Reversible Transfer Research Articles

Dynamic Assembly‐Induced Time‐Resolved Optical Switches for Rewritable Advanced Information Encryption

AbstractThe development of photocontrolled assembly of smart materials with time‐dependent optical characteristics is a promising strategy to fabricate multiple optical materials for advanced information encryption. Herein, this work reports the integration of photochoromic spiropyran and square‐planar platinum(II) as a photocontrolled switching motif that endows the materials with dynamic assembly‐induced optical characteristics. Importantly, the time‐resolved multilevel optical switching processes have been achieved based on the synergism of the reversible photochoromism and fluorescence resonance energy transfer (FRET) processes through regulating the intramolecular isomerization and intermolecular self‐assembly processes. The excellent temporal multicolor features promote the photocontrolled switches as a promising candidate for time‐resolved confidential materials including multilevel displays and dynamic 4 dimension (4D) codes, with the achievement of relative encrypted data that can only be identified at a specified time. This synergistical strategy for constructing advanced materials provides an inspiring guidance for information encryption with higher security requirements.

Piezochromism and Conductivity Modulations under High Pressure by Manipulating the Viologen Radical Concentration.

Manipulating the radical concentration to modulate the properties in solid multifunctional materials is an attractive topic in various frontier fields. Viologens have the unique redox capability to generate radical states through reversible electron transfer (ET) under external stimuli. Herein, taking the viologens as the model, two kinds of crystalline compounds with different molecule-conjugated systems were designed and synthesized. By subjecting the specific model viologens to pressure, the cross-conjugated 2-X all exhibit much higher radical concentrations, along with more sensitive piezochromic behaviors, compared to the linear-conjugated 1-X. Unexpectedly, we find that the electrical resistance (R) of 1-NO3 decreased by three orders of magnitude with the increasing pressure, while that in high-radical-concentration 2-NO3 remained almost unchanged. To date, such unusual invariant conductivity has not been documented in molecular-based materials under high pressure, breaking the conventional wisdom that the generations of radicals are beneficial to improve conductivity. We highlight that adjusting the molecular conjugation modes can be used as an effective way to regulate the radical concentrations and thus modulate properties rationally.

Efficient and Selective Photogeneration of Stable N-Centered Radicals via Controllable Charge Carrier Imbalance in Cesium Lead Halide Nanocrystals.

Despite the versatility of semiconductor nanocrystals (NCs) in photoinduced chemical processes, the generation of stable radicals has been more challenging due to reverse charge transfer or charge recombination even in the presence of sacrificial charge acceptors. Here, we show that cesium lead halide (CsPbX3) NCs can selectively photogenerate either aminium or aminyl radicals from amines, taking advantage of the controllable imbalance of the electron and hole populations achieved by varying the solvent composition. Using dihalomethane as the solvent, irreversible removal of the electrons from CsPbX3 NCs enabled by the photoinduced halide exchange between the NCs and the dihalomethane resulted in efficient oxidative generation of the aminium radical. In the absence of dihalomethane in solvent, the availability of both electrons and holes resulted in the production of an aminyl radical via sequential hole transfer and reductive N-H bond dissociation. The negative charge of the halide ions on the NC's lattice surface appears to facilitate the aminyl radical production, competing favorably with the reversible charge transfer reverting to the reactant.

Controllable synthesis of diazocine - investigation on electroreduction mechanism for intramolecular cyclization of 2,2′- dinitrodibenzyl in the presence of CO2

11,12-dihydrodibenzo[c,g][1,2]diazocine (Diazocine, 12), a molecular switch capable of reversible interconversion between (at least) two states by light, has been widely used in pharmacology and biochemistry. However, most of the synthetic methods so far have been limited by tedious steps, complicated derivatives, and long reaction times, resulting in poor synthetic yields of 12. Here, we propose a green, effective, and controllable strategy for synthesizing 12. The intramolecular cyclization (8-membered ring) of 2,2′-dinitrodibenzyl (1) was achieved by electrochemical reduction in the presence of CO2, and 12 and its derivatives 11,12-dihydrodibenzo[c,g][1,2]diazocine-N-oxide (DDCG-N, 11) were synthesized. The electrochemical reduction mechanism of 1 in the presence of CO2 was investigated by cyclic voltammetry (CV) and in situ FT-IR spectroelectrochemistry. The molecular structures of the electrolytic product (12) and intermediate (11) were confirmed by single-crystal X-ray diffraction, NMR, and MS. The results show that the electrochemical behavior of 1 in acetonitrile (AN) changes from a reversible two-step 1-electron transfer process (in the absence of CO2) to an irreversible 8-electron transfer process (in the presence of CO2). The 12 and 11 can be obtained by controlling the electrolytic potential and time. Under the optimum conditions, the yields of 12 and 11 were 84% and 71%, respectively.

