PubMed Health⌕ Search

Biomedical subjects

Lei Han

Publications and source records attributed to Lei Han.

At least 19 recordsLinked to original sources

A Molecularly Anchored Spatial Transcriptomic Framework for Precise CA1-Subiculum Parcellation and Region-Resolved Analysis in Alzheimer's Disease.

BACKGROUND: The precise molecular delineation of the interface between the Subiculum (Sub) and cornu ammonis 1 (CA1) is a challenge in hippocampal research, as conventional cytoarchitectural boundaries are often ambiguous and limit reproducible regional annotation. Here, we developed a molecularly anchored spatial transcriptomic framework to define CA1-Sub regional identities using high-definition spatial transcriptomics (Stereo-seq) and single-nucleus RNA sequencing (snRNA-seq) references. FINDINGS: Using a human hippocampal Stereo-seq dataset from 12 donors, we established a data-driven parcellation framework that defines reproducible molecular features distinguishing CA1 and Sub while capturing the transition between these regions. FN1 was identified as a Sub-enriched marker in a subset of EX_Sub and, together with ETV1 and additional regional markers, enabled molecular assignment of CA1 and Sub identities across datasets. The Sub association of FN1 and ETV1 was further supported by human 10X Genomics spatial transcriptomics, mouse in situ hybridization data, and a mouse spatial transcriptomic dataset. Applying this framework to Alzheimer's disease (AD) tissues revealed region-specific transcriptional alterations across CA1 and Sub, including enrichment of mitochondrial energy metabolism-related transcripts in the Sub, suggesting exploratory transcriptional associations of altered metabolic function. CONCLUSIONS: This study provides a molecularly anchored framework for human CA1-Sub parcellation that complements conventional annotation. By defining regional molecular states while preserving the biological continuum across CA1-Sub interface, this approach enables more consistent regional analysis of human hippocampus tissue across donors, datasets, and disease conditions.

Journal Article↗

Schisantherin B mitigates cisplatin-induced ototoxicity by modulating the CNPY2-PERK/CHOP signaling axis.

Irreversible cisplatin-induced hearing loss (CIHL) is a refractory chemotherapy-related adverse effect with limited clinical treatments. Schisantherin B (STB), a lignan isolated from Schisandra chinensis, is widely recognized for its neuroprotective properties, while its role in auditory injury remains unclear. Herein, we found that STB alleviated cisplatin-induced ototoxicity in House Ear Institute Organ of Corti 1 (HEI-OC1) cells and guinea pig models, protecting cochlear hair cells, synaptic ribbons and spiral ganglion neurons, and partially restoring auditory brainstem response (ABR) thresholds. Furthermore, combined drug affinity responsive target stability (DARTS) assay, the cellular thermal shift assay (CETSA), and the surface plasmon resonance (SPR) assay, we confirmed STB directly binds to the canopy FGF signaling regulator 2 (CNPY2), a key initiator of endoplasmic reticulum (ER) stress. Notably, consistent dual in vitro and in vivo validation confirmed that STB exerts no regulatory effect on CNPY2 protein abundance, yet suppressed the downstream Protein kinase R-like endoplasmic reticulum kinase / C/EBP homologous protein (PERK/CHOP) signaling cascade and ER stress-mediated apoptosis. Moreover, molecular docking and co-immunoprecipitation (co-IP) validated the physical binding of STB to CNPY2 and the endogenous interaction between CNPY2 and PERK. Additionally, CNPY2 overexpression and shRNA knockdown further verified this functional relationship. Integrated proteomic and transcriptomic analyses showed STB partially reversed cisplatin-triggered inflammation and excessive ER stress. Collectively, our results suggest STB may serve as a potential otoprotective agent. The CNPY2-PERK/CHOP axis is closely linked to cisplatin-induced cochlear damage and offers a feasible target for intervention against CIHL. Abbreviations: CIHL, cisplatin-induced hearing loss; STB, Schisantherin B; HEI-OC1, house ear institute organ of corti 1; ABR, auditory brainstem response; DARTS, drug affinity responsive target stability; CETSA, cellular thermal shift assay; SPR, surface plasmon resonance; CNPY2, canopy FGF signaling regulator 2; ER, endoplasmic reticulum; PERK, protein kinase R-like endoplasmic reticulum kinase; CHOP, C/EBP homologous protein; co-IP, co-immunoprecipitation; STA, Schisantherin A; STC, Schisantherin C; dB SPL, decibels sound pressure level; EDTA, ethylenediaminetetraacetic acid; dB SPL, decibels sound pressure level; SGN, spiral ganglion neuron; IHCs, inner hair cells; OHCs, outer hair cells; CCK-8, Cell Counting Kit-8; OD, optical density; ODb, blank sample, ODc, control sample; NC, negative control; PVDF, polyvinylidene difluoride; RT, room temperature; LC-MS/MS, liquid chromatography tandem mass spectrometry; MS, mass spectrometry; DMSO, dimethyl sulfoxide; KDs, equilibrium dissociation constants; SP, standard precision; SEM, standard error of the mean; HSD, honestly significant difference; Ctrl, control group; CV, cell viability; Kd, dissociation rate constant; Ka, association rate constant; STS, sodium thiosulfate; UPR, unfolded protein response; BLB, blood-labyrinth barrier.

