Search Results (165)

Marine invertebrates produce a remarkable diversity of polyhydroxylated steroids and secosteroids whose structural features—particularly vicinal (1,2-)diols, 1,3-diols, and clustered hydroxyl arrays—make them well suited for coordination with boron species. In the marine environment, where boron is abundant, chemically stable, and predominantly present as borate under mildly alkaline conditions, such interactions are not only plausible but may be widespread. This review examines the chemistry of boron–steroid complexation in marine systems, emphasizing how rigid steroidal frameworks preorganize diol motifs to form reversible yet stable borate esters under environmentally relevant conditions. We discuss how polyhydroxy steroids may exist in dynamic equilibria between free and boron-bound forms, with speciation governed by pH, boron concentration, and local microenvironmental factors rather than enzymatic control. Boron complexation can modulate key physicochemical properties, including solubility, conformation, and membrane affinity, thereby influencing the biological activity of marine steroids without covalent modification of the carbon framework. By integrating examples from sponges, echinoderms, and corals together with well-characterized model polyols, this review highlights boron complexation as an underrecognized but potentially important factor influencing the structure, function, and bioactivity of marine steroid metabolites. Full article

This study explores a novel class of polynuclear superhalogen anions featuring heterovalent central atoms from groups 13 (B, Al) and 15 (P, As). The investigated species follow a modified general formula, (X_nY_n’F_{{(3n+5n’)+1}})⁻ where X = B and/or Al, Y = P and/or As, and n + n′ = 2–4. Low-energy isomers were identified using the Coalescence Kick method and subsequently optimized at the MP2/aug-cc-pVDZ level of theory. Electronic stability was assessed via the outer valence Green’s function (OVGF) approach with the same aug-cc-pVDZ basis set. All examined anions exhibit exceptional electronic stability, with vertical electron detachment energies (VDEs) ranging from 10.70 to 12.37 eV, significantly exceeding the superhalogen threshold of 3.65 eV. Thermodynamic analyses indicate that aluminum atoms play a crucial role in stabilizing larger clusters by acting as a structural “glue”, thereby suppressing fragmentation through the loss of neutral XF₃ or YF₅ units. In contrast, larger non-metallic analogs show an increased propensity toward dissociation. The potential of the heterovalent polynuclear superhalogen anions as weakly coordinating anions (WCAs) was further evaluated through molecular electrostatic potential (ESP) analysis. The results demonstrate that combining different central atoms within boron-based frameworks leads to a more homogeneous charge distribution, enhancing weakly coordinating behavior. Full article

Poly(amidoamine) (PAMAM) and poly-L-lysine (PLL) dendrimers have emerged as highly versatile macromolecular platforms with significant potential in biomedical applications, owing to their well-defined architecture, tunable surface chemistry, and capacity for multivalent functionalization. Their ability to carry substantial molecular payloads and to be engineered for selective interactions with biological systems has positioned them as attractive candidates for targeted drug delivery, including the transport of boron-rich compounds. Recent advances in dendrimer chemistry have enabled the incorporation of boron clusters into PAMAM and PLL structures, creating hybrid systems designed to enhance cellular uptake, improve tumor selectivity, and increase boron accumulation within malignant tissues. Given the growing interest in boron neutron capture therapy (BNCT), the integration of boron clusters into dendrimer structures represents a particularly promising direction for enhancing boron delivery to tumors. This manuscript reviews current knowledge on PAMAM and PLL dendrimers and their boron-functionalized derivatives, summarizing findings from cell culture studies, in vivo models, and clinical or preclinical investigations. Particular attention is given to both the advantageous properties of these dendrimers—such as improved delivery efficiency and biocompatibility—and their potential undesirable biological effects. As such, PAMAM and PLL dendrimers represent an important and evolving class of carriers that may significantly advance the effectiveness of boron neutron capture therapy (BNCT) in cancer treatment. Full article

