DFT Study on the Mechanisms and Selectivities in Rh (III)-Catalyzed [5 + 1] Annulation of 2-Alkenylanilides and 2-Alkylphenols with Allenyl Acetates.

The mechanisms and regio-, chemo-, and stereoselectivity were theoretically investigated in the Rh(III)-catalyzed [5 + 1] annulation of 2-alkenylanilides and 2-alkylphenols with allenyl acetates. Two different reactants, 2-alkenylanilides and 2-alkylphenols, were selected as model systems in the density functional theory calculations. The obtained theoretical results show that both these reactants exhibit similar steps, namely, (1) N-H/O-H deprotonation and C-H activation, (2) allenyl acetate migratory insertion, (3) ß-oxygen elimination, (4) intramolecular nucleophilic addition of the nitrogen/oxygen-rhodium bond resulting in [5 + 1]-annulation, and (5) protonation with the formation of the desired product and regeneration of the Rh(III) catalyst. The theoretical evidence suggests that the selectivity is determined at the step of allenyl acetate's migratory insertion. Moreover, the regioselectivity is driven by electronic effects, while the interaction energies (C-H···π and C-H···O interactions) play a more imperative role in controlling the stereoselectivity. The obtained theoretical results not only well rationalize the experimental observations but also provide important mechanistic insights for related types of [5 + 1]-annulation reactions.

Theoretical Analysis of a Three-Component Reaction between Two Diazo Compounds and a Hydroxylamine Derivative: Mechanism, Enantioselectivity, and Effect of Cooperative Catalysis.

The mechanism, enantioselectivity, and effect of chiral phosphoric acid (CPA) cocatalyst were investigated by the density functional theory (DFT) for the three-component asymmetric aminohydroxylation between two diazo compounds and a hydroxylamine derivative. This type of cascade process is cooperatively catalyzed by Rh2(OAc)4 and CPA. The obtained results clearly indicate that the first step of the global reaction involves a nucleophilic attack at the nitrogen center of N-hydroxyaniline by rhodium-carbene intermediates producing imines. Subsequently, an enolate intermediate was recognized as the key species generated from the second diazo compound and the leaving benzyl alcohol (BnOH) fragment of the first step and in the presence of the same dirhodium catalyst. Then, the reaction is terminated by the asymmetric Mannich-type addition, delivering the aminohydroxylation products of an S-R conformation with the assistance of chiral phosphoric acid. The distortion/interaction analysis shows that the relative distortions of CPA and the enol play a vital role in the energy ordering of the stereocontrolling transition states (TSs). Furthermore, the influence of different substituents in CPA was fully rationalized by distortion/interaction analysis. This study opens up novel synthetic possibilities and improves the reaction predictability when exploring the related types of cooperatively catalyzed organic transformations.

Fabrication of Cellulose Filters Incorporating Metal-Organic Frameworks for Efficient Nicotine Adsorption from Cigarette Smoke.

To prevent negative effects of smoking, there is constant research on the development of various types of sustainable filter materials, capable of removing toxic compounds present in cigarette smoke. Because of the extraordinary porosity and adsorption properties, metal-organic frameworks (MOFs) represent promising adsorbents for volatile toxic molecules such as nicotine. This study reports new hybrid materials wherein six types of common MOFs of different porosity and particle size are incorporated into sustainable cellulose fiber from bamboo pulp, resulting in a series of cellulose filter samples abbreviated as MOF@CF. The obtained hybrid cellulose filters were fully characterized and investigated in nicotine adsorption from cigarette smoke, using a specially designed experimental setup. The results revealed that the UiO-66@CF material features the best mechanical performance, facile recyclability, and excellent nicotine adsorption efficiency that attains 90% with relative standard deviations lower than 8.80%. This phenomenon may be caused by the large pore size, open metal sites, and high loading of UiO-66 in cellulose filters. Additionally, the high adsorption capacity showed almost 85% removal of nicotine after the third adsorption cycle. The DFT calculation methods allowed further investigation of the nicotine adsorption mechanism, showing that the energy difference between HOMO and LUMO for UiO-66 was the closest to that of nicotine, which further proves the adsorption ability of nicotine by this material. Owing to the flexibility, recyclability, and excellent adsorption performance, the prepared hybrid MOF@CF materials may find prospective applications in nicotine adsorption from cigarette smoke.

