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Mn2CoReO6, the fourth known magnetic transition-metal-only double perovskite oxide (space group P21/n) was synthesized at high pressure and temperature (8 GPa, 1350 °C). Large structural distortions are induced by the small A-site Mn2+ cations. Mn2CoReO6 exhibits complex magnetic properties with a robust antiferromagnetic order (TN = 94 K) involving all cation sublattices.

This work investigates the effect of different anti-solvents (water, ethanol, or both water and ethanol) on the characteristics of cellulose dissolved and then generated from 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]). Compared with original microcrystalline cellulose (MCC) granules, all regenerated celluloses showed a homogeneous, agglomerated macromorphology and had its crystalline structure transformed from original cellulose I to cellulose II. The regenerated cellulose using water (43.3%) had a higher degree of crystallinity than that using ethanol (13.5%), and a degree of crystallinity of 21.3% was obtained when an ethanol-water-ethanol treatment method was used. SAXS and FTIR results indicate that water as an anti-solvent could promote the rearrangement of cellulose molecular chains and the rebuilding of an ordered aggregated structure. Moreover, the regenerated cellulose with water showed better thermal stability than that of the samples regenerated using ethanol. Thus, our results suggest that the reconstitution of cellulose molecules during regeneration with various anti-solvents can affect the multiscale structures and properties of cellulose., (Copyright © 2018. Published by Elsevier B.V.)

Rare-earth cobalt pnictides, RCo 2 Pn 2 (Pn = P, As), belong to the ThCr 2 Si 2 structure type, which is ubiquitous among intermetallic compounds. The structural and magnetic properties of simple ternary RCo 2 P 2 phosphides, which combine partially delocalized (itinerant) 3d magnetic moments of cobalt and localized 4f magnetic moments of lanthanides, were investigated extensively in 1980-1990s, predominantly by the Jeitschko group. Those studies established that LaCo 2 P 2 shows ferromagnetic (FM) ordering of Co moments, while the other members of the series, with R = Ce, Pr, Nd, or Sm, exhibit antiferromagnetic (AFM) ordering in both R and Co magnetic sublattices. This observation also correlated with the larger separation between the [Co 2 P 2 ] layers in the crystal structure of LaCo 2 P 2 as compared to the decreased interlayer distances in the other structures of the RCo 2 P 2 series. Our work over the past decade has focused on unraveling the rich magnetic behavior that can be observed in these systems when internal chemical and external physical factors are used to perturb their crystal and electronic structures. We began our foray into these materials by demonstrating that the preservation of FM ordering of Co 3d moments in the mixed La 1-x R' x Co 2 P 2 phases also forces the R 4f moments to adopt FM arrangement, although antiparallel to the Co moments. As an example, in La 0.75 Pr 0.25 Co 2 P 2 such mutual influence of the 3d and 4f moments leads to a cascade of magnetic phase transitions. All these changes were traced back to the modification of the crystal structure and, consequently, the electronic band structure of these materials. The substitution of smaller R 3+ ions for the La 3+ ions leads to structural compression along the tetragonal c axis, perpendicular to the [Co 2 P 2 ] layers, and an increase in the Co-Co distances within the layer. This structural effect is translated into more localized Co magnetic moments, stronger magnetic exchange between Co sites, and higher ordering temperatures. A more dramatic change in properties is observed in EuCo 2 Pn 2 , which exhibit AFM ordering of the localized 4f moments of Eu 2+ ions and only paramagnetic behavior in the Co sublattice. Under applied pressure, these compounds undergo structural collapse, which causes a dramatic decrease in the separation between the [Co 2 Pn 2 ] layers, an increase in the oxidation state of Eu, and magnetic ordering of Co moments. We further demonstrated that similar effects can be stimulated by chemical compression, which is achieved by doping Eu into the more constrained lattice sites, for example, in PrCo 2 P 2 or CaCo 2 As 2 . In both cases, the induced mixed valence of Eu results in the change from AFM to FM ordering in the Co sublattice. A series of solid solutions Ca 1-x Eu x Co 2 As 2 shows a fascinating evolution of magnetic behavior from AFM ordering of Co 3d moments to simultaneous FM ordering of Co 3d and Eu 4f moments to AFM ordering of Eu 4f moments as one proceeds from CaCo 2 As 2 to EuCo 2 As 2 . Importantly, all these changes in magnetic properties are well justified by the analysis of electronic density of states and crystal orbital Hamilton population, providing the understanding of how chemical factors can be leveraged, in general, to modify properties of itinerant magnets.

Starches were isolated from South China 5 (SC5) cassava harvested for 7, 8, 9, 10 and 11 months. During growth, the granule size, lamellar structure, crystalline structure and digestibility changed slightly, while the amylose content varied between 20.93% and 22.61%. However, the molecular weight showed an obvious increase as the harvesting time increased to 9 months, and then decreased during 9-11 months. The pasting behaviors were greatly affected by harvesting time. A shorter growth time led to higher pasting temperature, and lower peak, breakdown and setback viscosities. This trend became contrary when the growth time prolonged from 9 to 11 months. Hence, the starch harvested at 9 months showed the lowest pasting temperature (64.6°C), but highest paste viscosity (2105cP) and retrogradation tendency. All these results confirm that the growth time of 9 months was the turning point for the physicochemical features of SC5 during growth. This study provides fundamental data for rationally tailoring cassava starch properties by simply controlling the harvest time., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Breadfruit starch was subjected to heat-moisture treatment (HMT) at different moisture content (MC). HMT did not apparently change the starch granule morphology but decreased the molecular weight and increased the amylose content. With increased MC, HMT transformed the crystalline structure (B→A+B→A) and decreased the relative crystallinity. With ≥25% MC, the scattering peak at ca. 0.6nm -1 disappeared, suggesting the lamellar structure was damaged. Compared with native starch, HMT-modified samples showed greater thermostability. Increased MC contributed to a higher pasting temperature, lower viscosity, and no breakdown. The pasting temperature of native and HMT samples ranged from 68.8 to 86.2°C. HMT increased the slowly-digestible starch (SDS) and resistant starch (RS) contents. The SDS content was 13.24% with 35% MC, which was 10.25% higher than that of native starch. The increased enzyme resistance could be ascribed to the rearrangement of molecular chains and more compact granule structure., (Copyright © 2017 Elsevier Ltd. All rights reserved.)