Scaling of quantum interference from single molecules to molecular cages and their monolayers.

The discovery of quantum interference (QI) is widely considered as an important advance in molecular electronics since it provides unique opportunities for achieving single-molecule devices with unprecedented performance. Although some pioneering studies suggested the presence of spin qubit coherence and QI in collective systems such as thin films, it remains unclear whether the QI can be transferred step-by-step from single molecules to different length scales, which hinders the application of QI in fabricating active molecular devices. Here, we found that QI can be transferred from a single molecule to their assemblies. We synthesized and investigated the charge transport through the molecular cages using 1,3-dipyridylbenzene (DPB) as a ligand block with a destructive quantum interference (DQI) effect and 2,5-dipyridylfuran (DPF) as a control building block with a constructive quantum interference (CQI) effect using both single-molecule break junction and large area junction techniques. Combined experiments and calculations revealed that both DQI and CQI had been transferred from the ligand blocks to the molecular cages and the monolayer thin film of the cages. Our work introduced QI effects from a ligand to the molecular cage comprising 732 atoms and even their monolayers, suggesting that the quantum interference could be scaled up within the phase-coherent distance.

NIR-II Photoacoustic Reporter for Biopsy-Free and Real-Time Assessment of Wilson's Disease.

Wilson's disease (WD) is a rare inherited disorder of copper metabolism with pathological copper hyperaccumulation in some vital organs. However, the clinical diagnosis technique of WD is complicated, aggressive, and time-consuming. In this work, a novel ratiometric photoacoustic (PA) imaging nanoprobe in the NIR-II window is developed to achieve noninvasive, rapid, and accurate Cu2+ quantitative detection in vitro and in vivo. The nanoprobe consists of Cu2+ -responsive IR970 dye and a nonresponsive palladium-coated gold nanorod (AuNR-Pd), achieving a concentration-dependent ratiometric PA970 /PA1260 signal change. The urinary Cu2+ content is detectable within minutes down to a detection limit of 76 × 10-9 m. This report acquisition time is several orders of magnitude shorter than those of existing detection approaches requiring complex procedure. Moreover, utilizing the ratiometric PA nanoprobe, PA imaging enables biopsy-free measurement of the liver Cu2+ content and visualization of the liver Cu2+ biodistribution of WD patient, which avoid the body injury during the clinical Cu2+ test using liver biopsy method. The NIR-II ratiometric PA detection method is simple and noninvasive with super precision, celerity, and simplification, which holds great promise as an alternative to liver biopsy for clinical diagnosis of WD.

Massive acceleration of SN2 reaction using the oriented external electric field.

Nucleophilic substitution is one of the most fundamental chemical reactions, and the pursuit of high reaction rates of the reaction is one of the ultimate goals in catalytic and organic chemistry. The reaction barrier of the nucleophilic substitution originates from the highly polar nature of the transition state that can be stabilized under the electric field created by the solvent environment. However, the intensity of the induced solvent-electric field is relatively small due to the random orientation of solvent molecules, which hinders the catalytic effects and restricts the reaction rates. This work shows that oriented external electric fields applied within a confined nanogap between two nanoscopic tips could accelerate the Menshutkin reaction by more than four orders of magnitude (over 39 000 times). The theoretical calculations reveal that the electric field inside the nanogap reduces the energy barrier to increase the reaction rate. Our work suggests the great potential of electrostatic catalysis for green synthesis in the future.