Extension and Fusion of Cyclic Polyantimony Units.

The synthesis and characterization of a series of polyantimony anionic clusters are reported. The products [(NbCp)2Sb10]2-, [MSb13]3- (M = Ru/Fe), and [MSb15]3- (M = Ru/Fe) were isolated as either K(18-crown-6) or K([2.2.2]-crypt) salts. The Sb10 ring contained in the [(NbCp)2Sb10]2- cluster can be viewed as an extension of two envelope-like cyclo-Sb5 units and represents by far the largest monocyclic all-antimony species. The clusters [MSb13]3- and [MSb15]3- (M = Ru/Fe) illustrate the variability of crown-like Sb8 ring motifs and reveal the fusion of different antimony fragments featuring unique Sb-Sb chain-like units. The reported synthetic approaches involve the fabrication of a variety of distinctive polyantimony anionic clusters, enhancing our understanding of the coordination chemistry of heavier group 15 elements.

Synthesis of Sb688-: Crafting a Homoatomic Antimony Nanotorus.

Pure-element cyclic molecules have garnered extensive attention owing to their intriguing structures and promising applications. Among these, carbon-based cyclic molecules such as cyclo[n]carbon (Cn, n = 10-26) and carbon nanotori have ignited significant interest in both experimental and theoretical investigations. However, systematic investigations of analogous cyclic counterparts of heavier main-group elements are limited, with only a few known by theoretical studies. Furthermore, these corresponding cyclic structures lack synthetic examples in the condensed phase, primarily attributed to their high reactivity resulting from lone electron pairs and the absence of electronic delocalization, which typically aids in stabilizing the structure. In this work, we introduce the pioneering synthesis of a pure antimony-based inorganic nanotorus, denoted as Sb688-, facilitated by the incorporation of C60 for oxidation by utilizing wet-chemistry methodologies. The unique nanotorus structure was meticulously examined via single-crystalline X-ray diffraction, unveiling its composition of 68 antimony atoms and forming a tubular structure with approximate dimensions of 18.5 × 18.4 Å2 in a square shape. Theoretical calculations further revealed that the nanotorus structure, characterized by 16 delocalized electrons distributed across eight 3c-2e σ bonds, effectively saturated the eight two-coordinated Sb atoms within the cluster. This study unveils an innovative approach to synthesizing cyclic compounds solely from pure elements, departing from traditional methods dependent on chemical vapor deposition or surface synthesis, and heralds a profound paradigm shift in physical science.

Camrelizumab plus apatinib in patients with advanced or recurrent endometrial cancer after failure of at least one prior systemic therapy (CAP 04): a single-arm phase II trial.

BACKGROUND: The combination of anti-programmed death 1 (PD-1) inhibitors and tyrosine kinase inhibitors is an effective treatment strategy in endometrial cancer. We aimed to explore the efficacy and safety of camrelizumab plus apatinib as an alternative therapeutic option in patients with previously treated endometrial cancer. METHODS: This single-arm Simon's two-stage phase II trial was conducted at the Fudan University Shanghai Cancer Center. Patients with advanced or recurrent endometrial cancer who had failed at least one prior systemic therapy were screened for potential participation. Eligible patients were treated with intravenous camrelizumab (200 mg d1 q2w) and oral apatinib (250 mg qd) every 4 weeks. The primary end point was the objective response rate (ORR) per RECIST v1.1 in the intention-to-treat principle. RESULTS: Between January 20, 2020, and October 14, 2022, 36 patients (29 with microsatellite stability/mismatch repair proficient [MSS/pMMR] tumors; two with microsatellite instability-high/mismatch repair deficient [MSI-H/dMMR] tumors) were enrolled and treated. The confirmed ORR was 44.4% (95% CI: 27.9, 61.9) and the disease control rate was 91.7% (95% CI: 77.5, 98.2). The median duration of response was 9.3 (95% CI: 4.3, not reached) months, the median progression-free survival was 6.2 (95% CI: 5.3, 11.1) months, and the median overall survival was 21.0 (95% CI: 13.4, not reached) months during a median follow-up of 14.2 (interquartile range: 10.3, 27.6) months. Treatment-related adverse events of grade 3 or 4 occurred in 20 (55.6%) patients, with the most common being increased γ-glutamyl transferase (27.8%), alanine aminotransferase (16.7%) and aspartate aminotransferase (13.9%), and hypertension (11.1%). No treatment-related death occurred. CONCLUSIONS: Camrelizumab plus apatinib showed promising antitumor activity with manageable toxicity in patients with advanced or recurrent endometrial cancer who had failed at least one prior systemic therapy. The findings of this study support further investigation of camrelizumab plus apatinib as an alternative therapeutic option, especially for patients with MSS/pMMR tumors. TRIAL REGISTRATION: This trial was retrospectively registered with ChiCTR.org.cn, number ChiCTR2000031932.

