Interest in molecular scale electronics systems originates from the intention to miniaturise and harness the potential of electron scale electronic transfer phenomena. Current physical investigations have focused on producing and measuring systems with single molecular pathways and/or containing simple redox-active centres. Herein is described the synthesis linear, branched and cyclic {Ru(dppe)2} and {FeCp2} containing systems to enable the study of quantum interference effects and the resulting phenomena from multi-electronic pathways.
In Chapter 3, a new methodology has been developed and utilised to synthesise a range of novel 1’,1’’’-biferrocene containing systems. The versatility of this method has produced an array of linear 1’,1’’’-biferrocene containing molecular wires with varying gold binding groups to allow comparison of charge through different binding groups and orientations. The multi-valency of these systems has been probed by electrochemistry, spectroelectrochemistry and DFT to classify all these systems as on the Class II/III border.
The synthetic and design considerations to organometallic system are discussed, including several different routes to the cyclisation of covalently bonded conjugated systems. These results, highlight the importance of intramolecular cyclisation routes for these and result in four different cyclic products being reported. The linear, branched and cyclic {Ru(dppe)2} containing systems that resulted from these investigations will enable the study of conductance effects resulting from multiple electronic pathways and redox activity and the linear, asymmetric and symmetric cyclic ferrocene systems will complement these studies with increased redox activity and interference effects.
The cyclic, branched and linear systems and have been evaluated and compared for their charge transfer properties through; electrochemistry, IR spectroscopy, spectroelectrochemistry and DFT enabling the classification of the mixed valent species and discussion of through bond and through space communication within the branched and cyclic systems.