Search results for "osso"

Quadrupole splitting of Fe(II) spin crossover compounds study of temperature and pressure dependence and the implication for the interaction mechanism

1989

The temperature and pressure dependence of the quadrupole splitting ΔE Q of the 3/2→1/2 nuclear Mossbauer transition of57Fe in the spin crossover compounds [Fe x Zn1−x (2-pic)3]Cl2⋆EtOH and the deuterated analog [Fe x Zn1−x (2-pic-ND2)3] Cl2⋆EtOD (2-pic=2-picolylamine) have been studied. The change of ΔE Q can be linearly related to the defomation of the lattice as observed by X-ray measurements. The dependence of ΔE Q on temperatureT, pressurep, and the fraction γ of molecules in the electronic high spin state in the pure iron (x=1) compounds is therefore interpreted as a result of the change of the lattice contribution to the electric field gradient (EFG) at the nucleus only. The intrinsi…

Lamb-Mössbauer factor in the spin crossover compound Fe(tpa)(NCS)2

1994

The Lamb-Mossbauer factor in spin crossover compounds has been the subject of controversial discussions in the literature. For several compounds, a significantly larger Lamb-Mossbauer factor for the complex molecules in the low-spin (fls) than in the high-spin (fhs) state has been reported, while for compounds studied in our laboratory such differences could not be observed. We prepared the compound Fe(tpa)(NCS)2, thef factors of which were reported to be very different. We could not prove thef factors of this compound to be different. The implications of a different structural phase of compound prepared by us are discussed.

Mössbauer effect study of the temperature and pressure dependence of the singlet-quintet intersystem crossing dynamics in an iron(II) spin crossover …

1988

The lineshapes of Mossbauer spectra of the iron(II) spin crossover complex [Fe(6-mepy)3 tren] (PF6)2 are affected by the dynamics of the HS⇌LS equilibrium. The lineshapes are reproduced with a stochastic two-state-relaxation-model yielding rate constants similar to those determined for related complexes in solution. Application of an external pressure of 150 MPa increases the relaxation rate.

Light-induced formation of metastable high-spin states in [Fe(mtz)6](CiO4)2

1988

[Fe(mtz)6](CiO4)2 (mtz=1-methyltetrazole) is a spin crossover compound with two different iron(II) lattice sites. Only one of them (lattice site A) shows thermally induced high spin (HS) ⇌ low spin (LS) spin transition. The LIESST effect (Light-Induced Excited Spin State Trapping) can be observed below 50 K. Complex molecules in B-sites remain in HS state at all temperatures. At ∼ 20 K irradiation with red light causes a partial conversion to another HS species, HS(C), with also practically infinite lifetime.

Spin transition in iron complexes induced by heat, pressure, light and nuclear decay

1988

The phenomenon of temperature-dependent spin transition will be introduced and the numerous chemical and physical influences affecting the spin transition characteristics will be discussed. We shall mainly concentrate on the spin crossover system [Fe(2-pic)3]X2·Sol (2-pic=2-aminomethylpyridine; X=Cl, Br; Sol=C2H5OH, CH3OH) and demonstrate how the behaviour of the spin transition5T2g(Oh)⇌1A1g(Oh) is influenced by substituting the metalion, the non-coordinating anions X, the crystal solvent molecules Sol and by isotopic exchange with H/D and14N/15N. It will also be shown that the spin transition is very susceptible to pressure. A quantitative spin state conversion from low spin to high spin c…

Pressure effect on a novel spin transition polymeric chain compound

2000

[Fe(hyptrz)3]A2·H2O (hyptrz = 4-(3′-hydroxypropyl)-1,2,4-triazole and A = 4-chlorobenzenesulfonate) represents a novel iron(II) polymeric chain compound. A discontinuous spin transition has been observed by temperature dependent magnetic susceptibility measurements. The spin transition curves are shifted from 181 K to 324 K as the pressure varies from 1 bar to 5.9 kbar. The shapes of these curves are not strongly modified, and this is interpreted as being due to effective cooperative interactions along the chain. This behaviour under pressure can be extended to the family of iron(II)-1,2,4-triazole polymeric chain spin crossover materials.

Spin Transition Phenomena

2003

Bioavailability of plant sterol-enriched milk-based fruit beverages: In vivo and in vitro studies

2015

Abstract This study for the first time compares the in vivo (response in serum from individuals of an interventional study) and in vitro effects (bioaccessibility determined from simulated gastrointestinal digestion) of two plant sterol (PS)-enriched milk-based fruit beverages (with and without tangerine fruit juice rich in β-cryptoxanthin (β-Cx)) in order to assess their suitability as PS-enriched food matrixes, and the possible interactions between the two bioactive compounds (β-Cx and PS) that might affect their absorption. The randomized, double-blind, crossover study (performed in 36 postmenopausal women) showed the β-sitosterol and campesterol serum concentrations after four weeks of …

Profilin 1 negatively regulates osteoclast migration in postnatal skeletal growth, remodeling, and homeostasis in mice

2019

ABSTRACT Profilin 1 (Pfn1), a regulator of actin polymerization, controls cell movement in a context‐dependent manner. Pfn1 supports the locomotion of most adherent cells by assisting actin‐filament elongation, as has been shown in skeletal progenitor cells in our previous study. However, because Pfn1 has also been known to inhibit migration of certain cells, including T cells, by suppressing branched‐end elongation of actin filaments, we hypothesized that its roles in osteoclasts may be different from that of osteoblasts. By investigating the osteoclasts in culture, we first verified that Pfn1‐knockdown (KD) enhances bone resorption in preosteoclastic RAW264.7 cells, despite having a compa…

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

2017

Novel vanadium complexes bearing [OSSO]-type ligands having two phenolato units linked through the –CH2S(CH2)4SCH2– (1V) or –CH2S(CH2)2SCH2– (2V) bridge are synthesized with good yields by reacting a deprotonated ligand with VCl4. They are then used in ethylene (co)polymerization after activation with EtAlCl2 and Et2AlCl. In the presence of EtAlCl2, both complexes promote ethylene polymerization with very high activities, over 4 × 107 g/(mol h), leading to PEs with high molecular weight and narrow molecular weight distribution. The prepared complexes exhibit lower activity for ethylene/1-octene copolymerization. It is also revealed that the catalyst based on the –CH2S(CH2)4SCH2– bridged com…