Conductance behavior of tetraphenyl-Aza-Bodipys

Markin, A. and Ismael, A.K. and Davidson, R.J. and Milan, D.C. and Nichols, R.J. and Higgins, S.J. and Lambert, C.J. and Hsu, Y.-T. and Yufit, D.S. and Beeby, A. (2020) Conductance behavior of tetraphenyl-Aza-Bodipys. The Journal of Physical Chemistry C, 124 (12). pp. 6479-6485. ISSN 1932-7447

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Abstract

We studied the electrical conductance of single-molecule junctions formed from molecular wires with four anchor groups. Three tetraphenyl-aza-BODIPYs with four or two thiomethyl anchor groups were synthesized, and their single-molecule conductance was measured using break-junction-STM. Using DFT based calculations these compounds were shown to display a combination of a high and low conductance, depending on the molecule's connectivity in the junction. A scissor correction is employed to obtain the corrected HOMO-LUMO gaps and a tight binding model (TBM) is used to highlight the role of transport through the pi system of the tetraphenyl-aza-BODIPY central unit. The three higher-conductance geometries follow the sequence 3 > 4 > 2, which demonstrates that their conductances are correlated with the number of anchors.