NAD(P) transhydrogenase isoform distribution provides insight into apicomplexan evolution.

Membrane-located NAD(P) transhydrogenase (NTH) catalyses reversible hydride ion transfer between NAD(H) and NADP(H), simultaneously translocating a proton across the membrane. The enzyme is structurally conserved across prokaryotes and eukaryotes. In heterotrophic bacteria NTH proteins reside in the cytoplasmic membrane, whereas in animals they localise in the mitochondrial inner membrane. Eukaryotic NTH proteins exists in two distinct configurations (isoforms) and have non-mitochondrial functions in unicellular eukaryotes like Plasmodium, the causative agent of malaria. In this study, we carried out a systematic analysis of nth genes across eukaryotic life to determine its prevalence and distribution of isoforms. The results reveal that NTH is found across all major lineages, but that some organisms, notably plants, lack nth genes altogether. Isoform distribution and phylogenetic analysis reveals different nth gene loss scenarios in apicomplexan lineages, which sheds new light on the evolution of the Piroplasmida and Eimeriidae.

Versatile Production of Multivariate, Hyperdimensional End Group and Main Chain Functionalized Polyolefins.

The (stereoselective) living coordinative copolymerization of 1-alkenes with 4-aryl-1,6-heptadienes, in both the absence and presence of multiple equivalents of a reversible chain transfer agent, is established as a highly versatile strategy for production of multivariate hyperdimensional functionalized semi-crystalline or amorphous polyolefins that optionally possess either mono- or difunctionalized (telechelic) end-groups in combination with a programmable level of incorporation of orthogonal functional groups within the main-chain. The non-conjugated diene comonomers are readily obtained from a diverse range of aryl carboxaldehyde precursors through a one-step bis-allylation process. These results serve to provide a new platform for exploring the science and technology of a vast new landscape of functionalized classes of polyolefins that are now accessible in practical and scalable quantities.

Reversible Intramolecular Proton Transfer in Curcumin Crystals and Nonlinear Size Correlation

Intramolecular proton transfer is more difficult for curcumin in the solid state than in the solution. In this study, a reversible transformation of keto-enol to the β-diketone form of curcumin was achieved by nonchemical methods. The obstacle to intramolecular proton transfer was shown to be the intermolecular hydrogen bond at the keto-enol linkage. When the intermolecular hydrogen bond in the keto-enol site of the curcumin molecule is broken, reversible proton transfer will occur more easily. The energy fluctuations and vibrational shifts in the functional group spectra were captured during the proton transfer and conformational rearrangement with increasing temperature (from 170 to 183 °C) after desolvation. The maximum energy change in the proton transfer process of curcumin occurs in the 200 μm crystal (extreme value point), influenced by the combination of the specific surface area of the crystal itself and the degree of thermal homogeneity. This paper presents an environmentally friendly and efficient method to regulate the physicochemical properties of solid organic materials.

Versatile Production of Multivariate, Hyperdimensional End Group and Main Chain Functionalized Polyolefins

AbstractThe (stereoselective) living coordinative copolymerization of 1‐alkenes with 4‐aryl‐1,6‐heptadienes, in both the absence and presence of multiple equivalents of a reversible chain transfer agent, is established as a highly versatile strategy for production of multivariate hyperdimensional functionalized semi‐crystalline or amorphous polyolefins that optionally possess either mono‐ or difunctionalized (telechelic) end‐groups in combination with a programmable level of incorporation of orthogonal functional groups within the main‐chain. The non‐conjugated diene comonomers are readily obtained from a diverse range of aryl carboxaldehyde precursors through a one‐step bis‐allylation process. These results serve to provide a new platform for exploring the science and technology of a vast new landscape of functionalized classes of polyolefins that are now accessible in practical and scalable quantities.

