Al8 Cluster-Based Metal Halide Frameworks: Balancing Singlet-Triplet Excited States to Achieve White Light and Multicolor Luminescence.

Luminescent metal clusters have attracted great interest in current research; however, the design synthesis of Al clusters with color-tunable luminescence remains challenging. Herein, an [Al8 (OH)8 (NA)16 ] (Al8 , HNA = nicotinic acid) molecular cluster with dual luminescence properties of fluorescence and room-temperature phosphorescence (RTP) is synthesized by choosing HNA ligand as phosphor. Its prompt photoluminescence (PL) spectrum exhibits approximately white light emission at room temperature. Considering that halogen atoms can be used to regulate the RTP property by balancing the singlet and triplet excitons, different CdX2 (X- = Cl- , Br- , I- ) are introduced into the reactive system of the Al8 cluster, and three new Al8 cluster-based metal-organic frameworks, {[Al8 Cd3 Cl5 (OH)8 (NA)17 H2 O]·2HNA}n (CdCl2 -Al8 ), {[Al8 Cd4 Br7 (OH)8 (NA)16 CH3 CN]·NA·HNA}n (CdBr2 -Al8 ) and {[Al8 Cd8 I16 (OH)8 (NA)16 ]}n (CdI2 -Al8 ) are successfully obtained. They realize the color tunability from blue to yellow at room temperature. The origination of fluorescence and phosphorescence has also been illustrated by structure-property analysis and theoretical calculation. This work provides new insights into the design of multicolor luminescent metal cluster-based materials and develops advanced photo-functional materials for multicolor display, anti-counterfeiting, and encryption applications.

Halogen Engineering Strategy-Induced Color-Tunable Room Temperature Phosphorescence in Metal-Organic Halides.

Color-tunable room temperature phosphorescence (RTP) materials possess potential applications in multicolor imaging, multichannel anticounterfeiting, and information encryption. Herein, we synthesized two zero-dimensional cadmium-organic halides, (H-aepy)2CdX4 (referred to as CdX-aepy; X = Cl-, Br-; aepy = 3-(2-aminoethyl)pyridine), both of which exhibit long-lived excitation wavelength- and time-dependent RTP. Experimental and theoretical results suggest that the multicolor RTP can be ascribed to the coemission of pristine H-aepy ligands and halogen-affected H-aepys, supporting that suitably introducing halogens can be an efficient strategy for constructing multicolor RTP materials. Additionally, we also demonstrate that the two phosphors can be applied in multichannel anticounterfeiting and information encryption. This work reports two hybrids with color-tunable RTP, as well as provides new insight into the effect of halogens on the regulation of RTP.

Dual-Template-Directed Zero-Dimensional Bismuth Chlorides: Structures, Luminescence, Photoinduced Chromism, and Enhanced Proton Conductivity.

Zero-dimensional (0D) hybrid organic-inorganic bismuth halides have attracted immense scientific interest as promising candidates for lead-free materials. Here, by using a typical solvothermal method, two mixed-cation-phase 0D hybrid bismuth chlorides of [HPDA][H2PDA]BiCl6 (1) and [Hbzim][H2PA]BiCl6 (2) (PDA = bis(4-pyridyl)amine, bzim = benzimidazole, PA = 2-picolylamine) have been assembled based on a series of organic amine guests. Both compounds exhibit interesting photoluminescence phenomena, in which compound 1 exhibits a double emission property of blue fluorescence and yellow-green phosphorescence simultaneously, while compound 2 exhibits wide-band yellow-green emission under visible light excitation. The luminescence mechanism is explained by experiments and theoretical calculations. In view of the fact that halometallate units and the conjugated nitrogen heterocyclic systems can act as electron donors and electron acceptors, respectively, both compounds exhibit free radical-driven photochromism induced by electron transfer under xenon lamp irradiation at room temperature. In addition, benefiting from abundant hydrogen bond networks in structures, the two compounds show significant temperature-dependent proton conduction behavior in the range of 298-343 K, and the proton conductivity of both compounds is significantly improved after light irradiation. Our study demonstrates two novel hybrid mixed-cation-phase 0D hybrid bismuth halides with photoluminescence, photochromism, and photomodulated proton conduction properties, which enriches the dual-template-directed metal halide system and provides a feasible scheme for the synthesis of photoresponsive smart materials.

