Nanoarchitectonics for Regulating Molecular Conductance by Multi-Channel Structure.

Molecular electronics represent the cutting-edge and interdisciplinary effort on the future miniaturization of electronic circuits. Benefiting from synthetic chemistry and theoretical insights, molecular circuit studies have promoted devices with increasingly complicated structures. Especially, the evolution of conductive backbones from simple chain-shape single-channel configurations to complex multi-channel architectures marks a pivotal progression.

Enhancing Effect of Fullerene Guest and Counterion on the Structural Stability and Electrical Conductivity of Octahedral Metallo-Supramolecular Cages.

Metallo-supramolecular cages have garnered tremendous attention for their diverse yet molecular-level precision structures. However, the physical properties of these supramolecular ensembles, which are of potential significance in molecular electronics, remain largely unexplored. We herein constructed a series of octahedral metallo-cages and cage-fullerene complexes with notably enhanced structural stability.

Hydroxyl Group as the 'Bridge' to Enhance the Single-Molecule Conductance by Hyperconjugation.

For designing single-molecule devices that have both conjugation systems and structural flexibility, a hyperconjugated molecule with a σ-π bond interaction is considered an ideal candidate. In the investigation of conductance at the single-molecule level, since few hyperconjugation systems have been involved, the strategy of building hyperconjugation systems and the mechanism of electron transport within this system remain unexplored. Based on the skipped-conjugated structure, we present a rational approach to construct a hyperconjugation molecule using a hydroxyl group, which serves as a bridge to interact with the conjugated fragments.

Effectively Enhancing the Conductance of Asymmetric Molecular Wires by Aligning the Energy Level and Symmetrizing the Coupling.

An asymmetric structure is an important strategy for designing highly conductive molecular wires for a gap-fixed molecular circuit. As the conductance enhancement in the current strategy is still limited to about 2 times, we inserted a methylene group as a spacer in a conjugated structure to modulate the structural symmetry. We found that the conductance drastically enhanced in the asymmetric molecular wire to 1.

Fano Resonance in Single-Molecule Junctions.

The Fano resonance in single-molecule junctions could be created by interaction with discrete and continuous molecular orbitals and enables effective electron transport modulation between constructive and destructive interference within a small energy range. However, direct observation of Fano resonance remains unexplored because of the disappearance of discrete orbitals by molecule-electrode coupling. We demonstrated the room-temperature observation of Fano resonance from electrochemical gated single-molecule conductance and current-voltage measurements of a para-carbazole anion junction.

Transport Modulation Through Electronegativity Gating in Multiple Nitrogenous Circuits.

Investigating the correlations of electron transport between multiple channels shows vital promises for the design of molecule-scale circuits with logic operations. To control the electron transport through multiple channels, the modulation of electronegativity shows an effective frontier orbit control method with high universality to explore the interactions between transport channels. Here, two series of compounds with a single nitrogenous conductive channel (Sg) and dual-channels (Db) are designed to explore the influence of electronegativity on electron tunneling transport.

Capturing the Rotation of One Molecular Crank by Single-Molecule Conductance.

Unveiling the internal dynamics of rotation in molecular machine at single-molecule scale is still a challenge. In this work, three crank-shaped molecules are elaborately designed with the conformational flipping between syn and anti fulfilled by two naphthyl groups rotating freely along 1,3-butadiynyl axis. By investigating the single-molecule conductance using scanning tunnelling microscope break junction (STM-BJ) technique and theoretical simulation, the internal rotation of these crank-shaped molecules is well identified through low and high conductance corresponding to syn- and anti-conformations.

Enhancing Phosphorescence through Rigidifying the Conformation to Achieve High-Efficiency OLEDs by Modified PEDOT.

Bis(diphenylphosphinomethyl)phenylphosphine (dpmp)-supported PtAu heterotrinuclear complexes [PtAu(dpmp)(C≡CPh)](ClO) (), [PtAu(dpmp)(DEBf)(C≡CPh)](ClO) (), and [PtAu(dpmp)(DECz)(C≡CPh)](ClO) () were prepared and used in organic light-emitting diodes (OLEDs) as a new class of light emitters, where DEBf = dibenzofuran-4,6-diacetylide and DECz = 3,6-di--butylcarbazole-1,8-diacetylide. Although the flexible structure of PtAu complex (λ = 503 nm, Φ < 0.1%) results in weak photoluminescence in fluid CHCl, complexes (λ = 585 nm, Φ = 4.

Ligand-Dependent Luminescence Properties of Lanthanide-Titanium Oxo Clusters.

A series of lanthanide-titanium oxo clusters (LnTOCs), LnTi-Ac, LnTi--Toluic, and LnTi-Anthra (Ln = Eu and Tb), were prepared based on acetic acid (HAc), -toluic acid (Hp-Toluic), and anthracene-9-carboxylic acid (HAnthra). Crystal structural analysis showed that these clusters possess the same metal topology framework, in which eight Ti ions form a cube and two Ln ions are located on the opposite faces of the cube. The luminescence investigation discovered that the EuTi-Ac displays the highest quantum yields with 15.

Multiphotochromism in an Asymmetric Ruthenium Complex with Two Different Dithienylethenes.

