Search results for "Thermal"
showing 10 items of 3576 documents
Exploring the Role of Intramolecular Interactions in the Suppression of Quantum Tunneling of the Magnetization in a 3d-4f Single-Molecule Magnet.
2021
Hydroxide-bridged FeIII4LnIII2 clusters having the general formula [Fe4Ln2(μ3-OH)2(mdea)6(SCN)2(NO3)2(H2O)2]·4H2O·2MeCN {Ln = Y (1), Dy (2), mdea = N-methyldiethanolamine} were synthesized and magnetically characterized. The thermal relaxation of the magnetization for 2 and the diluted FeIII4DyIIIYIII complex 3 (with and without applied field) has been analyzed. The diluted sample shows a dominant QTM at low temperatures that can be removed with a 0.15 T dc field. Both 2 and 3 show moderately high Ueff barriers and exhibit hysteresis loops until 5 K.
A systematic study of the optical properties of mononuclear hybrid organo-inorganic lanthanoid complexes
2020
A series of hybrid organo-inorganic mononuclear lanthanoid complexes, [n-NBu4]3[LnH(PW11O39)(phen)2]·H2O, denoted as LM4-1-Ln (Ln = DyIII, TbIII, EuIII, NdIII, ErIII, HoIII and GdIII), were synthesized via hydrothermal synthesis and were structurally characterized by X-ray diffraction. The optical properties of all complexes have been investigated in the solid state. The temperature-dependent emission spectra of LM4-1-Dy, LM4-1-Tb and LM4-1-Eu complexes show intense lanthanoid emissions in the visible region, while LM4-1-Nd shows near-infrared (NIR) luminescence. The EuIII complex shows typical strong red emissions from the 5D0 → 7F0,1,2,3,4 transitions, with the CIE colour coordinates (0.6…
From nitrides to carbides: topotactic synthesis of the η-carbides Fe3Mo3C and Co3Mo3C
2004
The molybdenum bimetallic interstitial carbides Fe(3)Mo(3)C and Co(3)Mo(3)C have been synthesized by temperature-programmed reaction (TPR) between the molybdenum bimetallic interstitial nitrides Fe(3)Mo(3)N and Co(3)Mo(3)N and a flowing mixture of CH(4) and H(2) diluted in Ar. These compounds have been characterized by X-ray diffraction, laser Raman spectroscopy, elemental analysis, energy dispersive analysis of X rays, thermal analysis (in air) and scanning electron microscopy (field emission). Their structures have been refined from X-ray powder diffraction data. These carbides crystallize in the cubic system, space group Fd3m[a= 11.11376(6) and 11.0697(3)[Angstrom] for Fe and Co compound…
The Effect of Pressure on the Cooperative Spin Transition in the 2D Coordination Polymer {Fe(phpy) 2 [Ni(CN) 4 ]}
2013
The effect of pressure on the spin-transition properties of the 2D coordination polymer {Fe(phpy)2[Ni(CN)4]} is reported. The study has been carried out by means of variable-temperature (10–310 K) magnetic susceptibility measurements at applied pressures of 105 Pa to 1.0 GPa and spectroscopic studies in the visible region at room temperature (105 Pa–3.0 GPa). As the pressure is increased, the characteristic temperature of the spin transition is displaced to higher temperatures and the thermal hysteresis loop disappears. A cooperative first-order spin transition characterized by a piezo-hysteresis loop about 0.3 GPa wide was observed at 293 K.
Hydrothermal Synthesis, Crystal Structure, and Magnetism of Na 2 [Ir(OH) 6 ] and its Dehydration to Na 2 IrO 3
2021
Snapshots of the Formation of NaTi3O6(OH)·2H2O Nanowires: A Time-Resolved XRD/HRTEM Study
2013
Layered titanates are important intermediates during the formation of TiO2-related nanostructures in hot concentrated base solution. Microwave-assisted hydrothermal techniques allow a time-resolved ex-situ analysis of the reaction in one-minute intervals by rapid heating and quenching followed by separation and structure analysis of the intermediates. By a combination of powder X-ray diffraction, high resolution electron microscopy (HRTEM), and selected area electron diffraction (SAED) the individual stages of the reaction could be identified. Sodium titanate nanosheets are formed within several minutes by digesting the crystalline TiO2-P25 precursor in NaOH. These nanosheets with a low sod…
Kinetik und Radikalausbeute beim Zerfall tertiärer Hyponitrite
1971
Der thermische Zerfall von Dicumylhyponitrit (1a) ist eine Reaktion erster Ordnung mit einer Aktivierungsenthalpie von 27.3 keal/Mol und einer Aktivierungsentropie von 8.5 cal/Mol·Grad in Isooctan. Die Radikalausbeute fur 1a betragt 84%, fur Di-tert.-butylhyponitrit 92%. Die Zerfallskonstanten substituierter Dicumylhyponitrite gehorchen bei Verwendung der σ+-Werte der Hammett-Beziehung mit σ=+ +0.34. Kinetic and Radical Efficiency for the Decomposition of Tertiary Hyponitrites The thermal decomposition of dicumylhyponitrite (1a) is a first order reaction with an activation enthalpy of 27.3 kcal/mole and an activation entropy of 8.5 e. u. in isooctane. The efficiency of radical formation is …
Thermal, pressure and light switchable spin-crossover materials
2005
This article reviews the most relevant chemical and structural aspects that influence the spin-crossover phenomenon (SCO). Special attention is focussed on the recent development of SCO coordination polymers. The different approaches currently being explored in order to achieve multifunctionality in SCO materials are discussed.
Acid-Promoted Rearrangement of the Metalated Thienyl Rings in Dirhodium(II) Complexes with Thienyl Phosphines as Ligands
2006
Several mono- and bis-cyclometalated compounds have been prepared and characterized from the thermal reaction of dirhodium(II) tetraacetate and tris(2-thienyl)phosphine, P(2-C4H3S)3 (1), in toluene/acetic acid mixtures. In refluxing acetic acid, the mono-cyclometalated compound Rh2(O2CCH3)3[(2-C4H2S)P(2-C4H3S)2] (CH3CO2H)2 (2A) isomerizes to Rh2(O2CCH3)3[(3-C4H2S)P(2-C4H3S)2](CH3CO2H)2 (2B), which results from the selective rearrangement of the metalated ring from a 2-thienyl to a 3-thienyl structure. In the same conditions, the bis-cyclometalated compounds of formula Rh2(O2CCH3)2[(2-C4H2S)P(2-C4H3S)2]2(CH3CO2H)2 and with head-to-tail (3AA) or head-to-head (4AA) configuration of the phosphi…
Stable Methylene- and Oxo-Bridged Monocyclopentadienyl Titanium Compounds. Molecular Structure of {Ti[μ-(η5-C5Me4SiMe2-O)]Me}2(μ-CH2)
2004
Thermolysis of {Ti[μ-(η5-C5Me4SiMe2-O)]Me2}2 affords the methylene-bridged titanium compound {Ti[μ-(η5-C5Me4SiMe2-O)]Me}2(μ-CH2), concurrent with the evolution of methane, the first example of a fu...