Pressure tunablity in ReX4based SMMs; A magnetostructural study

Since the discovery of Single-Molecule Magnets (SMMs) in 1993 there has been extensive interest in understanding, developing and tuning the nature of magnetic interactions within SMMs with the intention of gaining greater insight into the nature of these interactions.[1] Typically this is done synthetically using variations in ligand geometry and co-ordination environment to vary magnetic behaviour. More recently it has been demonstrated that high hydrostatic pressure are also an effective mechanism for "tuning" properties such as magnetic susceptibility in a variety of SMMs.[2] The number of studies utilising high hydrostatic pressure to investigate molecular magnetism is extremely limited due to their inherent difficulty however we report a new study investigating the pressure tunabilty of Re(IV) based SMMs. 4d and 5d metal ions such as Re are of interest due their enhanced magnetic exchanges relative to their 3d analogues and Re(IV) based complexes are of particular interest. Previous studies into [ReX6]2-(X = Cl, Br and I) anions demonstrate significant antiferromagnetic coupling, not transmitted through chemical interactions but rather through weak Re-X...X interactions in the solid state which may be easily perturbed at high pressure. [3] Therefore we report an investigation into the tunability of magnetic susceptibility in a variety of [ReX4] based compounds using high pressure magnetic susceptibility measurements and correlate the results with structure observations taken from high pressure single crystal X-ray diffraction experiments. The effects of the removal of solvent trapped in the lattice using temperature and vacuum and the corresponding effect on magnetic behaviour and chemical structure are also reported.

Download Full-text

High-Pressure Study of Oxo-bridged Mixed-Valent MnIII/MnIV Dimers High-Pressure Study of Oxo-bridged Mixed-Valent MnIII/MnIV Dimers

Zeitschrift für Naturforschung B ◽

10.1515/znb-2010-0302 ◽

2010 ◽

Vol 65 (3) ◽

pp. 221-230 ◽

Cited By ~ 4

Author(s):

Alessandro Prescimone ◽

Javier Sanchez-Benitez ◽

Konstantin V. Kamenev ◽

John E. Warren ◽

Alistair R. Lennie ◽

...

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

Single Crystal ◽

Magnetic Behaviour ◽

Squid Magnetometry ◽

X Ray Diffraction ◽

Space Group ◽

X Ray ◽

Bond Lengths ◽

High Pressure Study

A combination of high-pressure single crystal X-ray diffraction and high-pressure SQUID magnetometry has been used to study two oxo-bridged mixed-valent MnIII/MnIV dimers. [Mn2O2(bpy)4](ClO4)3·3CH3CN, (1·3CH3CN; bpy = 2,2ʹ-bipyridine) has been compressed to 2.0 GPa whilst [Mn2O2(bpy)4](PF6)3·2CH3CN·1H2O, (2·2CH3CN·1H2O) could be measured crystallographically up to 4.55 GPa. The PF6 salt of [Mn2O2(bpy)4]3+ has never been reported before while 1 has been reported as a hydrate and in a different crystallographic space group. The application of hydrostatic pressure imposes significant distortions and modifications in the structures of both complexes. In particular, in complex 1·3CH3CN the Mn-Mn separation is reduced by the contraction of some of the Mn-O bond lengths, whilst in 2·2CH3CN·1H2O the Mn-O-Mn bridging angles and the Mn-O bond lengths are substantially unchanged. Interestingly 2·2CH3CN·1H2O also shows a constant contraction in nearly all the Mn-N bonds. The magnetic behaviour of the complexes has been measured up to 0.87 GPa for 1·3CH3CN and 0.84 GPa for 2·2CH3CN·1H2O.

Download Full-text

Series of Chloranilate-Bridged Dinuclear Lanthanide Complexes: Kramers Systems Showing Field-Induced Slow Magnetic Relaxation

Magnetochemistry ◽

10.3390/magnetochemistry5020030 ◽

2019 ◽

Vol 5 (2) ◽

pp. 30 ◽

Cited By ~ 3

Author(s):

Ryuta Ishikawa ◽

Shoichi Michiwaki ◽

Takeshi Noda ◽

Keiichi Katoh ◽

Masahiro Yamashita ◽

...

