Establishment and validation of an artificial intelligence web application for predicting postoperative in-hospital mortality in patients with hip fracture: a National cohort study of 52,707 cases.

BACKGROUND: In-hospital mortality following hip fractures is a significant concern, and accurate prediction of this outcome is crucial for appropriate clinical management. Nonetheless, there is a lack of effective prediction tools in clinical practice. By utilizing artificial intelligence and machine learning techniques, this study aims to develop a predictive model that can assist clinicians in identifying geriatric hip fracture patients at a higher risk of in-hospital mortality. METHODS: A total of 52,707 geriatric hip fracture patients treated with surgery from 90 hospitals were included in this study. The primary outcome was postoperative in-hospital mortality. The patients were randomly divided into two groups, with a ratio of 7:3. The majority of patients, assigned to the training cohort, were used to develop the AI models. The remaining patients, assigned to the validation cohort, were used to validate the models. Various machine learning algorithms, including logistic regression (LR), decision tree (DT), naïve Bayesian (NB), neural network (NN), eXGBoosting machine (eXGBM), and random forest (RF), were employed for model development. A comprehensive scoring system, incorporating 10 evaluation metrics, was developed to assess the prediction performance, with higher scores indicating superior predictive capability. Based on the best machine learning-based model, an AI application was developed on the Internet. In addition, a comparative testing of prediction performance between doctors and the AI application. FINDINGS: The eXGBM model exhibited the best prediction performance, with an AUC of 0.908 (95% CI: 0.881-0.932), as well as the highest accuracy (0.820), precision (0.817), specificity (0.814), and F1 score (0.822), and the lowest Brier score (0.120) and log loss (0.374). Additionally, the model showed favorable calibration, with a slope of 0.999 and an intercept of 0.028. According to the scoring system incorporating 10 evaluation metrics, the eXGBM model achieved the highest score (56), followed by the RF model (48) and NN model (41). The LR, DT, and NB models had total scores of 27, 30, and 13, respectively. The AI application has been deployed online at https://in-hospitaldeathinhipfracture-l9vhqo3l55fy8dkdvuskvu.streamlit.app/ , based on the eXGBM model. The comparative testing revealed that the AI application's predictive capabilities significantly outperformed those of the doctors in terms of AUC values (0.908 vs. 0.682, P <0.001). CONCLUSIONS: The eXGBM model demonstrates promising predictive performance in assessing the risk of postoperative in-hospital mortality among geriatric hip fracture patients. The developed AI model serves as a valuable tool to enhance clinical decision-making.

CHRONIC CRITICAL ILLNESS-INDUCED MUSCLE ATROPHY: INSIGHTS FROM A TRAUMA MOUSE MODEL AND POTENTIAL MECHANISM MEDIATED VIA SERUM AMYLOID A.

ABSTRACT: Background: Chronic critical illness (CCI), which was characterized by persistent inflammation, immunosuppression, and catabolism syndrome (PICS), often leads to muscle atrophy. Serum amyloid A (SAA), a protein upregulated in critical illness myopathy, may play a crucial role in these processes. However, the effects of SAA on muscle atrophy in PICS require further investigation. This study aims to develop a mouse model of PICS combined with bone trauma to investigate the mechanisms underlying muscle weakness, with a focus on SAA. Methods: Mice were used to examine the effects of PICS after bone trauma on immune response, muscle atrophy, and bone healing. The mice were divided into two groups: a bone trauma group and a bone trauma with cecal ligation and puncture group. Tibia fracture surgery was performed on all mice, and PICS was induced through cecal ligation and puncture surgery in the PICS group. Various assessments were conducted, including weight change analysis, cytokine analysis, hematological analysis, grip strength analysis, histochemical staining, and immunofluorescence staining for SAA. In vitro experiments using C2C12 cells (myoblasts) were also conducted to investigate the role of SAA in muscle atrophy. The effects of inhibiting receptor for advanced glycation endproducts (RAGE) or JAK2 on SAA-induced muscle atrophy were examined. Bioinformatic analysis was conducted using a dataset from the GEO database to identify differentially expressed genes and construct a coexpression network. Results: Bioinformatic analysis confirmed that SAA was significantly upregulated in muscle tissue of patients with intensive care unit-induced muscle atrophy. The PICS animal models exhibited significant weight loss, spleen enlargement, elevated levels of proinflammatory cytokines, and altered hematological profiles. Evaluation of muscle atrophy in the animal models demonstrated decreased muscle mass, grip strength loss, decreased diameter of muscle fibers, and significantly increased expression of SAA. In vitro experiment demonstrated that SAA decreased myotube formation, reduced myotube diameter, and increased the expression of muscle atrophy-related genes. Furthermore, SAA expression was associated with activation of the FOXO signaling pathway, and inhibition of RAGE or JAK2/STAT3-FOXO signaling partially reversed SAA-induced muscle atrophy. Conclusions: This study successfully develops a mouse model that mimics PICS in CCI patients with bone trauma. Serum amyloid A plays a crucial role in muscle atrophy through the JAK2/STAT3-FOXO signaling pathway, and targeting RAGE or JAK2 may hold therapeutic potential in mitigating SAA-induced muscle atrophy.

