I2 System Research Articles

Gold carbonyl cations and beyond: homoleptic gold(I) complexes with P4 and P4S3 and the half-sandwich cation [Au(C6H6)(CO)

Oxidation of Au0 with the synergistic Ag+/0.5 I2 system in the commercial organic solvent 1,2,3,4-tetrafluorobenzene led to the perfluoroalkoxyaluminate salt of the [Au(CO)2]+ cation known from superacid chemistry. This [Au(CO)2]+ salt proved to be an excellent 'naked' Au+-synthon yielding complex salts with [Au(η2-P4)2]+, [Au(η1-P4S3)2]+ and half-sandwich [Au(η2-C6H6)(CO)]+ cation.

Evaluation of a New Real-Time Dosimeter Sensor for Interventional Radiology Staff.

In 2011, the International Commission on Radiological Protection (ICRP) recommended a significant reduction in the lens-equivalent radiation dose limit, thus from an average of 150 to 20 mSv/year over 5 years. In recent years, the occupational dose has been rising with the increased sophistication of interventional radiology (IVR); management of IVR staff radiation doses has become more important, making real-time radiation monitoring of such staff desirable. Recently, the i3 real-time occupational exposure monitoring system (based on RaySafeTM) has replaced the conventional i2 system. Here, we compared the i2 and i3 systems in terms of sensitivity (batch uniformity), tube-voltage dependency, dose linearity, dose-rate dependency, and angle dependency. The sensitivity difference (batch uniformity) was approximately 5%, and the tube-voltage dependency was <±20% between 50 and 110 kV. Dose linearity was good (R2 = 1.00); a slight dose-rate dependency (~20%) was evident at very high dose rates (250 mGy/h). The i3 dosimeter showed better performance for the lower radiation detection limit compared with the i2 system. The horizontal and vertical angle dependencies of i3 were superior to those of i2. Thus, i3 sensitivity was higher over a wider angle range compared with i2, aiding the measurement of scattered radiation. Unlike the i2 sensor, the influence of backscattered radiation (i.e., radiation from an angle of 180°) was negligible. Therefore, the i3 system may be more appropriate in areas affected by backscatter. In the future, i3 will facilitate real-time dosimetry and dose management during IVR and other applications.

Catalytic Asymmetric Iodoesterification of Simple Alkenes

AbstractCatalytic asymmetric iodoesterification of simple alkenes was achieved using a dinuclear zinc‐3,3′‐(R,S,S)‐bis(aminoimino)binaphthoxide (di‐Zn) complex. For iodoesterification using p‐methoxybenzoic acid, the N‐iodonaphthalenimide (NIN)‐I2 system was effective for producing iodoesters in a highly enantioselective manner. The synthetic utility of chiral iodo‐p‐methoxybenzoates was also demonstrated. The quartet of metal ionic bond, hydrogen bond, halogen bond, and π‐π stacking is harmonized on the single reaction sphere of di‐Zn catalyst for enabling the highly enantioselective catalytic asymmetric iodoesterification of simple alkenes for the first time.

Catalytic Asymmetric Iodoesterification of Simple Alkenes.

Catalytic asymmetric iodoesterification of simple alkenes was achieved using a dinuclear zinc-3,3'-(R,S,S)-bis(aminoimino)binaphthoxide (di-Zn) complex. For iodoesterification using p-methoxybenzoic acid, the N-iodonaphthalenimide (NIN)-I2 system was effective for producing iodoesters in a highly enantioselective manner. The synthetic utility of chiral iodo-p-methoxybenzoates was also demonstrated. The quartet of metal ionic bond, hydrogen bond, halogen bond, and π-π stacking is harmonized on the single reaction sphere of di-Zn catalyst for enabling the highly enantioselective catalytic asymmetric iodoesterification of simple alkenes for the first time.

Density Functional Theory Study of Defect Induced Ferromagnetism and Half-Metallicity in CaI2 Based Monolayer for Spintronics Applications

With the rapid advancement of electronics and spintronics industries, the demand for highly efficient materials has been increased for the application of high speed devices and circuits. In the recent past, Ca-based systems have been studied for superconducting properties. Using first-principles density functional theoretical calculations, we have investigated another Ca-based system (CaI2) for its half-metallic properties, which can be promising for ultrafast nonscattering transport. In the domain of spintronics, main group based half-metallic materials have attracted much attention due to their long spin-relaxation time. Here, in this study, we report for the first time ferromagnetism and half-metallicity in calcium iodide (CaI2) based materials with a wide spin-up gap of ∼3.84 eV. Such high spin-up gap in Ca-based half-metallic material is very promising since it can provide nonscattering transport. Among all, Ca0.67δ0.33I2 has a similar pattern to the most well established and thinnest magnet, CrI3 monolayer. Our further investigation predicts that the Ca0.89δ0.11I2 system has a ferromagnetic ground state with Curie temperature of ∼238 K (XY model), which is considerably higher than the reported CrI3 monolayer (45 K). Further to this, such system has a high magnetic anisotropy energy (∼14.11 meV), which indicates that it can prohibit spin fluctuation. Therefore, we report here that alkaline earth metal halide based magnetic materials can be promising for next generation spintronics devices.

