Selenious Acid Research Articles

Scalable, Highly Uniform, and Robust Colloidal Mie Resonators for All‐Dielectric Soft Meta‐Optics

AbstractAll‐dielectric nanoparticles (NPs) with high (>3.0) or moderate (1.7–3.0) refractive indices have become fundamental to meta‐optics, as they enable low‐loss, low‐heating, and quenching‐free magnetodielectric Mie resonances, which are difficult to achieve by use of plasmonic counterparts. However, a scalable and versatile synthetic route for such magnetodielectric NPs retaining high uniformity, roundness, and robustness has remained elusive. Thus, soft self‐assembly still represents an underutilized method in the optical engineer's toolset, which in turn limits the accessible range of meta‐optics. Herein, a gram‐scale and versatile synthesis of dielectric colloidal Mie resonators is presented, in which selenous acid precursors are converted into highly uniform, crystalline colloids by a low demand reaction. These crystalline selenium (c‐Se) colloids enable strong electric and magnetic resonances due to their moderate refractive index (2.8–3.2 at optical frequencies), while simultaneously satisfying the requirements of high uniformity, roundness, and robustness. Even with these exotic properties, c‐Se colloids are successfully self‐assembled into various all‐dielectric meta‐optics systems including (i) metafluids exhibiting directional scattering, (ii) metamolecules with nanogap‐dielectric resonances, and (iii) metacrystals with magnetodielectric bandgaps. The design space of all‐dielectric meta‐optics will be greatly expanded by utilizing soft self‐assembly of c‐Se colloids.

In My Element: Selenium

<i>In My Element</i>: Selenium

In-vitro cytotoxicity of java tea mediated selenium nanoballs against L6 cell lines

The emergence of Nanotechnology has provided a catholic research in recent years by intersecting with assorted branches of science and forming collision on all forms of life. At present there has been a prodigious excitement in the field of Nano pharmacology to seek the role of Nano selenium in individual healthcare and explains how selenium is a double edged sword in the pathologies of chronic diseases like Diabetes mellitus because of their inferior toxicity and ability to gradually release the bioactive principle and free selenium after ingestion. Thus the present study is an embryonic attempt and was aimed at the adroitful synthesis of selenium nanoballs from the aqueous extract of well known herbal tea leaves namely Java tea (Orthosiphon stamineus) using selenious acid solution. The synthesized Selenium nanoparticles were then subjected to various characterization techniques such as UV, FTIR, FESEM, EDAX and Zeta potential respectively. Finally the green synthesized SeNps were tested for their cytotoxic effect against L6 rat skeletal muscle cell lines. The pre clinical studies are underway to prove the insulin mimic activity of the selenium nanoparticles.&#x0D; Keywords: Selenium Nanoparticles, Java tea, L6 cell lines.

Green Synthesis of Selenium Nanoparticle Using Leaves Extract of Withania somnifera and Its Biological Applications and Photocatalytic Activities

