Primary Care Physicians' and Patients' Perspectives on Equity and Health Security of Infectious Disease Digital Surveillance.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic facilitated the rapid development of digital detection surveillance (DDS) for outbreaks. This qualitative study examined how DDS for infectious diseases (ID) was perceived and experienced by primary care physicians and patients in order to highlight ethical considerations for promoting patients' autonomy and health care rights. METHODS: In-depth interviews were conducted with a purposefully selected group of 16 primary care physicians and 24 of their patients. The group was reflective of a range of ages, educational attainment, and clinical experiences from urban areas in northern and southern China. Interviews were audio recorded, transcribed, and translated. Two researchers coded data and organized it into themes. A third researcher reviewed 15% of the data and discussed findings with the other researchers to assure accuracy. RESULTS: Five themes were identified: ambiguity around the need for informed consent with usage of DDS; importance of autonomous decision making; potential for discrimination against vulnerable users of DDS for ID; risk of social inequity and disparate care outcomes; and authoritarian institutions' responsibility for maintaining health data security. The adoption of DDS meant some patients would be reluctant to go to the hospital for fear of either being discriminated against or forced into quarantine. Certain groups (older people and children) were thought to be vulnerable to DDS misappropriation. CONCLUSIONS: These findings indicate the paramount importance of establishing national and international ethical frameworks for DDS implementation. Frameworks should guide all aspects of ID surveillance, addressing privacy protection and health security, and underscored by principles of social equity and accountability.Annals "Online First" article.

Radical Scavenging Capability and Mechanism of Three Isoflavonoids Extracted from Radix Astragali: A Theoretical Study.

As a valuable traditional Chinese herbal medicine, Radix Astragali has attracted much attention due to its extensive pharmacological activities. In this study, density functional theory (DFT) was used thermodynamically and kinetically in detail to predict the antioxidant activity and reaction mechanisms involved in the free radical scavenging reactions of three representative isoflavonoids (formononetin, calycosin, and calycosin-7-glucoside) extracted from Radix Astragali. Three main mechanisms, including hydrogen atom transfer (HAT), proton transfer after electron transfer (SET-PT), and sequential proton loss electron transfer (SPLET) were examined by calculating the thermodynamic parameters. It was found that HAT is the predominant mechanism in the gas phase, while SPLET is supported in the solvent environment. The isoflavonoids' order of antioxidant activity was estimated as: calycosin > calycosin-7-glucoside > formononetin. For the calycosin compound, the result revealed the feasibility of double HAT mechanisms, which involve the formation of stable benzodioxazole with significantly reduced energy in the second H+/e- reaction. In addition, the potential energy profiles and kinetic calculations show that the reaction of •OH into the 3'-OH site of calycosin has a lower energy barrier (7.2 kcal/mol) and higher rate constant (4.55 × 109 M-1 s-1) compared with other reactions in the gas phase.

Sc@B28-, Ti@B28, V@B28+, and V@B292-: Spherically Aromatic Endohedral Seashell-like Metallo-Borospherenes.

Transition-metal-doped boron nanoclusters exhibit unique structures and bonding in chemistry. Using the experimentally observed seashell-like borospherenes C2 B28-/0 and Cs B29- as ligands and based on extensive first-principles theory calculations, we predict herein a series of novel transition-metal-centered endohedral seashell-like metallo-borospherenes C2 Sc@B28- (1), C2 Ti@B28 (2), C2 V@B28+ (3), and Cs V@B292- (4) which, as the global minima of the complex systems, turn out to be the boron analogues of dibenzenechromium D6h Cr(C6H6)2 with two B12 ligands on the top and bottom interconnected by four or five corner boron atoms on the waist and one transition-metal "pearl" sandwiched at the center in between. Detailed molecular orbital, adaptive natural density partitioning (AdNDP), and iso-chemical shielding surface (ICSS) analyses indicate that, similar to Cr(C6H6)2, these endohedral seashell-like complexes follow the 18-electron rule in bonding patterns (1S21P61D10), rendering spherical aromaticity and extra stability to the systems.

