C28.
is the smallest endohedral fullerene formed C32 is the smallest empty cage.
is not as favored as

39. The structure proposed for C28 contains four triple fused pentagons units arranged in tetrahedral symmetry.

40. Sussex NNC

41. Sussex NNC

42. ~sp3
Sussex NNC

43. Four Benzenoid aromatic rings remain

44. C44
C28 Cn
Intensities for high pressure conditions, again only even clusters(fullerenes). beginning at with a special abundance for
Clearly shows the stabilizing effect of the endohedral titanium atom…C26, C28, C30 do not form as the bare cages. 44

45. Cn
distribution (Red) vs. empty cage distribution (Blue)
Clearly shows titanium stabilizes C28 and other small fullerenes.