Construction of Subphthalocyanine−Porphyrin and Subphthalocyanine−Phthalocyanine Heterodyads through Axial Coordination

The treatment of boron(III) subphthalocyanine chloride (SPcCl) with 3- or 4-hydroxypyridine in the presence of pyridine in toluene gave the corresponding boron(III) subphthalocyanine pyridinolates SPc(3-OPy) (1) or SPc(4-OPy) (2). Having a pyridyl group, these compounds could axially complex with a series of zinc(II) and ruthenium(II) porphyrins and phthalocyanines to form the corresponding subphthalocyanine−porphyrin and subphthalocyanine−phthalocyanine heterodyads. As revealed by UV−vis spectroscopy, the ground-state interaction between the two chromophores in these dyads is insignificant. The complexation processes were also studied by 1H NMR and fluorescence spectroscopic methods, which confirmed the 1:1 binding stoichiometry. The association constants, as determined by fluorescence titration, were generally higher for the ruthenium(II) tetrapyrroles [(2.5−4.7) × 104 M−1] than for the zinc(II) counterparts [(0.3−1.8) × 104 M−1]. The molecular structures of the two pyridyl subphthalocyanines 1 and 2, together with three novel subphthalocyanine−porphyrin heterodyads, were also determined by X-ray diffraction analyses.