The Addition of an Ultra-Small Amount of Black Phosphorous Quantum Dots Endow Self-Healing Polyurethane with a Biomimetic Intelligent Response.

This study explores new applications of black phosphorus quantum dots (BPQDs) by adding them to self-healing material systems for the first time. Self-healing polyurethane with an ultra-small amount of BPQDs has biomimetic intelligent responsiveness and achieves balance between its mechanical and self-healing properties. By adding 0.0001 wt% BPQDs to self-healing polyurethane, the fracture strength of the material increases from 3.0 to 12.3 MPa, and the elongation at break also increases from 750% to 860%. Meanwhile, the self-healing efficiency remains at 98%. The addition of BPQDs significantly improves the deformation recovery ability of the composite materials and transforms the surface of self-healing polyurethane from hydrophilic to hydrophobic, making it suitable for applications in fields such as electronic skin and flexible wearable devices. This study provides a simple and feasible strategy for endowing self-healing materials with biomimetic intelligent responsiveness using a small amount of BPQDs.

Prognostic value of fibrinogen-to-albumin ratio combined with coronary calcification score in patients with suspected coronary artery disease.

OBJECTIVE: The aim of this work was to evaluate the predictive value of FAR combined with CACS for MACCEs. BACKGROUND: The fibrinogen-albumin-ratio (FAR), a novel biomarker of inflammation, is associated with the severity of coronary artery disease (CAD). Coronary calcification score (CACS) is associated with the severity of coronary stenosis and is closely related to the prognosis of CAD patients. What is the prognostic value of FAR in patients with chest pain, which has not been reported. This study aims to evaluate the relationship between CACS and FAR and their impact on prognosis in patients with suspected CAD. METHODS: We used information from 12,904 individuals who had coronary computed tomography angiography (CTA) for chest pain and tracked down any significant adverse cardiac and cerebrovascular events (MACCEs). The following formula was used to calculate FAR: fibrinogen (g/L)/albumin (g/L). Patients were separated into groups with greater levels of FAR (FAR-H) and lower levels of FAR (FAR-L) in accordance with the ideal cut-off value of FAR for MACCEs prediction. In addition, patients were divided into three groups based on their CACS scores (CACS ≤ 100, 100 < CACS ≤ 400, and CACS > 400). RESULTS: 4946 patients [62(55-71) years, 64.4% male] were ultimately enrolled in the present study. During follow-up, a total of 234 cases (4.7%) of MACCEs were documented. Linear regression analysis results showed that CACS (R2 = 0.004, Standard ß = 0.066, P < 0.001) was positively associated with FAR in patients with chest pain.Compared to ones with FAR-L, FAR-H had an increased risk for MACCEs (adjusted HR 1.371(1.053-1.786) P = 0.019). Multivariate Cox regression showed that age (adjusted HR 1.015 95% CI 1.001-1.028;p = 0.03), FAR (adjusted HR 1.355 95% CI 1.042-1.763;p = 0.023),FBG (adjusted HR 1.043 95% CI 1.006-1.083;p = 0.024) and CACS (adjusted HR 1.470 95% CI 1.250-1.727;p < 0.001) were the independent risk factors for MACCEs. The FAR and CACS significantly improved MACCEs risk stratification, contributing to substantial net reclassification improvement ( NRI 0.122, 95% CI 0.054-0.198, P < 0.001) and integrated discrimination improvement(IDI 0.011, 95% CI 0.006-0.017, P < 0.001). CONCLUSION: FAR was an independent risk factor for MACCEs. The results showed that CACS was positively associated with FAR in patients with suspected CAD. A higher level of FAR and heavier coronary calcification burden was associated with worse outcomes among patients with suspected CAD. FAR and CACS improved the risk identification of patients with suspected CAD, leading to a significant reclassification of MACCEs.

Connectivity Replication of Neutral Eu3+- and Tb3+-Based Metal-Organic Frameworks (MOFs) from Anionic Cd2+-Based MOF Crystallites.

Neutral three-dimensional Eu3+- and Tb3+-based metal-organic frameworks (MOFs) with 4-fold interpenetration can be produced by seeding with anionic Cd2+-based MOF crystallites of identical connectivity. In the absence of these crystallites, two-dimensional networks are formed.

Fluxional bonds in quasi-planar B 18 2 - and half-sandwich MB 18 - (M = K, Rb, and Cs).

