Structure of monolayers of short chain n-alkanoic acid (CH[sub 3](CH[sub 2])[sub n]COOH, n = 0-9) spontaneously adsorbed from the gas phase at silver as probed by infrared reflection spectroscopy

Journal Article · Thu Jul 29 04:00:00 EDT 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100132a037· OSTI ID:6028413

Smith, E L; Porter, M D ^[1]

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1. Iowa State Univ., Ames (United States)

This paper presents the results of an infrared spectroscopic and wettability examination of monolayers formed by the spontaneous adsorption of short chain n-alkanoic acids (CH[sub 3](CH[sub 2])[sub n]COOH, n = 0-9) from the gas phase onto Ag. The infrared spectral data, collected in an external reflection mode, indicate that the monolayers chemisorb as the corresponding salt and that the chains contain all-trans conformational sequences for n = 1-9. The chemisorption process is further exemplified by the formation of a carboxylate group that is symmetrically bound at Ag as either a bidentate or bridging ligand. The conformational insights are developed on the basis of an unusually prominent series of the methylene wagging progression. An in-depth analysis resulted in the complete assignment of the fundamental modes in the progression as well as a reassignment of the CC stretch in the region of this progression. Structural insights developed from the infrared spectral data and contact angle measurements are compared to analogous monolayers formed from dilute solution. This comparison points to the subtle, but important, role of solvent in influencing the structure of the monolayer. 48 refs., 8 figs., 1 tab.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6028413
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:30; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ADSORPTION
CARBOXYLIC ACIDS
DATA
ELEMENTS
EXPERIMENTAL DATA
FILMS
FLUIDS
GASES
INFORMATION
INFRARED SPECTRA
LIGANDS
METALS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
SILVER
SORPTION
SPECTRA
TRANSITION ELEMENTS
VAPORS
WETTABILITY