Université de Fribourg

Tripodal osmium polypyridyl complexes for self-assembly on platinum nanoparticles

Contreras-Carballada, Pablo ; Edafe, Fabio ; Tichelaar, Frans D. ; Belser, Peter ; Cola, Luisa De ; Williams, René M.

In: The Journal of Physical Chemistry Letters, 2011, vol. 2, no. 12, p. 1460–1463

The combination of platinum nanoparticles with a tripodal osmium complex that anchors to the metal surface leads, under visible light irradiation, to the formation of solvated electrons. The formation kinetics is limited by the detachment of the electron from the platinum surface into the solution, the particle showing a type of capacitor behavior

Université de Fribourg

Luminescent acetylthiol derivative tripodal osmium(II) and iridium(III) complexes: Spectroscopy in solution and on surfaces

Ramachandra, Srinidhi ; Polo, Federico ; Edafe, Fabio ; Schuermann, Klaus C. ; Nijhuis, Christian A. ; Belser, Peter ; Reus, William F. ; Whitesides, George M. ; Cola, Luisa De

In: Pure and Applied Chemistry, 2011, vol. 4, no. 83, p. 779-799

Luminescent Os(II) and Ir(III) complexes containing a tripodal-type structure terminalized with three thiol derivatives are described. The tripod is introduced through derivatization, with a rigid spacer, of a phenanthroline ligand coordinated to the metal ion, and the entire structure possesses axial geometry. The geometry of the complexes combined with the three anchoring sites, the thiol...

Université de Fribourg

On the reversible photoisomerization of spiropyran-modified zeolite L single crystals

Albuquerque, R. Q. ; Kühni, Joël ; Belser, Peter ; Cola, Luisa De

In: ChemPhysChem, 2010, vol. 11, no. 3, p. 575-578

The reversible photoisomerization of a derivative of spiropyran at the level of a single crystal by using zeolite L is demonstrated. The synthesized spiropyran exhibits rare negative photochromism when dissolved in a 1:1 mixture of H₂O and EtOH The spiropyran is functionalized predominantly at the channel entrances in the case of 4 μm long crystals

Université de Fribourg

Photophysical and redox properties of dinuclear ru and os polypyridyl complexes with incorporated photostable spiropyran bridge

Jukes, Ron T. F. ; Bozic, Biljana ; Belser, Peter ; Cola, Luisa De ; Hartl, František

In: Inorganic Chemistry, 2009, vol. 48, no. 4, p. 1711–1721

Aimed at creating a true photoswitchable energy transfer system, four dinuclear complexes containing ruthenium(II) and osmium(II) metal centers bridged by spiropyran-type linkers were designed and investigated. The bridge in its closed spiropyran form was shown to be a good insulator for energy transfer between the Ru-bpy donor and the Os-bpy acceptor (bpy = 2,2′-bipyridine). On the basis of...

Université de Fribourg

Photochemical, photophysical and redox properties of novel fulgimide derivatives with attached 2,2′-bipyridine (bpy) and [M(bpy)₃]²⁺ (M = Ru and Os) moieties

Jukes, Ron T. F. ; Kühni, Joël ; Salluce, Nunzio ; Belser, Peter ; Cola, Luisa De ; Hartl, František

In: Dalton Transactions, 2009, p. 3993-4002

Fulgimides monosubstituted with [M(bpy)₃]²⁺ (M = Ru, Os; bpy = 2,2′-bipyridine) chromophore units and with a single bpy group were synthesized and investigated as components of conceivable dinuclear photochromic switches of luminescence. The E-, Z- and closed-ring (C) photoisomer forms of the bpy-bound fulgimide were successfully separated by semi-preparative HPLC. The same...

Université de Fribourg

Photochromic switches incorporated in bridging ligands: a new tool to modulate energy-transfer

Belser, Peter ; Cola, Luisa De ; Hartl, F. ; Adamo, Vincenzo ; Bozic, Biljana ; Chriqui, Yoel ; Iyer, Vijay Mahadevan ; Jukes, R. T. F. ; Kühni, Joel ; Querol, Manel ; Roma, Silvia ; Salluce, Nunzio

In: Advanced Functional Materials, 2006, vol. 16, no. 2, p. 195-208

The thoughful construction of molecular switches has led to a gamut of supramolecular systems that can be used in molecular electronics. These include molecules based on thienylethenes, spiropyrans, fulgides, dithienylphenanthrolines, and diazafluorenes. This article reviews the recent developments made in the synthesis and characterization of all these systems, thereby allowing a comparative...