Here we reported the deuteration of the metal‐binding equatorial water molecules in a reported HoIII single‐molecule magnet (SMM) with pentagonal‐bipyramidal geometry, from Ho(CyPh2PO)2(H2O)53+ to ...Ho(CyPh2PO)2(D2O)53+. The hyperfine structures originating from the nuclear spin of 165HoIII can be clearly observed. Moreover, the resulting magnetization dynamics revealed the switch of the relative relaxation rates for the two isotope‐isomorphic complexes—respectively faster/slower at low/high temperature. The noticeable isotope effect arises from not only the paramagnetic metal center but also the diamagnetic ligands, which can be explained by the ab initio calculated tunnel splitting and the involvement of the super‐hyperfine interaction related to the difference in the nuclear spin number of protium (1H, I=1/2) and deuterium (2H, I=1).
We reported the nuclear‐spin driven magnetization dynamics involving both metal ion and the ligand, for first time, in two HoIII isomorphic single‐molecule magnets, where the behavior is originated from the super‐hyperfine interaction related to the difference in nuclear spin number of protium (I=1/2) and deuterium (I=1).
Single-molecule magnets (SMMs) are regarded as a class of promising materials for spintronic and ultrahigh-density storage devices. Tuning the magnetic dynamics of single-molecule magnets is a ...crucial challenge for chemists. Lanthanide ions are not only highly magnetically anisotropic but also highly sensitive to the changes in the coordination environments. We developed a feasible approach to understand parts of the magneto-structure correlations and propose to regulate the relaxation behaviors via rational design. A series of Co(II)-Dy(III)-Co(II) complexes were obtained using in situ synthesis; in this system of complexes, the relaxation dynamics can be greatly improved, accompanied with desolvation, via single-crystal to single-crystal transformation. The effective energy barrier can be increased from 293 cm(-1) (422 K) to 416 cm(-1) (600 K), and the tunneling relaxation time can be grown from 8.5 × 10(-4) s to 7.4 × 10(-2) s. These remarkable improvements are due to the change in the coordination environments of Dy(III) and Co(II). Ab initio calculations were performed to better understand the magnetic dynamics.
Abstract
A flame retardant coating was designed and synthesized using phenolic resin (PF), 9,10‐dihydro‐9‐oxa‐10‐phosphazephenanthrene‐10‐oxide (DOPO), and nano‐SiO
2
as raw materials. The coating is ...applied to the surface of rigid polyurethane foam (RPUF) to give it a flame retardant effect. Based on the excellent adhesion of PF, the coating effectively suppresses heat transfer, and the synergistic effect of DOPO and nano‐SiO
2
improves the flame retardancy of RPUF. In addition, vertical combustion experiments have shown that when the ratio of DOPO to nano‐SiO
2
is 2:1, there is no dripping, the flame is self‐extinguishing, and the internal structure remains basically unchanged, resulting in the best flame retardant effect. The cone calorimetric test shows that the coating can effectively reduce the total heat release and heat release rate of the substrate, and the smoke release rate and total smoke release data show that its smoke suppression effect is significantly improved. Thermogravimetric analysis shows that the coating can effectively improve the residual carbon rate of RPUF, and its mechanical properties are good. This study confirms that coatings based on PF/DOPO/Nano‐SiO
2
can effectively improve the flame retardancy of RPUF, providing a potential direction for the development of green insulation materials.
High Efficiency Sky‐Blue Gold(III)‐TADF Emitters Zhou, Dongling; Cheng, Gang; Tong, Glenna So Ming ...
Chemistry : a European journal,
December 1, 2020, Letnik:
26, Številka:
67
Journal Article
Recenzirano
Highly efficient sky‐blue luminescent gold(III) complexes with emission quantum yields up to 82 %, lifetimes down to 0.67 μs and emission peak maxima at 470–484 nm were prepared through a ...consideration of pincer gold(III) donor–acceptor complexes. Photophysical studies and time‐dependent density functional theory (TDDFT) calculations revealed that the emission nature of these gold(III) complexes is most consistent with TADF. Solution‐processed OLEDs with these gold(III) complexes as dopants afforded electroluminescence maxima at 465–473 nm with FWHM of 64–67 nm and maximum external quantum efficiencies (EQEs) of up to 15.25 %. This research demonstrates the first example of gold(III)‐OLEDs showing electroluminescence maxima at smaller than 470 nm, and highlights the potential of using gold(III)‐TADF emitters in the development of high efficiency blue OLEDs and blue emissive dopant in WOLEDs.
Sky‐blue emissive arylgold(III)‐TADF (thermally activated delayed fluorescence) complexes with emission maxima at 470–484 nm, Φ of up to 82 % and τ < 1 μs were successfully developed through a strategic consideration of substituent effects on the pincer C^N^C ligands and triphenylamine donor. Sky‐blue emitting OLEDs have been achieved with these gold(III)‐TADF emitters, showing high EQEs of up to 15.25 %, narrow‐band emission and good color purity with CIE coordinates of (0.16, 0.23).
Chemical modification with foreign atoms is a leading strategy to intrinsically modify the properties of host materials. Among them, potassium (K) modification plays a critical role in adjusting the ...electronic properties of carbon materials. Graphene, a true 2D carbon material, has shown fascinating applications in electrochemical sensing and biosensing. In this work, a facile and mild strategy to K‐modifying in graphene at room‐temperature is reported for the first time. X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectra, and cyclic voltammetry are used to characterize this K‐modified graphene. The K‐modified graphene is capable of acting as an electron transfer medium and more efficiently promotes charge transfer than unmodified graphene. A highly sensitive and stable amperometric sensor based on its excellent electrocatalytic activity toward the oxidation of NO2− is proposed. The sensor shows a linear range from 0.5 μM to 7.8 mM with a detection limit of 0.2 μM at a signal‐to‐noise ratio of 3. The modified electrode has excellent analytical performance and can be successfully applied in the determination of NO2− released from liver cancer and leukemia cells and shows good application potential in biological systems.
