Room temperature conductance switching in a molecular iron(<scp>iii</scp>) spin crossover junction

Karuppannan, Senthil Kumar; Martín-Rodríguez, Alejandro; Ruiz, Eliseo; Harding, Phimphaka; Harding, David J.; Yu, Xiaojiang; Tadich, Anton; Cowie, Bruce C. C.; Qi, Dongchen; Nijhuis, Christian A.

doi:10.1039/d0sc04555a

Cited by 39 publications

(49 citation statements)

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“…Compared to organic molecular wires, molecules containing transition metal centers have the potential for enhanced conductance , and increased functionality via redox or magnetic properties which can be leveraged to create components such as molecular switches − and memory storage devices. , Metal-centered electronic states or nuclear spin states of molecules containing one or more transition metals can be synthetically tuned and manipulated in situ − for potential applications in spintronics and quantum information science (QIS). − Synthetic efforts to form molecular metal wires include coordination polymers, extended metal atom chains (EMACs), and infinite one-dimensional (1D) chains. − …”

Section: Introductionmentioning

confidence: 99%

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

et al. 2021

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The achievement of atomic control over the organic–inorganic interface is key to engineering electronic and spintronic properties of molecular devices. We leverage insights from inorganic chemistry to create hard–soft acid–base (HSAB) theory-derived design principles for incorporation of single molecules onto metal electrodes. A single molecule circuit is assembled via a bond between an organic backbone and an under-coordinated metal atom of the electrode surface, typically Au. Here, we study molecular composition factors affecting the junction assembly of coordination complexes containing transition metals atoms on Au electrodes. We employ hetero- and homobimetallic lantern complexes and systematically change the coordination environment to vary the character of the intramolecular bonds relative to the electrode-molecule interaction. We observe that trends in the robustness and chemical selectivity of single molecule junctions formed with a range of linkers correlate with HSAB principles, which have traditionally been used to guide atomic arrangements in the synthesis of coordination complexes. We find that this similarity between the intermolecular electrode-molecule bonding in a molecular circuit and the intramolecular bonds within a coordination complex has implications for the design of metal-containing complexes compatible with electrical measurements on metal electrodes. Our results here show that HSAB principles determine which intramolecular interactions can be compromised by inter molecule-electrode coordination; in particular on Au electrodes, soft–soft metal–ligand bonding is vulnerable to competition from soft–soft Au-linker bonding in the junction. Neutral donor–acceptor intramolecular bonds can be tuned by the Lewis acidity of the transition metal ion, suggesting future synthetic routes toward incorporation of transition metal atoms into molecular junctions for increased functionality of single molecule devices.

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Section: Introductionmentioning

confidence: 99%

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

et al. 2021

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“… 20 A similar strategy has recently led to the production of molecular monolayers prepared by simple immersion of the substrate in highly diluted solutions of mononuclear Fe II SCO complexes on gold substrates and successfully tested as spintronic devices. 26 …”

Section: Introductionmentioning

confidence: 99%

Bistable Hofmann-Type Fe^II Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces

et al. 2021

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Aiming at investigating the suitability of Hofmann-type two-dimensional (2D) coordination polymers {Fe II (L ax ) 2 [M II (CN) 4 ]} to be processed as single monolayers and probed as spin crossover (SCO) junctions in spintronic devices, the synthesis and characterization of the M II derivatives (M II = Pd and Pt) with sulfur-rich axial ligands (L ax = 4-methyl- and 4-ethyl-disulfanylpyridine) have been conducted. The thermal dependence of the magnetic and calorimetric properties confirmed the occurrence of strong cooperative SCO behavior in the temperature interval of 100–225 K, featuring hysteresis loops 44 and 32.5 K/21 K wide for Pt II -methyl and Pt II /Pd II -ethyl derivatives, while the Pd II -methyl derivative undergoes a much less cooperative multistep SCO. Excluding Pt II -methyl, the remaining compounds display light-induced excited spin-state trapping at 10 K with T LIESST temperatures in the range of 50–70 K. Single-crystal studies performed in the temperature interval 100–250 K confirmed the layered structure and the occurrence of complete transformation between the high- and low-spin states of the Fe II center for the four compounds. Strong positional disorder seems to be the source of elastic frustration driving the multistep SCO observed for the Pd II -methyl derivative. It is expected that the peripheral disulfanyl groups will favor anchoring and growing of the monolayer on gold substrates and optimal electron transport in the device.

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“…On the other hand, the C 1s region in Figure d contains an intense peak at ∼284.6 eV accompanied by a weak shoulder at a higher binding energy of 285.6 eV. The main peak at ∼284.6 eV is attributed to C–C in the aromatic backbone. ,,,,− Due to a higher degree of conjugation for the oligoacene backbone, the peak shifts to a lower binding energy. The peak at 285.6 eV is assigned to C–N, − , and/or to a shake-up process in the aromatic matrix. ,,,, The experimental atomic ratios of N/C is 8.3, 11.6, 17.1, 9.8, and 13.5 for Ph-NH 2 , BP-NH 2 , TP-NH 2 , Naph-NH 2 , and Anth-NH 2 SAMs, respectively, which are consistent with the theoretical values, see Table S2.…”

Section: Results and Discussionmentioning

confidence: 97%

Amine-Anchored Aromatic Self-Assembled Monolayer Junction: Structure and Electric Transport Properties

Tian

Martine

et al. 2021

Langmuir

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We studied the structure and transport properties of aromatic amine self-assembled monolayers (NH2-SAMs) on an Au surface. The oligophenylene and oligoacene amines with variable lengths can form a densely packed and uniform monolayer under proper assembly conditions. Molecular junctions incorporating an eutectic Ga–In (EGaIn) top electrode were used to characterize the charge transport properties of the amine monolayer. The current density J of the junction decreases exponentially with the molecular length (d), as J = J 0 exp(−βd), which is a sign of tunneling transport, with indistinguishable values of J 0 and β for NH2-SAMs of oligophenylene and oligoacene, indicating a similar molecule–electrode contact and tunneling barrier for two groups of molecules. Compared with the oligophenylene and oligoacene molecules with thiol (SH) as the anchor group, a similar β value (∼0.35 Å‑1) of the aromatic NH2-SAM suggests a similar tunneling barrier, while a lower (by 2 orders of magnitude) injection current J 0 is attributed to lower electronic coupling Γ of the amine group with the electrode. These observations are further supported by single-level tunneling model fitting. Our study here demonstrates the NH2-SAMs can work as an effective active layer for molecular junctions, and provide key physical parameters for the charge transport, paving the road for their applications in functional devices.

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Room temperature conductance switching in a molecular iron(iii) spin crossover junction

Abstract: Herein, we report the first room temperature switchable Fe(iii) molecular spin crossover (SCO) tunnel junction.

Cited by 39 publications

References 63 publications

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

Bistable Hofmann-Type Fe^II Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces

Amine-Anchored Aromatic Self-Assembled Monolayer Junction: Structure and Electric Transport Properties

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Room temperature conductance switching in a molecular iron(iii) spin crossover junction

Abstract: Herein, we report the first room temperature switchable Fe(iii) molecular spin crossover (SCO) tunnel junction.

Cited by 39 publications

References 63 publications

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

Hard–Soft Chemistry Design Principles for Predictive Assembly of Single Molecule-Metal Junctions

Bistable Hofmann-Type FeII Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces

Amine-Anchored Aromatic Self-Assembled Monolayer Junction: Structure and Electric Transport Properties

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Bistable Hofmann-Type Fe^II Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces