Properties of Penta-tert-butylcorannulene Molecules Inserted in Phthalocyanine Networks Studied by Low-Temperature Scanning Tunneling Microscopy

Abstract

Octachloro zinc phthalocyanine networks on Ag(111) have been used as host structures for the insertion of penta-tert-butylcorannulene (PTBC) molecules. At ambient temperature, the resulting coassemblies generally present lines or chessboard structures, depending on the PTBC coverage. In this paper, it is shown that the annealing of these structures leads to the formation of novel networks in which the interplay of both molecules plays a major role. The presence of PTBC is also found to prevent the phase transition that generally appears in the phthalocyanine host lattices. PTBC molecules show two different positions with respect to the phthalocyanine networks when the observations are conducted at 4.6 K while at liquid nitrogen temperature (77 K), some of them appear with six bump features. Calculations suggest that this originates from the rotation barriers of the PTBC molecules in the host molecular structures. Finally, evaporation of the PTBC on a cooled substrate shows that the PTBC adsorbs on top of the Zn atom of the phthalocyanine and presents a nonuniform contrast due to the peculiar geometry of the PTBC/phthalocyanine structure.