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Photochromic compounds have attracted much attention for their potential applications in photo-actuators, optoelectronic devices and optical recording techniques. This interest is driven by their key photochemical and photophysical properties, which can be reversibly modulated by light irradiation. Among them, diarylethene compounds have garnered extensive investigation due to their excellent thermal stability of both open- and closed-form isomers, robust fatigue resistance, high photocyclization quantum yield and good photochromic performance in both solution and solid phases. However, a notable limitation in expanding the utility of diarylethene compounds is the necessity for ultraviolet light to induce their photochromism. This requirement poses challenges, as ultraviolet light can be detrimental to biological tissues, and its penetration is often restricted in various media. This review provides an overview of design strategies employed in the development of visible-light-responsive diarylethene compounds. These design strategies serve as a guideline for molecular design, with the potential to significantly broaden the applications of all-visible-light-activated diarylethene compounds in the realms of materials science and biomedical science. [ABSTRACT FROM AUTHOR]

Combined extraction of nickel and cobalt from nickel chloride solution using di (2-ethylhexyl) phosphonic acid(P204) and triisooctylamine(N235) as extractants was studied. The effects of organic phase P204 volume fraction, phase ratio, solution pH, saponification rate, organic phase N235 volume fraction, Cl- mass concentration, and reaction temperature on the purification and impurity removal of nickel chloride solution were investigated. The results show that after removing impurities by P204 extraction, N235 is used to extract cobalt and molybdenum from P204 raffinate, the mass concentrations of Ni2+ is 218.10 g/L, and the mass concentrations of Cu2+, Fe3+, Co2+, and Zn2+ in the residual solution 1.1, 1.2, 1.0 and 0.1 mg/L, respectively, under the conditions of 20% volume fraction of P204 in the organic phase of the P204 extraction and impurity removal process, VO/VA = 1.5/1, raw material solution pH = 3.5, saponification rate of 50%, reaction temperature of 40--50 °C, and N235 volume fraction of 16% in the organic phase of the N235 extraction process, VO/VA=1.2/1, Cl- mass concentration ≥280 g/L, reaction temperature of 40~50 °C, P204 Raffinate pH=3.0, and hydrochloric acid acidification concentration of 3 mol/L, which can meet the requirements of producing high quality electrodeposited nickel cathodes. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe (JSS-1) for endogenous SO2 derivatives was developed by using 1,8-naphthalimide and malononitrile dyes on the basis of FRET and the ICT mechanism. JSS-1 possessed excellent photo-stability, deep-red emission signal, large Stokes shift and broad emission window gap. Additionally, it displayed various superiorities in sensing SO2 derivatives, including low sensing limit, high sensitivity and selectivity. Significantly, JSS-1 was successfully employed to track endogenous SO2 derivatives in the endoplasmic reticulum with a high co-localization coefficient of 0.93, and could even be used for the recognition of liver cancer cells. [ABSTRACT FROM AUTHOR]

Photochromic compounds, whose key molecular properties can be effectively modulated by light irradiation, have attracted significant attention for their potential applications in various research fields. The restriction of photoisomerization coloration induced by ultraviolet light limits their applications in the biomedical field and some other fields. Negative photochromism, wherein a relatively stable colored isomer transforms to a colorless metastable isomer under low–energy light irradiation, offers advantages in applications within materials science and life science. This review provides a summary of negatively photochromic compounds based on different molecular skeletons. Their corresponding design strategies and photochromic properties are presented to provide practical guidelines for future investigations. Negatively photochromic compounds can effectively expand the range of photochromic switches for future applications, offering unique properties such as responsiveness to visible to near–infrared light. [ABSTRACT FROM AUTHOR]

The removal of Fe2 from chlorination system by goethite method with NaClO3 as oxidant was studied. The effects of solution pH, dosage of NaClO3 solution, reaction rime and reaction temperature on removal rate of Fe2 were examined. The results show that under the condemns of adding goeite seed, solution pH = 2.5, dosage of NaClO3 solution of 20 g/L, reaction rime of 4 h and reaction temperature of 85 °C, the removal rate of Fe2 is 99. 96%. The removal effect is good. [ABSTRACT FROM AUTHOR]

