Asymmetric Boron-Cored Aggregation-Induced Emission Luminogen with Multiple Functions Synthesized through Stepwise Conversion from a Symmetric Ligand

Abstract

Multifunction luminogens have emerged as promising candidates in high-performance sensor and imaging systems. Concise approaches to the synthesis of such molecules are urgently required both for fundamental research and technological applications. In this study, a new symmetric ligand of di(2-hydroxyphenyl)phthalazine with multiple binding sites around a phthalazine unit was readily synthesized, which could be converted efficiently into an asymmetric luminogen (OBN-DHPP) through the formation of oxygen−boron−nitrogen bonding. This molecule has a twistable π-extended backbone with a tetracoordinated boron core bearing two bulky phenyl groups, giving it abundant optical properties including a large Stokes shift piezochromism and aggregationinduced emission enhancement. Importantly, the presence of a free phenolic hydroxyl group in the backbone of OBN-DHPP enables the incorporation of various functional moieties into the asymmetric luminogen. As an example, polyethylene glycol (PEG)-modified luminogen (OBN-DHPP-PEG 45 ) was synthesized. In the aqueous medium, OBN-DHPP-PEG 45 could self-assemble into spherical nanoparticles with low cytotoxicity and excellent emission performance as well as high solubility. The results of flow cytometry and fluorescence microscopy reveal that these nanoparticles could be internalized successfully by HeLa cells, demonstrating their potential application in bioimaging.

Recent Advances in the Synthesis of Borinic Acid Derivatives

“…Because of this particular mechanism, most of the examples describe the use of triarylboranes bearing three identical aryl groups in order to prevent any mixture of different diarylborinates. As shown in Scheme 52 , a large variety of ligands on the organoborinates have been employed and can be sorted into three main categories: N,O -ligands [ 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 ], N , N -ligands [ 110 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 ...…”

Organolithium-Mediated Postfunctionalization of Thiazolo[3,2-c][1,3,5,2]oxadiazaborinine Fluorescent Dyes

“…N,O-coordinating organoboron dyes are currently intensively investigated because of their light-emissive properties. − They have been successfully used as emitters in organic light-emitting diodes and organic solid-state lasers . Other N,O-coordinating organoboron dyes exhibit aggregation-induced emission properties and have found applications in biological imaging .…”

“…N,O-coordinating organoboron dyes are currently intensively investigated because of their light-emissive properties. − They have been successfully used as emitters in organic light-emitting diodes and organic solid-state lasers . Other N,O-coordinating organoboron dyes exhibit aggregation-induced emission properties and have found applications in biological imaging . Classical synthesis of organoboron complexes is based on the preparation of the corresponding ligands and following complexation with boron-containing agents, such as BF 3 ·OEt 2 , BAlk 3 , BAr 3 , Ar 2 BOH, Ar 2 BOAlk, Ar 2 BCl, etc .…”