Effects of Endoscopic Sinus Surgery on Olfactory Bulb Volume among Patients with Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis.

BACKGROUND: Endoscopic sinus surgery (ESS) could significantly improve olfactory function among patients with chronic rhinosinusitis (CRS). This study aimed to perform a meta-analysis to evaluate the effect of ESS on the olfactory bulb volume (OBV) among patients with CRS. METHODS: A systemic search of PubMed, Medline, Embase, Web of Science, and other databases was conducted to identify studies assessing OBV changes in patients with CRS after ESS utilizing magnetic resonance imaging. RESULTS: A total of four studies with 168 participants were included. Comparing the changes in OBV of patients with CRS before and after surgery within 3-6 months, the ESS significantly improved the overall OBV (P = 0.005, I2 = 66%), with the left OBV increased by 5.57mm3 (P = 0.84, I2 = 0%), and the right OBV increased by 8.63mm3 (P = 0.09, I2 = 53%). A difference in OBV persists between healthy controls and patients with CRS 3-6 months after ESS. The overall OBV of patients with CRS after ESS was significantly smaller than controls (mean difference = -3.84, P = 0.04), with a mean difference of 4.13mm3 on the left side (P = 0.72, I2 = 0%), and a mean difference of 3.22mm3 on the right side (P = 0.0001, I2 = 89%). CONCLUSIONS: ESS significantly increases the OBV among patients with CRS.

Cholestyramine alleviates bone and muscle loss in irritable bowel syndrome via regulating bile acid metabolism.

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder known for its multifaceted pathogenesis and varied extraintestinal manifestations, yet its implications for bone and muscle health are underexplored. Recent studies suggest a link between IBS and musculoskeletal disorders, but a comprehensive understanding remains elusive, especially concerning the role of bile acids (BAs) in this context. This study aimed to elucidate the potential contribution of IBS to bone and muscle deterioration via alterations in gut microbiota and BA profiles, hypothesizing that cholestyramine could counteract these adverse effects. We employed a mouse model to characterize IBS and analysed its impact on bone and muscle health. Our results revealed that IBS promotes bone and muscle loss, accompanied by microbial dysbiosis and elevated BAs. Administering cholestyramine significantly mitigated these effects, highlighting its therapeutic potential. This research not only confirms the critical role of BAs and gut microbiota in IBS-associated bone and muscle loss but also demonstrates the efficacy of cholestyramine in ameliorating these conditions, thereby contributing significantly to the field's understanding and offering a promising avenue for treatment.

Extracellular vesicles produced by 3D cultured MSCs promote wound healing by regulating macrophage activation through ANXA1.

The conundrum of wound healing has transformed into an imminent medical challenge. Presently, cell-free therapy centered around extracellular vesicles (EVs) has become a pivotal and promising research avenue. EVs generated from three-dimensional (3D) cell cultures have been previously established to possess enhanced tissue regeneration potential, although the underlying mechanisms remain elusive. In this study, we observed higher expression of annexin ANXA1 in 3D-cultured EVs. Remarkably, 3D-EVs with elevated ANXA1 expression demonstrated a more potent capacity to promote macrophage polarization from the M1 phenotype to the M2 phenotype. Concurrently, they exhibited superior abilities to enhance cell migration and tube formation, facilitating expedited wound healing in animal experiments. Conversely, the application of an ANXA1 inhibitor counteracted the positive effects of 3D-EVs. Taken together, our data validate that extracellular vesicles derived from 3D-cultured MSCs regulate macrophage polarization via ANXA1, thereby fostering wound healing.