Weak, Broken, but Working-Intramolecular Hydrogen Bond in 2,2'-bipyridine.

From an academic and practical point of view, it is desirable to be able to assess the possibility of the proton exchange of a given molecular system just by knowing the positions of the proton acceptor and the proton donor. This study addresses the difference between intramolecular hydrogen bonds in 2,2'-bipyridinium and 1,10-phenanthrolinium. Solid-state 15N NMR and model calculations show that these hydrogen bonds are weak; their energies are 25 kJ/mol and 15 kJ/mol, respectively. Neither these hydrogen bonds nor N-H stretches can be responsible for the fast reversible proton transfer observed for 2,2'-bipyridinium in a polar solvent down to 115 K. This process must have been caused by an external force, which was a fluctuating electric field present in the solution. However, these hydrogen bonds are the grain that tips the scales precisely because they are an integral part of a large system of interactions, including both intramolecular interactions and environmental influence.

Cations impact radical reaction dynamics in concentrated multicomponent aqueous solutions.

Ultraviolet (UV) photolysis of nitrite ions (NO2-) in aqueous solutions produces a suite of radicals, viz., NO·, O-, ·OH, and ·NO2. The O- and NO· radicals are initially formed from the dissociation of photoexcited NO2-. The O- radical undergoes reversible proton transfer with water to generate ·OH. Both ·OH and O- oxidize the NO2- to ·NO2 radicals. The reactions of ·OH occur at solution diffusion limits, which are influenced by the nature of the dissolved cations and anions. Here, we systematically varied the alkali metal cation, spanning the range from strongly to weakly hydrating ions, and measured the production of NO·, ·OH, and ·NO2 radicals during UV photolysis of alkaline nitrite solutions using electron paramagnetic resonance spectroscopy with nitromethane spin trapping. Comparing the data for the different alkali cations revealed that the nature of the cation had a significant effect on production of all three radical species. Radical production was inhibited in solutions with high charge density cations, e.g., lithium, and promoted in solutions containing low charge density cations, e.g., cesium. Through complementary investigations with multinuclear single pulse direct excitation nuclear magnetic resonance (NMR) spectroscopy and pulsed field gradient NMR diffusometry, cation-controlled solution structures and extent of NO2- solvation were determined to alter the initial yields of ·NO and ·OH radicals as well as alter the reactivity of NO2- toward ·OH, impacting the production of ·NO2. The implications of these results for the retrieval and processing of low-water, highly alkaline solutions that comprise legacy radioactive waste are discussed.

RAFT Synthesis and Characterization of Poly(Butyl-co-2-(N,N-Dimethylamino)Ethyl Acrylates)-block-Poly(Polyethylene Glycol Monomethyl Ether Acrylate) as a Photosensitizer Carrier for Photodynamic Therapy.

Polymer micelles are promising drug delivery systems for highly hydrophobic photosensitizers in photodynamic therapy (PDT) applications. We previously developed pH-responsive polymer micelles consisting of poly(styrene-co-2-(N,N-dimethylamino)ethyl acrylate)-block-poly(polyethylene glycol monomethyl ether acrylate) (P(St-co-DMAEA)-b-PPEGA) for zinc phthalocyanine (ZnPc) delivery. In this study, poly(butyl-co-2-(N,N-dimethylamino)ethyl acrylates)-block-poly(polyethylene glycol monomethyl ether acrylate) (P(BA-co-DMAEA)-b-PPEGA) was synthesized via reversible addition and fragmentation chain transfer (RAFT) polymerization to explore the role of neutral hydrophobic units in photosensitizer delivery. The composition of DMAEA units in P(BA-co-DMAEA) was adjusted to 0.46, which is comparable to that of P(St-co-DMAEA)-b-PPEGA. The size distribution of the P(BA-co-DMAEA)-b-PPEGA micelles changed when the pH decreased from 7.4 to 5.0, indicating their pH-responsive ability. The photosensitizers, 5,10,15,20-tetrakis(pentafluorophenyl)chlorin (TFPC), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), protoporphyrin IX (PPIX), and ZnPc were examined as payloads for the P(BA-co-DMAEA)-b-PPEGA micelles. The encapsulation efficiency depended on the nature of the photosensitizer. TFPC-loaded P(BA-co-DMAEA)-b-PPEGA micelles exhibited higher photocytotoxicity than free TFPC in the MNNG-induced mutant of the rat murine RGM-1 gastric epithelial cell line (RGK-1), indicating their superiority for photosensitizer delivery. ZnPc-loaded P(BA-co-DMAEA)-b-PPEGA micelles also exhibited superior photocytotoxicity compared to free ZnPc. However, their photocytotoxicity was lower than that of P(St-co-DMAEA)-b-PPEGA. Therefore, neutral hydrophobic units, as well as pH-responsive units, must be designed for the encapsulation of photosensitizers.