Structures and chemical bonding of B6O50/-/2-: The first boron oxide clusters with five-membered ring and their structural diversity.

Based upon global-minimum searches and first-principles electronic structural calculations, we present the perfectly planar B6O50/-/2- (1-3) systems. Notably, the C2v B6O50/- (1-2) clusters mark a groundbreaking advancement as the first boron oxide clusters to feature a five-membered ring. Both structures exhibit remarkable similarity, each characterized by a central B3O2 ring surrounded by three terminal BO groups. However, a notable difference lies in the bond lengths within the B3O2 core, which are uniform in the former but uneven in the latter. Detailed canonical molecular orbital and AdNDP analyses reveal the delocalized π bonds over the B3O2 ring, affirming the π aromaticity of B6O5-. The Cs B6O52- (3) cluster showcases a chain-like arrangement with three terminal BO groups and a typical OBO group linked to a B2 core, emphasizing the crucial role of electrons in shaping the structure. Detailed chemical bonding analyses reveal the presence of dual three-center four-electron (3c-4e) π hyperbonds in 3, shedding further light on its unique bonding characteristics. Moreover, this study comprehensively extends the B(BO)n0/- (n = 1-5) series and provides valuable perspectives on their structural evolution.

Interaction between XRCC2 gene polymorphism and abdominal obesity on risk of endometrial carcinoma.

AIMS: The aim of this study was to investigate the impact of three single nucleotide polymorphisms (SNPs) within X-Ray Repair Cross Complementary Group 2 (XRCC2) gene and additional gene- abdominal obesity (AO) interaction with endometrial carcinoma (EC) risk. METHODS: Hardy-Weinberg equilibrium was tested for all participants by using SNPstats (online software: http://bioinfo.iconcologia.net/SNPstats). The best SNP-SNP and gene-AO interaction combination among three SNPs within XRCC2 gene and AO was screened using generalized multifactor dimensionality reduction (GMDR). RESULTS: We employed the logistic regression analysis showed that rs718282-T allele is associated with increased EC risk, adjusted ORs (95%CI) were 1.67 (1.23-2.04). However, we did not find statistical association between rs3218536, and rs3218384 and EC susceptibility. GMDR analysis was used for SNP-SNP- and gene-abdominal obesity analysis. The cross-validation consistency and the testing accuracy for the interaction were calculated. The two-locus model between rs718282 and AO had a testing accuracy of 60.11%, which was significant at the p < .001 level, and this two- locus model was considered as the best model. It provided statistical evidence for rs718282 gene-AO interaction effects. The results indicated that AO influenced the EC risk depending on the rs718282 genotypes. Compared with non- AO subjects with rs718282-CC genotype, AO subjects with rs718282-CT or TT genotype had the highest EC risk, OR (95%CI) was 2.83 (1.67 - 4.02), after covariates adjustment. CONCLUSIONS: Both the rs718282- T allele, and its interaction with AO were associated with increased EC risk.

