Photochemical patterning of SAM by Wolff rearrangement: Evidence for “surface-isolated” carbonylcarbene

ORGN 234

Jun Hu, Yubiao Liu, and Chalermchai Khemtong. Department of Chemistry, The University of Akron, 190 E. Buchtel Comm, Akron, OH 44325-3601

Photolithographic attachment of functional organic molecules via ester or amide linkages to self-assembled monolayers (SAMs) on gold thin films was achieved by employing a novel photoreactive surface anchor, 7-diazomethylcarbonyl-2, 4, 9-trithiaadmantane. The photoreactive SAM was prepared by the spontaneous physical adsorption of the photoreactive surface anchor onto gold surfaces. The a-diazoketone moiety of the SAM was found to display the classical Wolff rearrangement reactivity to produce a ketene intermediate on the exposed area. Organic molecules such as alcohols and amines can thus be attached to the gold surfaces selectively by the facile in situ formation of ester or amide linkages. The structure and reactivity of the photoreactive surface anchor were characterized by real-time FT-IR, fluorescence and polarization modulation infrared reflectance absorption spectroscopy (PM-IRRAS). The Wolff rearrangement reactivity of the SAM suggested that a “surface-isolated” carbonylcarbene was generated when the SAM was exposed to 255 nm irradiation.

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