The green Se NPs (selenium nanoparticles) are formed by simple mixing of Withania somnifera (W. somnifera) leaves extract and selenious acid (H2SeO3) solution. This mixture was stirred which gave a dispersion of Se NPs conjugated with W. somnifera secondary metabolites. The work was focused to determine the phytochemical analysis of leaves extract, green synthesis, its characterization and its applications. Screening analysis showed enormous phytoconstituents in leaves aqueous extract and simultaneously, the synthesized Se NPs by FT-IR spectrum confirm the presence of functional groups which were associated with bioactive molecules. The total flavonoid, phenolic and tannin contents in the aqueous extract were found to be 12.74, 40.54, and 156.33 μg/mg respectively. The suspension solution confirms the formation of Se NPs showed (310 nm) by UV analysis. X-ray diffraction study exhibits the amorphous nature of Se NPs. Se NPs were spherical in shape within the diameter range of 45–90 nm by FE-SEM. The intense, narrow width of selenium has high purity and was identified using EDX. The TEM analysis exhibited the amorphous nature of particles. Green synthesized Se NPs were found to possess significant antioxidant activity (IC50 – 14.81 μg/mg) and considerable antibacterial activity on Bacillus subtilis (12 mm), Klebsiella pneumoniae (14 mm) and Staphylococcus aureus (19.66 mm). Antiproliferative effects of Se NPs possess great growth control against A549 cells (IC50 at 25 μg/ml). Se NPs exhibit efficient methylene blue (MB) dye degradation in the presence of sunlight. The present results support the advantages of green method for the production of Se NPs having potential activities.Graphical Highlights• Withania somnifera leaves extract possesses active phytoconstituents and acts as reducing agents for the preparation of Se NPs and the capping by the phytoconstituents providing stability to Se NPs as evident from FT-IR studies.• The green synthesized metal nanoparticle has emerged at low cost, simpler and better choice than physical and chemical methods.• Green synthesized Se NPs were found to be almost spherical in shape with particle size around 40–90 nm, selenium has high purity and crystalline nature was identified using EDX and XRD.• The DPPH scavenging analysis of the amorphous Se NPs has significant antioxidant activity and serves as a potential antibacterial agent to treat diseases caused by bacteria.• Antiproliferative activity results suggest that Se NPs possess higher growth control against A549 lung carcinoma cancer cells (IC50 at 25 μg/ml) which indicated their potential in medical applications.• The photocatalytic study concludes that these Se NPs have efficiency to degrade MB under sunlight irradiation. Therefore, they can find application in water treatment plants and textile industries.

Selenium nanoparticles and micells are tools for tuberculosis prevention

The adjuvant properties of micelles of nonionic detergent and E. coli lipids, as well as of selenium nanoparticles, were studied in the course of immunization with antigens of the diagnostic tuberculin (). As the structural basis of micelles, a commercial non-ionic detergent Triton X-114 or Escherichia coli Б-5 lipids isolated from bacterial cells by Folch extraction were used. Particles of reduced selenium were obtained by reducing selenious acid with sodium thiosulfate in the presence of PPD. Micelles of lipid E. B-5 with PPD antigens were obtained by hydration of a dry film of lipids of the bacteria together with PPD The Triton X-114 micelles were prepared by dissolving the detergent in the PPD solution.&nbsp;The formation of antibodies against PPD and Mycobacterium bovis BCG cells was studied in immunization of white mice with these constructs in comparison with the PPD immunization, using the indirect dot-immunoassay method, as well as immunoturbodimetrically. Immunization of mice with E. coli B-5 lipid or Triton X-114 micelles bearing PPD leads to the formation of antibodies against tuberculin antigens higher than for immunization with PDD itself. Immunization with all drugs, including PPD, leads to the formation of antibodies that recognize M. bovis BCG cells, but the highest levels of antibodies are observed in the blood plasma of animals receiving lipid E. coli B-5 or Triton X-114 micelles. The obtained results indicate the possibility of using micelles and selenium nanoparticles as an adjuvant for immunization with mycobacterial antigens.

Open-framework sodium uranyl selenate and sodium uranyl sulfate with protonated morpholino-N-acetic acid

AbstractThe reaction of sodium N-morpholine acetate with selenic and sulfuric acid and uranyl nitrate results in the formation of two novel open-framework compounds, |Na(Hmfa)|[(UO2)2(SeO4)3(H2O)](H2O)2(NaUSe) and [Na2(SO3OH)(Hmfa)]|(UO2)(SO4)2| (NaUS), respectively. Despite identical synthetic procedures, sulfate structure dramatically differs from selenate compound. Their common feature is an open-framework featuring two-dimensional system of channels occupied by protonated morpholino-N-acetic acid species. Coordination of Na atoms is different. InNaUSe, [(UO2)2(SeO4)3(H2O)]2−layers are pillared by {Na2O8(H2O)2(Hmfa)2} complexes to form a microporous framework. InNaUS, UO7and SO4polyhedra of [(UO2)(SO4)2]2−chains share common oxygen atoms with Na-centered tetrameric complexes providing a three-dimensional integrity of the structure. Both of the compounds are characterized by IR spectroscopy.

