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BOIMPY: Fluorescent Boron Complexes with Tunable and Environment‐Responsive Light‐Emitting Properties
Author(s) -
Lee Boran,
Park Byung Gyu,
Cho Wansang,
Lee Ho Yong,
Olasz András,
Chen ChunHsing,
Park Seung Bum,
Lee Dongwhan
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201603837
Subject(s) - fluorescence , bodipy , molecule , boron , chemistry , photochemistry , protonation , chromophore , excited state , structural motif , organic chemistry , ion , biochemistry , physics , quantum mechanics , nuclear physics
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.