Two-dimensional assembly of magnetic binuclear complexes: a scanning tunneling microscopy study.

Mono- and binuclear metal-organic compounds bearing long alkyl chains were synthesized and studied at the liquid/graphite interface using scanning tunneling microscopy. Two different lamellar surface patterns as well as a star like structure were obtained driven by van der Waals interactions of the alkyl chains and weak hydrogen bonds of the phenoxy moieties. In the case of the star like structure solvent molecules (1,2,4-trichlorobenzene) are supposed to play an important role for the stabilization of the created pattern. Magnetic investigation of the bulk material by a superconducting quantum interference device magnetometer revealed magnetic moments up to 1.7 mu(B) (NiCo) and most likely antiferromagnetic coupling between the two metals within a single complex. The presented two-dimensional crystallization of the binuclear complexes may provide an easy access to new designable materials in molecular electronics.