Supramolecular dendritic π-conjugated systems: Enhancement of fluorescence in amorphous dendritic blue emitting thin film

Glycinylurea functionalized π-conjugated diphenylanthracene guests (DPA guests) that bind to adamantyll urea modified dendritic hosts were synthesized and fully characterized optical measurements. The resulting supramolecular assemblies have been investigated with respect to their photophysical properties. DPA guests molecules were able to click into urea functionalized N,N-bis[(3-adamantyl ureido) propyl] methyl amine host as a result of acid-base (between COOH of the guest and amines of the host) and hydrogen bonding interactions (between the urea linkages of dendrimer and the guest). Size exclusion chromatography showed that 32 of the DPA guests strongly bind to the fifth generation adamantyl functionalized dendritic host. In the case of the supramolecular dendritic host/guest system smooth homogeneous thin films could be obtained by spin coating. The thin film of host-guest complexes shows brilliant blue fluorescence while in the case of the guest itself the fluorescence is quenched. Then-conjugated oligomers are less aggregated in the supramolecular assemblies presumably because of a shielding effect of the bulky adamantyl units present in the hosts.