Self‐Assembled Azaphthalocyanine Dimers with Higher Fluorescence and Singlet Oxygen Quantum Yields than the Corresponding Monomers

Abstract

In this work, we describe diethylamino-substituted metal azaphthalocyanines that form self-assembled J-dimers in noncoordinating solvents. The dimers are formed by the coordination of the free electron pair of one diethylamino group with the central metal of the adjacent molecule. The addition of pyridine leads to monomerization and considerable quenching of fluorescence and singlet oxygen formation as

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

“…[13,19] Moreover, the tetrahydropyrazine ring allows simple influence of electron density on the donor centers (nitrogens in positions 5 and 8) by different substituents (Scheme 1) which makes them highly interesting for photochemical studies. Ethyl, phenyl and benzyl were chosen as an example and compounds 1-3 were synthesized using nucleophilic substitution by corresponding ethane-1,2-diamines (Scheme 1) in the presence of K 2 CO 3 .…”

“…[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. they cannot occur at metal-free derivatives (e.g.…”

Synthesis of Stable Dimeric Phthalocyanine J-Type Complexes and Investigation of Their Nucleophilic Properties

“…A t -is the current value of optical density of the solution on the analytical wavelength; A 0(B) , A 0(HB + ) and A 0(H 2 B 2+ ) -are optical densities of the components corresponding to the analytical concentration of phthalocyanine; K b1 and K b2 -are the constants of reactions (2) and (3). To the spectropotentiometric cell the solution of phthalocyanine 2b in methanol (90 mL) with the given optical density (A = 1.05 a.u.)…”

“…Two types of ordered assemblies -H-and J-have been known today, with their diversity being depended on the direction of the dipole moment of the interacting monomer components in the process of transition from the ground to the excited states. [3] According to the Kasha's molecular exciton theory, [4] if the angle between the polarization direction of the monomer and the line passing through the center of the aggregate (e.g. slip angle), is more than 54.7°, such aggregate (H-type) demonstrates the presence of an additional band in the UV-Vis spectrum which is blue-shifted towards the major intense band (Q-band).…”

“…low-symmetry phthalocyanines), instead of aggregates the dimers of similar structure are formed. [3,7] Dimers and aggregates of J-type are of interest for a number of studies, and only to date they were able to be isolated from the solutions as individual compounds. So, we have synthesized, for the first time, of thermally stable dimeric J-type phthalocyanine complexes and studied of axial coordination and peripheral functionalization processes as well.…”