Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 51
Filter
1.
Chemistry ; : e202401154, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38627216

ABSTRACT

A method was developed to link two or three o-carborane moieties to form a series of carboranyl dithioester bridging ligands via in situ substitution of haloalkanes by tetraphenylphosphonium carboranyldithiocarboxylates. Based on these ligands, direct B-H activation without the assistance of Ag(I) and alkali was successfully achieved with half-sandwich Ir(III) substrate [Cp*IrCl2]2 to yield corresponding bimetallic or trimetallic complexes. Single crystal structure analyses of the B-H activated complexes and corresponding SnCl2-inserted derivatives confirm the selective B(3)-H activation in these complexes.

2.
World J Clin Cases ; 12(11): 1857-1862, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38660559

ABSTRACT

In this editorial, we comment on an article by Ruan et al published in a recent issue of the World Journal of Clinical Case. Pulmonary meningothelial proliferative lesions, including primary pulmonary meningiomas, minute pulmonary meningothelial-like nodules, and metastatic pulmonary meningiomas are rare pulmonary lesions. These lesions are difficult to differentiate from lung cancers based on clinical and imaging manifestations. Herein, we briefly introduce the clinical, imaging, and pathological characteristics of these lesions and discuss their pathogenesis to strengthen the current understanding of pulmonary meningothelial proliferative lesions in clinical diagnosis and therapy.

3.
Angew Chem Int Ed Engl ; : e202405399, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38570193

ABSTRACT

Through a coordination-driven self-assembly method, four 4 1 2 ${4_1^2 }$ metalla-links and one tetranuclear monocycle were constructed with high selectivity and yield by adjusting the substituent species of the building blocks, as evidenced using X-ray crystallographic analysis, electrospray ionization-time-of-flight/mass spectrometry (ESI-TOF/MS), elemental analysis and detailed solution-state nuclear magnetic resonance (NMR) spectroscopy. Based on X-ray crystallographic analysis and independent gradient model analysis, a significant factor leading to the formation of 4 1 2 ${4_1^2 }$ metalla-links was the introduction of F, Cl, Br and I atoms, which generated additional weak C-H⋅⋅⋅X (X=F, Cl, Br and I) interactions. Furthermore, the dynamic conversion of 4 1 2 ${4_1^2 }$ metalla-links to monocyclic rings in methanol solution was systematically investigated using quantitative 1H NMR techniques.

4.
Am J Transl Res ; 16(2): 599-616, 2024.
Article in English | MEDLINE | ID: mdl-38463603

ABSTRACT

OBJECTIVE: This study aimed to analyze the efficacy of acupuncture alone or combined with physical therapy compared to other treatment interventions for relieving pain and improving function in rotator cuff diseases. METHODS: Our study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. After PROSPERO (CRD42023396740) registration, all randomized controlled trials (RCTs) published from the inception of the databases to October 10, 2023, evaluating the efficacy of acupuncture either alone or in combination with physical therapy for treating rotator cuff diseases, were extracted from seven databases, including PubMed, Embase, the Web of Science, the Cochrane Library, the China National Knowledge Infrastructure (CNKI), the VIP Database for Chinese Technical Periodicals (VIP), and the Wanfang Date. Two independent researchers assessed the quality of the included studies and extracted relevant data. Furthermore, a meta-analysis was conducted using Stata 14 software. RESULTS: We included 13 RCTs - 12 published in English and 1 in Chinese - that enrolled 1,371 patients. The meta-analysis results demonstrated that acupuncture alone or in combination with physical therapy was superior to other interventions for short-term shoulder joint function improvement (standardized mean difference [SMD] = -0.82, 95% confidence interval [95% CI]: -1.28 to -0.35, P = 0.001), medium-term shoulder joint function improvement (SMD = -1.00, 95% CI: -1.62 to -0.38, P = 0.002), short-term pain relief (weighted mean difference [WMD] = -1.37, 95% CI: -2.39 to -0.38, P = 0.006), medium-term pain relief (WMD = -1.66, 95% CI: -2.70 to -0.63, P = 0.002), and post-treatment shoulder joint abduction improvements (SMD = 0.68, 95% CI: 0.20 to 1.16, P = 0.005), external rotation (SMD = 0.62, 95% CI: 0.13 to 1.11, P = 0.012), and forward flexion (SMD = 0.71, 95% CI: 0.44 to 0.97, P < 0.001), with significant differences (P < 0.05). CONCLUSION: Based on the current clinical data, meta-analysis showed that acupuncture alone or combined with physical therapy is efficacious for short- and medium-term (< 3 months) pain relief and functional improvements. However, compared to other interventions, the efficacy of the long-term (3 to 12 months) period did not significantly differ. After treatment, these modalities displayed advantages such as improved shoulder joint abduction, external rotation, and forward flexion movements. However, no significant difference was noted in internal rotation movement. Thus, future studies might further investigate whether different acupuncture methods affect the efficacy of treating rotator cuff diseases and improving long-term outcome.