Redox-Controlled Self-Assembly of Vanadium-Seamed Hexameric Pyrogallol[4]Arene Nanocapsules.

Here we report the controlled self-assembly of vanadium-seamed metal-organic nanocapsules with specific metal oxidation state distributions. Three supramolecular assemblies composed of the same numbers of components including 24 metal centers and six pyrogallol[4]arene ligands were constructed: a VIII24L6 capsule, a mixed-valence VIII18VIV6L6 capsule, and a VIV24L6 capsule. Crystallographic studies of the new capsules reveal their remarkable structural complexity and geometries, while marked differences in metal oxidation state distribution greatly affect the photoelectric conversion properties of these assemblies. This work therefore represents a significant step forward in the construction of intricate metal-organic architectures with tailored structure and functionality.

Safety, tolerability, pharmacokinetics, and immunogenicity of JMB2002-an antibody against COVID-19: a phase 1 clinical trial in healthy Chinese adults.

BACKGROUND: The emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and subsequent Coronavirus Disease 2019 (COVID-19) pandemic has resulted in a significant global public health burden, leading to an urgent need for effective therapeutic strategies. Monoclonal antibodies (mAbs) are a potentially effective therapeutic option. We identified a potent antibody JMB2002 against the SARS-CoV-2 receptor binding domain. JMB2002 has demonstrated therapeutic efficacy in a SARS-CoV-2 infected rhesus macaque model. METHODS: We conducted a randomized, double-blind, phase 1 trial to evaluate the JMB2002's safety, tolerability, pharmacokinetics, and immunogenicity in healthy Chinese adults. Participants were randomly assigned to one of four cohorts with sequential dose, administrated intravenously with JMB2002 or placebo, and followed up for 85 ± 5 days. RESULTS: 40 participants were recruited and completed in the study. Eight (25.0%) participants experienced 13 treatment emergent adverse events (TEAEs) that were drug-related. No serious adverse events (SAEs), dose limiting events (DLTs), or adverse events of special interest (AESIs), such as infusion related/allergic reactions, were observed, and no drop out due to adverse events (AEs) occurred. There was no significant safety difference observed between JMB2002 and the placebo, suggesting it was well tolerated. The AUC0-∞, AUC0 - t of JMB2002 infusion increased dose-dependently from 5 mg/kg to 50 mg/kg while there is also a linear trend between doses and Cmax. CONCLUSION: Therefore, JMB2002 was well tolerated after administration of a single dose in the range of 5 mg/kg to 50 mg/kg in healthy Chinese adults. TRIAL REGISTRATION: ChiCTR2100042150 at https://www.chictr.org.cn/searchproj.aspx (14/01/2021).

Anlotinib in patients with recurrent platinum resistant/refractory ovarian cancer: a prospective, single arm, phase II study.

OBJECTIVE: This study aimed to prospectively evaluate the efficacy and safety of anlotinib in patients with platinum resistant/refractory ovarian cancer. METHODS: In this prospective, single arm, phase II study, patients with platinum resistant/refractory ovarian cancer received anlotinib (12 mg once daily; days 1-14; 21 days per cycle) until disease progression, unacceptable toxicity, or study withdrawal. The study was conducted between May 2019 and May 2021. The primary endpoint was objective response rate. Secondary endpoints were disease control rate, progression free survival, overall survival, and safety. An exploratory biomarker analysis was performed to evaluate the correlation of baseline TP53 mutation status with outcomes. RESULTS: 33 of 34 enrolled patients received at least one dose of anlotinib. The objective response rate was 31.2% (95% confidence interval (CI) 16.1% to 50.0%), with 2 (6.3%) complete and 8 (25.0%) partial responses. In total, 14 (43.8%) patients achieved stable disease, resulting in a disease control rate of 75.0% (95% CI 56.6% to 88.5%). With a median follow-up of 4.6 months (range 0.5-17.2) at data cut-off (September 16, 2022), median progression free survival was 5.3 months (95% CI 4.04 to 6.56) and median overall survival was not reached. In a subgroup analysis, patients with a TP53 mutation showed a trend towards worse progression free survival than those with the wild-type TP53 (4.4 months vs 8.4 months; hazard ratio 2.48 (95% CI 0.91 to 6.76), p=0.067). Common adverse events were hypertension (42.4%), hand-foot syndrome (27.3%), and fatigue (24.2%). Grade 3 events were reported in 3 (9.1%) patients and no grade 4-5 events or deaths were observed. CONCLUSION: Anlotinib showed antitumor activity with an acceptable safety profile in patients with platinum resistant/refractory ovarian cancer, and it might be a potential treatment in this population.

