Sulfate as a ligand in ruthenium(II) and (III) ammines

2001 ◽  
Vol 79 (5-6) ◽  
pp. 679-687 ◽  
Author(s):  
Hildo Antonio dos Santos Silva ◽  
Bruce R McGarvey ◽  
Regina Helena de Almeida Santos ◽  
Mauro Bertotti ◽  
Vânia Mori ◽  
...  
Keyword(s):  
Crystal Structure Data ◽  
Specific Rate ◽  
Heterocyclic Ligands ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Specific Rate Constant ◽  
In Trans ◽  
Intense Absorption ◽  
Electron Paramagnetic ◽  
Metal Charge Transfer

The trans-[RuSO4(NH3)4(L)]Cl complexes, (L = nicotinamide (nia), L-histidine (L-hist), 4-picoline (4-pic), 4-chloropyridine (4-Clpy), isonicotinamide (isn), pyrazine (pyz), 4-aminopyridine (4-NH2py), 4-cyanopyridine (4-CNpy), pyridine (py), imidazole (Him), and water (H2O)), were characterized by elemental analysis cyclic voltammetry, UV-vis, IR, and electron paramagnetic resonance spectroscopies. From the four ν (SO42–) observed only ν3 and ν4 split in two bands each for the sulfate unidentate coordination. The values of Δ/ξ parameters, extracted from g values, allow us to write the following order of increasing π-donation ability: pyz < (py, 4-CNpy, 4-Clpy. 4-pic, isn, nia) < Him < L-hist < 4-NH2py. The intense absorption in the 317-347 nm (ε ~ 2.3-5.6 × 103 M-1 cm-1) region was tentatively assigned to sulfate-to-metal charge transfer (LMCT) and the absorption in the range of 230-270 nm (ε ~ 2 - 6 × 103 M-1 cm-1) assigned to an internal (IL) π-π* transition in the heterocyclic ligands. The rate for the sulfate aquation in trans-[RuSO4(NH3)4L]0 complexes was evaluated through chronopotentiometric measurements and are in the 2.6 s-1 (chloropyridine) to 20 s-1 (pyrazine) range. The SO42– is aquated in trans-[RuIIISO4(NH3)4(4-pic)]Cl at the specific rate constant of (1.4 ± 0.4) × 10-5 s-1, which is very much slower than in trans-[RuIISO4(NH3)4(4-pic)] (5.4 s-1). The X-ray crystal structure data show that the Ru-Cl (2.3444(9) Å) and Ru-NH3 (2.100(2) Å) mean distances in trans-[RuCl(NH3)4(4-pic)]Cl2·H2O are similar to the ones observed in other tetraammineruthenium(III) complexes.Key words: ruthenium, sulfate, ammines.

scholarly journals Electrospun Nanosystems Based on PHBV and ZnO for Ecological Food Packaging

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2123
Author(s):  
Maria Râpă ◽  
Maria Stefan ◽  
Paula Popa ◽  
Dana Toloman ◽  
Cristian Leostean ◽  
...  
Keyword(s):  
Food Packaging ◽  
Spin Trapping ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
Hno3 Solution ◽  
X Ray ◽  
Trapping Method ◽  
Ft Ir ◽  
Doped Zno ◽  
Electron Paramagnetic

The electrospun nanosystems containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and 1 wt% Fe doped ZnO nanoparticles (NPs) (with the content of dopant in the range of 0–1 wt% Fe) deposited onto polylactic acid (PLA) film were prepared for food packaging application. They were investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), antimicrobial analysis, and X-ray photoelectron spectrometry (XPS) techniques. Migration studies conducted in acetic acid 3% (wt/wt) and ethanol 10% (v/v) food simulants as well as by the use of treated ashes with 3% HNO3 solution reveal that the migration of Zn and Fe falls into the specific limits imposed by the legislation in force. Results indicated that the PLA/PHBV/ZnO:Fex electrospun nanosystems exhibit excellent antibacterial activity against the Pseudomonas aeruginosa (ATCC-27853) due to the generation of a larger amount of perhydroxyl (˙OOH) radicals as assessed using electron paramagnetic resonance (EPR) spectroscopy coupled with a spin trapping method.

Jellyfish-like few-layer graphene nanoflakes: high paramagnetic response alongside increased interlayer interaction

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander Ulyanov ◽  
Dmitrii Stolbov ◽  
Serguei Savilov
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Sensitivity ◽  
Paramagnetic Centers ◽  
Interlayer Interaction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Graphene Nanoflakes ◽  
Few Layer Graphene ◽  
Electron Paramagnetic ◽  
Hydrocarbon Pyrolysis

Abstract Jellyfish-like graphene nanoflakes (GNF), prepared by hydrocarbon pyrolysis, are studied with electron paramagnetic resonance (EPR) method. The results are supported by X-ray photoelectron spectroscopy (XPS) data. Oxidized (GNFox) and N-doped oxidized (N-GNFox) flakes exhibit an extremely high EPR response associated with a large interlayer interaction which is caused by the structure of nanoflakes and layer edges reached by oxygen. The GNFox and N-GNFox provide the localized and mobile paramagnetic centers which are silent in the pristine (GNF p ) and N-doped (N-GNF) samples. The change in the relative intensity of the line corresponding to delocalized electrons is parallel with the number of radicals in the quaternary N-group. The environment of localized and mobile electrons is different. The results can be important in GNF synthesis and for explanation of their features in applications, especially, in devices with high sensitivity to weak electromagnetic field.