6.
Orthop Surg ; 16(1): 234-244, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38041507

ABSTRACT

OBJECTIVE: Closed reduction combined with external fixation is a frequently utilized approach for treating distal radial fractures in adults. Nonetheless, the potential for re-displacement following external fixation remains. Analyzing the factors influencing re-displacement after nonsurgical treatment of distal radial fractures in adults is vital for preventing re-displacement and making prognostic assessments. METHODS: A retrospective analysis was performed on 884 patients who underwent nonsurgical treatment for distal radius fractures in the reduction room of the Orthopedics and Traumatology Department of Integrated Traditional Chinese and Western Medicine at Tianjin Hospital, Tianjin, China, between July 2019 and December 2022. Patients were categorized into two groups, namely displaced and nondisplaced, based on radiographic outcomes. Factors affecting fracture re-displacement were examined, including sex, age, side, AO/OTA type, external fixation, and radiographic outcomes at pre-reduction and immediate reduction. Logistic regression analysis was employed to identify the risk factors for fracture re-displacement, and ROC curves were constructed. RESULTS: Among the 884 patients, 563 (63.69%) experienced re-displacement after fracture reduction. There were no statistically significant differences (p > 0.05) between the two groups in terms of gender, external fixation method, and palmar tilt angle at pre-reduction and immediate reduction, while significant differences (p < 0.05) were observed in age, side, AO/OTA type, and radial inclination, radial length, and radiographic outcomes of ulnar variance at pre-reduction and immediate reduction. Multifactorial logistic regression analysis revealed that age (odds ratio [OR] = 1.027, p < 0.001), AO/OTA type (OR = 2.327, p = 0.005), ulnar variance at pre-reduction (OR = 1.142, p = 0.048), and ulnar variance at immediate reduction (OR = 1.685, p < 0.001) were significant factors (p < 0.05) associated with re-displacement following nonoperative treatment of adult distal radius fractures. For patients aged ≥60 years, the amount of missing radiographic outcomes was positively correlated with age. The receiver operating characteristic curve demonstrated that age ≥65.5 years, ulnar variance >3.26 mm at pre-reduction, and ulnar variance >2.055 mm at immediate reduction were high-risk factors for fracture re-displacement. CONCLUSIONS: Nonsurgical treatment of distal radius fractures exhibits a higher rate of re-displacement. Age, AO/OTA type, pre-reduction, and immediate reduction ulnar variance are key factors predicting fracture re-displacement.