Apoptosis and autophagy induction of Seleno-β-lactoglobulin (Se-β-Lg) on hepatocellular carcinoma cells lines

β-lactoglobulin is important fraction in bovine milk. Selenium is an essential nutrient element. The apoptosis and autophagy induction of Se-β-Lg combined selenic acid in β-lactoglobulin on Hep G2 and Hep 3B cells were investigated in this study. MTT assay showed Se-β-Lg inhibited cells viability. Annexin V-FITC/PI and PI staining indicated Se-β-Lg triggered cells apoptosis and cell cycle arrest. Western blot of caspase-cascade suggested Hep G2 and Hep 3B cells occurred irreversible extrinsic apoptosis. TEM and protein expression of LC3 indicated Se-β-Lg induced cells autophagy. Further explore found Se-β-Lg induced up-regulation of p53 and Fas/FasL in Hep G2 cells. Simultaneously, N-acetyl-L-cysteine, pifithrin-α, Z-VAD-FMK and 3-MA were used. These results further demonstrated Se-β-Lg triggered autophagy and receptor-related apoptosis via p53-mediated Fas/FasL pathway in Hep G2 cells and induced autophagy and p53/Fas-independent caspase activation in Hep 3B cells. Our research revealed that Se-β-Lg had potential to act as chemopreventive compounds in HCC therapy.

Phase I trial of selenium plus chemotherapy in gynecologic cancers

PurposePreclinical studies performed in our laboratory have shown that high-dose selenium inhibits the development of carboplatin drug resistance in an ovarian cancer mouse xenograft model. Based on these data, as well as the potential serious toxicities of supranutritional doses of selenium, a phase I trial of a combination of selenium/carboplatin/paclitaxel was designed to determine the maximum tolerated dose, safety, and effects of selenium on carboplatin pharmacokinetics in the treatment of chemo-naive women with gynecologic cancers. Correlative studies were performed to identify gene targets of selenium. MethodsChemo-naïve patients with gynecologic malignancy received selenious acid IV on day 1 followed by carboplatin IV and paclitaxel IV on day 3. A standard 3 + 3 dose-escalating design was used for addition of selenium to standard dose chemotherapy. Concentrations of selenium in plasma and carboplatin in plasma ultrafiltrate were analyzed. ResultsForty-five patients were enrolled and 291 treatment cycles were administered. Selenium was administered as selenious acid to 9 cohorts of patients with selenium doses ranging from 50 μg to 5000 μg. Grade 3/4 toxicities included neutropenia (66.7%), febrile neutropenia (2.2%), pain (20.0%), infection (13.3%), neurologic (11.1%), and pulmonary adverse effects (11.1%). The maximum tolerated dose of selenium was not reached. Selenium had no effect on carboplatin pharmacokinetics. Correlative studies showed post-treatment downregulation of RAD51AP1, a protein involved in DNA repair, in both cancer cell lines and patient tumors. ConclusionOverall, the addition of selenium to carboplatin/paclitaxel chemotherapy is safe and well tolerated, and does not alter carboplatin pharmacokinetics. A 5000 μg dose of elemental selenium as selenious acid is suggested as the dose to be evaluated in a phase II trial.

Assessing the Physicochemical Stability of a Compounded Neonatal Trace Element Solution.

