Water-soluble Iron Research Articles

Bioinspired nonheme iron complex that triggers mitochondrial apoptotic signalling pathway specifically for colorectal cancer cells.

The activation of dioxygen is the keystone of all forms of aerobic life. Many biological functions rely on the redox versatility of metal ions to perform reductive activation-mediated processes entailing dioxygen and its partially reduced species including superoxide, hydrogen peroxide, and hydroxyl radicals, also known as reactive oxygen species (ROS). In biomimetic chemistry, a number of synthetic approaches have sought to design, synthesize and characterize reactive intermediates such as the metal-superoxo, -peroxo, and -oxo species, which are commonly found as key intermediates in the enzymatic catalytic cycle. However, the use of these designed complexes and their corresponding intermediates as potential candidates for cancer therapeutics has scarcely been endeavored. In this context, a series of biomimetic first-row transition metal complexes bearing a picolylamine-based water-soluble ligand, [M(HN3O2)]2+ (M = Mn2+, Fe2+, Co2+, Cu2+; HN3O2 = 2-(2-(bis(pyridin-2-ylmethyl)amino)ethoxy)ethanol) were synthesized and characterized by various spectroscopic methods including X-ray crystallography and their dioxygen and ROS activation reactivity were evaluated in situ and in vitro. It turned out that among these metal complexes, the iron complex, [Fe(HN3O2)(H2O)]2+, was capable of activating dioxygen and hydrogen peroxide and produced the ROS species (e.g., hydroxyl radical). Upon the incubation of these complexes with different cancer cells, such as cervical, breast, and colorectal cancer cells (MDA-MB-231, AU565, SK-BR-3, HeLa S3, HT-29, and HCT116 cells), only the iron complex triggered cellular apoptosis specifically for colorectal cancer cells; the other metal complexes show negligible anti-proliferative activity. More importantly, the biomimetic complexes were harmless to normal cells and produced less ROS therein. The use of immunocytochemistry combined with western blot analysis strongly supported that apoptosis occurred via the intrinsic mitochondrial pathway; in the intracellular network, [Fe(HN3O2)(H2O)]2+ resulted in (i) the activation and/or production of ROS species, (ii) the induction of intracellular impaired redox balance, and (iii) the promotion of the mitochondrial apoptotic signaling pathway in colorectal cancer cells. The results have implications for developing novel biomimetic complexes in cancer treatments and for designing potent candidates with cancer-specific antitumor activity.

NEW VITAMIN-MINERAL PREPARATION FOR PREVENTION OF OBSTETRIC PATHOLOGY OF ANIMALS «BIOTAN 3Z»

The article presents the vitamin and mineral preparation «Biotan 3Z" which includes micro- and macroelements in the form of water-soluble salts, namely Calcium, Phosphorus, Magnesium, Iron, Copper Manganese, Copper, Cobalt and Manganese. It also contains many vitamins (aspartic acid, glutamic acid, vitamin A, E, B1, PP) and essential amino acids - rich in methionine, lysine, arginine, histidine, tyrosine, phenylalanine, isoleucine, leucine, valine, cystine, tryptophan, glycine, proline, threonine and serine, which are necessary for the normal functioning of the body. Due to this veterinary drug the level of diseases of domestic animals decreases, their productive qualities increase. This drug accelerates the growth of animals. Vitamin and mineral preparation «Biotan 3Z" reduces the incidence and mortality of animals. Prevents diseases that originate from changes in housing conditions or occur against the background of metabolism or lack of vitamins and minerals.
 When using this drug in bitches, the biochemical and morphological parameters of the blood of these animals were analyzed. Significant changes in blood parameters such as erythrocytes, hemoglobin, hematocrit, total protein, before and after administration of the drug in various forms of manifestation have not been established. There was only a slight increase in erythrocytes from 6,6±0,2 thousand / ml to 7,8±0,4 thousand/ml, as well as a slight increase in hemoglobin from 120±3,8 g/l to 146±6,8 g/l. Vitamins and minerals contained in the fed drug had a positive effect on metabolism in the mother and fetus, as evidenced by changes in blood creatinine, which at 14 weeks before delivery was 127,6 μmol/l and on the first day of delivery in the experimental group increased to 135.8 μmol/l.
 The addition of a vitamin-mineral preparation to the main diet in some way affected the metabolism and biochemical composition of the blood of the bitches of the experimental group. It was expressed by an increase in the physiological limits of glucose, total protein, albumin, creatinine, cholesterol, total calcium, inorganic phosphorus and a decrease in globulins, bilirubin and AST. The concentration of urea, triglycerides and LF activity almost did not change.
 Feeding of vitamin-mineral preparation «Biotan 3Z» to bitches before childbirth affected the content in the blood of experimental animals of total calcium and inorganic phosphorus, the concentration of which increased by 0,2 mmol / l compared to baseline, and 0,2 and 0,3 mmol/l – with the control group after the experiment. Vitamin and mineral preparation «Biotan 3Z» is of interest for veterinary medicine and therefore it is advisable to continue its further clinical study.

