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1.
Dr. Dennis Rottschäfer Beate Neumann Dr. Hans-Georg Stammler Dr. Tetiana Sergeieva Dr. Diego M. Andrada Dr. Rajendra S. Ghadwal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):3055-3064
Herein, we report the first 1,4-diphosphinine-1,4-diide compound [(ADCPh)P]2 ( 5-Ph ) (ADCPh=PhC{(NDipp)C}2; Dipp=2,6-iPr2C6H3) derived from an anionic dicarbene (ADCPh) as a red crystalline solid. Compound 5-Ph containing a 16π-electron planar fused-tricyclic ring system was obtained by the 4e reduction of [(ADCPh)PCl2]2 ( 4-Ph ) with Mg (or KC8) in a quantitative yield. Experimental and computational results imply that the central 8π-electrons C4P2 ring of 5-Ph , which is fused between two 6π-electrons C3N2 aromatic rings, is antiaromatic. Thus, each of the phosphorus atoms of 5-Ph has two electron-lone-pairs, one in a p-type orbital is in conjugation with the C=C bonds of the C4P2 ring, while the second resides in a σ-symmetric orbital. This can be shown with the gold complex [(ADCPh)P(AuCl)2]2 ( 6-Ph ) obtained by reacting 5-Ph with (Me2S)AuCl. A mixture of 5-Ph and 4-Ph undergoes comproportionation in the presence of MgCl2 to form the intermediate oxidation state compound [(ADCAr)P]2(MgCl4) ( 7-Ph ), which is an aromatic species. 相似文献
2.
Emilia Gîlcă Andrada Măicăneanu Petru Ilea 《Central European Journal of Chemistry》2014,12(8):821-828
The aim of this study was to compare several anion exchangers and to investigate the capacity of Amberlite IRA410 to remove zinc as chloride [ZnCl3]? from hydrochloric solutions (1 M). Influence of the process parameters such as stirring rate, resin quantity and zinc initial concentration over the removal process, was considered. The highest experimental ionic exchange capacity between the considered anionic exchangers, in the same working conditions (500 rpm, 5 g resin and 500 mg L?1), was obtained for Amberlite IRA410, 8.34 mg g?1. With an increase of zinc ions concentration, ionic exchange capacity increased up to 19.31 mg g?1 (1100 mg L?1). The experimental data were analysed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The results were also analyzed using sorption kinetics models, pseudo-first-, pseudo-second-order, intra-particle and film diffusion models. From the Dubinin-Radushkevich and Temkin isotherm models the mean free energy and heat of sorption were calculated to be 7.45 kJ mol?1, respectively 1×10?4 kJ mol?1, which indicates that zinc sorption is characterized by a physisorption process. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model. 相似文献
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We obtain some general results on Sasakian Lie algebras and prove as a consequence that a (2n + 1)-dimensional nilpotent Lie group admitting left-invariant Sasakian structures is isomorphic to the real Heisenberg group H 2n + 1. Furthermore, we classify Sasakian Lie algebras of dimension five and determine which of them carries a Sasakian α-Einstein structure. We show that a five-dimensional solvable Lie group with a left-invariant Sasakian structure and which admits a compact quotient by a discrete subgroup is isomorphic to either H 5 or a semidirect product ? ? (H 3 × ?). In particular, the compact quotient is an S 1-bundle over a four-dimensional Kähler solvmanifold. 相似文献
4.
Wolfgang Petz Diego M. Andrada Markus Hermann Gernot Frenking Bernhard Neumüller 《无机化学与普通化学杂志》2017,643(16):1096-1099
The formation and X‐ray structure analysis of the PtIV complex [(CH2C{PPh2C6H4}2)PtI2] is reported. The molecule possesses the orthometalated ligand (PPh3)2C→CH2, which serves via its C2 fragment as an unprecedented four‐electron σ donor. 相似文献
5.
