Yeon Sil Park

Hydrazide as a New Hydrogen-Bonding Motif for Resorcin[4]arene-Based Molecular Capsules

The resorcin[4]arene-based benzoylhydrazide cavitands formed stable molecular capsules in nonpolar solvents by the eight intermolecular N-H...O=C hydrogen bondings, two from each four paired hydrazides, and the four intramolecular O-H2C-O...H-N hydrogen bondings on each cavitand. The stability of these molecular capsules depends on the encapsulated guest in the following order: CH3SO3(-) > CH3CO2(-) > CH3CH2NH2 x HCl approximately = CH3NH2 x HCl > (CH3)4N(+) > toluene > C2D2Cl4.

Isolation and characterization of the major colorant in Gardenia fruit

Abstract The major yellow colorant from the fruit of Gardenia jasminoides was isolated and then identified with the aid of FAB–MS, UV/visible and NMR data. The NMR assignments were based on data from 1H NMR, 13C NMR, DQF–COSY, NOESY, HMQC and HMBC measurements. Molar absorptivity was determined using an analytically pure sample of crocin.

Encapsulation of Anionic guests in a New Hydantoinylamido Molecular Capsule

Resorcin[4]arene-based tetrakis(N-hydantoinylamido)cavitand 1 forms a stable molecular capsule in the presence of suitable anionic guests such as CH(3)OSO(3)(-) or BF(4)(-) in C(2)D(2)Cl(4). Molecular capsule G(2)@1(2) is stabilized by the eight intermolecular imide N-H···O═C hydrogen bondings, two from each four paired hydantoinyl units, and the eight intramolecular amide N-H···O-CH(2)-O hydrogen bondings, four on each two cavitands. The formations of molecular capsules were confirmed by (1)H, 2D NOESY, and 2D-DOSY NMR.

New deep cavitand with imidazoquinoxaline flaps: formation of static helical alkane inclusion complexes by enhanced CH/π interactions

A new deep imidazoquinoxaline cavitand formed static helical alkane inclusion complexes by CH/pi stabilization of alkanes with the enlarged aromatic pi surfaces of the cavity inside.

Strongly basic macrocyclic triamines, 1,5,9-triazacyclododecanes for solvent extraction of gold(I) cyanide

Abstract Solvent extraction of gold(I) dicyanide anion from alkaline gold(I) cyanide solution using unusually basic amine extractants was conducted. 1,5,9-Triazacyclododecane ( 4 ) is known as an unusually basic macrocyclic amine having p K a =12.3–12.7, and is thus a good candidate as a basic amine extractant. Three lipophilic derivatives of 4 expected to stay in the organic phase during gold solvent extraction were synthesized. N -Dodecyl-1,5,9-triazacyclododecane ( 3 ) was prepared from 1,5,9-triazacyclododecane-2,4-dione ( 1 ) by N-alkylation with n -dodecyl iodide and then reduction with BH 3 -THF. N , N ′-Didodecyl-1,5,9-triazacyclododecane ( 5 ) and N , N ′, N ′′-tridodecyl-1,5,9-triazacyclododecane ( 6 ) were efficiently synthesized by selective di-alkylation of 4 with n -dodecyl iodide, and by reductive alkylation of 4 with n -dodecanal, respectively. The extractants 3 and 6 showed pH 50 =10.5, which is the minimum value required for practical application.

A Magnesium-Selective Ionophore Containing Four Amide Carbonyl Ligands Derived from L-Tartaric Acid and Axial Furano Oxygen Binding Sites

Octahedrally converging hexadentate macrocyclic receptors 1 and 2, based on L-tartaric acid and furanmoieties, were synthesized andtheir complexation properties studied. In this paper,magnesium ion selectivitiesdetermined by ISE experiments, chiroptical changes observedby circular dichroism(CD) on complexation, and association constants measuredby NMR titration arediscussed.