Growth and Properties of Mn-Doped PbI2 Crystals

This paper presents an experimental study of the effect of doping with manganese on the vapor phase growth of lead(II) iodide crystals in a closed system and their properties. The manganese concentration in the grown crystals and the mass transport rate in the PbI2–I2 system are determined by the Mn concentration in the growth charge and the temperature of the source zone. We have obtained single crystals of the following morphological types: elongated ribbons, ribbons with sharp ends, plates, and their combinations and intergrowths. Doping with manganese has been shown to influence low-temperature (T = 5 K) photoluminescence spectra of PbI2.

Synthesis of Chiral Polyhydroxylated Benzimidazoles by a Tandem Radical Fragmentation/Cyclization Reaction: A Straight Avenue to Fused Aromatic-Carbohydrate Hybrids.

The synthesis of benzimidazole-fused iminosugars through a tandem β-fragmentation-intramolecular cyclization reaction is described. The use of the benzimidazole ring as the internal nucleophile and the use of phenyliodosophthalate (PhI(Phth)), a new metal-free and low toxic hypervalent iodine reagent, are the most remarkable novelties of this synthetic strategy. With this approach, we have demonstrated the usefulness of the fragmentation of anomeric alkoxyl radicals promoted by the PhI(Phth)/I2 system for the preparation of new compounds with potential interest for both medicinal and synthetic chemists.

Synthesis of (−)-elemoxide, a commercially important fragrance compound

(−)-Elemoxide, a fragrant compound was synthesised using commercially available elemol in four steps with overall yield of 32%. The cyclic ether skeleton was constructed via intramolecular hydroalkoxylation using I2 and PhSiH3 catalytic system. Also, intramolecular oxymercuration-demercuration was employed as an alternate approach for cyclization. The various regioselective strategies involving epoxidation of alkene, reduction of epoxide and intramolecular cyclization were the highlights of the work. The key intermediate diol serves as a versatile intermediate for the synthesis of elemoxide and elemene.

Quantum wave packet dynamics of the H + Li2 reaction at state-to-state level of theory

The time-dependent wave packet method with a second order split operator is employed to study the state-to-state resolved reaction dynamics of the H+Li2 system. The dynamics properties, such as reaction probability, integral cross-section, differential cross-section and the rovibrational state distribution of the product are fully calculated in the present work. Both forward and backward scattering signals peaked at two extreme angles, indicating that the insert reaction mechanism plays an important role and that the statistic model is highly suitable to assess the reaction dynamics H+Li2.

Study on a new wet flue gas desulfurization method based on the Bunsen reaction of sulfur-iodine thermochemical cycle

A novel wet flue gas desulfurization method based on the Bunsen reaction of sulfur-iodine (SI) thermochemical cycle was investigated in this paper. I2 and HI absorption system was utilized to remove SO2 from simulated coal-fired flue gas. The SO2 removal efficiency was about 98.8% when the I2 concentration was 25.6mmol/L. The influences of reaction temperature, initial SO2 concentration and the other flue gas components on SO2 removal were investigated, respectively. The absorption products were H2SO4 and HI, which could be easily separated by distillation. Compared with the traditional wet flue gas desulfurization (FGD) byproducts, such as gypsum or magnesium sulfate, H2SO4 has better commercial value and application prospect. Moreover, HI could be used as the raw material for the hydrogen production in the SI thermochemical cycle. In short, it is a promising technology for the SO2 removal and recycling from coal-fired flue gas.

Ultrasound-assisted synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzoxazoles, and related heterocycles

A sonochemical method for the synthesis of 2-aminobenzimidazoles and 2-aminobenzoxazoles, as well as chiral aminooxazolines and a chiral substituted quinazolin-5-one is reported. Using the Ph3P–I2 system in the presence of triethylamine as a desulfurization agent, monothioureas prepared in situ from the reaction of bis-nucleophiles with isothiocyanates underwent rapid cyclization to afford a variety of N-heterocyclic compounds in good to excellent yields under mild conditions.

