Metal bis(acetylide) complex molecular wires: concepts and design strategies

Abstract

The past decade has seen a remarkable surge in studies of thin-film and single-molecule electronics, due in no small part to the development and advancement of experimental methods for the construction and measurement of metal|molecule|metal junctions. Within the plethora of molecular structures that have been investigated, metal complexes of general form trans-M(C[triple bond, length as m-dash]CR)2(Ln) have attracted attention from the inorganic and organometallic chemistry community in the search for efficient molecular wires due to the potential π-d-π orbital mixing along the molecular backbone. In this article progress towards this goal will be summarised, and design strategies for future molecular components discussed.

Single-molecule junctions of multinuclear organometallic wires: long-range carrier transport brought about by metal–metal interaction

“…Insertion of metal fragments into organic molecular wires is an effective way to make the b factor smaller while increasing the molecular dimensions. 18,19 Single-molecule conductance studies of multimetallic complexes containing metal fragments as repeating units are scarce 20 in contrast to those of selfassembled monolayer systems. [21][22][23][24][25][26] Berke, Stadler, Lörtscher et al reported the single-molecule conductance of multinuclear molecular wires of a diiron complex (Fe2), which dimerized to form a tetrairon complex (Fe4) during break-junction (BJ) measurements using a scanning tunneling microscope (STM) (Fig.…”

Electronic Properties of Poly‐Yne Carbon Chains and Derivatives with Transition Metal End‐Groups

“…in a variety of applications in molecular electronics for instance. [81][82][83][84] Combined with experimental studies, quantum-chemical calculations can aid to unravel the nature of the electronic and physical properties of these systems. [85][86][87][88][89][90] Over the years, with the help of Kohn-Sham density functional theory (DFT) computations, we have ourselves analyzed and compared the electronic and geometrical structures of a large number of such molecular systems containing different carbon bridges and transition metal groups.…”

“…Additionally, the efficiency of diverse linkers allows to convey electronic and magnetic communication between the termini. These compounds have received considerable attention due to the speculation that such assemblies would be well suited for use in a variety of applications in molecular electronics for instance …”

New routes to organometallic molecular junctionsviaa simple thermal processing protocol

“…10 Multiple-molecule junctions are typically constructed via the introduction of a 'top contact' electrode onto a molecular monolayer. Examples include cross-bar junctions, nanoparticle-capped nanopores, the use of liquid metal 17,18,[30][31][32][33] and eutectic metal alloy top electrodes, 19,34 and deposition of pre-formed metal nanoparticles onto a monolayer bearing a suitable ligating functional group on the exposed top surface. 20,21 However, the cross-bar junctions are experimentally demanding, and liquid metal or eutectic electrodes are not likely to translate to device structures.…”

“…28 Although the field of molecular electronics has been advanced through the construction and study of molecular junctions featuring organic compounds, the electrical characteristics of single-molecule junctions formed from inorganic complexes and organometallic molecules have begun to attract increasing attention. [31][32][33][34][35] The growing interest in metal-complex based molecular electronics has also prompted studies of metal complexes within, for example, 'large area' c-AFM, 36 cross-bar 37 and eGaIn junctions, [38][39][40] as well as nanofabricated device platforms. [41][42][43][44][45] This increasing activity is due to the potential that metal complexes offer for not only improving the alignment of critical frontier molecular orbitals with the electrode Fermi levels to increase molecular conductance, 46 but also the potential to exploit the unique redox, magnetic and photochemical properties of metal complexes to engineer electrical characteristics within the junction that cannot be achieved with purely organic compounds.…”