Alberta Health Services (AHS) recommends the adoption of a new neonatal multi-trace element formulation containing zinc sulfate, copper sulfate, selenious acid and sodium iodide to be compounded internally in appropriate AHS pharmacies. The objective of this study was to assess the physicochemical stability of this formulation under commonly used storage conditions. Three batches of trace element solution were compounded by University of Alberta Hospital pharmacy staff using sterile compounding procedures. Appropriate amount of zinc sulfate (500 mg/mL), copper sulfate (40 mg/mL), selenious acid (4 mg/mL), sodium iodide (2 mg/mL) and sterile water for injection were mixed. Samples from each batch were divided in individual vials and syringes for each time point and kept protected from light either at room temperature (15-30°C) or fridge (2-8°C). Vial samples were also kept at room temperature for 12 h and then transferred to fridge. Vial samples were analyzed at time 0, 12 h, and 1, 3, 7, 9, 30, 60, 90 days for their physical appearance and pH, then centrifuged and assessed for the soluble zinc (atomic absorption), copper (atomic absorption), selenium (ICP-MS) and iodine (HPLC and ICP-MS) concentrations. Syringe samples were tested at time 0 and 12 h for element concentrations. Under all storage conditions, when stored in vials, samples' appearance, pH and soluble zinc, copper and selenium concentrations stayed within the USP acceptable limits up to 90 days. Iodine concentration was within the permitted limits only up to 7 days. The USP recommended HPLC method of iodine analysis seemed inadequate for this preparation and needed modifications, through frequent washing of the column with KI (2 %) solution. Samples kept in syringes at room temperature, showed lower than permitted concentration of Zn at 12h in this study. The AHS neonatal multi-trace element formulation seem to be physio-chemically stable up to 7 days in all three storage conditions when kept in vials. A decline in iodine concentration is seen after 7 days irrespective of storage conditions.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

In vitro assessment of bioavailability of selenium from a processed Japanese anchovy, Niboshi

Niboshi is a commonly used foodstuff that is processed from Japanese anchovy (Engraulis japonicus) in Japanese cuisine. It was previously demonstrated that Niboshi and its water extract contained highly bioavailable selenium for selenium deficient mice. In this study, we assessed the selenium bioavailability from the extract of the Niboshi, using cultured cells. The activity of selenium-dependent glutathione peroxidase (GPx) of rat dorsal ganglion cells and human cervical carcinoma cells incubated with selenium from the Niboshi extract was over 2 times of that of the extract-free control cells and comparable to that of cells incubated with selenious acid of the same selenium concentration. These results suggest that selenium from the Niboshi extract was utilized for synthesis of the selenoprotein. Such in vitro selenium bioavailability was consistent with our previous results of in vivo assessment in mice.

Abstract CT025: Phase I trial of selenium plus chemotherapy in gynecologic cancers

Abstract PURPOSE: The effectiveness of standard-of-care platinum-taxane chemotherapy in the treatment of patients with advanced gynecologic cancers is limited by the development of chemotherapy resistance in nearly all patients. Based on our preclinical findings that selenium, an essential trace element, inhibits the development of carboplatin drug resistance in an ovarian cancer mouse model, a phase I trial of a combination of selenious acid/carboplatin/paclitaxel was designed to determine the maximum tolerated dose (MTD) and safety of selenium administered with chemotherapy in chemo-naïve women with gynecologic cancers. In addition, the effects of selenium on carboplatin pharmacokinetics were evaluated in this group of patients, and correlative studies were performed to identify potential gene targets of selenium. METHODS: Patients with gynecologic malignancy not previously treated with chemotherapy received 50-5000 µg elemental selenium IV in the form of selenious acid on day 1 followed by carboplatin (cycle 1, AUC 5; subsequent cycles, AUC 6) IV and paclitaxel 175mg/m2 IV on day 3. A standard 3+3 trial design was used in the selenium dose escalation phase. Concentrations of selenium in plasma and carboplatin in plasma ultrafiltrate were analyzed. RNA expression in tumor specimens and breast and ovarian cancer cell lines were compared before and after treatment with selenium plus chemotherapy using the Human Exon 1.0 ST exon microarray platform. In addition, Western immunoblotting was performed to evaluate protein expression of RAD51AP1, a protein involved in DNA repair, in untreated MCF-7/Adr cells and MCF-7/Adr cells treated with selenium, carboplatin, and the combination of selenium and chemotherapy. RESULTS: Forty-five patients were enrolled and a total of 291 treatment cycles were administered. Grade 3/4 toxicities included neutropenia (66.6%), febrile neutropenia (2.2%), as well as pain (20.0%), infection (13.3%), neurologic (11.1%), and pulmonary adverse effects (11.1%). The MTD of elemental selenium was not reached. Selenium had no effect on carboplatin pharmacokinetics. In the subset of patients with stage III/IV ovarian cancer/fallopian tube/peritoneal cancer, median progression-free survival was 15 months; in those patients within this subset with measurable disease, 30%, 35%, and 23% experienced complete response, partial response, and stable disease, respectively. Correlative studies showed downregulation of RAD51AP1 by selenium plus chemotherapy in cancer cell lines as well as in tumors of patients treated within this clinical trial. CONCLUSION: Selenium in combination with carboplatin and paclitaxel is safe and does not affect carboplatin pharmacokinetics. It is possible that selenium-mediated downregulation of RAD51AP1 plays a role in circumventing the development of resistance to carboplatin/paclitaxel chemotherapy. A phase II study to further investigate these findings is underway. Citation Format: Mihae Song, Muthu N. Kumaran, Murugesan Gounder, Darlene Gibbon, Wilberto Nieves-Neira, Ami Vaidya, Mira Hellman, Michael P. Kane, Brian Buckley, Lorna Rodriguez-Rust. Phase I trial of selenium plus chemotherapy in gynecologic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT025.

