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Aerogel-Based Single-Ion Magnets: A Case Study of a Cobalt(II) Complex Immobilized in Silica. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28010418. [PMID: 36615607 PMCID: PMC9824035 DOI: 10.3390/molecules28010418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/15/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023]
Abstract
The chemical immobilization of cobalt(II) ions in a silica aerogel matrix enabled the synthesis of the first representative example of aerogel-based single-ion magnets. For the synthesis of the lyogels, methyl-trimethoxysilane and N-3-(trimethoxysilyl)propyl ethylenediamine were co-hydrolyzed, then the ethylenediamine groups that were immobilized on the silica matrix enabled the subsequent binding of cobalt(II) ions. Lyogels with various amounts of ethylenediamine moieties (0.1-15 mol %) were soaked in isopropanol solutions of cobalt(II) nitrate and further supercritically dried in carbon dioxide to obtain aerogels with a specific surface area of 210-596 m2·g-1, an apparent density of 0.403-0.740 cm3·g-1 and a porosity of 60-78%. The actual cobalt content in the aerogels was 0.01-1.50 mmol per 1 g of SiO2, which could easily be tuned by the concentration of ethylenediamine moieties in the silica matrix. The introduction of cobalt(II) ions into the ethylenediamine-modified silica aerogel promoted the stability of the diamine moieties at the supercritical drying stage. The molecular prototype of the immobilized cobalt(II) complex, bearing one ethylenediamine ligand [Co(en)(MeCN)(NO3)2], was synthesized and structurally characterized. Using magnetometry in the DC mode, it was shown that cobalt(II)-modified silica aerogels exhibited slow magnetic relaxation in a nonzero field. A decrease in cobalt(II) concentration in aerogels from 1.5 mmol to 0.14 mmol per 1 g of SiO2 resulted in a weakening of inter-ion interactions; the magnetization reversal energy barrier likewise increased from 4 to 18 K.
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Lazhko AE, Kostenko MO, Lagunova EA, Parenago OO, Bragina GO, Parenago OP. Formation of Metal–Hypercrosslinked Polystyrene Composites in a Supercritical Carbon Dioxide Medium and Their Catalytic Properties in the Hydrogenation of Diphenylacetylene. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2022. [DOI: 10.1134/s1990793122070119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Straumal EA, Gozhikova IO, Kottsov SY, Lermontov SA. Effect of Sol Concentration on Properties of Alumina Aerogels. RUSS J INORG CHEM+ 2022. [DOI: 10.1134/s003602362260071x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yorov KE, Baranchikov AE, Kiskin MA, Sidorov AA, Ivanov VK. Functionalization of Aerogels with Coordination Compounds. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422020014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Si-Hung L, Bamba T. Current state and future perspectives of supercritical fluid chromatography. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116550] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kostenko M, Parenago O. Adsorption of N,N,N′,N′-Tetraoctyl Diglycolamide on Hypercrosslinked Polysterene from a Supercritical Carbon Dioxide Medium. Molecules 2021; 27:molecules27010031. [PMID: 35011262 PMCID: PMC8746298 DOI: 10.3390/molecules27010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
The work considers for the first time the preparation of sorbents based on hypercrosslinked polysterene (HCP) and chelating agent N,N,N′,N′-tetraoctyl diglycolamide (TODGA) by impregnation in the supercritical (SC) CO2 medium. Such sorbents can be applied for further isolation and separation of lanthanides, actinides and other metals. They are usually prepared by impregnation in toxic organic solvents (e.g., methanol, dichloromethane). Our study shows that application of SC CO2 instead of organic solvents can significantly speed up the impregnation, perfom it in one stage and make the process more eco-friendly. At the same time, the obtained sorbents are close in their parameters to the classical ones. This article presents the results of measuring the TODGA adsorption isotherms on two HCP sorbents (MN202 and MN270) on a wide range of SC fluid parameters. Adsorption measurements were carried out using on-line supercritical fluid chromatography and gravimetry. Based on the sorption capacity parameter, MN202 sorbent was selected as the better carrier for TODGA. An impregnation temperature increase within the range 313–343 K in isochoric conditions (ρ = 0.780 g/mL) reduces the maximum of TODGA adsorption from ~0.68 mmol/g to ~0.49 mmol/g.