Staff doses in fluoroscopically guided invasive diagnostic and interventional urology procedures

Introduction The number of fluoroscopically guided invasive diagnostic and interventional urology procedures is increasing during the last few years. This leads to higher staff doses in comparison with other radiology procedures. Purpose The aim of this study is to evaluate staff doses in fluoroscopically guided invasive diagnostic and interventional urology procedures. All the data were collected in Emergency Hospital “N. I. Pirogov” on an old fluorography unit with X-ray tube over the table. Materials and methods Staff doses for intravenous pyelogram (IVP), percutaneous nephrostomy (PN) and ureteral “double-J” stenting were estimated with the system RaySafe i2 . It contains four dosimeters, with a wireless connection to a real time display. The dosimeters were worn on the unprotected upper part of the body and measured the personal dose equivalent H p (10). In order to evaluate the dose of the eye lense in personal dose equivalent H p (3) two methods were used: thermoluminescent dosimetry and Monte Carlo simulations. Results The highest staff dose for PN and “double-J” is received by the urologist (116.7 μSv and 42.6 μSv, respectively), while for the IVP the radiographer has the highest exposure (20.7 μSv). First results for the dose of the eye lense show values of 1.63 mSv for left eye and 5.67 mSv for right eye. Each member of the medical staff was on a different position in respect to the X-ray tube and the patient which is the main reason for the differences in the staff doses. Conclusion The variations in the mean staff doses are mostly due to the interventions themselves, their complexity and the individual treatment of every patient. RaySafe i2 is very useful and educational system. It can be a helpful tool for decreasing radiation exposure to medical staff. Acknowledgement The authors would like to thank RaySafe for the kindly submitted for temporary use i2 system.

Sustainable AC/AC hybrid electrochemical capacitors in aqueous electrolyte approaching the performance of organic systems

Abstract A high energy hybrid AC/AC electrochemical capacitor has been realized in aqueous Li2SO4+KI electrolyte mixture. Owing to the redox processes associated with the 2I−/I2 system, the positive electrode operates in narrow potential range and displays high capacity. During prolonged potentiostatic floating at 1.6 V, the hybrid cell demonstrates remarkably stable capacitance and resistance. Analyses by temperature programmed desorption after floating at 1.6 V proved that oxidation of the positive AC electrode is prevented by the use of Li2SO4+KI, which enables the maximum potential of this electrode to be shifted below the water oxidation potential. When charged at 0.2 A g−1 up to U = 1.6 V, the hybrid cell displays a high capacitance of 75 F g−1 (300 F g−1 per mass of one electrode) compared to 47 F g−1 (188 F g−1 per mass of one electrode) for a symmetric cell in Li2SO4. At 0.2 A g−1 up to 1.6 V, the hybrid capacitor in Li2SO4+KI displays an energy density of 26 Wh kg−1 which approaches the energy density of 30.9 Wh kg−1 measured when the same carbon is implemented in a capacitor using TEABF4/ACN electrolyte and charged up to 2.5 V.

Influence of the iodide/iodine redox system on the self-discharge of AC/AC electrochemical capacitors in salt aqueous electrolyte

Self-discharge (SD) of AC/AC (AC=activated carbon) electrochemical capacitors in aqueous solutions of lithium sulfate (Li2SO4) and lithium sulfate+iodide salts (Li2SO4+KI or Li2SO4+LiI) was investigated at 24°C and −40°C after cell potential hold at values from 1V to 1.6V. At 24°C, the cells exhibit lower SD in Li2SO4+KI than in Li2SO4, owing to the redox activity of the 2I−/I2 system which drives the positive AC electrode to operate in narrow potential range and display lower potential drop than in Li2SO4. At −40°C, the capacitors exhibit comparable and reduced SD both in Li2SO4+LiI and Li2SO4, whatever the holding cell potential. Three-electrode cell experiments demonstrate that, at −40°C, hydrogen chemisorption is thermodynamically unfavored under negative polarization, while the activity of the 2I−/I2 redox system under positive polarization is only slightly reduced. As a consequence, the AC/AC cells in Li2SO4 exhibit a typical electrical double-layer performance at −40°C, whereas they still behave as hybrid ones in Li2SO4+LiI, with twice higher capacitance than in Li2SO4. The (Ui-Ut) vs t1/2 plots demonstrate that SD is essentially controlled by diffusion at −40°C, suggesting that it originates from bulkier hydrated ions. Overall, in the investigated temperature range, the AC/AC capacitors in Li2SO4+LiI demonstrate low self-discharge and high capacitance, while being able to operate up to 1.6V.