Subject(s)
Radius Fractures , Wrist Fractures , Adult , Humans , Retrospective Studies , Radius Fractures/therapy , Radius Fractures/surgery , Fracture Fixation/methods , Prognosis , Treatment Outcome , Fracture Fixation, Internal/methods , Bone Plates , Range of Motion, Articular
7.
Medicine (Baltimore) ; 102(50): e36739, 2023 Dec 15.
Article in English | MEDLINE | ID: mdl-38115250

ABSTRACT

RATIONALE: Adenomatoid tumors are rare benign tumors, mainly involving the reproductive tract, such as the epididymis in men and the uterus and fallopian tubes in women. However, a few cases can occur outside the reproductive tract. Herein, we report a rare case of a primary adenomatoid tumor of the adrenal gland. PATIENT CONCERNS: A 50-year-old man underwent ultrasound examination and was found to have a right adrenal mass without elevated blood pressure, weakness after fatigue, frequent nocturnal urination urgency, pain, or a history of hematuria. The patient's general health was normal. Computed tomography revealed a polycystic mixed-density lesion in the right adrenal region, approximately 7.3 × 4.5 cm in size. DIAGNOSES: Based on the clinical information, morphological features, and immunohistochemistry results, a pathological diagnosis of primary adenomatoid tumor of the adrenal gland was made. INTERVENTION: Excision of the right adrenal gland and tumor through the 11 ribs. OUTCOMES: The patient's postoperative course was uneventful. LESSONS: Preventing misdiagnosis adenomatoid tumors with other types of adrenal gland tumors or metastatic tumors is imperative. Morphological and immunohistochemical features can help diagnose primary adenomatoid tumors of the adrenal gland.


Subject(s)
Adenomatoid Tumor , Adrenal Gland Neoplasms , Humans , Male , Middle Aged , Adenomatoid Tumor/diagnosis , Adenomatoid Tumor/surgery , Adrenal Gland Neoplasms/diagnosis , Adrenal Gland Neoplasms/surgery , Adrenal Gland Neoplasms/pathology , Adrenal Glands/diagnostic imaging , Adrenal Glands/surgery , Adrenal Glands/pathology , Immunohistochemistry , Tomography, X-Ray Computed
8.
Angew Chem Int Ed Engl ; 62(46): e202313605, 2023 Nov 13.
Article in English | MEDLINE | ID: mdl-37783666

ABSTRACT

By exploiting coordination-driven self-assembly, high yields of two 818 molecular metalla-knots could be obtained using a thiazole-moiety-containing asymmetric dipyridyl ligand 2-(pyridin-4-yl)-5-(pyridin-4-ylethynyl)benzo[d]thiazole (L1 ), as confirmed using X-ray crystallographic analysis, electrospray ionization-time-of-flight/mass spectrometry (ESI-TOF/MS), and detailed liquid-state nuclear magnetic resonance (NMR) spectroscopy. To modulate the self-assembled structures, m-chloroperbenzoic acid (m-CPBA) was utilized to oxidize thiazole-based ligand L1 to N-thiazole-oxide-based ligand 2-(pyridin-4-yl)-5-(pyridin-4-ylethynyl)benzo[d]thiazole 3-oxide (L2 ), which enabled the selective construction of the corresponding tetranuclear macrocycles. Notably, two molecular metalla-knots could be topologically transformed from 818 knots to simple monocycles because the L1 alkyne bond was inert toward m-CPBA, as confirmed by liquid-state NMR spectroscopy, ESI-TOF/MS, and elemental analysis.

9.
Nanomaterials (Basel) ; 13(12)2023 Jun 19.
Article in English | MEDLINE | ID: mdl-37368315

ABSTRACT

Single-walled carbon nanotube (SWCNT) is a promising candidate for strengthening nanocomposite. As the matrix of nanocomposite, a single crystal of copper is designed to be in-plane auxetic along the crystal orientation [1 1 0]. In that way, the nanocomposite could also be auxetic when enhanced by (7, 2) a single-walled carbon nanotube with relatively small in-plane Poisson's ratio. A series of molecular dynamics (MD) models of the nanocomposite metamaterial are then established to study mechanical behaviors of the nanocomposite. In the modelling, the gap between copper and SWCNT is determined following the principle of crystal stability. The enhanced effect for different content and temperature in different directions is discussed in detail. This study provides a complete set of mechanical parameters of nanocomposite including thermal expansion coefficients (TECs) from 300 K to 800 K for five weight fractions, which is essential for a wide range of applications of auxetic nanocomposites in the future.