Proteolytic Activity of Chymotrypsin Immobilized on Selenium Nanoparticles

Chymotrypsin was immobilized as a part of hybrid organo-inorganic nanocomplexes on selenium nanoparticles in the reduction reaction of selenious acid with ascorbic acid. Chymotrypsin stabilized the selenium nanoparticles in the solution. The spectral characteristics of synthesized nanocomplexes and the proteolytic activity of immobilized chymotrypsin were studied. It was shown that the immobilized enzyme had increased proteolytic activity in an alkaline medium.

Reduction of biselenites into polyselenides in interlayer space of layered double hydroxides

A selenous acid (H2SeO3) precursor was intercalated as biselenite (HSeO3−) ions into the interlayer gallery of carbonated magnesium aluminum layered double hydroxide (MgAl-LDH) in aqueous solution. Reduction reaction of selenous ions by aqueous hydrazine solution produced polyselenide intercalated LDHs which were consecutively exchanged with iodide through redox reaction under iodine vapor. The polyselenide containing LDHs adsorbed iodine vapor spontaneously and triiodide was incorporated in the interlayer space followed by formation of selenium polycrystalline phase. Two dimensional framework of MgAl-LDH is strong enough to resist against the reducing power of hydrazine as well as oxidation condition of iodine. The SEM data demonstrated that the shapes of LDH polycrystalline have little changed after the above redox reactions. The polyselenide and iodide LDH products were analyzed by XRD, Infrared and Raman spectra which strongly suggested the horizontal arrangement of polyselenide and triiodide in gallery space of LDHs.

Combination cancer treatment through photothermally controlled release of selenous acid from gold nanocages

Selenite, one of the inorganic forms of selenium, is emerging as an attractive chemotherapeutic agent owing to its selectivity in eradicating cancer cells. Here we demonstrate a new formulation of nanomedicine based on selenous acid, which is mixed with lauric acid (a phase-change material with a melting point around 43 °C) and then loaded into the cavities of Au nanocages. The Au nanocages can serve as a carrier during cell endocytosis and then as a photothermal agent to melt the lauric acid upon the irradiation with a near-infrared laser, triggering the swift release of selenous acid. The photothermal and chemo therapies can also work synergistically, leading to enhanced destruction of cancer cells relative to normal cells. Our systematic study suggests that the impaired mitochondrial function arising from the ROS generated through combination treatment is responsible for the cell death. This study offers an appealing candidate that holds great promise for synergistic cancer treatment.

Selenium supplementation in pediatric patients using parenteral nutrition: Is it time to do something?

To analyze the nutritional status of selenium and verify the effect of its supplementation in pediatric patients during 14 days of parenteral nutrition (PN). This is a series of cases with patients followed for two weeks while using PN. Data collection was performed at the beginning (T0), in the 7th (T1) and 14th days of PN (T2). The supplemented group received 2 µg/kg/day of selenous acid. Weight and height were measured for nutritional status assessment. Tests requested: plasma selenium, albumin, pre-albumin, C-reactive protein (CRP), total cholesterol and HDL-cholesterol. Fourteen (14) patients with inflammatory process and with low or very low weight for their ages were evaluated. In both groups (with and without supplementation), all patients had low selenium levels. Median plasma selenium concentrations were 17.4 µg/L (T0), 23.0 µg/L (T1) and 20.7 µg/L (T2). Increase and reduction of selenium occurred both in patients with high CRP and in those presenting normalization of this parameter. Lower plasma selenium levels have been detected since the start of the research and supplementation (2 µg/kg/day of selenous acid) was not to enough to approach the reference values.

