Organometallic Single-Molecule Electronics: Tuning Electron Transport through X(diphosphine)2FeC4Fe(diphosphine)2X Building Blocks by Varying the Fe–X–Au Anchoring Scheme from Coordinative to Covalent

2014 ◽  
Vol 136 (41) ◽  
pp. 14560-14569 ◽  
Author(s):  
Franziska Lissel ◽  
Florian Schwarz ◽  
Olivier Blacque ◽  
Heike Riel ◽  
Emanuel Lörtscher ◽  
...  
2015 ◽  
Vol 44 (4) ◽  
pp. 875-888 ◽  
Author(s):  
C. J. Lambert

This tutorial outlines the basic theoretical concepts and tools which underpin the fundamentals of phase-coherent electron transport through single molecules.


2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>


2021 ◽  
Vol 12 (4) ◽  
pp. 1256-1261
Author(s):  
Soran Jahangiri ◽  
Juan Miguel Arrazola ◽  
Alain Delgado

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6953-6958 ◽  
Author(s):  
Y. J. Dappe ◽  
C. González ◽  
J. C. Cuevas

We present anab initiostudy of the use of carbon-based tips as electrodes in single-molecule junctions. We show that carbon tips can be combined with other carbon nanostructures to form all-carbon molecular junctions with molecules like benzene or C60. Results show that the use of carbon tips can lead to conductive molecular junctions and open new perspectives in all-carbon molecular electronics.


2018 ◽  
Vol 4 (4) ◽  
pp. 43 ◽  
Author(s):  
Luca Rigamonti ◽  
Manuela Vaccari ◽  
Fabrizio Roncaglia ◽  
Carlo Baschieri ◽  
Alessandra Forni

In continuation of our work on supramolecular architectures of single-molecule magnets (SMMs) as a promising strategy in developing their magnetic performance, in this paper we report the synthesis and single crystal X-ray structure of the centered triangular tetrairon(III) SMM, [Fe4(PhpPy)2(dpm)6], Fe4 (Hdpm = dipivaloylmethane, H3PhpPy = 2-(hydroxymethyl)-2-(4-(pyridine-4-yl)phenyl)propane-1,3-diol), and its assembly in the coordination polymer {[Fe4(PhpPy)2(dpm)6Ag](ClO4)}n, Fe4Ag, upon reaction with silver(I) perchlorate. Thanks to the presence of the pyridyl rings on the two tripodal ligands, Fe4 behaves as divergent ditopic linker, and due to the Fe4:AgClO4 1:1 ratio, Fe4Ag probably possesses a linear arrangement in which silver(I) ions are linearly coordinated by two nitrogen atoms, forming 1D chains whose positive charge is balanced by the perchlorate anions. The stabilization of such a polymeric structure can be ascribed to the long distance between the two donor nitrogen atoms (23.4 Å) and their donor power. Fe4Ag shows slow relaxation of the magnetization which follows a thermally activated process with Ueff/kB = 11.17(18) K, τ0 = 2.24(17) 10−7 s in zero field, and Ueff/kB = 14.49(5) K, τ0 = 3.88(8) 10−7 s in 1-kOe applied field, in line with what reported for tetrairon(III) SMMs acting as building blocks in polymeric structures.


2017 ◽  
Vol 73 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Danilo Stinghen ◽  
André Luis Rüdiger ◽  
Siddhartha O. K. Giese ◽  
Giovana G. Nunes ◽  
Jaísa F. Soares ◽  
...  

High-spin cobalt(II) complexes are considered useful building blocks for the synthesis of single-molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl2, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single-crystal X-ray diffraction analyses.trans-Tetrakis(acetonitrile-κN)bis(tetrahydrofuran-κO)cobalt(II) bis[(acetonitrile-κN)trichloridocobaltate(II)], [Co(C2H3N)4(C4H8O)2][CoCl3(C2H3N)]2, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymercatena-poly[[tetrakis(propan-2-ol-κO)cobalt(II)]-μ-chlorido-[dichloridocobalt(II)]-μ-chlorido], [Co2Cl4(C3H8O)4], (2′), was prepared by direct reaction between anhydrous CoCl2and propan-2-ol in an attempt to rationalize the formation of the CoCl2–alcohol adduct (2), probably CoCl2(HOiPr)m. The binuclear complex di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-2κ2Cl-tetrakis(tetrahydrofuran-1κO)dicobalt(II), [Co2Cl4(C4H8O)4], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen-bond network that appears to favour atransarrangement of the chloride ligands in the octahedral moiety; this differs from thecisdisposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.


2019 ◽  
Vol 116 (23) ◽  
pp. 11247-11252 ◽  
Author(s):  
Toru Kondo ◽  
Jesse B. Gordon ◽  
Alberta Pinnola ◽  
Luca Dall’Osto ◽  
Roberto Bassi ◽  
...  

Biological systems are subjected to continuous environmental fluctuations, and therefore, flexibility in the structure and function of their protein building blocks is essential for survival. Protein dynamics are often local conformational changes, which allows multiple dynamical processes to occur simultaneously and rapidly in individual proteins. Experiments often average over these dynamics and their multiplicity, preventing identification of the molecular origin and impact on biological function. Green plants survive under high light by quenching excess energy, and Light-Harvesting Complex Stress Related 1 (LHCSR1) is the protein responsible for quenching in moss. Here, we expand an analysis of the correlation function of the fluorescence lifetime by improving the estimation of the lifetime states and by developing a multicomponent model correlation function, and we apply this analysis at the single-molecule level. Through these advances, we resolve previously hidden rapid dynamics, including multiple parallel processes. By applying this technique to LHCSR1, we identify and quantitate parallel dynamics on hundreds of microseconds and tens of milliseconds timescales, likely at two quenching sites within the protein. These sites are individually controlled in response to fluctuations in sunlight, which provides robust regulation of the light-harvesting machinery. Considering our results in combination with previous structural, spectroscopic, and computational data, we propose specific pigments that serve as the quenching sites. These findings, therefore, provide a mechanistic basis for quenching, illustrating the ability of this method to uncover protein function.


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