Common Solvents Research Articles

Stable Lanthanide–Organic Frameworks: Crystal Structure, Photoluminescence, and Chemical Sensing of Vanillylmandelic Acid as a Biomarker of Pheochromocytoma

Several isostructural lanthanide metal-organic frameworks, viz. [Ln(DCHB)1.5phen]n (Ln-MOFs, where Ln = Eu for 1, Tb for 2, Sm for 3 and Dy for 4), are successfully synthesized through the hydrothermal reactions of 4'-di(4-carboxylphenoxy)hydroxyl-2, 2'-bipyridyl (H2DCHB) and lanthanide nitrates as well as chelator 1,10-phenantroline (phen). These structures are characterized by single-crystal X-ray diffraction, and the representative Ln-MOF 1 is a fivefold interpenetrated framework with the uncoordinated Lewis base N sites form DCHB2- ligands. The photoluminescence research studies reveal that Ln-MOFs 1-4 exhibit characteristic fluorescent emissions from ligand-induced lanthanide Ln(III) ions, while the single-component emission spectra of Ln-MOF 4 are all located in a white region under different excitations. The absence of coordinated water and the interpenetration property of the structures are conducive to the structure rigidity, and the results display that Ln-MOF 1 has high thermal/chemical stabilities in common solvents and a wide pH range as well as the boiling water. Notably, luminescent sensing studies reveal that Ln-MOF 1 with prominent fluorescence properties can perform in highly sensitive and selective sensing of vanillylmandelic acid (VMA) in aqueous systems (KSV = 562.8 L·mol-1; LOD = 4.6 × 10-4 M), which can potentially establish a detection platform for the diagnosis of pheochromocytoma via multiquenching mechanisms. Moreover, the 1@MMMs sensing membranes comprised of Ln-MOF 1 and a poly(vinylidene fluoride) (PVDF) polymer can also be facilely developed for VMA detection in aqueous media, suggesting the enhanced convenience and efficiency of practical sensing applications.

Hydrophile-lipophile balance solid phase extraction of surface water organics: Fluorescent elution preference and overlooked fractions

Fluorescent dissolved organic matter (FDOM) in surface water has broad implications on water quality research and operations. Solid phase extraction (SPE) is the most widely used technique to extract FDOM. However, fluorescent elution preferences by common solvents and content of quantifiable chromophores in waste fraction remain largely unknown, both quantitatively and qualitatively. In this work, the preferential selection of various types of FDOM captured by and lost from SPE as characterized by the fluorescence excitation-emission matrix (EEM) were investigated. Three elution solvents (methanol, acetone, and dichloromethane) were adopted to elute the DOM that was enriched on a typical SPE sorbent. Results revealed that high polarity (methanol) and medium polarity (acetone) solvents eluted the highest variety and quantity of humic acid-like substances (Region V), while the low polarity (dichloromethane) elution solvent was more suitable for eluting tyrosine (Region I) and tryptophan (Region II). Compared to eluting only with methanol, sequential elution and recombination using the three aforementioned solvents demonstrated a significant increase in not only DOC recovery (by 7%), but fluorescence integral values and fluorescence characteristics covering collectively much larger fluorescence regions that more closely resembled raw water. For the first time, the fluorescence EEM of waste after loading the sample revealed a previously overlooked FDOM loss of 20%, caused by ineffective adsorption onto the solid phase resin. Substantial carbonaceous and nitrogenous FDOM were present in this fraction (the fluorescence intensity of aromatic protein in waste exceeds 20% of that in raw water), indicating possible underestimations of FDOM-related research in areas such as disinfection byproduct and toxicity work. The results of this study provide both a qualitative and quantitative characterization of the elution and lost products of SPE in capturing FDOM.

