Effect of the iodine atom position on the phosphorescence of BODIPY derivatives: a combined computational and experimental study

A new BODIPY derivative ( o -I–BDP) containing an iodine atom in the ortho position of the meso -linked phenyl group was prepared. Photophysical and electrochemical properties of the molecule were compared to previously reported iodo BODIPY derivatives, as well as to the non-iodinated analog. While in the case of derivatives featuring iodine substituents in the BODIPY core, efficient population of the triplet state is accompanied by a substantial positive shift of the reduction potential compared to pristine BODIPY, o -I–BDP displays phosphorescence and simultaneously maintains the electrochemical properties of unsubstituted BODIPYs. A theoretical investigation was settled to analyze results and rationalize the influence of iodine position on electronic and photophysical properties, with the purpose of preparing a fully organic phosphorescent BODIPY derivative. TD-DFT and spin–orbit coupling calculations shed light on the subtle effects played by the introduction of iodine atom in different positions of BODIPY. Graphical abstract