Serum exosomal proteomics analysis of lung adenocarcinoma to discover new tumor markers.

BACKGROUND: Among the most aggressive and rapidly lethal types of lung cancer, lung adenocarcinoma is the most common type. Exosomes, as a hot area, play an influential role in cancer. By using proteomics analysis, we aimed to identify potential markers of lung adenocarcinoma in serum. METHODS: In our study, we used the ultracentrifugation method to isolate serum exosomes. The Liquid chromatography-mass spectrometry (LC-MS) and bioinformatics analysis were used to identify potential serum exosomal proteins with altered expression among patients with advanced lung adenocarcinoma, early lung adenocarcinoma, and healthy controls. A western blot (WB) was performed to confirm the above differential expression levels in a separate serum sample-isolated exosome, and immunohistochemistry (IHC) staining was conducted to detect expression levels of the above differential proteins of serum exosomes in lung adenocarcinoma tissues and adjacent tissues. Furthermore, we compared different expression models of the above differential proteins in serum and exosomes. RESULT: According to the ITGAM (Integrin alpha M chain) and CLU (Clusterin) were differentially expressed in serum exosomes among different groups as well as tumor tissues and adjacent tissues. ITGAM was significantly and specifically enriched in exosomes. As compared to serum, CLU did not appear to be significantly enriched in exosomes. ITGAM and CLU were identified as serum exosomal protein markers of lung adenocarcinoma. CONCLUSIONS: This study can provide novel ideas and a research basis for targeting lung adenocarcinoma treatment as a preliminary study.

Secondary cytoreduction followed by chemotherapy versus chemotherapy alone in platinum-sensitive relapsed ovarian cancer (SOC-1): a multicentre, open-label, randomised, phase 3 trial.

