Synthesis and characterisation of double-layered octahedral coordination polymers built up from divalent metal ions, mixed carboxylate anions, and ethyl carbazate ligands

Supplementary data related to this article can be found at https://doi.org/10.1016/j.molstruc.2018.12.076.Peer reviewedPostprin

Tris(ethyl carbazate-κ2 N,O)nickel(II) dinitrate

The asymmetric unit of the title compound, [Ni(C3H8N2O2)3](NO3)2, contains two independent cations, each built up around a fac-NiN3O3 octa­hedron, and four nitrate anions. Numerous cation-to-anion N—H⋯O hydrogen bonds, some of which are bifurcated, help to establish the packing

Development of Hankel-SVD hybrid technique for multiple noise removal from PD signature

Detection and measurement of partial discharge (PD) phenomena combined with the separation and identification of PD sources is the way to achieve effective insulation integrity assessment. However, during measurement, PD signals are coupled with interferences (discrete spectral, pulsive, and white noises). Recovering PD signals from such interferences would improve PD source separation (thus identification), but still remains a challenging task. Several denoising methods have been proposed to suppress interferences. However, using a universal method to achieve interference removal is probably impossible, as the characteristics of the interferences are distinct. This study proposes a novel low-rank H-Matrix-based singular value decomposition (SVD) filter (H-SVD) that removes different types of interferences. Denoising is done by projecting the measured pulse in a lower dimensional signal space. To assess the effectiveness of the proposed method, H-SVD filter is first applied to simulated PD data and later on real-time PD data with the introduction of three different types of synthetic noises. The results of the evaluation metrics confirm that H-SVD has significant performance improvements compared to existing state-of-the-art PD denoising methods

Partial Discharge Random Noise removal using Hankel Matrix based Fast Singular Value Decomposition

The most effective method for insulation assessment in electrical power apparatus is Partial Discharge (PD) detection. During measurements the interference from background environment hampers the PD signal and reduces its measurement accuracy. This paper discuss on the implementation of a Hankel matrix based Fast Singular Value Decomposition (H-FSVD) technique for removing noise from the PD signals. The data is first represented into Hankel Matrix (HM) structure, with appropriate sampling then using Lanczo process the Hankel matrix size is reduced and through Singular Spectral Analysis thresholds are fixed for noise detection and removal. This algorithm has been examined on simulated as well as PD signals measured on two different laboratory environments from transformers with real and simulated noise.The experiment is part of a series of experiments to detect PD patterns related to realistic transformer defects. The denoising performance of H-FSVD is compared with the wavelet based denoising methods, Empirical Mode Decomposition method and normal SVD. Numerical results show that H-FSVD efficiently removes the noise with less computation time, even for large size data

Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes of 2-nitrobenzoic acid with methyl carbazate as ancillary ligand. Crystal structure of the copper(II) complex

Divalent metal complexes of general formula M(2-nb)(2)(mc)(2)].2(2-nbH), where M = Co(II), Ni(II), Cu(II) or Zn(II), 2-nbH = 2-nitrobenzoic acid and mc = methyl carbazate (NH2NHCOOCH3), have been prepared and characterized by physicochemical and spectroscopic methods. Single-crystal X-ray study of the Cu(II) complex revealed that the molecule is centrosymmetric, with two N,O-chelating mc ligands in equatorial positions and a pair of monodentate 2-nb anions in the axial positions. The lattice 2-nbH molecules help to establish the packing of monomers through hydrogen-bonding interactions. Thermal stability and reactivity of the complexes were studied by TG-DTA. Emission studies show that these complexes are fluorescent

Syntheses and coordination isomerism of heteroleptic divalent-metal (M = Co, Zn) carbazate complexes