Ratiometric Luminescent Thermometer Based on the Lanthanide Metal-Organic Frameworks by Thermal Curing.

The high-performance optical thermometer probes are of great significance in diverse areas; lanthanide metal-organic frameworks (Ln-MOFs) are a promising candidate for luminescence temperature sensing owing to their unique luminescence properties. However, Ln-MOFs have poor maneuverability and stability in complex environments due to the crystallization properties, which then hinder their application scope. In this work, the Tb-MOFs@TGIC composite was successfully prepared using simple covalent crosslinking through uncoordinated -NH2 or COOH on Tb-MOFs reacting with the epoxy groups on TGIC {Tb-MOFs = [Tb2(atpt)3(phen)2(H2O)]n; H2atpt = 2-aminoterephthalic acid; phen = 1,10-phenanthroline monohydrate}. After curing, the fluorescence properties, quantum yield, lifetime, and thermal stability of Tb-MOFs@TGIC were remarkably enhanced. Meanwhile, the obtained Tb-MOFs@TGIC composites exhibit excellent temperature sensing properties in the low-temperature (Sr = 6.17% K-1 at 237 K), physiological temperature (Sr = 4.86% K-1 at 323 K), or high-temperature range (Sr = 3.88% K-1 at 393 K) with high sensitivity. In the temperature sensing process, the sensing mode of single emission changed into double emission for ratiometric thermometry owing to the back energy transfer (BenT) from Tb-MOFs to TGIC linkers, and the BenT process enhanced with the increase of temperature, which further improved the accuracy and sensitivity of temperature sensing. Most notably, the temperature-sensing Tb-MOFs@TGIC can be easily coated on the surface of polyimide (PI), glass plate, silicon pellet (SI), and poly(tetrafluoroethylene) plate (PTFE) substrates by a simple spraying method, which also exhibited an excellent sensing property, making it applicable for a wider T range measurement. This is the first example of a postsynthetic Ln-MOF hybrid thermometer operative over a wide temperature range including the physiological and high temperature based on back energy transfer.

Hybrid composites of lanthanide metal-organic frameworks with epoxy silanes for highly sensitive thermometry.

Post-synthetic modification of metal-organic frameworks (MOFs) and fabrication of hybrid composites are currently hot topics in the development of new functional materials. In this study, a facile and direct approach for coupling of lanthanide MOFs with epoxy silanes was developed, providing an access to a new series of functional composites. Two types of commercially available epoxy silane, namely 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS) and (3-glycidoxypropyl)methyl diethoxysilane (KH563), were used to modify Ln-BTB MOFs ([Ln(BTB)(H2O)]n·2n(C6H12O); Ln = Tb or Eu0.001Tb0.999; H3BTB = 1,3,5-benzenetrisbenzoic acid) via covalent grafting involving mechanical grinding, epoxide coupling and curing reactions. The fabricated composites (Tb-BTB@ECTMS, Eu0.001Tb0.999-BTB@ECTMS, Tb-BTB@KH563, Eu0.001Tb0.999-BTB@KH563) and their Ln-MOF precursors were fully characterized, including a detailed study of their stability and fluorescence properties. The obtained composites show high thermal and solution stability, under boiling water conditions and in a wide pH range of 1-12. Application of the composites as temperature sensors in the 197-297 K and 273-343 K temperature ranges was explored in detail, revealing a remarkable sensing behavior. For example, Tb-BTB@ECTMS shows a maximum relative sensitivity (Sr) of 6.85% K-1 at 343 K. Eu0.001Tb0.999-BTB@ECTMS represents a white-light emission material with the CIE coordinates (0.3194, 0.3049) that are very close to those of white light, along with good temperature sensing performance and a relative sensitivity of 4.32% K-1 at 297 K. An enhanced performance of the composites in comparison with the parent MOF materials as well as the mechanism of energy transfer were rationalized by DFT calculations. By unveiling a facile and efficient method for improving the stability of luminescent MOFs, via post-synthetic grafting with epoxy silanes, the present study will stimulate further research at the interface of materials chemistry, MOF design, photoluminescence and temperature sensing.