Lanthanide/actinide boride nanoclusters and nanomaterials based on boron frameworks consisting of conjoined Bn rings (n = 7-9).

Extensive global minimum searches augmented with first-principles theory calculations performed in this work indicate that the experimentally observed perfect inverse sandwich lanthanide boride complexes D7h La2B7- (1), D8h La2B8 (3), D9h La2B9- (7) can be extended to their actinide counterparts C2v Ac2B7- (1'), D8h Ac2B8 (3'), D9h Ac2B9- (7') with a Bn monocyclic ring (n = 7-9) sandwiched by two Ac dopants. Such M2Bn-/0 inverse sandwiches (1/1', 3/3', 7/7') can be used as building blocks to generate the ground-state C2 La4B13- (2)/Ac4B13- (2'), D2 La4B15- (4)/Ac4B15- (4'), C3v/C3 La4B18 (5)/Ac4B18 (5'), Oh Ac7B24+ (6'), Oh Ac7B24, Td Ac4B24 (8'), C1 La5B24+ (9)/Ac5B24+ (9'), and Td Ac4B29- (10') which are based on boron frameworks consisting of multiple conjoined Bn rings (n = 7-9). Detailed bonding analyses show that effective (d-p)σ, (d-p)π and (d-p)δ coordination bonds are formed between the Bn rings and metal doping centers, conferring three-dimensional aromaticity and extra stability to the systems. In particular, the perfect body-centered cubic Oh Ac7B24+ (6') and Oh Ac7B24 with six conjoined B8 rings can be extended in x, y, and z dimensions to form one-dimensional Ac10B32 (11'), two-dimensional Ac3B10 (12'), and three-dimensional AcB6 (13') nanomaterials, presenting a B8-based bottom-up approach from metal boride nanoclusters to their low-dimensional nanomaterials.

La@[La5&B30]0/-/2-: endohedral trihedral metallo-borospherenes with spherical aromaticity.

It is well-known that transition-metal-doping induces dramatic changes in the structures and bonding of small boron clusters, as demonstrated by the newly observed perfect inverse sandwich D8h [La(η8-B8)La] and D9h [La(η9-B9)La]-. Based on extensive global minimum searches and first-principles theory calculations, we predict herein the possibility of perfect endohedral trihedral metallo-borospherene D3h La@[La5&B30] (1, 3A'1) and its monoanion Cs La@[La5&B30]- (2, 2A') and dianion D3h La@[La5&B30]2- (3, 1A'1). These La-doped boron clusters are composed of three inverse sandwich La(η8-B8)La on the waist and two inverse sandwich La(η9-B9)La on the top and bottom which share one apex La atom at the center and six periphery B2 units between neighboring η8-B8 and η9-B9 rings, with three octo-coordinate La atoms and two nona-coordinate La atoms as integrated parts of the cage surface. Detailed adaptive natural density partitioning (AdNDP) and iso-chemical shielding surface (ICSS) analyses indicate that La@[La5&B30]0/-/2- (1/2/3) are spherically aromatic in nature. The one-dimensional nanowire La4B21 (4, P31m) constructed from D3h La@[La5&B30] (1) along the C3 axis of the system appears to be metallic. The IR and Raman spectra of La@[La5&B30] (1) and photoelectron spectroscopy of the slightly distorted Cs La@[La5&B30]- (2) are theoretically simulated to facilitate their spectroscopic characterizations.

The unified quantum mechanical structure of tubular molecular rotors with multiple equivalent global minimum structures: the 18*C2h → D9d case of La-[B2@B18]-La.

La-[B2@B18]-La demonstrates decisive changes of the properties of molecular rotors, from multiple (here 18) equivalent individual global minimum structures to a quantum mechanical unified structure. This affects their geometries, their symmetries (18*C2h → D9d), the generation of energy bands, and high-resolution spectroscopy.

Ethics, Integrity, and Retributions of Digital Detection Surveillance Systems for Infectious Diseases: Systematic Literature Review.

