Switch‐ON Near IR Fluorescent Dye Upon Protonation: Helically Twisted Bis(Boron Difluoride) Complex of π‐Extended Corrorin

Abstract

A novel helically twisted π-extended corrorin derivative having two boron dipyrrin (BODIPY) moieties at the periphery, a BODIPY DYEmer (6-BF ) cross-bridged with π-conjugated dipyrrinylidene unit, was synthesized and characterized. The neutral 6-BF is nonfluorescent due to the internal photoinduced charge transfer (CT) character in the excited state as inferred from the femtosecond transient absorption spectroscopy. However, upon protonation, the CT process is suppressed and the species H6-BF becomes near infrared (IR) emissive. With the aid of rigid helical conformations in 6-BF , the helical isomers (P- and M-forms) were resolved and their chiroptical property was investigated. The distinct circular dichroism (CD) spectral changes of the enantiomers were observed in the presence of acids, which demonstrates that 6-BF can be utilized for potential acid-responsive chiroptical materials.

Vinylene-Bridged Cyclic Dipyrrin and BODIPY Trimers

“…EDDMs of 3BF 2 -Me-Hex(a) and 3BF 2 -Me-Hex(b) are delocalized on the whole molecules, whereas the location of EDDMs for the lowest HOMO-LUMO transitions of BF 2 -Me-Hex, 2BF 2 -Me-Hex(a), and 2BF 2 -Me-Hex(b) is shifted from the free base dipyrrin units to the BODIPY units. The predicted ICT characteristics of BF 2 -Me-Hex, 2BF 2 -Me-Hex(a), and 2BF 2 -Me-Hex(b) are consistent with their non-emissive behavior in solution upon photoexcitation [25][26][27]. Generally, BODIPY compounds show strong emission.…”

“…In contrast, 3BF 2 -Me-Hex(a) and 3BF 2 -Me-Hex(b) exhibit a π-π transition. The electron density difference map (EDDM) represents the difference in electron densities upon electronic transitions (Figure 8) [27]. EDDMs of 3BF 2 -Me-Hex(a) and 3BF 2 -Me-Hex(b) are delocalized on the whole molecules, whereas the location of EDDMs for the lowest HOMO-LUMO transitions of BF 2 -Me-Hex, 2BF 2 -Me-Hex(a), and 2BF 2 -Me-Hex(b) is shifted from the free base dipyrrin units to the BODIPY units.…”

Synthesis, characterization of 1,3-dimethyl-5-(3,5-dimethylphely)aminomethylenebarbiturate boron difluoride complex and investigation of photophysical properties

“…11 B NMR spektrumunda 1 ppm'de görülen kimyasal kayma değeri tetra koordine bor atomu içeren bileşikler için beklenen aralıktadır. Ayrıca bu değer benzer BF 2 kompleksleri için rapor edilmiş değerler ile örtüşmektedir [16][17][18].…”

The Curious Case of a Parasitic Twin of the Corroles

“…In this direction, it will be interesting to see the effect of lateral π‐extension of an existing π‐electronic pathway of a smaller porphyrinoid . To this effect, herein we report the synthesis and electronic structure of hexaphyrins 4 and 4‐Rh (Figure ) obtained by π‐expansion of a ring‐contracted porphyrinoid.…”