Revealing Topological Influence of Phenylenediamine Unit on Physicochemical Properties of Donor‐Acceptor‐Donor‐Acceptor Thermally Activated Delayed Fluorescent Macrocycles

A new thermally activated delayed fluorescence (TADF)‐displaying macrocyclic compound m‐1 comprising of two electron‐donors (N,N’‐diphenyl‐m‐phenylenediamine) and two electron‐acceptors (dibenzo[a,j]phenazine) has been synthesized. The macrocycle developed herein is regarded as a regioisomer of the previously reported TADF macrocycle p‐1, which has two N,N’‐diphenyl‐p‐phenylenediamines as the donors. To understand the influence of the topology of the phenylenediamine donors on physicochemical properties of TADF‐active macrocycles, herein the molecular structure in the single crystals, photophysical properties, electrochemical behavior, and TADF properties of m‐1 have been investigated compared with those of p‐1. The substitution of p‐phenylene donor with m‐phenylene donor led to distinct positive solvatoluminochromism over the full visible‐color range, unique oxidative electropolymerization, and slightly lower contribution of TADF, due to the lower CT character in the excited states. A new donor‐acceptor‐donor‐acceptor macrocyclic π‐conjugated compound comprising of two electron‐donors (N,N’‐diphenyl‐m‐phenylenediamine) and two electron‐acceptors (dibenzo[a,j]phenazine) has been synthesized, and its structure and physicochemical properties have been investigated. In comparison with para‐linked macrocyclic analogue, the influence of topology of the phenylenediamine donors on properties has been revealed.