Controllable Synthesis of Heterofunctionalized Polyethers via Intramolecular Phosphonium Bisborane Lewis Pair-Catalyzed Immortal Ring-Opening Polymerization

A metal-free phosphonium bisborane Lewis pair (PBB-Br) was demonstrated to realize the immortal ring-opening polymerization (iROP) of propylene oxide (PO) under mild conditions with alcohols as chain-transfer agents (CTAs). Narrow dispersed poly(propylene oxides) (PPOs) with controllable molecular weights predicted from the [PO]0/([PBB-Br]0 + [CTAs]0) molar ratio were obtained in quantitative conversion. These findings indicated the iROP feature of PBB-Br-catalyzed PO polymerization. The rapid, reversible, and quantitative chain transfer assured the iROP characteristic for an intramolecular Lewis pair catalyst PBB-Br, so various well-defined heterofunctionalized PPOs were easily produced. All the α,ω-difunctionalized PPOs were carefully characterized. Density functional theory (DFT) calculations reveal that the chain transfer to the CTA process is almost barrierless (0.8 kcal mol–1) and thermodynamically favorable as compared to chain propagation. Moreover, PPO-based block copolyethers were easily obtained in one-pot using epoxide mixtures. This research demonstrated that the delicately designed intramolecular synergistic Lewis pair offered a powerful and controllable method to prepare various heterofunctionalized PPO samples with high values.

Facilely Control Grafting Density and Side Chain Composition of Bottlebrush Polymer.

Control over polymer architecture and composition is essential for disclosing structure-property relationships and developing high-performance materials. Herein, a new method is successfully developed to synthesize bottlebrush polymer (BP) with controllable graft density and side chain composition by "grafting-from" strategy using in situ halogen exchange and reversible chain transfer catalyzed polymerization (RTCP). The main chain of the BP is first synthesized by the polymerization of methacrylates containing alkyl bromide as a side group. Then, the alkyl bromine is quantitatively converted to alkyl iodide with sodium iodide (NaI) via in situ halogen exchange to efficiently initiate the RTCP of methacrylates. By adjusting the input amount of NaI and monomers in sequence, BP named PBPEMA-g-PMMA/PBzMA/PPEGMEMA which contains three different kinds of polymer side chains including hydrophilic PPEGMEMA, hydrophobic PMMA, and PBzMA is synthesized with narrow molecular weight distribution (Mw /Mn ≤1.36). The grafting density and the chain length of each polymer side chain are well controlled by the addition of NaI in batches and following RTCP. Moreover, the obtained BP self-assembled into spherical vesicles in aqueous with hydrophilic coronal structure, core region, and the hydrophobic wall between the former two, which enables to wrap hydrophobic pyrene and hydrophilic Rhodamine 6G separately or simultaneously.

Unraveling the dependence of proton transfer on solvent polarity in ion pairs of carbamates and dithiocarbamates with nitrogen‐based counterions

AbstractSmall, but important, differences in the structure–property relationships between ionomers composed of amidinium or imidazolinium groups with alkylcarbamate or alkyldithiocarbamate counterions have been examined experimentally by us previously. To unravel the sources of these differences, DFT calculations are conducted here for ion‐pair complexes (IPs) of these systems and their corresponding uncharged base and acid components (NPs). Calculations include IPs and NPs in which the amidine/amidinium and imidazoline/imidazolinium groups are anchored to a dimethylsiloxane pentamer. A surprising dependence of proton transfer on the dielectric constant (ε) of the medium is found for the systems: Whereas interconversion between the NPs and IPs is strongly dependent on medium dielectric in systems with an alkylcarbamate, none of the initial IP forms with an alkyldithiocarbamate transforms to an NP. Although the calculations do not include individual solvent–solute molecular interactions, they do probe how the components sense their bulk environments. The lack of detectable reversible proton transfer from the amidinium or imidazolinium cations to the dithiocarbamates is consistent with the “principle of proton affinity/pKa equivalence”: Because the acidity of dithiocarbamates is higher than that of carbamates, the gap between their proton affinities (ΔPA) is decreased, favoring stronger electrostatic‐based H‐bonds in the ion‐pair complexes of the dithiocarbamates. The differences can also be estimated from the Deuri–Phukan nucleophilicity index scale, which is based on DFT calculations and suggests a strong dependence of proton transfer on the nucleophilicity of the base and the dielectric constant of the solvent. Predictions from these calculations on some important experimental systems are mentioned.

