Theoretical possibility of the stable high spin multiple states in the boron-carbon layered systems

The possibility of the high spin stable states in the Boron-Carbon layered network systems have theoretically investigated through several BC 6MR polyacene clusters. The HF/6-31G^** calculations reveal that the alternant BC-benzene gives a quarter stable state rather than a doublet one, while a doublet state is more stable for the non-alternant BC-benzenes. Similarly, alternant BC-naphthalene gives a high-spin stable state (sextet) rather than lower ones (doublet, or quartet). These features are well understood by extending the Longuet-Higgins theory to this BC system.