Iron-Catalyzed Synthesis, Structure, and Photophysical Properties of Tetraarylnaphthidines

Abstract

We describe the synthesis and photophysical properties of tetraarylnaphthidines. Our synthetic approach is based on an iron-catalyzed oxidative C–C coupling reaction as the key step using a hexadecafluorinated iron–phthalocyanine complex as a catalyst and air as the sole oxidant. The N,N,N’,N’-tetraarylnaphthidines proved to be highly fluorescent with quantum yields of up to 68%.

Iron‐Catalyzed Oxidative C−O and C−N Coupling Reactions Using Air as Sole Oxidant**

“…However, the complex tris(dibenzoylmethanato)iron(III) (Fe[dbm] 3 ), [30] phthalocyanine–iron(II) (FePc), and hexadecafluorophthalocyanine−iron(II) (FePcF 16 ) afforded compound 7 a in 15–27 % yield (entries 4–6). The high catalytic activity of FePcF 16 for various oxidative transformations has been widely demonstrated by our group [15–18,20,31,32] . Subsequently, we have screened a range of different additives for the oxidative C−N bond formation using 4 mol% of FePcF 16 as catalyst (entries 7–13).…”

“…The high catalytic activity of FePcF 16 for various oxidative transformations has been widely demonstrated by our group. [15][16][17][18]20,31,32] Subsequently, we have screened a range of different additives for the oxidative CÀ N bond formation using 4 mol% of FePcF 16 as catalyst (entries 7-13). With methanesulfonic acid as additive (entry 7), complete decomposition of the starting material was observed.…”

“…Recently, we have developed an oxidative C−C homocoupling of anilines [15,16] and hydroxycarbazoles, [17] as well as an oxidative C−C cross‐coupling of tertiary anilines with hydroxyarenes [18] using hexadecafluorophthalocyanine−iron(II) (FePcF 16 , Figure 1) [15,19] as catalyst with air as sole oxidant [20] . The iron‐catalyzed reaction of 2‐(dimethylamino)naphthalene with 2‐naphthol afforded the oxidative C−C cross‐coupling product (62 % yield) along with a diaryl ether (11 % yield) resulting from an oxidative C−O coupling reaction [18] .…”

On the Protonation and Deuteration of Per‐Arylated Amines**

“…The results of the protonation/deuteration experiments of triphenylamine (7) stimulate us to study the same reactions with some other triarylamines also. As first example, 1-(N,Ndiphenyl) (8) was studied. This compound is, as indicated by 1 H NMR measurements, not protonated by TFA, but protonated by TFS at its amino group yielding the ammonium salts 8H N + .…”

“…The authors thanks Mrs. Anett Rudolf for measurement the NMR spectra and Prof. Dr. H.-J. Knölker, Professur für Organische Chemie 2, Fakultät Chemie und Lebensmittel-chemie, Technische Universität Dresden, for providing the 1-(N,N-diphenyl) (8), prepared accordingly to Ref. [8].. Open Access funding enabled and organized by Projekt DEAL.…”