Electrochemical behaviour of selenite ions in tartaric electrolytes

&lt;span lang="EN-GB"&gt;In recent years, a great interest has been emerged on electrochemical preparation of semiconductor films based on selenium. Therefore, a study of electrochemical reduction of selenium could be very important. In this work, the kinetics and mechanism of the electrochemical reduction of selenite ions on the Pt cathode have been studied in the electrolyte containing selenious and tartaric acids. The study shows that electroreduction of selenite ions from tartaric electrolytes proceeds in two stages. The effect of various factors on the cathodic reduction of selenium ions has also been studied. The effective activation energy was calculated using the polarization curves of the temperature dependence of the electroreduction process of selenite ions. It was established that the process of electroreduction under investigation is proceeding by mixed kinetics, at first by concentration and then by electrochemical polarization.&lt;/span&gt;

Unexpected Behavior of Np in Oxo-selenate/Oxo-selenite Systems.

A study of neptunium (Np) chemistry in the complex oxo-selenium system has been performed. Hereby, two sets of precipitation experiments were conducted, investigating the influence of the initial oxidation state of selenium using SeIVO2 and H2SeVIO4 with NpV in alkali nitrate solution, keeping the ratio of Np/Se constant. Surprising results were observed. Five novel neptunium and selenium bearing compounds have been obtained by slow evaporation from aqueous solution. The novel NpIV phase K4-x[Np(SeO3)4-x(HSeO3)x]·(H2O)1.5 (1) crystallizes in green-colored, plate-shaped crystals and was obtained by adding SeO2 and ANO3 to a NpV stock solution. Single-crystal X-ray diffraction reveals one-dimensional chain structures composed of square antiprismatic NpO8 polyhedra linked via four trigonal pyramidal SeO3 and HSeO3 units. Raman spectral analysis supports the presence of both selenite and hydroselenite due to the presence of corresponding modes within the spectra. The addition of selenic acid to a NpV stock solution resulted in the precipitation of elongated rose prisms of K2[(NpO2)2(SeO4)3(H2O)2]·(H2O)1.5 (2), Rb2[(NpO2)2(SeO4)3(H2O)2]·(H2O)2 (3) and K9[(NpO2)9(SeO4)13.5(H2O)6]·(H2O)12 (4) as well as light red plates of Cs2[(NpO2)2(SeO4)3] (5). To our knowledge, this is the first report of NpVI selenates. All four structures show two-dimensional layered structures with alkali cations acting as charge balancing counter cations. Hereby the layers of compounds 2 and 3 are found to be orientational geometric isomers. Distinctly different phenomena are made responsible for the phase formation within these systems. The kinetically driven process of NpV disproportionation led to the formation of the NpIV selenites in the SeIV-based system, whereas the oxidation of NpV by reduction of nitrate in acidic conditions is responsible for the formation of the NpVI selenates in the SeVI system. The influence of air oxygen is also discussed for the latter reaction.

Comparison of biological activities of selenium and silver nanoparticles attached with bioactive phytoconstituents: green synthesized using Spermacoce hispida extract

