Dimerization and Coordination Properties of Zinc(II)tetra-4-alkoxybenzoyloxiphthalocyanine in Relation to DABCO in o-Xylene and Chloroform

Abstract

For the first time the interactions between zinc(II)tetra-4-alkoxybenzoyloxiphthalocyanine (Zn(4—O—CO—C6H4—OC11H23)Pc) and 1,4-diazabicyclo[2.2.2]octane (DABCO) in o-xylene and chloroform have been studied by calorimetric titration and NMR and electron absorption spectroscopic methods. It has been found that in o-xylene at concentrations of Zn(4—O—CO—C6H4—OC11H23)Pc higher than 6×10−4 mol⋅L−1π–π dimers species are formed (λmax= 685 nm). Additions of DABCO to the solution up to mole ratio 1 : 8 (Zn(4—O—CO—C6H4—OC11H23)Pc : DABCO) lead to a shift of the aggregation equilibrium towards monomer species due to formation of monoligand axial complexes. Further increasing the DABCO concentration results in formation of Zn(4—O—CO—C6H4—OC11H23)Pc—DABCO—Zn(4—O—CO—C6H4—OC11H23)Pc sandwich dimers (λmax= 675 nm).