Synthesis and Tunable Fluorescence of N,N‐Disubstitute ortho‐Aminostyryl D‐π‐A Chromophores Based on a Hydroxytricyanopyrrole (HTCP) Acceptor

The first 13 examples of ortho-aminostyryl D-p-A chromophores with a tunable HTCP acceptor are presented. A simple modification of the HTCP acceptor is shown. The emission maxima in the solid state vary in the red region in the range of 619–669 nm. The quantum yield of solid-state fluorescence increases upon modification of the acceptor fragment with HTCP.

Abstract

The first representatives of a new group of fluorescent donor-acceptor chromophores, the key structural fragments of which are an easily modifiable hydroxytricyanopyrrole (HTCP) acceptor and an N,N-disubstituted ortho-aminostyryl donor fragment, were synthesized. By changing the substituent on both the donor and acceptor fragments, the possibility of varying the emission maxima in the solid state in the red region in the range of 620–732 nm was achieved. It was shown that the introduction of an alkoxy group into the pyrrole ring of HTCP leads to an increase in the quantum yield (Φ_c) of solid state emission to 9.5 %. In the liquid phase HTCP-chromophores fluoresce in the range of 621–639 nm with a relative quantum yield of up to 5.5 % The energy values found for the band gap of HTCP chromophore with ortho-morpholinostyryl donor fragment were in the range of 2.38–2.41 eV.

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