Apoptosis↗

Full-length single-cell spatial transcriptomics reveals spatial and cell-type-specific transcript isoforms in the primate brain.

The primate brain exhibits complex RNA alternative splicing heterogeneity crucial for functional complexity, yet systematic spatial isoform characterization has been lacking. We developed Fullscope-seq, a full-length single-molecule large field-of-view spatial transcriptomics sequencing method at single-cell resolution, based on programmed concatenation cDNA for multiple long-read sequencing platforms. Applying Fullscope-seq to the macaque brain, we uncovered thousands of genes exhibiting differential transcript usage (DTU) across cortical layers, cell types and brain regions. Fullscope-seq resolved hundreds of major isoform switches across distinct brain regions and identified DTUs between superficial and deep cortical layers. Cortical layer-specific DTUs showed cell-composition dependence, whereas regional DTUs were regulated according to both cellular composition and spatial contexts. These isoform variations showed substantial enrichment for neuropsychiatric disorder-associated genes and were conserved across platforms and species. Our study establishes a scalable framework for spatial isoform analysis and provides a resource for understanding transcriptomic diversity in complex tissues.

Animals↗

LncRNA HAR1A in triple-negative breast cancer: mechanisms and the role of polymorphism rs 6089838 in susceptibility.

BACKGROUND: Long non-coding RNAs (lncRNAs) are increasingly recognized as crucial regulators and potential biomarkers in triple-negative breast cancer (TNBC). This study examined the link between the rs6089838 polymorphism in HAR1A and TNBC susceptibility/progression and function. RESEARCH DESIGN AND METHODS: 197 TNBC patients and 185&#xa0;healthy controls were recruited. Rs6089838 genotyping and serum lncRNA HAR1A quantification were performed using qRT PCR. Survival was analyzed via KM and Cox regression.. Cellular proliferation, migration, and invasion were measured using CCK-8 and Transwell assays. RESULTS: The GG genotype significantly lowered TNBC risk versus the AA genotype (OR =0.393, p&#x2009;=&#x2009;0.002). GA/GG genotypes were associated with more favorable clinicopathological features. Serum lncRNA HAR1A was downregulated in TNBC patients (p&#x2009;<&#x2009;0.001) and was positively correlated with the protective G allele frequency (p&#x2009;<&#x2009;0.001). GA/GG carriers showed significantly longer overall survival than AA homozygotes (p&#x2009;<&#x2009;0.001). Functional studies confirmed that HAR1A overexpression via pcDNA3.1 suppressed proliferation, migration, and invasion in breast cancer cell lines. Conversely, siRNA-mediated lncRNA HAR1A knockdown enhanced these oncogenic traits. CONCLUSION: The G allele of HAR1A rs6089838 represents a protective variant against TNBC susceptibility and progression, likely through HAR1A's tumor-suppressive activity. This SNP may have potential as a biomarker for TNBC risk and prognosis assessment.

Humans↗

The application of AI-driven and engineered intratumoral microbes in cancer therapy.

BACKGROUND: Although investigations of the intratumoral microbiota date back thousands of years, breakthrough transformations have only recently been achieved through high-throughput sequencing and multiomic technologies. These advances have revealed diverse and tumor type-specific microbial communities that drive carcinogenesis via immunomodulation, metabolic reprogramming, and genomic instability. Current cornerstones of cancer therapies-including chemotherapy, radiotherapy, immunotherapy, and targeted therapy-are limited by systemic toxicity, localized tissue damage, drug resistance, and low patient response rates. These constraints underscore the urgent need for more effective and precise therapeutic strategies. MAIN BODY: This review comprehensively integrates artificial intelligence (AI) technologies into the characterization of the intratumoral microbiota, facilitating the development of novel computational pipelines for mapping microbe-host crosstalk. We systematically summarize recent advances in engineered microbial therapeutics, including bacteria designed for targeted antitumor activity and engineered microorganisms that enable the localized delivery of therapeutic agents. Furthermore, this review critically evaluates the safety profiles of microbiota-based interventions and discusses key challenges in clinical translation. CONCLUSIONS: By combining cutting-edge computational technologies, biological research, and clinical insights, this review aims to bridge the gap between microbiome science and oncological practice, pioneering innovative strategies for microbiota-guided diagnostics and personalized cancer therapy.