Study of sensing mechanism of heterocyclic hazardous vapors with Metal Phthalocyanines

Industrial residues release harmful chemicals in the environment accruing toxicity in soil, air and hazard to mankind. Tetrahydrofuran (THF) and pyridine are common solvents utilized by chemical industries and research institutes. Low boiling point of these solvents amends their inhalation probability enhancing hazardous effects. Present study reports the fabrication of low power (1 V) driven chemresistors using organic dyes (Metal phthalocyanines (MPcs)) for the detection of industrial residues THF and pyridine. The variation in electrical signal of MPcs with exposure of reducing gases and tendency of THF and pyridine to donate lone pair's for charge transfer mechanism is utilized as detection principle. Aluminium Phthalocyanine hydroxide (AlPcOH), functionalized Copper and Nickel Phthalocyanines (CuPcS and NiPcS) and their various permuted combinations has been taken for sensing studies. It has been found that MPcs show higher responses towards pyridine (≈1571 times) under non-interfering and (≈169 times) at ambient conditions as compared to THF. For the case of THF, CuPcS-NiPcS composite has been found to exhibit maximum response and for pyridine CuPcS-AlPcOH-NiPcS composite exhibited maximum sensing response. AlPcOH has been found to decrease the recovery times of the composites, which is especially useful during pyridine sensing.

Near‐Intrinsic Photo‐ and Electroluminescence from Single‐Walled Carbon Nanotube Thin Films on BCB‐Passivated Surfaces

AbstractTheir outstanding electrical and optical properties make semiconducting single‐walled carbon nanotubes (SWCNTs) highly suitable for charge transport and emissive layers in near‐infrared optoelectronic devices. However, the luminescence spectra of SWCNT thin films on commonly used glass and Si/SiO2 substrates are often compromised by broadening of the main excitonic emission and unwanted low‐energy sidebands. Surface passivation with a commercially available, low dielectric constant, cross‐linked bis‐benzocyclobutene‐based polymer (BCB) enhances the emission properties of SWCNTs to the same level as hexagonal boron nitride (h‐BN) flakes do. The presence of BCB suppresses sideband emission, especially from the Y1 band, which is attributed to defects introduced by the interaction of the nanotube lattice with oxygen‐containing terminal groups of the substrate surface. The facile and reproducible deposition of homogeneous BCB films over large areas combined with their resistance against common solvents and chemicals employed during photolithography make them compatible with standard semiconductor device fabrication. Utilizing this approach, light‐emitting (6,5) SWCNT network field‐effect transistors are fabricated on BCB‐treated glass substrates with excellent electrical characteristics and near‐intrinsic electroluminescence. Hence, passivation with BCB is proposed as a standard treatment for substrates used for spectroscopic investigations of and optoelectronic devices with SWCNTs and other low‐dimensional emitters.

A three-dimensional terbium metal − organic framework fluorescent sensor for efficient detection of chloroquine phosphate in serum

A novel three-dimensional (3D) anionic anhydrous metal − organic framework (MOF), {[NH2(CH3)2]·[Tb(pdca)2]}n (Tb-MOF; H2pdca = 2,5-pyridinedicarboxylic acid) has been triumphantly fabricated and structurally characterized. The obtained Tb-MOF displays good stability in some common solvent systems and high temperature environments. The luminescence properties of Tb-MOF are investigated by fluorescence spectra, and the results exhibit superb characteristic emission of Tb3+ ions, which lay a foundation for exploring the fluorescence sensing application of the material. More importantly, based on competitive absorption and dynamic quenching, Tb-MOF can be applied to detect chloroquine phosphate (CQ) used for the treatment of COVID-19 and malaria, showing high sensitivity and fast response speed in the sensing process. Notably, the specific quenchingeffect between Tb-MOF and CQ in the serum system without interference from other components, demonstrating the practical application potential of Tb-MOF.

Porous Organic Cages.

Porous organic cages (POCs) are a relatively new class of low-density crystalline materials that have emerged as a versatile platform for investigating molecular recognition, gas storage and separation, and proton conduction, with potential applications in the fields of porous liquids, highly permeable membranes, heterogeneous catalysis, and microreactors. In common with highly extended porous structures, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic polymers (POPs), POCs possess all of the advantages of highly specific surface areas, porosities, open pore channels, and tunable structures. In addition, they have discrete molecular structures and exhibit good to excellent solubilities in common solvents, enabling their solution dispersibility and processability─properties that are not readily available in the case of the well-established, insoluble, extended porous frameworks. Here, we present a critical review summarizing in detail recent progress and breakthroughs─especially during the past five years─of all the POCs while taking a close look at their strategic design, precise synthesis, including both irreversible bond-forming chemistry and dynamic covalent chemistry, advanced characterization, and diverse applications. We highlight representative POC examples in an attempt to gain some understanding of their structure-function relationships. We also discuss future challenges and opportunities in the design, synthesis, characterization, and application of POCs. We anticipate that this review will be useful to researchers working in this field when it comes to designing and developing new POCs with desired functions.

