Synthesis and properties of amino acid functionalized water-soluble perylene diimides

Abstract

We prepared amino acid functionalized water-soluble perylene diimides: N,N′-bi(L-glutamic acid)-perylene-3,4;9,10-dicarboxylic diimide (1), N,N′-bi(L-phenylalanine acid)-perylene-3,4;9,10-dicarboxylic diimide (2), N,N′-bi(L-glutamic amine)-perylene-3,4;9,10-dicarboxylic diimide (3) and N,N′-bi(L-phenylalanine amine)-perylene-3,4;9,10-dicarboxylic diimide (4). The structures of 3 and 4 were confirmed by ¹H NMR, FT-IR and MS. The maximal absorption bands of compound 1 and 2 in concentrated sulfuric acid were red-shifted for about 48 and 74 nm, respectively, compared with that of Perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA). Nearly no fluorescence was observed for compounds 1 and 2 in water, while compounds 3 and 4 were significantly water-soluble and had very high fluorescent quantum. The mechanism of the optical properties change was discussed, and the π-π stacking caused by H⁺ led to the changes of fluorescence spectrum and absorption spectrum. The calculated molecular orbital energies and the frontier molecular orbital maps of compounds 1–2 based on density function theory (DFT) calculations were reported. Owing to the high water-soluble, the perylene derivatives 3 and 4 were successfully applied as high-performance fluorochromes for living hela cells imaging.