Synthesis and structure of new europium(ɪɪɪ) and terbium(ɪɪɪ) coordination polymers with trans-1,4-cyclohexanedicarboxylic acid

Russian Chemical Bulletin - Two new metal-organic frameworks of composition [Eu2(phen)2Cl2(chdc)2] ? 1.1DMF? ?0.7diox (1?1.1DMF?0.7diox, phen is 1,10-phenanthroline,...     

Enantioselective microbial synthesis of (<Emphasis Type="Italic">S</Emphasis>)-7,8-difluoro-3,4-dihydro-3-methyl-2<Emphasis Type="Italic">H</Emphasis>-[1,4]benzoxazine

New strains of Rhodococcus erythropolis 25 and Microbacterium paraoxydans 20-11c actinobacteria were used to obtain (S)-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine (99.6% ee) by enantioselective microbial hydrolysis of the corresponding racemic N-acetyl derivative.     

Diffusion of As ions and self-diffusion in silicon during implantation

Experimental concentration profiles of As ions in a silicon substrate at temperatures of 20, 600, and 1050°C and ion current of 40 μA/cm², as well as at 1050°C and 10 μA/cm², are presented. On the basis of our and previously published experimental data, the process of radiation-stimulated ionic diffusion and self-diffusion in silicon is simulated. A number of interesting dependences, which are discussed in the conclusion of this study, are obtained.     

CRYSTAL STRUCTURE OF COORDINATION COBALT(II) AND ZINC(II) POLYMERS WITH 1,4-DIAZABICYCLO[2.2.2]OCTANE N,N′-DIOXIDE

Journal of Structural Chemistry - Four cobalt(II) and zinc(II) cationic metal-organic frameworks (MOFs) based on bridging 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco) are synthesized....     

Cinnamal Sensing and Luminescence Color Tuning in a Series of Rare-Earth Metal−Organic Frameworks with Trans-1,4-cyclohexanedicarboxylate

Three isostructural metal–organic frameworks ([Ln₂(phen)₂(NO₃)₂(chdc)₂]·2DMF (Ln³⁺ = Y³⁺ for 1, Eu³⁺ for 2 or Tb³⁺ for 3; phen = 1,10-phenanthroline; H₂chdc = trans-1,4-cyclohexanedicarboxylic acid) were synthesized and characterized. The compounds are based on a binuclear block {M₂(phen)₂(NO₃)₂(OOCR)₄} assembled into a two-dime nsional square-grid network containing tetragonal channels with 26% total solvent-accessible volume. Yttrium (1)-, europium (2)- and terbium (3)-based structures emit in the blue, red and green regions, respectively, representing the basic colors of the standard RGB matrix. A doping of Eu³⁺ and/or Tb³⁺ centers into the Y³⁺-based phase led to mixed-metal compositions with tunable emission color and high quantum yields (QY) up to 84%. The bright luminescence of a suspension of microcrystalline 3 in DMF (QY = 78%) is effectively quenched by diluted cinnamaldehyde (cinnamal) solutions at millimolar concentrations, suggesting a convenient and analytically viable sensing method for this important chemical.     

METAL-ORGANIC COORDINATION POLYMERS OF LANTHANIDES(III) WITH THIENOTHIOPHENDICARBOXYLATE LIGANDS

Journal of Structural Chemistry - Three novel metal-organic coordination polymers based on sulfur-containing thieno[3,2-b]thiophene-2,5-dicarboxylic (trans-H2ttdc) and...     

Zinc(II) metal-organic frameworks with 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide: control of the parameters of the cationic porous framework and optical properties

Russian Chemical Bulletin - Four zinc metal-organic frameworks (MOFs) with 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide (odabco) as a bridging ligand were synthesized by varying the solvent and...     

Synthesis and structure of manganese(ii) coordination polymers with 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide: solvent and template effects

Russian Chemical Bulletin - New metal-organic frameworks [Mn(DMF)2(odabco)2](ClO4)2 · H2O (1), [Mn(H2O)2? (HCOO)2] · odabco (2), and [Mn(Hodabco)2(odabco)3](NO3)4 (3) were...     

Heat-resistant alloys based on intermetallic Co<Subscript>3</Subscript>(Al,W)

The structures and phase compositions of a series of Co–9 at % Al–x at % W alloys (where x = 4.6, 6.8, 8.5, 10.0, 12.6) have been studied. All of them are dominated by the structure γ + γ′, with the content of other phases (the μ phase and the phase D0₁₉ based on Co₃W) being insignificant. With increasing tungsten content of the alloy (to 10 at % W), the volume fraction of the γ′ phase increases, and so does its degree of long-range order. The alloy that is optimal in structure and mechanical properties has the composition Co–8.2 at % Al–8.5 at % W. The dissolution range of the γ′ phase was determined as 920–1054°C. Young’s moduli of cobalt alloys exceed E of commercial nickel-based superalloys. The samples of the studied alloys are in the ferromagnetic state with a Curie temperature of 870°C. With increasing tungsten content of the alloy, its saturation magnetization decreases and the coercive force increases. The coercive force is minimal in an as-cast sample and increases as it is subjected to deformation or heat treatment.