Humans↗

Role of anti-nucleosome antibody in the diagnosis of systemic lupus erythematosus.

OBJECTIVE: To investigate the role of anti-nucleosome antibodies (AnuA) in systemic lupus erythematosus (SLE). METHODS: IgG anti-nucleosome antibodies were detected by enzyme-linked immunosorbent assay (ELISA) in the sera of 233 SLE and 220 other rheumatic diseases' patients as well as 31 health controls. The patients were also evaluated for clinical and biological parameters. RESULTS: (1) Out of 233 SLE patients, 144 (61.8%) were seropositive for AnuA, which was significantly higher than that of patients with other rheumatic diseases [2.7% (6/220), P < 0.001]; the sensitivities and specificities of AnuA in SLE were 61.8% and 97.6%, respectively. (2) The positive rated of AnuA in SLE lacking of anti-DNP, anti-cmDNA, anti-Sm and anti-dsDNA antibodies were 57.1%, 55.9%, 62.4% and 51.2%, respectively. (3) The frequency of the fever, skin rash, and arthralgia were significantly higher in 144 positive AnuA SLE than those in AnuA negative SLE (P < 0.05). The frequency of leukopenia, elevations of ESR and CRP, lower C3/C4 levels and proteinuria in AnuA positive groups was significantly higher than that of AnuA negative groups (P < 0.05). (4) Level of AnuA was strongly correlated with the SLEDAI scores (r = 0.385, P < 0.001). Patients with active SLE showed significantly higher positive rate of AnuA (66.1%) than those with inactive disease (45.7%) (chi2 = 6.568, P = 0.010). CONCLUSIONS: AnuA is one of the most valuable markers in the diagnosis of SLE lacking of anti-dsDNA, anti-Sm, anti-DNP and anti-cmDNA antibodies. The level of AnuA is associated with the disease activity of SLE.

Adolescent↗

Two-dimensional indium sulfide framework constructed from pentasupertetrahedral p1 and supertetrahedral t2 clusters.

A new open-framework indium sulfide ([In12S24H2]10-) constructed from pentasupertetrahedral sulfide clusters ([In8S17H],9- P1) and supertetrahedral sulfide clusters ([In4S10H],7-) T2) has been prepared through hydrothermal synthesis. Unlike previously reported P1 clusters that require divalent metal cations, the P1 cluster reported here consists of only trivalent ions (In3+) and is the only known example of tetrahedral clusters with a core sulfur site bonded to four trivalent ions. Each P1 cluster is joined to three T2 clusters (vice versa) to form an infinite two-dimensional sheet stacked along the crystallographic c-axis. In contrast with known three-dimensional open-framework indium sulfides in which locations of extraframework amines are rarely known due to disorder, structure-directing amine molecules are much less disordered as a result of host-guest N-H...S hydrogen bonding. The UV-vis diffuse reflectance spectrum shows that this material is a wide band gap semiconductor.

Crystallography, X-Ray↗

[Therapeutic effect and impact on cytokine production by methotrexate in rheumatoid arthritis].

