Rights statement: This is the peer reviewed version of the following article: W. Jiang, Z. Tan, R. Almughathawi, Q. Wu, Z. Liu, J. Liu, S. Hou, G. Zhang, C. J. Lambert, W. Hong, D. Zhang, ChemPhysChem 2021, 22, 2573 which has been published in final form at https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cphc.202100634 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Single-Molecule Charge Transport Modulation Induced by Steric Effects of Side Alkyl Chains
AU - Jiang, Wenlin
AU - Tan, Zhibing
AU - Almughathawi, Renad
AU - Wu, Qingqing
AU - Liu, Zitong
AU - Liu, Junyang
AU - Hou, Songjun
AU - Zhang, Guanxin
AU - Lambert, Colin
AU - Hong, Wenjing
AU - Zhang, Deqing
N1 - This is the peer reviewed version of the following article: W. Jiang, Z. Tan, R. Almughathawi, Q. Wu, Z. Liu, J. Liu, S. Hou, G. Zhang, C. J. Lambert, W. Hong, D. Zhang, ChemPhysChem 2021, 22, 2573 which has been published in final form at https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cphc.202100634 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
PY - 2021/12/13
Y1 - 2021/12/13
N2 - Experimental investigation of the side chain effects on intramolecular charge transport in π-conjugated molecules is essential, but remains challenging. Herein, the dependence of intra-molecular conductance on the nature of branching alkyl chains is investigated through a combination of the scanning tunneling microscope break junction (STM-BJ) technique and density functional theory. Three thiophene-flanked diketopyrrolopyrrole (DPP) derivatives with different branching alkyl chains (isopentane, 3-methylheptane , and 9-methylnonadecane) are used with phenylthiomethyl groups as the anchoring groups. The results of single-molecule conductance measurements show that as the alkyl chain becomes longer, the torsional angles between the aromatic rings increase due to steric crowding, and therefore, the molecular conductance of DPP decreases due to reduction in conjugation. Both theoretical simulations and 1 H NMR spectra demonstrate that the planarity of the DPPs is directly reduced after introducing longer branching alkyl chains, which leads to the reduced conductance. This work indicates that the effect of insulating side chain on single-molecule conductance cannot be neglected, which should be considered for the design of future organic semiconducting materials.
AB - Experimental investigation of the side chain effects on intramolecular charge transport in π-conjugated molecules is essential, but remains challenging. Herein, the dependence of intra-molecular conductance on the nature of branching alkyl chains is investigated through a combination of the scanning tunneling microscope break junction (STM-BJ) technique and density functional theory. Three thiophene-flanked diketopyrrolopyrrole (DPP) derivatives with different branching alkyl chains (isopentane, 3-methylheptane , and 9-methylnonadecane) are used with phenylthiomethyl groups as the anchoring groups. The results of single-molecule conductance measurements show that as the alkyl chain becomes longer, the torsional angles between the aromatic rings increase due to steric crowding, and therefore, the molecular conductance of DPP decreases due to reduction in conjugation. Both theoretical simulations and 1 H NMR spectra demonstrate that the planarity of the DPPs is directly reduced after introducing longer branching alkyl chains, which leads to the reduced conductance. This work indicates that the effect of insulating side chain on single-molecule conductance cannot be neglected, which should be considered for the design of future organic semiconducting materials.
U2 - 10.1002/cphc.202100634
DO - 10.1002/cphc.202100634
M3 - Journal article
VL - 22
SP - 2573
EP - 2578
JO - ChemPhysChem
JF - ChemPhysChem
SN - 1439-4235
IS - 24
ER -