Keyword(s):

Magnetic Susceptibility ◽

Single Molecule ◽

Magnetic Relaxation ◽

Lanthanide Complexes ◽

Relaxation Processes ◽

X Ray Diffraction ◽

Single Molecule Magnets ◽

Magnetic Susceptibility Data ◽

Susceptibility Data ◽

Slow Magnetic Relaxation

A series of chloralilate-bridged dinuclear lanthanide complexes of formula [{LnIII(Tp)2}2(μ-Cl2An)]·2CH2Cl2, where Cl2An2− and Tp− represent the chloranilate and hydrotris (pyrazolyl)borate ligands, respectively, and Ln = Gd (1), Tb (2), Ho (3), Er (4), and Yb (5) was synthesized. All five complexes were characterized by an elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and SQUID measurements. The complexes 1–5 in the series were all isostructural. A comparison of the temperature dependence of the dc magnetic susceptibility data of these complexes revealed clear differences depending on the lanthanide center. Ac magnetic susceptibility measurements revealed that none of the five complexes exhibited a slow magnetic relaxation under a zero applied dc field. On the other hand, the Kramers systems (complexes 4 and 5) clearly displayed a slow magnetic relaxation under applied dc fields, suggesting field-induced single-molecule magnets that occur through Orbach and Raman relaxation processes.

Download Full-text

Cu(ii)–Dy(iii) and Co(iii)–Dy(iii) based single molecule magnets with multiple slow magnetic relaxation processes in the Cu(ii)–Dy(iii) complex

Dalton Transactions ◽

10.1039/c5dt00960j ◽

2015 ◽

Vol 44 (29) ◽

pp. 13242-13249 ◽

Cited By ~ 28

Author(s):

Malay Dolai ◽

Mahammad Ali ◽

Ján Titiš ◽

Roman Boča

Keyword(s):

Schiff Base ◽

Single Molecule ◽

Schiff Base Ligand ◽

Magnetic Relaxation ◽

Magnetic Behaviour ◽

Dinuclear Complexes ◽

Relaxation Processes ◽

Single Molecule Magnets ◽

Slow Magnetic Relaxation

Two CuII–DyIII and CoIII–DyIII dinuclear complexes of a Schiff base ligand (H3L) exhibit single-molecule magnetic behaviour with multiple slow magnetic relaxation processes for the former.

Download Full-text

Magnetic anisotropy on demand exploiting high-pressure as remote control: an ab initio proof-of-concept

Dalton Transactions ◽

10.1039/d1dt01719e ◽

2021 ◽

Author(s):

Matteo Briganti ◽

Federico Totti

Keyword(s):

High Pressure ◽

High Temperature ◽

Remote Control ◽

Magnetic Anisotropy ◽

Ab Initio ◽

Single Molecule ◽

Boiling Temperature ◽

Proof Of Concept ◽

Single Molecule Magnets ◽

On Demand

Lanthanide based single molecule magnets have recently become very promising systems for creating single molecule device working at high temperature (nitrogen boiling temperature). However, the variation of direction of the...

Download Full-text

Effect of high hydrostatic pressure and high-pressure homogenisation on Lactobacillus plantarum inactivation kinetics and quality parameters of mandarin juice

European Food Research and Technology ◽

10.1007/s00217-010-1381-9 ◽

2010 ◽

Vol 232 (2) ◽

pp. 265-274 ◽

Cited By ~ 29

Author(s):

J. M. Carreño ◽

M. C. Gurrea ◽

F. Sampedro ◽

J. V. Carbonell

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

Lactobacillus Plantarum ◽

High Hydrostatic Pressure ◽

Quality Parameters ◽

Inactivation Kinetics ◽

Mandarin Juice

Download Full-text

Effect of High Hydrostatic Pressure on Salmonella Inoculated into Creamy Peanut Butter with Modified Composition

Journal of Food Protection ◽

10.4315/0362-028x.jfp-14-062 ◽

2014 ◽

Vol 77 (10) ◽

pp. 1664-1668 ◽

Cited By ~ 5

Author(s):

TANYA D'SOUZA ◽

MUKUND KARWE ◽

DONALD W. SCHAFFNER

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

Water Activity ◽

High Hydrostatic Pressure ◽

Peanut Butter ◽

High Pressure Processing ◽

Peanut Oil ◽

Peanut Flour ◽

Log Reduction ◽

High Hydrostatic Pressure Processing

Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

Download Full-text

High-Pressure Inactivation of Hepatitis A Virus within Oysters

Applied and Environmental Microbiology ◽

10.1128/aem.71.1.339-343.2005 ◽

2005 ◽

Vol 71 (1) ◽

pp. 339-343 ◽

Cited By ~ 114

Author(s):

