Structure and properties of radical anion and dianion salts of organic dye trans-perinone and its mixed salt with gallium(III) phthalocyanine

Reduction of organic dye trans-perinone (its abbreviation is perinone) in different experimental conditions allows us to obtain and characterize radical anion {cryptand(K+)}[perinone(center dot-)] (1) and dianion {PPN+}(2)[perinone(2-)]center dot 2C(6)H(4)Cl(2) (2) salts of this dye. The salts have layered structures. Perinone(-) radical anions form pi-pi stacked dimers in 1 with an effective interaction between them, whereas perinone(2-) dianions are isolated in 2. Reduction of perinone is accompanied by an essential red shift of the absorption bands of the starting dye and, as a result, the salts have absorption nearly in the whole visible range. Strong coupling of spins is observed in the pi-stacking [perinone(center dot-)](2) dimers of 1, which are described by the Heisenberg model for isolated pairs of antiferromagnetically interacting spins with J/k(B) = -38 K. The triplet excited state of the dimers is populated above 50 K. The EPR signal of 1 shows features characteristic of triplets, and the average separation of spins within the dimers estimated in the point-dipole approximation is 8.7 angstrom. The dimers manifest an intense charge transfer band with a maximum at 1356 nm. A mixed {cryptand(K+)}[(perinone)(0.5)((GaClPc)-Cl-III)](-)center dot 3C(6)H(4)Cl(2) (3) salt with two anionic chromophores - perinone and gallium chloride phthalocyanine - is also obtained in the crystalline form. It has only one negative charge and spin per [(perinone)(0.5)((GaClPc)-Cl-III)] unit. As a result, the magnetic behavior of 3 is described well by contributions from isolated perinone(center dot-) radical anions and {(GaClPc)-Cl-III}(2)(-) dimers with effective pi-pi stacking between phthalocyanines and one negative charge and S = 1/2 spin per dimer.