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Research of thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) materials is attractive owing to their extensive applications in various fields. However, achieving organic TADF and RTP materials, particularly those with stimulus‐responsiveness and tunability, is highly desirable but challenging and rarely reported. Herein, two easily synthesized organic molecules are reported with abnormal stimulus‐responsive switchable TADF and RTP effects, in which phenothiazine (PTZ) and benzo[b]phenothiazine (BPTZ) based donor−acceptor molecules PTZ‐DBQ and BPTZ‐DBQ show mechanical‐induced TADF in crystalline phase and photo‐responsive RTP in doping poly(methyl methacrylate) (PMMA) films. This is the first time tetracyclic BPTZ has been used as a donor in achieving TADF and RTP materials, and it is found that BPTZ‐DBQ exhibits remarkably better photophysical properties than PTZ‐DBQ. Systematic studies of experimental results and theoretical calculations indicate that the conformational heterogeneity plays an essential role in achieving mechanical‐induced TADF with mechanochromic luminescence (MCL) property. Embedding the organic phosphors into rigid polymer matrices effectively suppresses the molecular motion, thus turning on the RTP emission channel. The conversion of 3O2 to 1O2 under UV irradiation is mainly responsible for the photo‐induced process. These multifunctional luminescent materials have great potential applications in chemical sensors, information encryption, and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Poly‐p‐phenyleneterephthalamide (PPTA) is widely used in national defense, military industry, and aerospace. However, with weak compression resistance and twist resistance, development of PPTA is greatly impeded. In this work, a novel rigid rod polymer was synthesized by polycondensation of 2,6‐dihydroxyterephthalic acid with 2,3,5,6‐tetraminopyridine which have a large quantity of hydrogen bonds between these polymer chains which provide excellent thermal properties named poly [N‐(2,5‐diamino‐6‐[imino]‐3‐pyridyl)‐4‐formyl‐2,6‐dihydroxybenzamide] (PPDA). The structure of the polymers was characterized by X‐ray diffraction and Fourier transform infrared spectroscopy. The resulting showed that PPDA has good thermal stability and crystallinity, the maximum thermal decomposition temperature close to 900°C under the nitrogen atmosphere. At the same time, PPDA was insoluble in most organic solvents and exhibited good chemical stability. This indicated a superior performance over that of the poly(2,6‐diimidazo(4,5‐b:4′5′‐e)pyridinylene‐1,4(2,5‐dihydroxy)phenylene). In addition, we can foresee that PPDA will play an important role in prospective surgery and aramid areas. [ABSTRACT FROM AUTHOR]

This article used four types rock powder, including granite, gneiss, basalt and limestone, to replace 20% cement to prepare concrete with a water -to -binder of 0.47 or 0.32, and tested their workability and 3 ~1080 d strength, such as cube compressive strength and splitting tensile strength, when the fly ash concrete was selected as the reference sample. The testing results show that the rock powder will affect the concrete workability in different level, and the development model of concrete strength exhibit two-stage feature which contained the rapid development period at 3~180 d and the slow development period at 180 d to 1080 d. Compound exponential function can be used to accurately predict the strength development model of rock powder concrete. The compressive strength ratio of rock powder concrete and fly ash concrete was 0.7~0.9 while the splitting tensile strength ratio was 0.8~1.0. The relationship of compressive strength and splitting tensile strength of rock powder strength can be described by powder function. The 28~90d strength of rock powder concrete was 0.7~0.9 of long-age (1080 d) strength. [ABSTRACT FROM AUTHOR]

Concise and scalable formal syntheses of (-)-quinocarcinamide and (-)-quinocarcin have been achieved in 9 steps with 9% overall yield from simple commercially available chemicals. The synthetic strategy features an ortho -regioselective Pictet-Spengler cyclization for the construction of the tetrahydroisoquinoline skeleton, a stereoselective formal intramolecular [3 + 2] cross cycloaddition of cyclopropane 1,1-diester with an imine for the construction of the 3,8-diazabicyclo[3.2.1]octane skeleton.

In this paper, a 53 Gbps widely tunable transmitter is experimentally demonstrated for the first time, to our knowledge. An InGaAlAs/InP multiple-quantum-well (MQW) wafer is used with an identical layer structure for both the V-coupled cavity laser (VCL) and the electro-absorption modulator (EAM). The VCL uses a shallow-etched waveguide to reduce loss, while the EAM uses a deep-etched waveguide to increase the 3-dB modulation bandwidth. With the temperature varying from 19.5 to 30°C, the transmitter achieves wavelength tuning of 42 channels with a spacing of 100 GHz, corresponding to a tuning range of 32.6 nm from 1538.94 to 1571.54 nm. The static extinction ratio (ER) for all channels is higher than 14 dB. The measured 3-dB electro-optic (E0) bandwidth of the transmitter is over 40 GHz, which fits well with the calculated 3-dB bandwidth. At a fixed peak-to-peak driving voltage of 2.4 V, all channels exhibit clearly an open eye diagram with a 53 Gbps non-return-to-zero (NRZ) signal, while the dynamic ER is higher than 4.5 dB.

We developed a visible-light-mediated [3 + 2] cycloaddition of arylcyclopropylamine with structurally diverse olefins using QXPT-NPh as a highly efficient organic photoredox catalyst. We first achieved the use of various alkyl-substituted alkenes in intermolecular [3 + 2] cycloadditions with cyclopropylamine. We also developed a general and efficient strategy for the construction of structurally diverse cyclopentane-based spiro[4. n ] skeletons with 1,3-difunctional groups, which broadly exist in natural products and synthetic molecules. Furthermore, we proposed a hydrogen-bond mode between the arylcyclopropylamine and the photocatalyst QXPT-NPh .