Formation of an organometallic junction by direct bonding of 4-nitrobenzene monolayer on gold surface by diazonium chemistry has been demonstrated by Fourier transform reflection-absorption spectroscopy with s- and p-polarized radiation.

A detailed polarization modulation infrared reflection absorption spectroscopy, scanning tunneling microscopy, and electrochemical study on methylene blue (MB) incorporation into alkanethiolate self-assembled monolayers (SAMs) on Au(111) is reported. Results show that the amount of MB incorporated in the SAMs reaches a maximum for intermediate hydrocarbon chain lengths (C10-C12). Well-ordered SAMs of long alkanethiols (C > C12) hinder the incorporation of the MB molecules into the SAM. On the other hand, less ordered SAMs of short alkanethiols (C < or = C6) are not efficient to retain the MB incorporated through the defects. For C12 the amount of incorporated MB increases as the SAM disorder is increased. This information is essential to the design of efficient thiol-based Au vectors for transport and delivery of molecules as well as thiol-based Au devices for molecular sensing.

Chemically modified electrodes by the osmium complex Os bpy ð Þ 2 Clpy À X Â Ã þ PF À 6 tethered to Au surfaces by (1) reaction of cysteamine with the aldehyde (X=CHO), (2) mercapto alkanoic acid reaction with amine [X= (CH 2 ) 2 NH 2 ], and (3) reduction of the diazonium salt of paminobenzoic acid and further amidation reaction with the amine derivative of the osmium complex [X=(CH 2 ) 2 NH 2 ] were performed to explore the electron transfer properties of these redox-modified surfaces. The modified Au surfaces were characterized by infrared reflection absorption spectroscopy and resonant Raman spectroscopy. Cyclic voltammetry was used to study the electrochemical properties of the osmium complexes covalently attached to the surface as a function of the type and length of the tether.