An Open Gate for High-Density Metal Ions in N-Doped Carbon Networks: Powering Fe–N–C Catalyst Efficiency in the Oxygen Reduction Reaction

Non-noble metal catalysts for the oxygen reduction reaction (ORR) showing catalytic activity comparable or even superior to that of the benchmark Pt/C are highly attractive systems for the development of a mature fuel cell technology. Fe–N–C moieties exhibit an optimal performance in the ORR although a synthetic strategy for their production still remains a challenging matter of catalysis and materials science. Herein, an original and general protocol for the preparation of high-density and discrete Fe–N–C-based single-atom catalysts has been proposed starting from cheap and food-grade raw components. The rational combination of chelating citrate ions with the ancillary monodentate thiocyanate (SCN–) ligand has established an “open gate” for water-soluble iron ions to be accommodated in the form of Fe–N–C moieties within the final C–N networks. Although recent findings in the field of electrocatalysis have pointed out the often beneficial synergistic action between isolated and metallic iron species or iron carbides and their protecting C–N shells, the poor selectivity on the nature of the final Fe species in N-doped C-networks remains a matter of debate and does not shed light on the effective nature of the active species in the process. The highly metal-loaded catalysts in the form of highly dispersed Fe–N–C moieties prepared with the synthetic protocol described in the paper have been tested as electrocatalysts in the ORR, showing electrocatalytic performance under an alkaline environment that ranks among the highest reported so far for related Fe single-atom catalysts (Fe-SACs) of the state-of-the-art.

Quantitative Analysis of Iron Bound to Humic Substances in Surface Water

Water-soluble iron species in surface water are predominantly composites of Fe(III) and natural organic matter (Fe(III)NOM), such as fulvic acid and humic acid (HA). Fe(III)NOM can promote the growth of microorganisms and plants; therefore, it has significant impact on aquaculture and agriculture businesses. In this paper, a simple method of concurrent pretreatment and colorimetry by using deferoxamine (DFO), L-ascorbic acid, and dye nanoparticle-coated test strip (DNTS) for Fe(II) has been proposed for the on-site and direct detection of Fe(III)NOM in surface water. DFO, well-known as a siderophore, shows sufficient intake ability of Fe(III) (Fe(III)DFO K: 1031) from Fe(III)NOM, but unfortunately it interfered with the color detection of Fe(II) with DNTS loading bathophenanthroline sulfonate. However, the addition of a large excess of L-ascorbic acid and the following pH decrease certainly solved the problem by decomposition of the Fe(III)DFO complex and the following reduction, thereby causing a color change corresponding to the Fe concentration. A quantitative analysis of Fe(III)HA in the range from 15 ppb to 1 ppm has been demonstrated to be surely successful by a comparison with two calibration curves of Fe(II) and Fe(III)- humic acid.

