Efficient Lead Removal by Assembly of Bio-Derived Ellagate Framework, Which Enables Electrocatalytic Reduction of CO2 to Formate.

Lead (Pb) poisoning and CO2-induced global warming represent two exemplary environmental and energy issues threatening humanity. Various biomass-derived materials are reported to take up Pb and convert CO2 electrochemically into low-valent carbon species, but these works address the problems separately rather than settle the issues simultaneously. In this work, cheap, natural ellagic acid (EA) extracted from common plants is adopted to assemble a stable metal-organic framework (MOF), EA-Pb, by effective capture of Pb2+ ions in an aqueous medium (removal rate close to 99%). EA-Pb represents the first structurally well-defined Pb-based MOF showing selective electrocatalytic CO2-to-HCOO- conversion with Faradaic efficiency (FE) of 95.37% at -1.08 V versus RHE. The catalytic mechanism is studied by 13CO2 labeling, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and theoretical calculation. The use of EA-Pb as an electrocatalyst for CO2 reduction represents a 2-in-1 solution of converting detrimental wastes (Pb2+) as well as natural resources (EA) into wealth (electrocatalytic EA-Pb) for addressing the global warming issue.

Linker Deficiency, Aromatic Ring Fusion, and Electrocatalysis in a Porous Ni8-Pyrazolate Network.

The cruciform linker molecule here features two designer functions: the pyrazole donors for framework construction, and the vicinal alkynyl units for benzannulation to form nanographene units into the Ni8-pyrazolate scaffold. Unlike the full 12 connections of the Ni8(OH)4(H2O)2 clusters in other Ni8-pyrazolate networks, significant linker deficiency was observed here, leaving about half of the Ni(II) sites capped by acetate ligands, which can be potentially removed to open the metal sites for reactivity. The crystalline Ni8-pyrazolate scaffold also retains the crystalline order even after thermal treatments (up to 300 °C) that served to partially graphitize the neighboring alkyne units. The resultant nanographene components enhance the electroactive properties of the porous hosts, achieving hydrogen evolution reaction (HER) activity that rivals that of topical nickel/palladium-enabled materials.

Structure, Luminescent Sensing and Proton Conduction of a Boiling-Water-Stable Zn(II) Metal-Organic Framework.

A novel Zn(II) metal-organic framework [Zn4O(C30H12F4O4S8)3]n, namely ZnBPD-4F4TS, has been constructed from a fluoro- and thiophenethio-functionalized ligand 2,2',5,5'-tetrafluoro-3,3',6,6'-tetrakis(2-thiophenethio)-4,4'-biphenyl dicarboxylic acid (H2BPD-4F4TS). ZnBPD-4F4TS shows a broad green emission around 520 nm in solid state luminescence, with a Commission International De L'Eclairage (CIE) coordinate at x = 0.264, y = 0.403. Since d10-configured Zn(II) is electrochemically inert, its photoluminescence is likely ascribed to ligand-based luminescence which originates from the well-conjugated system of phenyl and thiophenethio moieties. Its luminescent intensities diminish to different extents when exposed to various metal ions, indicating its potential as an optical sensor for detecting metal ion species. Furthermore, ZnBPD-4F4TS and its NH4Br-loaded composite, NH4Br@ZnBPD-4F4TS, were used for proton conduction measurements in different relative humidity (RH) levels and temperatures. Original ZnBPD-4F4TS shows a low proton conductivity of 9.47 × 10-10 S cm-1 while NH4Br@ZnBPD-4F4TS shows a more than 25,000-fold enhanced value of 2.38 × 10-5 S cm-1 at 40 °C and 90% RH. Both of the proton transport processes in ZnBPD-4F4TS and NH4Br@ZnBPD-4F4TS belong to the Grotthuss mechanism with Ea = 0.40 and 0.32 eV, respectively.

A Bumper Crop of Boiling-Water-Stable Metal-Organic Frameworks from Controlled Linker Sulfuration.

