Conformations of cyclopentasilane stereoisomers control molecular junction conductance

Haixing Li; Marc Hamilton Garner; Zhichun Shangguan; Qianwen Zheng; Timothy A. Su; Madhav Neupane; Panpan Li; Alexandra Velian; Michael L. Steigerwald; Shengxiong Xiao; Colin Nuckolls; Gemma C. Solomon; Latha Venkataraman

doi:10.1039/c6sc01360k

Conformations of cyclopentasilane stereoisomers control molecular junction conductance

Haixing Li, Marc Hamilton Garner, Zhichun Shangguan, Qianwen Zheng, Timothy A. Su, Madhav Neupane, Panpan Li, Alexandra Velian, Michael L. Steigerwald, Shengxiong Xiao^*, Colin Nuckolls, Gemma C. Solomon, Latha Venkataraman

^*Corresponding author for this work

Department of Chemistry

15 Citations (Scopus)

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Abstract

Here we examine the impact of ring conformation on the charge transport characteristics of cyclic pentasilane structures bound to gold electrodes in single molecule junctions. We investigate the conductance properties of alkylated cyclopentasilane cis and trans stereoisomers substituted in the 1,3-position with methylthiomethyl electrode binding groups using both the scanning tunneling microscope-based break junction technique and density functional theory based ab initio calculations. In contrast with the linear ones, these cyclic silanes yield lower conductance values; calculations reveal that the constrained dihedral geometries occurring within the ring are suboptimal for σ-orbital delocalization, and therefore, conductance. Theoretical calculations reproduce the measured conductance trends for both cis and trans isomers and find several distinct conformations that are likely to form stable molecular junctions at room temperature. Due to the weakened σ-conjugation in the molecule, through-space interactions are found to contribute significantly to the conductance. This manuscript details the vast conformational flexibility in cyclopentasilanes and the tremendous impact it has on controlling conductance.

Original language	English
Journal	Chemical Science
Volume	7
Issue number	9
Pages (from-to)	5657-5662
Number of pages	6
ISSN	2041-6520
DOIs	https://doi.org/10.1039/c6sc01360k
Publication status	Published - 2016

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@article{ba134e059c5446f1af0151051813fd61,

title = "Conformations of cyclopentasilane stereoisomers control molecular junction conductance",

abstract = "Here we examine the impact of ring conformation on the charge transport characteristics of cyclic pentasilane structures bound to gold electrodes in single molecule junctions. We investigate the conductance properties of alkylated cyclopentasilane cis and trans stereoisomers substituted in the 1,3-position with methylthiomethyl electrode binding groups using both the scanning tunneling microscope-based break junction technique and density functional theory based ab initio calculations. In contrast with the linear ones, these cyclic silanes yield lower conductance values; calculations reveal that the constrained dihedral geometries occurring within the ring are suboptimal for σ-orbital delocalization, and therefore, conductance. Theoretical calculations reproduce the measured conductance trends for both cis and trans isomers and find several distinct conformations that are likely to form stable molecular junctions at room temperature. Due to the weakened σ-conjugation in the molecule, through-space interactions are found to contribute significantly to the conductance. This manuscript details the vast conformational flexibility in cyclopentasilanes and the tremendous impact it has on controlling conductance.",

author = "Haixing Li and Garner, {Marc Hamilton} and Zhichun Shangguan and Qianwen Zheng and Su, {Timothy A.} and Madhav Neupane and Panpan Li and Alexandra Velian and Steigerwald, {Michael L.} and Shengxiong Xiao and Colin Nuckolls and Solomon, {Gemma C.} and Latha Venkataraman",

year = "2016",

doi = "10.1039/c6sc01360k",

language = "English",

volume = "7",

pages = "5657--5662",

journal = "Chemical Science",

issn = "2041-6520",

publisher = "Royal Society of Chemistry",

number = "9",

}

TY - JOUR

T1 - Conformations of cyclopentasilane stereoisomers control molecular junction conductance

AU - Li, Haixing

AU - Garner, Marc Hamilton

AU - Shangguan, Zhichun

AU - Zheng, Qianwen

AU - Su, Timothy A.

AU - Neupane, Madhav

AU - Li, Panpan

AU - Velian, Alexandra

AU - Steigerwald, Michael L.

AU - Xiao, Shengxiong

AU - Nuckolls, Colin

AU - Solomon, Gemma C.

AU - Venkataraman, Latha

PY - 2016

Y1 - 2016

N2 - Here we examine the impact of ring conformation on the charge transport characteristics of cyclic pentasilane structures bound to gold electrodes in single molecule junctions. We investigate the conductance properties of alkylated cyclopentasilane cis and trans stereoisomers substituted in the 1,3-position with methylthiomethyl electrode binding groups using both the scanning tunneling microscope-based break junction technique and density functional theory based ab initio calculations. In contrast with the linear ones, these cyclic silanes yield lower conductance values; calculations reveal that the constrained dihedral geometries occurring within the ring are suboptimal for σ-orbital delocalization, and therefore, conductance. Theoretical calculations reproduce the measured conductance trends for both cis and trans isomers and find several distinct conformations that are likely to form stable molecular junctions at room temperature. Due to the weakened σ-conjugation in the molecule, through-space interactions are found to contribute significantly to the conductance. This manuscript details the vast conformational flexibility in cyclopentasilanes and the tremendous impact it has on controlling conductance.

AB - Here we examine the impact of ring conformation on the charge transport characteristics of cyclic pentasilane structures bound to gold electrodes in single molecule junctions. We investigate the conductance properties of alkylated cyclopentasilane cis and trans stereoisomers substituted in the 1,3-position with methylthiomethyl electrode binding groups using both the scanning tunneling microscope-based break junction technique and density functional theory based ab initio calculations. In contrast with the linear ones, these cyclic silanes yield lower conductance values; calculations reveal that the constrained dihedral geometries occurring within the ring are suboptimal for σ-orbital delocalization, and therefore, conductance. Theoretical calculations reproduce the measured conductance trends for both cis and trans isomers and find several distinct conformations that are likely to form stable molecular junctions at room temperature. Due to the weakened σ-conjugation in the molecule, through-space interactions are found to contribute significantly to the conductance. This manuscript details the vast conformational flexibility in cyclopentasilanes and the tremendous impact it has on controlling conductance.

U2 - 10.1039/c6sc01360k

DO - 10.1039/c6sc01360k

M3 - Journal article

AN - SCOPUS:84983591629

SN - 2041-6520

VL - 7

SP - 5657

EP - 5662

JO - Chemical Science

JF - Chemical Science

IS - 9

ER -

Conformations of cyclopentasilane stereoisomers control molecular junction conductance

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