Effect of [Fe(CN)₆]^4– Substitutions on the Spin-Flop Transition of a Layered Nickel Phyllosilicate

Abstract

A 3 to 1 Ni/Si antiferromagnetic layered phyllosilicate, Ni(3)Si(C(3)H(6)NH(3))F(0.65)O(1.9)(OH)(4.45)(CH(3)COO)(1.1)·xH(2)O, was modified with K(4)[Fe(CN)(6)]·3H(2)O. This compound retained its ordering as proved by X-ray diffraction, while infrared spectra revealed the presence of [Fe(CN)(6)](4-) groups and X-ray photoelectron spectroscopy showed that the latter partially substitute the acetate groups. Both the parent and the modified compound are canted antiferromagnets with an anisotropy perpendicular to the layers and show spin-flop transitions. For the parent compound, a single step spin-flop occurs at H = 24 kOe. The modified compound shows increased antiferromagnetic canting and a two-step transition (H(1) = 24 kOe, H(2) = 48 kOe). These results testify to the existence of competing interactions that depend sensitively on the grafted species.

Cationic and anionic azo-dye removal from water by sulfonated graphene oxide nanosheets in Nafion membranes

“…All three originate from 3-amino-1-propanesulfonate and are correlated with C-N and N-H bonds of protonated/ deprotonated amines. 33 Furthermore, a sulphur species is exposed at a high binding energy in the S2p region. The latter is associated with highly oxidized sulphur groups, i.e.…”

Effect of Impregnation with Ammonia vs Silica Support Textural Properties on Ni Nanoparticle Catalysts for Dry Reforming of Methane

“…All of them were characterized by an absorption band assigned to isolated silanols at 3733 cm –1 in the O–H stretching region. However, nickel-based solids prepared in the presence of NH 3 (Figure A, spectra c and d) showed an additional band at 3621 cm –1 that would be due to the vibration of O–H linked with Ni­(II) or of H 2 O encapsulated between the layers of a phyllosilicate structure. , In line with this, such a band did not appear in the spectrum of pure nSiO 2 treated with NH 3 (Figure S3). The 1500–450 cm –1 wavenumber window of the spectra of Ni 5% /nSiO 2 , Ni 5% /nSiO 2 –NH 3 , and nSiO 2 (Figure B) was further analyzed after the dilution of those samples with up to 50% of diamond powder.…”

Revisiting the TCNQF40/1−/2− Catalysis Mechanism for the [Fe(CN)6]3−/4−‐S2O32−/S4O62− Redox Reaction

“…Analysis of UV‐visible spectra of $${{\rm{TCNQF}}_{\rm{4}}^{{\rm{1 - }}} }$$ (at 753 nm) and $${{\rm{[Fe(CN)}}_{\rm{6}} {\rm{]}}^{{\rm{3 - }}} }$$ (at 304 nm) upon completion of the reaction (30 min), revealed that the reaction of 0.60 mM $${{\rm{[Fe(CN)}}_{\rm{6}} {\rm{]}}^{{\rm{3 - }}} }$$ with 0.05 mM $${{\rm{TCNQF}}_{\rm{4}}^{{\rm{2 - }}} }$$ produced 0.05 mM $${{\rm{TCNQF}}_{\rm{4}}^{{\rm{1 - }}} }$$ , with 0.55 mM $${{\rm{[Fe(CN)}}_{\rm{6}} {\rm{]}}^{{\rm{3 - }}} }$$ remaining unreacted (see Table S3), which is exactly as predicted by equation (19). Additionally, the white solid which precipitated during the course of the reaction (see Figure 7(b)) was identified to be $${{\rm{K}}_{\rm{4}} {\rm{[Fe(CN)}}_{\rm{6}} {\rm{]}}}$$ by FTIR (see Figure S10) [17] …”

“…Additionally, the white solid which precipitated during the course of the reaction (see Figure 7(b)) was identified to be K 4 ½FeðCNÞ 6 � by FTIR (see Figure S10). [17]…”