Detailed molecular orbital and bonding analyses reveal the existence of both fluxional σ- and π-bonds in the global minima Cs B 18 2 - (1) and Cs MB18 (3) and transition states Cs B 18 2 - (2) and Cs MB 18 - (4) of B 18 2 - dianion and MB 18 - monoanions (M = K, Rb, and Cs). It is the fluxional bonds that facilitate the fluxional behaviors of the quasi-planar B 18 2 - and half-sandwich MB 18 - which possess energy barriers smaller than the difference of the corresponding zero-point corrections. © 2019 Wiley Periodicals, Inc.

Aromatic cage-like B34 and B35+: new axially chiral members of the borospherene family.

Shortly after the discovery of all-boron fullerenes D2d B40-/0 (borospherenes), the first axially chiral borospherenes C3/C2 B39- were characterized in experiments in 2015. Based on extensive global minimum searches and first-principles theory calculations, we present herein two new axially chiral members to the borospherene family: the aromatic cage-like C2 B34(1) and C2 B35+(2). Both B34(1) and B35+(2) feature one B21 boron triple chain on the waist and two equivalent heptagons and hexagons on the cage surface, with the latter being obtained by the addition of B+ into the former at the tetracoordinate defect site. Detailed bonding analyses show that they follow the universal bonding pattern of σ + π double delocalization, with 11 delocalized π bonds over a σ skeleton. Extensive molecular dynamics simulations show that these borospherenes are kinetically stable below 1000 K and start to fluctuate at 1200 K and 1100 K, respectively. The IR, Raman, and UV-vis spectra of 1 and 2 are computationally simulated to facilitate their experimental characterization.

Double-ring tubular (B2O2)n clusters (n = 6-42) rolled up from the most stable BO double-chain ribbon in boron monoxides.

Based on extensive global searches and first-principles theory calculations, we present herein the possibility of double-ring tubular (B2O2)n clusters (n = 6-42) (2-10) rolled up from the most stable one-dimensional (1D) BO double-chain ribbon (1) in boron monoxides. Tubular (3D) (B2O2)n clusters (n ≥ 6) are found to be systematically much more stable than their previously proposed planar (2D) counterparts, with a 2D-3D structural transition at B12O12 (2). Detailed bonding analyses on 3D (B2O2)n clusters (2-10) and their precursor 1D BO double-chain ribbon (1) reveal two delocalized B-O-B 3c-2e π bonds over each edge-sharing B4O2 hexagonal unit which form a unique 6c-4e o-bond to help stabilize the systems. The IR, Raman, UV-vis, and photoelectron spectra of the concerned species are computationally simulated to facilitate their experimental characterization.

Structural transition in metal-centered boron clusters: from tubular molecular rotors Ta@B21 and Ta@B22+ to cage-like endohedral metalloborospherene Ta@B22.

Inspired by the recent discovery of the metal-centered tubular molecular rotor Cs B2-Ta@B18- with the record coordination number of CN = 20 and based on extensive first-principles theory calculations, we present herein the possibility of the largest tubular molecular rotors Cs B3-Ta@B18 (1) and C3v B4-Ta@B18+ (2) and smallest axially chiral endohedral metalloborospherenes D2 Ta@B22- (3 and 3'), unveiling a tubular-to-cage-like structural transition in metal-centered boron clusters at Ta@B22-via effective spherical coordination interactions. The highly stable Ta@B22- (3) as an elegant superatom, which features two equivalent corner-sharing B10 boron double chains interconnected by two B2 units with four equivalent B7 heptagons evenly distributed on the cage surface, conforms to the 18-electron configuration with a bonding pattern of σ + π double delocalization and follows the 2(n + 1)2 electron counting rule for spherical aromaticity (n = 2). Its calculated adiabatic detachment energy of ADE = 3.88 eV represents the electron affinity of the cage-like neutral D2 Ta@B22 which can be viewed as a superhalogen. The infrared, Raman, VCD, and UV-vis spectra of the concerned species are computationally simulated to facilitate their spectral characterizations.

Pseudoalteromonas fenneropenaei sp. nov., a marine bacterium isolated from sediment of a Fenneropenaeus chinensis pond.

