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Angewandte Chemie (International Ed. in... May 2024Attempts to create a novel Mg-Be bond by reaction of [(DIPePBDI*)MgNa]2 with Be[N(SiMe3)2]2 failed; DIPePBDI* = HC[(tBu)C=N(DIPeP)]2, DIPeP = 2,6-Et2C-phenyl. Even at...
Attempts to create a novel Mg-Be bond by reaction of [(DIPePBDI*)MgNa]2 with Be[N(SiMe3)2]2 failed; DIPePBDI* = HC[(tBu)C=N(DIPeP)]2, DIPeP = 2,6-Et2C-phenyl. Even at elevated temperatures, no conversion was observed. This is likely caused by strong steric shielding of the Be center. A similar reaction with the more open Cp*BeCl gave in quantitative yield (DIPePBDI)MgBeCp* (1). The crystal structure shows a Mg-Be bond of 2.469(4) Å. Homolytic cleavage of the Mg-Be bond requires ΔH = 69.6 kcal mol-1 (cf. CpBe-BeCp 69.0 kcal mol-1 and (DIPPBDI)Mg-Mg(DIPPBDI) 55.8 kcal mol-1). Natural-Population-Analysis (NPA) shows fragment charges: (DIPePBDI*)Mg +0.27 / BeCp* -0.27. The very low NPA charge on Be (+0.62) compared to Mg (+1.21) and the strongly upfield 9Be NMR signal at -23.7 ppm are in line with considerable electron density on Be and the formal oxidation state assignment of MgII-Be0. Despite this Mgδ+-Beδ- polarity, 1 is extremely thermally stable and unreactive towards H2, CO, N2, cyclohexene and carbodiimide. It reacted with benzophenone, azobenzene, phenyl acetylene, CO2 and CS2. Reaction with 1-adamantyl azide led to reductive coupling and formation of an N6-chain. The azide reagent also inserted in the Cp*-Be bond. The inertness of 1 is likely due to bulky ligands protecting the Mg-Be unit.
PubMed: 38818668
DOI: 10.1002/anie.202408422 -
Physical Chemistry Chemical Physics :... May 2024An analysis of the thermodynamic and kinetic stability and the nature of the chemical bond in hypercoordinated compounds with the formula BeHNg (Ng = He-Rn) through...
An analysis of the thermodynamic and kinetic stability and the nature of the chemical bond in hypercoordinated compounds with the formula BeHNg (Ng = He-Rn) through high-level calculations is presented in this work. Thermochemical calculations show that, for the heavier noble gases (Ar-Rn), these systems are thermodynamically stable at room temperature; however, this stability decreases due to a weakening of the Be-H interaction, while the Be-Ng bond strengthens going down the periodic table. These results are complemented by Born Oppenheimer molecular dynamics simulations, in which the increasing tendency to dissociate the Be-H bond is evidenced. The nature of the chemical bonding depends on the analysis performed. On the one hand, the interacting quantum atoms method indicates that the covalent contribution is around 25 to 30%. On the other hand, the electron density topology indicates a covalent nature for compounds with Kr-Rn, while Hirshfeld population analysis in conjunction with Mayer's bond order establishes polar covalent behavior. The geometrical parameters and natural energy decomposition analysis (NEDA) indicate a covalent nature, allowing us to consider that the Be-Ng bond has a partially covalent character.
PubMed: 38809129
DOI: 10.1039/d4cp00468j -
Life (Basel, Switzerland) May 2024Objectives-Metallic elements and fibrin clot properties have been linked to stroke. We examined metallic and nonmetallic elements, fibrin clot lysis time (CLT), and...
Objectives-Metallic elements and fibrin clot properties have been linked to stroke. We examined metallic and nonmetallic elements, fibrin clot lysis time (CLT), and maximum absorbance (Abs) in relation to ischemic stroke. Design-A case-control study of ischemic stroke patients vs. healthy individuals. Subjects and Methods-Plasma and serum were collected from 260 ischemic stroke patients (45.0% women; age, 68 ± 12 years) and 291 healthy controls (59.7% women; age, 50 ± 17 years). Fibrin CLT and Abs were measured using a validated turbidimetric assay. Serum elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). Data were analyzed by bivariate correlations and multiple or logistic regression. Results-In female stroke patients, copper, lithium, and aluminum were significantly lower compared with controls; in male stroke patients, potassium was lower, and beryllium was elevated. In female and male stroke patients, iron, zinc, nickel, calcium, magnesium, sodium, and silicon were significantly lower, while strontium was elevated. Positive correlations between fibrin clot properties and metals, observed in healthy controls, were lost in ischemic stroke patients. In multivariate regression analysis, fibrin CLT and/or Abs was associated with zinc, calcium, potassium, beryllium, and silicon in stroke patients and with sodium, potassium, beryllium, and aluminum in controls. In logistic regression analysis, stroke was independently associated with lithium, nickel, beryllium, strontium, boron, and silicon and with sodium, potassium, calcium, and aluminum but not with fibrin CLT/Abs. Conclusions-Various elements were associated with fibrin clot properties and the risk of ischemic stroke. Lithium, sodium, calcium, and aluminum abrogated the association of fibrin clot properties with ischemic stroke.
