13601-11-1Relevant articles and documents
Swift and efficient nuclear spin conversion of molecular hydrogen confined in Prussian blue analogs
Hori, Akihiro,Matsuda, Ryotaro,Mishima, Akio,Ohba, Masaaki,Ohtani, Ryo,Ohtsubo, Yuta
, p. 149 - 152 (2020)
The ortho-isomer of molecular hydrogen (o-H2) was converted to the para-isomer (p-H2) within 600 s by using Prussian blue analogs, {MII 3[CrIII(CN)6]2} (MCr; M = Mn and Ni), as nuclear-spin conversion catalysts. The swift conversion was confirmed by in-situ Raman micro-spectroscopy under an H2 gas atmosphere (100 kPa) in a low temperature range (2090 K). The o-p ratio observed in MCr deviated from the theoretical value based on the Boltzmann distribution of H2 in a free rotational state to the para-rich proportion, which suggested the promotion of the o-p conversion at higher temperature.
X-ray and neutron-diffraction studies of the crystal structures of the dicesium lithium hexacyanometallates of manganese(III) and chromium(III)
Chadwick,Jones,Wilde,Yerkess
, p. 55 - 66 (1988)
Crystallographic examination of samples of Cs2Li[MIII(CN)6] (MIII=Mn, Cr), prepared by an improved route, establishes the unit cells as very closely approximating to face-centered cubic with lattice constants a=10.64(1) (MIII=Mn) and 10.75(1) A (MIII=Cr). Although a few weak non-face-centered cubic reflections and splittings were detected by powder neutron diffraction, refinement in Fm3m was as good as in primitive cubic or tetragonal space groups. Single-crystal neutron-diffraction refinements in Fm3m yield bond lengths Mn-C=1.980(5) A, Cr-C=2.03(1) A, and C-N=1.188(5) and 1.20(1) A, respectively. At 4.2 K, neutron powder data indicate the presence of further non-face-centered lines for both compounds, with contraction of unit-cell parameters to 10.55(1) and 10.67(1) A, respectively.
Photoinduced magnetism in core/shell prussian blue analogue heterostructures of KjNik[Cr(CN)6] l· n H2O with RbaCob[Fe(CN) 6]c· mH2O
Dumont, Matthieu F.,Knowles, Elisabeth S.,Guiet, Amandine,Pajerowski, Daniel M.,Gomez, Ariel,Kycia, Stefan W.,Meisel, Mark W.,Talham, Daniel R.
, p. 4295 - 4300 (2011)
Core/shell and core/shell/shell particles comprised of the Prussian blue analogues KjNik[Cr(CN)6]l· nH2O (A) and RbaCob[Fe(CN)6] c·mH2O (B) have been prepared for the purpose of studying persistent photoinduced magnetization in the heterostructures. Synthetic procedures have been refined to allow controlled growth of relatively thick (50-100 nm) consecutive layers of the Prussian blue analogues while minimizing the mixing of materials at the interfaces. Through changes in the order in which the two components are added, particles with AB, ABA, BA, and BAB sequences have been prepared. The two Prussian blue analogues were chosen because B is photoswitchable, and A is ferromagnetic with a relatively high magnetic ordering temperature, ～70 K, although it is not known to exhibit photoinduced changes in its magnetic properties. Magnetization measurements on the heterostructured particles performed prior to irradiation show behavior characteristic of the individual components. On the other hand, after irradiation with visible light, the heterostructures undergo persistent photoinduced changes in magnetization associated with both the B and A analogues. The results suggest that structural changes in the photoactive B component distort the normally photoinactive A component, leading to a change in its magnetization.
Photoinduced perturbations of the magnetic superexchange in core@shell Prussian blue analogues
Knowles, Elisabeth S.,Li, Carissa H.,Dumont, Matthieu F.,Peprah, Marcus K.,Andrus, Matthew J.,Talham, Daniel R.,Meisel, Mark W.
, p. 153 - 156 (2013)
Cubic heterostructured core@shell particles of Prussian blue analogues, composed of a shell (～80 nm thick) of ferromagnetic K0.3Ni[Cr(CN) 6]0.8·1.3H2O (A), Tc～70 K, surrounding a bulk (～350 nm) core of photoactive ferrimagnetic Rb 0.4Co[Fe(CN)6]0.8·1.2H2O (B), Tc～20 K, have been studied. Below nominally 70 K, these CoFe@NiCr samples exhibit a persistent photoinduced decrease in low-field magnetization, and these results resemble data from other BA core@shell particles and analogous ABA heterostructured films. This net decrease suggests that the photoinduced lattice expansion in the B layer generates a strain-induced decrease in the magnetization of the NiCr layer, similar to a pressure-induced decrease observed by others in a similar, pure NiCr material and by us in our CoFe@NiCr cubes. Upon further examination, the data also reveal a significant portion of the NiCr shell whose magnetic superexchange, J, is perturbed by the photoinduced strain from the CoFe constituent.
The Synthesis of Potassium Pentacyanohydroxochromate(III)
Sakabe, Yuzuru,Matsumoto, Yoshio
, p. 1253 - 1254 (1981)
The crystals of K3*H2O have been obtained by making Cl2 react with KCN, followed by purification on a Sephadex gel column.
Anisotropic magnetism in Prussian blue analogue films
Pajerowski, Daniel M.,Gardner, Justin E.,Talham, Daniel R.,Meisel, Mark W.
