3.5 Conclusions

Pyridine and quinuclidine ligands functionalized with alkyl disulfide and thiols were prepared in a pure form for preparation of self assembled monolayers on gold. The crystal structure of one of these derivatives revealed close packing of the alkyl groups in an all trans conformation. A bipyridine functionalized with an alkyl disulfide was synthesized.

Syntheses of thiol substituted porphyrins were developed. The porphyrins were prepared with an air stable thioacetate protecting group, which could subsequently be cleaved, although products were found to be air sensitive especially when exposed to light.

To avoid the problem of oxidative polymerization of dithiol porphyrins, and the possibility of incomplete binding of sulfur to a gold surface, porphyrins with a macrocyclic disulfide strap were synthesized. If the strap linked the ortho positions of the porphyrin aryl groups then a pair of atropisomers resulted. The trans atropisomer converted to exclusively the cis isomer on heating. The rate of atropisomerization of free-base porphyrin was greater than that of zinc porphyrin.

A Zn porphyrin dimer with a protected thiol was prepared using Pd coupling chemistry and shown to bind 4,4'-bipyridine in solution. A mixed metal dimer, with protected thiol and carboxylic acid groups, was prepared using similar methodology with the intention of studying binding to gold and indium tin oxide using angular resolved XPS.

Preliminary synthetic experiments on the use of Os3 clusters as infrared reporter groups for monolayers were carried out.


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