Study on the mechanism and response law of fracture movement on the super-high position hard-thick strata.

In this paper, a thick plate structural mechanical model was established for the hard-thick rock strata in the Ordos region, which was characterized by the occurrence of high-energy strong earthquakes caused by the fracture of hard-thick rock strata. Subsequently, based on Vlasov's theory, the evolution process of hard-thick rock strata was analyzed. And the paper validated the analysis results using high-energy mine earthquake and surface subsidence data. The following conclusions were drawn: (1) The hard-thick strata in the cretaceous system will not be broken during the advancing and mining process of the test panel of the Shilawusu coal mine. (2) When the test panel is mined to a distance of two panel widths, no fracture occurred in the lower part of the hard-thick strata, because no separated space was formed. (3) When the test panel was advanced to about 856 m, the hard-thick strata have fractured in a vertical direction. (4) No high-energy mine earthquake event has occurred during mining at test panel, and the amount of surface subsidence is approximately 200 mm. (5) In the mining at test panel, two high-energy mining earthquakes occurred at 837 m, 1153 m away from the initial position of the panel, respectively, and the maximum amount of surface subsidence increased to 1397 mm, which accords with the results of the first and periodic breaks calculated by theory. The research results of this paper are of guiding significance for the study of the breaking law of hard-thick strata under similar engineering geological conditions and disaster pre-control.

Impact of Regional Anesthesia on Subjective Quality of Recovery in Patients Undergoing Thoracic Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVES: Regional anesthesia can be effective for managing pain after thoracic surgery. This study evaluated whether it can also improve patient-reported quality of recovery (QoR) after such surgery. DESIGN: Meta-analysis of randomized controlled trials. SETTING: Postoperative care. INTERVENTION: Perioperative regional anesthesia. PATIENTS: Adults undergoing thoracic surgery. MEASUREMENTS AND MAIN RESULTS: The primary outcome was total QoR scores 24 hours after surgery. Secondary outcomes were postoperative opioid consumption, pain scores, pulmonary function, respiratory complications, and other adverse effects. Eight studies were identified, of which 6 involving 532 patients receiving video-assisted thoracic surgery were included in the quantitative analysis of QoR. Regional anesthesia significantly improved QoR-40 score (mean difference 9.48; 95% CI 3.53-15.44; I2 = 89%; 4 trials involving 296 patients) and QoR-15 score (mean difference 6.7; 95% CI 2.58-10.82; I2 = 0%; 2 trials involving 236 patients). Regional anesthesia also significantly reduced postoperative opioid consumption and the incidence of nausea and vomiting. Insufficient data were available to meta-analyze the effects of regional anesthesia on postoperative pulmonary function or respiratory complications. CONCLUSIONS: The available evidence suggests that regional anesthesia can enhance QoR after video-assisted thoracic surgery. Future studies should confirm and extend these findings.

Inflation using hydrogen improves donor lung quality by regulating mitochondrial function during cold ischemia phase.

BACKGROUND: Mitochondrial dysfunction results in poor organ quality, negatively affecting the outcomes of lung transplantation. Whether hydrogen benefits mitochondrial function in cold-preserved donors remain unclear. The present study assessed the effect of hydrogen on mitochondrial dysfunction in donor lung injury during cold ischemia phase (CIP) and explored the underlying regulatory mechanism. METHODS: Left donor lungs were inflated using 40% oxygen + 60% nitrogen (O group), or 3% hydrogen + 40% oxygen + 57% nitrogen (H group). Donor lungs were deflated in the control group and were harvested immediately after perfusion in the sham group (n = 10). Inflammation, oxidative stress, apoptosis, histological changes, mitochondrial energy metabolism, and mitochondrial structure and function were assessed. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were also analyzed. RESULTS: Compared with the sham group, inflammatory response, oxidative stress, histopathological changes, and mitochondrial damage were severe in the other three groups. However, these injury indexes were remarkably decreased in O and H groups, with increased Nrf2 and HO-1 levels, elevated mitochondrial biosynthesis, inhibition of anaerobic glycolysis and restored mitochondrial structure and function compared with the control group. Moreover, inflation using hydrogen contributed to stronger protection against mitochondrial dysfunction and higher levels of Nrf2 and HO-1 when comparing with O group. CONCLUSIONS: Lung inflation using hydrogen during CIP may improve donor lung quality by mitigating mitochondrial structural anomalies, enhancing mitochondrial function, and alleviating oxidative stress, inflammation, and apoptosis, which may be achieved through activation of the Nrf2/HO-1 pathway.