Multi-signal amplification electrochemiluminescence biosensor based on GO-CDTPA-AuNPs composites and PET-RAFT for ultrasensitive detection of KRAS G12C mutation

The detection of the Kirsten Rat Sarcoma (KRAS) G12C point mutation plays an important role in the early diagnosis and individualized treatment of non-small cell lung cancer (NSCLC). Herein, a novel electrochemiluminescence (ECL) biosensor for the detection of KRAS G12C mutation via GO-CDTPA-AuNPs composites and photo-induced electron/energy transfer reversible addition-fragment chain transfer (PET-RAFT) multi-signal amplification strategy was fabricated for the first time. In this work, gold nanoparticles (AuNPs) were loaded onto the graphene oxide (GO) surface to form a luminol electrochemiluminescence enhanced composite by simple amide reaction and electrostatic adsorption. Specifically, in the presence of KRAS G12C mutation DNA, i.e. target DNA (tDNA), self-assembled hairpin DNA (hDNA) on the biosensor electrode surface was activated after hybridization with the tDNA to expose a 3′-terminal amino group, that could be further linked to GO-CDTPA-AuNPs composites. To increase luminol-based ECL, GO-CDTPA-AuNPs composites contained a lot of photo-induced electron/energy transfer reversible addition-fragment chain transfer (PET-RAFT) agent loaded onto GO surface. PET-RAFT polymerization of N-acryloxysuccinimide (NAS) monomer was initiated to form polymer chains containing multiple binding sites for luminol. Due to the amplification of luminol attachment sites, very high quantities of luminol could be introduced onto the biosensor electrode surface, resulting in significantly amplified ECL signal intensity. Under optimal biosensor fabrication conditions, a good linear relationship between ECL signal intensity and the logarithm of tDNA concentration was observed over the range of 1 fM to 10 nM with a 0.12 fM limit of detection. Moreover, this strategy exhibited high selectivity and excellent applicability for KRAS G12C mutation detection in the clinical human serum samples. Thus, the fabricated biosensor has great potential for application in the clinical diagnosis.

α‐Cyano Triaryl[3]radialene: Unsymmetrical Stereo‐configuration, Clustering‐enhanced Excimer Emission, and Radical‐involved Multimodal Information Switching

Abstract[3]Radialene has a peculiar topology and cross‐conjugation system, representing a unique molecular scaffold in organic materials. Herein, we report a special class of stereoisomeric α‐cyano triaryl[3]radialenes (CTRs) that show concentration‐caused quenching in solution but emit red‐shifted and enhanced luminescence in the crystalline state. Clustering of multiple cyano groups and their through‐space interactions with the [3]radialene ring significantly extend π‐electron communication meanwhile rigidifying the propeller conformation multivalently, thus playing a key role behind the state‐dependent luminescence. These radialenes with a substantial electron affinity undergo a reversible electron transfer transition to anionic radicals with good stability, showing switching of photoabsorption, photoluminescence and electron spin resonance (ESR) signal. We also established proof‐of‐concept applications of CTRs for multimodal information encryption and chemical sensing.

α-Cyano Triaryl[3]radialene: Unsymmetrical Stereo-configuration, Clustering-enhanced Excimer Emission, and Radical-involved Multimodal Information Switching.

