Binding of glycine and L-cysteine on Si(111)-7x7

作者：Huang, Jing Yan; Ning, Yue Sheng; Yong, Kian Soon; Cai, Ying Hui; Tang, Hai Hua; Shao, Yan Xia; Alshahateet, Solhe F.; Sun, Yue Ming; Xu, Guo Qin^*

来源：Langmuir, 2007, 23(11): 6218-6226.

DOI：10.1021/la700305b

• SCANNING-TUNNELING-MICROSCOPY
• X-RAY PHOTOELECTRON
• AMINO-ACIDS
• FORMIC-ACID
• DISSOCIATIVE ADSORPTION
• SEMICONDUCTOR SURFACES
• ELECTRON-DIFFRACTION
• ORGANIC-MOLECULES
• GASEOUS GLYCINE
• GOLD

The adsorption of glycine and L-cysteine on Si(111)-7x7 was investigated using high-resolution electron energy loss spectroscopy (HREELS) and X-ray photoelectron spectroscopy (XPS). The observation of the characteristic vibrational modes and electronic structures of NH3+ and COO- groups for physisorbed glycine (L-cysteine) demonstrates the formation of zwitterionic species in multilayers. For chemisorbed molecules, the appearance of nu(Si-H), nu(Si-O), and nu(C Omicron) and the absence of nu(O-H) clearly indicate that glycine and L-cysteine dissociate to produce monodentate carboxylate adducts on Si(111)-7x7. XPS results further verified the coexistence of two chemisorption states for each amino acid, corresponding to a Si-NH-CH2-COO-Si [Si-NHCH(CH2SH)COO-Si] species with new sigma-linkages of Si-N and Si-O, and a NH2-CH2-COO-Si [NH2CH(CH2SH)COO-Si] product through the cleavage of the O-H bond, respectively. Glycine/Si(111)-7x7 and L-cysteine/Si(111)-7x7 can be viewed as model systems for further modification of Si surfaces with biological molecules.

• 出版日期2007-5-22
• 单位东南大学