A facile and mild strategy to synthesize K‐modified graphene using the room‐temperature chemical modification of K in the graphene is demonstrated. The as‐prepared K‐modified graphene, used as an advanced electrode material, exhibits excellent electrocatalytic activity toward the oxidation of NO2− and is successfully applied in the determination of NO2− in vitro and from cancer cells.
Spin crossover (SCO) materials with new architectures will expand and enrich the research in the SCO field. Here, we report two metal–organic frameworks (MOFs) containing tetradentate organic ligands ...and hexatopic linkers Ag8X8(CN)66− (X=Br and I), which represents the first SCO MOF with clusters as building blocks. The silver halide cluster can be further removed after reacting with lithium tetracyanoquinodimethan (LiTCNQ). Such post‐synthetic modification (PSM) is realized via single‐crystal to single‐crystal (SCSC) transformation from urk to nbo topology. Accordingly, the spin state and fluorescence properties are greatly modified by cluster deconstruction. Therefore, these achievements will provide new ideas for the design of new SCO systems and the development of PSM methods.
Spin crossover metal–organic frameworks containing clusters as secondary building units are firstly realized, in which the clusters can be further removed via the post‐synthetic modification.
Spermatogenesis is a differentiation process during which diploid spermatogonial stem cells (SSCs) produce haploid spermatozoa. This highly specialized process is precisely controlled at the ...transcriptional, posttranscriptional, and translational levels. Here we report that N
-methyladenosine (m
A), an epitranscriptomic mark regulating gene expression, plays essential roles during spermatogenesis. We present comprehensive m
A mRNA methylomes of mouse spermatogenic cells from five developmental stages: undifferentiated spermatogonia, type A
spermatogonia, preleptotene spermatocytes, pachytene/diplotene spermatocytes, and round spermatids. Germ cell-specific inactivation of the m
A RNA methyltransferase Mettl3 or Mettl14 with Vasa-Cre causes loss of m
A and depletion of SSCs. m
A depletion dysregulates translation of transcripts that are required for SSC proliferation/differentiation. Combined deletion of Mettl3 and Mettl14 in advanced germ cells with Stra8-GFPCre disrupts spermiogenesis, whereas mice with single deletion of either Mettl3 or Mettl14 in advanced germ cells show normal spermatogenesis. The spermatids from double-mutant mice exhibit impaired translation of haploid-specific genes that are essential for spermiogenesis. This study highlights crucial roles of mRNA m
A modification in germline development, potentially ensuring coordinated translation at different stages of spermatogenesis.
The development of the musculoskeletal system is a complex process that involves very precise control of bone formation and growth as well as remodeling during postnatal life. Although the ...understanding of the transcriptional mechanisms of osteogenesis has increased considerably, the molecular regulatory basis, especially the gene regulatory network of osteogenic differentiation, is still poorly understood. This review provides the reader with an overview of the key transcription factors that govern bone formation, highlighting their function and regulation linked to Runt-related transcription factor 2 (Runx2). Runx2 as the master transcription factor of osteoblast differentiation, Twist, Msh homeobox 2 (Msx2), and promyelocytic leukemia zinc-finger protein (PLZF) acting upstream of Runx2, Osterix (Osx) acting downstream of Runx2, and activating transcription factor 4 (ATF4) and zinc-finger protein 521 (ZFP521) acting as cofactors of Runx2 are discussed, and their relevance for tissue engineering is presented. References are provided for more in-depth personal study.
This review provides an overview on the crystal structures and properties of metal carboxylate coordination compounds with 2,2′-bipyridyl-like ligands reported in the past 4 years, which exhibit ...interesting structural features. This covers coordination polymers in one, two and three dimensions, as well as molecular architectures assembled by hydrogen-bonding and/or π–π stacking interactions from low-dimensional entities to higher-dimensional supramolecular architectures.
This study tackles the persistent prognostic and management challenges of clear cell renal cell carcinoma (ccRCC), despite advancements in multimodal therapies. Focusing on anoikis, a critical form ...of programmed cell death in tumor progression and metastasis, we investigated its resistance in cancer evolution. Using single-cell RNA sequencing from seven ccRCC patients, we assessed the impact of anoikis-related genes (ARGs) and identified differentially expressed genes (DEGs) in Anoikis-related epithelial subclusters (ARESs). Additionally, six ccRCC RNA microarray datasets from the GEO database were analyzed for robust DEGs. A novel risk prognostic model was developed through LASSO and multivariate Cox regression, validated using BEST, ULCAN, and RT-PCR. The study included functional enrichment, immune infiltration analysis in the tumor microenvironment (TME), and drug sensitivity assessments, leading to a predictive nomogram integrating clinical parameters. Results highlighted dynamic ARG expression patterns and enhanced intercellular interactions in ARESs, with significant KEGG pathway enrichment in MYC + Epithelial subclusters indicating enhanced anoikis resistance. Additionally, all ARESs were identified in the spatial context, and their locational relationships were explored. Three key prognostic genes-TIMP1, PECAM1, and CDKN1A-were identified, with the high-risk group showing greater immune infiltration and anoikis resistance, linked to poorer prognosis. This study offers a novel ccRCC risk signature, providing innovative approaches for patient management, prognosis, and personalized treatment.
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