Theoretical Modeling of TPPS4 J-Aggregates

R. Augulis; J. Tamulienė; Arvydas Tamulis; R. Rotomskis

doi:10.4028/www.scientific.net/SSP.97-98.225

Paper Titles

Cylindrical Aggregates of TDBC: Linear and Nonlinear Optical Properties Versus Morphology
p.201

Reaction Dynamics and Applications in Patterning of Bisthienylcyclopentene-Based Photochromic Switches
p.207

Modelling Evolution of Nanostructures in Lateral Etching Processes
p.215

The Polar Sulfonic Groups Influence on Structure of Self-Assembled Tetrapyrrolic Molecules
p.221

Theoretical Modeling of TPPS₄ J-Aggregates
p.225

Basic Self-Formation Processes in the Technologies of the Integrated Circuits
p.229

Modelling Geometry of Technological Masks in Lateral Etching Processes
p.235

Self-Formation of Properties of the Mechanical System in Machining
p.239

Self-Assembly of a Synthetic Opal Infiltrated with Liquid Crystal Like Photonic Crystal
p.245

HomeSolid State PhenomenaSolid State Phenomena Vols. 97-98Theoretical Modeling of TPPS4 J-Aggregates

Theoretical Modeling of TPPS₄ J-Aggregates

Abstract:

The mechanism and conditions of meso-tetra (4-sulfonatophenyl) porphine (TPPS₄) molecular aggregate formation and their geometrical structure are investigated by methods of molecular mechanics and quantum chemistry. J- type aggregates are formed of zwitterionic forms of TPPS₄ via interaction of their positively charged porphyrin rings and negatively charged SO₃ - groups. According to ab initio and PM3 calculations it was found that TPPS₄ zwitterion has asymmetrical structure (parts of porphyrin ring are asymmetrically bent out of plane), although the porphyrin ring of TPPS₄ molecule in neutral aqueous solution (at pH 7) is flat and the planes of phenyl rings are nearly perpendicular to the porphyrin plane. We propose that asymmetrical porphyrin rings are able to form bent threads. The thread is bent approx. 5° for each monomer, so approximately 60 monomers should form the loop (diameter ~20 nm).