BACKGROUND: The COVID-19 pandemic has increased the importance of the deployment of digital detection surveillance systems to support early warning and monitoring of infectious diseases. These opportunities create a "double-edge sword," as the ethical governance of such approaches often lags behind technological achievements. OBJECTIVE: The aim was to investigate ethical issues identified from utilizing artificial intelligence-augmented surveillance or early warning systems to monitor and detect common or novel infectious disease outbreaks. METHODS: In a number of databases, we searched relevant articles that addressed ethical issues of using artificial intelligence, digital surveillance systems, early warning systems, and/or big data analytics technology for detecting, monitoring, or tracing infectious diseases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and further identified and analyzed them with a theoretical framework. RESULTS: This systematic review identified 29 articles presented in 6 major themes clustered under individual, organizational, and societal levels, including awareness of implementing digital surveillance, digital integrity, trust, privacy and confidentiality, civil rights, and governance. While these measures were understandable during a pandemic, the public had concerns about receiving inadequate information; unclear governance frameworks; and lack of privacy protection, data integrity, and autonomy when utilizing infectious disease digital surveillance. The barriers to engagement could widen existing health care disparities or digital divides by underrepresenting vulnerable and at-risk populations, and patients' highly sensitive data, such as their movements and contacts, could be exposed to outside sources, impinging significantly upon basic human and civil rights. CONCLUSIONS: Our findings inform ethical considerations for service delivery models for medical practitioners and policymakers involved in the use of digital surveillance for infectious disease spread, and provide a basis for a global governance structure. TRIAL REGISTRATION: PROSPERO CRD42021259180; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=259180.

International incidence trends in early- and late-onset colorectal cancer: a population-based study.

PURPOSE: Knowing the global incidence of colorectal cancer (CRC), by sex and age of onset, is of great importance for understanding the disease burden of CRC. METHODS: The CRC incidence data, by cancer site, age of onset, sex, country, and year, were retrieved from the Cancer Incidence in Five Continents Vol. Plus database. Estimated annual percentage changes (EAPC) were calculated to quantify the temporal trends in the CRC age-standardized incidence rate. RESULTS: Globally, the incidence of late-onset CRC was heterogeneous and remained increasing in most countries. The highest incidence of late-onset colon and rectal cancer was both found in males in Slovakia (156.5/100,000 and 121.5/100,000, respectively). The most pronounced increases were mostly observed in developing countries, such as Brazil (colon cancer: EAPC = 5.87, 95% CI 3.18, 8.63; rectal cancer: EAPC = 4.68; 95% CI 2.78, 6.62). The highest incidence of early-onset colon and rectal cancer was found in females in Switzerland (4.2/100,000) and in males in South Korea (4.6/100,000), respectively. The incidences of early-onset CRC were increased in parts of countries, including countries experiencing a decline in late-onset CRC incidence, such as the USA, Germany, and Australia. The temporal trends of colon cancer were mostly aligned with those of rectal in most countries, independent of sex and age of onset. CONCLUSION: The increase of early-onset CRC incidence suggests more prevention initiatives are urgently warranted for young adults in the near future. Targeted and effective prevention measures are still needed among elderly populations.

Fluxional Bonds in Planar B19 - , Tubular Ta@B20 - , and Cage-Like B39.

Based on detailed bonding analyses on the fluxional behaviors of planar B19 - , tubular Ta@B20 - , and cage-like B39 - , we propose the concept of fluxional bonds in boron nanoclusters as an extension of the classical localized bonds and delocalized bonds in chemistry. © 2018 Wiley Periodicals, Inc.

[Changes in the expression of EphA5/ephrinA5 in the CA3 region of the hippocampus in rats with epilepsy and their role in the pathogenesis of temporal lobe epilepsy].