Light/Force-Responsive Room Temperature Phosphorescence in a Zinc-Organic Coordination Polymer.

A zinc-organic hybrid (1) with multifunctional room temperature phosphorescence (RTP) was synthesized. 1 presents light/force-sensitive RTP properties due to the photochromic behavior from gray to light yellow and the transition from crystalline to amorphous state, respectively. Furthermore, inkless printing and information encryption models were successfully constructed to prove their widespread application prospect.

Leveraging Crystalline and Amorphous States of a Metal-Organic Complex for Transformation of the Photosalient Effect and Positive-Negative Photochromism.

Uncovering differences between crystalline and amorphous states in molecular solids would both promote the understanding of their structure-property relationships, as well as inform development of multi-functional materials based on the same compound. Herein, for the first time, we report an approach to leverage crystalline and amorphous states of a zero-dimensional metal-organic complex, which exhibited negative and positive photochromism, due to the competitive chemical routes between photocycloaddition and photogenerated radicals. Furthermore, different polymorphs lead to the on/off toggling of photo-burst movement (photosalient effect), indicating the controllable light-mechanical conversion. Three demos were further constructed to support their application in information encryption and anti-counterfeiting. This work provides the proof-of-concept of a state- and polymorph-dependent photochemical route, paving an effective way for the design of new dynamically responsive systems.

Metal-Halide Coordination Polymers with Excitation Wavelength- and Time-Dependent Ultralong Room-Temperature Phosphorescence.

Metal-organic hybrids with ultralong room-temperature phosphorescence (RTP) have potential applications in many fields, including optical communications, anticounterfeiting, encryption, bioimaging, and so on. Herein, we report two isostructural one-dimensional zinc-organic halides as coordination polymers ZnX2(bpp) (X = Cl, 1; Br, 2; bpp = 1,3-di(4-pyridyl)propane) with excitation wavelength- and time-dependent ultralong RTP properties. The dynamic multicolor afterglow can be assigned to the emission of the pristine ligand bpp and its interactions with halogen atoms. Experiments and theoretical calculations both suggest that ZnX2 is crucial for ultralong RTP: (a) the metal coordination and X...π bonds in coordination polymers fix the bpp molecules and suppress the nonradiative transitions; (b) the spin-orbital coupling of coordination polymers is largely enhanced relative to the bpp because of the heavy atom effect; and (c) the charge transfer exists between halogens and bpp ligand. Therefore, this work not only presents metal-halide coordination polymers with excitation wavelength- and time-dependent RTP properties, but also provides a facile method for the new types of dynamic multicolor afterglow materials.

Dynamic Manipulating Space-Resolved Persistent Luminescence in Core-Shell MOFs Heterostructures via Reversible Photochromism.

Photo-controllable persistent luminescence at the single crystal level can be achieved by the integration of long-lived room temperature phosphorescence (RTP) and photochromism within metal-organic frameworks (MOFs) for the first time. Moreover, the multiblock core-shell heterojunctions have been prepared utilizing the isostructural MOFs through an epitaxial growth process, in which the shell exhibits bright yellow afterglow emission that gradually disappears upon further irradiation, but the core does not show such property. Benefitting from combined persistent luminescence and photochromic behavior, a multiple encryption demo can be facilely designed based on the dynamic manipulating RTP via reversible photochromism. This work not only develops new types of dynamically photo-controllable afterglow switch, but also provides a method to obtain MOFs-based optical heterojunctions towards potential space/time-resolved information encryption and anti-counterfeiting applications.

