Synthesis and Properties of Non-planar Extended Quinonoid Molecules Aimed for Molecular-switching Function

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Our research results are summarized as follows.1. Synthesis and properties of various non-planar dibenzoannetated terphenoquinonesIn order to study substituent effect on the switching process, we have synthesized a number of non-planar dibenzoannelated 3,3",5,5"-tetra-t-butylterphenoquinone derivatives. The most notable feature is the stabilization of the diradical structure of the 1,8-dimethoxy derivative.2. Synthesis and Properties of benz[d,e]anthracenylidene-p-quinone methidesWe studied the synthesis and properties of two non-planar p-quinone methides, 6H- and 7H-benz[d,e]anthracenyilidene p-quinone methides. The 6H-isomer is deep purple crystals which shows slight solvatochromism, whereas the 7H-isomer is orange crystals, indicating no solvent effect. The rotation of central double bond in 7H-isomer is observed at room temperature.3. Synthesis and properties of non-planar quinonoid compounds having 1,2-diketone structureA dibenzo-ortho-terphenoquinone derivative, the first o-terquinone derivative, is largely deviated from coplanarity, is in a slight equilibrium with its diradical form, displays an easy rotation of the exocyclic double bonds, and shows photo-responsive switching property traceable by ESR spectroscopy.