COSMO prediction of siloxane compounds absorption on type 3 and type 5 deep eutectic solvents

This study reports a Conductor-like Screening MOdel for Real Solvents (COSMO-RS) prediction for 151 type 3 (polar) and type 5 Deep Eutectic Solvents (DES, non-polar) for absorption of hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane. Through the examination of generated sigma surfaces, sigma profiles, and sigma potentials, it was found that while the siloxane chains offer sufficiently strong hydrogen bond accepting sites, the steric hindrance of the methyl groups cause less polar solvents (type 5) to outperform the more polar ones (type 3). The thermodynamic study predicts thymol-based type 5 DES as significantly more affinitive for siloxane compounds than common conventional solvents (DEA, MEA, MDEA, menthol, and DPEG Blend) with lnγ activity coefficients reaching low as −0.64. Enthalpy of mixing study shows Vander Waals interactions dominate DES-siloxane compound interactions over hydrogen bonding by over 10x enthalpic release, clarifying discrepancy in literature on how siloxanes are solvated by DES. Thymol: Stearic acid (4:1) showed the lowest excess enthalpy of mixing at −10.4 kcal/mol. An environmental health and safety (EHS) study show the best performing DES components (camphor, capric acid, lauric acid, myristic acid, stearic acid, undecenoic acid, borneol, betaine, hexadecanoic acid, and thymol) are potentially environmentally benign and safe for operation procedures.

One-flow multi-step synthesis of a monomer as a precursor of thermal-conductive semiconductor packaging polymer via multi-phasic separation

As semiconductor technology becomes rapidly advanced, semiconductor packaging materials demand critical characteristics in various aspects. Besides, the development of these new epoxy mold compounds (EMC) by batch reaction process requires time-consuming experimentation and the multi-step chemistry further reduces the efficiency of the synthetic process. We report a one-flow multi-step process for the synthesis of newly developed Np-C4-Np, which comprises two mesogenic units connected with a flexible spacer, as a monomeric precursor of semiconductor packaging material. Graphical convolution neural network (GCNN), a deep learning model, predicts a common solvent for three-step reactions, thereby enabling serial esterification-deprotection-epoxidation integrated with in-situ multi-phasic separations that were accomplished within 76 min in flow over the long batch process (>20 h excluding separation step). Eventually, the Np-C4-Np is synthesized rapidly with higher space–time yield compared to the batch system, thus confirming benefits in terms of productivity. Moreover, we prevent the deterioration of electronic circuits during the semiconductor packaging process by lowering the molding temperature (126 °C) of EMC and quickly dissipating the heat generated from semiconductor chip by increasing the thermal conductivity (0.34 W ∙ m−1∙ K−1) of EMC.

A facile, time-saving fabrication method of high purity CsPbBr3 films for efficient solar cells

All-brominated cesium lead bromide (CsPbBr3) perovskite solar cells (PSCs) have drawn growing attention owing to unprecedented stability in the family of perovskites. It usually employs a two-step method to prepare CsPbBr3 films owing to the low solubility of CsBr in the common solvents. The researchers have to provide enough Cs source through increasing the reaction time or repeat times of CsBr deposition so as to obtain the target CsPbBr3 films. The long preparation period and tedious process increase the time and economic cost, which may limit the practical application of CsPbBr3 solar cells. Herein, a facile method is proposed to prepare CsPbBr3 films, in which appropriate CsBr is pre-introduced into PbBr2 solutions in the first step, and CsBr/2-methoxyethanol solution (∼35 mg mL−1) is used as solution conversion medium in the second step. Benefitting from the pre-introduction of CsBr in the first step, a single phase of CsPbBr3 films with full coverage can be conversed for only once CsBr supplementation. After integrating the CsPbBr3 films into a solar cell, it delivers a power conversion efficiency (PCE) of 7.48% basing on the configuration of FTO/TiO2/CsPbBr3/Carbon. This work largely shortens the preparation time of CsPbBr3 films, which may provide a practical way for the large-scale production of CsPbBr3 based devices.

