  Local reactivity descriptors such as the condensed local softness and Fukui
function have been employed to investigate the inter-cluster reactivity of the
metallo-aromatic (Al4Li- and Al4Na-) and anti-aromatic (Al4Li4 and Al4Na4)
compounds. We use the concept of group softness and group Fukui function to
study the strength of the nucleophilicity of the Al4 unit in these compounds.
Our analysis shows that the trend of nucleophilicity of the Al4 unit in the
above clusters is as follows;
  Al4Li- > Al4Na- > Al4Li4 > Al4Na 4
  For the first time we have used the reactivity descriptors to show that these
clusters can act as electron donating systems and thus can be used as a
molecular cathode.
