Preparation and characterization of SDS-stabilized hydrophobic porphyrinic nanoaggregates in water

Abstract

Porphyrin nanoaggregates formed in the interior of colloidal suspensions can be considered as examples of supramolecular systems with self-organized architecture. Due to their peculiar optical and electrochemical properties such as decrease of fluorescence, increase of conductivity and possible electron transfer, these aggregates can be used in the design and fabrication of optoelectronic devices, such as organic solar cells and optical and electrochemical sensors. In this paper, we first describe the synthesis of a series of hydrophobic tetraphenylporphyrins by a change in the order of reagents addition that results in high yields of the desired products. These products were then employed to obtain stable suspensions of porphyrinic nanoaggregates in aqueous solutions of sodium dodecyl sulfate (SDS). The aggregates resulting of the encapsulation of the tetraphenylporphyrins into the micelles of the surfactant were studied by dynamic light scattering (DLS), atomic force microscopy (AFM) and UV-vis and fluorescence spectroscopies. The results indicate that the nanoggregates have a spherical morphology with particles whose average size ranges between 46–78 nm and ζ-potential values (higher than 55 mV), indicative of excellent stability. Optical characterization was used to determine the classification of nanoaggregates, according to the observed shifts on the absorption spectra.

Insertion of Ni(I) into Porphyrins at Room Temperature: Preparation of Ni(II)porphyrins, and Ni(II)chlorins and Observation of Hydroporphyrin Intermediates

“…5,10,15,20-Tetra­(4-methoxyphenyl) porphyrin (TPPOMe) 1a , tetraphenylporphyrin (TPP) 1b , and meso -tetrakis­(pentafluorophenyl)­porphyrin (TPPF 20 ) 1c were synthesized as reported. − …”

Elucidating the Reaction Kinetics of Hydrophobic Porphyrin Nanoaggregates Dispersed in PVA Films Exposed to HCl Vapors

“…Zinc porphyrinate was obtained by refluxing Zn acetate (BDH, Germany) together with porphyrin in dimethylformamide from Sigma‐Aldrich (Brazil) for 20 min, with subsequent precipitation in cold water and vacuum filtering. The water dispersions of hydrophobic porphyrin stabilized with sodium dodecyl sulfate (SDS) were obtained as previously reported , where we start by using a preemulsion of 0.1 g porphyrin dissolved in 10 mL of chlorophorm and the SDS aqueous solution, which was stirred for about 1 h. Then, after 3 min of ultrasonication of the predispersion at 90 W, we obtained a microemulsion that was rotoevaporated to remove the organic solvent the emulsion.…”

Thermodynamic study of the interaction between 5,10,15,20-tetrakis-(N-methyl-4-pyridyl)porphyrin tetraiodine and sodium dodecyl sulfate

“…In the second step, 5,10,15,20-tetrakis(4-pyridyl)porphyrin was methylated using methyl iodide and conventional methods, yielding the desired porphyrin as a dark-purple solid in 94% yield, Scheme 1 [25]. Scheme 1 in here M a n u s c r i p t 6 …”

“…It is known that porphyrin aggregation, resulting from intermolecular interactions, often occur in aqueous solutions even at very low (< 1 mM) concentrations leading to a decrease in the electrical conductivity (in the case of ionic porphyrins) and suppressing the fluorescence [6] and ability of these compounds to generate singlet oxygen [7]. This is challenging for the formulation of new drugs e.g., for photodynamic therapy.…”

“…Furthermore, porphyrin monomerization is essential to achieve biocompatible drug formulations of high bioavailability and low toxicity [8]. Such disaggregation can be accomplished by changing the polarity of the media by using, e.g., co-solvents or surfactants [8,9], which also makes these systems suitable for the design and development of optoelectronic devices (e.g., organic solar cells and electrochemical and optical sensors) [6].…”