The Ugi Four‐Component Reaction Route to Photoinducible Electron‐Transfer Systems

Unimolecular Exciplexes by Ugi Four-Component Reaction

“…The Ugi four-component reaction (4CR) (Dömling and Ugi, 2000; Dömling, 2006; Biggs-Houck et al, 2010) generates the chemically robust α-aminoacyl amide scaffold with a high level of diversity and has widely and successfully been applied in biological and medicinal chemistry (Dömling et al, 2012). Encouraged by Ugi 4CR syntheses of a phenothiazine-anthraquinone-based PIET system and related dyads (Bay et al, 2013, 2014; Bay and Müller, 2014), characterized by cyclic voltammetry, steady-state UV/vis, and fluorescence spectroscopy, as well as femtosecond transient absorption spectroscopy for identification of the desired charge separated state after light excitation, we decided to transpose the Ugi 4CR to a novel synthesis of N,N -dimethylaniline-anthracene dyads, which are known to form exciplex emitters (Hui and Ware, 1976).…”

“…As part of our program to methodologically develop concise syntheses of functional chromophores by multicomponent reactions (MCR) (Levi and Müller, 2016a), we are particularly interested in MCR syntheses of fluorophores (Levi and Müller, 2016b; Riva et al, 2016; Merkt and Müller, 2018; Müller, 2018) and donor-acceptor systems that interact in the excited state via photo-induced electron transfer (PIET) (Kavarnos, 1993; Lemmetyinen et al, 2011; Wenger, 2011; Ricks et al, 2012; Vauthey, 2012), as shown by non-radiative fluorescence quenching (Bucci and Müller, 2006; Bay et al, 2013, 2014; Bay and Müller, 2014). This can be considered as chromophore-chromophore interactions at short distances, that is, between Dexter and Förster radii.…”

Preservation of the donor–acceptor character of a carbazole–phenalenone dyad upon adsorption on Pt(111)

“…2 Donor-acceptor dyads enable intramolecular electron transfer induced by thermal, electrical or optical stimulation and oen show uorescence or solvatochromism. [3][4][5][6][7] However, the application of donor-acceptor dyads in advanced devices requires a careful molecular design regarding the efficiency of electron transfer and the lifetime of the charge separated state. Several factors have been suggested to enhance the quantum yields and lifetimes in the charge separated states, such as spin restriction rules, conformational gating, and orientation effects.…”

“…Found: C 84.11, H 5.10, N 4.99. [4-(9H-Carbazol-9-yl)phenyl]methanol(4). In an oven dried nitrogen-ushed screw-cap Schlenk tube with magnetic stir bar were placed 4-(9H-carbazol-9-yl)benzaldehyde (3) (712 mg, 2.62 mmol) in methanol (10 mL) under nitrogen.…”

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

“…In previous studies phenothiazine–anthraquinone couples have been introduced into peptide scaffolds [ 52 – 54 ] and rigid Do–Acc dyads [ 55 ]. Nevertheless, a modular and rapid access by multicomponent reactions to these types of functional targets has never been explored prior to our recent studies [ 56 ]. For instance, the Ugi four-component reaction (Ugi 4CR) [ 57 – 60 ] establishes the chemically robust α-aminoacylamide backbone in one step and with high diversity.…”