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Affiliation(s)
- Mikhail Kostenko
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospect 31, 119071 Moscow, Russia;
- Correspondence:
| | - Olga Parenago
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospect 31, 119071 Moscow, Russia;
- Chemistry Department, Moscow State University, Leninskie Gory 1, Bldg. 3, 119234 Moscow, Russia
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Gromov OI, Kostenko MO, Petrunin AV, Popova AA, Parenago OO, Minaev NV, Golubeva EN, Melnikov MY. Solute Diffusion into Polymer Swollen by Supercritical CO 2 by High-Pressure Electron Paramagnetic Resonance Spectroscopy and Chromatography. Polymers (Basel) 2021; 13:polym13183059. [PMID: 34577959 PMCID: PMC8466873 DOI: 10.3390/polym13183059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/31/2021] [Accepted: 09/06/2021] [Indexed: 11/16/2022] Open
Abstract
High-pressure electron paramagnetic resonance (EPR) was used to measure translational diffusion coefficients (Dtr) of a TEMPONE spin probe in poly(D,L-lactide) (PDLLA) and swollen in supercritical CO2. Dtr was measured on two scales: macroscopic scale (>1 μm), by measuring spin probe uptake by the sample; and microscopic scale (<10 nm), by using concentration-dependent spectrum broadening. Both methods yield similar translational diffusion coefficients (in the range 5-10 × 10-12 m2/s at 40-60 °C and 8-10 MPa). Swollen PDLLA was found to be homogeneous on the nanometer scale, although the TEMPONE spin probe in the polymer exhibited higher rotational mobility (τcorr = 6 × 10-11 s) than expected, based on its Dtr. To measure distribution coefficients of the solute between the swollen polymer and the supercritical medium, supercritical chromatography with sampling directly from the high-pressure vessel was used. A distinct difference between powder and bulk polymer samples was only observed at the start of the impregnation process.
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Affiliation(s)
- Oleg I. Gromov
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia; (A.A.P.); (O.O.P.); (E.N.G.); (M.Y.M.)
- Correspondence:
| | - Mikhail O. Kostenko
- Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russia;
| | | | - Anastasia A. Popova
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia; (A.A.P.); (O.O.P.); (E.N.G.); (M.Y.M.)
| | - Olga O. Parenago
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia; (A.A.P.); (O.O.P.); (E.N.G.); (M.Y.M.)
- Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, Russia;
| | - Nikita V. Minaev
- Federal Scientific Research Centre “Crystallography and Photonics” RAS, Institute of Photon Technologies, Pionerskaya Str. 2, Troitsk, 108840 Moscow, Russia;
| | - Elena N. Golubeva
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia; (A.A.P.); (O.O.P.); (E.N.G.); (M.Y.M.)
| | - Mikhail Ya. Melnikov
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskiye Gory, 1-3, 119991 Moscow, Russia; (A.A.P.); (O.O.P.); (E.N.G.); (M.Y.M.)
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A Doubly Green Separation Process: Merging Aqueous Two-Phase Extraction and Supercritical Fluid Extraction. Processes (Basel) 2021. [DOI: 10.3390/pr9040727] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Aqueous two-phase extraction (ATPE) is a green separation technique which uses mixtures of water and environmentally benign polymers such as polyethylene glycol (PEG) as solvents. One of the challenges in implementing this extraction on an industrial scale is finding a suitable method for the isolation of target compounds from water-polymer solutions after the extraction, without diminishing ecological benefits of the method. In this paper, we propose using another green separation technique, supercritical fluid extraction (SFE), for the back-extraction of low molecular weight medium polarity compounds from ATPE solutions. Experiments with two model compounds, caffeine and benzoic acid, showed principal applicability of SFE for this task. Pressure (100–300 bar) and temperature (35–75 °C) of supercritical carbon dioxide play a major role in defining extraction capability. Extraction ratios of 35% for caffeine and 42% for benzoic acid were obtained at high fluid pressure and moderate temperature at 1:6 volume phase ratio. That gives an estimation of 10–20 theoretical steps required for complete exhaustive extraction from the ATPE solution, which is readily achievable in standard counter-current column SFE. Combining these two green methods together not only serves as an environmentally friendly method for the isolation of valuable low molecular weight compounds from diluted water solutions, but also allows for simple, energy effective recuperation of ATPE solvents.
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