DFT Rationalization of Gold(I)-Catalyzed Couplings between Alkynyl Thioether and Nitrenoid Derivatives: Mechanism, Selectivity Patterns, and Effects of Substituents.

The present work focuses on a theoretical investigation of mechanistic features, chemoselectivity, regioselectivity, and effect of substituents in the gold-catalyzed reactions of alkynyl thioethers and isoxazoles. The DFT calculations reveal that the nucleophilic attack of isoxazole to a ß-position of catalyst-bound ynamide forms a vinyl intermediate. This undergoes cleavage of the N-O isoxazole bond and isomerizes to form an α-imino α'-sulfenyl gold carbene complex with stabilization of the Au-S interaction. For 3,5-dimethylisoxazole, the reaction follows a formal [3 + 2] cycloaddition pathway and a 1,3-H migration to give the pyrrole products. Replacement of 3,5-dimethylisoxazole by 3,5-dimethyl-4-phenylisoxazole leads to the formation of deacylative annulation products and desulfenylated 3-acylated pyrroles. Reactions with 4-methyl-3,5-diphenylisoxazoles induce the formation of N-acylated pyrroles and desulfenylated 3-acylated pyrroles. For the minor pathway, the α-addition and 1,2-S migration result in sulfur-substituted ß-keto enamide derivatives. In addition, the unique features of regio- and chemoselectivity were rationalized by the distortion and interaction analysis. Apart from fully rationalizing the experimental results, the theoretical DFT data give an important support for comprehending related types of reaction mechanisms.

Safety, Tolerability and Pharmacokinetics of the Serotonin 5-HT6 Receptor Antagonist, HEC30654, in Healthy Chinese Subjects.

Background and Objective: HEC30654 is a selective 5-HT6 receptor antagonist that was safe and well-tolerated in preclinical models of Alzheimer's disease. The objective of this double-blind, randomized, placebo-controlled clinical trial was to evaluate the safety, tolerability, and pharmacokinetic profile of HEC30654 after single ascending doses in healthy Chinese subjects. Methods: Healthy volunteers received a single oral dose of HEC30654 (5, 10, 15, 30, 60 mg). Safety and tolerability assessments included adverse events, vital signs, and findings on electrocardiograms, electroencephalograms, physical examination, and clinical laboratory tests. Pharmacokinetic analysis of HEC30654 and its major metabolite HEC93263 were conducted in blood, urine, and fecal samples. Results: Single doses of HEC30654 up to 30 mg were generally safe and well tolerated, but dose escalation was terminated early as the 60 mg HEC30654 treatment group met the pre-defined stopping rules specified in the protocol. Median tmax of HEC30654 was 6 h (range, 4-12 h), t1/2 of 10-60 mg HEC30654 ranged from 52.1 to 63.8 h. Exposure to HEC30654 across the dose range explored in this study increased more than in proportion to dose. Metabolism of HEC30654 to HEC93263 was slow (<10%), and HEC30654 was mainly eliminated unchanged through feces. Conclusion: Single doses of HEC30654 up to 30 mg were generally safe and well tolerated. Based on preclinical efficacy in various models of cognition, HEC30654 may represent a therapeutic option for symptomatic treatment of cognitive disorders.

Epoxy Functional Composites Based on Lanthanide Metal-Organic Frameworks for Luminescent Polymer Materials.

