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Molecular, Supramolecular Structures Combined with Hirshfeld and DFT Studies of Centrosymmetric M(II)-azido {M=Ni(II), Fe(II) or Zn(II)} Complexes of…
2021
The supramolecular structures of the three metal (II) azido complexes [Fe(4bzpy)4(N3)2]
One-dimensional oxalato-bridged copper(II) complex possessing two structurally different metallic centres
2001
Abstract The crystal structure of the oxalato-bridged copper(II) compound [Cu2(μ-ox)2(ampy)3]n 1 (ox=oxalate dianion, ampy=2-amino-3-methylpyridine) consists of infinite corrugated one-dimensional chains in which two types of copper(II) centres, five- and six-coordinated, are bridged sequentially by asymmetric bis-bidentate oxalato ligands. Magnetic susceptibility measurements show the occurrence of a significant intrachain antiferromagnetic coupling (J=−22.9 cm −1 ) .
Sintering of copper nanopowders under hydrogen: an in situ X-ray diffraction analysis.
2003
Abstract The reduction by hydrogen gas of the cuprite layer on copper nanocrystals and the subsequent sintering of the nano-particles were studied using in-situ X-ray diffraction and dilatometry. Spherical nanocrystals produced by evaporation and condensation have an average size of 35 nm, exhibiting a large surface curvature. Each nanoparticle is coated with a 3.5 nm layer of Cu 2 O, which is rough and disordered, as revealed by high-resolution electron microscopy. Reduction by hydrogen of this curved cuprite layer occurs at 363 K, which is ≈65 K lower than is observed on a layer supported by micrometer-sized or bulk copper with a flat surface. The reduction process and its effect on the s…
A Combined Experimental and Theoretical Study on the Magnetic Properties of a Family of Bis(μ‐phenoxido)dicopper(II) Complexes Bearing ω‐[Bis(2‐hydro…
2009
Five new neutral bis(μ-phenoxido)dicopper(II) complexes, [Cu2(μ-HL1)2]·3EtOH·H2O (1), [Cu2(μ-HL2)2]·1.65H2O (2), [Cu2(μ-HL3)2(μ-H2O)] (3), [Cu2(μ-HL4)2] (4) and [Cu2(μ-HL5)2(μ-H2O)] (5), were prepared from a family of ω-[bis(2-hydroxy-3,5-dimethylbenzyl)amino]alkan-1-ol ligands (H3L1–H3L5 derived from 2-aminoethanol, 3-aminopropanol, 4-aminobutanol, 5-aminopentanol and 6-aminohexanol, respectively) bearing a [O,N,O,O′] donor set. In complexes 3 and 5, there is also a bridging water molecule between the metallic centres. The copper(II) coordination planes of all these complexes form a roof-like structure (the bridging O atoms are located at the top of the roof). The structural differences fo…
Über blei-haltige Heterocyclen
1990
Abstract Crystal structures of alternating six-membered rings [Ph2PbS]3-P21/c and [Ph2SnS]3-P21/n have been determined by X-ray methods. Both heterocycles exhibit a C2-symmetric twisted boat conformation with tetrahedral coordination of the metal atoms [dPbS 2.491 A (dSnS 2.401 A, dPbC 2.19 A (dSnC 2.129 A)]. No additional intermolecular contacts have been found. A ring-segment exchange reaction in solution has been observed by NMR. In the resulting equilibrium new cyclic compounds containing both tin and lead atoms with coupling constants 2J(207PbS119Sn) 226 Hz have been detected. FD-mass spectra indicate formation of dimeric molecular units.
Syntheses and Structural Study of Novel Tetranuclear Bis(phenoxido)‐Bridged Cu II Metal–Organic Macrocycles
2012
Six new tetranuclear copper(II) complexes were prepared exploiting novel ditopic alkylenediamine-N,N,N′,N′-tetraphenolate ligands. The geometrical parameters of the compounds can be varied by introducing different solvents of crystallization into the lattice. The structures of all six complexes were determined from single-crystal X-ray diffraction analyses and the magnetic properties of the complexes were estimated by computational DFT calculations. The relationship between the magnetic exchange coupling constant (J) and the Cu–O–Cu angle (θ) in these bis(phenoxido)-bridged complexes was investigated and a magnetostructural correlation was established between J and the θ angle. All studied …
Hot electron effects in metallic single electron components
1996
Thermalisation of single electron devices is of considerable current interest because of its fundamental and practical consequences. We present experimental evidence of the effect of electrode volume and its shape on thermal equilibration of small metallic islands for single electron tunnelling. Heat transport between the conduction electrons and the lattice in a metal is commonly accepted to obey the ∝Te5-T0/5 law at low electron and lattice temperatures,Te andT0, respectively. We have investigated the power law and found that it obeys the ∝T5 law only for the smallest islands, and in the majority of the cases considered, it rather follows a law ∝Tp, wherep<5. The thermal coupling can be i…
Single and Twofold Metal- and Reagent-Free Anodic C-C Cross-Coupling of Phenols with Thiophenes.
2017
The first electrochemical dehydrogenative C-C cross-coupling of thiophenes with phenols has been realized. This sustainable and very simple to perform anodic coupling reaction enables access to two classes of compounds of significant interest. The scope for electrochemical C-H-activating cross-coupling reactions was expanded to sulfur heterocycles. Previously, only various benzoid aromatic systems could be converted, while the application of heterocycles was not successful in the electrochemical C-H-activating cross-coupling reaction. Here, reagent- and metal-free reaction conditions offer a sustainable electrochemical pathway that provides an attractive synthetic method to a broad variety …
Ferromagnetic Coupling through Spin Polarization in a Dinuclear Copper(II) Metallacyclophane.
2001
[DT] Von organischen Radikalen zu Metallkomplexen konnte das bekannte Konzept für Ferroelektrika erfolgreich ausgedehnt werden: Die Abbildung zeigt ein Cyclophan-artiges Molekül mit einem Triplett-Grundzustand, in dem zwei CuII-Zentren von einem doppelten m-Phenylendiamid-Gerüst zusammengehalten werden.
Fatigue Crack Growth for Different Ratios of Bending to Torsion in AlCu4Mg1
2008
The paper contains the fatigue crack growth test results obtained under proportional bending with torsion in AlCu4Mg1 aluminium alloy [1]. Specimens with rectangular cross sections and dimensions: length l = 90 mm, height w = 10 mm and thickness g = 8 mm were tested [2]. Each specimen had an external unilateral notch with depth 2 mm and radius ρ = 0.2 mm. The tests were performed under the stress ratio R = −1. The notches in the specimens were cut with a milling cutter and their surfaces were polished after grinding. The tests were realized on a fatigue test stand MZGS-100 where the ratio of torsion moment to bending moment was \( M_T (t)/M_B (t) = tg\alpha = \sqrt 3 /3,1{\text{ }}and\sqrt …