BACKGROUND: The benefits of secondary cytoreduction for platinum-sensitive relapsed ovarian cancer are still widely debated. We aimed to assess the efficacy of secondary cytoreduction plus chemotherapy versus chemotherapy alone in this patient population. METHODS: This multicentre, open-label, randomised, controlled, phase 3 trial (SOC-1), was done in four primarily academic centres in China (two in Shanghai, one in Hangzhou, and one in Guangzhou). Eligible patients were women aged 18 years and older with platinum-sensitive relapsed epithelial ovarian cancer with a platinum-free interval of at least 6 months after the end of first-line platinum-based chemotherapy and were predicted to have potentially resectable disease according to the international model (iMODEL) score and PET-CT imaging. iMODEL score was calculated using six variables: International Federation of Gynecology and Obstetrics stage, residual disease after primary surgery, platinum-free interval, Eastern Cooperative Oncology Group performance status, serum level of cancer antigen 125 at recurrence, and presence of ascites at recurrence. An iMODEL score of 4·7 or lower predicted a potentially complete resection. As per a protocol amendment, patients with an iMODEL score of more than 4·7 could only be included if the serum level of cancer antigen 125 was more than 105 U/mL, but the principal investigators assessed the disease to be resectable by PET-CT. Eligible participants were randomly assigned (1:1) via a permuted block design (block size of six) and stratified by study centre, iMODEL score, residual disease at primary surgery, and enrolment in the Shanghai Gynecologic Oncology Group SUNNY trial, to undergo secondary cytoreductive surgery followed by intravenous chemotherapy (six 3-weekly cycles of intravenous paclitaxel [175 mg/m2] or docetaxel [75 mg/m2] combined with intravenous carboplatin [area under the curve of 5 mg/mL per min]; surgery group) or intravenous chemotherapy alone (no surgery group). Primary endpoints were progression-free survival and overall survival, analysed in all participants randomly assigned to treatment, regardless of treatment received (intention-to-treat [ITT] population). Here, we report the final analysis of progression-free survival and the prespecified interim analysis of overall survival. Safety was assessed in all participants who received their assigned treatment and had available adverse event data. This study is registered with ClinicalTrials.gov, NCT01611766, and is ongoing but closed to accrual. FINDINGS: Between July 19, 2012, and June 3, 2019, 357 patients were recruited and randomly assigned to the surgery group (182) or the no surgery group (175; ITT population). Median follow-up was 36·0 months (IQR 18·1-58·3). In the no surgery group, 11 (6%) of 175 participants had secondary cytoreduction during second-line therapy while 48 (37%) of 130 participants who had disease progression crossed-over and had surgery at a subsequent recurrence. Median progression-free survival was 17·4 months (95% CI 15·0-19·8) in the surgery group and 11·9 months (10·0-13·8) in the no surgery group (hazard ratio [HR] 0·58; 95% CI 0·45-0·74; p<0·0001). At the interim overall survival analysis, median overall survival was 58·1 months (95% CI not estimable to not estimable) in the surgery group and 53·9 months (42·2-65·5) in the no surgery group (HR 0·82, 95% CI 0·57-1·19). In the safety population, nine (5%) of 172 patients in the surgery group had grade 3-4 surgical morbidity at 30 days, and no patients in either group had died at 60 days after receiving assigned treatment. The most common grade 3-4 adverse events during chemotherapy were neutropenia (29 [17%] of 166 patients in the surgery group vs 19 [12%] of 156 patients in the no surgery group), leucopenia (14 [8%] vs eight [5%]), and anaemia (ten [6%] vs nine [6%]). Four serious adverse events occurred, all in the surgery group. No treatment-related deaths occurred in either group. INTERPRETATION: Secondary cytoreduction followed by chemotherapy was associated with significantly longer progression-free survival than was chemotherapy alone in patients with platinum-sensitive relapsed ovarian cancer, and patients should be counselled about the option of secondary cytoreduction in specialised centres. Long-term survival outcomes will be assessed using mature data on overall survival. FUNDING: Zhongshan Development Program. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Promoter Methylation-mediated Silencing of the MiR-192-5p Promotes Endometrial Cancer Progression by Targeting ALX1.

Background: Epigenetic regulation by promoter methylation-mediated silencing of cancer-related microRNAs plays vital roles in tumorigenesis. MiR-192-5p promotes tumor progression in various human cancers with conflicting biological effects. However, its expression levels and biological functions in endometrial carcinoma (EC) have not been reported. Methods: The methylation status of miR-192-5p in tissue samples and cell lines, was examined using bisulfite sequencing PCR. miR-192-5p expression was also measured. EC cell lines transfected with specifically designed vectors overexpressing miR-192-5p, its target gene ALX1 or both, were constructed. Tumorigenicity of these cell lines were examined by in vitro and in vivo experiments. Dual-luciferase reporter assay were employed to verify the target of miR-192-5p. Results: The promoter region of miR-192-5p gene was highly methylated and its expression significantly repressed in EC samples. Moreover, a higher level of promoter methylation as well as a lower expression of miR-192-5p, was significantly associated with advanced Federation of Gynecology and Obstetrics stage and shorter disease-free survival in patients with curatively resected EC. Functional studies demonstrated that miR-192-5p overexpression inhibited in vitro tumor progression, in vivo tumorigenicity and the expression of several oncoproteins that was highly related to epithelial-to-mesenchymal transition. ALX1 was verified as a direct target of miR-192-5p and demonstrated to mediate the tumor-suppressive function of miR-192-5p. Conclusion: miR-192-5p is a tumor suppressor miRNA that is epigenetically silenced by promoter methylation and may serve as a potential prognostic biomarker in EC.