OBJECTIVE: To examine the clinical benefit and impact on cytokine production by methotrexate in rheumatoid arthritis. METHODS: Thirty patients with RA were treated with oral methotrexate (mean, 15 mg per week) as monotherapy for 24 weeks. Clinical assessment using the American College of Rheumatology (ACR) criteria for improvement was performed at baseline and at the end of 2, 4, 8, 12 and 24 weeks. The pro-inflammation cytokine TNF-alpha, INF-gamma,IL-1beta, IL-6 and anti-inflammation cytokine IL-10 were measured in RA sera at baseline and after 24 weeks of therapy. RESULTS: There was remarkable improvement in disease activity following the MTX treatment. At the end of 24 weeks, the percent age of ACR20 was 70% (21/30), ACR50 30% (9/30) and ACR70 10% (3/30). The levels of IL-6 (46.83+/-35.81 vs. 20.92+/-17.98, P=0.001), TNF-alpha (162.52+/-107.63 vs. 18.32+/-14.36, P=0.026) and INF-gamma (67.79+/-43.76 vs. 35.78+/-27.51, P=0.004) were significantly higher than those of the health control at baseline, respectively. The levels of TNF-alpha (123.36+/-89.61,P=0.018), INF-gamma (41.53+/-13.49, P=0.015), IL-1beta (7.47+/-7.33, P=0.026), IL-6 (26.01+/-25.64, P=0.025) were significantly decreased after treatment with methotrexate. In contrast, IL-10 was remarkably increased (71.76+/-41.01, P=0.02). CONCLUSION: Methotrexate is effective in patients with rheumatoid arthritis. It can suppress the symptoms and joint damage. In addition, methotrexate treatment decreases the levels of pro-inflammatory cytokine, and increases the level of anti-inflammatory cytokine.

Adult↗

Solvothermal in situ ligand synthesis through disulfide cleavage: 3D (3,4)-connected and 2D square-grid-type coordination polymers.

Two novel coordination polymers, Cu3(4-pyt)3 (1) and Co(4-pyt)2 (2) (4-pyt = pyridine-4-thiolate), have been synthesized by in situ generation of a 4-pyt ligand from a 4,4'-dithiodipyridine precursor through reductive cleavage of the disulfide bond under solvothermal conditions. 1 and 2 exhibit a three-dimensional (3,4)-connected network and a two-dimensional square-grid-type structure, respectively.

Chemistry, Inorganic↗

Genetic analysis and histological study of red seed in rice.

Reciprocal crosses between red and achromatic rice revealed that the seed color of F1 was determined by its female parent. According to the seed color and plant segregation ratio of F1, F2, and F3 generations, the red phenotype of red double-haploid seed was determined by a dominant, monogene with maternal effect. Histological study showed that the red pigments accumulated in the pericarp layer only. The assay of developmental timing of pigment accumulation showed that the red color accumulated from desiccation stage to perfectly maturation stage of the seeds.

DNA, Plant↗

Genetic analysis and gene mapping of purple stigma in rice.

A new double-haploid (rdh) rice plant with purple stigma and red seeds was discovered by tissue culture. Genetic analysis suggested that the trait of rdh purple stigma was controlled by a pair of dominant gene. Polymorphic analysis of microsatellite markers demonstrated that the purple stigma gene of rdh was located on rice chromosome 6 at 4.2 cM, 0.35 cM and 0.53 cM from microsatellite markers RM276, RM253 and RM111, respectively. It was believed that the purple stigma gene of rdh was the first mapped purple stigma gene on rice chromosome 6. This purple stigma gene was designated tentatively as Ps-4.

Chromosome Mapping↗

Lack of HIV testing and awareness of HIV infection among men who have sex with men, Beijing, China.

In China, men who have sex with men (MSM) are at high risk for HIV. However, little is known about their HIV testing behavior. From September 2001 to January 2002, we recruited 482 men through social networks and MSM venues. We conducted HIV testing and counseling, and anonymous, standardized face-to-face interviews. Eighty-two percent of participants had never tested for HIV before the study. The most common reasons for not testing were perceived low risk of HIV infection (72%), not knowing the location of test sites (56%), fear of positive test results (54%), fear of people learning about his homosexuality (47%), and fear of breach of confidentiality about test results (47%). We identified five statistically significant independent correlates of having been tested for HIV: being older, having a college degree, being more "out" (disclosing MSM activities to people), being recruited through social networks, and having a lifetime history of sexually transmitted diseases. Of 15 participants (3.1%) who tested positive for HIV in our study, 14 (93%) did not know their status before being tested in the study. The prevalence of HIV testing among MSM in Beijing is low; almost all HIV-positive men in our study were unaware of their infection. Our findings suggest an urgent need to promote HIV testing among MSM in Beijing.

Adolescent↗

Construction of the recombinant adenovirus vector carrying antisense multidrug resistance gene.