Functional chitosan gel coating enhances antimicrobial properties and osteogenesis of titanium alloy under persistent chronic inflammation.

Titanium is widely used as surgical bone implants due to its excellent mechanical properties, corrosion resistance, and good biocompatibility. However, due to chronic inflammation and bacterial infections caused by titanium implants, they are still at risk of failure in interfacial integration of bone implants, severely limiting their broad clinical application. In this work, chitosan gels crosslinked with glutaraldehyde were prepared and successfully loaded with silver nanoparticles (nAg) and catalase nanocapsules (n (CAT)) to achieve functionalized coating on the surface of titanium alloy steel plates. Under chronic inflammatory conditions, n (CAT) significantly reduced the expression of macrophage tumor necrosis factor (TNF-α), increased the expression of osteoblast alkaline phosphatase (ALP) and osteopontin (OPN), and enhanced osteogenesis. At the same time, nAg inhibited the growth of S. aureus and E. coli. This work provides a general approach to functional coating of titanium alloy implants and other scaffolding materials.

Association between cognition and olfaction-specific parameters in patients with chronic rhinosinusitis.

BACKGROUND: Patients with chronic rhinosinusitis (CRS) have reported significantly cognitive and olfactory dysfunction. This study aimed to explore the relationship between cognitive function and olfaction-specific parameters in patients with CRS. METHODS: A cross-sectional survey method was used to investigate 98 participants, including 75 patients with CRS and 23 healthy controls. Cognitive function and psychophysical olfactory tests were performed. Olfactory cleft endoscopy scale and olfactory cleft computed tomography (CT) scores were obtained. Multivariate logistic regression was used to analyze the risk factors of Mild Cognitive Impairment (MCI) in patients with CRS. RESULTS: There are significant differences in age, Montreal Cognitive Assessment (MoCA) scores, number of MCI, Lund-Mackay olfactory cleft (LM-OC) score, and blood eosinophil count between CRS with and without olfactory dysfunction groups (all P < 0.05). Total MoCA scores were positively correlated with thresholds-discrimination-identification (TDI) score (r = 0.541, P < 0.001), olfactory threshold (OT) (r = 0.440, P < 0.001), olfactory discrimination (OD) (r = 0.541, P < 0.001), and olfactory identification (OI) (r = 0.382, P = 0.001) scores. Furthermore, total MoCA scores were negatively correlated with LM-OC scores (r = - 0.351, P = 0.002). After adjusting for patient demographics, only the OD score was an independent risk factor for MCI among patients with CRS (odds ratio = 0.792; P = 0.039). The OD scores less than 11.5 were the best predictor of MCI in patients with CRS. CONCLUSION: Olfaction-specific clinical parameters were highly correlated with cognitive function in patients with CRS and the OD score was an independent risk factor for MCI in patients with CRS.

[The importance of intranasal trigeminal event-related potentials test for patients with olfactory dysfunction].

Objective: To analyze the characteristics of trigeminal event-related potentials (tERPs) in different kinds of olfactory disorders (OD), and to evaluate the importance of tERPs for the patients with olfactory dysfunction. Methods: Clinical data of 314 patients with olfactory dysfunction from the Smell and Taste Clinics in Beijing Anzhen Hospital from 2015 to 2021 were retrospectively reviewed, including 158 males and 156 females, aging from 6 to 78 years. The control group consisted of healthy people from medical examination center, who were gender and age matched. The clinical characteristics of OD were analyzed using Sniffin' Sticks test, olfactory event-related potentials (oERPs), tERPs and acoustic rhinometry test. SPSS 17.0 software was used to compare the difference of tERPs between the two groups, and to analyze the related factors affecting trigeminal function. Results: The ratio of tERPs presence was different in OD caused by different reasons: head traumatic OD (54.9%), post-virus infection OD (63.6%), sinonasal inflammatory OD (68.4%) and OD due to other causes (56.9%). Compared with controls, tERPs signals in OD patients showed a significant lower amplitude in the N1 wave (all P<0.001), and lower amplitude in the P2 wave in most OD patients (head trauma t=-4.11, P<0.001; sinonasal inflammation t=-2.04, P=0.046; others t=-2.40, P=0.020) except in OD by post-virus infection (t=-1.98, P=0.052). tERPs signals in OD patients by sinonasal inflammation showed longer latency in the N1 wave (t=2.15, P=0.036), but this difference was not observed in other OD patients (all P>0.05). tERPs signals were significantly correlated with the Sniffin' Sticks score, deficiency of oERPs and nasal minimum cross-sectional area (all P<0.05). Conclusions: OD patients show neurophysiologic deficits in trigeminal function. The absence of tERPs or lower amplitude in N1 waves are the important characteristics of patients with OD.