The integration of metal-organic frameworks (MOF) into organic polymers represents a direct and effective strategy for developing innovative composite materials that combine the exceptional properties of MOFs with the robustness of organic polymers. However, the preparation of MOF@polymer hybrid composites requires an efficient dispersion and interaction of MOF particles with polymer matrices, which remains a significant challenge. In this work, a new simple and direct approach was applied for the development of Ln-MOF@polymer materials. A series of Ln-MOF@TGIC composites {Ln-MOF = [Ln(µ3-BTC)(H2O)6]n (Ln-BTC), where Ln = Eu, Tb, Eu0.05Tb0.95; H3BTC = 1,3,5-benzenetricarboxylic acid; TGIC = triglycidyl isocyanurate} were successfully obtained by applying a grinding method via the chemical bonding between uncoordinated carboxylate groups in Ln-BTC and epoxy groups in TGIC. The Ln-BTC@TGIC materials possess significant fluorescence characteristics with superior emission lifetimes and quantum yields if compared to parent Ln-MOFs. Interestingly, under the UV irradiation, a considerable color change from yellow in Eu0.05Tb0.95-BTC to red in Eu0.05Tb0.95-BTC@TGIC was observed. The energy-transfer mechanism was also rationalized by the density functional theory (DFT) calculations. The developed Ln-BTC@TGIC composites were further applied as functional fluorescent coatings for the fabrication, via a simple spraying method, of the flexible polyimide (PI) films, Ln-BTC@TGIC@PI. Thus, the present work unveils a new methodology and expands its applicability for the design and assembly of stable, multicomponent, and soft polymer materials with remarkable fluorescence properties.

DFT Quest of the Active Species of the Gallium-Mediated Coupling of Methylidenemalonates and Acetylenes.

In this study, three different Ga-containing systems based on GaCl3, Ga2Cl6, or ionic [Ga(L)3][GaCl4]3 (L = methylidenemalonate) complex were screened to elucidate the mechanism, regioselectivity, chemoselectivity, and role of Ga mediator in the reaction between two types of acetylenes (phenylacetylene and but-1-yn-1-ylbenzene) and methylidenemalonates, i.e., the 1,2-zwitterionic precursors that are similar to intermediates derived from donor-acceptor cyclopropanes (DACs). Our DFT calculation results clearly show that the ionic gallium complex [Ga(L)3][GaCl4]3 represents the key mediator in the title reaction. After the formation of such a complex, the first reaction step is the nucleophilic addition of phenylacetylene or but-1-yn-1-ylbenzene to [Ga(L)3][GaCl4]3, generating an unstable vinyl cation intermediate. In the phenylacetylene system, this vinyl cation intermediate accepts a chlorine atom from [GaCl4]- to give E-configuration intermediate. Then, the above process occurs to other two ligands of the Ga(III) complex to furnish a final product. On the other hand, in the but-1-yn-1-ylbenzene system, the vinyl cation intermediate prefers to undergo Friedel-Crafts (F-C) alkylation to generate a five-membered ring intermediate. This process is repeated on the other two methylidenemalonate ligands, giving rise to a final cyclization product. The distortion/interaction analysis shows that in the nucleophilic addition step the distortion energy of the Ga complex part is the main factor that influences the activation energy. Furthermore, the global reactivity index (GRI) analysis indicates that the Ga-complex model has the highest electrophilicity index ω, thus leading to the lowest energy barrier among three Ga-based models. In addition, DFT results reveal that the regioselectivity (E-configuration preference) and chemoselectivity (chloration or F-C alkylation) are mainly controlled by the steric effect rather than the electronic effect. The main findings of the present work provide a new way to analyze and rationalize various Ga-mediated reactions, which might also be extrapolated to organic transformations undergoing in the presence of aluminum and indium complexes.

DFT Study on Zr-Catalyzed Alkene Hydroaminoalkylation: Origin of Regioselectivity, Diastereoselectivity, and Influence of Substrate.

A DFT study was carried out to investigate a zirconium-catalyzed hydroaminoalkylation of alkenes with N-silylated benzylamine. A global reactivity index (GRI) analysis showed that that substrates act as electrophiles while the active zirconaaziridine behaves as a nucleophile. Furthermore, the distortion/interaction analysis unveiled the role of the distortion and interaction energies in controlling the regioselectivity and diastereoselectivity when different alkene substrates are used. These results provide an in-depth analysis on how the substrate type influences the product selectivity.

Risk Factor Analysis and Risk Prediction Model Construction of Pressure Injury in Critically Ill Patients with Cancer: A Retrospective Cohort Study in China.

