Two new metal-organic frameworks of composition Eu
2
(phen)
2
Cl
2
(chdc)
2
• 1.1DMF• •0.7diox (
1
•1.1DMF•0.7diox, phen is 1,10-phenanthroline, DMF is
N,N
-dimethyl-formamide, diox is dioxane) and ...Tb
2
(phen)
2
Cl
2
(chdc)
2
• 2diox • 2H
2
O (
2
• 2diox • 2H
2
O) were synthesized using the conformationally flexible alicyclic ligand, trans-1,4-cyclohexane-dicarboxylic acid (H
2
chdc). The mononuclear complex Tb(phen)
2
(DEF)(H
2
O)Cl
2
Cl (
3
, DEF is
N,N
-diethylformamide) was also prepared. The structures of the reaction products were determined by single-crystal X-ray diffraction. The compositions and nature of the compounds
1
• 0.6DMF• 2.5H
2
O and
2
• 0.5diox • 4H
2
O, which were obtained after the separation of single crystals from the mother liquor, were confirmed by IR spectroscopy, elemental analysis, and thermogravimetric analysis. Both these compounds are composed of the binuclear units {Ln
2
(phen)
2
Cl
2
(O
2
CR)
4
} and are rare examples of the coordination of a halide anion to the Ln
III
ion in the metal-organic framework. The three-dimensional packing of the layers in the structures of
1
and
2
contains voids with a total volume of 35 and 32%, respectively.
The approach, combining metal–organic frameworks and functional guests such as proton conductors of MmHn(XO4)p family has been proposed and successfully realized in the (1−x)CsHSO4–xCr-MIL-101 ...nanocomposites.
The (1−x)CsHSO4–xCr-MIL-101 (x=0–0.07) hybrid compounds with unusual transport, structural and thermodynamic properties have been synthesized and investigated by impedance, infrared spectroscopy and XRD methods. The addition of the nonconducting matrix to CsHSO4 results in decrease of the temperature of superionic phase transition and considerable increase (up to 2 orders of magnitude) of proton conductivity of CsHSO4 in low temperature phase due to its disordered state in cavities of Cr-MIL-101 with the maximum conductivity at x=0.02–0.04. As a result (1−x)CsHSO4–xCr-MIL-101 nanocomposites have proton conductivity 10−7–10−2S/cm at temperatures 50–200°C and thermal stability up to 190°C. Nanocomposite effect is similar to known CsHSO4–SiO2 and CsHSO4–TiO2 systems, however is not so high. The used approach may be perspective for the other composite systems with proton conductivity.
► Proton conductors based on CsHSO4 and crystalline metal -organic framework. ► The new approach based on combining metal–organic frameworks and functional gests from acid salt family has been proposed. ► Transport, structural and thermodynamic properties of proton nanocomposites based on Cr MIL -101 and CsHSO4 have been investigated first.
The reactions of magnesium nitrate with
trans
-1,4-cyclohexanedicarboxylic acid (H
2
Сhdc) in
N
,
N
-dimethylformamide (DMF) and
N
-methylpyrrolidone (NMP) as solvents afford new coordination ...polymers Mg
3
(DMF)
4
(Chdc)
3
(
I
), Mg
3
(DMF)
2
(NMP)
2
(Сhdc)
3
(
II
), and Mg
3
(NMP)
4
(Сhdc)
3
(
III
). Coordination polymer Ca
3
(NMP)
4
(Chdc)
3
(
IV
) is synthesized from calcium acetate and H
2
Chdc in NMP. The reaction of cadmium nitrate with H
2
Сhdc and urotropine (Ur) in DMF gives coordination polymer Cd(Ur)(DMF)(Chdc) (
V
). The structures of the synthesized compounds are determined by single-crystal X-ray diffraction (XRD) (CIF files CCDC nos. 2120662 (
I
), 2120666 (
II
), 2120664 (
III
), 2120663 (
IV
), and 2120665 (
V
)). The coordination polymers of alkaline-earth metals (
I
–
IV
) are based on trinuclear carboxylate blocks {M
3
(OOC)
6
} linked by the dicarboxylate linkers into trigonal layers. The cadmium compound (
V
) is built of the mononuclear fragments {Cd(N
Ur
)
2
(DMF)(OOC)
2
} linked by bridging
trans
-1,4-cyclohexanedicarboxylates and urotropine molecules into polymer layers. Compounds
I
–
III
are characterized by IR spectroscopy, elemental analysis, and thermogravimetric analysis.
The first example of a coordination polymer with a triply charged metal ion is obtained based on the conformationally mobile bridging ligand 1,4-diazabicyclo2.2.2octane N,N′-dioxide (odabco). Its ...structure is characterized by single crystal X-ray diffraction. The compound has the formula La(odabco)
3
Cl
3
·
x
H
2
O (
1
) with a variable hydration number and is composed of six-coordinated octahedral La
3+
sites. The 3D cationic coordination lattice of
1
has a primitive cubic (
pcu
) topology and contains isolated voids with a total specific volume of 28% filled with chloride anions and water molecules. The compound is characterized by powder XRD and elemental analysis. The absence of absorption maxima in the visible and UV ranges up to 270 nm is shown by diffuse reflectance spectroscopy for
1
.