A novel Gram-stain-negative, motile, oxidase- and catalase-positive, non-spore-forming, non-pigmented, aerobic bacterium, designated rzy34T, was isolated from the sediment of a pond containing farmed Fenneropenaeus chinensis Rizhao, China. The strain was able to grow at pH 6-10 (optimum pH 7), 20-40 °C (optimum 30 °C) and in the presence of 1.0-6.0 % NaCl (optimum 1.0-2.0 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that the nearest relative of strain rzy34T was Pseudoalteromonas xiamenensis Y2T, with the highest sequence similarity of 96.09 %. Within the genus Pseudoalteromonas, it showed the lowest similarity of 92.7 % to Pseudoalteromonas donghaensis. The G+C content of the chromosomal DNA of strain rzy34T was 45.3 mol%. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0, C17 : 1ω8c and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The major respiratory quinone was Q-8. Polar lipid analysis indicated the presence of phosphatidylethanolamine and phosphatidylcholine. On the basis of the phenotypic and phylogenetic characteristics, strain rzy34T represents a novel species of the genus Pseudoalteromonas, for which the name Pseudoalteromonas fenneropenaei sp. nov. is proposed. The type strain is rzy34T (=CGMCC 1.15325T=KCTC 42730T).

Brassicibacter thermophilus sp. nov., a thermophilic bacterium isolated from coastal sediment.

A novel thermophilic, obligately anaerobic bacterium, strain Cel2f(T), was isolated from a cellulolytic community enriched from coastal marine sediment. Cells were Gram-stain-negative, non-motile, non-spore-forming and rod-shaped. Optimal growth temperature and pH of strain Cel2f(T) were 55 °C and pH 7.0, respectively. NaCl was essential for the growth of strain Cel2f(T) and the strain showed enhanced growth in the presence of sea salt; the optimum sea salt concentration for growth was 7% (w/v). Thiosulfate, sulfate and sulfite were potential electron acceptors. The major fatty acids of strain Cel2f(T) were iso-C15 : 0, C16 : 0, and C18 : 0. Polar lipid analysis indicated the presence of phosphatidylethanolamine and phosphatidylglycerol. Strain Cel2f(T) contained menaquinone MK-7 as the isoprenoid quinone, and the DNA G+C content was 31.3 mol%. Phylogenetic analysis revealed that the nearest relative of strain Cel2f(T) was Brassicibacter mesophilus BM(T) with 93.8% 16S rRNA gene sequence similarity. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain Cel2f(T) represents a novel species of genus Brassicibacter, for which the name Brassicibacter thermophilus sp. nov. is proposed. The type strain is Cel2f(T) ( = JCM 30480(T) = CGMCC 1.5200(T)).

Correction: Aromatic amine electrochemical sensors based on a Co-MOF: a hydrogen bond-induced specific response.

Correction for 'Aromatic amine electrochemical sensors based on a Co-MOF: a hydrogen bond-induced specific response' by Xiao-qin Wu et al., Dalton Trans., 2022, 51, 16861-16869, https://doi.org/10.1039/d2dt02049a.

Coronary artery calcium and cystatin C for risk stratification of MACCEs and all-cause death in symptomatic patients.

OBJECTIVES: The aim of this study was to examine the independent and joint associations of baseline coronary artery calcium score (CACS) and cystatin C (Cys-C) with the risk of major adverse cardiac and cerebrovascular events (MACCEs) and all-cause death in symptomatic populations. METHODS: The study included 7140 patients with symptom of chest pain who underwent cardiac computerized tomography examinations to measure CACS. All of them had serum Cys-C results. Endpoints were set for MACCEs and all-cause death events. RESULTS: A total of 7140 participants were followed for a median of 1106 days. A total of 305 patients had experienced MACCEs and 191 patients had experienced all-cause death. CACS ≥ 100 and Cys-C ≥ 0.995 mg/L were independently associated with an increased risk of MACCEs (adjusted hazard ratio [HR]: 1.46; 95% confidence interval [CI]: 1.15-1.85; p = .002 and adjusted HR: 1.57; 95% CI: 1.24-2.00; p < .001, respectively). Compared with CACS < 100 and Cys-C < 0.995 mg/L patients, CACS ≥ 100 and Cys-C ≥ 0.995 mg/L patients had the highest risk of MACCEs and all-cause death (adjusted HR: 2.33; 95% CI: 1.64-3.29; p < .001 and adjusted HR: 2.85; 95% CI: 1.79-4.55; p < .001, respectively). Even in patients with CACS < 100, Cys-C ≥ 0.995 mg/L was also associated with a higher risk of MACCEs and all-cause death than Cys-C < 0.995 mg/L (adjusted HR: 1.76; p = .003 and adjusted HR: 2.02; p = .007, respectively). CONCLUSIONS: The combined stratification of CACS and Cys-C showed an incremental risk of MACCEs and all-cause death, reflecting complementary prognostic value. Our results support the combination of the two indicators for risk stratification and event prediction.

