Highly Conductive [3×n] Gold‐Ion Clusters Enclosed within Self‐Assembled Cages

Abstract

There is an increasing interest in the electron conductivity of metal-atom wires at the single-molecule level because of their quantized electric properties applicable to conducting wires in ultra-small devices. [1][2][3] In contrast, the single-molecular conductivity of metal-ion wires has never been studied and whether the metal-ion wires are conductive or insulating has been a matter of debate, [4][5][6] because creating metal-ion arrays with a fixed cross section and length between nanogap electrodes is nontrivial. In recent years, several efficient methods have been developed for preparing multinuclear complexes with ordered metal-ion arrays. Among them, [3 n] gold-ion clusters, enclosed in self-assembled cages 1 (Figure 1), are particularly interesting because the stacking number n is uniquely determined by the length of the pillar ligand (4). In expectation of efficient electron transport through metal-ion arrays, single-molecular electron conductivity through [3 n] stacks of gold-ion clusters (2) n (n = 1, 2, or 3) was measured. The cages, 1, which keep the metal ions highly ordered in a [3 n] manner within the cavity, are excellent frameworks for accommodating p-stacked molecules and evaluating their electron-transport properties. [7, 8] We show that the metal-ion arrays are highly conductive, the electron transport being comparable to that through metalatom wires and the absolute conductance value being much larger than that of metal-linked organic wires.We confirmed by ab initio transport calculations that the [3 n] Au I ion clusters would be suitable for high conductance with a negligibly small decay over longer transport distances. We calculated the conductance of the corresponding model arrays, 3·(2 a) n ·3 (n = 1-4) (See the Supporting Information). Figure 2 shows the calculated conductance values, together Figure 1. [3n] Au I ion clusters (2) n enclosed within coordination cages 1 which self-assemble from triazine panel ligands 3, pillar ligand 4, and [(ethylenediamine)M(ONO 2 ) 2 ] (M= Pd or Pt).Figure 2. Computed conductance of [3 n] Au I ion clusters. In the calculation, the stacked arrays 3·(2 a) n ·3 (n = 1-4) sandwiched between Au electrodes were used as simple models for the [3 n] Au I ion clusters. The transport direction is parallel to the Au[111] direction.

Exponential Attenuation of Through-Bond Transmission in a Polyene: Theory and Potential Realizations

“…Just like eq 3, eq 8 is also empirical and comes from early tunneling calculations. So far, β C values have been determined experimentally and theoretically in many molecules, for example, alkanes, 42,43 π-stacked materials, 44,45 metal-ion clusters, 46 extended metal atom chains, 47 and π-conjugated oligomers including oligoenes, 48,49 oligoynes, 50,51 oligoacenes, 52,53 oligothiophenes, 54 oligoporphyrins, 55 oligophenylenes, 56,57 and graphene nanoribbons, 58 combined with various end groups 51 and electrode materials. 59 Although the reported β C values depend on the experimental and theoretical methodologies to a certain degree, 12 π-conjugated systems generally have smaller β C values (around 0.2À0.6 Å À1 ) than σ systems (around 0.6À1.0 Å À1 ).…”

Single Tripyridyl–Triazine Molecular Junction with Multiple Binding Sites

“…The obtained β value of 1.1 Å −1 is larger than those of the π-conjugated molecule (carotenoid; ∼0.5 Å −1 ) and saturated ones (alkane and peptides; ∼1 Å −1 ). 2,17,18 ■ CONCLUSION We have successfully fabricated the single TPTZ molecular junction with the multiple conductance states using STM-BJ under ambient conditions. We found three preferential single…”

Soft Metal Cations Trigger Sandwich‐Cluster Luminescence of a New Au(I)‐Vinylimidazolate Cyclic Trinuclear Complex

“…For these heterometallic clusters, according to reported crystal structures, the inserted metal cations are intercalated between two planar CTCs by six gold(I) atoms in distorted trigonal prismatic coordination geometries. [6,[28][29][30][31][32] The heterometallic clusters 2 and 3 are sparingly soluble in common organic solvents while 4 is quite soluble in acetone. FT-IR spectra of complexes 2-4 do not show significant differences from the FT-IR spectrum of 1 in the mid-IR range, excluding the peaks at 1050 cm À 1 of BF 4…”

“…[18][19][20][21][22][23][24][25] The clusters herein are formed by sandwiching a foreign closed-shell metal cation between two gold(I) CTC molecules, resulting in an [Au 3 ]…M + …[Au 3 ] chemical formula for the resulting heptanuclear cluster. [6,[26][27][28][29][30][31][32] Since they were discovered in 1998, [28] few reports on structure determinations and luminescence properties only cover the central metal cations of Ag + and Tl + . [6,[26][27][28][29][30][31][32] Herein, we also add Cu + and the three ions are sandwiched in a new gold(I) CTCs, reporting the synthesis, structure, photoluminescence, and theoretical modeling of all four compounds.…”

“…[6,[26][27][28][29][30][31][32] Since they were discovered in 1998, [28] few reports on structure determinations and luminescence properties only cover the central metal cations of Ag + and Tl + . [6,[26][27][28][29][30][31][32] Herein, we also add Cu + and the three ions are sandwiched in a new gold(I) CTCs, reporting the synthesis, structure, photoluminescence, and theoretical modeling of all four compounds. The new CTC that π-complexes to these cations is tris(vinylimidazolatogold(I)), 1.…”