SUPPORTING INFORMATION A Water-soluble perylene dye functionalized with a 17β- estradiol: A new fluorescent tool for steroid hormones. Francisco J. Céspedes-Guirao, † Ana Belén Ropero, ‡ Enrique Font-Sanchis, † Ángel Nadal,* ,‡ Fernando Fernández-Lázaro,* ,† and Ángela Sastre-Santos* ,† División de Química Orgánica and Unidad de Fisiología Celular y Nutrición, Instituto de Bioingeniería, Universidad Miguel Hernández, Elche 03202, Spain CONTENTS (1) Materials and methods for the synthesis of 1 and 2 ............................. S2 (2) Synthesis of 1 ....................................................................................... S3 (3) Synthesis of 2 ....................................................................................... S9 (4) 1 H-, 13 (5) Figure 1. C-NMR and MS spectra of characterized compounds ............... S11 1 (6) Materials and methods for the biological experiments .......................... S28 H-NMR Monitoring to check tetramethylation, deprotection and anion exchange reactions yielding 1 .......................................................... S27 (7) References S29 Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2011