The North China Plain is one of the largest plains in China, where domestic water supply, agricultural irrigation, and industrial production rely on groundwater resources. Groundwater quality is increasingly affected by the combined effects of intense human activity and geological conditions. To ensure sustainable groundwater utilization, it is crucial to investigate the hydrogeochemical processes linked to hydrogeological conditions. In this study, 85 samples were collected from cold wells and 56 samples from geothermal wells in North China. By integrating self-organizing mapping (SOM), hydrochemical and isotopic analysis, nitrate distribution, water quality index (WQI), and human health risk assessment (HHRA) methodologies, we systematically evaluated the spatial variability of groundwater quality and the associated health risks in the region. Hydrochemical analysis indicates that groundwater recharge is primarily driven by atmospheric precipitation. Shallow cold groundwater in Cluster 1 exhibited a mixed phase, whereas geothermal water in Clusters 2 and 3 and cold groundwater in Cluster 4 predominantly displayed a Na-Cl type. Cation exchange processes are the primary factors controlling ion composition. Water quality assessment studies indicate that 75.15% of the groundwater is suitable for drinking. The average water quality index of the geothermal water was higher than that of the cold water. Shallow groundwater in plains is significantly affected by agricultural activities, typically manifested as elevated NO₃⁻ concentrations. Arsenic and boron are the primary non-carcinogenic risk pollutants in geothermal water, and children are more vulnerable than adults. The non-carcinogenic risk zones for cold wells were primarily distributed in Shijiazhuang, Baoding, and the coastal areas downstream of the Yellow River. Tianjin has high-risk geothermal water. Therefore, effective strategies must be implemented to protect this valuable water resource and achieve sustainable development in the region. Full article

Background: Radiosensitizers can be used to enhance tumor response and mitigate toxicity in healthy tissues during radiation therapy. This study investigates the radiosensitizing potential of the metallacarborane Fe/⁵⁷Fe-ferrabisdicarbollide in SK-BR-3 and MDA-MB-231 breast cancer cells, using two distinct gamma-photon sources: high-dose ⁶⁰Co (2.08 Gy) and low-dose ⁵⁷Co (37.55 mGy, ⁵⁷Fe Mössbauer effect). Methods: We evaluated cell viability and survival in 2D monolayer and 3D spheroid cultures, as well as the mechanism of cell death (ROS production, apoptosis or necrosis). Computational dosimetry was used to calculate the average absorbed dose. Results: In 2D models, both radiation sources induced reduced viability and increased ROS, with distinct cell death patterns dependent on the source (apoptosis or necrosis). Comparing 2D and 3D MDA-MB-231 models revealed that spheroid survival was significantly more impaired. The low-dose ⁵⁷Co source caused a significant radiosensitization in MDA-MB-231 spheroids, dramatically impacting viability and survival. This effect is attributed to the Mössbauer effect, where the resonant absorption of 14.41 keV radiation by ⁵⁷Fe leads to a massive, localized dose enhancement. The subsequent cascade of Auger and conversion electrons (local high LET) caused significantly greater cellular damage than sparse photon radiation. Conclusions: Fe/⁵⁷Fe-ferrabisdicarbollide demonstrates a potent radiosensitizing effect depending on the cell model and the radiation source used. Crucially, the observed radiosensitization allows for the development of a new, more efficient cancer radiotherapy approach that can achieve therapeutic efficacy using a significantly lower radiation dose to the patient. This paves the way for safer and better-tolerated cancer treatments. Full article

Background: Boron neutron capture therapy (BNCT) represents a highly selective therapeutic modality for recalcitrant cancers, leveraging the nuclear reaction initiated by thermal neutron capture in boron-10 (¹⁰B) to deliver high-linear energy transfer radiation (α-particles and ⁷Li ions) directly within tumor cell boundaries. However, the widespread clinical adoption of BNCT is critically hampered by the pharmacological challenge of achieving sufficiently high, tumor-selective intracellular ¹⁰B concentrations (20–50 μg of ¹⁰B/g tissue). Conventional small-molecule boron carriers often exhibit dose-limiting non-specificity, rapid systemic clearance, and poor cellular uptake kinetics. Methods: To overcome these delivery barriers, we synthesized and characterized a novel dual-modality nanoplatform based on highly biocompatible, functionalized graphene oxide (GO). This platform was structurally optimized via covalent conjugation with high-boron content carborane clusters (dodecacarborane derivatives) for enhanced BNCT efficacy. Crucially, the nanocarrier was further decorated with plasmonic gold nanostructures (AuNPs), endowing the system with intrinsic surface-enhanced Raman scattering (SERS) properties, enabling real-time, high-resolution intracellular tracking and quantification. Results: We evaluated the synthesized GO@Carborane@Au nanoplatforms for their stability, cytotoxicity, and internalization characteristics. Cytotoxicity assays demonstrated excellent biocompatibility against the non-malignant human keratinocyte line (HaCaT) while showing selective toxicity (upon irradiation, if tested) and high cellular uptake efficiency in the aggressive human glioblastoma tumor cell line (T98G). The integrated plasmonic component allowed for the successful, non-destructive monitoring of nanoplatform delivery and accumulation within both HaCaT and T98G cells using SERS microscopy, confirming the potential for pharmacokinetic and biodistribution studies in vivo. Conclusions: This work details the successful synthesis and preliminary in vitro validation of a unique graphene oxide-based dual-modality nanoplatform designed to address the critical delivery and monitoring challenges of BNCT. By combining highly efficient carborane delivery with an integrated photonic trace marker, this system establishes a robust paradigm for next-generation theranostic agents, significantly advancing the potential for precision, image-guided BNCT for difficult-to-treat cancers like glioblastoma. Full article