10.
Chemistry ; 29(30): e202204038, 2023 May 26.
Article in English | MEDLINE | ID: mdl-36896562

ABSTRACT

A series of Cp* Rh-based discrete architectures was constructed by selecting four ether bipyridyl ligands and three half-sandwich rhodium(III) bimetallic construction units, respectively. This study demonstrates a strategy for making the transition from a binuclear D-shaped ring to a tetranuclear [2]catenane by adjusting the length of bipyridyl ligands. In addition, changing the position on the naphthyl group of the bipyridyl ligand from 2,6- to 1,5-position substitution can realize the selective synthesis of [2]catenane and Borromean rings under similar conditions. The above-mentioned constructions have been determined via X-ray crystallographic analysis, detailed NMR techniques, electrospray ionization-time-of-flight/mass spectrometry analysis, and elemental analysis.

11.
Medicine (Baltimore) ; 102(6): e32871, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36820581

ABSTRACT

RATIONALE: Salivary gland-type acinic cell carcinoma (ACC) is a low-grade malignancy. Primary ACC of the trachea and lungs is rare; here, we describe 1 such case. The histological morphology of tracheal ACC was similar to that of its salivary gland-associated equivalent. Because of its rarity, it is easily misdiagnosed as another type of tracheal or lung tumor. Microscopic analysis of pathological features and immunohistochemistry help diagnose primary ACC of the trachea and lungs. PATIENT CONCERNS: A 33-year-old female complained of shortness of breath and hemoptysis for 2 years, and reported the symptoms to have aggravated over the last 4 months. The patient was admitted to our hospital for further treatment. Enhanced computed tomography revealed a soft tissue density nodule shadow in the trachea, which was approximately 1.3 × 1.2 cm in size. DIAGNOSES: Based on the clinical information, morphological features, and immunohistochemistry, the pathological diagnosis was primary ACC of the trachea. INTERVENTION: The tracheal lesion was resected with an electric snare, electrotomy, freezing, and an argon knife using a rigid bronchoscope. OUTCOMES: The patient's postoperative course was uneventful. LESSONS: It is important to prevent misdiagnosis of this type of tumor as another type of lung tumor. Morphological and immunohistochemical features can be useful in diagnosing primary ACC of the trachea and lungs.


Subject(s)
Carcinoma, Acinar Cell , Lung Neoplasms , Tracheal Neoplasms , Female , Humans , Adult , Trachea/surgery , Tracheal Neoplasms/diagnosis , Tracheal Neoplasms/surgery , Tracheal Neoplasms/pathology , Carcinoma, Acinar Cell/diagnosis , Carcinoma, Acinar Cell/surgery , Carcinoma, Acinar Cell/pathology , Lung Neoplasms/pathology , Lung/pathology
12.
World J Clin Cases ; 11(1): 164-171, 2023 Jan 06.
Article in English | MEDLINE | ID: mdl-36687181

ABSTRACT

BACKGROUND: Thymic lipofibroadenomas are extremely rare. In this study, we investigated the clinicopathological characteristics of thymic lipofibroadenomas. CASE SUMMARY: This study included three patients with thymic lipofibroadenomas. We retrospectively analyzed the patient data to determine the clinicopathological characteristics of thymic lipofibroadenomas. The study included one man and two women [mean age, 43 (33-59) years]. All patients were non-smokers and presented with well-defined anterior mediastinal tumors. The cut surfaces of the tumors were solid, with a mixture of yellow and white areas. Microscopic evaluation of resected specimens showed scattered cord-like structures of epithelial cells embedded within abundant fibrotic and hyaline stroma admixed with variable quantities of adipose tissue. One patient showed hyperplastic thymic tissue in a part of the tumor. CONCLUSION: Thymic lipofibroadenomas are an extremely rare type of benign thymic tumor. Surgical removal of lipofibroadenomas is usually curative.