Regulating the reduction reaction pathways via manipulating the solvation shell and donor number of the solvent in Li-CO2 chemistry

Transforming CO2 into valuable chemicals is an inevitable trend in our current society. Among the viable end-uses of CO2, fixing CO2 as carbon or carbonates via Li-CO2 chemistry could be an efficient approach, and promising achievements have been obtained in catalyst design in the past. Even so, the critical role of anions/solvents in the formation of a robust solid electrolyte interphase (SEI) layer on cathodes and the solvation structure have never been investigated. Herein, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in two common solvents with various donor numbers (DN) have been introduced as ideal examples. The results indicate that the cells in dimethyl sulfoxide (DMSO)-based electrolytes with high DN possess a low proportion of solvent-separated ion pairs and contact ion pairs in electrolyte configuration, which are responsible for fast ion diffusion, high ionic conductivity, and small polarization. The 3 M DMSO cell delivered the lowest polarization of 1.3 V compared to all the tetraethylene glycol dimethyl ether (TEGDME)-based cells (about 1.7 V). In addition, the coordination of the O in the TFSI- anion to the central solvated Li+ ion was located at around 2 Å in the concentrated DMSO-based electrolytes, indicating that TFSI- anions could access the primary solvation sheath to form an LiF-rich SEI layer. This deeper understanding of the electrolyte solvent property for SEI formation and buried interface side reactions provides beneficial clues for future Li-CO2 battery development and electrolyte design.

Focussed Helium Ion Beam Exposure of Polymethylmethacrylate: Positive or Negative Tone Images, Polyenes, and Fluorescent Carbon Layers

Understanding chemical transformations in polymethylmethacrylate (PMMA) during helium ion beam exposure will help researchers involved in nanofabrication, materials synthesis or transformation, patterning polyenes, developing phantoms for radiation therapy, and realizing carbonaceous quantum emitters. The level of conjugation in PMMA can be controlled using a helium ion beam to realize patterns that are suitable for positive tone lithography, polyenes, dye‐like fluorescent materials, and polycyclic aromatic compounds with very similar properties to carbon dots. High‐resolution dose studies employing Raman scattering and atomic force microscopy (AFM) reveal the conditions under which these very different conjugated carbonaceous materials form, their spatial distribution, and dissolution characteristics in common solvents.

Silver(I) Coordination Polymer Ligated by Bipyrazole Me4bpzH2, [Ag(X)(Me4bpzH2)] (X = CF3CO2− and CF3SO3−, Me4bpzH2 = 3,3′,5,5′-Tetramethyl-4,4′-bipyrazole): Anion Dependent Structures and Photoluminescence Properties

Coordination polymers of transition metal ions are fascinating and important to coordination chemistry. One of the ligands known to form particularly interesting coordination polymers is 3,3',5,5'-tetramethyl-4,4'-bipyrazole (Me4bpzH2). Group 11 metal(I) ion coordination polymers, other than those of copper(I), are relatively easy to handle because of their low reactivity towards dioxygen and moisture. However, the known silver(I) coordination polymers often have poor solubility in common solvents and so cannot be easily analyzed in solution. By using a tetramethyl substituted bipyrazole ligand, we have synthesized more soluble silver(I) complexes that contain the trifluoromethyl group in the coordinated ions CF3CO2- and CF3SO3- in [Ag(CF3CO2)(Me4bpzH2)] and [Ag(CF3SO3)(Me4bpzH2)]. We determined both structures by single-crystal X-ray analysis at low temperatures and compared them in detail. Moreover, we investigated the solution behavior of these coordination polymers by 1H-NMR, IR, Raman, UV-Vis spectroscopies, and their low-temperature, solid-state photoluminescence. The high-energy band at ~330 nm corresponded to ligand-centered (bipyrazole) fluorescence, and the low-energy band at ~400 nm to ligand-centered phosphorescence resulting from the heavy atom effect.