A method for liquid spectrophotometric measurement of total and water-soluble iron and copper in ambient aerosols

Abstract. Determination of transition metals in ambient aerosols is important due to their toxicity to human health. However, the traditional measurement techniques for metal analysis are often costly and require sophisticated instruments. In this study, we developed and verified relatively low-cost liquid spectrophotometric methods for the measurements of iron (Fe) and copper (Cu), the two most abundant transition metals in ambient fine particulate matter (PM2.5). For Fe analysis, we utilized a ferrozine-based colorimetric method, which has been frequently used for water-soluble (WS) Fe determination, and further extended this approach for the measurement of total Fe (water-soluble + water-insoluble). In this method, Fe is quantified through the formation of a light-absorbing ferrozine–Fe(II) complex (absorbance at 562 nm). A similar colorimetric method, which forms a bathocuproine–Cu(I) complex absorbing light at 484 nm, was developed and examined for measurement of WS and total Cu. These methods were applied to 24 h integrated filter samples collected in urban Atlanta. Based on PM2.5 ambient aerosols, total and water-soluble Fe and Cu concentrations were in good agreement with inductively coupled plasma mass spectrometry (ICP-MS) measurements (slopes 1.0±0.1, r2>0.89). The water-soluble components, operationally defined as those species in the aqueous filter extract that pass through a 0.45 µm filter, were further characterized by ultrafiltration, which showed that roughly 85 % of both the Fe and Cu in the water-soluble fraction was composed of species smaller than nominally 4 nm.

Iron nanoparticles as a promising compound for food fortification in iron deficiency anemia: a review.

Iron deficiency anemia (IDA) is a global health concern that is affecting all age groups significantly. Among many of the existing methods, the fortification of foods with iron salts is the best and most cost-effective strategy for targeting large-scale populations to provide nutritional security. The fortification of foods with iron salts is a challenging task because most iron complexes (ferrous sulfate, ferrous chloride) used in fortification are highly water-soluble, which impart unacceptable organoleptic changes in food vehicles and also causes gastrointestinal problems. However, insoluble iron salts (ferric pyrophosphate) do not cause unacceptable taste or color in food vehicles but low bioavailable. Nanosized iron salts can overcome these concerns. The particle size of iron salts has been reported to play an important role in the absorption of iron. Reduction in the particle size of iron compounds increases its surface area, which in turn improves its solubility in the gastric juice leading to higher absorption. Nanosized iron compound produces minimal organoleptic changes in food vehicles compared to water-soluble iron complexes. Thus nanosized iron salts find potential applications in food fortification to reduce IDA. This paper focuses on providing a complete review of the various iron salts used in IDA, including their bioavailability, the challenges to food fortification, the effects of nanosized iron salts on IDA, and their applications in food fortification. Graphic abstractFortification of foods with water-soluble Fe salts imparts unacceptable organoleptic changes in food vehicle and adverse impact on health. However, insoluble iron salts do not cause unacceptable taste or color in food vehicles but low bioavailable. Using Nano-sized iron compound produces minimal organoleptic changes in food vehicles compared to changes produced by water-soluble iron complexes, improves Fe absorption in the gastrointestinal tract and does not cause any health issues.

Use of the Kano model and sensory evaluation in the development of an iron supplement for women

AbstractThe study presents an alternative for the preparation of questions using the Kano model to evaluate the presentation of a powdered, water‐soluble supplement. The results were used to develop a formulation containing chelated Fe‐peptides for women. The experiment was carried out in two steps: (a) an online survey to determine the satisfaction with the powdered iron supplement in relation to other presentations, and the flavor preference, (b) sensory evaluation of the formulations developed. A total of 364 replies were collected in the online survey, which indicated indifference with respect to satisfaction for the use of a powdered, water‐soluble product as compared to pills, drops, and syrups. The flavors preferred were: lemon (46.6%), orange (40.9%), chocolate and red fruits (32%). The sensory test (n = 121) of the three formulations (strawberry, tangerine, and chocolate) containing 14 mg Fe2+ per sachet, validated the tangerine flavor as the most accepted and chocolate as rejected by the consumers.Practical ApplicationsIron supplements do not have very attractive flavors and have an unpleasant metallic aftertaste. Thus, in order to present a new type of supplement still unavailable on the market, the use of a comprehensive approach making use of methods such as the Kano model and a sensory evaluation, could help elucidate this question. The Kano model is an efficient tool used to evaluate attributes and allows one to obtain other information about consumer desires in both explicit and implicit ways. However, the application of the Kano model for attributes with three or more levels has been little explored. Thus, the present study presents an application of this model with the use of direct questions for an attribute with four levels, and the application of sensory tests that allow one to direct and optimize product development. The analysis of the information obtained contributed to the development of a sensorially acceptable powdered, water soluble iron supplement.