BACKGROUND The aim of this study was to analyze the risk factors of pressure injury (PI) in critically ill patients with cancer to build a risk prediction model for PI. MATERIAL AND METHODS Between January 2018 and December 2019, a total of 486 critically ill patients with cancer were enrolled in the study. Univariate analysis and binary logistic regression analysis were used to explore risk factors. Then, a risk prediction equation was constructed and a receiver operator characteristic (ROC) curve analysis model was used for prediction. RESULTS Of the 486 critically ill patients with cancer, 15 patients developed PI. Risk factors found to have a significant impact on PI in critically ill patients with cancer included the APACHE II score (P<0.001), semi-reclining position (P=0.006), humid environment/moist skin (P<0.001), and edema (P<0.001). These 4 independent risk factors were used in the regression equation, and the risk prediction equation was constructed as Z=0.112×APACHE II score +2.549×semi-reclining position +2.757×moist skin +1.795×edema-9.086. From the ROC curve analysis, the area under the curve (AUC) was 0.938, sensitivity was 100.00%, specificity was 83.40%, and Youden index was 0.834. CONCLUSIONS The PI risk prediction model developed in this study has a high predictive value and provides a basis for PI prevention and treatment measures for critically ill patients with cancer.

Carbocation versus Carbene Controlled Chemoselectivity: DFT Study on Gold- and Silver-Catalyzed Alkylation/Cyclopropanation of Indoles with Vinyl Diazoesters.

Density functional theory calculations were performed to investigate the catalyst-controlled selective functionalization of indoles with vinyl diazoacetates. The detailed reaction mechanism was established, and different roles of carboncation or carbene intermediates in defining an experimentally observed chemo- and regioselectivity were fully rationalized.

The DFT Quest for Possible Reaction Pathways, Catalytic Species, and Regioselectivity in the InCl3-Catalyzed Cycloaddition of N-Tosyl Formaldimine with Olefins or Allenes.

The present work focuses on a theoretical investigation of the plausible mechanism, determination of catalytically active species, and understanding of the regioselectivity in the InCl3-catalyzed cycloaddition of N-tosyl formaldimine with alkenes or allenes. InCl3 and InCl2+ coordinated by dichloroethane (InCl2+-DCE) were investigated as model catalytic systems. DFT data supported that InCl2+-DCE represent the plausible in situ generated catalytic species. The catalytic cycle starts from the coordination of N-tosyl formaldimine to InCl2+-DCE, generating an In-complexed iminium intermediate. This then undergoes intermolecular reaction (aza-Prins) with alkene substrate to form a carbocation intermediate, which is chemoselectively attacked by the second N-tosyl formaldimine molecule to form a formaldiminium intermediate. In a final step, this intermediate undergoes the ring closure, leading to hexahydropyrimidine along with the regeneration of catalyst. In addition, our DFT results indicate that N-tosyl formaldimine not only acts as a reactant but also accelerates the 1,3-H-shift as a proton acceptor, giving an experimentally observed allylamide product. Also, the "iminium/alkene/imine" path was supported by calculation results for diastereoselective [2 + 2 + 2] reaction using an internal alkene. Finally, the regioselectivity of the InCl3-catalyzed cycloaddition using allenes along with N-tosyl formaldimine was also analyzed.

Function-Oriented: The Construction of Lanthanide MOF Luminescent Sensors Containing Dual-Function Urea Hydrogen-Bond Sites for Efficient Detection of Picric Acid.

Two novel lanthanide metal-organic framework (Ln-MOF) luminescent sensors for the detection of picric acid have been successfully assembled. Following a function-oriented strategy, urea hydrogen-bonding functional sites were introduced into two MOF frameworks. A structural analysis indicated that the two MOFs have the exact same structure, namely 2D layers with diamond-shaped holes that are accumulated into a 3D framework through the hydrogen-bonding interactions between urea and carboxylate groups. Interestingly, only half of the urea units are involved in supporting the MOF framework through N-H⋅⋅⋅O hydrogen-bonding interactions, whereas the other half are located in the pore channel and act as empty recognition sites. Abundant N-H urea bonds are present in the inner walls of three types of interpenetrating 1D channels. Luminescence studies revealed that the two Ln-MOFs exhibit high sensitivity, good selectivity, and a fast luminescence quenching response towards picric acid. In particular, the two Ln-MOFs can be simply and quickly regenerated, and exhibit excellent recyclability. In summary, we have successfully used a function-oriented strategy to achieve multiple functions in a ligand to construct lanthanide MOF luminescent sensors for the detection of picric acid, thereby providing a potential strategy for the future development of MOF luminescent sensors with a specific target.