An asymmetric bis(dithienylethene-acetylide) ruthenium(II) complex trans-Ru(dppe)(L1o)(L2o) (1oo) incorporating two different dithienylethene-acetylides (L1o and L2o) was designed to modulate multistate photochromism in view of the well separated ring-closing absorption bands between L1o and L2o. Upon irradiation with appropriate wavelengths of light, complex 1 undergoes stepwise photocyclization and selective photocycloreversion to afford four states (1oo, 1co, 1oc, and 1cc). As a contrast, symmetric complexes trans-Ru(dppe)(L1o) (2oo) and trans-Ru(dppe)(L2o) (3oo) with two identical dithienylethene-acetylides were synthesized, and the corresponding photochromic behavior was investigated.

Cu(iii)triarylcorroles with asymmetric push-pull meso-substitutions: tunable molecular electrochemically catalyzed hydrogen evolution.

The synthesis of four low symmetry AB type Cu(iii)triarylcorroles with meso-aryl substituents that provide electron donating (push) and withdrawing (pull) properties is reported, along with their structural characterization by NMR spectroscopy and X-ray crystallography. An analysis of the structure-property relationships in the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry, and spectroelectrochemistry to trends predicted in DFT and TD-DFT calculations. The results demonstrate that AB type Cu(iii)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolution reactions (HERs) and that their reactivity can be modulated by changing the nature of the B-position meso-substituent.

Photophysical and Electroluminescent Properties of PtAg Acetylide Complexes Supported with meso- and rac-Tetraphosphine.

1,2-Bis[[(diphenylphosphino)methyl](phenyl)phosphino]ethane (dpmppe) was prepared as a new tetraphosphine, and the corresponding rac and meso stereoisomers were successfully separated in view of their solubility difference in acetone. The substitution of PPh into Pt(PPh)(C≡CR) (R = aryl) with rac- or meso-dpmppe gives Pt(rac-dpmppe)(C≡CR) or Pt(meso-dpmppe)(C≡CR), respectively. Using Pt(rac-dpmppe)(C≡CR) or Pt(meso-dpmppe)(C≡CR) as a precursor, PtAg heterotrinuclear cluster complexes were synthesized and characterized by X-ray crystallography.

Magnetocaloric effect and thermal conductivity of Gd(OH)3 and Gd2O(OH)4(H2O)2.

Magnetocaloric effect (MCE) and thermal conductivity of two gadolinium hydroxides, Gd(OH)3 (1) and Gd2O(OH)4(H2O)2 (2), are investigated. Magnetic studies indicate that both 1 and 2 exhibit antiferromagnetic interaction, and the MCE values for 1 and 2 at 2 K and ΔH = 7 T are 62.00 J kg(-1) K(-1) and 59.

Beauty, symmetry, and magnetocaloric effect—four-shell keplerates with 104 lanthanide atoms.

The hydrolysis of Ln(ClO4)3 in the presence of acetate leads to the assembly of the three largest known lanthanide-exclusive cluster complexes, [Nd104(ClO4)6(CH3COO)60(μ3-OH)168(μ4-O)30(H2O)112]·(ClO4)18·(CH3CH2OH)8·xH2O (1, x ≈ 158) and [Ln104(ClO4)6(CH3COO)56(μ3-OH)168(μ4-O)30(H2O)112]·(ClO4)22·(CH3CH2OH)2·xH2O (2, Ln = Nd; 3, Ln = Gd; x ≈ 140). The structure of the common 104-lanthanide core, abbreviated as Ln8@Ln48@Ln24@Ln24, features a four-shell arrangement of the metal atoms contained in an innermost cube (a Platonic solid) and, moving outward, three Archimedean solids: a truncated cuboctahedron, a truncated octahedron, and a rhombicuboctahedron. The magnetic entropy change of ΔS(m) = 46.

Molybdate templated assembly of Ln12Mo4-type clusters (Ln = Sm, Eu, Gd) containing a truncated tetrahedron core.

Three heterometallic cluster complexes {Ln(12)Mo(4)} featuring an Ln(12) core of a distorted truncated tetrahedron were synthesized with the assistance of four MoO(4)(2-) anions as ancillary ligands. Magnetic studies of the {Gd(12)Mo(4)} cluster revealed a large magnetocaloric effect due to the presence of the large number of weakly coupled Gd(III) ions.

Anisotropy of proton transport in an organic-inorganic compound [(C6H10N2)2(SO4)23H2O]n (C6H10N2 = phenylenediammonium dication).

Proton transport along different axes in an organic-inorganic compound [(C(6)H(10)N(2))(2)(SO(4))(2)·3H(2)O](n) (1) was investigated, revealing that proton transport is not only influenced by the structure of the proton transport pathway, but also by the order-disorder extent of proton carriers.

High-nuclearity 3d-4f clusters as enhanced magnetic coolers and molecular magnets.

Four 52-metal-ion 3d-4f cluster complexes featuring a common core of Ln(42)M(10) (Ln = Gd(3+), Dy(3+); M = Co(2+/3+), Ni(2+)) were obtained through self-assembly of the metal ions templated by mixed anions (ClO(4)(-) and CO(3)(2-)). Magnetic studies revealed that the Gd(42)Co(10) and Gd(42)Ni(10) clusters exhibit the largest magnetocaloric effect (MCE) among any known 3d-4f complexes. Replacement of Gd(3+) ions with anisotropic Dy(3+) ions caused significant changes in the magnetic behavior of the clusters; both Dy(42)Co(10) and Dy(42)Ni(10) displayed slow relaxation of the magnetization.