, p. 1320 - 1326 (2011)
A series of Prussian blue analogue (PBA) thin films with thicknesses ranging from 25 nm to 2 μm and with the chemical formula Rb jM1k[M2(CN)6]l·nH 2O have been synthesized using sequential adsorption techniques (where M1 = Co2+, Ni2+, Cu2+, or Zn 2+and M2 = Cr3+ or Fe3+). Since the resulting materials possess the PBA structure, changing the metal ions effectively tunes the magnetization density because SCo = 3/2, SNi = 1, SCu = 1/2, and SZn = 0 on the divalent metal sites and SCr = 3/2 and SFe = 1/2 on the trivalent metal sites. The effect of changing metal ions on the magnetic susceptibility, and specifically the difference between parallel and perpendicular orientations of the films with respect to the applied magnetic field, was investigated with SQUID magnetometry, and all samples, except the ZnFe PBA films, showed magnetic anisotropy. The films were also characterized with infrared spectroscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and scanning electron microscopy.
Interaction of aromatic amino acids with metal hexacyanochromate(III) complexes: A possible role in chemical evolution
Ali, Shah Raj,Kamaluddin
, p. 1541 - 1546 (2006)
Metal cyanogen complexes have been proposed to be efficient prebiotic catalysts. Insoluble metal cyanogen complexes are thought to have concentrated biomonomers from dilute prebiotic soup which facilitated a class of prebiotic reactions. Thus, large biopolymers were able to form during the course of chemical evolution and the origin of life. Based on this hypothesis, the interaction of two naturally occurring α-aromatic amino acids, tryptophan and phenylalanine, with cobalt(II), copper(II), and cadmium(II) hexacyanochromate(III) has been studied, and the interaction was found to be strongest at neutral pH (≈7:0). Cobalt(II) hexacyanochromate(III) adsorbed the largest amount of both amino acids while tryptophan had a stronger affinity than phenylalanine. Infrared spectral studies of the metal hexacyanochromate( III) complexes, amino acids and metal hexacyanochromate(III)-amino acid adducts indicated the involvement of NH2 as well as COO- groups of amino acids and surface metal ions present in the lattice of the metal hexacyanochromate(III) complexes.
The interaction of ribonucleotides with metal hexacyanochromates(III) and the relevance to chemical evolution
Ali, Shah Raj,Kamaluddin
, p. 1681 - 1686 (2004)
The interaction of ribonucleotides, namely 5′-AMP, 5′-GMP, 5′-CMP, and 5′-UMP, with cobalt(II) and cadmium(II) hexacyanochromates(III) has been studied. Maximum adsorption was observed at a neutral pH. Adsorption isotherms were found to be Langmuirian in nature. Values for Xm and KL were calculated. Purine nucleotides showed more adsorption than pyrimidine nucleotides on both the metal hexacyanochromates(III), whereas cobalt(II) hexacyanochromate(III) was found to be a better adsorbent for all of the ribonucleotides studied. Infrared spectral studies of the adsorption adducts suggested that adsorption occurs due to interactions between the phosphate moiety and base residue of the ribonucleotide molecule with outer divalent metal ions present in the lattice of metal hexacyanochromates(III). The results of the present study support the hypothesis that metal cyanogen complexes might play an important role in concentrating and stabilizing the biomonomers on their surfaces through adsorption processes during the course of chemical evolution.
Effect of pressure on the magnetic properties of LiCuFe and LiCuFe@LiNiCr Prussian blue analogues
Peprah, Marcus K.,Li, Carissa H.,Talham, Daniel R.,Meisel, Mark W.
, p. 264 - 267 (2013)
Magnetic studies on the Prussian blue analogues (PBAs) Li xCuy[Fe(CN)6]z·mH 2O (LiCuFe-PBA) and LijNik[Cr(CN) 6]l·nH2O (LiNiCr-PBA), as well as LiCuFe@LiNiCr-PBA core-shell heterostructures, have been conducted under pressures ranging from ambient to ≈1.4 GPa and at temperatures of 2-90 K. The results for the single component CuFe-PBA indicate robust magnetic properties under the range of pressures studied where a Tc = 20 K was observed at all pressures. Our pressure studies of single component NiCr-PBA are consistent with previously published results by other workers below 1.0 GPa. However, at pressures above 1.0 GPa, the decrease in magnetization is accompanied by a decrease in the Tc, an indication of changes in the superexchange value. The results obtained with the single component samples can be mapped onto the observations of the heterostructures.
Anation kinetics of pentacyanoaquachromate(III) by thiocyanate and azide
Riccieri, Pietro,Zinato, Edoardo
, p. 897 - 907 (2007)
The kinetics of the reaction of Cr(CN)5(H2O)2- with NCS- and N3- were studied at pH 5.0 and at pH 6.3-7.0, respectively, as a function of the temperature between 25.0 and 55.0 °C, and at various ionic strengths. Anation occurs in competition with aquation of CN-, with rate constants that exhibit less-than-first-order dependence on the concentration of the entering anions. The results are interpreted in terms of ligand interchange in a context of association of the two reacting anions mediated by the Na+ or Ca2+ counterions. The degree of aggregation depends mainly on the total cationic charge rather than on the ionic strength, and is ca. 2-fold larger for N3- than for NCS-. Within the associated species, N3- is a better entering ligand than NCS- by a factor of 4.5. The Cr(CN)5(NCS)3- and Cr(CN)5(N3)3- complexes were also synthesized, and the rates of aquation of NCS- and N3-were measured at pH 5.0 and between 55.0 and 80.0 °C, over the same range of ionic strengths. The ionic strength enhances the anation rates but has little effect on the aquation rates. The average activation enthalpies of the interchange step are 80 ± 3 and 76 ± 3 kJ mol-1 for entry of NCS- and N3-, respectively. Those of the corresponding aquation reactions are 94 ± 4 and 107 ± 4 kJ mol-1. Within error limits, all ΔH? values are independent of the ionic strength. The results are consistent with an Id mechanism for substitution in Cr(CN)5Xz- complexes.