The series of highly stable porous solids here feature systematic, regiospecific sulfur substitutions on the organic linkers for versatile functions. One major surprise lies in the controllable sequential reactions between sodium thiomethoxide (NaSMe) and octafluorobiphenyl-4,4'-dicarboxylic acid (H2bpdc-8F; this was readily made without precious metal catalysts). Namely, 3, 4, 6, and 8 methylthio-substitutions can be respectively achieved with regiospecificity (i.e., to produce the four molecules H2bpdc-3S5F, H2bpdc-4S4F, H2bpdc-6S2F, H2bpdc-8MS). A second surprise lies in their persistent formation of the UiO-67-type net with Zr(IV) ions, e.g., even in the case of the fully sulfurated H2bpdc-8MS. In addition to the remarkable breadth of functional control, all the Zr(IV)-based crystalline solids here are stable in boiling water (e.g., for 24 h) and in air as solventless, activated porous solids. Moreover, the thioether groups allow for convenient H2O2 oxidation to fine-tune the hydrophilicity and luminescence properties and improve proton conductivity.

Single-Phase White-Light-Emitting and Photoluminescent Color-Tuning Coordination Assemblies.

Metal-organic complexes assembled from coordinative interactions are known to be able to display a wide range of photoluminescent behaviors benefiting from an extensive number of metal ions, organic linkers, and inclusion guests, depending on the multifaceted nature of their chemical structures and photophysical properties. In the past two decades, the white-light-emitting (WLE) and photoluminescent color-tuning (PLCT) materials based on the single-phase metal-organic coordination assemblies have merited particular attention and gained substantial advances. In this review, we give an overview of recent progress in this field, placing emphasis on the WLE and PLCT properties realized in the single-phase materials, which covers the origin, generation, and manipulation of different types of photoluminescence (PL) derived from ligand-centered (LC), metal/cluster-centered (MC or CC), excimer/exciplex-based (EX), metal-to-ligand or ligand-to-metal charge-transfer-based (MLCT or LMCT), or guest-included emissions. The coordination assemblies in this topic can be generally classified into three categories [(1) mono/homometallic coordination assemblies based on main group (s,p-block), transition (d-block), or lanthanide (f-block) metal centers, (2) s/p-f-, d-f-, or f-f-type heterometallic coordination assemblies, and (3) guest-included coordination assemblies] for which WLE and PLCT properties can be achieved by virtue of either a wide-band/overlapped emission covering the whole visible spectrum from a single emitting center or a combination of complementary color emissions from multiple emitting centers/origins. Some state-of-the-art assembly methods and successful design models relevant to the above three categories are elaborated to demonstrate how to achieve efficient and controllable white-light emission in a single-phase material through a tunable PL approach. Potential applications in the fields of lighting and displaying, sensing and detecting, and barcoding and patterning are surveyed, and at the end, possible prospects and challenges for future development along this line are proposed.

MicroRNA-193b-3p regulates matrix metalloproteinase 19 expression in interleukin-1ß-induced human chondrocytes.

