Phenylethynyl-BODIPY Oligomers: Bright Dyes and Fluorescent Building Blocks

Abstract

Boradiazaindacene dyes were converted into phenylethynyl-BODIPY oligomers via a cycle of reactions, notably including Sonogashira couplings. As expected, as the number, n, of repeating units increases, peak absorption and emission wavelengths are shifted to the red end of the visible spectrum, albeit with smaller increments as n increases. Decyl groups help to keep the solubility remarkably high, and in addition to being very bright red-emitting fluorophores, their rigid rod-like structures could allow their use as functional building blocks.As evidenced by the number of recent reviews, 1 there has been increased interest in the derivatization of BODIPY dyes 2 and their applications 3 in recent years. Part of this interest is focused on finding novel strategies 2a,b,e,4,5 to push the absorption and emission wavelengths further into the red. The parent dye is a green-emitting fluorophore, comparable to fluorescein; however, with structural modifications, the chromophore can be transformed into a red-to near-IRemitting dye.In this report, we disclose our attempts to shift the dye's working range of wavelengths into red, by extending the conjugation on the 2,6-axis through iterative Sonogashira couplings, yielding the first examples of oligomeric BODIPY dyes. The synthesis plan is shown in Scheme 1. From the very start, we realized that as the BODIPY chain is extended, solubility is likely to become an issue. † Middle East Technical University. ‡ Bilkent University.(1) Recent reviews on BODIPY dyes:(a) Ulrich, G.; Ziessel, R.; Harriman, A. Angew. Chem., Int. Ed. 2008, 47, 1184-1201 Ulrich, G.; Harriman, A. New J. Chem. 2007, 31, 496-501

Designing Excited States: Theory‐Guided Access to Efficient Photosensitizers for Photodynamic Action

“…Bodipy dyes are exceptional fluorophores with amazing versatility [11][12][13][14][15][16][17] and rich chemistry. [18][19][20][21][22][23][24] Heavy-atom-functionalized Bodipy dyes showed some promise as potential sensitizers for photodynamic activity. [25][26][27][28] It is also interesting to note that a few years ago, dimeric (albeit non-orthogonal) Bodipy derivatives with peculiar properties linked to exciton coupling between the chromophores were reported.…”

One-pot efficient synthesis of dimeric, trimeric, and tetrameric BODIPY dyes for panchromatic absorption

“…[2][3][4][5][6] Polymeric BODIPY dyes have been shown to have promising applications in solar cells. [2][3][4]8 These tedious procedures limit practical use of these new BODIPY dyes. [2][3][4]8 These tedious procedures limit practical use of these new BODIPY dyes.…”

Phenyl–Acetylene Bond Assembly: A Powerful Tool for the Construction of Nanoscale Architectures

“…In many instances acetylene couplings are preferential to Suzuki19 or Stille20 direct sp 2 –sp 2 couplings because they can be essential for achieving coplanarity, for increasing π‐conjugation lengths and for decreasing HOMO–LUMO gaps. This has been shown for various chromophores including NDIs,21 oligophenylethynylenes (OPEs),22,23 BODIPYs24 and substituted porphyrins,25 which show marked bathochromic shifts in absorption.…”