scholarly journals An Isolable Mononuclear Palladium(I) Amido Complex

2021 ◽  
Author(s):  
jian Liu ◽  
Melissa Bollmeyer ◽  
Yujeong Kim ◽  
Dengmengfei Xiao ◽  
Samantha N. Macmillan ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Bond Cleavage ◽  
Primary Amines ◽  
Dispersion Force ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
X Ray Crystallography ◽  
Pauli Repulsion ◽  
Catalyzed Reactions ◽  
Electron Paramagnetic

Mononuclear Pd(I) species are putative intermediates in Pd-catalyzed reactions, but our knowledge about them is limited due to difficulties in accessing them. Herein, we report the isolation of a Pd(I) amido complex, [(BINAP)Pd(NHArTrip )] (BINAP = 2,2′- bis(diphenylphosphino)-1,1′-binaphthalene, ArTrip = 2,6-bis(2’,4’,6’-triisopropylphenyl)phenyl), from the reaction of (BINAP)PdCl2 with LiNHArTrip. This Pd(I) amido species has been characterized by X-ray crystallography, electron paramagnetic resonance, and multi-edge Pd Xray absorption spectroscopy. Theoretical study revealed that, while the 3-electron-2-center π interaction between Pd and N in the Pd(I) complex imposes severe Pauli repulsion in its Pd–N bond, pronounced attractive inter-ligand dispersion force aids its stabilization. In accord with its electronic features, reactions of homolytic Pd–N bond cleavage and deprotonation of primary amines are observed on the Pd(I) amido complex.

Fabrication, characterization and magnetic properties of Na-doped ZnO nanorods

2016 ◽  
Vol 09 (03) ◽  
pp. 1650039 ◽  
Author(s):  
Jingyuan Piao ◽  
Li-Ting Tseng ◽  
Kiyonori Suzuki ◽  
Jiabao Yi
Keyword(s):  
Magnetic Measurements ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Shallow Donors ◽  
Na Doping ◽  
Transmission Electron ◽  
Doped Zno ◽  
Electron Paramagnetic

Na-doped ZnO nanorods have been fabricated through a hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses indicate that the d spacing of ZnO increases with increasing doping concentration, suggesting the effective incorporation of dopant Na in the samples. Electron paramagnetic resonance (EPR) measurements indicate that there are shallow donors in pure ZnO samples and the shallow donors are strongly prohibited by Na doping. In addition, the resonance at g = 2.005 suggests the formation of Zn vacancies. Magnetic measurements indicate that pure ZnO is paramagnetic and Na doping leads to ferromagnetism at room temperature. Moreover, 0.5% Na-doped ZnO nanorods exhibits the largest saturation magnetization.

Sequestered carbon on clay mineral probed by electron paramagnetic resonance and X-ray photoelectron spectroscopy

2006 ◽  
Vol 295 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Kátia Cylene Lombardi ◽  
Antonio Salvio Mangrich ◽  
Fernando Wypych ◽  
Ubirajara Pereira Rodrigues-Filho ◽  
José L. Guimarães ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Clay Mineral ◽  
Photoelectron Spectroscopy ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Electron Paramagnetic

scholarly journals Influence of the Substituted Ethylenediamine Ligand on the Structure and Properties of [Cu(diamine)2Zn(NCS)4]∙Solv. Compounds

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 637
Author(s):  
Natalia Tereba ◽  
Tadeusz M. Muzioł ◽  
Robert Podgajny ◽  
Grzegorz Wrzeszcz
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Interaction ◽  
Structural Features ◽  
Molecular Formula ◽  
Structure And Properties ◽  
Magnetic Studies ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Ethylenediamine Ligand ◽  
Electron Paramagnetic

In this paper, three new heterometallic compounds were described and compared with the molecular formula [Cu(pn)2Zn(NCS)4] (1), [Cu(N,N-Me2-en)2Zn(NCS)4] (2), [Cu(N-Me-en)2Zn(NCS)4]∙½H2O (3) where pn = 1,2−diaminopropane, N,N-Me2-en = N,N‒dimethylethylenediamine and N-Me-en = N-methylethylenediamine, respectively. The compounds mentioned above were characterized by elemental analysis, infrared (IR), electronic, electron paramagnetic resonance (EPR) spectra, and magnetic studies. Crystal structures for 1 and 2 were determined by X-ray analysis. Copper(II) in these complexes adopts 4 + 2 coordination with two elongated (in 2 very long and considered as semi-coordination) Cu-S bonds. The Cu-N and Cu-S bond lengths depend on substituent position affecting steric hindrance and hence a topology of the chain. Both chains form different zigzag patterns characterized by one or two Cu-Zn distance values. Weak magnetic interaction is observed, ferromagnetic in the case of 1 and antiferromagnetic in the case of 2, due to diversity of the above structural features.

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