Micro(mi)RNAs are small, non-coding RNA molecules known to play a significant role in osteoarthritis (OA) initiation and development, and similar to matrix metalloproteinases (MMPs), they participate in cartilage degeneration and cleave multiple extracellular matrices. The aim of this study was to determine whether the expression of MMP-19 in interleukin (IL)-1ß-induced human chondrocytes is directly regulated by miR-193b-3p. Expression levels of miR-193b-3p and MMP-19 in normal and osteoarthritis (OA) human cartilage, and interleukin-1 ß (IL-1ß)-induced human chondrocytes were determined by real-time polymerase chain reaction. Additionally, expression level of MMP-19 in IL-1ß-induced human chondrocytes was estimated by Western blotting and immunohistochemistry analyses. The effect of miR-193b-3p on MMP-19 expression was evaluated using transient transfection of normal human chondrocytes with miR-193b-3p mimic or its antisense inhibitor (miR-193b-3p inhibitor), and siMMP-19. The putative binding site of miR-193b-3p in the 3'-untranslated region (UTR) of MMP-19 mRNA was validated by luciferase reporter assay. miR-193b-3p expression was reduced in OA cartilage compared to that in normal chondrocytes, while the opposite was observed for MMP-19. Upregulation of MMP-19 expression was correlated with downregulation of miR-193b-3p in IL-1ß-stimulated normal chondrocytes. Increase in miR-193b-3p levels was associated with silencing of MMP-19. Overexpression of miR-193b-3p suppressed the activity of the reporter construct containing the 3'-UTR of human MMP-19 mRNA and inhibited the IL-1ß-induced expression of MMP-19 and iNOS in chondrocytes, while treatment with miR-193b-3p inhibitor enhanced MMP-19 expression. MiR-193b-3p is an important regulator of MMP-19 in human chondrocytes and may relieve the inflammatory response in OA.

An injectable, biodegradable calcium phosphate cement containing poly lactic-co-glycolic acid as a bone substitute in ex vivo human vertebral compression fracture and rabbit bone defect models.

Purpose/Aim of the study: To evaluate the biomechanical characteristics and biocompatibility of an injectable, biodegradable calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA). MATERIALS AND METHODS: A vertebral compression fracture model was established using 20 human cadaveric vertebrae (T11-L3) divided into CPC/PLGA composite versus PMMA groups for biomechanical testing. In addition, 35 New Zealand rabbits were used to evaluate biodegradability and osteoconductive properties of CPC/PLGA using a bone defect model. In vitro cytotoxicity was evaluated by culturing with L929 cells. RESULTS: The CPC/PLGA composite effectively restored vertebral biomechanical properties. Compared with controls, the maximum load and compression strength of the CPC/PLGA group were lower, and stiffness was lower after kyphoplasty (all p <.05). Degradation was much slower in the control CPC compared with CPC/PLGA group. The bone tissue percentage in the CPC/PLGA group (44.9 ± 23.7%) was significantly higher compared with control CPC group (25.7 ± 10.9%) (p <.05). The viability of cells cultured on CPC/PLGA was greater than 70% compared with the blanks. CONCLUSIONS: Our biodegradable CPC/PLGA composite showed good biomechanical properties, cytocompatibility, and osteoconductivity and may represent an ideal bone substitute for future applications.

Semiconductive Amine-Functionalized Co(II)-MOF for Visible-Light-Driven Hydrogen Evolution and CO2 Reduction.

A Co-MOF, [Co3(HL)2·4DMF·4H2O] was simply synthesized through a one-pot solvothermal method. With the semiconductor nature, its band gap was determined to be 2.95 eV by the Kubelka-Munk method. It is the first trinuclear Co-MOF employed for photocatalytic hydrogen evolution and CO2 reduction with cobalt-oxygen clusters as catalytic nodes. Hydrogen evolution experiments indicated the activity was related to the photosensitizer, TEOA, solvents, and size of catalyst. After optimization, the best activity of H2 production was 1102 µmol/(g h) when catalyst was ground and then soaked in photosensitizer solution before photoreaction. To display the integrated design of Co-MOF, we used no additional photosensitizer and cocatalyst in the CO2 reduction system. When -NH2 was used for light absorption and a Co-O cluster was used as catalyst, Co-MOF exhibited an activity of 456.0 µmol/(g h). The photocatalytic mechanisms for hydrogen evolution and CO2 reduction were also proposed.

Expression patterns of transcription factor PPARγ and C/EBP family members during in vitro adipogenesis of human bone marrow mesenchymal stem cells.