Neural and molecular investigation into the paraventricular thalamic-nucleus accumbens circuit for pain sensation and non-opioid analgesia.

The paucity of medications with novel mechanisms for pain treatment combined with the severe adverse effects of opioid analgesics has led to an imperative pursuit of non-opioid analgesia and a better understanding of pain mechanisms. Here, we identify the putative glutamatergic inputs from the paraventricular thalamic nucleus to the nucleus accumbens (PVTGlut→NAc) as a novel neural circuit for pain sensation and non-opioid analgesia. Our in vivo fiber photometry and in vitro electrophysiology experiments found that PVTGlut→NAc neuronal activity increased in response to acute thermal/mechanical stimuli and persistent inflammatory pain. Direct optogenetic activation of these neurons in the PVT or their terminals in the NAc induced pain-like behaviors. Conversely, inhibition of PVTGlut→NAc neurons or their NAc terminals exhibited a potent analgesic effect in both naïve and pathological pain mice, which could not be prevented by pretreatment of naloxone, an opioid receptor antagonist. Anterograde trans-synaptic optogenetic experiments consistently demonstrated that the PVTGlut→NAc circuit bi-directionally modulates pain behaviors. Furthermore, circuit-specific molecular profiling and pharmacological studies revealed dopamine receptor 3 as a candidate target for pain modulation and non-opioid analgesic development. Taken together, these findings provide a previously unknown neural circuit for pain sensation and non-opioid analgesia and a valuable molecular target for developing future safer medication.

Comparison of two methods for extracting exosomes from the nucleus accumbens in mice.

BACKGROUND: Exosomes bind to and are endocytosed by neurons of various brain regions. Methods for isolating and extracting exosomes from specific brain samples are critical. At present, the most important extractive methods for exosomes are Ultracentrifugation and exosome isolation kit extraction. Both of these extraction methods have applications in neuroscience. We compare these methods to reveal the differences. METHODS: We sectioned the nucleus accumbens of mice, and isolated exosomes. A culture medium containing exosomes was extracted using ultracentrifugation (UC) and a total exosome isolation kit (TEI). The exosomes were examined using transmission electron microscopy (TEM), measurement regarding the diameter of the exosomes was done, and the thermal allodynia and western blotting analysis were also conducted, respectively. RESULTS: Transmission electron microscopy observations showed that the ultracentrifugation samples had higher purity and fewer impurities than the kit samples. The results from the two methods were then compared with a number ratio regarding the percentage was not statistically significant. Marker protein tests showed that proteins were expressed under both methods. The thermal allodynia testing observed that the two extraction methods did not affect pain behavior regarding the detection. After the kit extraction method, there were substantial white subjects suspended by PBS. CONCLUSION: Our study compared the different protocols regarding exosome extraction from the nucleus accumbens and compared the quality of two principal methods for exosome extraction from a culture medium containing exosomes. It was found that the extraction quality of exosomes by ultracentrifugation was better, but the technical difficulty was greater.

Packaging Big Data Visualization Based on Computational Intelligence Information Design.

A method based on a computational intelligence information model is proposed to study the visualization of large data packages. Since the CAIM algorithm only considers the distribution of the largest number of classes in an interval, it offers an optimization method and simultaneously determines the appropriate stopping conditions to avoid overcrowding. The effectiveness of the improved algorithm has been experimentally proven. Methods of character reduction and weight determination are used to reduce the index and weight, establishing a large packaging information system. Experimental results show that the improved algorithm in this article produces more classification rules than the CAIM algorithm, because the discrete intervals created by the CAIM algorithm are relatively simple, but the classification rules are few, but less than the number of CAIM algorithms. Classification rules are generated by entropy-based sampling algorithms. This can make the classification rules simple and universal, and it is clear that the optimal sampling algorithm is more accurate than the CAIM algorithm.

Comparison of erector spinae plane and paravertebral nerve blocks for postoperative analgesia in children after the Nuss procedure: study protocol for a randomized controlled non-inferiority clinical trial.

