Search results for "Molecular magnet"
showing 10 items of 35 documents
Dynamic Magnetic and Optical Insight into a High Performance Pentagonal Bipyramidal Dy(III) Single-Ion Magnet
2017
The pentagonal bipyramidal single-ion magnets (SIMs) are among the most attractive prototypes of high-performance single-molecule magnets (SMMs). Here, a fluorescence-active phosphine oxide ligand CyPh2PO (=cyclohexyl(diphenyl)phosphine oxide) was introduced into [Dy(CyPh2PO)2(H2O)5]Br3⋅2 (CyPh2PO)⋅EtOH⋅3 H2O, and combined dynamic magnetic measurement, optical characterization, ab initio calculation, and magneto-optical correlation of this high-performance pseudo-D5h DyIII SIM with large Ueff (508(2) K) and high magnetic hysteresis temperature (19 K) were performed. This work provides a deeper insight into the rational design of promising molecular magnets.
Revisiting the thiosemicarbazonecopper(II) reaction with glutathione. Activity against colorectal carcinoma cell lines.
2018
Thiosemicarbazones (TSCs), and their copper derivatives, have been extensively studied mainly due to the potential applications as antitumor compounds. A part of the biological activity of the TSC-CuII complexes rests on their reactivity against cell reductants, as glutathione (GSH). The present paper describes the structure of the [Cu(PTSC)(ONO2)]n compound (1) (HPTSC =pyridine-2-carbaldehyde thiosemicarbazone) and its spectroscopic and magnetic properties. ESI studies performed on the reaction of GSH with 1 and the analogous [{Cu (PTSC*)(ONO2)}2] derivative (2, HPTSC* =pyridine-2-carbaldehyde 4N-methylthiosemicarbazone) show the absence of peaks related with TSC-Cu-GSH species. However GS…
Synthesis of novel polypyridylcarbonylpyridines from triazolopyridines. Building blocks in supramolecular chemistry
2009
The synthesis from triazolopyridines 1, of novel triazolopyridylcarbonylpyridylcarbonyltriazolopyridines (TPyCOPyCOTPy) (tpcpctp) 7, and polypyridylcarbonylpyridines (pPyCOPy) (ppcp) 14, building blocks in supramolecular chemistry, is described. These compounds are interesting polynitrogenated ligands as potential molecular sensors, new magnetic materials, single molecular magnets, or in the emerging science of nanomaterials. Abarca Gonzalez, Belen, Belen.Abarca@uv.es ; Ballesteros Campos, Rafael, Rafael.Ballesteros@uv.es ; Chadlaoui, Mimoun, michad@alumni.uv.es
A step further in the comprehension of the magnetic coupling in gadolinium(III)-based carboxylate complexes
2013
Three new gadolinium(III) complexes of formula [Gd4(bta) 3(H2O)16]n·12nH2O (1), [Gd4(bta)3(H2O)12] n·18nH2O (2) and [Gd2(H 2bta)(bta)(H2O)2]n·4nH 2O (3) (H4bta = 1,2,4,5-benzenetetracarboxylic acid) have been synthesized and their structures determined by X-ray diffraction. 1 and 3 are three-dimensional compounds whereas 2 exhibits a two-dimensional structure. The ability of the bta4- to adopt different coordination modes accounts for these high dimensionalities although it precludes a rational structural design. The structures of 1-3 have in common the double oxo-carboxylate bridge between gadolinium(III) ions (μ-O: κ2O,O′) either as a discrete units (1 and 2) or as a chain (3) and one (3)…
Increased conductivity of a hole transport layer due to oxidation by a molecular nanomagnet
2008
Thin film transistors based on polyarylamine poly?N,N?-diphenyl-N,N ?bis?4-hexylphenyl?- ?1,1?biphenyl?-4,4?-diamine ?pTPD? were fabricated using spin coating in order to measure the mobility of pTPD upon oxidation. Partially oxidized pTPD with a molecular magnetic cluster showed an increase in mobility of over two orders of magnitude. A transition in the mobility of pTPD upon doping could also be observed by the presence of a maximum obtained for a given oxidant ratio and subsequent decrease for a higher ratio. Such result agrees well with a previously reported model based on the combined effect of dipolar broadening of the density of states and transport manifold filling. Peer Reviewed
Carbonyl Back-Bonding Influencing the Rate of Quantum Tunnelling in a Dysprosium Metallocene Single-Molecule Magnet.