In the past decades increasing lines of evidence have demonstrated that adipose tissue, as an endocrine organ plays a central role in metabolic homeostasis and its related maladies. CCAAT/enhancer-binding protein (C/EBP) family members and the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) were known to be the vital transcription factors in the regulation of adipogenesis. However, the exact mechanism for increased marrow fat in patients with bone metabolic diseases, such as osteoporosis, is still poorly understood. Herein, we studied the expression pattern of PPARγ and C/EBPs in human bone marrow mesenchymal stem cell (hBMSC) adipogenesis and evaluated the effects of individual components of an adipogenic cocktail on the differentiation and transcription factor expression. We furthermore examined whether the ERK signaling pathway was involved in mediating these effects. These findings showed that C/EBPß and C/EBPδ were detected in undifferentiated hBMSC and maintained during the whole process of adipogenesis, and could initiate the expression of PPARγ1 under the treatment of dexamethasone and IBMX. Subsequently, the activation of PPARγ1 by indomethacin, its exogenous ligand, activated C/EBPα, which, together with IBMX, up-regulated PPARγ2 expression and therefore the fullest adipogenesis. Insulin and its downstream signal pathway extracellular signal-regulated kinases (ERK), however, were found not necessary for hBMSC adipogenesis. Our results revealed some unique characteristics of human adipocyte formation, which may help to understand the molecular mechanisms of bone marrow adipogenesis and give insights into the treatment of osteoporosis.

Blood transfusion and drainage catheter clamping are associated with ecchymosis formation at the surgical site after total knee arthroplasty: an analysis of 102 unilateral cases.

BACKGROUND: Many previous studies have focused on the postoperative complication of postoperative knee pain, infection, knee prosthesis loosening, periprosthetic fractures, and so on. There have been few studies focused on postoperative ecchymosis formation surrounding the wound of the TKA site. A certain degree of effect on the early functional recovery of the patients may occur due to the mental stress caused by the ecchymosis, which raises doubts regarding the success of the surgery. Therefore, it is particularly important to understand the risk factors for postsurgical ecchymosis formation after TKA, and specific measures for preventing ecchymosis should be taken. In this study, we reviewed the record of patients who received TKAs in our hospital, and a comprehensive analysis and assessment was conducted regarding 15 clinical factors causing postsurgical ecchymosis formation. METHODS: The records of 102 patients who received unilateral TKAs between January 2007 and May 2010 were retrospectively analyzed. Patients were divided into two groups based on the occurrence of ecchymosis. RESULTS: Of the 102 patients, 14 (13.7%) developed ecchymosis. Blood transfusion and drainage catheter clamping during the first few postoperative hours had a significant impact on the development of ecchymosis (p < 0.05). There was no difference in age, BMI, operation time, pre- and postoperative platelet count, and length of postoperative anticoagulant therapy between the two groups. Multivariate logistic regression revealed major risk factors for ecchymosis were postoperative blood transfusion (odds ratio (OR) = 15.624) and drainage catheter clamping (OR 14.237) (both, p < 0.05). CONCLUSION: Blood transfusion and drainage catheter clamping after TKA due to excessive blood suction were associated with higher risks for ecchymosis formation surrounding the surgical site.

Total hip arthroplasty for vascular necrosis of the femoral head in patients with systemic lupus erythematosus: a midterm follow-up study of 28 hips in 24 patients.

OBJECTIVE: Avascular necrosis of the femoral head is one of the most frequently reported complications in patients with systemic lupus erythematosus (SLE) and often requires total hip arthroplasty (THA). Our objective was to analyze the perioperative management, technical problems, clinical outcomes, and complications associated with THA in patients with SLE. METHODS: A total of 28 total hip arthroplasties performed for 24 patients with SLE, including 19 women and 5 men with a mean age of 38.8 years performed from 1998 to 2011 were retrospectively reviewed. SLE disease activity index and ASA class were evaluated preoperatively. WOMAC, HHS, and SF-36 scores were also evaluated in all cases pre- and post-operatively for functional recovery of the hip and health-related quality of life (HRQOL). RESULTS: The average SLE disease activity index was 3.5 points. Three patients were in ASA class I, 12 class II, and 9 were class III (37.5%). The average duration of follow-up was 67.5 months. None of the patients required a revision, and 3 patients died during the follow-up period. A statistically significant improvement in all scores was found comparing pre- and post-operative conditions (P < 0.001). The complication rate was 11.1% with 2 wound infections and 1 urinary tract infection. CONCLUSION: THA is an acceptable method for achieving functional recovery and increasing HRQOL in patients with SLE and ANFH who receive proper perioperative management.