BACKGROUND: Multidrug resistance proteins serve as transporters for chemical drugs in human malignancies. The objective of this study was to construct a homologous recombinant adenovirus carrying a reversal fragment of multidrug resistance gene 1 (mdr1) gene cDNA sequence. METHODS: The fragment of the mdr1 gene from the plasmid pHaMDR1-1 carrying the whole human mdr1 cDNA sequence was inserted reversely into the shuttle plasmid pAdTrack-CMV of adenoviral vector system AdEasy. The homologous recombination process was taken place in E. coli BJ5183 with the backbone plasmid pAdEasy-1. After packaging in 293 cells, recombinant adenoviral plasmid was generated. The recombinant adenoviral plasmid was identified by polymerase chain reaction (PCR), restriction endonucleases digest, DNA sequence analysis and fluorescence microscopic photograph, respectively. RESULTS: The recombinant adenovirus pAdEasy-GFP-ASmdr1 was successfully constructed and identified by PCR, restriction digest, and sequencing with strong green fluorescence expression in fluorescence microscopic photograph. CONCLUSIONS: The recombinant adenoviral mdr1 vector would introduce the antisense mdr1 gene into the human multidrug resistance hepatocellular cell line effectively, which would provide an experimental basis to study the multidrug resistance in human hepatocellular carcinoma.

Adenoviridae↗

[Clinical study of shenqi fuzheng injection and chemotherapy in CHOP protocol in treating malignant lymphoma].

OBJECTIVE: To compare the efficacy and adverse reaction of chemotherapy in CHOP protocol (CT-CHOP) alone or compared with Shenqi Fuzheng injection (SFI) for treatment of moderate malignant non-Hodgkin's lymphoma. METHODS: Sixty patients were divided into 2 groups, the treated group (n = 32) treated with CT-CHOP plus SFI for 5.7 cycles on average and the control group (n = 28) treated with CT-CHOP alone for 5.6 cycles on average. RESULTS: In the treated group, 18 patients were completely remitted (CR), 4 were partially remitted (PR), 7 were unchanged (NC), 3 were progressively deteriorated (PD), with the total remission rate of 68.8%, while in the control group, 13 were CR, 4 PR, 7 NC and 4 PD, the total remission rate being 60.7%. After treatment, the levels of CD3, CD4 and CD4/CD8 increased and CD8 decreased significantly in the treated group (P <0.05). Patients' quality of life (QOL) in the treated group was improved more obviously than that in the control group (P < 0.01), and the incidence rate of adverse reaction as leucopenia, neurotoxicity, and cardiac toxicity were lower in the treated group than those in the control group (P<0.01). CONCLUSION: Shenqi Fuzheng injection combined with CT-CHOP on malignant non-Hodgkin's lymphoma can reduce the adverse reaction of chemotherapy, ameliorate the compliance of patients to chemotherapy, and improve the immune function and QOL of patients.

Adult↗

[Recombinant adenovirus vectors carrying antisense matrix metalloproteinase-2 inhibits hepatocellular carcinoma growth in vivo].

OBJECTIVE: To investigate the inhibitory effect of a recombinant adenoviral vector carrying antisense matrix metalloproteinase-2(MMP2) on the growth of hepatocellular carcinoma(HCC) in vivo. METHODS: The recombinant adenoviral vector carrying antisense MMP2(Ad-MMP2(AS))which had been constructed by us in readiness was used to infect the human HCC cell line (Bel-7402). Then the invasiveness of the Bel-7402 cells was assayed in Matrigel, and the production of MMP2 in the Bel-7402 cells was detected with Western blot analysis and Gelatin zymography. After the Ad-MMP2(AS)-infected Bel-7402 cells being subcutaneously inoculated in nude mice, the production of tumors was under observation, and then Ad-MMP2(AS) was injected intratumorally into the pre-existing tumors. RESULTS: Compared with PBS or Ad-CMV-infected cells, infection of Bel-7402 cells with Ad-MMP2(AS) significantly reduced MMP2 enzyme activity, the invasiveness resulted in 52% reduction in Matrigel assays, and the tumor volume displayed a 4.3-fold reduction in nude mice. In addition, direct intratumoral injection of Ad-MMP2(AS) into pre-existing tumors significantly impaired the further expansion of the tumor mass and resulted in a 63% reduction in tumor cell growth. CONCLUSION: The recombinant adenovirus with antisense MMP2 can effectively inhibit the invasiveness and growth of Bel-7402 cells in vitro and in vivo, and has a therapeutic potential for HCC.

Adenoviridae↗

[Cytological and embryological observation on the cross of autotriploid x diploid in rice].

In this report, the process of hybridization between different ploidy levels was observed in rice. Autotriploid (2n = 36) 149-B, generated naturally from the twin-seedling rice population SAR-2, was used as the female parent crossing with a normal diploid variety Shuhui 363. The processes of fertilization and embryological development were investigated. The pollen could germinate in triploid tissue of pistil normally and arrive at micropyle. But the percentage of double fertilization was only 8.89%, and the percentage of seed setting was 0.566%. The hybridization obstacles mainly occurred in the process of fertilization. Barriers of double fertilization, prolongation and abnormal development of proembryo, and even development stopping or differentiation failure of embryo and/or endosperm could result in abnormal development and abortion of zygote.