Aromatic amine electrochemical sensors based on a Co-MOF: a hydrogen bond-induced specific response.

A 2D Co-MOF, {[Co2(L2-)2(bipy)](DMA)·2H2O}n (Co-1, H2L = 2,5-thienedioic acid; bipy = 2,2'-bipyridine; DMA = N,N'-dimethyl acetamide), was synthesized by hydrothermal method. Co-1 has excellent air stability. When modifying the surface of a glassy carbon electrode (GCE) with Co-1, the obtained electrochemical senor Co-1/GCE shows excellent sensitivity towards 1,3-dinitrobenzene (m-DNB) and 2,4-dinitroaniline (2,4-DNA), although the electrochemical conductivity of Co-1 is not that good. The detection limits were as low as 0.0286 µM and 0.161 µM, respectively. DFT studies showed that the main interaction between Co-1 and the guest molecules is via hydrogen bonding, formed by the -NO2 group and the coordinated H2O molecule from the Co-1 skeleton. Furthermore, the characteristic signals of both m-DNB and 2,3-DNA can still be observed in a mimicked industrial waste-water system containing 17 kinds of organic interferents, indicating high selectivity of the Co-1/GCE sensor.

ZIF-8 with cationic defects toward efficient 125I2 uptake for in vitro radiotherapy of colon cancer.

Introducing 2,3-dimethyl-1H-imidazol-3-ium iodide (Dmim) as a monodentate ligand during the preparation of ZIF-8 yields ZIF-8 + (50) and ZIF-8 + (38) with cationic 'missing linker' defects. ZIF-8 + (38) adsorbs 125I2 and the resulting radioactive host-guest complex exhibits in vitro cytotoxicity comparable to that of Na125I against colon cancer cell line CT26.

Prognostic value of the PDW/HDL-C ratio in patients with chest pain symptoms and coronary artery calcification.

Background: Platelet-related parameters and HDL-C have been regarded as reliable and alternative markers of coronary heart disease (CHD) and the independent predictors of cardiovascular outcomes. PDW is a simple platelet index, which increases during platelet activation. Whether the PDW/HDL-C ratio predicts major adverse cardiovascular and cerebrovascular events (MACCEs) in patients who complained of chest pain and confirmed coronary artery calcification remains to be investigated. This study aimed to investigate the prognostic value of the PDW/HDL-C ratio in patients with chest pain symptoms and coronary artery calcification. Methods: A total of 5,647 patients with chest pain who underwent coronary computer tomography angiography (CTA) were enrolled in this study. Patients were divided into two groups according to their PDW/HDL-C ratio or whether the MACCE occurs. The primary outcomes were new-onset MACCEs, defined as the composite of all-cause death, non-fatal MI, non-fatal stroke, revascularization, malignant arrhythmia, and severe heart failure. Results: All patients had varying degrees of coronary calcification, with a mean CACS of 97.60 (22.60, 942.75), and the level of CACS in the MACCEs group was significantly higher than that in non-MACCE (P<0.001). During the 89-month follow-up, 304 (5.38%) MACCEs were recorded. The incidence of MACCEs was significantly higher in patients with the PDW/HDL-C ratio > 13.33. The K-M survival curves showed that patients in the high PDW/HDL-C ratio group had significantly lower survival rates than patients in the low PDW/HDL-C ratio group (log-rank test: P < 0.001). Multivariate Cox hazard regression analysis reveals that the PDW/HDL ratio was an independent predictor of MACCEs (HR: 1.604, 95% CI: 1.263-2.035; P < 0.001). Cox regression analysis showed that participants with a lower PDW/HDL-C ratio had a higher risk of MACCEs than those in the higher ratio group. The incidence of MACCEs was also more common in the PDW/HDL-C ratio > 13.33 group among different severities of coronary artery calcification. Furthermore, adding the PDW/HDL-C ratio to the traditional prognostic model for MACCEs improved C-statistic (P < 0.001), the NRI value (11.3% improvement, 95% CI: 0.018-0.196, P = 0.01), and the IDI value (0.7% improvement, 95% CI: 0.003-0.010, P < 0.001). Conclusion: The higher PDW/HDL-C ratio was independently associated with the increasing risk of MACCEs in patients with chest pain symptoms and coronary artery calcification. In patients with moderate calcification, mild coronary artery stenosis, and CAD verified by CTA, the incidence of MACCEs increased significantly in the PDW/HDL-C ratio > 13.33 group. Adding the PDW/HDL-C ratio to the traditional model provided had an incremental prognostic value for MACCEs.