Manipulating On/Off Single-Molecule Magnet Behavior in a Dy(III)-Based Photochromic Complex.

Exploitation of room temperature (RT) photochromism and photomagnetism to induce single-molecule magnet (SMM) behavior has potential applications toward optical switches and magnetic memories, and remains a tremendous challenge in the development of new bulk magnets. Herein, a series of chain complexes [Ln3(H-HEDP)3(H2-HEDP)3]·2H3-TPT·H4-HEDP·10H2O (QDU-1; Ln = Dy (QDU-1(Dy)), Gd (QDU-1(Gd)), and Y (QDU-1(Y)); HEDP = hydroxyethylidene diphosphonate; TPT = 2,4,6-tri(4-pyridyl)-1,3,5-triazine) were synthesized by solvothermal reactions. All the compounds exhibited reversible photochromic and photomagnetic behaviors via UV light irradiation at RT, induced by the photogenerated radicals via a photoinduced electron transfer (PET) mechanism. More importantly, the PET process induced significant variations in magnetic interactions for the Dy(III) congener. Strong ferromagnetic coupling with remarkably slow magnetic relaxation without applied dc fields was observed between DyIII ions and photogenerated O• radicals, showing SMM behavior after RT illumination. For the first time, we observed the reversible RT photochromism and photomagnetism in the lanthanide-based materials. This work realized the radicals-actuated on/off SMM behavior via RT light irradiation, providing a new strategy for constructing the light-induced SMMs.

Optimizing the Proton Conductivity of Fe-Diphosphonates by Increasing the Relative Number of Protons and Carrier Densities.

Proton conductive materials have attracted extensive interest in recent years due to their fascinating applications in sensors, batteries, and proton exchange membrane fuel cells. Herein, two Fe-diphosphonate chains (H4-BAPEN)0.5·[FeIII(H-HEDP)(HEDP)0.5(H2O)] (1) and (H4-TETA)2·[FeIII2FeII(H-HEDP)2(HEDP)2(OH)2]·2H2O (2) (HEDP = 1-hydroxyethylidenediphosphonate, BAPEN = 1,2-bis(3-aminopropylamino)ethane, and TETA = triethylenetetramine) with different templating agents were prepared by hydrothermal reactions. The valence states of the Fe centers were demonstrated by 57Fe Mössbauer spectra at 100 K, with a high-spin FeIII state for 1 and mixed high-spin FeIII/FeII states for 2. Their magnetic properties were determined, which featured strong antiferromagnetic couplings in the chain. Importantly, the proton conductivity of both compounds at 100% relative humidity was explored at different temperatures, with 2.79 × 10-4 S cm-1 at 80 °C for 1 and 7.55 × 10-4 S cm-1 at 45 °C for 2, respectively. This work provides an opportunity for improving proton conductive properties by increasing the relative number of protons and the carrier density using protonated flexible aliphatic amines.

The trade-off anionic modulation in metal-organic glasses showing color-tunable persistent luminescence.

Ultralong room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) materials provide exciting opportunities for the rational design of persistent luminescence owing to their long-lived excitons. However, conventional rare-earth-based all-inorganic emitters involve high cost and harsh synthesis conditions, and purely organic systems may require complicated synthesis routes and tedious purification. Therefore, it is highly desirable to develop a cost-effective and easily manufacturable method for achieving color-tunable RTP-TADF with a long afterglow. Herein, we demonstrate a rational strategy to introduce different anions (Cl-, Br- and OAc- ions) into a Zn-based metal-organic scaffold, which can improve the crystal rigidity and achieve a well-balanced RTP-TADF. Both theoretical and experimental studies have demonstrated that the adjustment of different anions can effectively modulate the spin-orbit coupling (SOC) and the energy gap of singlet-triplet states (ΔEST) and then tailor the afterglow lifetime. Moreover, we prepared dye-doped metal-organic hybrid glasses with remarkable potential for the color-tunable afterglow. Therefore, this work not only provides a new horizon for modulating crystal and glass states with color/lifetime-tunable persistent luminescence, but also contributes to optical information storage and anti-counterfeiting technology.

