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The formation of the base pair adenine-uracil at a water−solid interface, at an immobilized monolayer of adenine disulfide with adenine groups exposed to the very surface, respectively, is shown here. To overcome the steric hindrance of tightly packed adenine groups in a pure adenine thiolate monolayer on gold, the formation of self-assembled monolayers out of a binary mixture of the adenine disulfide and CH3- or OH-terminated thiols are investigated. Electro-chemical investigations, surface plasmon spectroscopy (PSP, plasmon surface polariton), multimode waveguide-PSP-coupling spectroscopy, contact angle measurements, and spontaneous desorption time-of-flight mass spectrometry were used to characterize the monolayers. The specific base pairing was investigated for a variety of monolayer compositions. A specific base pairing was successful for an optimized mixed adenine/OH-terminated thiol monolayer. Nevertheless unspecific binding is a problem.

We demonstrate the area selective organometallic chemical vapor deposition (OMCVD) of ultrathin gold layers, using (trimethylphosphine)methylgold [(CH 3 ) 3 P]AuCH 3 as the gold source, onto self-assembled monolayers (SAMs) of x-functionalized, long chain alkanethiols on gold and silver coated silicon and mica samples. The dependence on the reaction time of surface coverage with gold nano-clusters is analyzed by atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) shows that nucleation and growth occur only on thiol functionalized surfaces and not on methyl or hydroxyl functionalized SAMs. The selectivity of the growth is completely lost if gold is deposited by thermal evaporation of the pure metal, as shown in direct comparison with the OMCVD method employing mixed SAMs of different surface reactivity (±SH vs. ±CH 3 ) that were patterned by microcontact printing.