PubMed: 38792655
DOI: 10.3390/life14050634 -
Antibiotics (Basel, Switzerland) May 2024Valley surface water is considered a focal public health concern owing to the presence of multi-drug-resistant bacteria. The distribution of antimicrobial resistance...
Screening for Antibiotic Resistance Genes in Bacteria and the Presence of Heavy Metals in the Upstream and Downstream Areas of the Wadi Hanifah Valley in Riyadh, Saudi Arabia.
Valley surface water is considered a focal public health concern owing to the presence of multi-drug-resistant bacteria. The distribution of antimicrobial resistance (AMR) bacteria in the surface water is affected by the presence of multiple factors, including antibiotics coming from wastewater discharge or other contaminant sources such as pharmaceuticals, biocides, and heavy metals. Furthermore, there is evidence suggesting that high levels of antibiotic resistance genes (ARGs) can be transferred within bacterial communities under the influence of heavy metal stress. Hence, the primary aim of this study is to investigate the presence of heavy metals and bacterial ARGs in upstream as well as downstream locations of Wadi Hanifah Valley in Riyadh, Saudi Arabia. Sample collection was conducted at eighteen surface water sites within the valley in total. The selection of ARGs was associated with the most common antibiotics, including β-lactam, tetracycline, erythromycin, gentamicin, sulphonamide, chloramphenicol, vancomycin, trimethoprim, and colistin antibiotics, which were detected qualitatively using polymerase chain reaction (PCR) technology. The tested antibiotic resistance genes (ARGs) included ( (for the antibiotic class Beta-lactamases), (methicillin-resistant ), and (for the antibiotic class Tetracycline), (for the antibiotic class Beta-lactamases), (for the antibiotic class vancomycin), (for the antibiotic class colistin), (for the antibiotic class erythromycin), (for the antibiotic class Gentamicin), (for the antibiotic class sulphonamide), (for the antibiotic class Chlorophincol), and (for the antibiotic class trimethoprim). Moreover, an assessment of the levels of heavy metals such as lithium (Li), beryllium (Be), chromium (Cr), cobalt (Co), arsenic (As), cadmium (Cd), tin (Sn), mercury (Hg), and lead (Pb) was conducted by using inductively coupled plasma mass spectrometry (ICPMS). According to our findings, the concentrations of sulphonamide, erythromycin, and chloramphenicol ARGs (, , and ) were observed to be the most elevated. Conversely, two ARGs, namely and , were not detected in the samples. Moreover, our data illustrated a significant rise in ARGs in the bacteria of water samples from the upstream sites as compared with the water samples from the downstream sites of Wadi Hanifah Valley. The mean concentration of Li, Be, Cr, Co, As, Cd, Sn, Hg, and Pb in the water samples was estimated to be 37.25 µg/L, 0.02 µg/L, 0.56 µg/L,0.32 µg/L, 0.93 µg/L, 0.01 µg/L, 200.4 µg/L, 0.027 µg/L, and 0.26 µg/L, respectively, for the selected 18 sites. Furthermore, it was revealed that the concentrations of the screened heavy metals in the water samples collected from various sites did not surpass the maximum limits set by the World Health Organization (WHO). In conclusion, this study offers a concise overview of the presence of heavy metals and ARGs in water samples obtained from the Wadi Hanifah Valley in Riyadh, KSA. Such findings will contribute to the ongoing monitoring and future risk assessment of ARGs spread in surface water.
PubMed: 38786154
DOI: 10.3390/antibiotics13050426 -
Inorganic Chemistry May 2024The arrangement of functional groups exerts a crucial role in determining the characteristics of compounds. In this study, we synthesized two novel short-wave...
