Jungseok Heo

Selective Inclusion of a Hetero‐Guest Pair in a Molecular Host: Formation of Stable Charge‐Transfer Complexes in Cucurbit[8]uril

Two different molecules are selectively included in cucurbit[8]uril to form a stable 1:1:1 ternary complex, which has been characterized by X-ray crystallography. The inclusion of a hetero-guest pair (a pyridinium derivative (blue) and 2,6-dihydroxynaphthalene (magenta)) in the molecular host is driven and stabilized by a charge-transfer interaction between the electron-rich and electron-deficient guests.

A Two-Dimensional Polyrotaxane with Large Cavities and Channels: A Novel Approach to Metal–Organic Open-Frameworks by Using Supramolecular Building Blocks

A seven-membered molecular necklace composed of six copper ions and six pseudorotaxane units behaves as a secondary building block in the formation of a two-dimensional polyrotaxane network with large voids. This novel metal-organic framework allows size-selective anion exchange as well as the exchange of coordinated ligands. Thus a new synthetic strategy has been identified for modular porous solids which utilizes large, rigid, interlocked supermolecules as primary or secondary building blocks.

SHAPE-INDUCED, HEXAGONAL, OPEN FRAMEWORKS : RUBIDIUM ION COMPLEXED CUCURBITURIL

A honeycomb structure is shown by the one-dimensional coordination polymer comprising D6h -symmetric cucurbituril molecules and rubidium ions (see picture). The cucurbituril molecules stack atop one another and show coordination of their carbonyl groups to the rubidium ions in between. The shape and symmetry of the building blocks encourage the coordination polymer chains to be arranged in such a way as to produce an open-framework structure with large, linear, hexagonal channels.

Columnar one-dimensional coordination polymer formed with a metal ion and a host–guest complex as building blocks: potassium ion complexed cucurbituril

Abstract A novel one-dimensional coordination polymer comprising a metal ion and a host–guest complex is described. Cucurbituril, a barrel-shaped molecule and potassium ion form a columnar 1D coordination polymer in the solid state, formula of which is [(C 36 H 36 N 24 O 12 )K 2 (OH) 2 ·(C 4 H 8 O)] n . In the coordination polymer, cucurbituril molecules stack atop one another through coordination of their carbonyl groups to the potassium ions in between. A disordered THF molecule is encapsulated in the cavity of each of the cucurbituril molecule.

Eine molekulare Schüssel mit einem Metallion als Boden: reversibler Einschluß organischer Moleküle in Cs+‐komplexiertes Cucurbituril

Einfach durch Anderung des pH-Werts kann der Einschlus und die Freisetzung kleiner organischer Molekule in Cs+-komplexiertem Cucurbituril gesteuert werden, wie unten schematisch fur THF als Gastmolekul gezeigt.

Self-Assembly of Interlocked Structures and Open Framework Materials using Coordination Bonds

Abstract Syntheses of molecular necklaces and open framework materials using coordiantion bonds are described. In the synthesis of molecular necklaces, the barrel-shape molecule cucurbituril is used as a molecular “bead” and metal ions or metal complexes are used as “glue” or “angle connectors”. Two different approaches were taken. In one approach, linear pseudorotaxanes react with Pt(en)(NO3)2 (en = ethylenediamine) to produce [4]MNs and [5]MNs. In the other approach, a′ 2 + 2′ approach, preorganized, L-shaped pseudorotaxanes containing two molecular “beads” react with a metal ion (or a metal complex with cis vacant coordination sites) to form [5]MNs. Rubidium and cucurbituril form a one-dimensional coordination polymer in the solid state, in which cucurbituril molecules stack atop one another through coordination of their carbonyl groups to the rubidium ions in between. The coordination polymer chains are arranged in such a way as to produce a honeycomb structure with large linear hexagonal channels parallel to the polymer chains.

Self-Assembly of Interlocked Structures: Rotaxanes, Polyrotaxanes and Molecular Necklaces

Abstract Our recent work on construction of interlocked structures such as rotaxanes, polyrotaxanes and molecular necklaces using the principles of self assembly and coordination chemistry is described. In the synthesis of these structures, the barrel-shape molecule cucurbituril is used as a molecular “bead” and metal ions or metal complexes are used as “glue” or “angle connectors”. Judicious choice of metal ions, counter ions and “strings” is important in order to construct the desired supramolecular structures.

Selective Modulation of Charge‐Carrier Transport of a Photoanode in a Photoelectrochemical Cell by a Graphitized Fullerene Interfacial Layer

We show that a graphitic carbon interfacial layer, derived from C70 by annealing at 500 °C, results in a significant increase in the attainable photocurrent of a photoelectrochemical cell that contains a WO3 -functionalized fluorine-doped tin oxide (FTO) photoanode. Time-resolved photoluminescence spectroscopy, photoconductive atomic force microscopy, Hall measurements, and electrochemical impedance spectroscopy show that the increase in photocurrent is the result of fast and selective electron transport from optically excited WO3 through the graphitic carbon interfacial layer to the FTO-coated glass electrode. Thus the energy efficiency of perspective solar-to-fuel devices can be improved by modification of the interface of semiconductors and conducting substrate electrodes by using graphitized fullerene derivatives.

Co-ordination chemistry of CuI with 1,3,5-tris[bis(pyridin-2-ylmethyl)aminomethyl]-2,4,6-triethylbenzene, a conformationally constrained trinucleating ligand

The new ligand 1,3,5-tris[bis(pyridin-2-ylmethyl)aminomethyl]-2,4,6-triethylbenzene (L) was prepared from 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene (TriBr) and bis(pyridin-2-ylmethyl)amine. In the crystal state TriBr adopts a conformation with the substituents alternately pointing to opposite sides of the plane of the benzene ring. Compound L adopts a similar conformation. With its donor sets thus coming together on the same side of the benzene ring L can co-ordinate three copper(I) species in a defined and close proximity. This is illustrated by the crystal structures of L, [(CuI)3L] and [(CuNCMe)3L][PF6]3. The electrochemical interdependence of the copper centres in [(CuI)3L] and [(CuBr)3L] has been investigated by cyclic voltammetry. With weaker and harder terminal ligands such as acetonitrile the [CuI3L]3+ species in CH2Cl2 are liable to oxidation by the solvent to give CuIICl+ species. In one such degradation product L co-ordinates besides an isolated CuI, a CuI and a CuII bridged by a single chloride. The CuII is further co-ordinated by an oxygen from a perchlorate anion. From the reaction of only two equivalents of [Cu(NCMe)4]BF4 with L a dinuclear compound was obtained, in which both copper atoms experience a distorted trigonal co-ordination from three pyridine nitrogen atoms each.

CCDC 167484: Experimental Crystal Structure Determination

Related Article: Ki-Min Park, Dongmok Whang, Eunsung Lee, Jungseok Heo, Kimoon Kim|2002|Chem.-Eur.J.|8|498|doi:10.1002/1521-3765(20020118)8:2 3.3.CO;2-D