Novel group of negative photochromes containing a nitrile-rich acceptor: synthesis and photochromic properties

An approach to the synthesis of novel group of negative photochromes has been developed based on the interaction of the tricycanofuran TCF or hydroxytricyanopyrrole HTCP acceptors with methoxy-substituted 2-hydroxybenzaldehydes in ethanol in the presence of ammonium acetate. An essential part of the obtained photochromes is a combination of a phenol fragment and a butadienetricarbonitrile BDTC acceptor connected via a vinylene bridge. The synthesized compounds are sensitive to visible light T-type photochromes. A transformation degree of the initial form, as well as the rate of the reverse dark reaction, can be varied by changing both the position of a methoxy group at aromatic ring and the type of the heterocycle with the BDTC fragment.