Multifunctional Ln-MOF Luminescent Probe for Efficient Sensing of Fe3+, Ce3+, and Acetone.

A new series of five three-dimensional Ln(III) metal-organic frameworks (MOFs) formulated as [Ln4(µ6-L)2(µ-HCOO)(µ3-OH)3(µ3-O)(DMF)2(H2O)4] n {Ln3+ = Tb3+ (1), Eu3+ (2), Gd3+ (3), Dy3+ (4), and Er3+ (5)} was successfully obtained via a solvothermal reaction between the corresponding lanthanide(III) nitrates and 2-(6-carboxypyridin-3-yl)terephthalic acid (H3L). All of the obtained compounds were fully characterized, and their structures were established by single-crystal X-ray diffraction. All products are isostructural and possess porous 3D networks of the fluorite topological type, which are driven by the cubane-like [Ln4(µ3-OH)3(µ3-O)(µ-HCOO)]6+ blocks and µ6-L3- spacers. Luminescent and sensing properties of 1-5 were investigated in detail, revealing a unique capability of Tb-MOF (1) for sensing acetone and metal(III) cations (Fe3+ or Ce3+) with high efficiency and selectivity. Apart from a facile recyclability after sensing experiments, the obtained Tb-MOF material features a remarkable stability in a diversity of environments such as common solvents, aqueous solutions of metal ions, and solutions with a broad pH range from 4 to 11. In addition, compound 1 represents a very rare example of the versatile Ln-MOF probe capable of sensing Ce3+ or Fe3+ cations or acetone molecules.

Computational Exploration of Counterion Effects in Gold(I)-Catalyzed Cycloisomerization of ortho-(Alkynyl)styrenes.

A detailed theoretical analysis of the mechanism and chemoselectivity for gold(I)-catalyzed reaction of o-(alkynyl)styrene containing an isopropyl and a methyl at the terminal position of the alkene has been reported in this work. Two different counterions (SbF6 - and OTs-) were studied as model catalysts. According to our calculation, for SbF6 -, the reaction pathway is more prone to direct 1,2-H shifts (isopropyl H) than the elimination and ring expansion pathway. However, an elimination pathway affords the indenyl derivative by forming p-toluenesulfonic acid (HOTs), which may be the main pathway in the presence of OTs-. The chemoselectivity for the title reaction is mainly determined by the electronic effect of the counterion and the substituent rather than the steric effect. In other words, less basic SbF6 - mainly provides the charge separation effect rather than assisted proton elimination. However, the more basic OTs- mainly assist proton elimination through the formation of HOTs. In addition to the good agreement with the experimental data, the density functional theory results also provide a significant contribution to the understanding of the reaction mechanism.

Novel double layer lanthanide metal-organic networks for sensing applications.

A trifunctional aromatic building block (H2L) containing three different types of functional groups (carboxyl C([double bond, length as m-dash]O)OH, aldehyde C([double bond, length as m-dash]O)H, and O-ether) was applied for the hydrothermal synthesis of two novel lanthanide 2D coordination polymers [Ln(µ-HL)(µ3-L)(phen)]n {Ln = Tb (1) and Eu (2); H2L = 5-methoxy-(4-benzaldehyde)-1,3-benzene dicarboxylic acid; phen = 1,10-phenanthroline}. Both compounds 1 and 2 are isostructural and reveal very complicated 2D metal-organic double layers with the 3,4L27 topology. The presence of free aldehyde groups positioned outside of the double layers opens up a possibility of using them as functional groups toward sensing amines and small organic molecules. The fluorescence measurements for the Tb derivative 1 reveal that it acts as an efficient fluorescence sensor for p-phenylenediamine, benzidine and acetone molecules via a luminescence quenching effect. A similar sensing behavior was observed for the Eu compound 2. Moreover, thin-films of 1-PEG on glass (1-PEG-glass thin-film material) were fabricated and investigated for the detection of amine vapors.

New lanthanide(iii) coordination polymers: synthesis, structural features, and catalytic activity in CO2 fixation.