Accurate and sensitive analytical method for trace iron determination in clove tea and tap water samples by slotted quartz tube-flame atomic absorption spectrometry after its preconcentration with supramolecular solvent-based liquid-phase microextraction

A green supramolecular solvent-based liquid-phase microextraction (SUPRAs-LPME) strategy was developed and used for the preconcentration of iron in clove tea and tap water samples at trace levels. Complex formation occurred between the iron and a Schiff base ligand obtained from 5-bromosalicylaldehyde and o-phenylenediamine reaction, and the coordinate complex formed was extracted to supramolecular solvent phase. Limit of detection and quantification values was found as 4.3 and 14.2 μgL−1, respectively, under the optimized conditions. When the analytical performance values obtained with SQT-FAAS, SUPRAs-LPME-FAAS and SUPRAs-LPME-SQT-FAAS are compared with FAAS, enhancements in detection power based on the LOD comparisons were calculated as 1.8, 31.4 and 65.8 times, respectively. The presented method was successfully applied to the determination of water-soluble iron in real clove tea in addition to tap water samples at trace levels, and the percent recoveries were obtained as 94.7–103.0% and 96.9–107.6%, respectively.

A VARIABILIDADE AMBIENTAL INFLUENCIA A COMPOSIÇÃO E BIOMASSA FITOPLANCTÔNICA DE UM RESERVATÓRIO NEOTROPICAL

Phytoplankton is an important model of the aquatic environments functioning, responding directly to environmental variability in space and time. Therefore, represents an excellent tool for the monitoring of reservoirs, which comprise highly heterogeneous ecosystems longitudinally, influencing the structure and distribution of phytoplankton species. The objective of this study was to investigate the variation in the composition and biomass of the phytoplankton in a reservoir in the Goiás state, Brazil, and how these organisms respond to environmental variability along the reservoir spatial extent in dry and rainy periods. The phytoplankton and environmental variables were collected during one dry period and other rainy, over seven sampling sites, distributed in the regions downstream of the dam, lacustrine, intermediate and lotic of the reservoir. The composition and biomass of the phytoplankton community were measured as a response to the spatial and temporal environmental variability. We recorded a spatio-temporal variation in water temperature, light, nutrients, and phytoplankton biomass. Cyanobacteria had the highest biomass in the lacustrine and intermediate regions, while diatoms in the lotic region, in both periods. The highest phytoplankton total biomass was recorded in rainy period. We recorded a clear relation between the phytoplankton biomass and the environmental variability, being that water temperature, turbidity and soluble iron the ones that showed the biggest influence on the biomass structure. Thus, the composition and biomass of the phytoplankton community can be important metrics of reservoirs functioning and, therefore, the phytoplankton study in these ecosystems it's of interest in their monitoring, since reservoirs have great ecological, economic or public health relevance

Surface color changes of oak (Quercus alba L.) treated with dopamine and iron ion compounds by acceleration of temperature–humidity condition

To change the surface color of oak (Quercus alba L.) to dark and grey, the water-soluble iron ion compounded dopamine solution was applied and accelerated in temperature–humidity condition. The colorimetric parameters before and after treatment were measured and X-ray photoelectron spectra were carried out for a further understanding. The results showed that iron ions and the compounds can significantly cause color changes to the oak, while the compounds treated groups seemed more uniform. With increasing concentration of the colorants, the color change was more obvious. During acceleration in temperature–humidity condition, the oxidation occurred, which further caused color change to oak. However, different oxidation reactions might occur between iron ions and compounds treated groups. The compounds system was more sensitive to temperature–humidity condition. Thus, the color difference was the highest. In a word, this treatment was effective considering the coloring effect and safety process.

Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands.

The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S, etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.

Study of the structure and morphology of carbon sorbents

The paper presents the results of a study of the morphology of carbon sorbents from Kuzbass coal. Carbon sorbents were obtained by chemical activation of the initial coal with potassium hydroxide at a temperature of 800 °C and a KOH/coal ratio of 1 g/g. It was shown that alkaline activation has no significant effect on the ash content of the obtained carbon sorbents. The elemental composition of the obtained carbon sorbents practically does not differ and remains constant when the elemental composition of the initial coal changes. The morphology of the surface of the initial coal and sorbents was studied by the SEM method, and the different nature of the surface of carbon sorbents based on coal was shown. For carbon sorbents from bituminous coals of low stages of metamorphism, a spongy structure is characteristic, for carbon sorbents from bituminous coals of high stages, it is layered. The physicochemical characteristics of carbon sorbents were determined. A study was carried out for the content of total and water-soluble iron for the amount of water-soluble ash.

Effect of nano iron oxide application on iron availability in calcareous vertisols

Incubation studies on dynamics of applied nano iron oxides in calcareous Vertisol was conducted for a period of 60 days at department of Soil Science and Agricultural Chemistry, University of Agricultural Sciences, Dharwad. The results revealed that, DTPA iron in soil decreased with advancement in period of incubation. Highest DTPA extractable iron (6.87, 5.97, 4.89 and 4.74 mg kg-1 at 15, 30, 45 and 60 DAI, respectively) and water soluble iron (1.59, 1.81, 1.92 and 1.72 mg kg-1 at 15, 30, 45 and 60 DAI, respectively) was recorded in the treatment receiving nano Fe2O3 @ 2.5 mg kg-1mixed with FYM. The water soluble iron increased in all the treatments up to 45 DAI and thereafter, decreased. The treatments which received iron oxide formulations chelated with FYM recorded higher DTPA extractable and water soluble iron than their respective unchelated ones at all the concentration levels. Between the sizes, the nanoparticles having the size < 50 nm were found better than the size range of particles between 50 - 100 nm in maintaining soil DTPA iron and water soluble iron status at all concentration ranges throughout the incubation period.

Fine Particle Iron in Soils and Road Dust Is Modulated by Coal-Fired Power Plant Sulfur.

Transition metal ions, such as water-soluble iron (WS-Fe), are toxic components of fine particles (PM2.5). In Atlanta, from 1998 to 2013, a previous study found that WS-Fe was the PM2.5 species most associated with adverse cardiovascular outcomes. We examined this data set to investigate the sources of WS-Fe and the effects of air quality regulations on ambient levels of WS-Fe. We find that insoluble forms of iron in mineral and road dust combined with sulfate from coal-fired electrical generating units were converted into soluble forms by sulfate-driven acid dissolution. Sulfate produced both the highly acidic aerosol (summer pH 1.5-2) and liquid water required for the aqueous phase acid dissolution, but variability in WS-Fe was mainly driven by particle liquid water. These processes were more pronounced in summer when particles were most acidic, whereas in winter the relative importance of WS-Fe from combustion emissions increased. Although WS-Fe constituted a minute fraction of PM2.5 mass (0.15%), the WS-Fe-PM2.5 mass correlation was high (r = 0.67) and may be explained by these formation routes, which, in part, could account for observed associations between PM2.5 mass and adverse health seen in past studies. Similar processes are expected in many regions, implying that these unexpected benefits from coal-burning reduction may be widespread.