A Review on the Separation of Volatile Organic Compounds from Wastewater by Pervaporation Processes

The pervaporation process (PV) is one of the membrane separation methods. This process is characterized by low cost, ease of installation, no chemicals added, and work at medium temperatures. The pervaporation process is part of a chain of water treatment processes and has high efficiency in removing pollutants, drying processes, and others. The present review paper would be reviewed the related articles to show the efficiency of the separation of the solution by the pervaporation process by focusing on research that deals with the separation of volatile organic compounds (VOCs) from water such as benzene and toluene. Benzene compound was used to prepare some of the chemicals such as styrene, phenol, cyclohexane, aniline, and polyester resins. Also, it is used in the production of drugs, dyes, insecticides, and plastics, moreover, it is produced from the refineries' operations and mixes with the water used in these operations, where its concentration reaches up to 16 ppm. While toluene is a common solvent used for paints, glues, and printing ink. Toluene compound is produced from the refineries operations and mixes with the water used in these operations, where its concentration reaches up to 55 ppm, where these percentages for benzene and toluene are considered high and very dangerous to humans and the environment which causes many carcinogenic diseases. Also, researchers would be reviewing that worked on developing various types of membranes by adding different materials to improve membrane performance and increase the desired flux of components and separation factors with different working conditions.

Using Prenucleation Aggregation of Caffeine-Benzoic Acid as a Rapid Indication of Co-crystallization from Solutions.

Co-crystal design is a convenient way to remedy the poor biopharmaceutical properties of drugs. Most studies focus on experimental co-crystal screening or computational prediction, but hardly any work has been done toward fast, efficient, and reliable prediction of solution crystallization for co-crystal formation. Here, we study the caffeine-benzoic acid co-crystal system, due to its reported difficulty to crystallize from the solution phase. With this work, we investigate whether there is a link between prenucleation aggregation in solution and co-crystal formation and how to harness this for crystallization prediction. 1H and 13C NMR spectroscopy is used to study the prenucleation interaction between caffeine and benzoic acid in methanol, acetone, and acetonitrile as examples of common solvents. In this system, crystallization from methanol leads to no co-crystallization, from acetone to concomitant crystallization of co-crystal and caffeine, and from acetonitrile to pure co-crystal formation from solution. Strong heteromeric dimers were found to exist in all three solvents. Ternary phase diagrams were defined and a solution-accessible co-crystal region was found for all solvents. For this system, the prenucleation clusters found in solution could be linked to the crystallization of the co-crystal. Crystallization from DMSO did not yield the co-crystal and there were no detectable prenucleation aggregates. NMR spectroscopy to probe dimers in solution can thus be used as a fast, reliable, and promising tool to predict co-crystallization from specific solvents and to screen for suitable solvents for manufacturing and scale-up.

Fabrication of stable solid fluorescent starch materials based on Hantzsch reaction

In this paper, a series of fluorescent starches were prepared simply and effectively by Hantzsch multi-component reaction (MRC). These materials showed bright fluorescence emission. Notably, due to the existence of polysaccharide skeleton, starch molecules can effectively inhibit the common aggregation induced quenching effect caused by the aggregation of conjugated molecules in traditional organic fluorescent materials. Meanwhile, the stability of this material is so excellent that the fluorescence emission of the dried starch derivatives would not destroy after boiling at a high temperature in some common solvents, and even brighter fluorescence can be stimulated in alkaline solution. In addition to fluorescence, starch was also endowed with hydrophobic property by one-pot method connecting long alkyl chains. Compared with native starch, the contact angle of fluorescent hydrophobic starch increased from 29° to 134°. Furthermore, the fluorescent starch can be prepared into film, gel and coating by different processing methods. The preparation of these Hantzsch fluorescent starch materials provide a new way for the functional modification of starch materials and has great application potential in detecting, anti-counterfeiting, security printing and other related fields.

