Single‐ion magnets (SIMs), exhibiting slow magnetization relaxation in the absence of the magnetic field, originate from their single spin‐carrier centre. In pursuit of high‐performance magnetic ...properties, such as high spin‐reversal barrier and high blocking temperature, various metal centres were investigated to establish SIMs, including 3d and 5d transition metal ions, 4f lanthanide ions, and 5f actinide ions, which possess unique zero‐field splitting and magnetic properties. Therefore, proper ligand field is of great importance to different types of metals. In the given great breakthroughs since the first SIM, Pc2Tb− (Pc=dianion of phthalocyanine), was reported, strategies of ligand field design have emerged. In this review, the developments of SIMs with different metal centres are summarized, as well as the possible strategies.
How molecular magnetism works: A summary of single‐ion magnets (SIMs) including the development of 3d, 5d, 4f, and 5f metal‐based SIMs and the possible ligand field strategies for high‐performance SIMs constructions.
ion of a chloride ligand from the dysprosium metallocene (Cpttt)2DyCl (1Dy Cpttt=1,2,4‐tri(tert‐butyl)cyclopentadienide) by the triethylsilylium cation produces the first base‐free rare‐earth ...metallocenium cation (Cpttt)2Dy+ (2Dy) as a salt of the non‐coordinating B(C6F5)4− anion. Magnetic measurements reveal that 2DyB(C6F5)4 is an SMM with a record anisotropy barrier up to 1277 cm−1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low‐lying Kramers doublets correspond to a well‐defined MJ value, with no significant mixing even in the higher doublets.
SMMashing: A dysprosium(III) metallocenium cation is a single‐molecule magnet (SMM) with a record anisotropy barrier of 1277 cm−1 and record magnetic blocking up to 60 K, including hysteresis with coercivity.
An extremely rare non‐Kramers holmium(III) single‐ion magnet (SIM) is reported to be stabilized in the pentagonal‐bipyramidal geometry by a phosphine oxide with a high energy barrier of 237(4) cm−1. ...The suppression of the quantum tunneling of magnetization (QTM) at zero field and the hyperfine structures originating from field‐induced QTMs can be observed even from the field‐dependent alternating‐current magnetic susceptibility in addition to single‐crystal hysteresis loops. These dramatic dynamics were attributed to the combination of the favorable crystal‐field environment and the hyperfine interactions arising from 165Ho (I=7/2) with a natural abundance of 100 %.
An extremely rare non‐Kramers holmium(III) single‐ion magnet is reported. The suppression of the quantum tunneling of magnetization at zero field and the hyperfine structures were observed in AC magnetic susceptibility measurements, and were attributed to the combination of a favorable crystal‐field environment and the hyperfine interactions arising from 165Ho (I=7/2) with a natural abundance of 100 %.
In recent years a blossoming interest in the synthesis, photophysics and application of phosphorescent Pt(ii) complexes, particularly on their uses in bioimaging, photocatalysis and phosphorescent ...organic light-emitting diodes (OLEDs), has been witnessed. The superior performance of phosphorescent Pt(ii) complexes in these applications is linked to their diverse spectroscopic and photophysical properties, which can be systematically modulated by appropriate choices of auxiliary ligands. Meanwhile, an important criterion for the practical application of phosphorescent metal complexes is their stability which is crucial for biological utilization and industrial OLED applications. Taking both the luminescence properties and stability into consideration, chelating ligands having rigid scaffolds and with strong σ-donor atoms are advantageous for the construction of highly robust phosphorescent Pt(ii) complexes. The square-planar coordination geometry endows Pt(ii) complexes with the intriguing spectroscopic and photophysical properties associated with their intermolecular interactions in both the ground and excited states. In this article, we discuss the design and synthesis of phosphorescent Pt(ii) complexes with elaboration on the effects of ligands on the structure and luminescence properties. Based on their photophysical and emission properties, we intend to shed light on the great promise of highly robust phosphorescent Pt(ii) emitters in an array of applications from molecular materials to biosensors.