Pinto FG Andrada D Magalhães CG Nunes BR de Amorim FR Franco MB Saint'pierre TD da Silva JB Curtius AJ 《Analytical and bioanalytical chemistry》2005,383(5):825-832
Different chemical modifiers for use with electrothermal atomic absorption spectrometry (ET AAS) were investigated in relation
to determining the selenium in human urine samples. The samples were diluted in a solution containing 1% v/v HNO3 and 0.02% m/v cetyltrimethylammonium chloride (CTAC). Studying the modifiers showed that the use of either Ru or Ir as the
permanent modifier gave low sensitivity to Se and the peak shape was very noisy, while Zr or Rh gave no peak at all. The same
occurred when Zr was used in solution. For mixtures of permanent modifiers, Ir plus Rh or Zr plus Rh gave very low sensitivity,
Zr plus Rh with co-injection of Ir in solution was also not efficient, Zr plus Rh in solution gave good sensitivity, but the
best results were obtained with a mixture of Zr and Rh as the permanent modifier and co-injection of Rh in solution. Using
this last modifier, the following dilutions with the HNO3 and CTAC were studied: 1:1, 1:2, 1:3 and 1:4. The best dilution was 1:1, which promoted good sensitivity and a more defined
peak shape and made it possible to correct for the background using a deuterium arc lamp. Under these conditions, a characteristic
mass of 26±0.2 pg was obtained for Se in aqueous solution. Six certified urine samples were analyzed using matrix matching
calibration and the measured concentrations were in agreement with the certified values, according to a t-test at the 95%
confidence level. Recovery tests were carried out and the recoveries were in the range 100–103%, with relative standard deviation
better than 9%. The limit of detection (LOD, 3 sd, n=10) was 3.0 μg L−1 in the sample. The treated graphite tube could be used for at least 600 atomization cycles without significant alteration
of the analytical signal. 相似文献
6.
Nicoleta Petrea Răzvan Petre Andrada Pretorian Constantin Toader Vasile Şomoghi Florentina Neaţu Mihaela Florea Ştefan Neaţu 《Comptes Rendus Chimie》2018,21(3-4):339-345
The catalytic methanolysis of the chemical warfare nerve agents soman, sarin, and VX was investigated by using Cu or Zn complexes. Although VX withstood decontamination, the decomposition yield being around 96%, the soman and sarin deposited on different surfaces were almost fully destroyed under ambient conditions. The catalytic tests performed on a wide range of contaminated surfaces confirm the activity of the investigated catalytic systems, these complexes being suitable, from an economical point of view, for use in the formulation of a possible decomposition kit with military or civilian applicability. 相似文献
7.
Bittencourt MF Dong KE Caetano AL Viel TA Andrada e Silva MA Buck HS 《The Journal of the Acoustical Society of America》2010,128(5):2949-2954
Unlike humans, who communicate in frequency bands between 250 Hz and 6 kHz, rats can communicate in frequencies above 18 kHz. Their vocalization types depend on the context and are normally associated to subjective or emotional states. It was reported significant vocal changes due to administration of replacement testosterone in a trained tenor singer with hypogonadism. Speech-Language Pathology clinical practices are being sought by singers who sporadically use anabolic steroids associated with physical exercise. They report difficulties in reaching and keeping high notes, "breakage" in the passage of musical notes and post singing vocal fatigue. Those abnormalities could be raised by the association of anabolic steroids and physical exercise. Thus, in order to verify if this association could promote vocal changes, maximum, minimum and fundamental frequencies and call duration in rats treated with anabolic steroids and physically trained (10 weeks duration) were evaluated. The vocalizations were obtained by handling the animals. At the end of that period, rats treated and trained showed significant decrease in call duration, but not in other parameters. The decrease in call duration could be associated to functional alterations in the vocal folds of treated and trained animals due to a synergism between anabolic steroids and physical training. 相似文献
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Application of linear regression analysis for iron and copper removal process using natural zeolites
Mihaela-Ligia Ungure?an Andrada M?ic?neanu Francisc-Vasile Dulf Eva-Henrietta Dulf Delia Maria Gligor 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1293-1297
Natural zeolites (zeolitic volcanic tuffs) cropped out from three regions of Transilvania, Vultureni (V), Pagli?a (P) and M?cica? (M), were evaluated in the process of iron (V, P, M) and copper (M) removal from wastewaters. Iron and copper removal process was studied using a fixed bed column, when equilibrium and kinetic data were acquired. Four isotherms, Langmuir, Freundlich, Langmuir?CFreundlich and Redlich?CPeterson, were used to fit the experimental data obtained for each natural zeolite sample. Parameters of the adsorption isotherms were estimated from the experimental equilibrium data using MATLAB. Using these data the best fit with one of the chosen isotherm can be found. Isotherm constants were determined by linear regression analysis of the experimental data. We concluded that the mathematical model based on Freundlich isotherm is the most appropriate to describe the iron and copper exchange on our natural zeolite samples. 相似文献