Wonbo Sim

A Calix‐bis‐crown with Hard and Soft Crown Cavities: Heterobinuclear K+/Ag+ Complexation in Solid and Solution States

Calixcrowns offer particular utility since the fusion of calixarene and crown ether units enables the divergent orientation of cavities of a size and nature sufficient to accommodate a variety of guests. Among them, calix[4]-bis-crowns with a 1,3-alternate conformation (or saddle-type) have interesting features including 1) two crown cavities able to undergo dinucleation and 2) HSAB-based complexation selectivity. Kim et al. reported the synthesis of a heterodinuclear complex of an unsymmetrical calix-bis-crown with two different size crown loops: a crown-5 and a crown-6 suitable for K and Cs , respectively. We recently reported the examples of calix[4]-bis-dithiacrown based, endo-coordinated disilver(I) complexes as well as an exo-coordinated 3D network connected by CuI-based clusters. Despite the existence of systems exhibiting 1) and 2) above, neither the preparation nor the crystal structure of any calixcrowns, which are designed to accommodate hard and soft metal ions in their individual cavities, has been reported previously. In view of this, we have focused our attention to the synthesis and characterization on a new calixbis-crown system designed to bind both soft and hard metal ions within its respective cavities. In preliminary work, we synthesized an unsymmetrical calix[4]-bis-crown, in which oxaand thiaoxa-crown rings are simultaneously bound to the calixarene scaffold. However, in this case the synthesized species with monothiaoxaand dithiaoxa-crown as the softer rings failed to accommodate Ag probably a result of K–Ag repulsion rather than a lack of complexation affinity for Ag . These results motivated us to optimize the ligand structure for this ion through the modification of the thiaoxa-crown unit and prepared the unsymmetrical calix[4]arene (4) incorporating O5/ O2S3-bis-crown rings ACHTUNGTRENNUNG(Scheme 1). To the best of our knowl-

Unsymmetrical Calixcrowns Incorporating Hard and Soft Loops as a New Scaffold for Multinuclear Endo/Exocyclic Complexation and Networking

Unsymmerical calix[4]crowns containing [(O(4)S)(O(5))] (L(1)) and [(O(4)S(2))(O(5))] (L(2)) as crown loops were employed as new scaffolds both for complexation studies and for network formation. Reactions of L(1) and L(2) with KI in the presence of CuI afforded a copper(I) iodide cluster linked 1D-type endocyclic dipotassium(I) complex [K(2)(L(1))(Cu(7)I(9))](n) (1) and a copper(I) iodide cluster linked 1D-type endocyclic monopotassium(I) complex [KL(2)(mu(2)-Cu(3)I(4))](n) (2), respectively. By comparison, the reaction of L(2) with KPF(6) in the presence of CuI and HgI(2) afforded the 1-D endocyclic potassium(I) complex [K(L(2))(CuHgI(4))](n) (3), linked with a CuHgI(4) cluster unit. The formation of homo- and heterodinuclear complexes in solution was also confirmed by comparative NMR studies.

Calix[4]arenes bridged with two different crown ether loops: Influence of crown size on metal ion recognition

A series of calix[4]arene-bis-crownethers were synthesized in a fixed 1,3-alternateconformation with good yields by the reaction of amonocyclic calixcrown ether with multi-ethyleneglycoldi-p-toluenesulfonate in the presence of cesiumcarbonate. In the preparation of the monocycliccalixcrown ethers (1 and 2), the use ofpotassium carbonate as a base provided the best yieldregardless of the template concept. In two phaseextraction and competitive transport experiments forligand-metal complexation, calix[4]arene biscrown(5) provided the best selectivity for potassiumion. When a calixbiscrown ether (4) bearingdifferent sized crown ether loops coordinates to K+and Cs+, respectively, the changes of peak splittingpatterns and chemical shift on 1H NMR spectra aredependent on the complexed metal ion species.

Isolation and identification of chondroitin sulfates from the mud snail

Chondroitin sulfates were isolated from the mud snail. For the quantitative analysis of enzymatic digestion products of isolated chondroitin sulfates, strong anion exchange-high performance liquid chromatography (SAX-HPLC) was performed. By the action of chondroitinase ABC, three unsaturated disaccharides 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-D-galactose (ΔDi-OS), 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (ΔDi-6S) and 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (ΔDi-4S) were produced from the mud snail chondroitin sulfates. The analysis showed that relative proportion of ΔDi-OS/ΔDi-6S/ΔDi-4S was 58.7/3.1/38.2. The immunomodulating activity of chondroitin sulfate was examined by cell proliferation assay and these results suggest that it might be a immunosuppressant.

