title: BOIMPY: Fluorescent Boron Complexes with Tunable and Environment-Responsive Light-Emitting Properties.
abstract: A series of air-stable boron complexes 1-5 were prepared by using N-aryl iminopyrrolide ligands. Designed as minimalist structural mimics of the privileged BODIPY motif, these new BOIMPY (BOron complexes of IMinoPYrrolide ligands) fluorophores feature low molecular symmetry that promotes emission from CT-type excited states with large Stokes shifts and little self-quenching. Through comparative studies on the homologous set of compounds 1-4, we have confirmed that a delicate interplay between conformational twisting and donor-acceptor interaction dictates the mechanism of de-excitation, which responds sensitively to solvent polarity as well as protonation states. Over a wide visible spectral range, the structure-dependent light-emitting properties of BOIMPY molecules are well manifested, even in the solid-state. In order to exploit the environment-sensitive nature of CT-type emission, the BOIMPY motif was elaborated further into a bioprobe molecule 5. Live-cell fluorescence imaging studies have established that 5 is localized exclusively at lipid droplets to produce well-resolved staining patterns without affecting cell viability. These findings promise future elaboration of BOIMPY-based functional molecules for applications in biological imaging, chemical sensing, and molecular switching.
authors.affiliation: Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Boran
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA.
authors.forename: Byung Gyu
authors.initials: BG
authors.lastname: Park
authors.affiliation: Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Wansang
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA.
authors.forename: Ho Yong
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA.
authors.forename: András
authors.initials: A
authors.lastname: Olasz
authors.affiliation: Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA.
authors.forename: Chun-Hsing
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Seung Bum
authors.initials: SB
authors.lastname: Park
authors.affiliation: Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Dongwhan
authors.initials: D
authors.lastname: Lee
keywords: boron; chelates; conjugation; fluorescent probes; imaging agents