2019
The isocarbonyl-ligated metallocene coordination polymers [Cp*2M(μ-OC)W(Cp)(CO)(μ-CO)]∞ were synthesized with M = Gd (1, L = THF) and Dy (2, no L). In a zero direct-current field, the dysprosium version 2 was found to be a single-molecule magnet (SMM), with analysis of the dynamic magnetic susceptibility data revealing that the axial metallocene coordination environment leads to a large anisotropy barrier of 557(18) cm–1 and a fast quantum-tunnelling rate of ∼3.7 ms. Theoretical analysis of two truncated versions of 2, [Cp*2Dy{(μ-OC)W(Cp)(CO)2}2]− (2a), and [Cp*2Dy(OC)2]+ (2b), in which the effects of electron correlation outside the 4f orbital space were studied, revealed that tungsten-to-…
Impact of molecule-based magnetic materials: A critical outlook
2009
Abstract A critical outlook of the field of molecular magnetic materials is presented. This article is inspired by an international symposium devoted to the “ Design, Characterization and Modelling of Molecule-Based Magnetic Materials (DCM4-II)” that took place at Strasbourg (France), from May 28th to June 1st, within the E-MRS 2007 Spring Meeting (Symposium R) organized by the European Materials Research Society in collaboration with the European Science Foundation . A series of papers linked to this symposium are published in this issue and in the previous issue (Volume 11, Issue 4) of Solid State Sciences.
Unusual Magnetic Behavior in the Layered Ferromagnet [Ni(C6H14N2)2]3[Fe(CN)6]2·2H2O
2002
The cyano-bridged molecular complex [Ni(C6H14N2)2]3[Fe(CN)6]2·2H2O, with a rectangular 2D structure, displays long-range ferromagnetic ordering at 14 K, and exhibits unusual magnetic properties for this type of material, as confirmed by the appearance of two different peaks in the AC magnetic susceptibility plot, and a high coercive field (2.3 kOe) and remnant magnetization (6.8 μB). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
Coordination isomerism in spin crossover (SCO) materials
2021
International audience; A new series of three spin crossover (SCO) Fe(II) complexes based on a cyanocarbanion and on the neutral quinolin-8-amine (aqin) ligands, [Fe(aqin)2(tcnsme)2] (1), [Fe(aqin)2(tcnset)2] (2), and [Fe(aqin)2(tcnspr)2] (3), has been studied. The three complexes display similar molecular structures consisting of discrete [Fe(aqin)2(tcnsR)2] complexes [R = Me (1), Et (2), and Pr (3)]. Infrared spectroscopy and magnetic studies, performed on the three complexes, revealed the presence of similar SCO behaviors which strongly differ by their transition temperatures [234 K (1) < 266 K (2) < 360 K (3)]. The increase of the transition temperatures when passing from 1 to 3 may be …
Electron-nuclear decoupling at a spin clock transition
2023
The ability to design quantum systems that decouple from environmental noise sources is highly desirable for development of quantum technologies with optimal coherence. The chemical tunability of electronic states in magnetic molecules combined with advanced electron spin resonance techniques provides excellent opportunities to address this problem. Indeed, so-called clock transitions have been shown to protect molecular spin qubits from magnetic noise, giving rise to significantly enhanced coherence. Here we conduct a spectroscopic and computational investigation of this physics, focusing on the role of the nuclear bath. Away from the clock transition, linear coupling to the nuclear degree…