C36, a hexavalent building block for fullerene compounds and solids

Fullerene Dimers Connected through C24and C36Bridge Cages

“…As the structures are being reported for the first time, their geometrical characteristics are discussed briefly with the aim of giving better interpretations of these clusters. Based on the optimized structures, the intercage bond lengths of six fullerene dimer are in the range 1.603-1.622 Å, which can be compared with the intercage bond lengths of 1.60 Å reported by Fowler et al 47 for a linear chain of D 6h -C 36 cages, and the electron-diffraction pattern of C 36 -based solid which suggested an intercage distance shorter than 1.7 Å. Moreover, the calculated C-C bond lengths of 1.657-1.660 Å in the two hexagonal terminal caps of C 24 bridge cages are slightly longer than the corresponding C-C bond lengths (1.522-1.604 Å) in the C 36 bridge cages.…”

Cool Cluster Correctly Correlated

“…But since the synthesis of fullerenes takes place at high temperature, the entropy contribution can be quite significant. Slanina et al [3], using a hybrid HJ?/DFT method, showed that even though the D2d isomer is the most stable one at 0 K, the D6h isomer becomes the most stable isomer at temperatures higher than -500 K. The other explanation is based on the exceptionally large electron correlation energy in the D6h isomer [13,14] predicted by a semi-empirical method. Fowler et al [13 J used configuration interaction (CI) calculations, including single and double excitations in the space of the four orbitals (HOMO-1, HOMO, LUMO and LUMO+l), to show that the eIectron correlation effect is significantly larger for the D6h isomer compared to other C36 isomers.…”

“…Interestingly, several authors suggest that the D6h isomer undergoes a second-order Jsthn-Teller distortion which reduces the symmetry of this isomer from D6h to c 6 v or even to C2h symmetry [3,13]. Others argued that at least according to hybrid HF/DFT, such a distortion does not occur [7,9].…”

13C NMR patterns of C36H2x fullerene hydrides

“…Simple H€ u uckel theory predicts a pseudo-closed shell p configuration with a non-zero HOMO-LUMO gap for 36:14. In the case of 36:15, it predicts a zero-gap open shell p configuration, which is converted to a closed shell by a second-order Jahn-Teller effect, which leads to a reduction of symmetry to C 6v [4] or C 2v [5]. 36:14 and 36:15 cages are predicted to be essentially isoenergetic in density-functional based methods [5,6], while Hartree-Fock (HF) and HF based semi-empirical Hamiltonians find 36:14 to be more stable than 36:15 [4,7] by [5].…”

“…In the case of 36:15, it predicts a zero-gap open shell p configuration, which is converted to a closed shell by a second-order Jahn-Teller effect, which leads to a reduction of symmetry to C 6v [4] or C 2v [5]. 36:14 and 36:15 cages are predicted to be essentially isoenergetic in density-functional based methods [5,6], while Hartree-Fock (HF) and HF based semi-empirical Hamiltonians find 36:14 to be more stable than 36:15 [4,7] by [5]. In most of the ensuing theoretical work on solid C 36 , the 36:15 isomer was taken as the building block [4,[8][9][10][11].…”