OBJECTIVE: To investigate the changes in the expression of EphA5 and its ligand ephrinA5 in the hippocampus of rats with epilepsy and their role in the pathogenesis of temporal lobe epilepsy (TLE). METHODS: A total of 240 Sprague-Dawley rats were randomly divided into control group and TLE group, with 120 rats in each group. A rat model of lithium-pilocarpine TLE was established, and then the rats were divided into subgroups at 12 and 24 hours and 7, 15, 30, and 60 days after epilepsy was induced. In-situ hybridization was used to measure the mRNA expression of ephrinA5 in the CA3 region and the dentate gyrus of the hippocampus in 9 rats; immunohistochemistry was used to measure the protein expression of EphA5 in the CA3 region and the dentate gyrus of the hippocampus in 9 rats; Neo-Timm silver staining was used to observe mossy fiber sprouting in the CA3 region of the hippocampus in 2 rats. RESULTS: In-situ hybridization showed mRNA expression of ephrinA5 in the CA3 region of the hippocampus, but this was not found in the dentate gyrus. Compared with the control group at the same time point, the TLE group had a significant reduction in the mRNA expression of ephrinA5 in the CA3 region of the hippocampus at 7 and 15 days after epilepsy was induced (P<0.05); at 30 and 60 days after epilepsy was induced, the TLE group had a gradual increase in the mRNA expression of ephrinA5 in the CA3 region of the hippocampus, and there was no significant difference between the TLE and control groups (P>0.05). Immunohistochemistry showed that EphA5 protein was expressed in the CA3 region and the dentate gyrus of the hippocampus and had a similar trend of change as ephrinA5 mRNA. Neo-Timm silver staining showed that the TLE group developed marked mossy fiber sprouting in the CA3 region of the hippocampus at 7 and 15 days after epilepsy was induced. CONCLUSIONS: Downregulation of ephrinA5 and EphA5 in the CA3 region of the hippocampus may participate in the mechanism of mossy fiber sprouting and is closely associated with the development and progression of epilepsy.

[The influence of intracellular keratin 8 on hepatitis C virus replication].

The level of intracellular keratin 8(KRT-8) is associated with liver diseases, whose expression is increased in hepatitis C virus(HCV)-infected patients with hepatocarcinoma and in cultural cells infected with HCV. However, it is not clear whether KRT-8 will impact HCV replication. In this paper, the HCV replication was analyzed in response to high expression and silence of KRT-8. The inhibitory activities against wild-type and mutant HCV were also analyzed by silence of KRT-8 or combined with known anti-HCV drug telaprevir. Results showed that the protein level of KRT-8 was increased in proportion with the HCV replication. The high expression was found to facilitate HCV replication, while the silence of KRT-8 was able to inhibit HCV replication and enhanced the anti-HCV activity of telaprevir. It also inhibited A156 T and D168 V mutant HCV, which are resistant to protease inhibitors. These results suggest that KRT-8 is a co-factor for HCV replication. Down-regulation of KRT-8 can inhibit wild type and mutant HCV replication to enhance the anti-HCV activity of known anti-HCV drugs. Therefore, KRT-8 may be a new target in the development of anti-HCV agents.

[Analysis on 315 cases of clinical adverse drug reaction/event induced by gastrodin].

With patients' general situation, medication use, occurrence time of adverse drug reaction/event (ADR/ADE), clinical manifestations and prognosis as reference items, a retrospective study was made for 315 cases with ADR/ADE induced by Gastrodin in Chongqing from January 2008 to June 2014, in order to analyze the characteristics of ADR/ADE and provide reference for rational clinical medication. The results showed that among the 315 cases with ADR/ADE, 143 cases (45.4%) were males and 172 cases (54.6%) were females, most of them (74.9%) were aged above 45; 60 cases (19.0%) with ADE were caused by off-label indications and 66 cases (21.0%) with ADE were caused by over dosage; ADR/ADE cases induced by intravenous drip mainly happened within 30 min (85.5%), ADR/ADE cases induced by oral administration mainly happened within 2 h (74.4%), and all of ADR/ ADE cases induced by intramuscular injection happened within 10 min. Totally 593 ADR/ADE cases were reported, which were mainly damages in gastrointestinal system, skin and its adnexa; And 61.9% of ADR/ADE cases were newly reported. It is suggested that medical workers shall learn about the regularity and characteristics of ADR/ADE induced by gastrodin, apply it in clinic with standards, pay close attention to changes of patients' situations and attach importance to the monitoring of ADR/ADE, so as to enhance the safety of medication.

Analysis of the status of Chinese clinical practice guidelines development.