<div><p>Three heteroleptic divalent-metal alkyl-carbazate-thiocyanate complexes, [M(NCS)₂(NH₂NHCOOR)₂] [M = Co and R = CH₂CH₃ (<b>1</b>); M = Co and R = CH₃ (<b>2</b>); M = Zn and R = CH₃ (<b>3</b>)], have been prepared and characterized, and their crystal structures determined. In <b>1</b>, Co(II) adopts a fairly regular centrosymmetric <i>trans</i>-CoO₂N₄ octahedral geometry arising from its coordination by two N,O-bidentate ethylcarbazate ligands and two <i>trans</i> N-bonded thiocyanates. In isostructural <b>2</b> and <b>3</b>, the metals adopt distorted <i>cis</i>-MO₂N₄ octahedral geometries arising from two N,O-bidentate methylcarbazate ligands with <i>cis</i> N-bonded thiocyanates. The crystal structures feature N–H⋯O and N–H⋯S interactions. Thermal analysis data show that these compounds begin to decompose at temperatures between 130 and 160 °C. Crystal data: <b>1</b>, CoC₈H₁₆N₆O₄S₂, <i>M</i>_r = 383.32, <i>P2</i>_<i>1</i><i>/n</i> (No. 14), <i>a</i> = 5.2599(3) Å, <i>b</i> = 7.4209(4) Å, <i>c</i> = 20.1948(12) Å, <i>β</i> = 94.070(1)°, <i>V</i> = 786.28(8) ų, <i>Z</i> = 2, <i>R</i>(<i>F</i>) = 0.028, <i>wR</i>(<i>F</i>²) = 0.073; <b>2</b>, CoC₆H₁₂N₆O₄S₂, <i>M</i>_r = 355.27, <i>P2</i>_<i>1</i><i>/n</i> (No. 14), <i>a</i> = 7.8663(3) Å, <i>b</i> = 10.5804(3) Å, <i>c</i> = 17.6313(5) Å, <i>β</i> = 102.019(10)°, <i>V</i> = 1435.26(8) ų, <i>Z</i> = 4, <i>R</i>(<i>F</i>) = 0.036, <i>wR</i>(<i>F</i>²) = 0.097; <b>3</b>, ZnC₆H₁₂N₆O₄S₂, <i>M</i>_r = 361.71, <i>P2</i>_<i>1</i><i>/n</i> (No. 14), <i>a</i> = 7.8883(2) Å, <i>b</i> = 10.5756(3) Å, <i>c</i> = 17.5827(5) Å, <i>β</i> = 101.676(1)°, <i>V</i> = 1436.46(7) ų, <i>Z</i> = 4, <i>R</i>(<i>F</i>) = 0.031, <i>wR</i>(<i>F</i>²) = 0.084.</p></div

A family of double-layered coordination polymers containing Cd²⁺, N,O-chelating ligands, and bridging SCN⁻ and Cl⁻

<div><p>The syntheses, structures, and characterization (IR, TGA/DTA) of a family of layered coordination polymers containing Cd²⁺, bridging anions (SCN⁻ and Cl⁻), and chelating C₂H₆N₂O₂ methyl carbazate (mc) and C₃H₈N₂O₂ ethyl carbazate (ec) ligands are described, viz: Cd(SCN)₂(C₂H₆N₂O₂), Cd(SCN)Cl(C₂H₆N₂O₂), Cd(SCN)₂(C₃H₈N₂O₂), and Cd(SCN)Cl(C₃H₈N₂O₂). Single-crystal structures show them to contain distorted CdN₃OS₂ (for the thiocyanate) and CdN₂OCl₂S (for the thiocyanate/chloride) octahedra, in which the mc and ec ligands adopt an N,O-bidentate coordination mode, and the four anions bridge adjacent metal ions, which leads to polymeric sheets built up from double-octahedral layers propagating in the (1 0 0) plane. The topological linkage of the metal ions, which is the same in each structure, can be described as a distorted hexagonal grid. The crystal structures are completed by weak N–H⋯O, N–H⋯N, N–H⋯Cl, and N–H⋯S hydrogen bonds, which all occur within the (1 0 0) polyhedral layers.</p></div