Tertiary amide chemistry at the Ge(1 0 0)-2 × 1 surface

We have investigated the adsorption of several tertiary amides, including N,N-dimethylformamide, N,N-dimethylformamide-d7, 1-methyl-2-pyrrolidinone, and N-methylcaprolactam, on Ge(1 0 0)-2 × 1 using multiple internal reflection Fourier transform infrared spectroscopy and density functional theory. At 310 K, all four tertiary amides were observed to selectively form a dative bond to the germanium surface through the oxygen atom. While previous work has shown that oxygen dative bonds are unstable near room temperature, tertiary amides exhibit delocalization of electron density from nitrogen to oxygen, which appears to increase the stability of the oxygen dative-bonded state. Partial desorption of these surface adducts on the timescale of minutes indicates weakly bound surface adducts with coverage dependent binding energies.