A preoperative prediction model for predicting coexisting adnexa malignancy of patients with G1/G2 endometrioid endometrial cancer.

OBJECTIVE: To identify the predictors of coexisting adnexa malignancy (CAM) before surgery for patients with G1/G2 endometrioid endometrial cancer (EEC). METHODS: Patients with G1/G2 EEC who received surgery in Fudan University Shanghai Cancer Center from 1996 to 2017 were enrolled. Univariate and multivariate logistic regression were performed to identify the predictors for CAM, and the nomogram was constructed and evaluated the discrimination and calibration. RESULTS: Among the 1511 patients in the study cohort, 66 (4.4%) coexisted adnexa malignancy (51 metastatic and 15 synchronous primaries). In the univariate logistic regression analysis, CA125 level (>35 U/ml), histologic grades, myometrial invasion depth in magnetic resonance imaging (MRI), adnexal involvement in MRI/surgical exploration (SEP) were found to be significant predictors for CAM (P < .001, 0.047, 0.011, <0.001, respectively). The multivariate analysis demonstrated that high CA125 level (P < .001; OR: 2.945; 95%CI: 1.700-5.101), deep myometrial invasion (P = .011; OR: 2.194; 95%CI: 1.200-4.011), and suspected adnexal involvement in MRI/SEP (P < .001; OR: 11.524; 95%CI: 6.726-19.744) were independent predictors for CAM (AUC = 0.786). In 338 patients with MMR results, eighty-seven (25.7%) were detected MSI-high. There were 5.7% (5/87) patients diagnosed with CAM in the MSI-high group compared with 4.4% (11/251) in the MSS group. CONCLUSIONS: A nomogram with pre- and intra-operative factors was constructed to predict CAM in G1/G2 EEC patients, which may help clinicians in decision-making for ovarian preservation for these patients.

Screening for hereditary cancers in patients with endometrial cancer reveals a high frequency of germline mutations in cancer predisposition genes.

As inherited genetic alterations are important etiological factors causing endometrial cancer (EC), our study aimed to outline the ethnic-related prevalence and the associated clinical and biological characteristics of germline mutations in cancer predisposition genes in Chinese EC patients. One hundred ninety-eight Chinese EC patients were screened for germline mutations in a panel of cancer susceptibility genes using next-generation sequencing combined with multiplex ligation-dependent probe amplification. First, we found that among patients under 50 years of age, 26% (18/69) carried germline genetic mutations, all involving mismatch repair (MMR) genes except for one mutation affecting BRCA1. Second, when we focused on Lynch syndrome (LS) with additional selected patients, 45 were identified to carry pathogenic mutations in MMR genes, with a higher frequency found in MSH2 and MSH6. We found that age at onset, personal and familial history together with immunohistochemical assay results were the most useful criteria for the diagnosis of LS although limitations in routine practice and the sensitivity and specificity of each parameter should be taken into account. One pathogenic mutation in the PALB2 gene was detected in a patient with no breast cancer in her family. Interestingly, we identified a family carrying pathogenic variant in both PMS2 and BRCA1 genes with distinct clinical phenotypes. Multigene panel testing should be recommended to patients based on their clinical information and tumor phenotype. Our study also showed the genetic complexity in EC, which requires further investigations.

A photoelectron spectroscopy and quantum chemical study on ternary Al-B-O clusters: AlnBO2- and AlnBO2 (n = 2, 3).