Fundamental study of a real-time occupational dosimetry system for interventional radiology staff

Real-time monitoring of the radiation doses received by interventional radiology (IR) staff has become highly desirable. However, occupational doses are rarely measured in real time, due to the lack of a feasible method for use in IR. Recently, the i2 system by RaySafe™ has been introduced to measure occupational exposure in IR in real time. The i2 system consists of several personal dosimeters (PDs) and a base station with a display and computer interfacing. We evaluated the fundamental performance (dose linearity, dose-rate dependence, angular dependence, batch uniformity and reproducibility) of the i2 system. The dose linearity of the i2 was excellent (R2 = 1.00) The i2 exhibited slight dose-rate dependence (~20%) at very high dose rates (250 mGy h−1). Little angular dependence (within 20%) was observed between 0° and ±45°, in either the vertical or horizontal direction. We also found that the PD was highly sensitive (about 200%) at angles behind it, e.g. 180°. However, this backscattered radiation is not a problem, in general, due to the placement of the i2 sensor (PD) on the lead apron. We conclude that the i2 system facilitates accurate real-time monitoring and management of occupational doses during IR.

Prediction of phase equilibria of HIx system using artificial neural network: Experimental verification

Thermochemical sulfur–iodine (SI) cycle is one of the promising technologies investigated for hydrogen production using solar and nuclear energy. The development and validation of a reliable thermodynamic model for the HIx mixture (HI–H2O–I2) encountered in the SI cycle have been identified as a central research issue to provide estimations on the HIx section energy demand.In this contribution, we develop an artificial neural network (ANN) model to predict the real time phase equilibrium behavior. For the binary HI–H2O system, the ANN model is constructed for a pressure up to 84 bar, while for the ternary HI–H2O–I2 system, the model describes the equilibrium behavior for a pressure up to 53 bar. The proposed models show their potential with a maximum relative deviation (RD) of about 2.5% and a root mean square percentage error (RMSPE) of within 0.9% for binary, and a maximum RD of 3.6% along with an RMSPE of 0.64% for ternary systems.

ChemInform Abstract: Synthesis of Platinum-Rich Al-Pt Compounds by Reactions in the Pt/AlI3/ I2 System.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Facile Method for the Synthesis of Vicinal Azidoiodides by the Reaction of the NaN3–I2 System with Unsaturated Compounds

A facile and efficient method was developed for the synthesis of vicinal azidoiodides in 62–77% yields by the reaction of sodium azide and iodine with unsaturated compounds in methanol, aqueous methanol, or the water–methanol–tetrahydrofuran solvent system. The reaction in Et2O or CHCl3 produced only vicinal diiodides.

Photoinduced charge transfer mechanism in PPV [poly(p-phenylinevinylene)] polymer: role of iodide species

The photophysical and photochemical behavior of poly(p-phenylinevinylene (PPV) polymers in different solvents (toluene and Triton X-100) and in thin form [PPV/optical transparent electrode (OTE)] has been investigated by emission and transient absorption spectroscopies. The absorption and emission studies strongly indicate the presence of dynamic quenching for PPV polymers in different solvents (toluene and Triton X-100) in the presence of LiI/I2. The fluorescence quenching of the PPV polymer by iodide obeys the linear Stern–Volmer equation for PPV/toluene/LiI system. The positive deviation from Stern–Volmer observed in PPV/Triton X-100/I2 system may be accounted for by the “quenching sphere of action model”. Emission studies indicated an increased conjugation length for PPV polymers on going from solution to the solid state. The emission of PPV was readily quenched by hole scavengers such as I− (LiI, I2). The photoinduced charge transfer to these hole scavengers was studied by laser flash photolysis. The transient absorption measurements confirm the formation of I− and subsequent formation of \(I^{{* - }}_{2} \) which has been reported for the first time for PPV/I2 system.

Thermodynamic Calculations and Growth of ZnSe Single Crystals by Chemical Vapor Transport Technique

A thermodynamic model has been proposed for the growth of ZnSe single crystals by the chemical vapor transport (CVT) method using iodine as the transporting agent. The optimum growth conditions for the growth of good quality ZnSe single crystals have been investigated theoretically using partial pressure values of I, I2, ZnI2, and Se2, which were calculated empirically at different growth temperatures and for different iodine concentrations, present inside the growth ampule. The diffusion-limited transport rates have also been calculated by taking into consideration the growth temperature, the ampule length, the total pressure present inside the ampule, and the partial pressures of ZnI2 at growth and source zones. The change in supersaturation ratio with respect to temperature and initial iodine concentration has also been calculated using this numerical model. The optimum growth temperature for the ZnSe−I2 system has been predicted from the theoretical results. Experiments were carried out for the growth...