Breakdown of interference rules in azulene, a nonalternant hydrocarbon

TY - JOUR

T1 - Breakdown of interference rules in azulene, a nonalternant hydrocarbon

AU - Xia, Jianlong

AU - Capozzi, Brian

AU - Wei, Sujun

AU - Strange, Mikkel

AU - Batra, Arunabh

AU - Moreno, Jose R.

AU - Amir, Roey J.

AU - Amir, Elizabeth

AU - Solomon, Gemma

AU - Venkataraman, Latha

AU - Campos, Luis M.

PY - 2014/5/14

Y1 - 2014/5/14

N2 - We have designed and synthesized five azulene derivatives containing gold-binding groups at different points of connectivity within the azulene core to probe the effects of quantum interference through single-molecule conductance measurements. We compare conducting paths through the 5-membered ring, 7-membered ring, and across the long axis of azulene. We find that changing the points of connectivity in the azulene impacts the optical properties (as determined from UV-vis absorption spectra) and the conductivity. Importantly, we show here that simple models cannot be used to predict quantum interference characteristics of nonalternant hydrocarbons. As an exemplary case, we show that azulene derivatives that are predicted to exhibit destructive interference based on widely accepted atom-counting models show a significant conductance at low biases. Although simple models to predict the low-bias conductance do not hold with all azulene derivatives, we demonstrate that the measured conductance trend for all molecules studied actually agrees with predictions based on the more complete GW calculations for model systems.

AB - We have designed and synthesized five azulene derivatives containing gold-binding groups at different points of connectivity within the azulene core to probe the effects of quantum interference through single-molecule conductance measurements. We compare conducting paths through the 5-membered ring, 7-membered ring, and across the long axis of azulene. We find that changing the points of connectivity in the azulene impacts the optical properties (as determined from UV-vis absorption spectra) and the conductivity. Importantly, we show here that simple models cannot be used to predict quantum interference characteristics of nonalternant hydrocarbons. As an exemplary case, we show that azulene derivatives that are predicted to exhibit destructive interference based on widely accepted atom-counting models show a significant conductance at low biases. Although simple models to predict the low-bias conductance do not hold with all azulene derivatives, we demonstrate that the measured conductance trend for all molecules studied actually agrees with predictions based on the more complete GW calculations for model systems.

U2 - 10.1021/nl5010702

DO - 10.1021/nl5010702

M3 - Journal article

C2 - 24745894

SN - 1530-6984

VL - 14

SP - 2941

EP - 2945

JO - Nano Letters

JF - Nano Letters

IS - 5

ER -