We demonstrate supramolecular pathway selection of a perylenediimide derivative in aqueous solution using chemically fueled redox reactions to control assembly/disassembly cycles. The number and frequency of cycles affect the nucleation and growth process, providing control over the size and internal order of the resulting self-assembled structures.

A series of multifunctional (mercaptomethyl)silanes of the general formula type R(n)Si(CH(2)SH)(4-n) (n = 0-2; R = organyl) was synthesized, starting from the corresponding (chloromethyl)silanes. They were used as multidentate ligands for the conversion of dodecacarbonyltriiron, Fe(3)(CO)(12), into iron carbonyl complexes in which the deprotonated (mercaptomethyl)silanes act as μ-bridging ligands. These complexes can be regarded as models for the [FeFe] hydrogenase. They were characterized by elemental analyses (C, H, S), NMR spectroscopic studies ((1)H, (13)C, (29)Si), and single-crystal X-ray diffraction. Their electrochemical properties were investigated by cyclic voltammetry to disclose a new mechanism for the formation of dihydrogen catalyzed by these compounds, whereby one sulfur atom was protonated in the catalytic cycle. The reaction of the tridentate ligand MeSi(CH(2)SH)(3) with Fe(3)(CO)(12) yielded a tetranuclear cluster compound. A detailed investigation by X-ray diffraction, electrochemical, Raman, Mössbauer, and susceptibility techniques indicates that for this compound initially [Fe(2){μ-MeSi(CH(2)S)(2)CH(2)SH}(CO)(6)] is formed. This dinuclear complex, however, is slowly transformed into the tetranuclear species [Fe(4){μ-MeSi(CH(2)S)(3)}(2)(CO)(8)].

Solid walls become increasingly important when miniaturizing fluidic circuitry to the micron scale or smaller. 1 They limit achievable flow-rates due to friction and high pressure drop, and are plagued by fouling 2 . Approaches to reduce the wall interactions have been explored using hydrophobic coatings 3,4 , liquid-infused porous surfaces [4][5][6] , nanoparticle surfactant jamming 7 , changing the surface electronic structure 8 , electrowetting 9,10 , surface tension pinning 11,12 , and atomically flat channels 13 . An interesting idea is to avoid the solid walls altogether. Droplet microfluidics achieves this, but requires continuous flow of both the liquid transported inside the droplets and the outer carrier liquid 14 . We demonstrate a new approach, where wall-less aqueous liquid channels are stabilised by a quadrupolar magnetic field that acts on a surrounding immiscible magnetic liquid. This creates self-healing, uncloggable, and near-frictionless liquidin-liquid microfluidic channels that can be deformed and even closed in real time without ever touching a solid wall. Basic fluidic operations including valving, mixing, and 'magnetostaltic' pumping can be achieved by moving permanent magnets having no physical contact with the channel. This wall-less approach is compatible with conventional microfluidics, while opening unique prospects for implementing nanofluidics without excessively high pressures.Magnetic forces have been used to avoid contact with the walls of a device by levitation of particles or live cells in suspension 15 , and a first attempt to make wall-less microfluidic channels resulted in continuous 'magnetic antitubes' of water surrounded by an aqueous paramagnetic salt solution 16 using

No abstract