6,7-Bis(bromo­meth­yl)-2,11,18,21,24,27-hexa­oxatetra­cyclo­[26.4.0.04,9.012,17]dotriaconta-1(28),4,6,8,12(17),13,15,29,31-nona­ene dichloro­methane monosolvate

The title 20-crown-6 unit, C28H30Br2O6·CH2Cl2, consisting of three benzo groups and triethylene glycol was prepared from the reaction of 1,2,4,5-tetrakis(bromomethyl)benzene and bisphenol in the presence of sodium hydride. In the crystal, one O atom of the central ethylene glycol in the triethylene glycol unit exhibits an exo conformation as a result of intramolecular C—H⋯O hydrogen bonds. The crown unit and the solvent molecule are linked by weak C—H⋯O hydrogen bonds.

2,9,16,19,22,25-Hexaoxatetra­cyclo­[24.4.0.24,7.010,15]dotriaconta-1(26),4,6,10(15),11,13,27,29,31-nona­ene

The title 22-crown-6 unit, C26H28O6, comprising of three benzo groups and triethylene glycol, was prepared by the reaction of α,α′-dibromo-p-xylene with 1,8-bis(2-hydroxyphenoxy)-3,6-dioxaoctane in the presence of Cs2CO3 with tetrahydrofuran (THF) and recrystallized from dichloromethane–hexane (1:20 v/v) at room temperature. In the molecular structure, two O atoms of the central ethylene glycol in the triethylene glycol unit exhibit exo conformations due to intramolecular C—H⋯O interactions. A number of C—H⋯O and C—H⋯π intermolecular interactions contribute to the stabilization of the crystal packing.

2,8,15,18,21,24,31,37,44,47,50,53-Dodeca-oxahepta-cyclo-[52.4.0.0(4,35).0(6,33).0(9,14).0(25,30).0(38,43)]octa-penta-conta-1(54),4,6(33),9(14),10,12,25(30),26,28,34,38(43),39,41,55,57-penta-deca-ene di-chloro-methane disolvate.

In the title compound, C46H50O12·2CH2Cl2, each dual 20-crown-6 unit crystallizes with two dichloromethane solvent molecules. The crown unit molecule lies about an inversion centre located at the central benzene ring. The two crown ring groups adopt an anti conformation, stabilized by weak intramolecular C—H⋯O interactions. In the crystal, the crown unit molecules and the solvent molecules are linked by C—H⋯O interactions into a three-dimensional network.

9-[3-(Carbazol-9-yl)-5-methyl-phen-yl]carbazole.

The title compound, C31H22N2, crystallizes with two symmetry-independent molecules in the asymmetric unit. The molecules have slightly different conformations, the dihedral angles between the central phenyl ring and the carbazolyl groups being 56.29 (4) and 59.57 (4)° in one molecule and 48.71 (4) and 65.47 (4)° in the other. In the crystal, molecules are linked by weak C—H⋯π and π–π [centroid–centroid distances = 3.7698 (10), 3.8292 (9), 3.9429 (10) and 3.9431 (10) Å].

2,9,12,15,18,25,27,34,37,40,43,50-Dodeca­oxa-56-aza­hepta­cyclo­[24.24.5.151,55.03,8.019,24.028,33.044,49]hexa­penta­conta-3,5,7,19(24),20,22,28(33),29,31,44,46,48,51,53,55-penta­deca­ene

The title compound, C43H45NO12, was prepared from the reaction of 2,6-bis(dibromomethyl)pyridine and bisphenol in the presence of caesium carbonate as a base. The central ring makes dihedral angles of 64.83 (6), 13.48 (6), 56.96 (6) and 66.21 (6)° with the peripheral rings. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯π interactions, forming a folded structure.

Picolyl-armed 1,3-alternate calix[4]areneazacrown ethers

A series of novel 1,3-alternate calix[4]arene-azacrown ethers with 2-picolyl, 3-picolyl, and benzyl groups on the nitrogen atom were synthesized by reaction of 1,3-alternate calix[4]arene-azacrown ether and aryl halide in the presence of triethylamine as base. Based on two-phase extraction, bulk liquid membrane, 1H NMR, and solid-state studies on this ligand–metal complexation, 2-picolyl-armed calixazacrown ether showed the highest selectivity for silver ion due to electrostatic interaction through effective three-dimensional encapsulation assisted by the nitrogen atom of the 2-picolyl group. p