BACKGROUND: Thoracic paravertebral block (TPVB) is a widely advocated regional technique for alleviating postoperative pain in children undergoing elective pectus excavatum repair. However, this technique is associated with some undesirable adverse events. Recently, the erector spinae plane block (ESPB) has been introduced as a practical alternative to the TPVB in thoracic surgery. This interfascial regional anesthesia technique interrupts pain sensation by injecting local anesthetics between the muscular layers of the thoracic wall. Several case series described it as an effective pain management technique following pectus excavatum repair. Therefore, this trial is designed to test the hypothesis that ESPB is non-inferior to TPVB in postoperative pain control after pectus excavatum repair. METHODS: This is a prospective randomized double-blind non-inferiority trial. A total of 40 patients aged 4 to 18 years undergoing Nuss surgery will be randomly assigned to receive pain treatment with either ESPB or TPVB. All patients will receive additional systemic multimodal analgesia with an intravenous patient-controlled analgesia pump and acetaminophen. The primary outcome is the pain intensity at rest, 24 h postoperatively. Secondary outcomes include accumulated morphine-equivalent consumption, postoperative pain scores, emergence agitation incidence, time of the first mobilization, time to first rescue analgesia, complications related to pain treatment, and morphine-related adverse events. DISCUSSION: This will the first randomized controlled trial to compare ESPB with TPVB for analgesia after pectus excavatum repair. This trial aims to provide important clinical evidence to elaborate on the analgesic mechanism of ESPB in children. TRIAL REGISTRATION: ClinicalTrials.gov NCT05034601 . This trial was prospectively registered.

Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading.

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

Behaviors Related to Psychiatric Disorders and Pain Perception in C57BL/6J Mice During Different Phases of Estrous Cycle.

Robust sex difference among humans regarding psychiatry- and pain-related behaviors is being researched; however, the use of female mice in preclinical research is relatively rare due to an unchecked potential behavioral variation over the estrous cycle. In the present study, a battery of psychiatry- and pain-related behaviors are examined under physiological condition in female C57BL/6J mice over different estrous cycle phases: proestrus, estrous, metestrous, diestrous. Our behavioral results reveal that there is no significant difference over different phases of the estrous cycle in social interaction test, sucrose preference test, tail suspension test, open field test, marble burying test, novelty-suppressed feeding test, Hargreaves thermal pain test, and Von Frey mechanical pain test. These findings implicate those psychiatry- and pain-related behaviors in normal female C57BL/6J mice appear to be relatively consistent throughout the estrous cycle; the estrous cycle might not be a main contributor to female C57BL/6J mice's variability of behaviors.

[Anatomy and clinical application of anterior and posterior terminal perforators of peroneal artery].

OBJECTIVE: To investigate the anatomy of anterior and posterior terminal perforators of the peroneal artery and its clinical applications. METHODS: Six lower limb specimens were obtained from 3 fresh cadavers. The anterior and posterior terminal perforators and the perforator of terminal peroneal artery were exposed under surgical microscope, and the distances from the beginning of each perforator branch to the lateral malleolus tip and the external diameter of each perforator were measured. With these anatomical knowledge and contrast-enhanced ultrasound (CEUS) guidance, the pedicle flaps with above-mentioned perforators were rationally selected and precisely designed for 18 patients with skin defects in the ankle and foot region between October 2016 and December 2018. Among the patients, there were 14 males and 4 females, aged 28-62 years, with an average age of 40 years. The area of wound ranged from 4 cm×3 cm to 13 cm×10 cm and the area of skin flap ranged from 5 cm×4 cm to 14 cm×10 cm. The anterior peroneal artery terminal perforator flap were applied in 13 cases and the posterior peroneal artery terminal perforator flap in 5 cases. The donor sites were closed directly in 7 cases and repaired with full thickness skin graft in 11 cases. RESULTS: The distance from the beginning of the anterior terminal perforator to the lateral malleolus tip was (5.1±0.5) cm, the external diameter of the anterior terminal perforator was (1.51±0.05) mm. The distance from the beginning of the posterior terminal perforator to the lateral malleolus tip was (4.9±0.9) cm, the external diameter was (1.78±0.17) mm; the distance from the beginning of the perforator of terminal peroneal artery to the lateral malleolus tip was (1.7±0.7) cm, the external diameter was (0.58±0.12) mm. Clinical application results: The edge of the flap was dark in 2 cases after operation and healed after surgical dressing, and 1 case of wound infection healed gradually after debridement. The other flaps survived and healed by first intention. Three patients underwent plastic surgery at 3 months after operation due to flap swelling. All patients were followed up 3-18 months. During the follow-up period, the flaps had good texture and appearance, and partial recovery of sensation. All cases were assessed by the American Orthopaedic Foot and Ankle Society (AOFAS) score at last follow-up. The results were excellent in 9 cases, good in 6 cases, fair in 2 cases, and poor in 1 case, with the excellent and good rate of 83.3%. CONCLUSION: Further classification of peroneal artery perforators in the lateral malleolus region can improve clinical understanding and be helpful to selection and application of perforator flaps in the lateral malleolus.

