Asymmetric Dipyrrin and F-BODIPYs Conjugated to Terminal Alkynes and Alkenes

Abstract

An asymmetric meso-H dipyrrin featuring a conjugated terminal alkyne substituent was converted to its corresponding difluoro boron complex, and the extent of π-conjugation was extended using Sonogashira cross-coupling. Treatment of the alkyne-substituted dipyrrin with BF·OEt and NEt revealed the reactivity of the conjugated terminal alkyne toward Lewis-activated electrophilic substitution and led to the isolation of F-BODIPYs bearing terminal bromovinyl and enol substituents.

Polybrominated BOPHY Dyes: Synthesis, Reactivity, and Properties

“…The development of simple and low molecular weight dyes that can be further modified is thus of great interest. Among the synthetic fluorophores studied, boron complexes of π-conjugated chelates often have very promising features, such as high quantum yields, fine-tuned absorption/emission wavelengths, and good photostability. , For example, extensive research on 4,4′-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) has been received because of its excellent photophysical properties and high photostability. − Recently, a BF 2 -complexed hydrazine-Schiff base-linked bispyrrole, bis­(difluoroboron)-1,2-bis­((1 H -pyrrol-2-yl)­methylene)­hydrazine (BOPHY, Figure ), has been developed as a novel small organic fluorescent dye. , This new fluorophore has excellent spectroscopic properties, including high quantum yields of fluorescence, high molar extinction coefficients, highly tunable absorption/emission profiles, and excellent photostability. In addition, BOPHY dyes have larger Stokes shifts and higher solid-state fluorescence than those of classical BODIPY dyes, which generally suffer from small Stokes shifts ,, and relatively weak solid-state fluorescence.…”

Synthesis of Polysubstituted Symmetrical BODIPYs via Fischer Carbene Complexes: Theoretical, Photophysical and Electrochemical Evaluation

“…Although there are few papers related to prefunctionalization, because sometimes the synthesis is focused on the preparation of a particular type of BODIPY or pathways can be lengthy and with low yields, this approach allows easier access to specific functionalizations than with the postfunctionalization approach [16–25] . Conversely, postfunctionalization relies on the reactivity of the BODIPY core to selectively add different substituents into its structure, but this involves several reaction steps [26–32] . Thus, the two approaches of pre‐ and postsubstitution are often complementary strategies.…”

Accessing the Ene–Imine Motif in 1H-Isoindole, Thienopyrrole, and Thienopyridine Building Blocks

“… 6 , 7 Building blocks containing the ene–imine moiety, as highlighted in Figure 1 , are rarely encountered in the literature despite the importance of this fragment in porphyrins 8 and other π-extended structures such as BODIPY 5 . 9 …”

“…Molecular building blocks possessing discrete conjugated segments that can be combined with other conjugated molecular units in a facile manner are widely utilized in pharmaceuticals and organic electronics . Moieties such as diketopyrrolopyrrole 1 and isoindigo 2 are widely used in the latter field for the synthesis of conjugated small molecules and polymers. , Despite the many advances using these and similar building blocks, the development of new heterocycles such as lactam 3 and thiophenium salts 4 is a critical factor in learning how to control the properties of organic materials. , Building blocks containing the ene–imine moiety, as highlighted in Figure , are rarely encountered in the literature despite the importance of this fragment in porphyrins and other π-extended structures such as BODIPY 5 …”