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The quest for the single-molecular magnets (SMMs) based on mononuclear transition-metal complexes is focused on the low-coordinate species. No transition-metal complex with a coordination number of eight has been shown to exhibit SMM properties. Here the magnetic studies have been carried out for a mononuclear, eight-coordinate cobalt(II)-12-crown-4 (12C4) complex [Co(II)(12C4)2](I3)2(12C4) (1) with a large axial zero-field splitting. Magnetic measurements show field-induced, slow magnetic relaxation under an applied field of 500 Oe at low temperature. The magnetic relaxation time τ was fitted by the Arrhenius model to afford an energy barrier of Ueff = 17.0 cm(-1) and a preexponential factor of τ0 = 1.5 × 10(-6) s. The work here presents the first example of the eight-coordinate, mononuclear, 3d metal complex exhibiting the slow magnetic relaxation.

Herein, we developed a photolabile spherical nucleic acid (PSNA) for carrier-free and near-infrared (NIR) photocontrolled self-delivery of small-interfering RNA (siRNA) and antisense oligonucleotide (ASO). PSNA comprised a hydrophilic siRNA shell with a hydrophobic core containing a peptide nucleic acid-based ASO (pASO) and NIR photosensitizer (PS). The incorporation of a singlet oxygen (1O2)-cleavable linker between the siRNA and pASO allowed on-demand disassembly of PSNA in tumor cells once 1O2 was produced by the inner PS upon NIR light irradiation. The generated 1O2 could also concurrently promote lysosomal escape of the released siRNA and pASO to reach cytosolic targets. Both in vitro and in vivo results demonstrated that, under NIR light irradiation, PSNA could suppress hypoxia inducible factor-1α (HIF-1α) and B-cell lymphoma 2 (Bcl-2) for gene therapy (GT), which further combined photodynamic therapy (PDT) favored by the released PS to inhibit tumor cell growth. Given its carrier-free, NIR-sensitive, designable, and biocompatible merits, PSNA represents a promising self-delivery nanoplatform for cancer therapy.

Two mononuclear seven-coordinate cobalt(II) complexes [Co(L)3(NO3)2] (L = 4-tert-butylpyridine, 1; L = isoquinoline, 2) were prepared and structurally analyzed by single-crystal X-ray crystallography. The coordination spheres of 1 and 2 exhibit distorted pentagonal bipyramid geometry. Analysis of their direct-current magnetic data reveals the existence of easy plane anisotropy (D > 0) with a small transverse anisotropy (E), which was further confirmed by high-field electron paramagnetic resonance (HFEPR) spectroscopy. Field-induced slow magnetic relaxations were observed under the applied dc field in complexes 1 and 2 by alternating-current magnetic susceptibility measurements. Importantly, these complexes are new instances of mononuclear high-coordinate cobalt(II)-based single-molecule magnets.

Mandarin speakers, like most other language speakers around the world, use spatial terms to talk about time. However, the direction of their mental temporal representation along the front-back axis remains controversial because they use the spatial term "front" to refer to both earlier times (e.g., front-year means "the year before last") and the future (e.g., front-road means "prospect"). Although the linguistic distinction between time- and ego-reference-point spatiotemporal metaphors in Mandarin suggests a promising clarification of the above controversy, there is little empirical evidence verifying this distinction. In this study, Mandarin speakers' time- and ego-reference-point temporal representations on three axes (i.e., sagittal, lateral, and vertical) were separately examined through two tasks. In a time-reference-point task, Mandarin speakers judged whether the time point of the second picture was earlier or later than the time point of the first picture, while in an ego-reference-point task, they judged whether an event or phase had happened in the past or would happen in the future. The results indicate that Mandarin speakers construe an earlier-times-in-front-of-later-times temporal sequence and adopt the front-to-the-future orientation.

To boost intrinsic circularly polarized luminescence (CPL) properties of chiral emitters, an axially chiral biphenyl unit is inlaid in thermally activated delayed fluorescent (TADF) skeleton, urging the participation of chiral source in frontier molecular orbital distributions. A pair of enantiomers, ( R )‐BPPOACZ and ( S )‐BPPOACZ, containing the cyano as electron‐withdrawing moieties and carbazole and phenoxazine as electron‐donating units are synthesized and separated. The circularly polarized TADF enantiomers exhibit both high photoluminescence quantum yield of 86.10% and excellent CPL activities with maximum dissymmetry factor | g PL | values of almost 10 −2 in solution and 1.8 × 10 −2 in doped film, which are among the best values of previously reported small chiral organic materials. Moreover, the circularly polarized organic light‐emitting diodes based on the TADF enantiomers achieve the maximum external quantum efficiency of 16.6% with extremely low efficiency roll‐off. Obvious circularly polarized electroluminescence signals with | g EL | values of 4 × 10 −3 are also recorded.

Organophosphate esters (OPEs) discharged from wastewater treatment plants (WWTPs) have attracted increasing concerns because of their potential risks to aquatic ecosystems. The identification of the structures of OPEs is a prerequisite for subsequent assessment of their environmental impacts, which could hardly be accomplished using traditional target analytical methods. In this study, we describe the use of suspect and nontarget screening techniques for identification of organophosphate triesters and diesters (tri-OPEs and di-OPEs) in the influent and effluent samples acquired from 25 municipal WWTPs across China. There are totally 33 different OPE molecules identified, 11 of which are detected in wastewater for the first time and 4 are new to the public. In all tested samples, di-OPEs account for a significant portion (53% on average) of the total OPEs (ng/L−μg/L). More importantly, most of the OPEs could not be eliminated after treatment in these WWTPs, while some of the di-OPEs even accumulate. The research priority of OPEs in the effluent based on ecological risk was also analyzed, and the results reflected a previously unrecognized exposure risk of emerging OPEs for aquatic living organisms. These findings present a holistic understanding of the environmental relevance of OPEs in WWTPs on a country scale, which will hopefully provide guidance for the upgrade of treatment protocols in WWTPs and even for the modification of governmental regulations in the future.

Three mononuclear cobalt(II) tetranitrate complexes (A)[Co(NO)] with different countercations, PhP (1), MePhP (2), and PhAs (3), have been synthesized and studied by X-ray single-crystal diffraction, magnetic measurements, inelastic neutron scattering (INS), high-frequency and high-field EPR (HF-EPR) spectroscopy, and theoretical calculations. The X-ray diffraction studies reveal that the structure of the tetranitrate cobalt anion varies with the countercation. 1 and 2 exhibit highly irregular seven-coordinate geometries, while the central Co(II) ion of 3 is in a distorted-dodecahedral configuration. The sole magnetic transition observed in the INS spectroscopy of 1-3 corresponds to the zero-field splitting (2(D + 3E)) from 22.5(2) cm in 1 to 26.6(3) cm in 2 and 11.1(5) cm in 3. The positive sign of the D value, and hence the easy-plane magnetic anisotropy, was demonstrated for 1 by INS studies under magnetic fields and HF-EPR spectroscopy. The combined analyses of INS and HF-EPR data yield the D values as +10.90(3), +12.74(3), and +4.50(3) cm for 1-3, respectively. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements reveal the slow magnetization relaxation in 1 and 2 at an applied dc field of 600 Oe, which is a characteristic of field-induced single-molecule magnets (SMMs). The electronic structures and the origin of magnetic anisotropy of 1-3 were revealed by calculations at the CASPT2/NEVPT2 level.