Controlled Knoevenagel reactions of methyl groups of 1,3,5,7-tetramethyl BODIPY dyes for unique BODIPY dyes

Abstract

Formyl groups at 6-and 2,6-positions initiated Knoevenagel reactions of the methyl groups at the 7, and 1,7-positions of 1,3,5,7-tetramethyl BODIPY dyes with aromatic aldehydes. Formation of vinyl bonds at the 7-, and 1,7-positions facilitates further Knoevenagel reactions of the methyl groups at the 3,5positions. This approach offers fast, facile and versatile ways to prepare potential novel building blocks of BODIPY dyes for conjugated oligomers, dendrimers, and highly water-soluble, near-infrared emissive sensing materials.

Unusual Fluorescent Responses of Morpholine-Functionalized Fluorescent Probes to pH via Manipulation of BODIPY’s HOMO and LUMO Energy Orbitals for Intracellular pH Detection

“…Fluorescent probe A was prepared by replacing fluorine atoms of BOIDPY dye 1 at 4,4’-positions with 4-prop-2-ynyl-morpholine ( 2 ) (BODIPY dye 1 was synthesized according our reported procedures 17 via a Grignard reaction. In order to incorporate morpholine moieties onto 2,6-positions of BODIPY core, formyl groups were introduced to the BODIPY dye 3 (it was also synthesized according to our reported procedures) 18-19 at 2,6-positions via two-step Vilsmeier-Haack reactions, affording 2,6-diformyl BODIPY dye 4 . Then a reductive amination of BODIPY dye 4 with morpholine was carried out by using sodium acetoxyborohydride to yield fluorescent probe B .…”

Structural modification strategies for the rational design of red/NIR region BODIPYs

“…138 It is interesting to note that when electron withdrawing formyl groups are introduced at the 2,6positions, Knoevenagel reactions can only be initiated at the 7-or 1,7-positions. 141 20−30 nm shift is observed for each 1,7-position substituent. 141 The meso-(thiophen-2-yl)quinoline appended BODIPY 83 has an absorption maximum at 708 nm that does not shift when the solvent polarity is increased.…”

Synthesis and Theoretical Calculation of p-Aminostyryl-BODIPY Derivative: Trans-Configuration Selectivity of Knoevenagel Condensation Reaction

“…Modification of the BODIPY structure with electron-donating or withdrawing groups can change the fluorescence characteristic of BODIPY to the desired direction (Kolemen et al, 2011;Loudet & Burgess, 2007). The bathochromic shift to the longer wavelength is generally explored the point of the BODIPY core and improve the efficiency of some applications such as PDT (Zhu et al, 2012). Extension of the conjugation on the BODIPY core, bathochromically shifts absorption and fluorescence emission bands.…”