The arrangement of functional groups exerts a crucial role in determining the characteristics of compounds. In this study, we synthesized two novel short-wave ultraviolet (UV) nonlinear optical (NLO) crystals: KBe(SeO)(OH)·HO and KBe(SeO). Interestingly, the two compounds show the same SeO triangular pyramids and K-O polyhedra. However, the two compounds exhibit distinct beryllium-oxygen anion groups: BeO(OH) for KBe(SeO)(OH)·HO and BeO for KBe(SeO). This results in the SeO groups within the structure having different orientations, ultimately leading to the two compounds exhibiting completely different optical properties. KBe(SeO)(OH)·HO displays a large second harmonic generation (SHG) effect equivalent to 2× KHPO (KDP), coupled with a large birefringence of 0.078 at 546 nm. In contrast, the SHG effect and birefringence of KBe(SeO) are only 0.33× that of KDP and 0.024 at 546 nm, respectively. Structural analyses and theoretical calculations indicate that these pronounced differences in optical properties stem from variations in the arrangement of the SeO functional groups. This study not only sheds light on the correlation between crystal structure and optical behavior but also presents a hopeful avenue for the advancement of materials in the short-wave UV spectrum.
PubMed: 38781121
DOI: 10.1021/acs.inorgchem.4c01611 -
Journal of Applied Toxicology : JAT May 2024Beryllium sulfate (BeSO) can cause inflammation through the mechanism, which has not been elucidated. Mitochondrial DNA (mtDNA) is a key contributor of inflammation....
Beryllium sulfate (BeSO) can cause inflammation through the mechanism, which has not been elucidated. Mitochondrial DNA (mtDNA) is a key contributor of inflammation. With mitochondrial damage, released mtDNA can bind to specific receptors (e.g., cGAS) and then activate related pathway to promote inflammatory responses. To investigate the mechanism of mtDNA in BeSO-induced inflammatory response in 16HBE cells, we established the BeSO-induced 16HBE cell inflammation model and the ethidium bromide (EB)-induced ρ16HBE cell model to detect the mtDNA content, oxidative stress-related markers, mitochondrial membrane potential, the expression of the cGAS-STING pathway, and inflammation-related factors. Our results showed that BeSO caused oxidative stress, decline of mitochondrial membrane potential, and the release of mtDNA into the cytoplasm of 16HBE cells. In addition, BeSO induced inflammation in 16HBE cells by activating the cGAS-STING pathway. Furthermore, mtDNA deletion inhibited the expression of cGAS-STING pathway, IL-10, TNF-α, and IFN-β. This study revealed a novel mechanism of BeSO-induced inflammation in 16HBE cells, which contributes to the understanding of the molecular mechanism of beryllium and its compounds-induced toxicity.
PubMed: 38778435
DOI: 10.1002/jat.4631 -
The Journal of Chemical Physics May 2024In the past decade, natural orbital functional (NOF) approximations have emerged as prominent tools for characterizing electron correlation. Despite their effectiveness,...
In the past decade, natural orbital functional (NOF) approximations have emerged as prominent tools for characterizing electron correlation. Despite their effectiveness, these approaches, which rely on natural orbitals and their associated occupation numbers, often require hybridization with other methods to fully account for all correlation effects. Recently, a global NOF (GNOF) has been proposed [Piris, Phys. Rev. Lett. 127, 233001 (2021)] to comprehensively address both dynamic and static correlations. This study evaluates the performance of GNOF on strongly correlated model systems, including comparisons with highly accurate Full Configuration Interaction calculations for hydrogen atom clusters in one, two, and three dimensions. Additionally, the investigation extends to a BeH2 reaction, involving the insertion of a beryllium atom into a hydrogen molecule along a C2v pathway. According to the results obtained using GNOF, consistent behavior is observed across various correlation regions, encompassing a range of occupations and orbital schemes. Furthermore, distinctive features are identified when varying the dimensionality of the system.
PubMed: 38775739
DOI: 10.1063/5.0207325 -
Applied Radiation and Isotopes :... May 2024This study aimed to identify the optimal conditions for delivering sufficient doses to deep-seated lesions within short irradiation times for two boron carriers of...