Silica-based sorbents covalently modified with polyhedral boron clusters represent a promising platform for highly selective separation materials, yet robust and synthetically accessible immobilization protocols remain underdeveloped. In this work, novel sorbents based on commercially available silica gels functionalized with closo-dodecaborate anions were synthesized and systematically characterized. Two immobilization strategies were compared: direct nucleophilic addition of surface aminopropyl groups to the nitrilium derivative (Bu₄N)[B₁₂H₁₁NCCH₃] and sol–gel condensation of a pre-formed boron-containing APTES-derived silane. Covalent attachment via amidine bond formation was confirmed by solution and MAS ¹¹B NMR spectroscopy, IR spectroscopy, elemental analysis/ICP-OES, and SEM. The direct grafting route afforded a boron loading of 4.5 wt% (≈20% of the theoretical capacity), with the efficiency limited by electrostatic repulsion between anionic amidine fragments on the negatively charged silica surface, whereas the APTES route gave lower absolute loading (0.085 mmol/g) due to the low specific surface area of the coarse silica support. Despite the moderate degree of functionalization, the resulting boron cluster–modified silica gels are attractive candidates for specialized chromatographic applications, where the unique hydrophobic and dihydrogen-bonding properties of closo-dodecaborates may enable selective retention of challenging analytes and motivate further optimization of surface morphology and immobilization conditions. Full article

This work explores a novel and efficient synthetic approach to a new class of boron cluster derivatives via the nucleophilic addition of stabilized phosphorus ylides, Ph₃P=CHR² (R² = COOEt, CN), to a series of nitrilium salts of the closo-decaborate anion, [2-B₁₀H₉NCR¹]⁻ (R¹ = Me, Et, ⁿPr, ⁱPr, Ph). The reaction proceeds regio- and stereospecifically, affording a diverse range of iminoacyl phosphorane derivatives, [2-B₁₀H₉NH=C(R¹)C(PPh₃)R²]⁻, in high isolated yields (up to 95%). The obtained compounds (10 examples) were isolated as tetrabutylammonium or tetraphenylphosphonium salts and thoroughly characterized by multinuclear NMR (¹¹B, ¹H, ¹³C, ³¹P), high-resolution mass spectrometry, and single-crystal X-ray diffraction. The reaction feasibility was found to be strongly influenced by the steric hindrance of the R¹ group. Furthermore, the practical utility of these novel hybrids was demonstrated by employing the [2-B₁₀H₉NH=C(CH₃)C(COOC₂H₅)=PPh₃]⁻ anion as a highly effective membrane-active component in ion-selective electrodes. The developed tetraphenylphosphonium (TPP⁺) sensor exhibited a near-Nernstian response, a low detection limit of 3 × 10⁻⁸ M, and excellent selectivity over a range of common inorganic and organic cations, showcasing the potential of closo-borate-based ionophores in analytical chemistry. Full article

Boron is a trace element with multifaceted chemical and biological properties that underpin its emerging relevance in human health and medicinal chemistry. Although present in organisms at very low concentrations, boron participates in key physiological processes, including mineral metabolism, bone homeostasis, hormonal regulation, immune modulation, and redox balance. Its unique electronic structure—characterized by electron deficiency and the ability to form multi-center bonds—gives rise to diverse allotropic, cluster, and coordination chemistries, enabling the formation of biologically active complexes and therapeutic agents. Dietary boron, derived mainly from plant-based foods, is efficiently absorbed and predominantly excreted by the kidneys, showing a strong correlation between intake and urinary levels. Current evidence suggests beneficial effects of boron on bone mineral density, cognitive function, inflammation, antioxidant defenses, and metabolic regulation, although the precise molecular mechanisms remain partially understood. In medicinal chemistry, a broad spectrum of boron-containing compounds—including borates, boronic acids, boronated amino acids, carboranes, and metallacarboranes—has gained clinical and preclinical importance. These compounds serve as enzyme inhibitors, antimicrobial and anti-inflammatory agents, metabolic modulators, and critical boron carriers in boron neutron capture therapy (BNCT), which leverages the neutron-capture properties of ¹⁰B for targeted cancer treatment. Advances in synthesis, functionalization, and nanocarrier design have expanded the therapeutic potential of boron-based molecules. Ongoing research aims to optimize their selectivity, biodistribution, safety, and diagnostic integration. Overall, boron represents a versatile and rapidly developing component of modern biomedical science, with promising implications for oncology, infectious diseases, metabolic disorders, and precision medicine. Full article