Both B and Al have high oxygen affinity and their oxidation processes are highly exothermic, hinting at intriguing physical chemistry in ternary Al-B-O clusters. We report a combined photoelectron spectroscopy and density-functional study on the structural, electronic, and bonding properties of AlnBO2- and AlnBO2 (n = 2, 3) clusters. Ground-state vertical detachment energies (VDEs) are measured to be 2.83 and 2.24 eV for Al2BO2- and Al3BO2-, respectively. A weak isomer is also observed for Al3BO2- with a VDE of 1.31 eV. Coalescence-kick global searches allow the identification of candidate structures, confirmed via comparisons with experiment. The Al2BO2- anion is V-shaped in geometry, Cs (1A'), with an Al center connecting to OB and OAl terminals. It can be viewed alternatively as the fusion of BOAl and AlOAl by sharing an Al atom. Al3BO2- has a Cs (2A'') global minimum in which an Al2 dimer interacts with bridging boronyl (BO) and an OAl unit, as well as a low-lying C2v (2B2) isomer consisting of boronyl and OAl that are doubly bridged by two Al atoms. The BO2 block (linear O[double bond, length as m-dash]B[double bond, length as m-dash]O chain) is nonexistent in any of the anion and neutral species. Chemical bonding in these Al-B-O clusters is elucidated via canonical molecular orbitals and adaptive natural density partitioning. The cluster structures are also rationalized using the concept of sequential and competitive oxidation of B versus Al centers in AlnB. The first O atom prefers to oxidize B and form BO, whereas the second O atom has options to interact with a fresh Al/Aln/AlnB unit or a BO group. The former route wins thermodynamically, leading to the observed geometries.

Planar Tricyclic B8O8 and B8O8- Clusters: Boron Oxide Analogues of s-Indacene C12H8.

Boron clusters and their oxides are electron-deficient species with (π and σ) aromaticity and antiaromaticity, enabling a structural and bonding analogy between them and the aromatic hydrocarbons. s-Indacene C12H8 is normally considered as a border system between the classes of aromatic and antiaromatic hydrocarbons. We show herein, via computer global-minimum searches and B3LYP and single-point CCSD(T) calculations, that boron oxide clusters D2h B8O8 (1, 1Ag) and D2h B8O8- (2, 2B2g) adopt planar tricyclic structures, which feature fused heterocyclic B3O2/B4O2/B3O2 rings and two boronyl (BO) terminals, a structural pattern analogous to the C5/C6/C5 rings in s-indacene. Bonding analyses indicate that B8O8 (1) is a formally antiaromatic 12π system, the molecular orbitals of which are largely similar to those of s-indacene. Infrared and ultraviolet-visible spectra of B8O8 (1) neutral, as well as the photoelectron spectrum of B8O8- (2) anion, are predicted computationally. The latter spectrum shows a sizable energy gap of 3.5 eV for 2, demonstrating the electronic robustness of 1. Our bonding analyses also shed critical light on the nature of bonding in s-indacene.

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.

Endohedral charge-transfer complex Ca@B37(-): stabilization of a B37(3-) borospherene trianion by metal-encapsulation.

Based on extensive first-principles theory calculations, we present the possibility of an endohedral charge-transfer complex, Cs Ca@B37(-) (), which contains a 3D aromatic fullerene-like Cs B37(3-) () trianion composed of interwoven boron double chains with twelve delocalized multicenter π bonds (12 mc-2e π, m = 5, 6) over a σ skeleton, completing the Bn(q) borospherene family (q = n - 40) in the size range of n = 36-42.

On the nature of chemical bonding in the all-metal aromatic [Sb3Au3Sb3](3-) sandwich complex.