[Significance of neutrophil extracellular trap and its markers in the early diagnosis of community-acquired pneumonia in children].

OBJECTIVE: To study the significance of plasma neutrophil extracellular trap (NET) and its markers in the diagnosis of community-acquired pneumonia (CAP) in children. METHODS: A total of 160 children with CAP were enrolled as the CAP group, and 50 healthy children were enrolled the control group. According to disease severity, the CAP group was further divided into a mild CAP subgroup with 137 children and a severe CAP subgroup with 23 children. According to the pathogen, the CAP group was further divided into a bacterial pneumonia subgroup with 78 children, a Mycoplasma pneumonia subgroup with 35 children, and a viral pneumonia subgroup with 47 children. The levels of plasma NET and its markers [antibacterial peptide (LL-37), extracellular free DNA (cfDNA), and deoxyribonuclease I (DNase I)] were measured. Receiver operating characteristic (ROC) curve was used to analyze the value of each index in diagnosing CAP and assessing its severity. RESULTS: Compared with the control group, the CAP group had significant increases in the levels of NET, LL-37, and cfDNA and a significant reduction in the activity of DNase I (P<0.05). Compared with the mild CAP subgroup, the severe CAP subgroup had significantly higher levels of NET, LL-37 and cfDNA and a significantly lower activity of DNase I (P<0.05). There were no significant differences in the levels of NET, LL-37, and cfDNA and the activity of DNase I among the bacterial pneumonia, Mycoplasma pneumonia, and viral pneumonia subgroups (P>0.05). In the CAP group, plasma NET levels were positively correlated with white blood cell count (WBC), percentage of neutrophils, and serum levels of C-reactive protein (CRP), procalcitonin and tumor necrosis factor-α (r=0.166, 0.168, 0.275, 0.181 and 0.173 respectively, P<0.05); LL-37 and cfDNA levels were positively correlated with WBC (r=0.186 and 0.338 respectively, P<0.05) and CRP levels (r=0.309 and 0.274 respectively, P<0.05); the activity of DNase I was negatively correlated with CRP levels (r=-0.482, P<0.05). The ROC curve analysis showed that NET, LL-37, cfDNA, and DNase I had an area under the ROC curve (AUC) of 0.844, 0.648, 0.727, and 0.913 respectively in the diagnosis of CAP, with optimal cut-off values of 182.89, 46.26 ng/mL, 233.13 ng/mL, and 0.39 U/mL respectively, sensitivities of 88.12%, 35.63%, 54.37%, and 91.25% respectively, and specificities of 74.00%, 92.00%, 86.00%, and 76.00% respectively. In the assessment of the severity of CAP, NET, LL-37, cfDNA, and DNase I had an AUC of 0.873, 0.924, 0.820, and 0.778 respectively, with optimal cut-off values of 257.7, 49.11 ng/mL, 252.54 ng/mL, and 0.29 U/mL respectively, sensitivities of 83.21%, 86.96%, 78.26%, and 95.65% respectively, and specificities of 78.26%, 83.94%, 76.64%, and 56.93% respectively. CONCLUSIONS: Plasma NET and its related markers have a certain value in diagnosing CAP and assessing its severity in children.

[Value of simultaneous amplification and testing in early diagnosis of Mycoplasma pneumoniae pneumonia and related influencing factors].

