HWK Nature, 329, 529 (1987) Polaroid image of the first molecular model of C 28 C 28

Mass Spectrum of Carbon Clusters Heath, Liu, O’Brien, Curl, Kroto and Smalley unpublished data C 28

Prediction C 28 tetravalent and should be stabilised by addition of four H atoms HK Nature 1987

Prediction: because strain released and four C 6 aromatic rings remain HK Nature 1987

C 28 should be a giant tetravalent “Superatom” H W K Nature, 329, 529 (1987)

Ti Properties of C 28 in detail starting with 28 with Paul Dunk and Alan Marshall

C U

NHMFL FSU Laser vaporization of a UO 2 -graphite target laser fired at different points in time along the pulse pressure profile 28 is clearly seen to form before larger n species 28

Exxon Data Cox et al JACS (1988)

C 32

Endohedral Fullerene Comparison Spectra

Delft Buckyball Wkshp Dynamic Z

WOW Moment

Nori Shinohara - Nagoya Alan Marshall Dr. FT-ICR-MS Chris Hendrickson Nathan Kaiser Paul Dunk

Rice Group showed that under intense laser irradiation C 60 lost C 2 fragments sequentially and at C 32 blew up completely into small carbon species and atoms C 60 → C 58 → C 56 → → → → C 32 → C 2 C 2 C 2 C n (n small)

C 28 should be special - a tetravalent “Superatom” atom H W Kroto, Nature, 329, 529 (1987) Polaroid image of the first molecular model of C 28

Mass spectrum of laser vapourised graphite (Rice 1985) C 28

Sussex NNC

~sp 3

Four Benzenoid aromatic rings remain

Exxon Data Cox et al JACS (1988) NB No C 22 possible!

Sussex NNC

The structure proposed for C 28 contains four triple fused pentagons units arranged in tetrahedral symmetry.

Predicted stable and semi-stable Fullerenes image at: C 28 C 32 C 50 C 60 C 70

Predicted stable and semi-stable Fullerenes image at: C 28 C 32 C 50 C 60 C 70

C 28 should be tetravalent

C 28 U

C 28 Ti

distribution (RED) vs. empty cage distribution (BLUE) for FIG (2). Clearly shows titanium has stabilized C 28, and other small fullerenes.

C 28 Sussex NNC

C 28 ”superatom” analogue of sp 3 carbon atom Suggests T d C 28 H 4 Nature (1987) C 28 H 4

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

Titanium Rod – Positive ions M(C 28 ) + M(Ti) = = 384 C 28 Ti Predicted

C 32 ca 50 milliDaltons separation Titanium Rod – Positive ions M(C 28 ) + M(Ti) = = 384 M(C 32 ) = 384

Titanium Rod – Positive ions C 28 Ti Predicted Minus C 32 mass peaks

FT-ICR-MS relative intensities of n vs n n Abundancerel units Paul Dunk with Harry Kroto and Alan Marshall n vs n

(T d ) C 28 more stable by 717 kJmol -1 than D 2 (T d ) 28 more stable by 270 kJmol -1 than D 2 David E. Bean, Patrick W. Fowler, University of Sheffield C 28 (D 2 )C 28 (T d )

image at:

C 28 ”superatom” analogue of sp 3 carbon atom Suggests T d C 28 H 4 Nature (1987) C 28 H 4

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

FT-ICR-MS relative intensities of n vs n n Abundancerel units Paul Dunk with Harry Kroto and Alan Marshall n vs n

(T d ) C 28 more stable by 717 kJmol -1 than D 2 (T d ) 28 more stable by 270 kJmol -1 than D 2 David E. Bean, Patrick W. Fowler, University of Sheffield C 28 (D 2 )C 28 (T d )

For the bare cages, the tetrahedral isomer is more stable by a.u. (717 kJmol-1). When a titanium atom is encapsulated, this gap decreases to a.u. (270 kJmol- 1), but the tetrahedral isomer remains the more stable. David E. Bean, Patrick W. Fowler, University of Sheffield C 28 (D 2 )C 28 (T d )

at: commons.wikimedia.org/wiki/File:Endohedral_fu... commons.wikimedia.org/wiki/File:Endohedral_fu...

image at: people.whitman.edu/~hoffman/people.whitman.edu/~hoffman/

Abundance of Endohedral Fullerenes n vs n

n Abundancerel units 28 38

Some of the more stable members of the fullerene family. (a) C28. (b) C32. (c) C50. (d) C60. (e) C70. image at:

Abundance of Endohedral Fullerenes n vs n n Abundancerel units 28 38

For the bare cages, the tetrahedral isomer is more stable by a.u. (717 kJmol-1). When a titanium atom is encapsulated, this gap decreases to a.u. (270 kJmol- 1), but the tetrahedral isomer remains the more stable. David E. Bean, Patrick W. Fowler, University of Sheffield C 28 (D 2 )C 28 (T d )