title: Self-assembled monolayers of NH2-terminated thiolates: order, pKa, and specific adsorption.
abstract: Self-assembled monolayers (SAMs) of amino-terminated alkanethiols on Au were characterized by a combination of electrochemical (LSV, CV, and EIS) and spectroscopic (XPS and SER) techniques. Clear correlations were obtained between the apparent surface pKa values determined by impedimetric titrations and order parameters such as the content of trans conformers in the SAMs. These results contrast with previous studies that exhibit dispersions of up to 6 pH units in the reported pKa values. In addition, we determined that inorganic and organic phosphate species bind specifically to these SAMs mediating adsorption and heterogeneous electron transfer of positively charged macromolecules such as cytochrome c.
authors.affiliation: Departamento de Química Inorgánica, Analítica y Química Física and INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and CONICET, Ciudad Universitaria, pab. 2, piso 3, C1428EHA-Buenos Aires, Argentina.
authors.forename: Waldemar A
authors.initials: WA
authors.lastname: Marmisollé
authors.forename: Daiana A
authors.initials: DA
authors.lastname: Capdevila
authors.forename: Ezequiel
authors.initials: E
authors.lastname: de la Llave
authors.forename: Federico J
authors.initials: FJ
authors.lastname: Williams
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Murgida
mesh_terms: D000327:Adsorption; D000473:Alkanes / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000473:Alkanes; D013438:Sulfhydryl Compounds; D006046:Gold; D045304:Cytochromes c