Smart Home Sleep Respiratory Monitoring System Based on a Breath-Responsive Covalent Organic Framework.

A smart home sleep respiratory monitoring system based on a breath-responsive covalent organic framework (COF) was developed and utilized to monitor the sleep respiratory behavior of real sleep apnea patients in this work. The capacitance of the interdigital electrode chip coated with COFTPDA-TFPy exhibits thousands-level reversible responses to breath humidity gases, with subsecond response time and robustness against environmental humidity. A miniaturized printed circuit board, an open-face-mask-based respiratory sensor, and a smartphone app were constructed for the wearable wireless smart home sleep respiratory monitoring system. Leveraging the sensitive and rapid reversible response of COFs, the COF-based respiratory monitoring system can effectively record normal breath, rapid breath, and breath apnea, enabling over a thousand cycles of hour-level continuous monitoring during daily wear. Next, we took the groundbreaking step of advancing the humidity sensor to the clinical trial stage. In clinical experiments on real sleep apnea patients, the COF-based respiratory monitoring system successfully recorded hour-level sleep respiratory data and differentiated the breathing behavior characteristics and severity of sleep apnea patients and subjects with normal sleep function and primary snoring patients. This work successfully advanced humidity sensors into clinical research for real patients and demonstrated the enormous application potential of COF materials in clinical diagnosis.

A sweat-responsive covalent organic framework film for material-based liveness detection and sweat pore analysis.

Covalent organic frameworks have shown considerable application potential and exceptional properties in the construction of stimulus-responsive materials. Here, we designed a sweat-responsive covalent organic framework film for material-based fingerprint liveness detection. When exposed to human sweat, the COFTPDA-TFPy film can transform from yellow to red. The COFTPDA-TFPy film, when touched by living fingers, can produce the naked-eye-identified fingerprint pattern through the sweat-induced color change, while artificial fake fingerprints cannot. This technique, which we named material-based liveness detection, can thus intuitively discern living fingers from fake fingerprints with a 100% accuracy rate. Additionally, the distribution of sweat pores on human skin can also be collected and analyzed by shortening the contact time. By merely washing them with ethanol, all the samples can be utilized again. This work inventively accomplished material-based liveness detection and naked-eye-identified sweat pore analysis and highlighted their potential for use in clinical research and personal identification.

Multiple heteroatom substitution effect on destructive quantum interference in tripodal single-molecule junctions.

Quantum interference (QI) has been identified as a promising strategy for designing molecular-scale electronic devices. Heteroatom doping can effectively tailor the local structures and electronic states of intrinsic molecules, and endow them with modified electron transport properties. Herein, the impacts of multiple heteroatom substitution on destructive quantum interference (DQI) have been investigated based on tripodal meta-linked phenyl derivatives. Orbital views based on the Hückel method qualitatively predict the meta-anchored molecules with DQI features, while the introduction of nitrogen atoms can alleviate the suppression of DQI at the Fermi level (EF). This is generally consistent with the movement or even removal of the antiresonance dips in transmission spectra. The substituent on position 2 can raise the antiresonance energy, while the substituent on position 4 or 6 can lower the antiresonance energy. When more than one nitrogen atom is incorporated, the impact of the substitution on positions 4 and 6 can be superimposed and the substitution on positions 2 and 4 can be partly cancelled. The experimental single-molecule conductance for tripodal molecules follows the trend of 0N-3SMe < 1N-3SMe < 3N-3SMe < 2N-3SMe, in agreement with the theoretical prediction. Additionally, the regulation is the intrinsic property depending on the position and number of the nitrogen atoms in the backbone and is irrelevant to the number and type of the anchoring groups. Our findings provide qualitative guidance for tuning the electron transport based on DQI in heterocycle molecular devices.

Constructing Stable Chromenoquinoline-Based Covalent Organic Frameworks via Intramolecular Povarov Reaction.

Chemically stable chromenoquinoline (CQ)-based covalent organic frameworks (COFs) were constructed by postsynthetic conversion of imine COFs. The key step of an intramolecular Povarov reaction can transform a preintegrated alkyne group to bridge the benzene rings on both sides of the imine linkage via chemical bonds, affording a ladder-type CQ linkage. This novel approach achieves a high cyclization degree of 80-90%, which endows the CQ-COFs with excellent chemical stability toward strong acid, base, and redox reagents. The synthetic approach can be applied to various monomers with different symmetries and functional core moieties. The absorption and fluorescence intensities of CQ-COFs are sensitive to acid, which allows for dual-mode sensing of strongly acidic environments.

Direct Noncovalent Activation of α,ß-Unsaturated Aldehydes for the Stereodivergent Synthesis of Substituted Cyclohexenes.

HOMO-raising noncovalent activation of α-aryl α,ß-unsaturated aldehydes using a bifunctional Brønsted base catalyst is achieved. The catalytically generated dienolate intermediate undergoes all-carbon [4+2] cyclizations with nitroolefins, leading to chiral cyclohexenes with four contiguous stereocenters in high yields and with excellent enantioseletivity. Furthermore, the diastereodivergent synthesis of the products is realized by introducing a second steric control to the bifunctional catalyst; 4 isomers out of 16 possible stereoisomers of the products were selectively produced by simple use of two catalysts and their (pseudo)enantiomers. The results presented here provide new insights into the remote activation of the carbonyl functionality as well as the stereodivergent synthesis of complex chiral molecules with multiple stereocenters.