RESUMEN
A bipyridinium dication-substituted Bodipy fluorophore, with a terminal carboxylic acid function, provides two alternative stations for cucurbit[7]uril. Changing pH from basic to acidic results in shuttling of the cucurbit[7]uril from one station to another. In addition, this shuttling is accompanied by a change in the emissive properties of the Bodipy dye, which is only observed in the presence of cucurbit[7]uril. More striking, is a demonstration of autonomous shuttling of the pseudorotaxane system in an oscillating pH system.
RESUMEN
Multicomponent reactions between 1,4-benzenediboronic acid, catechol, and different pyridyl ligands are reported. The condensation of 1,4-benzenediboronic acid with catechol gives 1,4-bis(benzodioxaborole)benzene. Upon crystallization, the ester aggregates with the N-donor ligands through dative B-N bonds. Depending on the nature of the pyridyl ligand, molecularly defined macrocycles or polymeric structures are obtained. 1D polymers are formed with 4,4-bipyridine and 1,2-di(4-pyridyl)ethylene, whereas a 2D network is obtained with the tetradentate ligand tetra(4-pyridylphenyl)ethylene. These results highlight the utility of dative B-N bonds in structural supramolecular chemistry and crystal engineering.
RESUMEN
Dative boron-nitrogen bonds were found to be a useful binding motif in structural supramolecular chemistry. Crystalline cages were formed using a diboronate ester and 2,4,6-tri(4-pyridyl)-1,3,5-triazine. These cages can act as hosts for electron-rich planar aromatic systems such as triphenylene. Further, crystalline two-dimensional polymers were formed via dative B-N bonds between a triboronic ester and a ditopic pyridyl ligand. Use of an extended triboronate ester resulted in formation of a gel in toluene with a minimum gelation concentration of 0.5 wt%.
RESUMEN
The condensation of multiple building blocks in a ball mill allows molecular cages with a size up to 3.1 nm to be built.
RESUMEN
A novel distyryl-substituted boradiazaindacene (BODIPY) dye displays interesting properties as a sensitizer in DSSC systems, opening the way to further exploration of structure-efficiency correlation within this class of dyes.
RESUMEN
A new catalytic procedure for atom-transfer radical addition (ATRA) and cyclization (ATRC) reactions is described. The combination of the ruthenium(III) complex [RuCl(2)Cp*(PPh3)] (Cp*: pentamethylcyclopentadienyl) with magnesium allows these reactions to be performed under mild conditions with high efficiency. In most cases, the catalyst concentrations required are significantly lower than those used in previously reported procedures. It is suggested that magnesium acts as a reducing agent that generates and regenerates the catalytically active ruthenium(II) species. The precatalyst [RuCl(2)Cp*(PPh3)] has been analyzed by X-ray crystallography.