Cover Feature: PdCl(NO) – an iconic compound with corrugated Pd4Cl4 octagons built up by Pd2Cl2(NO)2 moieties (Z. Anorg. Allg. Chem. 6‐7/2023)

The cover picture presents a structural motif of a distorted Pd2Cl2 square in solid PdCl(NO). This iconic compound was firstly synthesized during outstanding research in the late 1950s in Munich, which led to the development of the Wacker process for the conversion of ethene into acetaldehyde by catalysis with PdCl2. More than sixty years after its synthesis, crystals of PdCl(NO) were prepared for the first time and the structure determined by X-ray diffraction. In the monoclinic structure distorted Pd4Cl4 octagons in chair arrangement are interconnected to corrugated layers, forming a two-dimensional polymer insoluble in common solvents. In this compound each Pd atom is connected to a N-O group, bonded alternatively up and down with a Pd-N-O angle of 129°. The bonding situation in PdCl(NO) was investigated by vibrational, electronic and X-ray absorption (XAS) spectroscopies. The XAS measurement at the KIT synchrotron facility uncovers that the charge located at the Pd atom in PdCl(NO) is comparable to that in PdCl2 or PdO (DOI: 10.1002/zaac.202200337).

Synergistic Kinetic Hydrate Inhibition of Pectin, PVP, and PVCap with Monoethylene Glycol

Before injecting any kinetic hydrate inhibitor (KHI) into a flow line, the standard procedure is to dissolve the chemical, which is mostly a polymer, in a solvent such as water, methanol, or glycol. It is ideal if the solvent synergizes with the KHI in hydrate inhibition. In this paper, the synergy of three KHIs, poly(vinylpyrrolidone) (PVP), poly(vinyl caprolactam) (PVCap), and a natural biodegradable polymer Pectin at 0.25 wt %, is investigated with one of the common solvents monoethylene glycol at concentrations (0.5–20 wt %). The hydrate-inhibiting performance of the KHIs and their solvent blends is evaluated using an autoclave to measure the induction time (IT) and the molar hydrate growth rate, which is approximately taken equal to the molar gas consumption rate (HGR/GCR) in constant cooling rate tests and isothermal tests. The individual hydrate inhibition testing results showed that MEG alone at high dosages (up to 20 wt %) is a very poor KHI, while Pectin is a moderate KHI with performance lower than the commercial KHIs (PVP and PVCap) at similar concentrations. The hydrate growth rate of Pectin is however, lower compared to that of both PVP and PVCap. The blends of the KHIs with MEG, showed significant hydrate inhibition synergy in all of the KHI–MEG blends with increasing MEG concentration from 0.5 to 20 wt %. The synergy was maximum at 5 wt % of MEG for all the KHIs with IT enhancement of around 50% for PVP and PVCap and 200% for Pectin. Almost 30–60% reduction in HGR was observed in the blends compared to that of their individual KHI polymer HGRs. Isothermal experiments at 1.5, 6, and 8 °C were done using KHI–MEG blends to simulate possible field/subsea conditions. Among the three KHIs at 0.25 wt % blended with 5 wt % of MEG at 6 °C, PVP–MEG and Pectin–MEG blends gave an almost equal IT of 3.5 h, while the PVCap–MEG blend gave a slightly higher IT of 4.55 h. The HGR of the Pectin–MEG blend was however, the lowest (0.055 m/h) when compared to the PVP–MEG blend HGR (0.08 m/h) and the PVCap–MEG blend HGR (0.075 m/h). Similar IT but lower HGR values were found at 1.5 °C when 20 wt % of MEG with 0.25 wt % of Pectin was used. No hydrates were formed up to 6 days with 0.25 wt % of Pectin and 5 wt % of MEG at 8 °C due to a low subcooling of 1.3 °C. In summary, adding MEG to commercial KHIs such as PVP, PVCap and natural KHI Pectin increases their IT tremendously due to synergy and at the same time lowers their HGRs. As the blends of Pectin–MEG are highly biodegradable, they can be used at locations that have relatively low subcooling requirements and where biodegradability and lower hydrate growth rate are essential as they have similar ITs as that of PVP–MEG blends while lower HGRs than both PVP–MEG and PVCap–MEG blends.

Reversible Growth of Halide Perovskites via Lead Oxide Hydroxide Nitrates Anchored Zeolitic Imidazolate Frameworks for Information Encryption and Decryption.