13.
J Am Chem Soc ; 145(8): 4746-4756, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36716227

ABSTRACT

Facilitated by multiple stacking interactions between components, two kinds of metalla-links containing molecular Borromean rings (623 links) and head-to-tail cyclic [3]catenanes (613 links), as isomers, were constructed in high yield by introducing tri-µ-methoxyl-dinuclear complexes [(Cp*M)2(µ-OCH3)3][OTf] (M = RhIII or IrIII, Cp* = η5-pentamethylcyclopentadienyl, OTf = triflate) as unusual cationic guests during coordination-driven assembly. The topology of these intricate structures was controlled by strategically selecting two dipyridyl ligands that differ in their coordination orientations, as evidenced by X-ray crystallography and electrospray ionization-time-of-flight/mass spectrometry analysis. The behavior of the abovementioned metalla-links in solution was monitored and further studied by the detailed NMR techniques.

14.
Materials (Basel) ; 15(24)2022 Dec 07.
Article in English | MEDLINE | ID: mdl-36556525

ABSTRACT

Single-walled carbon nanotubes (SWCNTs) have superior mechanical properties which originate from a strong C-C covalent bond and unique nanostructure. Chirality, one of the helical structural parameters of SWCNTs, leads to differences in mechanical performance. In this work, molecular dynamics (MD) simulation was performed to analyze engineering Poisson's ratio (EPR) and incremental Poisson's ratio (IPR) of SWCNTs with different chiral angles, respectively, under tensile and compressive load, as well as the chiral effect on rigidity. We reported the minimum EPR for (4, 1) SWCNT and obtained the distribution and trend of EPR which is dependent on chiral index m. In addition, a new observation showed two exactly opposite trends of EPR existing not only in tension and compression but also in the longitudinal and radial directions. Furthermore, we found that the critical strain, over which SWCNT would be auxetic, ranged from 6% to 18% and was also chirality-dependent. Three representative SWCNTs with chiral angle of 0° (zigzag), 10.89° (chiral), and 30° (armchair) were selected for the mechanism study of auxeticity. Finally, a method of the contribution to radial strain for two main deformation modes proposed in this paper could well explain the negative IPR phenomenon.

15.
J Affect Disord ; 314: 160-167, 2022 10 01.
Article in English | MEDLINE | ID: mdl-35863541

ABSTRACT

BACKGROUND: Dementia and cognitive impairment can be attributed to genetic and modifiable factors. Considerable evidence emerged in modifiable factors and urgently requires standardized evaluation. We conducted an umbrella review to evaluate the strength and validity of the existing evidence. METHODS: We searched PubMed, Embase, CINAHL and Cochrane Database of Systematic Reviews to identify relevant systematic reviews and meta-analyses of prospective studies regarding the associations of dementia and cognitive impairment with modifiable factors. For each association, we analyzed the summary effect size, 95 % confidence interval, 95 % prediction interval, heterogeneity, small study effect and excess significance bias. Mendelian randomization studies were descriptively reviewed further exploring the causality of the associations. RESULTS: In total, 12,015 articles were identified, of which 118 eligible studies yielded 243 unique associations. Convincing evidence was found for associations of dementia and cognitive impairment with early-life education, midlife to late-life plasma glucose, BMI, atrial fibrillation, benzodiazepine use, and gait speed. Suggestive to highly suggestive evidence was found for that of midlife to late-life blood pressure, homocysteine, cerebrovascular diseases, hearing impairment, respiratory illness, anemia, smoking, alcohol consumption, diet, sleep, physical activity and social engagement. Among convincing evidence, Mendelian randomization studies verified causal relationships of education and plasma glucose with Alzheimer's disease. LIMITATIONS: Low quality of the studies included. CONCLUSIONS: Modifiable risk factors identified in this study, especially those with high-level evidence, should be considered in dementia prevention. Our results support a valuable rationale for future experimental designs to establish further evidence for the associations in larger populations.