A new series of lanthanide coordination polymers formulated as [Ln(µ-L)(µ3-L)(H2O)]nXn (Ln/X = Er/Cl (1), Er/Br (2), Tm/Cl (3), Tm/Br (4), Yb/Cl (5), and Yb/Br (6); L = 1,3-bis(4-carboxyphenyl) imidazolium carboxylate(1+)) were solvothermally generated and fully characterized. Single-crystal X-ray diffraction analysis shows that all products possess isomorphous structures that are composed of cationic 1D double chains with encapsulated halide anions. From a topological perspective, such 1D chains can be classified as a binodal 3,5-connected net with a unique topology defined by the point symbol of (3·42)(32·42·53·62·7). All products 1-6 feature a remarkable thermal stability and were applied as highly active heterogeneous catalysts for the coupling reactions between halogenated propylene oxides and CO2 to give the corresponding cyclic carbonates. The reaction conditions, substrate and catalyst scope, and mechanistic features of this catalytic transformation were investigated. High products yields (up to 98%), elevated TONs (up to 3920) or TOFs (up to 326 h-1) were attained under mild reaction conditions. In addition, catalyst 6 can be recycled at least eight times with no loss of catalytic activity.

Hybrid materials based on novel 2D lanthanide coordination polymers covalently bonded to amine-modified SBA-15 and MCM-41: assembly, characterization, structural features, thermal and luminescence properties.

Three novel 2D coordination polymers [Tb2(µ4-L)2(µ-HL)(µ-HCOO)(DEF)]n (Tb-L), [Eu(µ4-L)(L)(H2O)2]n (Eu-L), and [Nd(µ4-L)(L)(H2O)2]n (Nd-L) were assembled from the corresponding lanthanide(iii) nitrates and 5 methoxy-(4-benzaldehyde)-1,3-benzenedicarboxylic acid (H2L) as a main multifunctional building block bearing carboxylate and aldehyde functional groups, using H2O/DEF {DEF = N,N-diethylformamide} as a reaction medium. The obtained coordination polymers were isolated as stable microcrystalline solids and fully characterized by elemental analysis, FT-IR spectroscopy, TGA, BET, PXRD, and single-crystal X-ray diffraction methods. Their structures feature intricate 2D metal-organic networks, which were topologically classified as underlying layers with the 4,6L26 (for Tb-L) or sql (for Eu-L and Nd-L) topologies. Besides, a novel series of mesoporous hybrid materials wherein the Tb-L, Eu-L, or Nd-L coordination polymers are covalently grafted into the amine-functionalized SBA-15-NH2 or MCM-41-NH2 matrices (via the formation of Schiff-base groups) was also synthesized and fully characterized. These hybrid materials show high thermal and photoluminescence stability, as well as remarkable chemical resistance to boiling water, and acidic or alkaline medium. Luminescent properties of the parent coordination polymers and derived hybrid materials are investigated in detail, showing that the latter combine the luminescent characteristics (intense green or red emissions and excellent stability) of lanthanide coordination polymers and structural features of ordered mesoporous silica molecular sieves. Moreover, light emitting devices were assembled, by coating the hybrid materials onto the surface of UV-LED bulbs, and showed excellent light emitting properties.

A Multi-responsive Regenerable Europium-Organic Framework Luminescent Sensor for Fe3+ , CrVI Anions, and Picric Acid.

A novel luminescent microporous lanthanide metal-organic framework (Ln-MOF) based on a urea-containing ligand has been successfully assembled. Structural analysis revealed that the framework features two types of 1D channels, with urea N-H bonds projecting into the pores. Luminescence studies have revealed that the Ln-MOF exhibits high sensitivity, good selectivity, and a fast luminescence quenching response towards Fe3+ , CrVI anions, and picric acid. In particular, in the detection of Cr2 O72- and picric acid, the Ln-MOF can be simply and quickly regenerated, thus exhibiting excellent recyclability. To the best of our knowledge, this is the first example of a multi-responsive luminescent Ln-MOF sensor for Fe3+ , CrVI anions, and picric acid based on a urea derivative. This Ln-MOF may potentially be used as a multi-responsive regenerable luminescent sensor for the quantitative detection of toxic and harmful substances.