[Analysis of clinical characteristics in the patient with olfactory disorders].

Objective:To analyze the etiology and clinical features of patients with olfactory disorders （OD） , and to explore the importance of gustatory testing in patients with OD. Methods:Clinical data of 335 consecutive patients with OD who seek medical consultation in the smell and taste center from the year 2015 to 2021 was retrospectively analyzed. The clinical characteristics of patients with OD were analyzed thorough a structured interview of medical history, otolaryngologic examinations, olfactory tests（Sniffin' Sticks test） and gustatory function test（whole-mouth taste test）. SPSS 17.0 software was used to analyze the clinical characteristics of patients with OD and related factors which have effect on gustatory function. Results:Among the patients， 36.4% of them caused by head trauma, 22.1% for upper respiratory tract infection（URTI）, 15.5% for rhinosinusitis diseases（RSD）, 11.9% for idiopathic, 9.6% for congenital anosmia, and 4.5% for other causes, respectively. The features were different in patients with different kinds of OD: most patients with head trauma were anosmic（χ²=27.958, P<0.001）, and no difference was found in gender and age（P>0.05 for both）; most patients with URTI were anosmic（χ²=21.568, P<0.001）, and female patients were more than male（χ²=5.898, P<0.05）, elder patients were more than younger（χ²=12.963, P<0.001）; most patients with RSD were anosmic（χ²=12.106, P<0.05）, and male patients were more than female（χ²=4.655, P<0.05）; elder patients were more than younger for idiopathic OD（χ²=5.284, P<0.05）, but no sex difference was found（P>0.05）; patients with congenital anosmia were all lost their smell since they were born, and no sex difference was found in the disease（P>0.05）. Fifty-seven of 146（39%） patients whose gustation was assessed had gustatory dysfunction. Gustatory function was significantly associated with the causes of OD（r=0.368, P<0.05）, but not related to olfactory function, age and sex（P>0.05 for all）. Conclusion:The leading causes of olfactory dysfunction were head trauma, URTI, RSD, and idiopathic causes. Each of OD had its own distinct clinical features. Gustatory dysfunction were common in patients with OD, and gustatory function was related to the causes of OD. High priority should be given to gustatory function evaluation for the patients with OD.

A novel irrigation device with superior nasal irrigation efficiency to the classic rinse bottle.

BACKGROUND: The ability of saline irrigation to detach the mucous and the flow-limiting effect of the nasal valve has not been well explored. The objective of this study was to compare the removal efficiency of a novel irrigation device with an extended nozzle versus a classic rinse bottle. METHODS: Transparent casts of the unoperated sinonasal cavity were made by 3D printing. Yogurt was used to simulate mucous. The cast filled with 5 ml yogurt was fixed in six head positions and irrigated with 120 ml, 175 ml, and 240 ml dyed water through the novel device and the rinse bottle. The irrigation efficiency was the ratio of the weight of yogurt washed away divided by the total weight of yogurt. RESULTS: The irrigation stream of a long nozzle with a side opening was different from the irrigation stream of the outlet within the nasal vestibule. The novel devices presented with continuous water stream directly upwards to the anterior part of the olfactory cleft. Depending on different head positions, it was easy for the novel devices to achieve an irrigation efficiency of 100% when the cast was irrigated with 120 ml or 175 ml water. There was still a tiny amount of yogurt left in the olfactory cleft when the cast was irrigated with 240 ml water under each head position for the rinse bottle. The irrigation efficiency was volume-dependent, and the average irrigation efficiency of the rinse bottle at 240 ml only reached 69.1%. CONCLUSIONS: The novel irrigation device presented with superior nasal irrigation efficiency to the classic rinse bottle. A continuous water stream directly upwards to the anterior part of the olfactory cleft combined with an extended nozzle overcoming the flow-limiting effect of the nasal valve promotes nasal irrigation efficiency.

Development of a novel centrifugal extraction device to collect the olfactory cleft mucus.