A flexible ligand and halogen engineering enable one phosphor-based full-color persistent luminescence in hybrid perovskitoids.

Color-tunable room temperature phosphorescent (RTP) materials have raised wide interest due to their potential application in the fields of encryption and anti-counterfeiting. Herein, a series of CdX2-organic hybrid perovskitoids, (H-apim)CdX3 and (apim)CdX2 (denoted as CdX-apim1 and CdX-apim2, apim = 1-(3-aminopropyl)imidazole, X = Cl, Br), were synthesized using apim with both rigid and flexible groups as ligands, which exhibit naked-eye detectable RTP with different durations and colors (from cyan to red) by virtue of different halogen atoms, coordination modes and the coplanar configuration of flexible groups. Interestingly, CdCl-apim1 and CdX-apim2 both exhibit excitation wavelength-dependent RTP properties, which can be attributed to the multiple excitation of imidazole/apim, the diverse interactions with halogen atoms, and aggregated state of imidazoles. Structural analysis and theoretical calculations confirm that the aminopropyl groups in CdCl-apim1 do not participate in luminescence, while those in CdCl-apim2 are involved in luminescence including both metal/halogen to ligand charge transfer and twisted intramolecular charge transfer. Furthermore, we demonstrate that these perovskitoids can be applied in multi-step anti-counterfeiting, information encryption and smart ink fields. This work not only develops a new type of perovskitoid with full-color persistent luminescence, but also provides new insight into the effect of flexible ligands and halogen engineering on the wide-range modulation of RTP properties.

CO2-responsive tunable persistent luminescence in a hydrogen-bond organized two-component ionic crystal.

A reversible CO2-responsive luminescent material was constructed by a facile hydrogen-bond self-assembly of a two-component ionic crystal. The modification of CO2 on the ionic crystal not only alternates the green afterglow, but also endows the material with inverse excitation wavelength dependence for multicolor emission.

Quadruple Anticounterfeiting Encryption: Anion-Modulated Forward and Reverse Excitation-Dependent Multicolor Afterglow in Two-Component Ionic Crystals.

Molecule-based afterglow materials with ultralong-lived excited states have attracted great attention owing to their unique applications in light-emitting devices, information storage, and anticounterfeiting. Herein, a series of new types of two-component ionic crystalline materials were fabricated by the self-assembly of cytosine and different anions under ambient conditions. The multiple intermolecular interactions of cytosine with phosphate and halogens anions can lead to abundant energy levels and different crystal stacking modes to control molecular aggregation and excited-state intermolecular proton transfer (ESIPT) process. Interestingly, H-aggregation-induced green to yellow room-temperature phosphorescence (RTP) and ESIPT-dominated cyan RTP to deep blue thermally activated delayed fluorescence (TADF) emission can be generated by tuning excitation wavelength, time evolution, and temperature. Furthermore, the combination of two-component ionic crystals can be used as multicolored candidates for quadruple information encryption. Therefore, this work not only develops an anion-modulated strategy to achieve color-tunable afterglow from both static and dynamic fashions but also provides a guideline for designing forward/reverse excitation-dependent luminescent materials.

Multi-Mode and Dynamic Persistent Luminescence from Metal Cytosine Halides through Balancing Excited-State Proton Transfer.