This study aimed to identify the optimal conditions for delivering sufficient doses to deep-seated lesions within short irradiation times for two boron carriers of different T/N ratios. The therapeutic depth and irradiation time of a neutron beam for beam shaping assemblies (BSAs) with a Li or Be target and a MgF or CaF moderator were examined with the fast-neutron dose per epithermal neutron (FNR) as a parameter. When T/N = 3.61, the therapeutic depth was almost saturated at an FNR of about 10 × 10 Gy cm; when the FNR value was about 10 × 10 Gy cm, the therapeutic depth of the neutron beam for the BSA with a Be target and a MgF moderator was almost identical to that for the neutron beam for the BSA with a Be target and a CaF moderator, and slightly greater than those for the neutron beams for the BSAs with a Li target and a MgF or CaF moderator; moreover, the irradiation time of the neutron beam for the BSA with a Be target and a MgF moderator was shorter than that for the neutron beam for the BSA with a Be target and a CaF moderator. When T/N = 100, the therapeutic depths of the neutron beams for the BSAs varied greatly depending on the FNR, and were greater than the corresponding values for T/N = 3.61. We therefore concluded that the BSA with a Be target and a MgF moderator that produced a neutron beam with an FNR of about 10 × 10 Gy cm is optimal for delivering sufficient doses to deep-seated lesions in short irradiation times when T/N = 3.61, and stricter control over FNR is required when T/N = 100.
PubMed: 38772121
DOI: 10.1016/j.apradiso.2024.111359 -
Nature Chemistry May 2024Owing to its high toxicity, the chemistry of element number four, beryllium, is poorly understood. However, as the lightest elements provide the basis for fundamental...
Owing to its high toxicity, the chemistry of element number four, beryllium, is poorly understood. However, as the lightest elements provide the basis for fundamental models of chemical bonding, there is a need for greater insight into the properties of beryllium. In this context, the chemistry of the homo-elemental Be-Be bond is of fundamental interest. Here the ligand metathesis chemistry of diberyllocene (1; CpBeBeCp)-a stable complex with a Be-Be bond-has been investigated. These studies yield two complexes with Be-Be bonds: Cp*BeBeCp (2) and [K{(HCDippN)BO}]BeBeCp (3; Dipp = 2,6-diisopropylphenyl). Quantum chemical calculations indicate that the Be-Be bond in 3 is polarized to such an extent that the complex could be formulated as a mixed-oxidation state Be/Be complex. Correspondingly, it is demonstrated that 3 can transfer the 'beryllyl' anion, [BeCp], to an organic substrate, by analogy with the reactivity of sp-sp diboranes. Indeed, this work reveals striking similarities between the homo-elemental bonding linkages of beryllium and boron, despite the respective metallic and non-metallic natures of these elements.
PubMed: 38760434
DOI: 10.1038/s41557-024-01534-9 -
Chemistry, An Asian Journal May 2024Reaction of lithium 1,3-diamidopropane Li2(TripNCN) (TripNCN = [{(Trip)NCH2}2CH2]2-, Trip = 2,4,6-triisopropylphenyl) with BeBr2(OEt2)2 gave the diamido beryllium...
Reaction of lithium 1,3-diamidopropane Li2(TripNCN) (TripNCN = [{(Trip)NCH2}2CH2]2-, Trip = 2,4,6-triisopropylphenyl) with BeBr2(OEt2)2 gave the diamido beryllium complex, [(TripNCN)Be(OEt2)]. Deprotonation reactions between the bulkier 1,3-diaminopropane (TCHPNCN)H2 (TCHPNCN = [{(TCHP)NCH2}2CH2]2-, TCHP = 2,4,6-tricyclohexylphenyl) and magnesium alkyls afforded the adduct complexes [(TCHPNCN)Mg(OEt2)] and [(TCHPNCN)Mg(THF)2], depending on the reaction conditions employed. Treating [(TCHPNCN)Mg(THF)2] with the N-heterocyclic carbene:C{(MeNCMe)2} (TMC) gave [(TCHPNCN)Mg(TMC)2] via substitution of the THF ligands. Reactions of (ArNCN)H2 (Ar = Trip or TCHP) with Mg{CH2(SiMe3)}2, in the absence of Lewis bases, yielded the N-bridged dimers [{(ArNCN)Mg}2]. Salt metathesis reactions between alkali metal salts M2(TCHPNCN) (M = Li or K) and CaI2 or SrI2 led to the THF adduct compounds [(TCHPNCN)Ca(THF)3] and [(TCHPNCN)Sr(THF)4], the differing number of THF ligands in which are a result of the different sizes of the metals involved. The described complexes hold potential as precursors to kinetically protected, low oxidation state group 2 metal species.
PubMed: 38760323
DOI: 10.1002/asia.202400498