Influence of Surfactant-based Microheterogeneous Fluids on Aggregation of Copper Phthalocyanine Tetrasulfonate

Abstract

<jats:p> Electronic absorption spectroscopy was used to measure the molecular association of copper phthalocyanine tetrasulfonate in micellar solutions, a microemulsion made with cationic surfactant, and homogeneous solvents. Analysis of absorbance versus concentration data using a multiple-aggregation model and non-linear regression analysis gave values of association constants, molar absorptivities and estimates of average aggregation number. Microemulsions and aqueous micellar solutions made with alkylammonium surfactants inhibited aggregation, probably because of interactions between the phthalocyanine sulfonate groups and the cationic surfactant head groups at interfacial surfaces. Similar aggregation behavior was observed previously in multiple-bilayer films of cationic surfactants. Water and aqueous solutions containing tetraethylammonium bromide or anionic SDS micelles provide environments facilitating extensive aggregation of Cu <jats:sup> II </jats:sup> PcTS <jats:sup>4−</jats:sup>. The major species are dimers in water and acetonitrile/water, but the formation of higher aggregates is promoted by addition of SDS or TEAB. Aprotic organic solvents provide environments intermediate between these two extremes, giving relatively large aggregation numbers (i.e. five to seven) but smaller association constants than aqueous media not containing cationic surfactants. </jats:p>

Cyclic Tetrapyrrole Sulfonation, Metals, and Oligomerization in Antiprion Activity

“…The spectra of various sulfonates in graded DMSO-PBS mixtures were determined. The ability of DMSO to stabilize these compounds as monomeric species and the ability of aqueous media to promote their aggregation are well established (21,24). Spectra can vary widely with changes in aggregation state and, hence, with mixtures of PBS and DMSO solvents.…”

Synthesis and selected properties of metallo and metal-free 2,3,9,10,16,17,23,24 –octacarboxyphthalocyanines

“…(Figure 3). 40,54 For FePcOC in a solution with pH of 7.0 a dimer band and a monomer band can be seen at 634 nm and at 680 nm respectively. However, regardless of the presence in the spectrum of dimer band, iron octacarboxyphthalocyanine occurs mainly in the monomeric form due to the electrostatic repulsion of negatively charged carboxylic groups (dissociation of eight carboxyl groups at this pH value).…”

“…The  max position of trimer band and higher aggregated compounds occur usually between 600 and 630 nm. 53,54 Whereas the intensive band at 660-700 nm, typical for the monomeric form, is bathochromically shifted about 30-70 nm against the  max of the dimer band. The B band also undergoes a bathochromic shift but to a much lesser extent.…”

Behaviour of Low-Symmetry Crown-Phthalocyanine in Solution: Concentration Aggregation vs. Cation-Induced Assembly

“…[32][33][34][35] For example, the authors of paper [36] suggest graphical analysis of UV-Vis spectra of series of concentrated solutions of chromophore molecules, based on the following equation:…”