Reaction of isocyanates and isothiocyanates at the Ge(100)-2x1 surface

COLL 348

Paul W. Loscutoff, loscy@stanford.edu and Stacey F. Bent, bent@stanford.edu. Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford University, Stanford, CA 94305
Recently, multiple layer deposition of organic molecules was demonstrated using the highly reactive isocyanate moiety. Continuing this work, we have studied the reactions of several isocyanates and isothiocyanates on the Ge(100)-2x1 surface using multiple internal reflection Fourier transform infrared spectroscopy. Results for phenyl isocyanate indicate that the molecule adsorbs as a [2+2] reaction product between the C=N of the isocyanate group and the Ge surface dimer, in agreement with the published reaction product for 1,4-phenylene diisocyanate. Adsorption studies of mono-isothiocyanates suggest the presence of a sulfur dative-bonded state as well as a cycloaddition product between the isothiocyanate group and the Ge dimer. The adsorption product for 1,4-phenylene diisothiocyanate is difficult to characterize, but appears to differ from the reaction product for 1,4-phenylene diisocyanate. Nonetheless, the spectra show that there is an intact isothiocyanate moiety present in the adsorbed product, indicating the potential for a multiple layer reaction scheme.
 

Advanced Vibrational Spectroscopy Studies on Organic, Polymer, and Biological Surfaces
6:00 PM-8:00 PM, Monday, 11 September 2006 Moscone Center -- Room 104, Poster

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006