miRNA expression profile during osteogenic differentiation of human adipose-derived stem cells.

Human adipose-derived stem cells (hADSC) are capable of differentiating into an osteogenic lineage. It is believed that microRNAs (miRNAs) play important roles in regulating this osteogenic differentiation of human adipose-derived cells, although its molecular mechanism remains unclear. We investigated the miRNA expression profile during osteogenic differentiation of hADSCs, and assessed the roles of involved miRNAs during the osteogenic differentiation. We obtained and cultured human adipose-derived stems cells from donors who underwent elective liposuction or other abdominal surgery at our institution. miRNA expression profiles pre- and post-osteogenic induction were obtained using microarray essay, and differently expressed miRNAs were verified using quantitative real-time polymerase chain reaction (qRT-PCR). The expression of osteogenic proteins was detected using an enzyme-linked immunosorbent assay. Putative targets of the miRNAs were predicted using online software MiRanda, TargetScan, and miRBase. Eight miRNAs were found differently expressed pre- and post-osteogenic induction, among which four miRNAs (miR-17, miR-20a, miR-20b, and miR-106a) were up-regulated and four miRNAs (miR-31, miR-125a-5p, miR-125b, and miR-193a) were down-regulated. qRT-PCR analysis further confirmed the results. Predicted target genes of the differentially expressed miRNAs based on the overlap from three public prediction algorithms: MiRanda, TargetScan, and miRBase Target have the known functions of regulating stem cell osteogenic differentiation, self-renewal, signal transduction, and cell cycle control. We identified a group of miRNAs that may play important roles in regulating hADSC cell differentiation toward an osteoblast lineage. Further study of these miRNAs may elucidate the mechanism of hADSC differentiation into adipose tissue, and thus provide basis for tissue engineering.

The influence of body mass index on life quality and clinical improvement after total hip arthroplasty.

BACKGROUND: The effect of body mass index (BMI) on the outcome of total hip arthroplasty (THA) remains controversial. The purpose of this study was to examine whether revision rate and postoperative outcomes following THA were influenced by BMI. MATERIALS AND METHODS: We retrospectively evaluated 714 patients (751 hips) who underwent primary THA in our department between March 1991 and April 2006. They were followed prospectively for 5-20 years with 24 deaths (24 hips) and 33 losses (34 hips). Patients were separated into three groups based on BMI: underweight, normal and obese groups. A survival analysis was performed using revision as the endpoint, and a case-matched study that was matched for age, gender, and laterality was designed; outcomes were assessed with the Harris Hip score, 36-item short-form health survey, complication rate and radiological examination. RESULTS: The preoperative scores were lower for the obese group, and the postoperative scores were higher for the normal group. Patients in the obese group obtained the greatest overall improvement in clinical scores from admission to the last follow-up. We found a significantly higher complication rate in the obese group and underweight group. It appears that being underweight was associated with an increased dislocation rate, and obese patients were more likely to have osteolysis, deep vein embolism, and pulmonary thrombosis. The log rank test for survival showed no significant differences among the three groups. CONCLUSIONS: Abnormal BMI does not prevent functional rehabilitation after THA; however, patients with abnormal BMI have to face higher complication rates and poorer clinical outcomes following this operation.