Synaptosomal-Associated Protein 25 Gene Polymorphisms Affect Treatment Efficiency of Methylphenidate in Children With Attention-Deficit Hyperactivity Disorder: An fNIRS Study.

Methylphenidate (MPH) is the first-line drug for the treatment of children with attention-deficit hyperactivity disorder (ADHD); however, individual curative effects of MPH vary. Many studies have demonstrated that synaptosomal-associated protein 25 (SNAP-25) gene MnlI polymorphisms may be related to the efficacy of MPH. However, the association between SNAP-25MnlI polymorphisms and changes in brain hemodynamic responses after MPH treatment is still unclear. This study used functional near-infrared spectroscopy (fNIRS) to preliminarily investigate the interaction of MPH treatment-related prefrontal inhibitory functional changes with the genotype status of the SNAP-25 gene in children with ADHD. In total, 38 children with ADHD aged 6.76-12.08 years were enrolled in this study and divided into the following two groups based on SNAP-25 gene MnlI polymorphisms: T/T genotype group (wild-type group, 27 children) and G allele carrier group (mutation group, 11 children). The averaged oxygenated hemoglobin concentration changes [Δavg oxy-Hb] and deoxyhemoglobin concentration changes [Δavg deoxy-Hb] in the frontal cortex before MPH treatment and after 1.5 h (post-MPH1.5h) and 4 weeks (post-MPH4w) of MPH treatments were monitored using fNIRS during the go/no-go task. SNAP-IV scores were evaluated both pre-MPH and post-MPH4w treatments. In the T/T genotype group, [Δavg oxy-Hb] in the dorsolateral prefrontal cortex was significantly higher after 4 weeks of MPH (post-MPH4W) treatment than pre-treatment; however, in the G allele group, no significant differences in [Δavg oxy-Hb] were observed between pre- and post-treatments. In the go/no-go task, the accuracy was significantly increased post-MPH4w treatment in the T/T genotype group, while no significant differences were observed in response time and accuracy of the "go" sand no-go task in the G allele group for pre-MPH, post-MPH1.5h, and post-MPH4w treatments. The T/T genotype group exhibited a significant decrease in SNAP-IV scores after MPH treatment, while the G allele group showed no significant difference. In conclusion, fNIRS data combined with SNAP-25 MnlI polymorphism analysis may be a useful biomarker for evaluating the effects of MPH in children with ADHD.

B48-: a bilayer boron cluster.

Size-selected negatively-charged boron clusters (Bn-) have been found to be planar or quasi-planar in a wide size range. Even though cage structures emerged as the global minimum at B39-, the global minimum of B40- was in fact planar. Only in the neutral form did the B40 borospherene become the global minimum. How the structures of larger boron clusters evolve is of immense interest. Here we report the observation of a bilayer B48- cluster using photoelectron spectroscopy and first-principles calculations. The photoelectron spectra of B48- exhibit two well-resolved features at low binding energies, which are used as electronic signatures to compare with theoretical calculations. Global minimum searches and theoretical calculations indicate that both the B48- anion and the B48 neutral possess a bilayer-type structure with D2h symmetry. The simulated spectrum of the D2h B48- agrees well with the experimental spectral features, confirming the bilayer global minimum structure. The bilayer B48-/0 clusters are found to be highly stable with strong interlayer covalent bonding, revealing a new structural type for size-selected boron clusters. The current study shows the structural diversity of boron nanoclusters and provides experimental evidence for the viability of bilayer borophenes.

Perfect cubic La-doped boron clusters La6&[La@B24]+/0 as the embryos of low-dimensional lanthanide boride nanomaterials.

La-doped boron nanoclusters have received considerable attention due to their unique structures and bonding. Inspired by recent experimental observations of the inverse sandwich D 8h La2B8 (1) and triple-decker C 2v La3B14 - (2) and based on extensive global searches and first-principles theory investigations, we present herein the possibility of the perfect cubic La-doped boron clusters O h La6&[La@B24]+ (3, 1A1g) and O h La6&[La@B24] (4, 2A2g) which appear to be the embryos of the metallic one-dimensional La10B32 (5) nanowire, two-dimensional La3B10 (6) nanosheet, and three-dimensional LaB6 (7) nanocrystal, facilitating a bottom-up approach to build cubic lanthanide boride nanostructures from gas-phase clusters. Detailed molecular orbital and bonding analyses indicate that effective (d-p)σ, (d-p)π and (d-p)δ covalent coordination interactions exist in La6&[La@B24]+/0 (3/4) clusters, while the 1D La10B32 (5), 2D La3B10 (6), and 3D LaB6 (7) crystals exhibit mainly electrostatic interactions between the trivalent La centers and cubic B24 frameworks, with weak but discernible coordination contributions from La (5d) ← B (2p) back-donations. The IR and Raman spectra of La6&[La@B24]+/0 (3/4) and band structures of La10B32 (5) and La3B10 (6) are computationally simulated to facilitate their future characterizations.

