Highly Fluorescent Self‐Coordinated Phthalocyanine Dimers

Abstract

Head‐to‐tail self‐assembly of two imidazolylphthalocyaninatozinc(II) or ‐magnesium(II) units through mutual imidazole–metal interactions leads to strongly fluorescent dimers (see picture, ΦF=fluorescence quantum yield) that exhibit high association constants estimated at over 1011 M−1 in toluene.

Solvent effects on molecular aggregation of highly water-soluble phthalocyanines

“…H-aggregate) [23-27, 29-31, 34, 36, 39] due to strong p-p interaction between chromophores, it is understandable that the antimony-complex molecules align in a slipped-cofacial manner because of the presence of two hydrophilic and bulky axial ligands, which prevent H-aggregation of the macrocycles [21]. Thus J-aggregation is much less common for phthalocyanines unless steric hindrance occurs due to the presence of either axial ligand(s) on the metal ion [20,21,31,37], or the metal ion itself protrudes from the cavity of the macrocyclic ligand [19,[40][41][42], or something else [43]. Nevertheless, the copper ion in Cu(Pc) has no axial ligand on the basis of its mass spectrum [22] and is quite likely to be located within the molecular plane of the macrocycle [44].…”

“…Nevertheless, the copper ion in Cu(Pc) has no axial ligand on the basis of its mass spectrum [22] and is quite likely to be located within the molecular plane of the macrocycle [44]. Kobuke's group has reported rigid slipped-cofacial dimers of phthalocyanine complexes bearing an imidazolyl group as a peripheral substituent which coordinates to another metal ion in the cavity of its macrocyclic ligand [43]. Substituents of the macrocyclic ligand in this study also have sulfonic acid groups, which are capable of coordination to a metal ion in the cavity of another macrocycle.…”

Synthesis and properties of azaphthalocyanines with 1,2,3,4-tetrahydropyrazino[2,3-b]pyrazine moiety

“…with new bands at longer wavelengths indicates usually presence of J-dimers. [27] These were even described and characterized for structurally similar octakis(diethylamino)-azaphthalocyanine but only for zinc complex and the red-shift was not so strong (λ max = 700 nm). [19] The reported J-dimers were based on a coordination bond between the peripheral diethylamino substituent and central zinc, i.e.…”

Aluminum Phthalocyanine on Silica Nanoparticles: Aggregation and Excited States

“…[9] It is supposed that H-aggregates of Pc, which are most often formed in many systems, are not photoactive, in contrast to J-aggregates, which could be photoactive, but are formed much more rarely. [10,11] First of all the studies of nanostructured Pc are mainly focused on the development of the method of preparation of the aggregate with a necessary structure. However, the study of nanostructured Pc was not concerned with a research of their photochemical features whereas they could be used in photodynamic therapy, fluorescent diagnosis of pathologic states, and as vectors for targeted drug delivery.…”