Structures and energies are calculated at the DFTB level for C36-based fullerenes, hydrides, oligomers and solids. The two fullerenes with minimal pentagon adjacencies are isoenergetic. The isomer implicated in recent experiments has C6v broken symmetry, a small HOMO-LUMO gap and can gain or lose up to six electrons. C36 forms stronger inter-cage bonds than larger fullerenes. A favoured σ-bonding pattern rationalises a dimer with ten times the stabilisation of (C60)2, a linear polymer, a 'superbenzene' oligomer, a 'supergraphite' layer and a hexagonal close-packed solid with a monomer stabilisation of 522 kJ mol-1 and a d-spacing (6.82 Å) compatible with the experiments.
Bibliographical noteFunding Information:
We acknowledge financial support of this work by EPSRC (UK), DFG (Germany), DAAD/British Council (ARC 868), and the TMR initiative of the EU under contract FMRX-CT97-0126 on Usable Fullerene Derivatives. We also thank D.R. Salahub, A.M. Köster, V.G. Malkin and O.L. Malkina for their support with the DFT and deMon-NMR program packages. The computations were performed at the University of Exeter and Technische Universität Dresden.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry