Metal‐to‐metal charge transfer (MMCT) describes electron transfer between metal ions, to generate valence isomers with markedly different electronic configurations. In particular, MMCT changes the ...spin states of single‐metal sites and the coupling interactions between them, while also changing the symmetry in charge distribution. The result is a drastic change in both magnetic and electric properties of the affected material. Moreover, MMCT causes significant variation in bond length and absorption spectra, and induces unusual thermal expansion and photochromic behavior. Thus, materials demonstrating MMCT in response to external stimuli are excellent candidates for switchable multifunctional devices with synergistic responses. In this Minireview, recent progress in utilizing MMCT units as actuators to tune magnetic, electric, thermal expansion, and photochromic properties in cyanide‐bridged systems is highlighted, and emphasis is given to the remaining challenges and future perspectives in the field.
Switched on: Metal‐to‐metal charge transfer (MMCT) is widely studied in valence tautomerism compounds and can be used to construct switchable functional materials. Recent progress in the development of MMCT actuators is summarized; including, modulation of molecular nanomagnets, electric and thermal expansion, and photochromic properties.
An artificial while very stable solid electrolyte interphase film is formed on lithium metal using an electrochemical strategy. When this protected Li anode is first used in a Li–O2 battery, the film ...formed on the anode can effectively suppress the parasitic reactions on the Li anode/electrolyte interface and significantly enhance the cycling stability of the Li–O2 battery.
Tumor immune escape is an important part of tumorigenesis and development. Tumor cells can develop a variety of immunosuppressive mechanisms to combat tumor immunity. Exploring tumor cells that ...escape immune surveillance through the molecular mechanism of related immunosuppression in-depth is helpful to develop the treatment strategies of targeted tumor immune escape. The latest studies show that CD24 on the surface of tumor cells interacts with Siglec-10 on the surface of immune cells to promote the immune escape of tumor cells. It is necessary to comment on the molecular mechanism of inhibiting the activation of immune cells through the interaction between CD24 on tumor cells and Siglec-10 on immune cells, and a treatment strategy of tumors through targeting CD24 on the surface of tumor cells or Siglec-10 on immune cells.
It is very challenging to synthesize stable trivalent rare‐earth complexes in which the coordination number is lower than 3 for the high oxidation state, there is a large ion radius and nearly ...non‐bonding character of trivalent lanthanide ions. The bulky phenol ligand ArOH (Ar=2,6‐Dipp2C6H3, Dipp=2,6‐diisopropylphenyl) was utilized to construct low‐coordinate lanthanide compound (ArO)Ln(OAr′) (Ar′=6‐Dipp‐2‐(2′‐iPr‐6′‐CHMe(CH2−)C6H3)C6H3O−; Ln=Tb, Dy, Ho, Er, Tm). These complexes and the free ligand ArOH were isostructural. Magnetic measurements and theoretical studies demonstrated that both the oblate‐type dysprosium and prolate‐type erbium analogues exhibited single‐ion magnet (SIM) behavior. The bulky phenol ligands provided strong uniaxial ligand field, making the dysprosium SIM possessing blocking barrier up to 961 K.
SIM city: Low‐coordinate single‐ion magnets were achieved by intercalation of dysprosium and erbium into a bulky phenol matrix. Both the oblate‐type dysprosium and prolate‐type erbium analogues exhibited single‐ion magnet (SIM) behavior. Furthermore, the dysprosium SIM exhibited blocking barrier up to 961 K.
To recycle rusty stainless‐steel meshes (RSSM) and meet the urgent requirement of developing high‐performance cathodes for potassium‐ion batteries (KIB), we demonstrate a new strategy to fabricate ...flexible binder‐free KIB electrodes via transformation of the corrosion layer of RSSM into compact stack‐layers of Prussian blue (PB) nanocubes (PB@SSM). When further coated with reduced graphite oxide (RGO) to enhance electric conductivity and structural stability, the low‐cost, stable, and binder‐free RGO@PB@SSM cathode exhibits excellent electrochemical performances for KIB, including high capacity (96.8 mAh g−1), high discharge voltage (3.3 V), high rate capability (1000 mA g−1; 42 % capacity retention), and outstanding cycle stability (305 cycles; 75.1 % capacity retention).
Turning waste into treasure: Rusty stainless steel meshes were utilized as solid‐state iron sources with excellent conductivity properties in order to fabricate stable, low‐cost, and flexible binder‐free potassium‐ion battery electrodes. When combined with unique structural design, the reduced graphite oxide‐coated electrodes exhibited high capacities, superior rate capabilities, and excellent cycle performance.
Magnetic and dielectric properties have been tuned simultaneously by external stimuli with rapid and sensitive response, which is crucial to monitor the magnetic state via capacitive measurement. ...Herein, positive charged FeII ions were linked via negative charged (Tp)FeIII(CN)3− (Tp=hydrotris(pyrazolyl)borate) units to form a neutral chain. The spin‐crossover (SCO) on FeII sites could be sensitively triggered via thermal treatment, light irradiation, and pressure. SCO switched the spin state of the FeII ions and antiferromagnetic interactions between FeIII and FeII ions, resulting in significant change in magnetization. Moreover, SCO induced rotation of negative charged (Tp)FeIII(CN)3− units, generating dielectric anomaly due to geometric change of charges distribution. This work provides a rational way to manipulate simultaneous variations in magnetic and dielectric properties utilizing SCO as an actuator to tune spin arrangement, magnetic coupling, and charge distribution.