Mono Dispersable Water-Soluble Iron Sulfide Nanoclusters: Synthesis, Characterization and Catalytic Application for Highly Efficient Synthesis of Xanthene Derivatives

In this manuscript, we have synthesized Iron sulfide nanoclusters (FeSNCs) by precipitation reaction between ferric chloride (FeCl3 · 6H2O) and thiourea with sodium borohydride (NaBH4) as a reducing agent at room temperature in water. These nanoclusters are synthesized within two minutes. The morphology and size of these synthesized FeSNCs were confirmed from transmission electron microscopy (TEM) and scanning electron microscopy (SEM). TEM and SEM data showed that the average diameters of these FeSNCs are around 70 nm. The Power X-ray diffraction (XRD) patten of the FeSNCs clearly showed the crystalline nature of these nanoclusters. Vibrating sample magnetometer (VSM) experiment showed that these nanoclusters are ferromagnetic in nature having high magnetization (20 emu/g). The nitrogen adsorption isotherm of FeSNCs confirmed the porous nature. These well characterized FeSNCs were further utilized as a catalyst for the synthesis of 9-aryl-1,8-dioxooctahydroxanthenes and 14-substituted-14H-dibenzo[a, j] xanthene derivatives. It is observed that the catalytic activities of FeSNCs are much better than the other reported heterogeneous and homogeneous catalysts. After completion of the reaction, FeSNCs are separated from the reaction mixture with the help bar magnet, washed and reused for the next catalytic reaction. Current method offers several advantages over other reported methods such as excellent yields, short reaction times, simple reaction procedure, and reusability of the catalyst upto five times without any significant loss in its activity.

Calixarenes functionalised water-soluble iron oxide magnetite nanoparticles for enzyme immobilisation

ABSTRACT In this study, we first used water-soluble iron oxide nanoparticles for Candida rugosa lipase immobilisation. Moreover, two new complexation phenomena of the prepared water-soluble Fe3O4 nanoparticles with an enzyme might address interesting results in terms of enzyme activity and stability in typical enzymatic reactions. The catalytic activity on pH and temperature dependence, and reusability of the immobilised lipases ( p-SCX4-NP-E and p-SCX8-NP-E) were also investigated with the hydrolysis reaction of p-nitrophenyl palmitate (p-NPP). The results show that the highest catalytic affinities for p-SCX4-NP-E and p-SCX8-NP-E were obtained at pH 5.0 and pH 7.0, respectively.

Water-soluble iron emitted from vehicle exhaust is linked to primary speciated organic compounds

Abstract. Iron is the most abundant transition element in airborne particulate matter (PM), primarily existing as Fe(II) or Fe(III). Generally, the fraction of water-soluble iron is greater in urban areas compared to areas dominated by crustal emissions. To better understand the origin of water-soluble iron in urban areas, tailpipe emission samples were collected from 32 vehicles with emission certifications of Tier 0 low emission vehicles (LEV I), Tier 2 low emission vehicles (LEV II), ultralow emission vehicles (ULEVs), super-ultralow emission vehicles (SULEVs), and partial-zero emission vehicles (PZEVs). The components quantified included gases, inorganic ions, elemental carbon (EC), organic carbon (OC), total metals, and water-soluble metals. Naphthalene and intermediate-volatility organic compounds (IVOCs) were quantified for a subset of vehicles. The IVOCs quantified contained 12 to 18 carbons and were divided into three subgroups: aliphatic, single-ring aromatic (SRA), and polar (material not classified as either aliphatic or SRA). Iron solubility in the tested vehicles ranged from 0 % to 82 % (average 30 %). X-ray absorption near-edge structure (XANES) spectroscopy showed that Fe(III) was the primary oxidation state in 14 of the 16 tested vehicles, confirming that the presence of Fe(II) was not the main driver of water-soluble Fe. The correlation of water-soluble iron with sulfate was insignificant, as was correlation with every chemical component except naphthalene and some C12–C18 IVOCs with R2 values as high as 0.56. A controlled benchtop study confirmed that naphthalene alone increases iron solubility from soils by a factor of 5.5 and that oxidized naphthalene species are created in the extract solution. These results suggest that the large driver in water-soluble iron from primary vehicle tailpipe emissions is related to the organic composition of the PM. We hypothesize that, during the extraction process, specific components of the organic fraction of the PM are oxidized and chelate the iron into water.

