| Over the past decades, there has been considerable interest in self-assembled monolayers (SAMs) of amphiphilic molecules. Self-assembled monolayers are ordered molecular assemblies that form spontaneously by the adsorption of a surfactant with a specific affinity of its headgroup to a specific substrate. Monolayer films can be prepared using two distinct methods: the Langmuir-Blodgett technique which involves the transfer of a film, preassembled at an air-water interface, to a solid substrate, and self-assembly which occurs spontaneously by immersion of the substrate into a solution containing an appropriate amphiphile. Most studies of self- assembled monolayers to date have been made on alkanethiol monolayers on gold surfaces because this system probably offers the best available combination of high structural order, flexibility in the structure of groups exposed at the extreme surface, and ease of preparation and analysis.These layers potentially enable to tailor and to optimize the surface properties for a variety of technological applications as well as for fundamental studies of surface phenomena. Physical and chemical properties of surfaces indeed influence many phenomena such as catalysis, corrosion, lubrication, adhesion, wettability, electrochemistry, biocompatibility, etc. All of these properties have resulted in the application of SAMs in many areas of science including microelectronics, biotechnology, materials science, protein interactions with organic surfaces, biochemical sensing, superlattices, chemical sensing, molecular recognition and lubricants.Porphyrin-based molecules used as a candidate for the fabricated center of SAMs have been extensively studied over recent years, primarily due to their importance in biological systems. Moreover, their versatile optical and electrochemical properties owing to porphyrins possess planar, rigid, aromatic, it-electron systems. The possibility to tune these properties by incorporating different metals into the center of the ring or by grafting various substituents at their peripheral positions, and their high chemical and thermal stabilities make porphyrins attractive materials in electronics, optoelectronics, and photonics. However, the attractive field has been progressed slowness since the difficulty of porphyrins and metalloporphyrins synthesis and separation.Accordingly, the emphasis of this thesis is placed on synthesizing under gentle condition the candidate for fabricated center of self-assembled monolayers: porphyrins(H2Por) and metalloporphyrins(MPor). The thesis is aimed at the SAMs of H2Por and MPor on gold electrode employing the traditional electrochemical methods such as cyclic voltammetry. Attempt has been made to investigation the interaction between electroactive species and the fabricated center of SAMs. At the same time, the thesis has been broaden the self-assembly technique of thiol-derivatized porphyrins on gold substrate. Consequently, the synthetic difficulty of thiol-derivatized porphyrins was reduced greatly.The main work of this thesis was described as following. The first part was reviewed the progress in porphyrins and self-assembled monolayers.Part II, The three new thiol-derivatized porphyrins 5-{3-methoxyl-4-(4-mercapto butyloxy)}phenyl-10,15,20-triphenylporphyrin(MBPP),5-{3-methoxyl-4-(4-mercaptohex yloxy)}phenyl-10,15,20-triphenylporphyrin(MHPP), 5-{3-methoxyl-4-(4-mercapto decadaloxy)}phenyl-10,15,20-triphenylporphyrin(MDPP) have been synthesized under acidic conditions by a modified process of Adler' preparation of the meso-tetraphenylporphin. The products have been characterized by IR, UV-Vis and !H NMR. The voltammetric behavior of gold electrodes modified with neutral free-base and positively charged cobaltous center porphyrin films were investigated using Fe(CN)63-/4-as probe species.In part III, a new thiol-derivatized metalloporphyrin, 5-{3-methoxyl-4-(4-mercapto butoxy)}phenyl-10,15,20-triphenylporphyrincobalt (MBPPCo), has been synthesized. The electrochemical be...
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