Département de chimie moléculaire

Controlling charge flow in single mol. circuits with multiple elec. contacts and conductance pathways is a much sought after goal in mol. electronics. In this joint exptl. and theor. study, we advance the possibility of creating single mol. breadboard circuits through an anal. of the conductance of a bis-terpyridine based mol. (TP1). The TP1 mol. can adopt multiple conformations through relative rotations of 7 arom. rings and can attach to electrodes in 61 possible single and multi-terminal configurations through 6 pyridyl groups. Despite this complexity, we show that it is possible to ext. well defined conductance features for the TP1 breadboard and assign them rigorously to the underlying constituent circuits. Mech. controllable break-junction (MCBJ) expts. on the TP1 mol. breadboard show an unprecedented 4 conductance states spanning a range 10 -2G0 to 10 -7G0. Quant. theor. examn. of the conductance of TP1 reveals that combinations of 5 types of single terminal 2-5 ring subcircuits are accessed as a function of electrode sepn. to produce the distinct conductance steps obsd. in the MCBJ expts. We est. the abs. conductance for each single terminal subcircuit and its percentage contribution to the 4 exptl. obsd. conductance states. We also provide a detailed anal. of the role of quantum interference and thermal fluctuations in modulating conductance within the subcircuits of the TP1 mol. breadboard. Finally, we discuss the possible development of mol. circuit theory and exptl. advances necessary for mapping conductance through complex single mol. breadboard circuits in terms of their constituent subcircuits. [on SciFinder(R)]