Novel B-C binary fullerenes following the isolated B4C3 hexagonal pyramid rule.

B-C binary monolayers and fullerenes (borafullerenes) have received considerable attention in recent years. Inspired by the newly reported B4C3 semiconducting boron carbide monolayer isovalent to graphene (Tian et al., Nanoscale, 2019, 11, 11099), we predict herein at density functional theory level a new class of borafullerenes (1-8) following the isolated B4C3 hexagonal pyramid rule. The spherically aromatic borafullerenes C5h B20C35 (1), C5 B20C45 (2), C5h B20C55 (3), and C5 B20C65 (4) isovalent to C50, C60, C70, and C80, respectively, possess five isolated B4C3 hexagonal pyramids evenly distributed on the waist around the C5 molecular axis, while S10 B40C50 (5), C5 B40C60 (6), S10 B40C70 (7), and C5 B40C80 (8) encompass ten isolated B4C3 pyramids symmetrically distributed on the cage surface. Detailed orbital and bonding analyses indicate that these borafullerenes follow similar σ and π-bonding patterns with their fullerene analogues, with three delocalized 7c-2e π bonds forming a local π-aromatic system over each isolated B4C3 hexagonal pyramid. The calculated formation energies of the (B4C3)nC60-6n (n = 1-5) series isovalent to C60 appear to increase almost linearly with the number of isolated B4C3 pyramids in the system. The IR, Raman, and UV-vis spectra of the prototypical B20C45 (2) are theoretically simulated to facilitate its future spectral characterization.

Probing the Fluxional Bonding Nature of Rapid Cope rearrangements in Bullvalene C10H10 and Its Analogs C8H8, C9H10, and C8BH9.

Bullvalene C10H10 and its analogs semibullvalene C8H8, barbaralane C9H10, and 9-Borabarbaralane C8BH9 are prototypical fluxional molecules with rapid Cope rearrangements at finite temperatures. Detailed bonding analyses performed in this work reveal the existence of two fluxional π-bonds (2 2c-2e π → 2 3c-2e π → 2 2c-2e π) and one fluxional σ-bond (1 2c-2e σ → 1 4c-2e σ → 1 2c-2e σ) in their ground states and transition states, unveiling the universal π + σ double fluxional bonding nature of these fluctuating cage-like species. The highest occupied natural bond orbitals (HONBOs) turn out to be typical fluxional bonds dominating the dynamics of the systems. The 13C-NMR and 1H-NMR shielding tensors and chemical shifts of the model compound C8BH9 are computationally predicted to facilitate future experiments.

Predicting lanthanide boride inverse sandwich tubular molecular rotors with the smallest core-shell structure.

Lanthanide-boron binary clusters possess interesting structures and bonding which may provide insights into designing new boride nanomaterials. Inspired by the recently discovered mono-decker inverse sandwich D9h La2B9- (1A'1) (1) and based on the extensive first-principles theory calculations, we predict herein the possible existence of a series of bi-decker inverse sandwich di-lanthanide boron complexes including D9d La2[B18] (3A1g) (2), D9d La2[B18]2- (1A1g) (3), and C2h La2[B2@B18] (1Ag) (4) which all contain a tubular Bn ligand (n = 18, 20) sandwiched by two La atoms at the two ends. In these novel clusters, La2[B2@B18] (4) as a tubular molecular rotor with the smallest core-shell structure reported to date in boron-based nanoclusters possesses a B2-bar rotating constantly and almost freely inside the B18 tube around it at room temperature. Detailed bonding analyses indicate that these complexes are stablized by effective (d-p)σ, (d-p)π, and (d-p)δ coordination interactions between the La centers and Bn bi-decker ligand. Six multi-center fluxional σ-bonds between the B2-core and B18 tube in La2[B2@B18] (4) are found to be responsible for its unique fluxional behaviors. The IR and Raman spectra of the concerned species are simulated to facilitate their experimental characterization.