BACKGROUND: Measuring olfactory cleft mucus biomarkers provides critical insights into the pathogenesis of the olfactory dysfunction. OBJECTIVES: This study aimed to develop a novel centrifugal extraction device to collect the olfactory cleft mucus. MATERIAL AND METHODS: The olfactory cleft mucus was collected from 18 patients with chronic rhinosinusitis (CRS) and 10 healthy controls using polyvinyl alcohol (PVA) sponges. Both novel centrifugal extraction devices and traditional devices which consisted of a falcon tube and a syringe shaft were utilized. Levels of Galectin-10 were assessed using the enzyme-linked immunosorbent assay. The olfaction was evaluated with Sniffin' Sticks. RESULTS: The average extraction efficiency of recovered volume for novel centrifugal extraction devices and traditional devices was 85.44 and 79.15%, respectively. Galectin-10 levels of the olfactory cleft mucus in patients with CRS were significantly higher than that in controls when extracted through novel devices (p < .001). Furthermore, levels of Galectin-10 in patients with CRS significantly correlated with TDI score (p = .020, r = -0.546). There was no significant difference between novel and traditional devices regarding Galectin-10 levels in CRS (p = .966). CONCLUSIONS AND SIGNIFICANCE: The novel centrifugal extraction device with PVA sponges proved to be a feasible method to collect the olfactory cleft mucus.

Development of an apparatus and procedure for evaluating the efficiency of nasal irrigation.

BACKGROUND: Although different methods of nasal irrigation have been utilized, irrigation efficiency in nasal cavities has not been well assessed. The objective of this study was to develop an apparatus and procedure for evaluating the irrigation efficiency and to explore the optimal head position during irrigation. METHODS: Casts of the left sinonasal cavity from a healthy volunteer were made from high-resolution-computed tomography data using 3D printing with composite materials. An adjustable apparatus that allowed cast fixation at the different head positions was built. The yogurt was used to simulate mucus. The cast with 5 ml yogurt filled around the superior, middle, and inferior turbinate was fixed in six head positions including head tilt 10°, 45°, and 60° forward with or without leaning 30° to the right. The cast was irrigated with 120 ml, 175 ml, and 240 ml dyed water and was video recorded. The irrigation efficiency was calculated based on the weight difference of the cast before and after the irrigation. RESULTS: Most residual yogurt was located around the superior meatus after the irrigation under different volumes and head positions. The irrigation efficiency of the rinse bottle or the pulsatile device was volume dependent, with the highest irrigation efficiency under 240 ml water. When the left sinonasal cavity was irrigated, the head position of tilt 45° forward with leaning 30° to the right was the optimal head position for these two devices when compared to other positions. The pulsatile device with 240 ml water performed better than the rinse bottle with 240 ml water regarding the irrigation efficiency under the optimal head position (0.8700 ± 0.0138 vs 0.7536 ± 0.0099, p = 0.003). CONCLUSIONS: The developed apparatus provided a potential method for evaluating the irrigation efficiency. The head position of tilt 45° forward with leaning 30° was suitable for patients to perform the nasal irrigation.

Clinical significance of the cognition-related pathogenic proteins in plasma neuronal-derived exosomes among normal cognitive adults over 45 years old with olfactory dysfunction.

OBJECTIVES: Exosomal Phospho-Tau-181(P-T181-tau), Total tau (T-tau), and amyloid-ß peptide 42 (Aß42) have been proved the capacity for the amnestic mild cognitive impairment (MCI) and the diagnosis of Alzheimer's disease (AD). This study aimed to explore the cognitive function and the levels of P-T181-tau, T-tau, and Aß42 in neuronal-derived exosomes (NDEs) extracted from plasma in normal cognitive adults over 45 years old with olfactory dysfunction. METHODS: A cross-sectional survey of 29 participants aged over 45 was conducted. Plasma exosomes were isolated, precipitated, and enriched by immuno-absorption with anti- L1 cell adhesion molecule (L1CAM) antibody. NDEs were characterized by CD81, and extracted NDE protein (P-T181-tau, T-tau, and Aß42) biomarkers were quantified by enzyme-linked immunosorbent assay (ELISAs). Olfactory performance was assessed by Sniffin' Sticks and cognitive performance was assessed by Montreal Cognitive Assessment (MoCA). RESULTS: There was no significant difference between adults with olfactory dysfunction and without olfactory dysfunction regarding the cognitive function as measured by MoCA and all the participants showed normal cognition. Adults with olfactory dysfunction showed a higher concentration of P-T181-tau in plasma NDEs than did adults without olfactory dysfunction (P = 0.034). Both the levels of P-T181-tau (r = - 0.553, P = 0.003) and T-tau (r = - 0.417, P = 0.034) negatively correlated with the odor identification scores. In addition, the level of T-tau negatively correlated with MoCA scores (r = - 0.597, P = 0.002). The levels of P-T181-tau (r = - 0.464, P = 0.022) and T-tau (r = - 0.438, P = 0.032) negatively correlated with the delayed recall scores. CONCLUSIONS: This study demonstrated that cognition-related pathogenic proteins including P-T181-tau in plasma NDEs were significantly increased in adults over 45 years old with olfactory dysfunction before the occurrence of cognitive impairment. The impaired odor identification and the delayed recall function were highly associated with the increased levels of P-T181-tau and T-tau in plasma NDEs.

