Systematic investigation of the stability of all dihydro isomers of the more stable C38 fullerene isomer with C2 symmetry

The local aromaticity of fullerene C-38 (C-2) was studied using the bond resonance energy (BRE) method. The global aromaticity of all 349 possible isomers of C38H2 based on C-2 symmetry was investigated using the topological resonance energy (TRE) method. The TRE results show that most of the C38H2 isomers have greater stability than C-38 (C-2). Based on the BRE results, the preferred addition sites of hydrogen atoms are discussed. The relationship between the addition sites and BREs is analyzed and discussed. We found that the addition sites of hydrogen atoms are strongly dependent on the magnitude of the parent cage BRE values. The most stable isomers of C38H2 are often produced by diminishing of the pi-bonds from those sites in the parent cage at which are located the two carbon atoms with the lowest BRE values. Based on this rule, the preferred addition patterns for non-IPR fullerene cages can be easily predicted.