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Université de Fribourg

Assessment of theoretical prediction of the NMR shielding tensor of ¹⁹⁵PtClxBr6–x²⁻ complexes by DFT calculations: experimental and computational results

Penka Fowe, Emmanuel ; Belser, Peter ; Daul, Claude A. ; Chermette, Henry

In: Physical Chemistry Chemical Physics, 2005, vol. 7(8), p. 1732-1738

In the present work, the ZORA spin–orbit Hamiltonian, in conjunction with the gauge including orbital (GIAO) method based on DFT theory has been used to calculate ¹⁹⁵Pt chemical shift of ¹⁹⁵PtClxBr6–x²⁻ complexes. Excellent agreement with experiments has been obtained for calculations bearing on optimized geometries and all electrons triple zeta +...

Université de Fribourg

Efficient and robust host–guest antenna composite for light harvesting

Devaux, André ; Calzaferri, Gion ; Belser, Peter ; Cao, Pengpeng ; Brühwiler, Dominik ; Kunzmann, Andreas

In: Chemistry of Materials, 2014, vol. 26, no. 23, p. 6878–6885

We report discovery of a new efficient and robust antenna composite for light harvesting. The organic dye hostasol red (HR) is strongly luminescent in aprotic solvents but only weakly luminescent in potassium zeolite L (ZL) at ambient conditions. We observed a dramatic increase of the luminescence quantum yield of HR–ZL composites if some or all exchangeable potassium cations of ZL are...

Université de Fribourg

Gated photochromism of 1,2-diarylethenes

Kühni, Joël ; Belser, Peter

In: Organic Letters, 2007, vol. 9, no. 10, p. 1915 -1918

A dithienylethene derivative containing a cyclobutene-1,2-dione skeleton does not exhibit photochromic properties. However, when both ketone functions are protected with cyclic acetal groups, photochromic behavior is observed.

Université de Fribourg

Host–guest interactions and orientation of dyes in the one-dimensional channels of zeolite L

Fois, Ettore ; Tabacchi, Gloria ; Devaux, André ; Belser, Peter ; Brühwiler, Dominik ; Calzaferri, Gion

In: Langmuir, 2013, vol. 29, no. 29, p. 9188–9198

A combined experimental and modeling study of methylacridine (MeAcr⁺) dye-zeolite L composites unravels the microscopic origin of their functional properties. The anisotropic orientation of the cationic dye inside the ZL channel is unambiguously determined and understood. The most stable orientation of MeAcr⁺, which features both its long and short molecular axes nearly perpendicular to the...

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

A perfluorocyclopentene dithienylethene based molecular switch: 1,2-bis[5-(4-ethynylphenyl)-2-methylthiophen-3-yl]-3,3,4,4,5,5-hexafluorocyclopentene

Iyer, Vijay Mahadevan ; Stoeckli-Evans, Helen ; Belser, Peter

In: Acta Crystallographica E, 2006, vol. 62, no. 9, p. o3942-o3943

The title compound, C₃₁H₁₈F₆S₂, is a molecular switch based on dithienylperfluorocyclopentene. The molecule possesses pseudo-C₂ symmetry and has the open form of the switch. There are a number of intramolecular C-H...F hydrogen bonds, but in the crystal structure there are no interactions between symmetry-related molecules.

Université de Fribourg

Photochemical investigation of a photochromic diarylethene compound that can be used as a wide range actinometer

Ribeiro Santos, André ; Ballardini, Roberto ; Belser, Peter ; Gandolfi, Maria Teresa ; Mahadevan Iyer, Vijay ; Moggi, Luca

In: Photochemical & Photobiological Sciences, 2009, vol. 8, p. 1734-1742

The photochromic diarylethene derivative 1,2-bis(5-(4-ethynylphenyl)-2-methylthiophen-3-yl)perfluorocyclopentene (1) was submitted to photochemical, thermal stability and fatigue resistance studies in acetonitrile, also to evaluate its possible application as a new actinometer. This photochromic system covers a wide spectral absorption range, with intense bands in the UV and visible regions for...

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...