Kevin R. Calci ◽

Gloria K. Meade ◽

Robert C. Tezloff ◽

David H. Kingsley

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Hepatitis A ◽

Hepatitis A Virus ◽

Natural Conditions ◽

Direct Evaluation ◽

Temperature Range

ABSTRACT Previous results demonstrated that hepatitis A virus (HAV) could be inactivated by high hydrostatic pressure (HHP) (D. H. Kingsley, D. Hoover, E. Papafragkou, and G. P. Richards, J. Food Prot. 65:1605-1609, 2002); however, direct evaluation of HAV inactivation within contaminated oysters was not performed. In this study, we report confirmation that HAV within contaminated shellfish is inactivated by HHP. Shellfish were initially contaminated with HAV by using a flowthrough system. PFU reductions of >1, >2, and >3 log10 were observed for 1-min treatments at 350, 375, and 400 megapascals, respectively, within a temperature range of 8.7 to 10.3Ã¯Â¿Â½C. Bioconcentration of nearly 6 log10 PFU of HAV per oyster was achieved under simulated natural conditions. These results suggest that HHP treatment of raw shellfish will be a viable strategy for the reduction of infectious HAV.

Download Full-text

Cobalt(II) chloride adducts with acetonitrile, propan-2-ol and tetrahydrofuran: considerations on nuclearity, reactivity and synthetic applications

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229617000705 ◽

2017 ◽

Vol 73 (2) ◽

pp. 104-114 ◽

Cited By ~ 1

Author(s):

Danilo Stinghen ◽

André Luis Rüdiger ◽

Siddhartha O. K. Giese ◽

Giovana G. Nunes ◽

Jaísa F. Soares ◽

...

Keyword(s):

Single Molecule ◽

Building Blocks ◽

Direct Reaction ◽

X Ray Diffraction ◽

Single Molecule Magnets ◽

X Ray ◽

Ft Ir ◽

Bond Network ◽

Solvent Molecules ◽

Intramolecular Hydrogen

High-spin cobalt(II) complexes are considered useful building blocks for the synthesis of single-molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl2, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single-crystal X-ray diffraction analyses.trans-Tetrakis(acetonitrile-κN)bis(tetrahydrofuran-κO)cobalt(II) bis[(acetonitrile-κN)trichloridocobaltate(II)], [Co(C2H3N)4(C4H8O)2][CoCl3(C2H3N)]2, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymercatena-poly[[tetrakis(propan-2-ol-κO)cobalt(II)]-μ-chlorido-[dichloridocobalt(II)]-μ-chlorido], [Co2Cl4(C3H8O)4], (2′), was prepared by direct reaction between anhydrous CoCl2and propan-2-ol in an attempt to rationalize the formation of the CoCl2–alcohol adduct (2), probably CoCl2(HOiPr)m. The binuclear complex di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-2κ2Cl-tetrakis(tetrahydrofuran-1κO)dicobalt(II), [Co2Cl4(C4H8O)4], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen-bond network that appears to favour atransarrangement of the chloride ligands in the octahedral moiety; this differs from thecisdisposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.

Download Full-text

Effect of high pressure on various diffusion mechanisms in oxygen-deficient ReBa2Cu3O7−x (Re = Y, Ho) single crystals

Modern Physics Letters B ◽

10.1142/s0217984919500398 ◽

2019 ◽

Vol 33 (04) ◽

pp. 1950039

Author(s):

G. Ya. Khadzhai ◽

N. R. Vovk ◽

R. V. Vovk ◽

I. L. Goulatis ◽

O. V. Dobrovolskiy

Keyword(s):

High Pressure ◽

Electrical Resistivity ◽

Hydrostatic Pressure ◽

Single Crystals ◽

High Hydrostatic Pressure ◽

Room Temperature ◽

Diffusion Mechanisms ◽

Diffusion Coalescence

The effect of high hydrostatic pressure on the relaxation of the electrical resistivity at room temperature of oxygen-nonstoichiometric [Formula: see text] (Re = Y, Ho) single crystals is investigated. The application of hydrostatic pressure has been revealed to significantly intensify the process of diffusion coalescence in the oxygen subsystem. At the same time, the intensity of the redistribution of labile oxygen is significantly changed when yttrium is replaced by holmium.

Download Full-text