Impaction Bone Grafting Combined with Titanium Mesh for Acetabular Bone Defects Reconstruction in Total Hip Arthroplasty Revision: A Retrospective and Mini-Review Study.

OBJECTIVE: To investigate the application of impaction bone grafting (IBG) combined with Ti-alloy mesh for acetabular bone defect reconstruction in total hip arthroplasty (THA) revision and follow up the clinical outcomes and imaging findings. METHODS: The clinical and imaging data of patients who were admitted to our hospital from January 2000 to December 2020 and underwent acetabular bone defects reconstruction using IBG combined with titanium mesh were retrospectively analyzed. Preoperative and post-revision Oxford and Harris scores, and post-revision complications were evaluated. Radiographs were used to determine center of rotation (COR) of the hip joint, transparency line, bone graft fusion, and bone mineral density (BMD) around the hip joint. RESULTS: Significant improvement was observed in both Oxford and Harris scores (P < 0.05). The radiographs taken at the last follow-up examination showed no significant differences in the acetabulum COR, offsets, inclination angle, mean ratio of vertical value, and BMD analysis between the post-revision side and contralateral side (P > 0.05). The follow-up data showed restoration of the mesh implant and graft bone fusion. CONCLUSIONS: The application of IBG combined with titanium-alloy mesh in revision THA patients with acetabular defects was found to provide satisfactory outcomes. However, large-scale studies are still needed to further elucidate the long-term outcomes.

Conjugated crosslinks boost the conductivity and stability of a single crystalline metal-organic framework.

A linker molecule with four pendant thiophene functions was crystallized with Zr(iv) ions to form a semiconductive porous coordination solid (1.1 × 10-5 S cm-1). Oxidative treatment with FeCl3 guests then coupled the thiophene units to form conjugated bridges as covalent crosslinks. The resulting hybrid of a metal-organic framework and conjugated polymer featured robust crystalline order that withstood long-term air exposure and broad pH (from 0 to 12) conditions. Moreover, the homocoupled thiophene units, conjugated through sulfide links (-S-) with the linker backbone, afforded higher electronic conductivity (e.g., >2.2 × 10-3 S cm-1), which is characteristic of conductive polymer prototypes of polythiophene and polyphenylene sulfide. The crosslinked solid also exhibited proton conductivity that could be increased broadly upon H2SO4 treatment (e.g., from 5.0 × 10-7 to 1.6 × 10-3 S cm-1).

[Clinical analysis of revision after primary hip replacement in the early stage].

OBJECTIVES: To analyze the reason of revisions no more than 5 years after primary hip replacement, and to discuss the methods how to prevent and manage. METHODS: Retrospectively review 11 cases with revision no more than 5 years after primary total hip replacement from January 2002 to June 2007. The reasons for revision were as follows: 2 cases were recurrent dislocation due to malposition of acetabular prosthesis; 5 cases were loosening of acetabular prosthesis; 1 case was abrasion of the native acetabulum by bipolar femoral head; 2 cases were periprosthetic femoral fractures and 1 case was periprosthetic infection. The average follow-up time was 36 months. Each patient was assessed according to Harris hip score. The revision procedures including liner only, acetabular prosthesis only, or both acetabular prosthesis and femoral prosthesis depending on the reasons for revision, two-stage revision was performed on 1 case with periprosthetic infection. RESULTS: The average of Harris hip score was increased from 46 (28 to 62) preoperatively to 86 (75 to 96) at follow up. The complication occurred in 2 cases: one was postoperative haematoma formation who was performed further surgery for clearance of haematoma, another was slight instability of the hip joint who was accepted skin traction for 3 weeks. CONCLUSIONS: The main reason for revision after primary total hip replacement is related to uncorrected insert of acetabular prosthesis. Improving surgical technique of insert of acetabular prosthesis is important in primary total hip replacement.

Conductive Metal-Organic Frameworks: Mechanisms, Design Strategies and Recent Advances.

