First cobalt complexes with methyl pyruvate semi/thiosemicarbazone - synthesis, physico-chemical and structural characterization

In the reaction of acetone solutions of CoX2∙nH2O (X = Cl, Br) with methyl pyruvate semi/thiosemicarbazone (Hmps, Hmpt) the first Co(II) complexes with these ligands, i.e., [Co(Hmps)(H2O)X2] (X = Cl (1), Br (2)), [Co(Hmpt)2][CoCl4]∙2H2О (3) and [Co(Hmpt)2]Br2∙Me2CO (4) were obtained. Complexes 1 and 2 represent the first examples of metal complexes of Hmps. All the obtained compounds were characterized by elemental analysis, conductometry, magnetic measurements, and IR spectra, and for complexes 2–4, single crystal X-ray diffraction analysis was also performed. The effective magnetic moments were close to the upper limit (5 μB) for complexes 1 and 2, and close to the lower limit (4.4 μB) for complexes 3 and 4, and as such are characteristic for high-spin Co(II) complexes. Structural analysis showed that both ligands coordinate in a neutral form in a tridentate manner, via the ester oxygen, imine nitrogen and the oxygen atom of the ureido (Hmps), or the sulfur atom of the thioureido group (Hmpt). The central metal atoms are situated in a deformed octahedral coordination environment. Complex 2 has cis-Br configuration, while complexes 3 and 4 have mer-configuration

Structural deformation in Hf2Ni observed by TDPAC method

The electric quadrupole interaction in Hf2Ni was measured at 181Ta probe using the time-differential perturbed angular correlation method (TDPAC) in the temperature range 78 to 1314 K. Analysis of the obtained spectra revealed the presence of a single nuclear quadrupole interaction (NQI) and its linear descending dependence with increasing temperature. In the region 1134 to 1314 K, the presence of structural deformation is evident from the coincidence spectra.YUCOMAT 2007 : 9th Annual Conference YUCOMAT 2007 : Programme and the book of abstracts; September 10-14, 2007; Herceg Novi, Montenegr

TDPAC and XRPD measurements of the polycrystalline Hf2Ni phase

The high-resolution time-differential perturbed angular correlation technique (TDPAC) has been used to study the electric field gradient at Ta-181 impurities in the polycrystalline intermetallic compound Hf2Ni in the wide temeperature range 78-1314 K. The single-phase BCT CuAl2 (C16)-type structure of the compound was confirmed by X-ray diffractogram, with lattice constants found to be a = 6.479(3) angstrom and c = 5.271(3) angstrom at room temperature. The coincidence measurements between gamma rays in the cascade were recorded with a time resolution better than 0.75 ns for the 133-482 keV y-y cascade of Ta-181 nuclei. The results of measurements reveal the presence of a single nuclear quadrupole interaction (NQI) WO and its linear dependence with temperature in the range 78-1134 K. In the high temperature region (1134-1314 K) the significant appearance of disordering in the lattice structure of Hf2Ni was revealed, in the vicinity of the melting point of 1473 K. The XRPD measurements in the high temperature range can help in better interpretation and understanding of this complex structural and microdinamic behavior of the Hf2Ni phase.5th International Conference on New Research Trends in Materials Science, Sep, 2007, Sibiu, Romani

The time differential perturbed angular correlation study of the Ni-5 at.% Hf alloy

The time differential perturbed angular correlation technique was used to observe the magnetic dipole and electric quadrupole interactions of (181)Ta probe in the Ni-5 at.% Hf alloy from 78 to 1131 K. The presence of the Larmor precession frequency of (181)Ta in the Ni(Hf) solid solution phase confirms the Ni dominant concentration for the onset of ferromagnetism in the Ni-Hf alloys. A very weak quadrupole interaction originates from imperfections in the HfNi(5) phase formed during melting procedure. The third observed quadrupole interaction corresponds to the Ta probe in the HfO(2) contamination due to internal oxidation of the sample. (C) 2008 Elsevier B.V. All rights reserved.16th International Conference on Solid Compounds of Transition Elements, Jul 26-31, 2008, Dresden, German

TDPAC and XRPD measurements of the polycrystalline Hf2Ni phase

The high-resolution time-differential perturbed angular correlation technique (TDPAC) has been used to study the electric field gradient at Ta-181 impurities in the polycrystalline intermetallic compound Hf2Ni in the wide temeperature range 78-1314 K. The single-phase BCT CuAl2 (C16)-type structure of the compound was confirmed by X-ray diffractogram, with lattice constants found to be a = 6.479(3) angstrom and c = 5.271(3) angstrom at room temperature. The coincidence measurements between gamma rays in the cascade were recorded with a time resolution better than 0.75 ns for the 133-482 keV y-y cascade of Ta-181 nuclei. The results of measurements reveal the presence of a single nuclear quadrupole interaction (NQI) WO and its linear dependence with temperature in the range 78-1134 K. In the high temperature region (1134-1314 K) the significant appearance of disordering in the lattice structure of Hf2Ni was revealed, in the vicinity of the melting point of 1473 K. The XRPD measurements in the high temperature range can help in better interpretation and understanding of this complex structural and microdinamic behavior of the Hf2Ni phase.5th International Conference on New Research Trends in Materials Science, Sep, 2007, Sibiu, Romani

CCDC 900017: Experimental Crystal Structure Determination

Related Article: Svetlana Belošević, Miorad M. Vasojević, Marija S. Jeremić, Auke Meetsma, Zoran D. Matović|2013|J.Coord.Chem.|66|1730|doi:10.1080/00958972.2013.789104,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Magnetic dipole and electric quadrupole interactions of Ta-181 probe in Ni-Hf alloy

The hyperfine interactions of Ta-181 probe in the nickel-2 at.% hafnium alloy have been studied by the perturbed angular correlation method in the temperature range 78-1131K. The magnitude of the magnetic dipole interaction of Hf-181/Ta-181 substituting in ferromagnetic Ni(Hf) solid solution decreases with increasing temperature. As a result of the restricted solid solubility of Hf in Ni, a second phase (HfNi5) in the Ni-Hf sample was detected. Hf-181/Ta-181 which resides in HfNi5 senses weak electric quadrupole interaction. The observed anomalous temperature behavior was ascribed to distortions in the HfNi5 cubic phase. The third measured hyperfine interaction corresponds to the quadrupole interaction of Hf-181/Ta-181 positioned in HfO2 contamination originating from an annealing procedure above 900 K. (C) 2008 Elsevier B.V. All rights reserved

Perturbed angular correlation study of zirconium based C15 laves phases

Laves phases (AB2) are alloys whose metal hydrides have been proposed to improve the energy density of Ni-MH batteries. In case of ZrV2-based battery materials, various amounts of different modifiers, such as Ti and Ni are used to improve their performance. The influence of Ni modifier in ZrV2 C15 Laves phase was investigated at atomic level by the 181TaPerturbed Angular Correlation (PAC) measurements of Zr(V0.33Ni0.67)2, Zr(V0.33Ni0.67)2.4 and Zr27V18Ni55 compounds. The dominant C15-type crystallographic structures were found in all samples by the X-ray diffraction, with the minority presence of other phases, mostly various oxides. The 181Ta-PAC preliminary results showed four different electric quadrupole interactions which give similar values for electric field gradients and non-zero asymmetry parameters in all investigated compounds.HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts; November 13-17, 2023, Nara, Japa