Persistent luminescence has attracted great attention due to the unique applications in molecular imaging, photodynamic therapy, and information storage, among many others. However, tuning the dynamic persistent luminescence through molecular design and materials engineering remains a challenge. In this work, the first example of excitation-dependent persistent luminescence in a reverse mode for smart optical materials through tailoring the excited-state proton transfer process of metal cytosine halide hybrids is reported. This approach enables ultralong phosphorescence and thermally activated delayed fluorescence emission colors highly tuned by modulation of excitation wavelength, time evolution, and temperature, which realize multi-mode dynamic color adjustment from green to blue or cyan to yellow-green. At the single crystal level, the 2D excitation/space/time-resolved optical waveguides with triple color conversion have been constructed on the organic-metal halide microsheets, which represent a new strategy for multi-dimensional information encryption and optical logic gate applications.

[Detection of NPM1 Mutation in Acute Myeloid Leukemia by Droplet Digital PCR and Its Clinical Application Value].

OBJECTIVE: To establish the droplet digital PCR (ddPCR) assay for the detection of NPM1 type A mutation in patients with acute myeloid leukemia (AML), and to evaluate its specificity, sensitivity and its value in clinical application. METHODS: NPM1 mutant and wildtype plasmids were used to verify the performance of ddPCR. Both ddPCR and Sanger sequencing were used to detect the bone marrow samples of 87 AML patients, which were confirmed by next generation sequencing (NGS). Moreover, NPM1 mutation burden was dynamically monitored in five patients by ddPCR. RESULTS: The limit of blank (LOB) of ddPCR established for NPM1 mutation detection was 1.1 copies/µl, and the limit of detection (LOD) was 2.43 copies/µl, which had good linearity. Among the 87 newly diagnosed AML patients, ddPCR identified seventeen cases positive for NPM1 mutation (19.5%)， which was consistent with Sanger sequencing. NGS confirmed 12 positive cases, including 8 of type A mutations, 2 of type D mutations, and 2 of rare type mutations. The results of dynamic monitoring of NPM1 mutation burden in 5 patients showed that the NPM1 mutation burden decreased obviously even close to 0, when patients achieve complete remission after chemotherapy. However, the mutation burden was increased again at the time of relapse. CONCLUSION: In this study, we established a ddPCR method for detection of NPM1 mutation with good sensitivity and repeatability, which can be used for screening NPM1 mutation in newly diagnosed AML patients and for minimal residual disease monitoring after remission in positive AML patients to guide treatment.

Triple-mode tunable long-persistent luminescence in a 3D zinc-organic hybrid.

A 3D zinc-organic hybrid [Zn3(D-Cam)3(tib)2]·2H2O (1) exhibits triple-mode dependent (including excitation wavelength, time and temperature) long-persistent luminescence. Experimental and theoretical calculations support that the long lifetime and color-tunable afterglow may be due to the dispersive electronic state distribution. Furthermore, the hybrid is also used for optical anti-counterfeiting and information encryption applications.

[Research on remote sensing inversion biomass method based on the Suaeda salsa's measured spectrum].

Suaeda salsa is one of characteristic vegetation of wetlands in Northern China. By measuring the spectral data and leaf area index (LAI) of the Suaeda salsa in the ShuangTai Estuary of Liaodong Bay by the use of portable spectrometer and vegetation canopy analyzer, collecting the biomass of the Suaeda salsa samples, setting up the spectral reflectance curve of the Suaeda salsa, probing into the relationship between the vegetation index and the leaf area index of the Suaeda salsa, carrying out regression analysis of LAI and biomass and constructing the function equation, some conclusion were drawn: (1) By the end of September the spectral characteristics of Suaeda salsa show that at the red band 630 nm there is a clear reflection of the peak with a reflection rate of 12%-15%; there is a clear "red valley" configuration between 680 and 700 nm, and there is a clear "red edge" reflection rate of 25%-30% about 760 nm. (2) It was found that there is best correlation between vegetation index (SAVI and MSAVI) and LAI compared to other vegetation index in the regression analysis of the LAI and vegetation index. The correlation coefficient R2 is 0.711. By comparison of vegetation index linear regression equations, the correlation coefficient (SAVI and LADI) R2 is 0.696; the value of R2 (LAI and MSAV) is 0.695; the value of R2 (RVI) is 0.664; the value of R2(NDVI) is 0.649 and the value of R2 (PVI) is 0.466. (3) The value of correlation coefficient is low between the biomass and the vegetation indexes (RVI and NDVI) and the value of linear regression equation's R2 is 0.342 and 0.316, and the Logarithmic regression equation's R2 is 0.319 and 0.21, and the quadratic equation's R2 is 0.589 and 0.568, the value of correlation coefficient is high between the biomass and the vegetation indexes (PVI, SAVI and MSAVI), the value of linear regression equation is 0.626, 0.698 and 0.679, that of logarithmic regression equation is 0.592, 0.706 and 0.683 and that of the quadratic equation is 0.688, 0.711 and 0.683.

