Induced Absolute Configuration of Achiral Tetradentate Ligands in Metal–Organic Frameworks for Circularly Polarized Luminescence

The crystallization of chiral molecules is of great significance to understand the origin and evolution of hierarchical chirality and reveal the relationships between structural chirality and circularly polarized luminescence(CPL)activity.Here,we report two pairs of chiral metal–organic frameworks(MOFs)(DCF-17/LCF-17,DCF-18/LCF-18)by utilizing tetradentate ligands tetra(3-imidazoylphenyl)ethylene(TIPE)and 4,4'-[4',5'-bis[4-(4-pyridinyl)phenyl][1,1':2',1”-terphenyl]-4,4”-diyl]bis[pyridine](TPPP)as linkers.It can be observed that the spontaneous resolution of the achiral ligands is converted into the induced resolution,and the ligands form the absolute configuration by using enantiopure camphoric acid(cam)as chiral induced reagent(CIR).As a result,the racemate MOFs can be driven to generate absolute homochiral crystallization.Another two achiral MOFs[Cd(D-cam)(TPPP)_(0.5)](AF-1,AF=achiral framework)and[Cd(L-cam)(TPPP)_(0.5)](AF-2)were prepared.The position disorder of D/L-cam skeleton causes the generation of nonchiralization,further leading to disappearance of symmetry breaking of TPPP.For the perspective of structure,this is the first report which reveals the chiral transfer and nonchiralization between chiral induced agents and tetradentate ligands.Besides,DCF-17 and LCF-17 show CPL with luminescence dissymmetry factor(glum)of–1.0×10^(-2)and+9.2×10^(–3),respectively.This work provides the useful evidences to reveal the induced chiral crystallization and the construction of CPL-active crystalline materials.

Biomimetic Preparation of Alumina Hierarchical Papillary Microrough Structure for Hydrophobic Improvement and Its Abrasion Resistance Finite Element Analysis

The surface of lotus leaves has a hierarchical micro–nano-rough structure.We determined that the papillary structure also possesses hierarchical features on the microscale.We used alumina particles as rough structure building units to construct a Hierarchical Papillary microrough Structure(HPS)on a ceramic surface.The effects of the spatial distribution of HPS on the abrasion resistance and mechanical stability of hydrophobic coatings were investigated.Furthermore,for each HPS,the falling sand abrasion process was analyzed using finite element fluid mechanics analysis.A denser or more two-dimensional HPS implied that more area was impacted by the falling sand and that the abrasion amount and rate were higher.This is contrary to the common belief that when there are more wear-resistant substances on the surface,the abrasion resistance is better;thus,abrasion resistance does not necessarily depend entirely on the concentration of wear-resistant substances on the surface,but it is also influenced by the abrasion mode and the spatial distribution structure of the wear-resistant substances.The 3D stacked HPS(3D-HPS)with excellent abrasion resistance and rich pore structure considerably enhanced the mechanical stability of the hydrophobic coatings.These findings provide novel insights and a theoretical basis for designing spatial structures on high abrasion-resistant superhydrophobic ceramic surfaces.

A benzothiazole-based ratiometric fluorescent probe with large Stokes shifts for quantitative profiling of sulfite in real samples and living cells

Rapid,selective,and quantitative profiling of SO_(3)^(2-)is a prerequisite for investigating its effect on different physiopathological processes.To address this challenge,our team prepared a ratiometric fluorescent probe HBTCS,based on 4-(benzothiazol-2-yl)-3-hydroxybenzaldehyde for specific detection of SO_(3)^(2-)under a singlewavelength excitation.The solution of probe HBTC-S itself exhibited orange fluorescence(λ_(em)=614 nm),and became green fluorescent(λ_(em)=471 nm)after the addition of SO_(3)^(2-).The vitro experiments suggested that the probe displayed high sensitivity,excellent selectivity,and a low detection limit(0.15μM).Moreover,probe HBTC-S was successfully applied for qualitative and quantitative monitoring of SO_(3)^(2-)in realistic samples and living HeLa cells in a ratiometric manner.

Investigation on the Effect of the Multilayered Porous Structure of Sea Urchin Skeleton on Its Mechanical Behavior

In this paper,the effect of stereom structure on the mechanical behavior of the Sea Urchin Inorganic Skeleton(SUIS)has been studied.The stereom microstructure of both Anthocidaris crassispina and Tripnenstes gratilla was characterized by Scanning Electron Microscopy(SEM).Results indicate that a three-layer porous structure consisting of a growth,a support,and a resorption(GSR)layer is a common denominator for both species.The effect of GSR layer order on the mechanical behavior of the SUIS was studied by a finite element method.The results show that the GSR model could effectively reduce the maximum tensile stress on its meridional sutures under unidirectional pressure,hydrostatic pressure,and self-weight situation.For a fabricated three-layered ceramic test strips with different layer orders,the mechanical properties have a completely opposite performance compared with the compressive properties of the calculated SUIS-Iike models.This indicates that the GSR structure can effectively improve the mechanical properties of the SUIS,but it cannot be applied to bionics without considering its synergistic effect with the macro-structure of the SUIS.This is a typical example of bionic invalidation by single structure,where multi-level structure bionics may be an effective solution.

Cytarabine delivered by CD44 and bone targeting redox-sensitive liposomes for treatment of acute myelogenous leukemia

Acute myelogenous leukemia(AML)remains a serious fatal disease for the patients and effective treatment strategies are urgently needed.Based on the characteristics of the AML,we developed the CD44 and bone targeting liposomes delivery system decorated with the redox-cleavable polymer.First,ALN-HA was obtained by amination between alendronate(ALN)and hyaluronic acid(HA),and cholesterol(Chol)was coupled by a disulfide linker(-SS-)with biological reducibility to obtain the goal polymer,ALN-HA-SS-Chol,decorated the liposomes loaded with the Cytarabine(AraC).ALN-HA-SS-AraC-Lip exhibited a spherical morphology with the diameter of 117.5nm and expanded at the environment of 10mM dithiothreitol.Besides,compared with other groups,ALN-HA-SS-AraC-Lip showed benign hydroxyapatite affinity in vitro and bone targeting in C57/BL6 mice,also,ALN-HA-SS-AraC-Lip exhibited encouraging antitumor which significantly reduced the white blood cell amount in bone marrow and blood smear caused by AML model,besides,the dual targeting liposomes also prolong the survival time of mice.In conclusion,the bone and CD44 dual targeting liposomes with redox sensitivity could target to the leukemia stem cells regions and then uptake by the tumor cells,which would be a valuable target for the treatment of the AML.