To better understand the influence of aerosols on micro-properties of clouds and to facilitate weather modification experiments including the analysis of various materials' seeding effect on clouds and precipitation, Beijing Weather Modification Center has taken a decisive step forward by constructing an advanced facility known as Beijing aerosol and cloud interaction chamber (BACIC) in suburban Pinggu district. Boasting an impressive volume of 70 m3, BACIC is not only the largest of its kind in operation in China, but also a testament to the scale of the country's commitment to this sphere of atmospheric science. The enormity of the chamber's capacity facilitates the performance of a broad spectrum of investigations, thus enhancing the comprehensiveness and reliability of the results obtained.Inside BACIC, advanced instrumentation allows for the meticulous measurement and control of temperature, relative humidity, and background aerosol concentration. During 2019-2021, the chamber's capabilities extend further, as demonstrated by successful tests of its ability to create liquid and mixed-phase clouds. These attributes, combined with its capacity to control the cloud droplet size distribution as proved by comparative experiments involving changes in expansion rate and aerosol number concentration, solidify BACIC's standing as a prime location for warm cloud experimentation. The chamber has also been utilized to investigate effects of anthropogenic pollution over North China Plain (NCP) on cloud microphysics. Using ambient air and manipulating the expansion rate, a significant correlation is discovered between such pollution and the size distribution of cloud droplets. Interestingly, while an increase in aerosol leads to higher number of cloud droplets, it also causes a decrease in droplet size, typically within the range of 5-8 μm. Furthermore, an increase in aerosol number concentration leads to a decrease in the activation rate of aerosols into cloud droplets. This activation rate is around 10% for aerosol concentrations less than 5000 cm-3, and remains stable even when the aerosol concentration increases to 10000 cm-3.BACIC is also proved useful in conducting warm cloud expansion experiments involving different hygroscopic materials. It shows that the distribution of submicron (less than 1 μm) hygroscopic catalysts in a polluted environment leads to narrowing of the cloud droplet spectrum. It suggests that for the purpose of artificially reducing warm clouds or fog, it is recommended to use larger particle sizes. The results obtained from these diverse series of experiments have significantly contributed to theoretical knowledge and provide practical guidance for the ongoing development of artificial weather modification techniques.

As an important gaseous pollutant, SO 2 derivatives generally exist and significantly threaten the environment and organism health. Meanwhile, polarity is a disease-related indicator in the organism's microenvironment, where an unregulated variation may disturb the physiological metabolisms. Hence, a superior FRET-based fluorescent sensor (TLA) is presented to track polarity and sulfur dioxide derivatives by dual emission channel, i.e. an elevated red emission at 633 nm with decreasing polarity as well as a reduced red emission at 633 nm and improved blue emission at 449 nm with increasing concentration of SO 2 derivatives. The probe TLA could sensitively detect SO 2 derivatives with ultra-large Stokes shift (273 nm), excellent stability, high selectivity, and low detection limit. Importantly, TLA can accurately detect sulfur dioxide derivatives in real food as well as water samples. Besides, TLA was also fabricated as testing strips and applied to detect SO 2 derivatives in the solution., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Photoinduced tuning of aromaticity and correlative molecular properties has attracted enormous interest in recent years both for modulating photochromism properties and designing novel photochromic materials. Here, we report the synthesis and photochemical characterization of diaryl[5]helicene-based diarylethene molecular switches. 3,4-Bis(2,4-dimethyl-5-phenylthiophen-3-yl)dibenzo[c,g]phenanthrene derivative 1 a showed no photochromic reaction, whereas 3,4-bis(2-methyl-5-phenylthiophen-3-yl)dibenzo[c,g]phenanthrene derivative 2 a and 3,4-bis(5-methyl-2-phenylthiazol-4-yl)dibenzo[c,g]phenanthrene derivative 3 a exhibited reversible photochromism in different aprotic solvents with specific light irradiation. Meanwhile, the diarylethene compounds 2 a and 3 a underwent turn-off mode fluorescence photoswitching together with photoisomerization upon light irradiation. Remarkably, the photoinduced changes in the aromaticity of [5]helicene as a central ethene bridge along with the relative smaller activation energy and higher frequency factor facilitated the thermal bleaching rates of diarylethene switches 2 and 3 in solution. This research provides new insight for designing aromatic diarylethene photoswitches for reversible fluorescence switching, photoinduced changes in aromaticity and further fast thermal back reactions., (© 2023 Wiley-VCH GmbH.)