Supramolecular macrocycles reversibly assembled by Te ⋯ O chalcogen bonding

Organic molecules with heavy main-group elements frequently form supramolecular links to electron-rich centres. One particular case of such interactions is halogen bonding. Most studies of this phenomenon have been concerned with either dimers or infinitely extended structures (polymers and lattices) but well-defined cyclic structures remain elusive. Here we present oligomeric aggregates of heterocycles that are linked by chalcogen-centered interactions and behave as genuine macrocyclic species. The molecules of 3-methyl-5-phenyl-1,2-tellurazole 2-oxide assemble a variety of supramolecular aggregates that includes cyclic tetramers and hexamers, as well as a helical polymer. In all these aggregates, the building blocks are connected by Te(…)O-N bridges. Nuclear magnetic resonance spectroscopic experiments demonstrate that the two types of annular aggregates are persistent in solution. These self-assembled structures form coordination complexes with transition-metal ions, act as fullerene receptors and host small molecules in a crystal

Roadmap on holography

From its inception holography has proven an extremely productive and attractive area of research. While specific technical applications give rise to 'hot topics', and three-dimensional (3D) visualisation comes in and out of fashion, the core principals involved continue to lead to exciting innovations in a wide range of areas. We humbly submit that it is impossible, in any journal document of this type, to fully reflect current and potential activity; however, our valiant contributors have produced a series of documents that go no small way to neatly capture progress across a wide range of core activities. As editors we have attempted to spread our net wide in order to illustrate the breadth of international activity. In relation to this we believe we have been at least partially successful.This work was supported by Ministerio de Economía, Industria y Competitividad (Spain) under projects FIS2017-82919-R (MINECO/AEI/FEDER, UE) and FIS2015-66570-P (MINECO/FEDER), and by Generalitat Valenciana (Spain) under project PROMETEO II/2015/015

Reversibly Trapping Visible Laser Light through the Catalytic Photo-oxidation of I^– by Ru(bpy)₃²⁺

A Gaussian, visible laser beam traveling in a hydrogel doped with NaI and Ru­(bpy)₃Cl₂ spontaneously transforms into a localized, self-trapped beam, which propagates without diverging through the medium. The catalytic, laser-light-induced oxidation of I^– by [Ru­(bpy)₃]²⁺ generates I₃^– species, which create a refractive index increase along the beam path. The result is a cylindrical waveguide, which traps the optical field as bound modes and suppresses natural diffraction. When the beam is switched off, diffusion of I₃^– erases the waveguide within minutes and the system reverts to its original composition, enabling regeneration of the self-trapped beam. Our findings demonstrate reversible self-trapping for the first time in a precisely controllable, molecular-level photoreaction and could open routes to circuitry-free photonics devices powered by the interactions of switchable self-trapped beams

Reversibly Trapping Visible Laser Light through the Catalytic Photo-oxidation of I^– by Ru(bpy)₃²⁺

A Gaussian, visible laser beam traveling in a hydrogel doped with NaI and Ru­(bpy)₃Cl₂ spontaneously transforms into a localized, self-trapped beam, which propagates without diverging through the medium. The catalytic, laser-light-induced oxidation of I^– by [Ru­(bpy)₃]²⁺ generates I₃^– species, which create a refractive index increase along the beam path. The result is a cylindrical waveguide, which traps the optical field as bound modes and suppresses natural diffraction. When the beam is switched off, diffusion of I₃^– erases the waveguide within minutes and the system reverts to its original composition, enabling regeneration of the self-trapped beam. Our findings demonstrate reversible self-trapping for the first time in a precisely controllable, molecular-level photoreaction and could open routes to circuitry-free photonics devices powered by the interactions of switchable self-trapped beams

Reversibly Trapping Visible Laser Light through the Catalytic Photo-oxidation of I^– by Ru(bpy)₃²⁺

A Gaussian, visible laser beam traveling in a hydrogel doped with NaI and Ru­(bpy)₃Cl₂ spontaneously transforms into a localized, self-trapped beam, which propagates without diverging through the medium. The catalytic, laser-light-induced oxidation of I^– by [Ru­(bpy)₃]²⁺ generates I₃^– species, which create a refractive index increase along the beam path. The result is a cylindrical waveguide, which traps the optical field as bound modes and suppresses natural diffraction. When the beam is switched off, diffusion of I₃^– erases the waveguide within minutes and the system reverts to its original composition, enabling regeneration of the self-trapped beam. Our findings demonstrate reversible self-trapping for the first time in a precisely controllable, molecular-level photoreaction and could open routes to circuitry-free photonics devices powered by the interactions of switchable self-trapped beams