Background/Objectives: To enhance the anti-glioma activity of erlotinib, we previously developed a series of carborane-based analogs exploiting the concept of three-dimensional bioisosterism. These carboranes generally exhibited improved cytotoxicity against glioma cell lines compared with the parent compound erlotinib and additionally showed varying degrees of EGFR inhibition. Given the well-described influence of lipophilicity on pharmacological properties, we aimed to determine this parameter for the new analogs and explore its correlations with biological behaviors. Methods: Lipophilicity was assessed experimentally, through chromatographic procedure, in terms of R_M⁰ and theoretically via fragment-based logP calculations (flogP) using Hansch–Fujita hydrophobic parameters π of some substituents and the experimentally determined logD_{n-octanol/buffer(7.4)} of 4-chloro-6,7-bis(2-methoxyethoxy)quinazoline. Additionally, the electronic properties of the carborane clusters were considered using the NMR chemical shifts of cluster carbon-bound protons. Results: For the series of carboranes, the R_M⁰ discretely correlated to the flogP. Neither R_M⁰ nor flogP correlated with the electronic characteristics of the carboranes. From the correlation between R_M⁰ and flogP, it was possible to estimate the π value for a nido-carboranyl substituent. Cytotoxicities, against glioma cells, exhibited a parabolic dependence on lipophilicity, finding optimal flogP for each cellular system. Some tendencies were observed between EGFR inhibition and flogP, requiring more hydrophilic compounds for optimal wild-type EGFR inhibition or a specific flogP for mutant EGFR inhibition. It was observed that the electronic features of the boron cluster also influenced both biological activities studied. Conclusions: Unlike our previous reports, which focused on the synthesis and biological evaluation of carborane-erlotinib analogs, this study establishes for the first time the correlation of lipophilicity and electronic features with cytotoxic and EGFR-inhibitory activities, providing new insights into their structure–activity relationships. Full article

In this research article, a silicon carbide (SiC) nanocluster has been designed and characterized as an anode electrode for lithium (Li), sodium (Na), potassium (K), beryllium (Be), magnesium (Mg), boron (B), aluminum (Al) and gallium (Ga)-ion batteries through the formation of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. A vast study on energy-saving by SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC complexes was probed using computational approaches accompanying density state analysis of charge density differences (CDDs), total density of states (TDOS) and molecular electrostatic potential (ESP) for hybrid clusters of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC. The functionalization of Li, Na, K, Be, Mg, B, Al and Ga metal/metalloid elements can raise the negative charge distribution of carbon elements as electron acceptors in SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. Higher Si/C content can increase battery capacity through SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters for energy storage processes and to improve the rate performance by enhancing electrical conductivity. Full article

The emergence of drug-resistant influenza virus strains necessitates the development of novel antiviral agents with unique mechanisms of action. This study presents the synthesis and in vitro evaluation of a new class of antiviral compounds: sodium salts of amino acid ester conjugates based on the closo-dodecaborate anion [B₁₂H₁₂]²⁻, linked via a tetrahydropyran-derived spacer (Na₂[B₁₂H₁₁O(CH₂)₆C(O)X], where X = L-Trp-OMe (Na₂2); L-His-OMe (Na₂3); L-Met-OMe (Na₂4); Pld-OMe (Na₂5)). The antiviral activity was assessed against contemporary, multidrug-resistant influenza A virus strains, including A/Cheboksary/125/2020 (H1N1)pdm09 and A/IIV-Orenburg/83/2012 (H1N1)pdm09. Cross-platform comparison revealed that the dodecaborate-tryptophan conjugate Na₂2 exhibited comparable efficacy to its lead decaborate analog against the Orenburg strain while demonstrating potent activity (IC₅₀ = 5.0 µg/mL) against the Cheboksary strain with reduced susceptibility to neuraminidase inhibitors (oseltamivir; zanamivir) and complete resistance to M2 channel blockers. The histidine-based conjugate Na₂3 also showed significant efficacy against the Cheboksary strain, while methionine and lactam derivatives (Na₂4; Na₂5) remained inactive. This work confirms boron clusters as versatile platforms for antiviral development and establishes structure–activity relationships crucial for optimizing both B₁₀ and B₁₂-based therapeutics against resistant influenza strains. Full article