Magnetic interactions: A spin‐crossover‐actuated magnetic and dielectric transition has been observed. The sensitive response to hydrostatic pressure and large dielectric anomaly could be attributed to a cooperative effect and rotation of the negative charged building block.
Malaria importation can be caused by cross-border movement either of both people and anopheline mosquitoes. However, there still lacks robust evidence of imported malaria caused by Plasmodium spp. ...infected anopheles along international border areas (border-spill malaria). The objectives of this study were to confirm whether an outbreak of Plasmodium vivax malaria is border-spill malaria and assess the effects of China's public health response along China-Myanmar border.
Epidemiological, parasitological and entomological investigations were conducted to investigate the outbreak of border-spill malaria. Meanwhile, comprehensive interventions were carried out to prevent further transmission and reintroduction of malaria.
Rapid diagnostic testing, microscopy and polymerase chain reaction were performed and the infections were confirmed as P. vivax. A total of 22 (9.21%) of 239 workers contracted P. vivax during the outbreak. Multivariate logistic regression analysis identified that the distance of worker shelters in China within 300 meters to the internally displaced person (IDP) camps in Myanmar was a risk factors associated with malaria infection (adjusted odds ratio 7.5920; 95% confidence interval, 2.6079-22.1013; P = 0.0002). After comprehensive interventions, malaria transmission was successfully interpreted and prevented at the project site till the completion of project on 14 January 2020, and recurrence of P. vivax malaria was not detected by the end of 2020.
This study provided robust evidence of border-spill malaria along China-Myanmar border. Malaria parasite reservoir and distance travelled by female anopheline mosquitoes are two determinants for border-spill malaria. The public health response to the outbreak indicates that the malaria surveillance and response system works well in preventing reintroduction of malaria. However, prevention of border-spill malaria is still a major challenge in the Yunnan border area, China.
In the present study, an analytical method has been developed and validated for the simultaneous detection and quantification of 19 PFRs (14 legacy organophosphorus flame retardants (PFRs) and 5 ...emerging PFRs (ePFRs)) and 20 plasticizers (7 legacy plasticizers (LPs) and 13 alternative plasticizers (APs)). Sample preparation was based on the combination of previously validated analytical protocols including ultrasonic extraction and Florisil fractionation/cleanup. The analysis was performed by using liquid chromatography–tandem mass spectrometry (LC-MS/MS) for all targeted compounds, except for bis (2-ethylhexyl) phthalate (DEHP) and bis (2-ethylhexyl) terephthalate (DEHT), for which the separation of the isomers resulted in more favorable gas chromatography–electron ionization–mass spectrometry (GC-EI-MS). The new method was in-house validated by applying two levels of fortification in dust. The achieved linearity (
R
2
) ranged between 0.993 and 0.999. Limits of detection and quantification (LODs and LOQs) ranged between 1 and 265 ng/g and between 1 and 870 ng/g for all analytes, respectively, except for DEHP and DEHT, for which relatively higher LODs (665 and 1100 ng/g, respectively) and LOQs (2100 and 3500 ng/g, respectively) were observed. Accuracy ranged between 75 and 125% for most of the targeted analytes, and repeatability was good with relative standard deviation (RSD) < 15% for most compounds. Finally, the method was applied for the determination and quantification of the targeted chemicals in house dust samples (
n
= 10) from the megacity of Guangzhou (China). Median values ranged from 3 to 210 ng/g for PFRs, from 4 to 165 ng/g for ePFRs, from 30 to 100,000 ng/g for LPs, and from 6 to 34,000 ng/g for APs. Main contributors to the total contamination were LPs 63% and APs 37% in total plasticizers, whereas PFRs and ePFRs contributed 90% and 10% in total flame retardants.
Graphical abstract
High power density is required for power converter in more electric aircraft due to the strict demands of volume and weight, which makes silicon carbide (SiC) extremely attractive for this ...application. In this paper, a prototype of 50-kW SiC two-level three-phase voltage source inverter is demonstrated with a gravimetric power density of 26 kW/kg (without inclusion of filter). A gate assisted circuit is introduced to reduce the switching loss. In addition, the ringings of voltage and current due to parasitic parameters during the switching transition can also be mitigated. A mathematical model with consideration of various parasitic parameters is developed, which illustrates the parasitic effects in high-speed switching SiC power module. The converter is operated at a switching frequency up to 100 kHz and a narrow dead band of 250 ns. The measured efficiency is 97.91%.
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence ...and spin states of metal ions. Herein, a metallocyanate building block is used to link with a FeII‐triazole moiety and generates a mixed‐valence complex {(Tp4‐Me)FeIII(CN)39FeII4(trz‐ph)6}⋅Ph3PMe2⋅(Tp4‐Me)FeIII(CN)3 (1; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between FeIII and one of the FeII sites after heat treatment, resulting in the generation of a new phase, {(Tp4‐Me)FeII(CN)3(Tp4‐Me)FeIII(CN)38 FeIIIFeII3(trz‐ph)6}⋅ Ph3PMe2⋅(Tp4‐Me)FeIII(CN)3 (1 a). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a. Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states.
Two step, one step: A mixed‐valence FeIII/FeII complex 1 was synthesized using (Tp4‐Me)FeIII(CN)3− to link with a FeII‐triazole moiety. Complex 1 underwent a metal‐to‐metal charge transfer (MMCT) between FeIII and one of the FeII sites after heat treatment, resulting in a new isostructural phase of 1 a. The MMCT can turn the two‐step spin crossover (SCO) behavior of 1 into one‐step SCO behavior of 1 a.
PDF