Subject(s)
Alzheimer Disease , Cognitive Dysfunction , Alzheimer Disease/epidemiology , Alzheimer Disease/etiology , Blood Glucose , Cognitive Dysfunction/epidemiology , Humans , Prospective Studies , Risk Factors , Systematic Reviews as Topic
16.
Medicine (Baltimore) ; 101(18): e29224, 2022 May 06.
Article in English | MEDLINE | ID: mdl-35550474

ABSTRACT

RATIONALE: Polymorphous low-grade adenocarcinoma is a low-risk infiltrative malignant tumor of the salivary glands. However, some of these tumors are more malignant than the low-grade tumors and therefore, according to the most recent recommendation of the World Health Organization, they are renamed as polymorphous adenocarcinomas (PACs). Primary polymorphous low-grade adenocarcinomas/PACs of the lungs are rare. Herein, we report a case of primary PAC of the lung with bronchial cartilage and perineural invasion, and lymph node metastasis. PATIENT CONCERNS: A 58-year-old man had developed fever half a month prior, without chills or other accompanying symptoms, and the underlying reasons were unknown. His self-measured temperature was up to 39°C, accompanied by cough and expectoration, yellow and thin sputum, and shortness of breath. The patient's general state was normal, and respiratory sounds originating from the right lung were weak. Enhancement computed tomography revealed that the bronchial lumen of the basal segment of the lower lobe of the right lung was narrow; soft tissue density nodules were seen, with a range of approximately 2.4 cm × 1.3 cm. DIAGNOSIS: Based on clinical information, morphological features, and immunohistochemistry results, the pathological diagnosis was primary PAC of the lungs. INTERVENTION: Thoracoscopic resection of the middle and lower lobes of the right lung was performed, further extended dissection of the mediastinal lymph nodes was performed. OUTCOMES: The postoperative course was uneventful. LESSONS: Primary PAC of the lung is rare and may cause misdiagnosis. When encountering a lung tumor with diverse tissue structures, uniform cell type and nerve invasion, we should consider the possibility of PAC. Morphological and immunohistochemical features can be useful for diagnosing primary PAC of the lungs.


Subject(s)
Adenocarcinoma , Salivary Gland Neoplasms , Adenocarcinoma/diagnosis , Adenocarcinoma/metabolism , Adenocarcinoma/surgery , Bronchi/pathology , Humans , Immunohistochemistry , Male , Middle Aged , Salivary Gland Neoplasms/pathology , Salivary Glands/pathology
17.
BMC Musculoskelet Disord ; 22(1): 580, 2021 Jun 24.
Article in English | MEDLINE | ID: mdl-34167511

ABSTRACT

BACKGROUND: Revisions are mainly caused by wear debris-induced aseptic loosening. How to effectively suppress debris-induced periprosthetic osteolysis has become an urgent problem. Both zoledronic acid and teriparatide can increase the bone mass around prostheses and increase the stability of prostheses. A hypothesis was proposed: the combination of the two drugs may have a better treatment effect than the use of either drug alone. METHODS: We created a rabbit model to study the effect and mechanism of the combination of zoledronic acid and teriparatide in the treatment of aseptic loosening. Thirty-two adult male New Zealand white rabbits were selected and treated with TKA surgery, and a titanium rod prosthesis coated evenly with micrometre-sized titanium debris was implanted into the right femoral medullary cavity. All rabbits were randomized into four groups (control group = 8, zoledronic acid group = 8, teriparatide group = 8, and zoledronic acid + teriparatide group = 8). All the animals were sacrificed in the 12th week, and X-ray analyses, H&E staining, Goldner-Masson trichrome staining, von Kossa staining, and RT-PCR and Western blotting of the mRNA and protein of OCN, OPG, RANKL and TRAP5b in the interface membrane tissues around the prostheses were immediately carried out. RESULTS: The results shown that both zoledronic acid and teriparatide could inhibit debris-induced peri-prosthetic osteolysis and promote new bone formation. Zoledronic acid was more capable of inhibiting osteoclast activation and peri-prosthetic osteolysis, while teriparatide was more capable of promoting osteoblast function and peri-prosthetic bone integration. CONCLUSION: This research confirmed that the combination of zoledronic acid and teriparatide could prevent and treat aseptic loosening of the prosthesis more effectively. However, the safety of this combination and the feasibility of long-term application have not been ensured, and the clinical application requires further experiments and clinical research support.