In a recent communication, an all-metal aromatic sandwich [Sb3Au3Sb3](3-) was synthesized and characterized. We report herein a density-functional theory (DFT) study on the chemical bonding of this unique cluster, which makes use of a number of computational tools, including the canonical molecular orbital (CMO), adaptive natural density partitioning (AdNDP), Wiberg bond index, and orbital composition analyses. The 24-electron, triangular prismatic sandwich is intrinsically electron-deficient, being held together via six Sb-Sb, three Au-Au, and six Sb-Au links. A standard, qualitative bonding analysis suggests that all CMOs are primarily located on the three Sb3/Au3/Sb3 layers, three Au 6s based CMOs are fully occupied, and the three extra charges are equally shared by the two cyclo-Sb3 ligands. This bonding picture is referred to as the zeroth order model, in which the cluster can be formally formulated as [Sb3(1.5+)Au3(3-)Sb3(1.5+)](3-) or [Sb3(0)Au3(3-)Sb3(0)]. However, the system is far more complex and covalent than the above picture. Seventeen CMOs out of 33 in total involve remarkable Sb → Au electron donation and Sb ← Au back-donation, which are characteristic of covalent bonding and effectively redistribute electrons from the Sb3 and Au3 layers to the interlayer edges. This effect collectively leads to three Sb-Au-Sb three-center two-electron (3c-2e) σ bonds as revealed in the AdNDP analyses, despite the fact that not a single such bond can be identified from the CMOs. Orbital composition analyses for the 17 CMOs allow a quantitative understanding of how electron donation and back-donation redistribute the charges within the system from the formal Sb3(0)/Au3(3-) charge states in the zeroth order model to the effective Sb3(1.5-)/Au3(0) charge states, the latter being revealed from the natural bond orbital analysis.

Saturn-like charge-transfer complexes Li4&B36, Li5&B36⁺, and Li6&B36²âº: exohedral metalloborospherenes with a perfect cage-like B364⁻ core.

Based on extensive first-principles theory calculations, we present the possibility of construction of the Saturn-like charge-transfer complexes Li4&B36 (2), Li5&B36(+) (3), and Li6&B36(2+) (4) all of which contain a perfect cage-like B36(4-) (1) core composed of twelve interwoven boron double chains with a σ + π double delocalization bonding pattern, extending the Bn(q) borospherene family from n = 38-42 to n = 36 with the highest symmetry of T(h).

Star-like superalkali cations featuring planar pentacoordinate carbon.

Superalkali cations, known to possess low vertical electron affinities (VEAs), high vertical detachment energies, and large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps, are intriguing chemical species. Thermodynamically, such species need to be the global minima in order to serve as the promising targets for experimental realization. In this work, we propose the strategies of polyhalogenation and polyalkalination for designing the superalkali cations. By applying these strategies, the local-minimum planar pentacoordinate carbon (ppC) cluster CBe5 can be modified to form a series of star-like superalkali ppC or quasi-ppC CBe5X5 (+) (X = F, Cl, Br, Li, Na, K) cations containing a CBe5 moiety. Polyhalogenation and polyalkalination on the CBe5 unit may help eliminate the high reactivity of bare CBe5 molecule by covering the reactive Be atoms with noble halogen anions and alkali cations. Computational exploration of the potential energy surfaces reveals that the star-like ppC or quasi-ppC CBe5X5 (+) (X = F, Cl, Br, Li, Na, K) clusters are the true global minima of the systems. The predicted VEAs for CBe5X5 (+) range from 3.01 to 3.71 eV for X = F, Cl, Br and 2.12-2.51 eV for X = Li, Na, K, being below the lower bound of the atomic ionization potential of 3.89 eV in the periodic table. Large HOMO-LUMO energy gaps are also revealed for the species: 10.76-11.07 eV for X = F, Cl, Br and 4.99-6.91 eV for X = Li, Na, K. These designer clusters represent the first series of superalkali cations with a ppC center. Bonding analyses show five Be-X-Be three-center two-electron (3c-2e) σ bonds for the peripheral bonding, whereas the central C atom is associated with one 6c-2e π bond and three 6c-2e σ bonds, rendering (π and σ) double aromaticity. Born-Oppenheimer molecular dynamics simulations indicate that the CBe5 motif is robust in the clusters. As planar hypercoordination carbon species are often thermodynamically unstable and highly reactive, the superalkali cation characters of these ppC species should be highlighted, which may be suitable for experimental realization.