Despite the observation of noncovalent interactions between chalcogen atoms in X-ray crystal structures, catalysis that harnesses the power of such chalcogen−chalcogen bonding interactions to produce advanced molecules remains an unresolved problem. Here, we show that a class of extraordinary chalcogenbonding catalysts enables assembly of discrete small molecules including three β-ketoaldehydes and one indole, leading to the construction of N-heterocycles in a highly efficient manner. The strong activation ability of these rationally designed catalysts provides a general solution to the intrinsic limitations of chalcogen bonding catalysis.

The noncovalent S···O bonding interaction is an evolutionary force that has been smartly exploited by nature to modulate the conformational preferences of proteins. The employment of this type of weak noncovalent force to drive chemical reactions is promising yet remains largely elusive. Herein, we describe a dual chalcogen–chalcogen bonding catalysis strategy that the distinct chalcogen atoms simultaneously interact with two chalcogen-based electron donors to give rise to the catalytic activity, thus facilitating chemical reactions. Conventional approaches to the Rauhut–Currier-type reactions require the use of strongly nucleophilic Lewis bases as essential promoters. The implementation of this dual chalcogen–chalcogen bonding catalysis strategy allows the simultaneous Se···O bonding interaction between chalcogen-bonding donors and an enone and an alcohol, enabling the realization of the Rauhut–Currier-type reactions in a distinct way. The further implementation of a consecutive dual Se···O bonding catalysis approach enables the achievement of an initial Rauhut–Currier-type reaction to give an enone product which further undergoes an alcohol-addition induced cyclization reaction. This work demonstrates that the nearly linear chalcogen-bonding interaction can differentiate similar alkyl groups to give rise to regioselectivity. Moreover, the new strategy shows its advantage as it not only enables less reactive substrates working efficiently but tolerates inaccessible substrates using conventional methods.

Non-dispersive infrared (NDIR) spectroscopy analyzes the concentration of target gases based on their characteristic infrared absorption. In conventional NDIR gas sensors, an infrared detector has to pair with a bandpass filter to select the target gas. However, multiplexed NDIR gas sensing requires multiple pairs of bandpass filters and detectors, which makes the sensor bulky and expensive. Here, we propose a multiplexed NDIR gas sensing platform consisting of a narrowband infrared detector array as read-out. By integrating plasmonic metamaterial absorbers with pyroelectric detectors at the pixel level, the detectors exhibit spectrally tunable and narrowband photoresponses, circumventing the need for separate bandpass filter arrays. We demonstrate the sensing of H2S, CH4, CO2, CO, NO, CH2O, NO2, SO2. The detection limits of common gases such as CH4, CO2, and CO are 63 ppm, 2 ppm, and 11 ppm, respectively. We also demonstrate the deduction of the concentrations of two target gases in a mixture.

The activation of aziridines typically involves the use of strong Lewis acids or transition metals, and methods relying on weak interactions are rare. Herein, we report that cooperative chalcogen bonding interactions in confined sites can activate sulfonyl-protected aziridines. Among the several possible distinct bonding modes, our experiments and computational studies suggest that an activation mode involving the cooperative Se···O and Se···N interactions is in operation. The catalytic reactions between weakly bonded supramolecular species and nonactivated alkenes are considered as unfavorable approaches. However, here we show that the activation of aziridines by cooperative Se···O and Se···N interactions enables the cycloaddition of weakly bonded aziridine-selenide complex with nonactivated alkenes in a catalytic manner. Thus, weak interactions can indeed enable these transformations and are an alternative to methods relying on strong Lewis acids.

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A mathematical model was proposed to calculate the breakdown time based on the theoretical analysis of the discharging mechanism for three-electrode trigatron switch with the trigger electrode located inside the main electrode. The simulation result demonstrates that the breakdown time decreases with operating voltage increasing. The dependence on voltage is weak for the high voltages. A threshold voltage exists and threshold voltage increases with the main gap. If the charging voltage is enough high, the breakdown time is about same for both main gaps. Experimental result agrees with the simulation result very well.

The hybridization of mono-crystalline silicon and lithium niobate thin films (Si-LNOI) can combine the physical properties of Si and the optical properties of LN, and it has emerged as a new material platform for integrated photonics. In this paper, phase modulators in Si-LNOI were demonstrated. First, the phase modulator was designed. According to the simulation, the Si loading strip waveguide had a small mode area due to the large refractive index of Si. This allowed a small electrode gap that resulted in enhancement of the overlap of the optical field and the electrostatic field, and the VπL of the phase modulator could be as small as 3.3 V·cm. Second, phase modulators with a Si loading strip waveguide with a top width of 0.5 μm were fabricated by plasma etching, and the VπL of the phase modulator was measured to be 4.74 V·cm. This study provides useful information for the devices in the Si-LNOI.