The adsorption and self-assembly of Gd@C-82 molecules on Cu(100) surface have been investigated using scanning tunneling microscopy (STM). The metallofullerene molecules in the assemblies showed two characteristic apparent heights in the STM images. STM manipulation and spectroscopy was performed and revealed the formation of Cu adatom islands underneath the Gd@C-82 molecules. The monolayered Cu aggregates were resulted from the adatom-molecule complexation, which is supported by density functional theory (DFT) calculations that show charge transfer and electrostatic interactions between Gd@C-82 and adatoms. In addition, sub-molecularly resolved STM images demonstrated the structural and orientational ordering of Gd@C-82 assemblies upon thermal annealing. DFT calculations demonstrated that Gd atom located at the lower part of the carbon cage is a favored adsorption configuration for Gd@C-82 molecules adsorbed on Cu (100). (C) 2011 Elsevier B.V. All rights reserved.