BACKGROUND: The work of developing clinical practice guidelines began just a little more than ten years ago in China. Up to now, there have been few studies about them. OBJECTIVES: To review and analyze the status of Chinese clinical practice guidelines in 1997-2007. METHODS: All Chinese guidelines from 1997-2007 were collected, and made a regression analysis, and a citation analysis for evaluating the impact of guidelines. To analyze the developing quality, the most influential guidelines were evaluated with AGREE instrument, and each guideline was evaluated to check for any updating. In order to analyze the objective and target population, all guidelines were classified and counted separately according to disease/symptom center, and whether towards specialists or general practitioners. RESULTS: 143 guidelines were collected. An exponential function equation was established for the trend in the number of guidelines. The immediacy index in every year was very low while the average citation rate was not. Both the percentages of highly cited and never cited were high. For the evaluation with AGREE, only the average score of clarity and presentation was high (89.9%); the remaining were much lower. Editorial independence scored 0. Only 27 (18.9%) of 143 guidelines, were found to be evidence-based. Only a few had ever been updated, with an average updating interval of 5.2 years. Only 2.1% were symptom-centered, and only 4.2% were aimed at general practitioners. CONCLUSION: Much progress has been obtained for Chinese guidelines development. However, there were still defects, and greater efforts should be made in the future.

[Roles of axonal transport affected by K141N mutant HSP22 in the pathogenesis of CMT2L].

OBJECTIVE: To compare the axonal transport of wild-type (WT) and K141N mutant HSP22 in transfected primary cultured cortical neurons. METHODS: The plasmid (pCAGGS-HA-wtHSP22 or pCAGGS-HA-K141NHSP22) with WT or K141N mutant HSP22 gene and a GFP-expressing plasmid (pEGFP-N1) were co-transfected respectively into primary cultured cortical neurons. The axonal transport of WT and K141N mutant HSP22 was observed. And the distance traveled by WT and K141N mutant HSP22 was analyzed. RESULTS: The WT HSP22 was transported within axons and uniformly present throughout the entire length of axons. K141N mutant HSP22 failed to be transported to the same extent and was present only in cell body and proximal portion of axons. Analysis of distance traveled revealed that WT HSP22 traveled significantly further than the K141N mutant HSP22. CONCLUSION: The axonal transport of K141N mutant HSP22 may play an important role in the pathogenesis of CMT2L.

Protective effects of quercetin against status epilepticus induced hippocampal neuronal injury in rats: involvement of X-linked inhibitor of apoptosis protein.

Epilepsy is a common neurological disorder affecting people worldwide, and the recurrent spontaneous seizures are often seen post status epilepticus. Apoptosis and necrosis are two forms of neuronal death in post status epilepticus hippocampus, and the former has been widely studied and believed to be a major factor contributing to formation of abnormal excitatory circuit leading to refractory epileptic events. Thus, the need for development of new anti-epileptic agents remains urgent. Quercetin, a plant-derived bioflavonoid, is reported to have neuroprotective effects in neurological disease. We investigated protective effects of quercetin on status epilepticus induced hippocampal neuronal injuries in rats and focused on two major proteins, the X-linked inhibitor of apoptosis protein, a key member of the inhibitor of apoptosis protein family, and the caspase-3 protein, a common effector for the execution-phase of cell signaling apoptotic pathways. The number of apoptotic and surviving neurons were also counted in this study. We found expression alterations of X-linked inhibitor of apoptosis protein and caspase-3 protein in post status epilepticus hippocampus, along with an alteration in the number of apoptotic and surviving neurons. Furthermore, quercetin treatment in rats undergoing status epilepticus led to an interventional effect on expression of X-linked inhibitor of apoptosis protein and the caspase-3 protein, with a corresponding positive change on the number of hippocampal apoptotic and surviving neurons. Together, the study suggests neuroprotective effects of quercetin on hippocampal injury post status epilepticus and the effects may be associated with regulation of the X-linked inhibitor of apoptosis protein and the caspase-3 protein, which can be a decisive factor for apoptosis and survival of neurons in hippocampus.

Perfect Spherical Tetrahedral Metallo-Borospherene Ta4B18 as a Superatom Following the 18-Electron Rule.