Four zinc metal-organic frameworks (MOFs) with 1,4-diazabicyclo2.2.2octane
N,N′
-dioxide (odabco) as a bridging ligand were synthesized by varying the solvent and the anionic composition of the ...reaction medium. The synthesis in a mixture of
N, N
-dimethylacetamide and water acidified with nitric acid affords the compound Zn
2
(odabco)
3
(OAc)
2
(NO
3
)
2
(1)
containing coordinated acetate anions. The compound Zn
2
(μ-
O
)(odabco)
3
(NO
3
)
2
· NMP · 2H
2
O
(2)
crystallizes in a mixture of
N
-methylpyrrolidone (NMP) and water in the presence of triethylamine as the base. The compound Zn
2
(odabco)
4
(NO
3
)
3
(ClO
4
) · 2 DMF
(3)
was obtained in
N,N
-dimethylformamide (DMF) acidified with perchloric acid. The synthesis in a mixture of DMF and dioxane (dox) acidified with a larger amount of perchloric acid produces Zn(odabco)
2
(NO
3
)(ClO
4
) · 0.4 dox
(4).
The crystal structures of new compounds
2–4
were determined by single-crystal X-ray diffraction. Compound
2
consists of binuclear {Zn
2
O}
2+
units, serving as nodes in the three-dimensional framework with
pcu
topology and a solvent-accessible volume (
V
pore
) of 37%. The isomeric metal-organic coordination frameworks of
3
(
V
pore
= 42%) and
4
(
V
pore
= 47%) are built from mononuclear units and have a BCT zeolite topology. The optical absorption of compounds
1–4
was characterized by diffuse reflectance spectroscopy.
Target Chamber for Simulation Experiments Pryanishnikov, K. E.; Fedin, P. A.; Semyachkin, V. K. ...
Physics of atomic nuclei,
12/2022, Letnik:
85, Številka:
11
Journal Article
Recenzirano
A target chamber has been developed and manufactured for carrying out simulation experiments with two simultaneous beams of heavy and light ions. The target chamber is equipped with elements for beam ...diagnostics and target-temperature control. The chamber allows the installation of plasma cleaning systems and nitrogen trap.
High-temperature superconducting (HTS) composite tapes of the second generation are promising materials for the development of sources of high magnetic fields, including for accelerators and ...tokamaks, where superconductors can be exposed to radiation for a long time. Such an impact causes defects in superconductors, the presence of which can both decrease the current-carrying capacity of the HTS due to the degradation of the superconducting layer and increase it due to the formation of additional pinning centers for magnetic field vortices. In this work, we simulated the processes of defect formation in a single tape and a stack of 10 HTS tapes upon irradiation with protons with an energy of
E
= 6–20 MeV. The results were verified experimentally by irradiating a stack of 10 HTS tapes with protons with an energy of
E
= 6 MeV and a fluence of up to 5 × 10
15
cm
–2
. For experimental studies, an industrial SuperOx HTS tape with a double-sided copper coating 20 µm thick was used. Upon irradiation with 6-MeV protons, the radiation does not pass through a single tape, which is confirmed by the fact that the critical current of the superconductor drops only in the first layer of a stack of HTS tapes, and the value of the critical temperature for this layer differs by less than 0.5% compared to the nonirradiated tape. We concluded that in real systems, HTS tapes can be easily protected from radiation with an energy of
E
= 6 MeV, but as the energy increases, a more complex protection design is required.
The resource of nuclear facilities is largely limited by the degradation of structural or functional materials. Under the action of high-energy neutrons, defects in the crystal lattice appear in the ...material and the accumulation of transmutation products (helium and hydrogen) occurs in the structure of the material. Qualification of structural materials using reactor irradiation takes several years, and the samples of materials themselves become activated, which makes subsequent post-reactor tests difficult. Simulation experiments on a beam of heavy ions making it possible to analyze the radiation resistance of structural materials of nuclear and fusion reactors have been carried out at the Kurchatov Complex of Theoretical and Experimental Physics (National Research Center Kurchatov Institute) since 2009. Simulation experiments at an accelerator make it possible to carry out high-dose tests in no more than a few days with control over the conditions of the irradiation (temperature of target samples, ion flux, radiation dose). The paper presents a description of the simulation irradiations carried out at the HIPr heavy ion accelerator.
Single crystals of two new inclusion compounds based on porous europium(III)
trans
-thienothiophenedicarboxylate are obtained by norbornadiene or
trans
-cinnamyl alcohol substitution for ...N,N-dimethylformamide (DMF). Their structures and compositions are determined by the single crystal X-ray diffraction analysis. The structure of Eu
2
(DMF)
4
(ttdc)
3
·3.3nbd ·1.2H
2
O (H
2
ttdc -
trans
-thienothiophenedicarboxylic acid; nbd - norbornadiene) contains directly localized nbd guest molecules. The π–π stacking interactions are found between the double bonds of norbornadiene and the heterocyclic core of the bridging ligand. The Eu
2
(H
2
O)
2
(cinol)
2
(ttdc)
3
·cinol compound contains both coordinated and guest molecules of cinnamyl alcohol (cinol). The strongest guest - host contacts without significant stacking interactions appear to be hydrogen bonds between coordinated water molecules and alcohol OH groups.
The work is devoted to the development of a low-energy beam transport (LEBT) system for a high-current multicharged ion injector based on a superconducting ECR ion source. ECR ion sources are under ...development at the Joint Institute for Nuclear Research as part of a superheavy element research program. The LEBT includes a beam analysis system. The paper describes results of simulation of ion beam dynamics in the LEBT with the ideal field approximation for optic elements.