Subject(s)
Osteolysis , Teriparatide , Animals , Male , Osteoclasts , Osteolysis/drug therapy , Osteolysis/etiology , Osteolysis/prevention & control , Prosthesis Failure , Rabbits , Titanium , Zoledronic Acid
18.
Chem Asian J ; 16(14): 1918-1924, 2021 Jul 19.
Article in English | MEDLINE | ID: mdl-33960138

ABSTRACT

Two Cp*-RhIII based trefoil knots were obtained in high yield under ambient conditions via the coordination-driven self-assembly of semi-rigid thioether dipyridyl ligand 1,4-bis[(pyridin-4-ylthio)methyl]benzene (L1 ), ligand chloranilic acid (H2 -CA) and 6,11-dihydroxytetracene-5,12-dione (H2 -TtDo) with Cp*RhIII metal corner units, respectively. Furthermore, using the bulkier 4,4'-{[(2,5-dimethyl-1,4-phenylene)bis(methylene)]bis(sulfanediyl)}dipyridine (L2 ) in the place of ligand L1 in the construction process resulted in the formation of a teranuclear metallacycle and a template-free Borromean ring in high yields thanks to significantly altered intermolecular forces between the constituent ligands induced by the sterically-hindering methyl groups of L2 , as demonstrated via a detailed X-ray crystallographic analysis and NMR spectroscopy.

19.
Angew Chem Int Ed Engl ; 60(28): 15466-15471, 2021 Jul 05.
Article in English | MEDLINE | ID: mdl-33871131

ABSTRACT

A Cp*-Rh based D-shaped binuclear metallacycle and a template-free molecular Borromean ring (BR) were obtained in high yield using the semi-rigid thioether dipyridyl ligand 1,4-bis[(pyridin-4-ylthio)methyl]benzene (Bptmb). The topological transformation from a binuclear metallacycle and a BR to tetranuclear metallacycles was realized via the controlled oxidation of thioethers. The strategy used in this work can be regarded as a new form of stimuli-responsive post-synthesis modification (PSM).

20.
J Am Chem Soc ; 143(2): 1119-1125, 2021 01 20.
Article in English | MEDLINE | ID: mdl-33382617

ABSTRACT

Two molecular metalla-knots containing over 500 non-hydrogen atoms (especially 16 RhIII ions) and one molecular Borromean ring were obtained in high yields facilitated by multiple intermolecular interactions between their components. The syntheses rely on the strategic selection of the nonlinear dipyridyl ligand 2,7-di(pyridin-4-yl)-9H-fluorene (L1) as precursor, and the structures of the assemblies were confirmed by detailed X-ray crystallographic analysis. Subsequently, replacing L1 with the bulkier ligand 4,4'-(9,9-dimethyl-9H-fluorene-2,7-diyl)dipyridine (L2) led to the formation of three tetranuclear metallocycles in high yields on account of the weakened π-π stacking interactions between the naphthacene/anthracene and fluorene moieties, which in turn confirmed the significance of stacking interactions in the construction of the molecular 818 metalla-knots and the molecular Borromean ring.

SELECTION OF CITATIONS
SEARCH DETAIL
...