8 research outputs found
N-[(2H-1,3-benzodioxol-5-yl)methyl]-2-(2,2,2-trichloroacetamido)benzamide
No full textThe structure of N-[(2H-1,3-benzodioxol-5-yl)methyl]-2-(2,2,2-trichloroacetamido)benzamide was verified by using a combination of 1D and 2D NMR techniques. Fully assigned data from 1D NMR (1H, 13C and DEPT 135) and 2D NMR (COSY, HMQC, HMBC) spectra was presented for the compound. The 1H NMR spectrum of the ABX spin system in the benzodioxol moiety was simulated to predict the corresponding nJHH coupling constants. The spectral assignments for the structure were supported by interpretive library search and HOSE predictions
Modified MSIS chamber as a novel gas–liquid separator coupled with the photochemical vapor generation of trace mercury with MP-AES detection
No full textNew hyphenation of continuous flow photochemical vapor generator (PVG) to modified multimode sample introduction system (MSIS) used as gas-liquid separator and microwave plasma atomic emission spectrometry (MP-AES) was proposed for analysis of trace mercury. The widened MSIS bottom inlet contributes to the increase of the Hg0 mass transfer in the gas-liquid separator allowing the mercury determination by MP-AES. After optimizing the PVG reactor conditions and MP-AES instrument parameters a limit of detection (LOD) of 0.25 ppb was obtained for Hg2+. The applicability of the PVG-MSIS-MP-AES method was subsequently demonstrated for trace mercury analysis in two soil CRMs - ERM-CC135a (Contaminated Brickworks soil) and CRM005 (Sewage Amended soil).This study is financed by the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project № BG-RRP-2.004-0001-C01
A Complete 1H and 13C NMR Data Assignment for Three 3-[Substituted methylidene]-1H,3H-naphtho-[1,8-cd]-pyran-1-ones
No full textA combination of 1D and 2D NMR techniques, including HMQC, HSQC, 1H-1H COSY and HMBC, was used to provide completely assigned 1H and 13C NMR data for the structures of three 3-[substituted methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-ones—3-[(4-methoxyphenyl)methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-one, 3-[(4-fluorophenyl)methylidene]-1H,3H-naphtho-[1,8-cd]-pyran-1-one and 3-[(thiophen-3-yl)methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-one. The heteronuclear coupling constants 1–4JCF and 3–4JHF were correspondingly determined. Additionally, IR and Raman spectral data were provided in support of the assigned structures
5′-Oxospiro-(fluorene-9,4′-imidazolidine)-2′-thione
No full textThe structure verification of 5′-oxospiro-(fluorene-9,4′-imidazolidine)-2′-thione by NMR is reported. Toward this aim, 2D NMR techniques including 1H-1H COSY, HMQC, and HMBC experiments were used to assist with the assignment of the 1H and 13C chemical shifts for the corresponding structure. The mutual interpretation of the 1D and 2D NMR spectra ensured a complete and accurate 1H and 13C NMR data assignment for 5′-oxospiro-(fluorene-9,4′-imidazolidine)-2′-thione
Variation after particle-number projection for the Hartree-Fock-Bogoliubov method with the Skyrme energy density functional
No full textVariation after particle-number restoration is incorporated for the first time into the Hartree-Fock-Bogoliubov (HFB) framework employing the Skyrme energy density functional with zero-range pairing. The resulting projected HFB equations can be expressed in terms of the local gauge-angle-dependent densities. Results of projected calculations are compared with those obtained within the Lipkin-Nogami method in the standard version and with the Lipkin-Nogami method followed by exact particle-number projection.Physics, NuclearSCI(E)0ARTICLE1null7
Wear metals determination in lubricating oils by reversed-phase dispersive liquid-liquid microextraction and microwave induced plasma optical emission spectrometry
No full textA periodic study of the engine oil can allow to anticipate possible breakdowns that the vehicle could have. Due to the complexity of the matrix of this type of samples, a sample treatment prior to analysis is necessary. Analytical chemistry is constantly searching for simpler, more sensitive and environmentally friendly methods. The reverse phase dispersive liquid-liquid microextraction fulfills all the characteristics for the analysis in this type of sample by microwave plasma atomic emission spectrometry (MIP OES). In this work, the extractant solvent used for the microextraction procedure is a diluted acid solution (i.e., 3 M HCl), which is a less-hazardous solvent, in comparison