The interaction of aromatic molecules with nickel

The bonding and reactivity of benzene, and methyl, amino and cyano substituted benzenes have been examined on Ni(100) and Ni(111). Benzene is more strongly adsorbed on Ni(100) due to greater overlap between the carbon p-orbitals and the Ni d-orbitals. Methyl groups weaken the bonding to the surface by altering the symmetry of the bonding molecular orbitals. An amino group enhances electrophilic substitution reactions leading to surface polymerization. Cyano groups withdraw electrons from the aromatic ring, reducing the interaction of the ring with the surface. The behavior is explained in terms of electrophilic reactions with the surface acting as an electrophile.