Self-assembly and luminescence of trinuclear lanthanide based supramolecular circular helicates.

A series of trinuclear lanthanide circular helicates [Ln3L3]Cl3 have been synthesized via supramolecular subcomponent self-assembly. Photophysical studies demonstrate that the unique helical bis-tetradentate 1,29-dialdehyde ligand L2- could serve as an effective sensitizer for SmIII, EuIII, NdIII and YbIII ions exhibiting efficient characteristic fluorescence emission because of the shell-type blocking of the ligand, which makes them the first circular helicates exhibiting near-infrared lanthanide fluorescence.

Transmetalation and Demetallization for Open-Oyster-like Non-Ionic Cd(II) Macrocycles.

This work designed a nonionic extended dialdehyde 6,6'-(phenylazanediyl)dipicolinaldehyde (PDPA) for constructing Schiff-base macrocyclic complexes with weaker metal-ligand interactions, so as to solve the long-standing challenges of transmetalation and demetallization in macrocyclic complexes. An enantiomeric pair of open-oyster-like 26-membered [2 + 2] Schiff-base macrocyclic dinuclear Cd(II) complexes (S,S-1a, R,R-1b) could be obtained, having S,S/R,R-1,2-diaminocyclohexane (S,S/R,R-DACH) precursors, while Cu(II) ion template only resulted in a mononuclear Schiff-base Cu(II) acyclic complex (S,S-2) accompanied by the half-oxidation of PDPA instead of expected [2 + 2] Cu(II) macrocyclic complexes. It is suggested that the weak oxidization capability of Cu(II) ion is responsible for the formation of S,S-2 because X-ray photoelectron spectroscopy (XPS) for the solid powder of reaction mixture of direct Cu(II) ion template synthesis implies that both Cu(I) and Cu(II) species are present. In fact, corresponding [2 + 2] dinuclear Cu(II) macrocycles and even metal-free macrocycles unsuitable for direct synthesis can be obtained via Cd(II) → Cu(II) transmetalation and Na2S demetalation verified by ESI-MS and UV-vis spectra. In addition, control experiments indicate that the synthesis of metal-free macrocycles via the direct nontemplate method merely results in the mixture of multiple components of [1 + 1], [2 + 2], and [3 + 3] Schiff-base macrocycles, and they are difficult to isolate.

Construction and Photoluminescent Properties of Schiff-Base Macrocyclic Mono-/Di-/Trinuclear ZnII Complexes with the Common 2-Ethylthiophene Pendant Arm.

A new flexible 2-ethylthiophene pendant-armed dialdehyde (H2tdd) was reacted with 1,3-propanediamine, [( S, S),( R, R),(±)]-1,2-diaminocyclohexane, and 1,2-bis(2-aminoethoxy)ethane, giving birth to 36-membered [2 + 2] Schiff-base macrocyclic trinuclear ZnII complex 1, 18-membered [1 + 1] mononuclear ZnII macrocycles 2-4, chiral/racemic 34-membered [2 + 2] dinuclear ZnII complexes 5-9, and 46-membered [2 + 2] dinuclear ZnII macrocycles 10-12 via ZnII ion template-assisted Schiff-base condensation. It is worth mentioning that the secondary template effects for nitrate and halide counterions have been observed in the 1,3-propanediamine involved imine condensation. In all [2 + 2] ZnII macrocycles, dinuclear complexes 5-9 display a full-folded molecular conformation, while trinuclear complex 1 and dinuclear complexes 10-12 exhibit distinct half-folded structures in the presence or absence of intramolecular π-π stacking interactions between two phenolic rings of the dialdehyde component. Interestingly, a solvent-induced single-crystal-to-single-crystal transformation was first achieved for two types of solvated mononuclear macrocycles 3a and 3b (H2O vs CH3CN) with folded and unfolded ligand conformations. In addition, the photoluminescent properties were studied for this family of Schiff-base macrocyclic ZnII complexes as well as the dialdehyde precursor H2tdd.

