Introduction of Water-Solubilizing Groups at the Lower Rim of Tolylpyridine-Bridged Cavitands

In this paper the preparation of water-soluble methylene-bridged cavitands presenting either positively or negatively charged groups at the lower rim following three different synthetic routes is reported. Moreover, four anionic sulphate functions have been successfully inserted on a tolylpyridine-bridged cavitand in order to carry out the self-assembly of coordination cages in water.     

A Polymorphic Azobenzene Cage for Energy-Efficient and Highly Selective p-Xylene Separation

Developing the competence of molecular sorbents for energy-saving applications, such as C8 separations, requires efficient, stable, scalable, and easily recyclable materials that can readily transition to commercial implementation. Herein, we report an azobenzene-based cage for the selective separation of p-xylene isomer across a range of C8 isomers in both vapor and liquid states with selectivity that is higher than the reported all-organic sorbents. The crystal structure shows non-porous cages that are separated by p-xylene molecules through selective CH–π interactions between the azo bonds and the methyl hydrogen atoms of the xylene molecules. This cage is stable in solution and can be regenerated directly under vacuum to be used in multiple cycles. We envisage that this work will promote the investigation of the azo bond as well as guest-induced crystal-to-crystal phase transition in non-porous organic solids for energy-intensive separations.     

Macrocycle-Directed Construction of Tetrahedral Anion–π Receptors for Nesting Anions with Complementary Geometry

Manipulation of the emerging anion–π interactions in a highly cooperative manner through sophisticated host design represents a very challenging task. In this work, unprecedented tetrahedral anion–π receptors have been successfully constructed for complementary accommodation of tetrahedral and relevant anions. The synthesis was achieved by a macrocycle-directed approach by using large macrocycle precursors bearing four reactive sites, which enabled a kinetic-favored pathway and afforded the otherwise inaccessible tetrahedral cages in considerable yields. Crystal structure suggested that the tetrahedral cages have an enclosed three-dimensional cavity surrounded by four electron-deficient triazine faces in a tetrahedral array. The complementary accommodation of a series of tetrahedral and relevant anions including BF₄⁻, ClO₄⁻, H₂PO₄⁻, HSO₄⁻, SO₄²⁻ and PF₆⁻ was revealed by ESI-MS and DFT calculations. Crystal structures of ClO₄⁻ and PF₆⁻ complexes showed that the anion was nicely encapsulated within the tetrahedral cavity with up to quadruple cooperative anion–π interactions by an excellent shape and size match. The strong anion–π binding was further confirmed by negative ion photoelectron spectroscopy measurements.     

多孔有机笼毛细管电色谱手性柱的研究

该文以(1R,2R)-二苯乙二胺与2-羟基-1,3,5-均苯三甲醛合成出比表面积大、孔隙度均一、具有四面体结构的多孔有机笼(POC),采用X射线粉末衍射、核磁共振波谱、傅里叶变换红外光谱、热重分析、扫描电子显微镜和氮气吸附对制备的多孔材料进行表征.将该POC用作手性固定相制备毛细管电色谱柱,优化了电色谱的工作电压、缓冲...     

Small Synthetic Macrocyclic Cages. Proton Transfer Properties and Metal Complexes

Abstract

The synthesis, characterization and ligational properties of a series of small macrocyclic cages are discussed.     

Synthesis, structure and optical features of single adamantanoid Hg-SePh-X anionic clusters stabilized by octahedral complexes (Ph = phenyl; X = Cl, Br, I)

The ligand dppmo₂ [CH₂{P(O)Ph₂}₂] (Ph = phenyl), MgCl₂·6H₂O, MgBr₂, MgI₂, FeBr₂, CoBr₂, NiBr₂ and Hg(SePh)₂ react one at a time to give the complex salt of the general formula [M(dppmo₂)₃][Hg₄X₄(SePh)₆]·4dmf·H₂O (M = Mg²⁺, Fe²⁺, Co²⁺, Ni²⁺; X = Cl, Br, I; dmf = dimethylformamide). The cations [M(dppmo₂)₃]²⁺ are predominantly octahedral with axial angles from 175° to 178°. The adamantane like anions [Hg₄X₄(SePh)₆]²⁻ are examples of single adamantanoid species, since these compounds normally appear as polymers or fused cages. Adamantanoid cages are the preferential thermodynamic configuration for this atomic aggregate. They appear as single molecules or ions however only in a halogen rich reactions milieu.     

Self-assembly of a cavitand-based heteronuclear coordination cage

A new self-assembly protocol leading to the formation of heteronuclear coordination cage 10 is reported. Reaction of tetradentate cavitand ligand 1, bearing one ethynylpyridine and three benzonitriles at the apical positions, with Pt(dppp)OTf₂ and Pd(dppp)OTf₂ in a 1:3 ratio yields 10 as the thermodynamic product. Under the same conditions, the self-assembly of 1 with either Pt or Pd metal precursors gives a mixture of isomeric homonuclear cages 8a-c or 9a-c, respectively.