The significant side effects associated with platinum-based anticancer agents have driven the continuous pursuit of novel, non-platinum-based metal compounds. Ruthenium-based organometallic compounds have emerged as promising alternatives, owing to their distinctive and adaptable biochemical properties. The research efforts are focused on the development of ruthenacarborane-based anticancer drugs. The combination of ruthenium(II) complexes, recognized for their inherent anticancer potential, with carboranes, boron-rich clusters possessing unique chemical and physical characteristics, and NSAIDs, known to inhibit COX, an enzyme overexpressed in tumors, offers a novel approach for cancer therapy. Consequently, combining these three moieties into a single molecule represents a compelling strategy to develop drugs with a dual mode of action. Herein, we report the synthesis of a series of ruthenacarborane-(η⁶-p-cymene)–NSAID conjugates (4a, 4b, 5b, and 6b) by linking NSAIDs (flurbiprofen, fenoprofen, and ibuprofen) to ruthenacarborane complexes using methylene and ethylene spacers, while maintaining the integrity of the sensitive ester groups present in the system. The synthesized conjugates were thoroughly characterized using multinuclear (¹H, ¹¹B, and ¹³C) NMR spectroscopy. Notably, the conjugates demonstrated low COX inhibition and no cytotoxic potential against different cancer cell lines, probably due to oxidative deactivation confirmed by cyclic voltammetry (CV). This indicates that the conjugation of this type of ruthenacarborane with NSAIDs does not result in novel anticancer drugs. Full article

The development of highly selective and sensitive gas sensors is essential for detecting toxic pollutants, such as carbon monoxide (CO), which pose severe health and environmental risks. In this work, the adsorption of CO molecules on Ni_6−xCu_x (x = 0–6) clusters supported on hexagonal boron nitride quantum dots with nitrogen vacancies (h-BN_VQDs) is explored through density functional theory (DFT) calculations. For this purpose, the stability of the metallic clusters supported on the boron nitride sheet was calculated, and the adsorption properties of the CO molecule on the Ni_6−xCu_x (x = 0–6)/h-BN_VQDs composite were determined. The results demonstrated a high binding energy between Ni_6−xCu_x (x = 0–6) clusters and the h-BN_VQDs sheets, suggesting that Ni-Cu clusters are highly stable on h-BN_VQDs sheets. For CO adsorption, adsorption energy and charge transfer calculations indicated that the Ni₆ and Ni_6−xCu_x (x = 2 and 3) clusters exhibit the strongest CO binding and highest charge transfer, suggesting them as good candidates for CO gas sensing. These findings provide theoretical insights into the rational design of bimetallic catalysts for gas-sensing applications. Full article

The aromaticity of small boron clusters remains under scrutiny due to persistent inconsistencies between magnetic and electronic descriptors. Here, we reexamine B₃⁻, B₃⁺, B₄, B₄²⁺, and B₄²⁻ using a multidimensional approach that integrates Adaptive Natural Density Partitioning, Electron Density of Delocalized Bonds, magnetically induced current density, and the z-component of the induced magnetic field. We introduce a model in which σ-aromaticity arises from two distinct delocalization topologies: a radial 2e⁻ σ-pathway and a tangential multicenter circuit formed by alternating filled and vacant sp² orbitals. This framework accounts for the evolution of aromaticity upon oxidation or reduction, preserving coherence between electronic structure and magnetic response. B₃⁻ features cooperative radial and tangential σ-delocalization, together with a delocalized 2e⁻ π-bond, yielding robust double aromaticity. B₃⁺ retains σ- and π-aromaticity, but only via a tangential 6e⁻ σ-framework, leading to a more compact delocalization and slightly attenuated ring currents. In B₄, the presence of a radial 2e⁻ σ-bond and a 4c–2e π-bond confers partial aromatic character, while the tangential 8e⁻ σ-framework satisfies the 4n rule and induces a paratropic current. In contrast, B₄²⁺ lacks the radial σ-component but retains a tangential 8e⁻ σ-circuit and a 2e⁻ 4c–2e π-bond, leading to a σ-antiaromatic and π-aromatic configuration. Finally, B₄²⁻, exhibits delocalized π- and σ-circuits, yielding consistent diatropic ring currents, which confirms its fully doubly aromatic nature. Altogether, this analysis underscores the importance of resolving σ-framework topology and demonstrates that, when radial and tangential contributions are correctly distinguished, Hückel’s rule remains a powerful tool for interpreting aromaticity in small boron rings. Full article