| 1. |
- Mishra, Manish Kumar, et al.
(författare)
-
CO2 capture from ambient air via crystallization with tetraalkylammonium hydroxides
- 2022
-
Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 51:46, s. 17724-17732
-
Tidskriftsartikel (refereegranskat)abstract
- Aqueous solutions of a series of short carbon chain tetra(n-alkyl)ammonium hydroxides, [Nnnnn][OH] with n = 2: n-ethyl, 3: n-propyl, 4: n-butyl, have been serendipitously found to be potential candidates for direct air carbon capture (DAC) when being used as reagents in more complicated reactions. Aqueous solutions of [N3333][OH], [N2222][OH], or [N3333][OH] with UO2SO4·3H2O and 1,4-diamidoximylbenzene, and [N4444][OH] with cytosine (HCyt) directly absorb CO2 from the atmosphere upon mild heating in the open atmosphere crystallizing in complexes reaching up to 2 : 1 CO2/[Nnnnn]OH ratio. [N2222][HCO3]·3H2O (1), [N2222]2[H(HCO3)3]·5H2O (2), [N3333][HCO3]·0.5H2O (3), [N3333][H(HCO3)2] (4), [N3333]2[(tpa)(H2CO3)2] (5; tpa = terephthalate), [N4444][H(Cyt)(HCO3)]·H2O (6) and [N4444][H2(Cyt)2(HCO3)]·H2O (7) have been isolated in crystalline form and structurally characterized by single crystal X-ray diffraction. The compounds are characterized by complex polyanionic formations from bicarbonate dimers ([(HCO3)2·(H2O)]24−) or chains ([H(HCO3)2]nn− or [H2(tpa)(HCO3)2]n2n−) to water-bicarbonate associates ([(HCO3)2·6H2O]2− and [(H2CO3·(HCO3)2)2·6H2O·2H2O]2−) and three-component anionic layers ([H(Cyt)(HCO3)·H2O]nn− and [H2(Cyt)2(HCO3)·H2O]nn−) frequently showing proton sharing. While some hydroxides themselves can maintain a high CO2/[Nnnnn][OH] ratio, particularly 2 and 4, the presence of secondary hydrogen bond donors/acceptors may increase the sorption efficiency through decreased solubility and enhanced crystallization.
|
|
| 2. |
- Wineinger, Hannah B., et al.
(författare)
-
Accessing Lanthanide Tricyanomethanide Coordination Polymers Using Ionic Liquids
- 2022
-
Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 22:4, s. 2372-2381
-
Tidskriftsartikel (refereegranskat)abstract
- In contrast to alkaline, alkaline earth, and transition metals, tricyanomethanide complexes of f-elements are largely underexplored mainly due to synthetic challenges originating from the harder Lewis acidic character of the trivalent cations; only one crystal structure of an f-element-tricyanomethanide complex has ever been reported. Here, we report that by using the tricyanomethanide-based ionic liquids (ILs) 1-butyl-4-methylpyridinium tricyanomethanide ([C4mpyrid][TCM]) or 1-ethyl-3-methylimidazolium tricyanomethanide ([C2mim][TCM]), we have identified a way to begin building a library of 1D and 2D lanthanide/tricyanomethanide coordination polymers, although not yet in an optimized, controllable fashion. Saturation of NdX3·6H2O (X = Cl– or [NO3]−) over 100 °C in [C4mpyrid][TCM] or [C2mim][TCM] followed by slow cooling allowed for the crystallization of [C2mim]n[Nd(NO3)2(μ3-TCM)(μ2-TCM)(OH2)]n (1), [C4mpyrid]2n[Nd(μ2-Cl)Cl2(μ2-TCM)(TCM)(OH2)]n (2), [C4mpyrid]n[Nd(μ2-TCM)2(TCM)2(OH2)3]n (3), and [C4mpyrid]n[NdCl2(μ2-TCM)2(OH2)2]n (4) as anionic chains (2, 4) or layers (1, 3). Compound 3 could be isolated either by saturation and heating of Nd(NO3)3·6H2O or by reheating the reaction mixture leading to 2. The use of [TCM]−-based ILs as solvent and sources of the coordinating ligand provides a method to promote f-element-[TCM]− complexation without the use of competing O-donor solvents or high temperatures, potentially opening a new route to structurally characterize [TCM]− complexes of the entire lanthanide series. Although these products were not synthesized in high yields, their isolation provides clues on how to modify and optimize the syntheses to obtain specific f-element-[TCM]− targets. This, in turn, should ultimately lead to dramatic diversification of the body of f-element-[TCM]− complexes available for study.
|
|
| 3. |
- Wineinger, Hannah, et al.
(författare)
-
Trapping an Unexpected/Unprecedented Hexanuclear Ce(III) Hydrolysis Product with Neutral 4-Amino-1,2,4-triazole
- 2023
-
Ingår i: European Journal of Inorganic Chemistry. - : WILEY-V C H VERLAG GMBH. - 1434-1948 .- 1099-1948. ; 26:31
-
Tidskriftsartikel (refereegranskat)abstract
- Using Ce(III) as both a representative lanthanide and actinide analog, the ability of mixtures of acidic and basic azoles to allow direct access to homoleptic N-donor f-element complexes in one pot reactions from hydrated salts as starting materials was examined by reacting mixtures of 4-amino-1,2,4-triazole (4-NH2-1,2,4-Triaz), 5-amino-tetrazole (5-NH2-HTetaz), and 1,2,3-triazole (1,2,3-HTriaz) in 1:1 and 1:3 ratios with CeCl3 center dot 7H(2)O, [C(2)mim](3)[CeCl6] ([C(2)mim](+) = 1-ethyl-2-methylimidazolium), and Ce(NO3)(3)center dot 6H(2)O. Although unsuccessful in our goal, structural analysis revealed that neutral 4-NH2-1,2,4-Triaz is structure directing via eta(2)mu(2)kappa(2) bridging, with the formation of the dinuclear complexes [Ce2Cl2(mu(2)-4-NH2-1,2,4-Triaz)(4)(H2O)(8)]Cl-4 center dot 4H(2)O, [Ce-2(mu(2)-4-NH2-1,2,4-Triaz)(4)(4-NH2-1,2,4-Triaz)(2)(Cl)(6)], and [4-NH2-1,2,4-HTriaz][Ce-2(mu(2)-4-NH2-1,2,4-Triaz)(2)(mu(2)-NO3)(NO3)(6)(H2O)(2)]. When the synthetic conditions favored hydrolysis, the hexanuclear Ce(III) complex [Ce-6(mu(3)-O)(4)(mu(3)-OH)(2)(mu(3)-Cl)(2)(Cl)(6)(mu(2)-4-NH2-1,2,4-Triaz)(12)]center dot 7H(2)O was isolated. This unexpected hydrolysis product represents the first example of a high nuclearity lanthanide complex where all Ln atoms are pairwise connected through 12 N-donor ligands or 12 neutral bridging ligands of any type, a rare example of incorporation of non-oxo coordinating anions in the M6X8 core, and the first reported Ce(III) hexanuclear complex of this type.
|
|