The low formation energies of metal halide perovskites endow them with potential luminescent materials for applications in information encryption and decryption. However, reversible encryption and decryption are greatly hindered by the difficulty in robustly integrating perovskite ingredients into carrier materials. Here, we report an effective strategy to realize information encryption and decryption by reversible synthesis of halide perovskites, on the lead oxide hydroxide nitrates (Pb13O8(OH)6(NO3)4) anchored zeolitic imidazolate framework composites. Benefiting from the superior stability of ZIF-8 in combination with the strong bond between Pb and N evidenced by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy, the as-prepared Pb13O8(OH)6(NO3)4-ZIF-8 nanocomposites (Pb-ZIF-8) can withstand common polar solvent attack. Taking advantage of blade-coating and laser etching, the Pb-ZIF-8 confidential films can be readily encrypted and subsequently decrypted through reaction with halide ammonium salt. Consequently, multiple cycles of encryption and decryption are realized by quenching and recovery of the luminescent MAPbBr3-ZIF-8 films with polar solvents vapor and MABr reaction, respectively. These results provide a viable approach to integrate the state-of-the-art materials perovskites and ZIF for applications in information encryption and decryption films with large scale (up to 6 × 6 cm2), flexibility, and high resolution (approximate 5 μm line width).

Enhancing Third-Order Nonlinear Optical Property by Regulating Interaction between Zr4(embonate)6 Cage and N, N-Chelated Transition-Metal Cation

Herein, the combination of anionic Zr4L6 (L = embonate) cages and N, N-chelated transition-metal cations leads to a series of new cage-based architectures, including ion pair structures (PTC-355 and PTC-356), dimer (PTC-357), and 3D frameworks (PTC-358 and PTC-359). Structural analyses show that PTC-358 exhibits a 2-fold interpenetrating framework with a 3,4-connected topology, and PTC-359 shows a 2-fold interpenetrating framework with a 4-connected dia network. Both PTC-358 and PTC-359 can be stable in air and other common solvents at room temperature. The investigations of third-order nonlinear optical (NLO) properties indicate that these materials show different degrees of optical limiting effects. It is surprising that increasing coordination interactions between anion and cation moieties can effectively enhance their third-order NLO properties, which can be attributed to the formation of coordination bonds that facilitate charge transfer. In addition, the phase purity, UV-vis spectra, and photocurrent properties of these materials were also studied. This work provides new ideas for the construction of third-order NLO materials.

Reaction monitoring of rose bengal photodegradation in alcohols using multivariate frequency-domain dynamic fluorescence

• Photodegradation of rose bengal (RB) exposed to simulated solar radiation evaluated. • Reaction progress monitored using matrix-formatted frequency domain fluorescence. • RB and photoproduct(s) spectra and kinetics resolved by multivariate data mining. • Facile RB dehalogenation in methanol; no photoproducts observed in cyclohexanol. • Multivariate approach insulates results from distortion by unknown concomitants. The photodegradation of rose bengal (RB) by simulated solar radiation in several air saturated alcohols, monitored using wavelength-resolved frequency-domain dynamic fluorescence measurements, is described. This work illustrates a novel strategy for characterizing photochemical reactions of fluorophores using a combination of reaction monitoring by multichannel frequency domain fluorescence measurements and data mining. Kinetic and mechanistic details of RB photodegradation in the selected alcohols are obtained by resolving the spectra and frequency domain decays of unreacted RB and its fluorescent photoproducts from the multivariate measurements. The analysis indicates that RB exhibits photochemical activities and photodegradation rates that are strongly dependent on solvent properties. An associated benefit of the data mining is the insulation of rate calculations from distortions produced by spectral overlap of undiscovered concomitants. This was most evident in RB photodegradation rates in methanol, which paradoxically, is a common solvent choice for photosensitizer efficiency measurements using RB as the standard reference. RB photodegradation in methanol was not only the fastest of all the solvents investigated at 10.0±1 μM/min, methanol supported the formation of three fluorescent photoproducts that had emission properties consistent with RB dehalogenation. In the remaining alcohols, the rates of RB degradation decreased with decreasing solvent relative polarity and increasing solvent viscosity and only one dehalogenated RB derivative was observed. In octanol, the photodegradation rate was faster than expected based on its dielectric constant at 0.249±0.006 μM/min. In cyclohexanol, no photoproduct formation was detected. These results suggest a role for diffusion control in photoinitiated RB dehalogenation.