CHARGE-TRANSFER INTERACTIONS OF ZINC-II TETRANEOPENTOXYPHTHALOCYANINE WITH 2,3-DICHLORO-5,6-DICYANO-P-BENZOQUINONE

Charge transfer interactions of zinc(II) tetraneopentoxyphthalocyanine (ZnTnPc(2-)) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) were investigated electrochemically and spectroscopically. DDQ oxidizes ZnTnPc(2-) by one electron to its cation radical, [ZnTnPc(1-)]+, and is reduced to the semiquinone form, [DDSq(1-)]-. A redox series of species were investigated by controlled-potential reduction and spectroelectrochemical methods. The possible existence of [ZnTnPc(1-).DDSq(1-)], [ZnTnPc(2-).DDSq(1-)]-, [ZnTnPc(-2).DDCat(2-)]2-, and [ZnTnPc(3-).DDCat(2-)]3- is discussed. UV-vis, ESR, FTIR, cyclic and differential pulse voltammetry, and spectroelectrochemical data are presented. Bonding between the zinc metal of the phthalocyanine and the cyanide nitrogen of the quinone is proposed on the basis of AM1 calculations.