A systematic interrogation of male germ cells is key to complete understanding of molecular mechanisms governing spermatogenesis and the development of new strategies for infertility therapies and ...male contraception. Here we develop an approach to purify all types of homogeneous spermatogenic cells by combining transgenic labeling and synchronization of the cycle of the seminiferous epithelium, and subsequent single-cell RNA-sequencing. We reveal extensive and previously uncharacterized dynamic processes and molecular signatures in gene expression, as well as specific patterns of alternative splicing, and novel regulators for specific stages of male germ cell development. Our transcriptomics analyses led us to discover discriminative markers for isolating round spermatids at specific stages, and different embryo developmental potentials between early and late stage spermatids, providing evidence that maturation of round spermatids impacts on embryo development. This work provides valuable insights into mammalian spermatogenesis, and a comprehensive resource for future studies towards the complete elucidation of gametogenesis.
Materials with hysteretic multi‐step spin‐crossover (SCO) have potential application in high‐order data storage. Here, an unprecedented hysteretic four‐step SCO behavior with the sequence of ...LS↔HS0.25LS0.75↔HS0.5LS0.5↔ HS0.75LS0.25↔HS is found in a three‐dimensional (3D) Hofmann‐type metal–organic framework (MOF), which is evidenced by magnetic, differential scanning calorimetry, and crystal data. Further experiments involving guest exchange leads to the first reversible modulation of four‐, two‐, and one‐stepped SCO behaviors, which provides a new strategy for developing multi‐step SCO materials.
Hysteretic four‐step SCO behavior, LS↔HS0.25LS0.75↔HS0.5LS0.5↔HS0.75LS0.25↔HS, is evidenced by magnetic, differential scanning calorimetry, and crystal data. Furthermore, reversible modulation of four‐, two‐, and one‐stepped SCO behaviors is realized through guest exchange.
Reduction of the uranium(III) metallocene (η5‐C5iPr5)2UI (1) with potassium graphite produces the “second‐generation” uranocene (η5‐C5iPr5)2U (2), which contains uranium in the formal divalent ...oxidation state. The geometry of 2 is that of a perfectly linear bis(cyclopentadienyl) sandwich complex, with the ground‐state valence electron configuration of uranium(II) revealed by electronic spectroscopy and density functional theory to be 5f3 6d1. Appreciable covalent contributions to the metal‐ligand bonds were determined from a computational study of 2, including participation from the uranium 5f and 6d orbitals. Whereas three unpaired electrons in 2 occupy orbitals with essentially pure 5f character, the fourth electron resides in an orbital defined by strong 7s‐6dz2
mixing.
A new generation: Reduction of the uranium(III) metallocene (η5‐C5iPr5)2UI with potassium graphite produces the “second‐generation” uranocene (η5‐C5iPr5)2U, which contains uranium in the formal divalent oxidation state. The geometry of (η5‐C5iPr5)2U is that of a perfectly linear bis(cyclopentadienyl) sandwich complex.
Display omitted
•Briefly state the design strategies for luminescent lanthanide single-molecule magnets (SMMs).•Systematically survey the recent advances of luminescent lanthanide SMMs.•Discuss the ...magneto-luminescent behavior for lanthanide SMMs.
Incorporation of two characters into one molecular entity is an effective way to afford bifunctional molecule-based materials. Lanthanides serve as a group of preferable objectives for the construction of luminescent single-molecule magnets (SMMs) due to their excellent performances in areas of SMM and luminescence for molecular materials, showing a great potential of applications in high-density data storage, quantum computing, light-emitting diodes, biofluorescence labelling, etc. This review concentrates on the design strategies for the construction of luminescent SMMs referring to the organic chromophores and transition metal-containing chromophores as the antennas, as well as the recent examples of luminescent SMMs. To investigate the magneto-luminescent behavior (including the magneto-luminescent coupling), a few of classical complexes are discussed in the review to emphasize the importance of studying the correlation/coupling between relaxation mechanism and luminescence for lanthanide SMMs.
Antibodies are an important component in host immune responses to viral pathogens. Because of their unique maturation process, antibodies can evolve to be highly specific to viral antigens. ...Physicians and researchers have been relying on such high specificity in their quest to understand host-viral interaction and viral pathogenesis mechanisms and to find potential cures for viral infection and disease. With more than 60 recombinant monoclonal antibodies developed for human use in the last 20 years, monoclonal antibodies are now considered a viable therapeutic modality for infectious disease targets, including newly emerging viral pathogens such as Ebola representing heightened public health concerns, as well as pathogens that have long been known, such as human cytomegalovirus. Here, we summarize some recent advances in identification and characterization of monoclonal antibodies suitable as drug candidates for clinical evaluation, and review some promising candidates in the development pipeline.
PDF