Detection of hydroxyaromatics in a superior manner by a water soluble fluorescent iron-complex

The fluorescence detection of phenolic compounds and a way to crystallize out iron ions and phenolic compounds from aqueous solution are investigated. A water soluble iron complex (N,N'-bis(3-imidazolium-1-ylpropyl)naphthalenediimide)di[bis-2,6-pyridinedicarboxylateferrate] (1) having a cationic part as fluorescent species, where the cationic fluorescent part is not in direct contact with the paramagnetic iron (3+) ion is used to detect phenolic compounds in water. The iron-complex also forms inclusion complex with phenolic compounds providing a conceptual means to remove the phenolic pollutants from solution. The fluorescence emission of the complex in aqueous solution is quenched by various hydroxyaromatic compounds and provides means for their detection. The detection limits to detect common phenolic compounds are in the range 0.39 μM to 0.66 μM. The quenching constant for 2,4,6-trinitrophenol by the complex is 3.98 × 106 mol−1 which is at par with several other good quenchers used for such detection. Structural study on the inclusion complexes showed selective formation of 1:1 inclusion complex of 1 with 1,4-dihydroxybenzene, but a 1:2 inclusion complex with phenolic compounds namely 1,3,5-trihydroxybenzene, 3-nitrophenol, 4-nitrophenol. The structural study and the conformational adjustments of the inclusion complexes are presented. The formation of different inclusion complexes in one-pot provided a means to crystallize out iron ions and nitrophenols simultaneously.

Continuous growth phenomenon for direct synthesis of monodisperse water-soluble iron oxide nanoparticles with extraordinarily high relaxivity.

The direct synthesis of highly water-soluble nanoparticles has attracted intensive interest, but systematic size control has not been reported. Here, we developed a general method for synthesizing monodisperse water-soluble iron oxide nanoparticles with nanometer-scale size increments from 4 nm to 13 nm in a single reaction. Precise size control was achieved by continuous growth in an amphiphilic solvent, diethylene glycol (DEG), where the growth step was separated from the nucleation step by sequential addition of a reactant. There was only one reactant in the synthesis and no need for additional capping agents and reducing agents. This study reveals the "living growth" character of iron oxide nanoparticles synthesised in an amphiphilic solvent. The synthetic method shows high reproducibility. The as-prepared iron oxide nanoparticles are extremely water soluble without any surface modification. Surprisingly, the synthesized 9 nm iron oxide nanoparticles exhibit extremely high transversal and longitudinal relaxivities of 425 mM-1 s-1 and 32 mM-1 s-1 respectively, which is among the highest transversal relaxivity in the literature for sub-10 nm spherical nanoparticles. This study will not only shed light on the continuous growth phenomenon of iron oxide nanoparticles in an amphiphilic solvent, but could also stimulate the synthesis and application of iron oxide nanoparticles. The continuous growth method could be further extended to other materials for the controlled synthesis of water-soluble nanoparticles.

A 19F-MRI probe for the detection of Fe(ii) ions in an aqueous system.

Iron deposits are often observed in the brains of patients with neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. This study outlines the development of F-Nox-1 as the first example of a 19F-MRI probe that can selectively detect Fe(ii) in aqueous solutions. The use of tetrafluoro-p-phenylenediamine (TFPDA) as a 19F signal emitter with an Fe(ii)-selective chemical switch, based on our previously reported N-oxide chemistry, yielded a readout of a symmetry-dependent 19F signal change in response to Fe(ii). The addition of Fe(ii) ions to F-Nox-1 triggered a 19F signal change, both in the chemical shift and signal intensity, and the response was highly selective to Fe(ii) over other biologically relevant metal ions. The probe could also detect Fe(ii) in serum containing various biological contaminants by 19F magnetic resonance imaging (19F-MRI). Imaging of soluble Fe(ii) species, which is the major component of water-soluble iron species, by 19F-MRI will potentially enable the direct monitoring of the elevation of Fe(ii) levels prior to the formation of iron deposits, which is a potential risk factor for neurodegenerative diseases.