The formation of PTCDI-based metal organic structures on a Au(111) surface modified by 2-D Ni clusters

The adsorption of PTCDI (3,4,9,10-perylene-tetracarboxylic diimide) onto a Au(111) surface templated by two-dimensional (2-D) Ni clusters has been investigated by scanning tunneling microscopy (STM). We found that the nickel coverage has a significant effect on the distribution and stability of the characteristic hydrogen bonding phase of PTCDI and that a range of novel PTCDI-based aggregates can occur. Porous metal organic frameworks can be generated from diffusion of nickel from 2-D clusters. Close-packed Ni-PTCDI structures can result from incorporation of nickel into domains of the hydrogen bonding phase or rearrangement of porous frameworks after annealing treatments. Annealing Ni/Au(111) surfaces of low PTCDI coverage to higher temperatures leads to the formation of one-dimensional (1-D) molecular chains. We discuss the likely composition of the observed structures and the key role that nickel plays in their stabilization.