Cage-like metallo-borospherenes exhibit unique structures and bonding. Inspired by the newly reported smallest spherical trihedral metallo-borospherene D 3h Ta3B12 - (1), which contains two equivalent B3 triangles interconnected by three B2 units on the cage surface, we present herein a first-principles theory prediction of the perfect spherical tetrahedral metallo-borospherene T d Ta4B18 (2), which possesses four equivalent B3 triangles interconnected by six B atoms, with four equivalent nonacoordinate Ta centers in four η9-B9 rings as integrated parts of the cage surface. As the well-defined global minimum of the neutral, Ta4B18 (2) possesses four 10c-2e B9(π)-Ta(dσ) and eight 10c-2e B9(π)-Ta(dδ) coordination bonds evenly distributed over four Ta-centered Ta@B9 nonagons, with the remaining 18 valence electrons in nine 22c-2e totally delocalized bonds following the 18-electron principle (1S21P61D10) of a superatom. Such a bonding pattern renders spherical aromaticity to the tetrahedral complex, which can be used as building blocks to form the face-centered cubic crystal Ta4B15 (3). The IR, Raman, and UV-vis spectra of Ta4B18 (2) are theoretically simulated to facilitate its future experimental characterizations.

Metal-centered monocyclic carbon wheel clusters with record coordination numbers in planar species.

The highest coordination number identified to date in planar species is CN = 10 in metal-centered monocyclic boron wheel clusters D 10h M©B10 - (M = Ta and Nb) (Galeev et. al., Angew. Chem. Int. Ed., 2012, 51, 2101). Extensive global minimum searches and first-principles theory calculations performed herein indicate that the experimentally observed LaC13 + and LaC14 + possess the well-defined global minima of perfect metal-centered monocyclic carbon wheel D 13h La©C13 + (1) and slightly off-centered C 2v La©C14 + (4) (1A1) with record coordination numbers of CN = 13 and 11 in planar structures, respectively, further pushing the boundary of our understanding of chemical structures and bonding. Detailed molecular orbital, nucleus-independent chemical shift, and ring current analyses indicate that D 13h La©C13 + (1) is σ + π dually aromatic in nature, with 14 totally delocalized in-plane σ electrons and 14 totally delocalized out-of-plane π electrons each matching the 4N + 2 aromatic rule (N σ = N π = 3). Similar σ + π dually aromatic metal-centered monocyclic wheel clusters D 13h Ca©C13 (2), C 13v Ac©C13 + (3), C 2v Y©B6C6 + (5), and C 2v Sc©B5C6 (6) have also been obtained with CN = 13, 13, 12, and 11, respectively. The results obtained in this work effectively enrich the chemical structures and bonding patterns of planar hypercoordinated complexes.

Cage-like La4B24 and Core-Shell La4B290/+/- : perfect spherically aromatic tetrahedral metallo-borospherenes.

Cage-like and core-shell metallo-borospherenes exhibit interesting structures and bonding. Based on extensive global searches and first-principles theory calculations, we predict herein the perfect tetrahedral cage-like Td La4B24 (1) and core-shell Td La4B29 (2), Td La4B29+ (3), and Td La4B29- (4) which all possess the same geometrical symmetry as their carbon fullerene counterpart Td C28, with four equivalent interconnected B6 triangles on the cage surface and four nona-coordinate La centers in four conjoined η9-B9 rings. In these tetra-La-doped boron complexes, La4[B@B4@B24]0/+/- (2/3/4) in the structural motif of 1 + 4 + 28 contain a B-centered tetrahedral Td B@B4 core in a La-decorated tetrahedral La4B24 shell, with the negatively charged tetra-coordinate B- at the center being the boron analog of tetrahedral C in Td CH4 (B- ~ C). Detailed orbital and bonding analyses indicate that these Td lanthanide boride complexes are spherically aromatic in nature with a universal La--B9 (d-p) σ and (d-p) δ coordination bonding pattern. The IR, Raman, and UV-Vis or photoelectron spectra of these novel metallo-borospherenes are computationally simulated to facilitate their spectral characterizations. Graphical abstract.

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.

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.