Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes - pp209 - 214

Emma J. Dell, Brian Capozzi, Jianlong Xia, Latha Venkataraman & Luis M. Campos

doi:10.1038/nchem.2160

Understanding the intrinsic electronic properties of building blocks in conjugated materials can provide powerful design guidelines to control charge transport, such as tuning the nature of the charge carriers. Now, single-molecule transport studies of a family of oxidized oligothiophenes have shown that their molecular length determines the dominant carrier type.

Abstract - Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes | Full Text - Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes | PDF (1,823 KB) - Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes | Supplementary information | Chemical compounds

See also: Editorial | Article by Su et al. | Article by Xiang et al.

Stereoelectronic switching in single-molecule junctions - pp215 - 220

Timothy A. Su, Haixing Li, Michael L. Steigerwald, Latha Venkataraman & Colin Nuckolls

doi:10.1038/nchem.2180

Creating molecular components with controllable electronic properties is crucial to the realization of nanoscale devices. Now, a single-molecule conductance switch that operates through a stereoelectronic effect has been developed. The sub-ångström control of a scanning tunnelling microscope is used to switch reversibly between two distinct sets of rotational isomers, which differ greatly in their electronic character.

Abstract - Stereoelectronic switching in single-molecule junctions | Full Text - Stereoelectronic switching in single-molecule junctions | PDF (2,212 KB) - Stereoelectronic switching in single-molecule junctions | Supplementary information | Chemical compounds

See also: Editorial Article by Dell et al. | Article by Xiang et al.

Intermediate tunnelling–hopping regime in DNA charge transport - pp221 - 226

Limin Xiang, Julio L. Palma, Christopher Bruot, Vladimiro Mujica, Mark A. Ratner & Nongjian Tao

doi:10.1038/nchem.2183

Charge transport in molecular systems is typically through coherent tunnelling over a short distance or incoherent hopping over a long distance. An intermediate regime between those two transport mechanisms has now been found for DNA systems with stacked guanine–cytosine sequences.

Abstract - Intermediate tunnelling–hopping regime in DNA charge transport | Full Text - Intermediate tunnelling–hopping regime in DNA charge transport | PDF (2,373 KB) - Intermediate tunnelling–hopping regime in DNA charge transport | Supplementary information

See also: Editorial Article by Dell et al. | Article by Su et al.

Sequence-independent and rapid long-range charge transfer through DNA - pp156 - 159

Kiyohiko Kawai, Haruka Kodera, Yasuko Osakada & Tetsuro Majima

doi:10.1038/nchem.171

The presence of adenine–thymine base pairs in DNA duplexes significantly reduces their electrical conductivity. However, by replacing adenine with a closely related analogue that does not disturb the normal complementary base pairing, it is possible to make duplexes that can transfer charge efficiently without having to use only guanine–cytosine base pairs.

Abstract - | Full Text - Sequence-independent and rapid long-range charge transfer through DNA | PDF (828 KB) - Sequence-independent and rapid long-range charge transfer through DNA | Supplementary information

Subject terms: Physical chemistry | Photochemistry

See also: News and Views by Genereux & Barton

Rectification and stability of a single molecular diode with controlled orientation - pp635 - 641

Ismael Díez-Pérez, Joshua Hihath, Youngu Lee, Luping Yu, Lyudmyla Adamska, Mortko A. Kozhushner, Ivan I. Oleynik & Nongjian Tao

doi:10.1038/nchem.392

The properties of molecular electronic devices can be tuned by tailoring the structures of the molecules from which they are built. Researchers now show that two closely related molecules — each containing a string of four aryl groups — behave very differently when strung between gold electrodes, with the non-symmetrical structure leading to diode-like behaviour.

Abstract - | Full Text - Rectification and stability of a single molecular diode with controlled orientation | PDF (1,374 KB) - Rectification and stability of a single molecular diode with controlled orientation | Supplementary information

Subject terms: Nanotechnology

See also: News and Views by Janes

Exploring local currents in molecular junctions - pp223 - 228

Gemma C. Solomon, Carmen Herrmann, Thorsten Hansen, Vladimiro Mujica & Mark A. Ratner

doi:10.1038/nchem.546

A methodology for describing local electronic transmission through bridging molecules between metallic electrodes is presented. Its application to simple alkane, phenyl and cross-conjugated systems highlights an unexpected number of cases whereby ‘through space’, rather than ‘through bond’ terms dominate and that interference effects coincide with the reversal of ring currents.

Abstract - Exploring local currents in molecular junctions | Full Text - Exploring local currents in molecular junctions | PDF (1,872 KB) - Exploring local currents in molecular junctions | Supplementary information

Subject terms: Theoretical chemistry | Physical chemistry

DNA charge transport over 34 nm - pp228 - 233

Jason D. Slinker, Natalie B. Muren, Sara E. Renfrew & Jacqueline K. Barton

doi:10.1038/nchem.982

The potential for using molecules as wires in nanoscale electronics is somewhat tempered by the challenges in making long and uniform structures. Now, it has been shown that DNA — which is easily synthesized to precise lengths — can conduct charge over 34 nm on multiplexed gold electrodes, a distance that surpasses most reports of molecular wires.

Abstract - DNA charge transport over 34 nm | Full Text - DNA charge transport over 34 nm | PDF (628 KB) - DNA charge transport over 34 nm | Supplementary information

Subject terms: Biochemistry | Electrochemistry | Nanotechnology

The gold–sulfur interface at the nanoscale - pp443 - 455

Hannu Häkkinen

doi:10.1038/nchem.1352

Thiolate-protected gold surfaces and interfaces are archetypal systems in various fields of current research in nanoscience, materials science, inorganic chemistry and surface science. Examples include self-assembled monolayers of organic molecules on gold, passivated gold nanoclusters and molecule–gold junctions. This Review discusses recent experimental and theoretical breakthroughs that highlight common features of gold-sulfur bonding in these systems.

Abstract - The gold-sulfur interface at the nanoscale | Full Text - The gold–sulfur interface at the nanoscale | PDF (3,309 KB) - The gold–sulfur interface at the nanoscale

Subject terms: Nanotechnology | Surface chemistry

Electron transfer through rigid organic molecular wires enhanced by electronic and electron–vibration coupling - pp899 - 905

Junpei Sukegawa, Christina Schubert, Xiaozhang Zhu, Hayato Tsuji, Dirk M. Guldi & Eiichi Nakamura

doi:10.1038/nchem.2026

The relationship between electron-transfer properties and the structure of molecular electronics is still not fully understood. Now, a rigid and flat molecular wire has been shown to significantly enhance the rate of electron transfer compared with conventional flexible molecular wires. This enhancement is attributable to both conjugation-induced electronic coupling and inelastic electron tunnelling-enabled electron–vibration coupling.

Abstract - Electron transfer through rigid organic molecular wires enhanced by electronic and electron–vibration coupling | Full Text - Electron transfer through rigid organic molecular wires enhanced by electronic and electron–vibration coupling | PDF (3,062 KB) - Electron transfer through rigid organic molecular wires enhanced by electronic and electron–vibration coupling | Supplementary information | Chemical compounds

See also: News and Views by Miller