The synthesis of thiols, dithiols, isocyanides, diisocyanides, and isocyanothiols. Their use as molecular wires and interconnects
Abstract
A study investigating the use of thiols, dithiols, isocyanides, diisocyanides, and isocyano thiols. Several of these molecules have been synthesized and characterized by standard methods. They have then been used to form self-assembled monolayers on gold surfaces. These SAMs were characterized by reflectance absorbtion infrared spectroscopy, surface enhanced Raman spectroscopy, advancing water contact angle measurements, and ellipsometery. SAMs in the case of the rigid p-phenyl or phenyl ethynyl type formed SAMs with the long molecular axis perpendicular to the surface. Spectroscopically indistinguishable SAMs of the bifunctional molecules can be formed by direct adsorption or by displacing a pre-existing SAM of octadecanethiol.^ The stand up SAMs have been used, in the case of the difunctional molecules, as chemically sticky surfaces. These surfaces have been used to anchor large crystalline gold clusters and a trinuclear nickel cluster to the gold surface. The gold cluster/SAM/gold nanostructures were analyzed by STM. The STM experiments show a room temperature Coulomb Blockade effect. Furthermore, I(V,z) STM experiments in one case showed the first room temperature Coulomb Staircase in a well defined system. The mono-functional molecules are being studied by STM and results are forth coming.^ The bifunctional molecules have also been used to form 2 and 3-dimensional networks of gold clusters. These networks were analyzed by transmission electron microscopy and UV-vis. The 2-dimensional arrays can be formed between two gold contact pads and the current-voltage characteristics of these arrays measured.^ The resistance of a single molecule has been measured two ways. The experimental measurements agree well with theoretical predictions. This is believed to be the first measurement on a single molecule in a well defined system. ^
Degree
Ph.D.
Advisors
Major Professor: Clifford P. Kubiak, Purdue University.
Subject Area
Chemistry, Organic|Engineering, Chemical|Physics, Condensed Matter
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