[3]Radialene has a peculiar topology and cross-conjugation system, representing a unique molecular scaffold in organic materials. Herein, we report a special class of stereoisomeric α-cyano triaryl[3]radialenes (CTRs) that show concentration-caused quenching in solution but emit red-shifted and enhanced luminescence in the crystalline state. Clustering of multiple cyano groups and their through-space interactions with the [3]radialene ring significantly extend π-electron communication meanwhile rigidifying the propeller conformation multivalently, thus playing a key role behind the state-dependent luminescence. These radialenes with a substantial electron affinity undergo a reversible electron transfer transition to anionic radicals with good stability, showing switching of photoabsorption, photoluminescence and electron spin resonance (ESR) signal. We also established proof-of-concept applications of CTRs for multimodal information encryption and chemical sensing.

Enhancing bioelectrocatalytic oxidation of gaseous chlorobenzene by introducing transmembrane Ru4+/Ru3+-mediated reversible intracellular electron transfer

Microbial electrolysis cell (MEC) is a cost-effective process to eliminate chlorinated volatile organic compounds. Poor mass transfer and sluggish intracellular electron transfer remain obstacles. To overcome these, a Ru-mesoporous TiO2/macroporous carbon (Ru-MeT/MaC) bio-anode was tailored here. The hierarchically meso-macroporous structure separated biofilm formation and chlorobenzene adsorption, improving chlorobenzene mass transfer. Further, modifying Ru created a reversible intracellular electron transfer pathway by introducing transmembrane Ru4+/Ru3+ redox couple within bacteria. Such a unique transmembrane introduction induced a compelling bacteria-electricity synergism accompanied by the acclimation of dual-functional genera (degrader & exoelectrogen), promoting the decomposition of aromatic compounds toward organic acids. Those features enabled the resulting MEC to exhibit a super-prominent chlorobenzene elimination capacity (136.7 g m−3 h−1) with a short empty bed residence time (60 s), superior to those of state-of-the-art bioelectrocatalytic processes reported. Leveraging the reversible electron transfer, the Ru-MeT/MaC bio-anode was operated in the charging-discharging mode to further enhance chlorobenzene removal. SynopsisThe concept of introducing bioavailable conductive redox couple into bacteria via reasonably designing the functional structure of the bio-anode is expected to enhance the bioelectrocatalytic oxidation of hydrophobic Cl-VOCs and therefore alleviate air pollution.

Dicarbonate acrylate based single-ion conducting polymer electrolytes for lithium batteries

A series of carbonate-based single-ion conducting, solid polymer electrolytes were synthesized via reversible addition-fragmentation transfer copolymerization with anionic monomers. The abundant carbonate groups within the copolymers provide electron-delocalized complexation sites to aid Li+ dissociation from the polymer backbone, and the cyclic carbonates also provide a crosslinking site to improve mechanical properties. A single-ion conducting network polymer electrolyte prepared with dicarbonate acrylate (DCA) and trifluoromethane sulfonimide methacrylate (MTFSI) was UV-cured with a polyethylene oxide crosslinker and plasticized with vinylene carbonate (VC) to produce a high conductivity and high-performance electrolyte. The DCA-based polymer electrolyte had 0.16 mS/cm ionic conductivity at room temperature and transference number of 0.92. The use of VC was compared to a conventional electrolyte, ethylene carbonate and diethyl carbonate. The polymer electrolyte with VC showed excellent compatibility and stability with lithium. A lithium metal/lithium iron phosphate full cell with VC showed higher capacity and cycling stability than a cell with conventional plasticizers.

Reversible control of energy transfer efficiency using thermoresponsive volume-phase-transition gel and application to luminescence chromism

For poly-N-isopropylacrylamide (PNIPA) gels with lower critical solution temperatures (LCSTs), a slight temperature shift dramatically changes the water content inside the gel. Unless bonded chemically, hydrophobic molecules—such as polycyclic aromatic hydrocarbons (PAHs)—added to the PNIPA gel aggregate to form a separate phase when the gel is in the swollen state and diffuse into the gel in the dehydrated state. This phenomenon can be leveraged by incorporating PAHs with energy transfer capabilities, such as anthracene (AN) and tetracene (TE), within a PNIPA gel and using the hydration state of the gel to modulate the distance between these molecules. Using this strategy, we were able to promote energy transfer in the aggregated state and suppress it in the dehydrated state of the gel. The emission from the energy-acceptor TE was dominant under accelerated energy transfer conditions, whereas when energy transfer was suppressed, emission from the AN excited species was also observed. The reversible transfer of energy, controlled by water absorption and dehydration, resulted in unprecedented luminescence chromism.