Schiff-base macrocyclic ZnII complexes based upon flexible pendant-armed extended dialdehydes.

This Frontier article reviews diverse structures of Schiff-base macrocyclic ZnII complexes derived from a family of flexible pendant-armed extended dialdehydes via a preorganized synthetic strategy and the corresponding structure-determining factors, including primary cationic template effects and secondary complementary template effects. In addition, further post-modification and supramolecular self-assembly of Schiff-base ZnII macrocycles and their possible applications in a variety of areas have been discussed.

Transmetalation for Flexible Pendant-Armed Schiff-Base Macrocyclic Complexes Influenced by Halide Effects.

Three 46-membered [2 + 2] pendant-armed Schiff-base macrocyclic dinuclear CdII and CuII complexes (2a, 2b, and 3b) and one 23-membered [1 + 1] CuII macrocycle 4a were prepared from the template-directed condensation reactions between 1,2-bis(2-aminoethoxy)-ethane and extended Cl-dialdehyde in the presence of CdX2 and CuX2 (X = Cl and Br), in which halide effects play important roles in the organization of final macrocyclic complexes in addition to the dominant influence of metal cations. Transmetalation was intensively studied among these CdII and CuII complexes with large and flexible macrocyclic ligands, including two previously synthesized dinuclear ZnII macrocycles (1a and 1b). Our results indicate that ZnII → CuII and CdII → CuII transmetalation proceeds more quickly than that from CdII to ZnII, and all the processes are found to be irreversible. It is noted that a [2 + 2] heterodinuclear CdIIZnII macrocyclic intermediate could be detected by ESI-MS together with [2 + 2] homodinuclear CdII and ZnII macrocyclic complexes. Furthermore, distinct halide behavior was observed in the in situ CdII → CuII and ZnII → CuII metal-ion exchange. That is to say, [2 + 2] macrocycles (1a and 2a) could be converted to [1 + 1] macrocycles 4a and 4b under the reflux condition in the case of CuCl2, accompanied by the configurational transformation from half-folded dinuclear ZnII and CdII to unfolded CuII macrocyclic skeleton. In contrast, CuBr2 leads to a highly efficient transmetalation to corresponding [2 + 2] dinuclear CuII complex 3b from both 1b and 2b no matter the experimental condition used.

Polar Ketone-Functionalized Metal-Organic Framework Showing a High CO2 Adsorption Performance.

The incorporation of various functionalities into porous metal-organic frameworks (MOFs) represents an efficacious strategy to improving their gas adsorption properties. In this work, a carbonylated tetracarboxylic acid ligand (5,5'-carbonyldiisophthalic acid) was synthesized, and a ketone-functionalized MOF with exposed metal sites based on this ligand was formed successfully. Structural analysis reveals that the new MOF possesses channels decorated by the carbonyl groups and rhombicuboctahedral cages, with open CuII sites pointing toward the cage center. The framework exhibits exceptionally high CO2 (46.7 wt % at 273 K and 1 bar) and H2 (2.8 wt % at 77 K and 1 bar) uptake. Furthermore, it displays high selectivities of CO2 adsorption over N2 and CH4 at 298 K.

Construction of Chiral [4 + 4] and [2 + 2] Schiff-Base Macrocyclic Zinc(II) Complexes Influenced by Counterions and Pendant Arms.

Chiral and racemic 68-membered [4 + 4] tetranuclear and 34-membered [2 + 2] dinuclear Schiff-base macrocyclic zinc(II) complexes 1-10 can be selectively synthesized based on the secondary template effects of counterions and pendant arms, when [(S,S), (R,R), (±)]-1,2-diaminocyclohexane precursors are first used to react with a pair of extended dialdehydes with different pendant arms via zinc(II) ion template-assisted imine condensation.