with other solvent used in microextraction procedures. Besides, it is perfectly compatible with MIP OES. The main experimental factors affecting the extraction of Cr, Cu, Mn, Mo, and Ni (i.e., amount of sample, extractant type, acid concentration, extractant volume, extractant time, and centrifugation time and speed) are optimized using a multivariate analysis consisting in two steps: a Plackett-Burman design followed by a circumscribed central composite design. Under optimum conditions (i.e., amount of sample: 5.9 g; extractant volume: 60 µL; extractant type: HCl; acid concentration: 3 M; extraction time: 3 min; centrifugation time: 3 min; centrifugation speed: 2000 rpm), the proposed analytical method is validated and employed to analyze different samples (i.e., used and unused engine oils). Two calibration methods have been evaluated since matrix effects have been observed in the used engine oil sample. These effects have been eliminated using standard addition calibration obtaining RSD and recovery values in the range of 4-12 % and 94-106 % respectively, for samples spiked with 1 µg g-1 of Cr, Cu, Mn, Mo and Ni. Finally, the greenness of this method has been assessed by the Eco-Scale metrics.The authors would like to thank the Spanish Ministry of Science and Innovation (PID2021-126155OB-I00), the Regional Government of Valencia (Spain) (CIPROM/2021/062), and University of Alicante (UAIND21-03C) for the financial support. 15% of this study is financed by the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project number BG-RRP-2.004-0001-C01. This article is based upon work from the Sample Preparation Study Group and Network, supported by the Division of Analytical Chemistry of the European Chemical Society. Finally, the authors would also like to thank Agilent Technologies Inc. for the loan of the MIP OES spectrometer and Ingeniatrics for the OneNeb® Series 2 provided. This work is part of the PhD. Degree of C. S
Investigation of the Complexation Activity of 2,4-Dithiouracil with Au(III) and Cu(II) and Biological Activity of the Newly Formed Complexes
No full textThe goal of this study is to synthesize, determine the structure, and examine the antimicrobial properties of novel Cu(II) and Au(III) complexes of 2,4-dithiouracil and its derivatives. These complexes were obtained by mixing aqueous solutions of the corresponding metal salts with the ligand dissolved in DMSO and aqueous NaOH, using a metal-to-ligand ratio of 1:4:2. The structures of the new compounds were analyzed by melting point determination, microwave plasma atomic emission spectrometry (MP-AES) for Cu and Au, inductively coupled plasma optical emission spectrometry (ICP-OES) for S, attenuated total reflection (ATR), solution and solid-state NMR, and Raman spectroscopy. The data for 2,4-dithiouracil obtained from the 1H NMR, 13C NMR, distortionless enhancement by polarization transfer spectrum (DEPT-135), proton–proton homonuclear correlation spectrum (1H-1H COSY), long-range 1H-13C heteronuclear multiple bond correlation experiment (HMBC), and heteronuclear single quantum coherence spectra (HSQC) aided the interpretation of the NMR data for the gold and copper complexes. Furthermore, the antimicrobial effect of the free ligands and their complexes was assessed against Gram-positive and Gram-negative bacteria, as well as yeasts
Deformed coordinate-space Hartree-Fock-Bogoliubov approach to weakly bound nuclei and large deformations
No full textThe coordinate-space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables the self-consistent treatment of mean field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei, which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate two-dimensional lattice Skyrme-HFB solver HFB-AX based on basis (or B)-splines. Compared to previous implementations, ours incorporated a number of improvements aimed at boosting the solver's performance. These include the explicit imposition of axiality and space inversion, use of the modified Broyden method to solve self-consistent equations, and a partial parallelization of the code. HFB-AX has been compared with other HFB codes, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multiresolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, HFB-AX can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB frameworks, both existing and in development.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000262248100014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, NuclearSCI(E)36ARTICLE6null7