OBJECTIVE: To investigate the value of simultaneous amplification and testing (SAT) in the early diagnosis of Mycoplasma pneumoniae pneumonia (MPP) in children and related influencing factors. METHODS: A total of 526 children with community-acquired pneumonia who were hospitalized between December 2016 and December 2017 were enrolled. Particle agglutination was used to measure serum Mycoplasma pneumoniae (MP) antibody (MP-Ab). The value of SAT in the diagnosis of MPP was evaluated based on these results. RESULTS: Based on the results of serum MP-Ab measurement, 165 children were diagnosed with MPP. MP-SAT had a sensitivity of 90.9% (150/165), a specificity of 97.9% (368/376), and high accuracy (Youden index=0.89) in the diagnosis of MPP, suggesting that there was good consistency between these two methods (Kappa=0.90). The diagnostic sensitivity of MP-SAT in children with a short course of disease was significantly higher than that in children with a long course of disease (P=0.031). The diagnostic sensitivity of MP-SAT was significantly higher than that of single serum MP-Ab measurement (P=0.018), with poor consistency between these two methods (Kappa=0.039). MP-SAT had good consistency with double serum MP-Ab measurement (Kappa=0.91). The multivariate logistic regression analysis showed that course of disease (≥7 days) and out-of-hospital macrolide treatment were the main factors influencing the results of MP-SAT (P<0.05). CONCLUSIONS: MP-SAT has high value in the early diagnosis of MPP and can effectively cover the shortage of single serum MP-Ab test in the acute stage and thus provide help for early clinical diagnosis. MP-SAT test should be performed in the early stage of the disease (<7 days) and before the application of macrolide treatment.

The Anti-inflammatory Effect of Hydrogen on Lung Transplantation Model of Pulmonary Microvascular Endothelial Cells During Cold Storage Period.

BACKGROUND: Lung ischemia-reperfusion injury (LIRI) remains an important factor for the early mortality of lung transplantations. Hydrogen (H2) can attenuate lung injury and improve lung function in animal experiments. In previous studies, pulmonary microvascular endothelial cells (PMVECs) were used to simulate LIRI. We hypothesized that H2 can alleviate inflammatory injury in a PMVECs lung transplantation model in the cold ischemia phase. METHODS: Pulmonary microvascular endothelial cells were divided into 4 groups: blank, control, oxygen (O2), and H2. The blank group included PMVECs without treatment. During the cold storage period, the O2 group was aerated with 40% O2 and 60% N2, and the H2 group was aerated with 3% H2, 40% O2, and 57% N2. The control group was aerated without gases. The mixed gases were replaced every 20 minutes for 4 hours. During the transplantation period, the sealed containers were warmed for 1 hour at room temperature. In the reperfusion period, the containers were aerated with 50% O2, 5% CO2 and 45% N2 at 37°C. RESULTS: The concentrations of interleukin-6 and tumor necrosis factor-α in the extracellular solutions were significantly decreased, and the concentration of interleukin-10 was increased in the H2 group. Intercellular adhesion molecule-1 expression was inhibited by H2. Furthermore, H2 decreased the activation of NF-κB and phosphorylation level of p38. Cell apoptosis was alleviated. The pathological changes in the cell and mitochondria were alleviated after H2 administration. CONCLUSIONS: Hydrogen-attenuated inflammatory response in a PMVECs lung transplantation model during cold storage. The effect may be achieved by inhibition of p38 MAPK and NF-κB pathways.

Di and trinuclear rare-earth metal complexes supported by 3-amido appended indolyl ligands: synthesis, characterization and catalytic activity towards isoprene 1,4-cis polymerization.