Selenium and silver nanoparticles (NPs) were synthesized using Spermacoce hispida aqueous leaf extract (Sh-ALE). The optimum condition required for the synthesis of Sh-SeNPs was found to be 30 mM selenious acid solution to Sh-ALE at the ratio of 4:46, pH 9, incubated at 40 °C for 10 min. On the other hand, for Sh-AgNPs the optimum condition was found to be 1 mM AgNO3 to the Sh-ALE solution at the ratio of 4:46, pH 8, incubated at 40 °C for 10 min. SEM analysis revealed that both the Sh-AgNPs and Sh-SeNPs are predominantly rod-shaped. Sh-SeNPs and Sh-AgNPs were found to possess concentration-dependent antioxidant activity. However, Sh-SeNPs showed potent anti-inflammatory property, antibacterial property and anticancer activity against human cervical cancer cell in comparison to Sh-AgNPs. Phytochemical analysis, FTIR and GC-MS analysis showed that various flavonoids, saponins and phenolic compounds present in Sh-ALE catalysed the formation of NPs. Also, GC-MS analysis revealed that Sh-SeNPs are capped by synaptogenin B and derivatives of apigenin, quinoline and quinazoline. The advantage of attachment of such phytoconstituents on Sh-SeNPs for its potent biological activity in comparison to Sh-AgNPs is evident in in vitro conditions.

Probing the Influence of Acidity and Temperature to Th(IV) on Hydrolysis, Nucleation, and Structural Topology.

Systematic control of the molar ratio between thorium hydroxides and selenic acid and their reaction temperature under hydrothermal conditions results in four novel thorium-based selenate complexes, namely, [Th8O4(OH)8(SeO4)6(H2O)16]·(SeO4)2·13H2O (Th-1), [Th8O4(OH)8(SeO4)8(H2O)13]·7H2O (Th-2), Th(OH)2(SeO4)H2O (Th-3), and Th3(SeO4)6(H2O)6·2.5H2O (Th-4), as well as the thorium mixed selenite selenate compound Th(SeO3)(SeO4) (Th-5). Smaller [H2SeO4]/[Th(IV)] ratio or lower temperature give rise to the formation of octameric [Th8(μ3-O)4(μ2-OH)8]16+ cores in Th-1/Th-2 and infinite [Th(μ2-OH)2H2O]2+ chains in Th-3, respectively. Increasing the [H2SeO4]/[Th(IV)] ratio or elevating the temperature generates a microporous (11.3 Å voids) open-framework Th-4, a monomeric thorium species without oxo/hydroxyl ligands, and a three-dimensional thorium structure Th-5. Formation of these compounds suggests that variables including acidity and temperature play a critical role in the hydrolysis and oligomerization of ThIV ions. Increasing acidity limits the deprotonation of water molecules and formation of nucleophilic hydroxo/oxo-aquo Th species, and high temperature appears to suppress the olation/oxolation hydrolysis reactions, which in both ways limit the formation of the thorium oligomers.

Crystal structure, vibrational spectra and DFT studies of hydrogen bonded 1,2,4–triazolium hydrogenselenate

The new hydrogen bonded molecular complex 1,2,4–triazolium hydrogenselenate (THS) is prepared by the reaction of 1H–1,2,4–triazole and selenic acid. This complex is stabilised by N–H⋯O and C–H⋯O hydrogen bonding and electrostatic attractive forces between 1H and 1,2,4–triazolium cations and hydrogen selenate anions. The XRD studies revealed that intermolecular proton transfer occur from selenic acid to 1H–1,2,4–triazole molecule, results in the formation of 1,2,4–triazolium hydrogenselenate which contains 1,2,4–triazolium cations and hydrogenselenate anions. The molecular structure of THS crystal has also been optimised by using Density Functional Theory (DFT) using B3LYP/cc–pVTZ and B3LYP/6–311++G** methods in order to find the whole characteristics of the molecular complex. The theoretical structural parameters such as bond length, bond angle and dihedral angle determined by DFT methods are well agreed with the XRD parameters. The atomic charges and thermodynamic properties are also calculated and analysed. The energies of frontier molecular orbitals HOMO, LUMO, HOMO–1, LUMO+1 and LUMO–HUMO energy gap are calculated to understand the kinetic stability and chemical reactivity of the molecular complex. The natural bond orbital analysis (NBO) has been performed in order to study the intramolecular bonding interactions and delocalisation of electrons. These intra molecular charge transfer may induce biological activities such as antimicrobials, antiinflammatory, antifungal etc. The complete vibrational assignments of THS have been performed by using FT–IR and FT–Raman spectra.