Radoslaw Motyka

Symmetrical and unsymmetrical α,ω-nucleobase amide-conjugated systems

Summary We present the synthesis and selected physicochemical properties of several novel symmetrical and unsymmetrical α,ω-nucleobase mono- and bis-amide conjugated systems containing aliphatic, aromatic or saccharidic linkages. The final stage of the synthesis involves condensation of a subunit bearing carboxylic group with an amine subunit. 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) was found to be a particularly effective condensing agent. The subunits containing carboxylic groups were obtained by acidic hydrolysis of N-1 Michael adducts of uracils or N-9 Michael adducts of 6-chloropurine with methyl acrylate. The amines used were aliphatic/aromatic diamines, adenine, 5-substituted 1-(ω-aminoalkyl)uracils and 5′-amino-2′,5′-dideoxythymidine. The title compounds may find application as antiprotozoal agents. Moreover, preliminary microscopy TEM studies of supramolecular behaviour showed that target molecules with bolaamphiphilic structures were capable of forming highly ordered assemblies, mainly nanofibres.

Thermally activated delayed fluorescence with a narrow emission spectrum and organic room temperature phosphorescence by controlling spin–orbit coupling and phosphorescence lifetime of metal-free organic molecules

This work presents a study of two organic molecules with a very similar, large singlet–triplet energy gap, one of which is a thermally activated delayed fluorescence (TADF) emitter and the other is a room temperature phosphorescence (RTP) emitter. By investigating their photophysical properties we are able to explain their distinct behavior. The molecules are studied in non-polar polymers and OLED hosts. Furthermore, this work presents a CT TADF emitter that shows a narrow and resolved electroluminescence spectrum (FWHM = 53 nm). The study shows an efficient RTP emitter based on a D–D–D structure and also the first acridone-based TADF emitter with a D–A–D structure.