Different di and trinuclear rare-earth metal complexes supported by 3-amido appended indolyl ligands were synthesized and their catalytic activities towards isoprene polymerization were investigated. Treatment of [RE(CH2SiMe3)3(thf)2] with 1 equiv. of 3-(CyN[double bond, length as m-dash]CH)C8H5NH in toluene or in THF afforded dinuclear rare-earth metal alkyl complexes having indolyl ligands in different hapticities with central metals {[η2:η1-µ-η1-3-(CyNCH(CH2SiMe3))Ind]RE-(thf)(CH2SiMe3)}2 (Cy = cyclohexyl, Ind = Indolyl, RE = Yb (1), Er (2), Y (3)) or {[η1-µ-η1-3-(CyNCH(CH2SiMe3))Ind]RE-(thf)2(CH2SiMe3)}2 (RE = Yb (4), Er (5), Y (6), Gd (7)), respectively. These two series of dinuclear complexes could be transferred to each other easily by only changing the solvents in the process. Reaction of [Er(CH2SiMe3)3(thf)2] with 1 equiv. of 3-t-butylaminomethylindole 3-(tBuNHCH2)C8H5NH in THF afforded the unexpected trinuclear erbium alkyl complex [η2:η1-µ-η1-3-(tBuNCH2)Ind]4Er3(thf)5(CH2SiMe3) (8), which can also be prepared by reaction of 3 equiv. of [Er(CH2SiMe3)3(thf)2] with 4 equiv. of 3-(tBuNHCH2)C8H5NH in THF. Accordingly, complexes [η2:η1-µ-η1-3-(tBuNCH2)Ind]4RE3(thf)5(CH2SiMe3) (RE = Y (9), Dy (10)) were prepared by reactions of 3 equiv. of [RE(CH2SiMe3)3(thf)2] with 4 equiv. of 3-(tBuNHCH2)C8H5NH in THF. Reactions of [RE(CH2SiMe3)3(thf)2] with 1 equiv. of 3-t-butylaminomethylindole 3-(tBuNHCH2)C8H5NH in THF, followed by treatment with 1 equiv. of [(2,6-iPr2C6H3)N[double bond, length as m-dash]CHNH(C6H3iPr2-2,6)] afforded, after workup, the dinuclear rare-earth metal complexes [η1-µ-η1:η1-3-(tBuNCH2)Ind][η1-µ-η1:η3-3-(tBuNCH2)Ind]RE2(thf)[(η3-2,6-iPr2C6H3)NCHN(C6H3iPr2-2,6)]2(RE = Er (11), Y (12)) having the indolyl ligands bonded with the rare-earth metal in different ligations. All new complexes 1-12 were fully characterized by spectroscopic methods and elemental analyses, and their structures were determined by X-ray crystallographic analyses. It was found that, except for complexes 1, 4, 11 and 12, all complexes were highly efficient catalysts for selective isoprene polymerization (up to 99% 1,4-cis selectivity) with the cooperation of co-catalysts, and the trinuclear complexes displayed advantages over dinuclear complexes in terms of molecular weight of polymers.

Reactivity of functionalized indoles with rare-earth metal amides. Synthesis, characterization and catalytic activity of rare-earth metal complexes incorporating indolyl ligands.

The reactivity of several functionalized indoles 2-(RNHCH2)C8H5NH (R = C6H5 (1), (t)Bu (2), 2,6-(i)Pr2C6H3 (3)) with rare-earth metal amides is described. Reactions of 1 or 2 with [(Me3Si)2N]3RE(µ-Cl)Li(THF)3 (RE = Eu, Yb) respectively produced the europium complexes [2-(C6H5N[double bond, length as m-dash]CH)C8H5N]2Eu[N(SiMe3)2] (4) and [2-((t)BuN[double bond, length as m-dash]CH)C8H5N]Eu[N(SiMe3)2]2 (5), and the ytterbium complex [2-((t)BuN[double bond, length as m-dash]CH)C8H5N]2Yb[N(SiMe3)2] (6), containing bidentate anionic indolyl ligands via dehydrogenation of the amine to the imine. In contrast, reactions of the more sterically bulky indole 3 with [(Me3Si)2N]3RE(µ-Cl)Li(THF)3 afforded complexes [2-(2,6-(i)Pr2C6H3NCH2)C8H5N]RE[N(SiMe3)2](THF)2 (RE = Yb (7), Y (8), Er (9), Dy (10)) with the deprotonated indolyl ligand. While reactions of 3 with yttrium and ytterbium amides in refluxing toluene respectively gave the complexes [2-(2,6-(i)Pr2C6H3N[double bond, length as m-dash]CH)C8H5N]3Y (11) and [2-(2,6-(i)Pr2C6H3N[double bond, length as m-dash]CH)C8H5N]2Yb(II)(THF)2 (12), along with transformation of the amino group to the imino group, and also with a reduction of Yb(3+) to Yb(2+) in the formation of 12. Reactions of 3 with samarium and neodymium amides provided novel dinuclear complexes {[µ-η(5):η(1):η(1)-2-(2,6-(i)Pr2C6H3NCH2)C8H5N]RE[N(SiMe3)2]}2 (RE = Sm (13), Nd (14)) having indolyl ligands in µ-η(5):η(1):η(1) hapticities. The pathway for the transformation of the amino group to the imino group is proposed on the basis of the experimental results. The new complexes displayed excellent activity in the intramolecular hydroamination of aminoalkenes.

