Syntheses and Properties of Dimethyl and Tetramethyl Anthra[1,9-cd: 4,10-c′d′]bis[1,2]dichalcogenoles and Their Charge-Transfer Complexes

The dimethyl and tetramethyl derivatives of a series of anthra[1,9-cd : 4,10-c′d′]bis[1,2]dithiole, diselenole, and ditellurole have been prepared as a new type of electron donor. The introduced methyl groups serve to enhance not only the donor strength, but also the solubility, enabling a ready formation of their charge-transfer complexes with various electron acceptors such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), its 2,3,5,6-tetrafluoro derivative, 2,5-dimethyl derivative (DMTCNQ), 2,5-dimethoxy derivative (DMOTCNQ), 2,6-bis(dicyanomethylene)-2,6-dihydronaphthalene (TNAP), 3,3′-dichloro-5,5′-bis(dicyanomethylene)-Δ2.2′-bi(3-thiolene) (DCBT), and 3,3′-dibromo-5,5′-bis(dicyanomethylene)-Δ2.2′-bi(3-selenolene) (DBBS). Although the resulting complexes are mostly 1:1 stoichiometrical, the TCNQ complexes tend to favor a composition rich in acceptors; on the contrary, the DMTCNQ and DMOTCNQ complexes tend to favor a composition rich in donors. Their electrical conductivities range widely from 8 to 10−9 S c...