Metal-organic frameworks (MOFs), constructed from metal ions and organic ligands through coordination assembly, exhibit considerable conductivity, which originates from the ionic or electronic transport pathway between the host architecture and guest species. In recent decades, the study of conductive MOFs has accelerated deservedly due to their importance in the electronic information industry. In this review, we first briefly describe the different mechanisms of ionic and electronic conduction. The design strategies of constructing intrinsic and doping MOFs are then summarized and generalized into three major categories (host-based-, guest-based- and host-guest-related systems) in terms of promoting conductive performance. In the next section we provide an overview of recent progress in research on conductive MOFs, providing details according to the various carriers of transporting electrons, protons and other ions. We conclude with a discussion on the practicability and emerging applications of conductive MOFs and a section on the existing challenges and development prospects. Conduction mechanisms, design strategies, recent progresses and emerging applications of conductive MOFs.

Effect of 3 different anticoagulants on hidden blood loss during total hip arthroplasty after tranexamic acid.

Comparison of different anticoagulants in blood management and complications with tranexamic acid (TXA) in total hip arthroplasty (THA) is unclear. Our aim was to compare the efficacy and safety among receiving nadroparin calcium, enoxaparin sodium or rivaroxaban after TXA in THA.150 patients undergoing primary unilateral THA were received 15 mg/kg intravenous TXA (IV-TXA) before skin incision, followed by 1 of nadroparin calcium (Group A), enoxaparin sodium (Group B), or rivaroxaban (Group C) randomly during hospitalization. The primary outcome was hidden blood loss (HBL). Other outcomes such as the maximum hemoglobin (Hb) drop, total blood loss (TBL), the volume of drainage, transfusion rate, length of hospital stay (LOS), and complications were also compared.There were no statistically significant differences in HBL, the maximum hemoglobin (Hb) drop, transfusion rate, and complications among 3 groups. LOS was significantly higher for patients in Group B than Group A (P = .026). Neither deep venous thrombosis (DVT) nor pulmonary embolism (PE) occurred in any group.There were no differences in efficacy and safety in patients undergoing THA receiving nadroparin calcium, enoxaparin sodium, or rivaroxaban after anti-fibrinolysis with TXA.

An air-stable anionic two-dimensional semiconducting metal-thiolate network and its exfoliation into ultrathin few-layer nanosheets.

The black, small-bandgap semiconducting framework Eu-dfdmat features extensive Eu3+-sulfur bridges from the linear linker 2,5-difluoro-3,6-dimercaptoterephthalate (dfdmt). Each Eu center is chelated to four dfdmt linkers to form an anionic coordination sphere involving four carboxyl O and four mercapto S centers (EuO4S4), wherein the charge buildup can be alleviated by the electron-withdrawing fluoro groups. The extensive metal-linker bonding, together with a trace of Eu2+ species, appears to boost electronic interaction in the 2D net, generating a small band gap of 1.31 eV (946 nm), albeit a modest conductivity (e.g., 10-6 S m-1). The crystals also exhibit persistent EPR signals indicative of organic radicals (g = 2.002). The Eu-dfdmt solid are stable in air and can be exfoliated into ultrathin nanosheets (ca. 5 nm; 6-8 layers).

Acidity and Cd2+ fluorescent sensing and selective CO2 adsorption by a water-stable Eu-MOF.

A new Eu-MOF was designed from an amino-functionalized ligand and Eu(iii) ions under solvothermal conditions. It is a highly porous, water-stable, and luminescent material, exhibiting pH sensing in the acidic range of pH = 7-3 with selective detection for Cd2+ by an enhanced fluorescence of ∼23-fold against a series of metal ions. Gas adsorption performance shows that Eu-MOF exhibits a high CO2/N2 (15/85) selectivity of 109.4 at 273 K and 1 atm. This performance was superior to that of most reported Ln-MOFs owing to its appropriate pore size, dipole-dipole interaction and donor-acceptor Lewis affinities.