Publications by authors named "Woo-Taik Lim"

The perovskite quantum dots (QDs) of CsPbX (X = Cl, Br, I) exhibit exceptional photoluminescent properties, but their sensitivity to moisture and heat poses a challenge. This study presents a solvent-free synthesis approach for incorporating CsPbBr perovskite QDs into zeolite A. The introduction of [CsPbBr] perovskite QDs into the zeolite framework resulted in a highly stable configuration, maintaining its initial luminescence properties even after being underwater or exposed to heat.

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An Al13 ε-Keggin cluster, AlO4Al12(OH)24(H2O)127+, is a predominant intermediate during the hydrolysis and polymerization of aluminum as well as a highly toxic substance to plants and fishes. However, no one could clearly explain why and how a cage-like Al13 ε-Keggin cluster is formed even though it could be readily synthesized by the forced hydrolysis of Al3+. We found that the Al13 ε-Keggin cluster was spontaneously formed not in monocrystalline octosilicate but in polycrystalline magadiite by the cation-exchange reaction with unhydrolyzed Al3+.

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Amyloid materials are gaining increasing attention as promising materials for applications in numerous fields. Computational methods have been successfully implemented to investigate the structures of short amyloid-forming peptides, yet their application in the design of functional amyloid materials is still elusive. Here, we developed a computational protocol for the design of functional amyloid materials capable of binding to an ion of interest.

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Synthesis of morphologically well-defined crystals of metalloporphyrin by direct crystallization based on conventional anti-solvent crystallization method without using any additives has been rarely reported. Herein, we demonstrate an unconventional and additive-free synthetic method named reverse anti-solvent crystallization method to achieve well-defined zinc-porphyrin cube crystals by reversing the order of the addition of solvents. The extended first solvation shell effect mechanism is therefore suggested to support the synthetic process by providing a novel kinetic route for reaching the local supersaturation environment depending on the order of addition of solvents, which turned out to be critical to achieve clean cube morphology of the crystal.

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To investigate the tendency of Mn(2+)-ion exchange into zeolite Y, four single crystals of fully dehydrated Mn2+, Na(+)-exchanged zeolite Y (Si/Al = 1.56) were prepared by the exchange of Na75-Y (INa75I[Si117Al75,O384]-FAU) with aqueous of various concentrations by Mn2+ and Na+ in a total 0.05 M for molar ratios of 1:1 (crystal 1), 1:25 (crystal 2), 1:50 (crystal 3), and 1:100 (crystal 4), respectively, followed by vacuum dehydration at 400 degrees C.

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Reactions between the tripodal hydroxytriamine, 2,2-bis(aminomethyl)-3-aminopropan-1-ol, "hytame", and the isomeric pyridine aldehydes generate in all cases the tris(aminal) species based on a 1,3,5-triaza-adamantane skeleton. In all cases also, the product from water under basic conditions consists of an approximately 1:9 mixture of the triequatorial and monoaxial-diequatorial isomers. While all these tripyridyltriaza-adamantanes appear capable of acting as Lewis bases, in particular cases metal ion binding leads to a radical structural rearrangement.

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The lifetime of H2O2 is an important factor in the feasibility of Fenton's reaction for soil and groundwater remediation. The lifetime of H2O2 was evaluated in Fenton's reaction and Fenton-like reactions with haematite and magnetite. H2O2 was more stable in the Fenton-like reaction than in the Fenton's reaction.

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Selective functionalisation of the tridentate ligand 1-(2-aminoethyl)-3-methyl-3-(2-pyridyl)azetidine at its terminal amino-nitrogen atom can be readily achieved by both reductive alkylation and simple alkylation reactions to give tri-, quadri-, quinque- and sexi-dentate derivatives. Simple alkylation by 2-picolinyl chloride provides the only example of a second reaction pathway where the azetidine ring of the reactant has undergone activation towards ring opening. Structural characterisation of the Cu(II) complexes of these ligands has revealed several remarkable aspects of their solid-state coordination chemistry, including the formation of infinite helical aggregates through pi-stacking and tetramerisation through carboxylate bridging, as well as further examples of the crystallisation of mixed species found to be rather common with complexes of the parent ligand.

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A relatively simple azetidine derivative with 2-aminoethyl and 2-pyridyl substituents functions as a tridentate ligand towards Cu(II), giving species in which the CuN3 unit is essentially planar and that, in the solid state, show a subtle balance between mononuclear and binuclear forms, allowing both to be simultaneously present in some lattices. Displacement of the ligand from Cu(II) by the use of cyanide results in the formation of cyanogen, which appears to slowly react with the free amine to give an oxamidine characterised in its doubly-deprotonated form as its binuclear Ni(II) complex.

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The structure of [CrF(2)([15]aneN(4))]ClO(4).H(2)O ([15]aneN(4)=1,4,8,12-tetraazacyclopentadecane) has been determined by a single-crystal X-ray diffraction study at 173 K. The complex crystallizes in the space group P1- of the triclinic system with two mononuclear formula units in a cell of dimensions a=9.

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In the title compound, [Cr(ONO)(2)(cyclam)]NO(2) (cyclam is 1,4,8,11-tetraazacyclotetradecane, C(10)H(24)N(2)), the complex cation is located on a twofold symmetry axis. The central Cr atom has a distorted octahedral coordination, involving two Cr-O bonds, with the monodentate nitrite O atoms adopting a cis configuration, and four Cr-N bonds. The mean Cr-N and Cr-O distances are 2.

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