Synthesis and Characterization of Organo-Rare-Earth Metal Monoalkyl Complexes Supported by Carbon σ-Bonded Indolyl Ligands: High Specific Isoprene 1,4-Cis Polymerization Catalysts.

A series of N-protected 3-imino-functionalized indolyl ligands 1-R-3-(R'N═CH)C8H5N [R = Bn, R' = 2,6-(i)Pr2C6H3 (HL(1)); R = CH3, R' = 2,6-(i)Pr2C6H3 (HL(2)); R = Bn, R' = (t)Bu (HL(3))] and 1-CH3-2-(2,6-(i)Pr2C6H3N═CH)C8H5N (HL(4)) was prepared via reactions of N-protected indolyl aldehydes with corresponding amines. The C-H σ-bond metathesis followed by alkane elimination reactions between RE(CH2SiMe3)3(thf)2 and HL(1)-HL(3) afforded the carbon σ-bonded indolyl-ligated rare-earth metal monoalkyl complexes. Reactions of RE(CH2SiMe3)3(thf)2 with 2 equiv of HL(1) or HL(2) gave the carbon σ-bonded indolyl-ligated rare-earth metal monoalkyl complexes L(1)2RECH2SiMe3 (RE = Y(1), Er(2), Dy(3)) and L(2)2RECH2SiMe3 (RE = Y(5), Er(6), Dy(7), Yb(8)), while reaction of Yb(CH2SiMe3)3(thf)2 with 2 equiv of HL(1) afforded the ytterbium dialkyl complex L(1)Yb(CH2SiMe3)2(thf)2 (4). Reactions of RE(CH2SiMe3)3(thf)2 with HL(3) gave the tris(heteroaryl) rare-earth metal complexes L(3)3RE (RE = Y(9), Er(10)). In the presence of cocatalysts, the rare-earth metal monoalkyl complexes initiated isoprene polymerization with a high activity (90% conversion of 1000 equiv of isoprene in 25 min) producing polymers with high regio- and stereoselectivity (1,4-cis polymers up to 99%).

Palladium-catalyzed Hiyama coupling reaction of arylsulfonyl hydrazides under oxygen.

Palladium-catalyzed Hiyama cross-coupling reactions of various arylsulfonyl hydrazides with a wide variety of aryl silanes have been achieved in good to excellent yields under simple conditions. The newly developed catalytic system does not require the use of expensive silver- or copper-based stoichiometric oxidants and can be accelerated by the addition of TBAT under an atmosphere of oxygen. The reported Hiyama-type coupling reactions are tolerant to common functional groups, making these transformations attractive alternatives to the traditional cross-coupling approaches.

Dinuclear rare-earth metal alkyl complexes supported by indolyl ligands in µ-η(2) :η(1) :η(1) hapticities and their high catalytic activity for isoprene 1,4-cis-polymerization.

