Solvent‐Driven Conformational Exchange for Amide‐Linked Bichromophoric BODIPY Derivatives |
| |
Authors: | Shrikant Thakare Patrycja Stachelek Dr Soumyaditya Mula Ankush B More Prof Subrata Chattopadhyay Prof Alok K Ray Prof Nagaiyan Sekar Dr Raymond Ziessel Prof Dr Anthony Harriman |
| |
Institution: | 1. Department of Dyestuff Technology, Institute of Chemical Technology, Mumbai, India;2. Molecular Photonics Laboratory, School of Chemistry, Newcastle University, Newcastle upon Tyne, UK;3. Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai, India;4. Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai, India;5. Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), Ecole Européenne de Chimie, Polymères et Matériaux, Université de Strasbourg, Strasbourg Cedex?02, France |
| |
Abstract: | The fluorescence lifetime and quantum yield are seen to depend in an unexpected manner on the nature of the solvent for a pair of tripartite molecules composed of two identical boron dipyrromethene (BODIPY) residues attached to a 1,10‐phenanthroline core. A key feature of these molecular architectures concerns the presence of an amide linkage that connects the BODIPY dye to the heterocyclic platform. The secondary amide derivative is more sensitive to environmental change than is the corresponding tertiary amide. In general, increasing solvent polarity, as measured by the static dielectric constant, above a critical threshold tends to reduce fluorescence but certain hydrogen bond accepting solvents exhibit anomolous behaviour. Fluorescence quenching is believed to arise from light‐induced charge transfer between the two BODIPY dyes, but thermodynamic arguments alone do not explain the experimental findings. Molecular modelling is used to argue that the conformation changes in strongly polar media in such a way as to facilitate improved rates of light‐induced charge transfer. These solvent‐induced changes, however, differ remarkably for the two types of amide. |
| |
Keywords: | BODIPY boron charge transfer conformational exchange dyes/pigments fluorescence isomerisation |
|
|