Zinc-diphosphonates with extended dipyridine units: synthesis, structures, in situ reactions, and photochromism.

Two zinc-diphosphonates formed from extended dipyridine units di-3,6-(4'-pyridyl)-1,2,4,5-tetrazine (dipytz) and 1,4-di(pyridine-4-yl)benzene (pbyb), [H2-Hdpt][Zn3(HEDP)2(H2O)]·2H2O (1) and [Zn2(HEDP)(pbyb)0.5(H2O)]·H2O (2) were solvothermally prepared (HEDP = 1-hydroxyethylidenediphosphonate, Hdpt = 1H-3,5-bis(4-pyridyl)-1,2,4-triazole). Compound 1 exhibits an anionic Zn-HEDP layer with protonated dipyridine fragments as the template. In 2, the HEDP ligands bridge Zn2+ ions to form neutral zincophosphonate layers as supramolecular building blocks (SBBs), which are further pillared by neutral pbyb moieties to generate the final 3D pillar-layer structure. Interestingly, in situ reactions have taken place in the formation of 1, and the starting material dipytz in situ transformed to Hdpt in the process of assembly and was captured in the resultant crystal. Although the structural constituents are non-photochromic, 2 features photochromic performance with a detectable color change from colorless to pink under the stimulus of UV light under ambient conditions. A reversible color change process has been realized via annealing the colored sample at 120 °C for half an hour or putting the colored sample in air for two hours.

Photochromism and photomagnetism in crystalline hybrid materials actuated by nonphotochromic units.

Two novel photochromic and photomagnetic complexes actuated by nonphotochromic ligands have been hydrothermally synthesized through the pillar-layer strategy. After Xe lamp irradiation at room temperature, compound 1 shows naked-eye detectable photochromism, while 2 exhibits an efficient photodemagnetization effect.

Bipyridine-triggered modulation of structure and properties of zinc-diphosphonates: coordination role vs. template rule.

Two zinc-diphosphonates driven by 4,4'-bipyridine (4,4'-bipy), [Zn4(HEDP)2(4,4'-bipy)2]·4.5(H2O) (1) and (H2-4,4'-bipy)0.5·[Zn3(HEDP)(H2EDP)(H2O)]·1.5(H2O) (2), were solvothermally prepared (HEDP = CH3C(OH)(PO3)2, 1-hydroxyethylidenediphosphonate). Compound 1 features a layered structure with the Zn-HEDP chains as supramolecular units and 4,4'-bipy as interchain linkers. Compound 2 possesses a Zn-HEDP layer with protonated 4,4'-bipy as template. The structure differences between the two compounds are mainly ascribed to the distinct role of 4,4'-bipy in the process of in situ assembly. In compound 1, the 4,4'-bipy moiety acts as coordinative unit to participate in the formation of the resulting architecture. However, in compound 2, the protonated 4,4'-bipy serves as template to direct the formation of the final structure. The luminescence and proton conduction of the two compounds were investigated. Compounds 1 and 2 exhibit intense blue fluorescence; compound 2 has a proton conductivity of 2.61 × 10-4 S cm-1 at 100% relative humidity and 70 °C.