SnPhPc phthalocyanines with dianion Pc2- and radical trianion Pc3- macrocycles: Syntheses, structures, and properties

Abstract

The interaction of SnIVCl2Pc with an excess of NaBPh4 in the presence of fullerenes C60 and C70 provides complete dissolution of SnIVCl2Pc and the formation of blue solutions from which the crystals of [SnPhPc2-]+(BPh4)-·C6H14 (1) or [SnPhPc3-]·C6H4Cl2 (2) were selectively isolated. According to the optical spectra, salt 1 contains dianionic Pc2- macrocycles, whereas macrocycles are reduced to form the Pc3- radical trianions in 2. As a result, the phthalocyanine macrocycle is dianionic in 1, and the positive charge of SnIV is compensated by the Ph-, Pc2-, and BPh4- anions in this compound. The formally neutral compound 2 contains two anionic species of Ph- and Pc3- and the SnIV ion as the counter cation. Phenyl substituents are linked to the SnIV atoms by the Sn-C(Ph) bonds of 2.098(2) (1) and 2.105(2) Å (2) length. The dianionic Pc2- macrocycle significantly deviates from planarity in 1 while Pc3- is planar in 2. Salt 1 manifests only a weak impurity EPR signal. Compound 2 manifests an intense EPR signal with g = 2.0046 and a linewidth of 0.5 mT at 298 K due to the presence of Pc3-. Spins are weakly antiferromagnetically coupled in the π-stacking [SnPhPc3-]2 dimers of 2 with a Weiss temperature of -3 K and the estimated magnetic exchange interaction J/kB = -0.23 K.