Two series of new dinuclear rare-earth metal alkyl complexes supported by indolyl ligands in novel µ-η(2) :η(1) :η(1) hapticities are synthesized and characterized. Treatment of [RE(CH2 SiMe3 )3 (thf)2 ] with 1 equivalent of 3-(tBuN=CH)C8 H5 NH (L1 ) in THF gives the dinuclear rare-earth metal alkyl complexes trans-[(µ-η(2) :η(1) :η(1) -3-{tBuNCH(CH2 SiMe3 )}Ind)RE(thf)(CH2 SiMe3 )]2 (Ind=indolyl, RE=Y, Dy, or Yb) in good yields. In the process, the indole unit of L1 is deprotonated by the metal alkyl species and the imino C=N group is transferred to the amido group by alkyl CH2 SiMe3 insertion, affording a new dianionic ligand that bridges two metal alkyl units in µ-η(2) :η(1) :η(1) bonding modes, forming the dinuclear rare-earth metal alkyl complexes. When L1 is reduced to 3-(tBuNHCH2 )C8 H5 NH (L2 ), the reaction of [Yb(CH2 SiMe3 )3 (thf)2 ] with 1 equivalent of L2 in THF, interestingly, generated the trans-[(µ-η(2) :η(1) :η(1) -3-{tBuNCH2 }Ind)Yb(thf)(CH2 SiMe3 )]2 (major) and cis-[(µ-η(2) :η(1) :η(1) -3-{tBuNCH2 }Ind)Yb(thf)(CH2 SiMe3 )]2 (minor) complexes. The catalytic activities of these dinuclear rare-earth metal alkyl complexes for isoprene polymerization were investigated; the yttrium and dysprosium complexes exhibited high catalytic activities and high regio- and stereoselectivities for isoprene 1,4-cis-polymerization.

Rare-earth alkyl complexes supported by formamidinate ligands: synthesis, structure, and catalytic activity for isoprene polymerization.

A series of rare-earth metal monoalkyl complexes supported by N,N'-di(2,6-dialkylphenyl)formamidinate ligand (L)2RECH2SiMe3·thf [L(1) = HC(N-2,6-Me2C6H3)2, RE = Y (1), L(2) = HC(N-2,6-(i)Pr2C6H3)2, RE = Y (2), Er (3), Dy (4), Sm (5), and Nd (6)] were synthesized by alkyl elimination reaction or by salt metathesis reaction in good yields. All complexes were characterized by elemental analyses, FT-IR spectroscopy and single crystal X-ray diffraction. In combination with [Ph3C][B(C6F5)4] and alkylaluminium, these complexes displayed a good activity towards isoprene polymerization to give polyisoprenes with high molecular weight (M(n) > 10(4)) and narrow molecular distribution (PDI < 2.0). The influence of alkylaluminium, central metal, temperature, sequence of addition of alkylaluminium and [Ph3C][B(C6F5)4] on the polymerization of isoprene was studied. It was interesting to find that addition of the cocatalysts sequence has a great influence on the regioselectivity of the polymerization. High 1,4-regioselectivity polymerizations of isoprene (as high as 98%) were observed when the catalysts were added in the order [RE]/[alkylaluminum]/[borate].

Synthesis, structure, and catalytic activity of novel trinuclear rare-earth metal amido complexes incorporating µ-η5:η1 bonding indolyl and µ3-oxo groups.

The reactions of different pyrrolyl-functionalized indoles with rare-earth metal(III) amides [(Me3Si)2N]3RE(III)(µ-Cl)Li(THF)3 (RE = Yb, Er, Dy, Eu, Y) produced different kinds of rare-earth metal amido complexes. Reactions of N-((1H-pyrrol-2-yl)methylene)-2-(1H-indol-3-yl)ethanamine with rare-earth metal amides [(Me3Si)2N]3RE(III)(µ-Cl)Li(THF)3 (RE = Yb, Er, Dy, Eu, Y) in toluene or THF at temperatures of 75-80 °C afforded the novel trinuclear rare-earth metal amido complexes incorporating the indolyl ligand in µ-η(5):η(1) bonding modes and a µ3-O group, which is believed to originate from cleavage of the THF ring based on experimental results. Reactions of 2-(1H-indol-3-yl)-N-((1-methyl-1H-pyrrol-2-yl)methylene)ethanamine with rare-earth metal(III) amides [(Me3Si)2N]3RE(III)(µ-Cl)Li(THF)3 (RE = Yb, Dy) produced mononuclear ytterbium and dysprosium amides having the indolyl ligand in an η(1) bonding fashion. The results indicate that substituents not only have an influence on reactivity, but also have an influence on the bonding of the indolyl ligands with metals. The catalytic activities of the novel lanthanide amido complexes for the hydrophosphonylation of both aromatic and aliphatic aldehydes and ketones were explored. The results indicate that these complexes display a high catalytic activity for the C-P bond formation under mild conditions when using low catalyst loadings (0.1 mol% for aldehydes and ketones). Thus, it provides a potential way to prepare α-hydroxy phosphonates.