title: Hydrogen bonding vs. molecule-surface interactions in 2D self-assembly of [C60]fullerenecarboxylic acids.
abstract: The adsorption of C60-malonic derivatives C61(CO2H)2and C66(CO2H)12on Au(111) and a pentafluorobenzenethiol-modified Au substrate (PFBT@Au) has been investigated using scanning tunneling microscopy (STM) at a liquid-solid interface. Monofunctionalized C61(CO2H)2forms a hexagonal close-packed overlayer on Au(111) and individual aligned dimers on PFBT@Au(111). The difference is attributed to the nature of the substrateC61(CO2H)2interaction (isotropic π-Au bonding vs. anisotropic PFBTCOOH interactions). Surprisingly, in both cases, the directionality of the COOHCOOH motif is compromised in favor of synergistic van der Waals/H bonding interactions. Such van der Waals contacts are geometrically unfeasible in hexafunctionalized C66(CO2H)12and its assembly on Au(111) leads to a 2D molecular network controlled exclusively by H bonding. For both molecules, the "free" CO2H groups on the monolayer surface can engage in out-of-plane H bonding interaction resulting in the epitaxial growth of subsequent molecular layers.
authors.affiliation: Department of Chemistry and Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada. Bruce.Lennox@mcgill.ca Dmitrii.Perepichka@mcgill.ca.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Mezour
authors.affiliation: Department of Chemistry and Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada. Bruce.Lennox@mcgill.ca Dmitrii.Perepichka@mcgill.ca.
authors.forename: Rachelle M
authors.initials: RM
authors.lastname: Choueiri
authors.affiliation: Department of Chemistry and Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada. Bruce.Lennox@mcgill.ca Dmitrii.Perepichka@mcgill.ca.
authors.forename: Olena
authors.initials: O
authors.lastname: Lukoyanova
authors.affiliation: Department of Chemistry and Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada. Bruce.Lennox@mcgill.ca Dmitrii.Perepichka@mcgill.ca.
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Lennox
authors.affiliation: Department of Chemistry and Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, QC H3A 0B8, Canada. Bruce.Lennox@mcgill.ca Dmitrii.Perepichka@mcgill.ca.
authors.forename: Dmitrii F
authors.initials: DF
authors.lastname: Perepichka