Unprecedented J-Aggregated Dyes in Pure Organic Solvents

We describe the design and synthesis of the first organic dyes enabling spontaneous formation of stable J-aggregates in common organic solvents without additives. The new dyes are O-BODIPYs with a B-spiranic 4,4-diacyloxyl substitution pattern. Key to the effectiveness of the J-aggregation process is the high conformational rigidity of the Bspiranic molecular design as well as the orthogonal disposition of the B-diacyloxyl substituent and the meso-aryl group with respect to the mean plane of the borodiazaindacene. Atomistic simulations, both in vacuum and in a solvent cage, support the dynamics of the J-aggregation process as well as its dependence on the alkylation pattern of the BODIPY chromophore. A detailed analysis of the photophysical and laser properties of the new dyes provides convincing evidence for the unambiguous assignment of these J-aggregates and their dependence on the environmental conditions.We gratefully acknowledge financial support by the Spanish Ministerio de Economia y Competitividad (projects MAT2014-51937-C3-1-P, MAT2014- 51937-C3-2-P, MAT2014-51937-C3-3-P, and MAT2015-68837-REDT). I. E. thanks the Gobierno Vasco (IT339-10) for a predoctoral contract. H. M. acknowledges the Spanish Ministerio de Economia y Competitividad for a Juan de la Cierva postdoctoral contract. The authors thank SGIker of UPV/EHU for technical and human support with the X-ray diffraction measurements and computational calculations, which were carried out in the “arina” informatic cluster. We also thank Diego Plaza Lozano for preliminary synthetic studies.Peer reviewe