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The syntheses, structures and N2 adsorption properties of six new supramolecular metallacycles are reported. The metallacycles stack to form porous structures in the crystalline state and a guest exchange study with nitromethane and toluene reveals that the nanopore in [(dppp)-Pt]2(OTf)4 is a flexible property which was transferred from the linker to the supramolecular structure in the solid state.

An alkyne-azide addition, also known as click, reaction in conjunction with an electrostatic self-assembly and covalent fixation (ESA-CF) process is used to construct a variety of unprecedented multicyclic polymer topologies. Three types of multicyclic topologies that are composed of repeating ring, alternating ring/linear, and alternating ring/star units are prepared from an azide group, two alkyne groups at the opposite positions/alkyne group, and two alkyne groups at the opposite positions/azide group.

The thermal stability of a self-assembled micelle is enhanced by a topology effect and linear poly(butyl acrylate)-block-poly(ethylene oxide)-block-poly(butyl acrylate) and the cyclized product are self-assembled to form flower-like micelles. The studies have shown that both micelles are spherical and despite no change in the chemical composition or structure of the micelle, the cloud point is elevated by more than 40 [degree] C through the linear-to-cyclic topological conversion of the polymer amphiphile.

The gold(I)-catalyzed cycloisomerization of 1,5-enynes and 1,4-allylallenes to tetracyclododecane and tetracyclotridecane derivatives is described. A gold(I)-stabilized carbenoid intermediate has undergone a formal [sp.sup.3] C-H insertion to generate the tetracyclic adduct.

The coordination-driven self-assembly of four different trigonal prisms from 3 equiv of one of four different tetrapyridyl star connectors and 6 equiv of a platinum linker dication in nitromethane is presented. The use of a conformationally chiral star connector leads to a conformationally chiral prism when connector arm ends attached to a vertex have a strongly correlated twist sense and chirality is communicated across polyhedral faces, edges, and vertices.

Selective formation and stabilization of a kinetically favored self-assembled conductive nanocoil for the realization of nanoscale solenoids is presented. It was seen that the polymerized graphite nanocoils so obtained are conductive when doped with I2 and attractive for realization of nanoscale solenoids.

The generation of a supramolecular dimeric rhomboid and a trimeric hexagon is described. A study of their dynamic equilibrium is presented to obtain their thermodynamic properties.

An innovative method is described for the preparation of radially diblock graphitic nanotubes, whose functionalities on the interior and exterior surfaces are different from one another. The basic rationale of this concept can be utilized in a general method for site-selective and shape-persistent functionalization of potentially labile self-assembled nano-objects.

This study demonstrates the comprehensive investigation on the reversible linear-cyclic topological conversion of hydrophilic and hydrophobic polymers with various molecular weights. The reactions were triggered by light or heat, which reversibly dimerize and cleave the anthryl or coumarinyl end groups of the telechelics. Poly(ethylene oxide) telechelics with anthryl end groups attached through electron-donating (Ant-O-PEO and Ant-CH2-PEO) and electron-withdrawing (Ant-CO2-PEO) linking groups were synthesized. While Ant-O-PEO and Ant-CH2-PEO decomposed upon photoirradiation at 365 nm, Ant-CO2-PEO efficiently cyclized through the photodimerization of the anthryl end groups both in water and in organic solvents shown by NMR, SEC, and MALDI-TOF MS. The lower the molecular weight, the faster the cyclization proceeded. When cyclized Ant-CO2-PEO was heated at 150 °C in bulk, the polymers quantitatively converted back into the original linear topology. Furthermore, repeatable linear-cyclic topological conversion was confirmed. The reversible topological conversion of hydrophobic poly(tetrahydrofuran) telechelics with anthryl end groups (Ant-PTHF) was also successful. In addition, poly(ethylene oxide) telechelics with coumarinyl end groups (Cou-PEO) were also cyclized by irradiation at 365 nm in water. However, the cyclization hardly occurred when performed in methanol likely due to the lack of sufficient hydrophobic interaction of the coumarinyl end groups. Cyclized Cou-PEO was irradiated at 254 nm to test for linearization, finding the linear product and cyclic precursor were likely photoequilibrated. [ABSTRACT FROM AUTHOR]

The article discusses the importance of cationic gold in chemistry in the U.S. It states that cationic gold complexes have emerged as powerful acids capable of promoting a diverse range of enyne cycloisomerization reactions. It is discussed that in these reactions, the gold catalyst not only serves to activate the alkyne toward nucleophilic addition, but also plays a role in stabilizing the cationic intermediates produced in the cyclization event.

An alkyne-azide addition, i.e., click, reaction in conjunction with an electrostatic self-assembly and covalent fixation (ESA-CF) process has been demonstrated to effectively construct a variety of unprecedented multicyclic polymer topologies. A series of single cyclic poly(tetrahydrofuran), poly(THF), precursors having an alkyne group (Ia), an azide group (Ib), two alkyne groups at the opposite positions (IC), and an alkyne group and an azide group at the opposite positions (Id) have been prepared by the ESA-CF process. Moreover, a bicyclic 8-shaped precursor having two alkyne groups at the opposite positions (le) was synthesized. The subsequent click reaction of la with linear (ha) and three-armed star (llb) telechelic precursors having azide groups has been performed to construct bridged-type two-way (lla) and three-way (llb) paddle-shaped polymer topologies, respectively. Likewise, spiro-type tandem tricyclic (IVa) and tetracyclic (IVb) topologies resulted from lb/lc and lb/le, respectively. Furthermore, three types of multicyclic topologies that are composed of repeating ring (Va), alternating ringllinear (Vb), and alternating ring/star (Vc) units have been synthesized from ld, lc/lla, and lc/llb, respectively. [ABSTRACT FROM AUTHOR]

A triply fused tetracyclic macromolecular K(3,3) graph has been constructed through electrostatic self-assembly of a uniformly sized dendritic polymer precursor having six cyclic ammonium salt end groups carrying two units of a trifunctional carboxylate counteranions, and subsequent covalent conversion by the ring-opening reaction of cyclic ammonium salt groups at an elevated temperature under dilution. The K(3,3) graph product was isolated from the two constitutional isomers by means of a recycling SEC technique, as the hydrodynamic volume of the triply fused tetracyclic K(3,3) product is remarkably contracted in comparison with another isomer having a ladder form in solution.