title: Building self-assembled molecular layers with axially substituted titanium phthalocyanines.
abstract: Adsorption on graphite (HOPG) by titanium phthalocyanine axially bonded to a catechol ligand (TiPcat), titanylphthalocyanine (TiOPc), and 1:1 mixtures of these are studied at the HOPG-octylbenzene interface. The surface structures of a two-component bilayer, and of the individual monolayers of TiOPc and TiPcat, were determined by scanning tunneling microscopy (STM). TiPcat self-segregates onto a monolayer of TiOPc when an equal molar mixture is used. The preferential formation of a TiOPc monolayer from a solution containing both molecules is attributed to the difference in adsorption energies between TiPcat and TiOPc on graphite. The transformation of the hexagonal lattice of the pure TiOPc monolayer into a pseudo-square lattice was induced by the adsorption of TiPcat molecules. DFT calculations of the catechol orientation are presented.
authors.affiliation: Department of Chemistry and Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164-4630, USA.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Takami
authors.forename: Aurora
authors.initials: A
authors.lastname: Clark
authors.forename: Richard
authors.initials: R
authors.lastname: Caldwell
authors.forename: Ursula
authors.initials: U
authors.lastname: Mazur
authors.forename: K W
authors.initials: KW
authors.lastname: Hipps