Diploidy↗

Effects of multidrug resistance, antisense RNA on the chemosensitivity of hepatocellular carcinoma cells.

BACKGROUND: Multidrug resistance is a major obstacle in cancer chemotherapy. We examined whether the antisense RNA of multidrug resistance gene 1 (mdr1) could reverse multidrug resistance in the human hepatocellular carcinoma (HCC) cell line SMMC7721/ADM. METHODS: The recombinant adenoviruses pAdEasy-GFP-ASmdr1 product was produced by the adenoviral vector AdEasy system, which can express antisense RNA against the mdr1 gene. Following that, the recombinant adenovirus was transfected into the P-glycoprotein-producing multidrug resistance cell line, SMMC7721/ADM human HCC cells resistant to adriamycin (ADM) and daunorubicin (DNR). In order to investigate the reversal of multidrug resistance phenotype, we measured the expression of mdr1 mRNA by RT-PCR and the production of P-glycoprotein by flow cytometry. The sensitivities for ADM and DNR SMMC7721/ADM cells were examined by [3-(4, 5-dimethylthi-azol-2-yl)-2,5 diphenyl-terazolium bromide] (MTT) analysis. RESULTS: The low-level expression of mdr1 mRNA and P-glycoprotein production were observed in parental sensitive cells SMMC/7721 in addition to the overexpression of mdr1 mRNA and P-glycoprotein in SMMC7721/ADM cells. The transfection of antisense-RNA into SMMC7721/ADM cells resulted in decreases of mdr1 mRNA and P-glycoprotein, but increase of drug sensitivities. The sensitivities of transfected SMMC7721/ADM cells to ADM and DNR in IC50 reduced by 31.25% and 62.96% respectively. CONCLUSIONS: Mdr1 antisense RNA can increase the sensitivities of SMMC7721/ADM cells to anticancer drug by decreasing the expression of the mdr1 gene and inhibiting P-glycoprotein expression. This strategy may be applicable to cancer patients with P-glycoprotein mediated multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Dynamic formation of coordination polymers versus tetragonal prisms and unexpected magnetic superexchange coupling mediated by encapsulated anions in the cobalt(II) 1,3-bis(pyrid-4-ylthio)propan-2-one series.

The reactions of cobalt(II) halides and flexible ligand L [L=1,3-bis(pyrid-4-ylthio)propan-2-one] under different conditions generated a series of complexes with various structural motifs ranging from tetragonal-prismatic cages to 1-3D coordination polymers. The layer diffusion of cobalt(II) chloride and L in methanol/acetone at 25 degrees C gave rise to a 3D polymer, [Co(L)2Cl2].Me2CO. At 30 degrees C, the slow diffusion of diethyl ether into the blue dimethylformamide (DMF) solution of complex 1 afforded a 1D polymer, Co(L)Cl2(DMF)2. However, at 10 degrees C, the diffusion of diethyl ether into the DMF solution of complex 1 produced a tetragonal-prismatic cage, [Co2(L)4Cl2]Cl2.Et2O.DMF.2MeOH.4H2O. The reaction of cobalt(II) bromide and L in DMF at 10 degrees C yielded a dimer, [Co2(L)4Br2]Br2.6DMF.2H2O, with a cage structure similar to. The preparation of the series of compounds indicates the subtle relationship between structures and tunable reaction conditions. It is also found that the structural motifs vary according to the ligand conformations and that the formation of tetragonal-prismatic cages and may be templated by anionic guests. Magnetic studies on complexes in a temperature range 4-300 K disclose that L is unfavorable for a long-range magnetic interaction; however, intramolecular spin-coupling constants of -19.6 and -21.5 cm-1 for and indicate rather strong magnetic superexchanges arising from the overlap of the dz2 orbitals of the cobalt(II) and pz orbitals of the encapsulated halide anions. Electron paramagnetic resonance (EPR) spectra of complexes 3 and 4 in solution and solid give information that both complexes are high-spin cobalt(II) compounds with a rhombic distortion of the axial zero-field splitting. Interestingly, the intramolecular magnetic-exchange coupling in 3 and 4 mediated by the encapsulated anion Cl- or Br- is also reflected by the EPR spectra.

Journal Article↗