Spiroconjugated Tetraaminospirenes as Donors in Color‐Tunable Charge‐Transfer Emitters with Donor‐Acceptor Structure

Charge‐transfer emitters are attractive due to their color tunability and potentially high photoluminescence quantum yields (PLQYs). We herein present tetraaminospirenes as donor moieties, which, in combination with a variety of acceptors, furnished 12 charge‐transfer emitters with a range of emission colors and PLQYs of up to 99 %. The spatial separation of their frontier molecular orbitals was obtained through careful structural design, and two DA structures were confirmed by X‐ray crystallography. A range of photophysical measurements supported by DFT calculations shed light on the optoelectronic properties of this new family of spiro‐NN‐donor‐acceptor dyes. Emitters go spiro: Using spiroconjugated tetraamines as a novel type of donor and a range of different acceptors in three different modes of connection, 12 donor‐acceptor compounds are synthesized. Their twisted structures lead to a spatial separation of the HOMOs and LUMOs. Photophysical measurements show tunable emission colors for these donor‐acceptor compounds, and photoluminescence quantum yields of up to 99 % in solution are obtained.