title: Triplet behavior in weakly coupled chromophors in covalent pyridyl porphyrin-polymer systems.
abstract: The photophysical properties of the 5-(4-pyridyl)-10,15,20-tri(4-methyloxyphenyl)porphyrins covalently linked to polyethylene glycol - PEG of different molecular weights (35000, 20000 and 8000) dissolved in dimethylsulfoxide were studied. The singlet and triplet states of the porphyrin species behavior were discussed in terms of fluorescence and thermal relaxation processes. The absorption, fluorescence and photothermal experiments showed that in the porphyrins linked to the PEG systems in dimethylsulfoxide the dye moieties occur in weakly interacting dimers. The triplet state enhancement in the 5-(4-pyridyl)-10,15,20-tri(4-methyloxyphenyl)porphyrins covalently linked to PEG was discussed. It was shown that even that the weak interaction of the porphyrin species in the covalent systems with PEG is not detectable by the absorption and only slightly by fluorescence, it is possible to be performed by the complementary spectroscopic methods like photoacoustics and photothermal time resolved spectroscopy.
authors: Institute of Physics, Poznan University of Technology, Nieszawska 13A, 60-965 Poznań, Poland.
authors: Aleksandra
authors: A
authors: Siejak
authors: Danuta
authors: D
authors: Wróbel
authors: Barbara
authors: B
authors: Laskowska
authors: Yuri S
authors: YS
authors: Avlasevich
mesh_terms: D000042:Absorption; D004396:Coloring Agents / Q000138:chemical synthesis / Q000737:chemistry*; D006860:Hydrogen Bonding; D008954:Models, Biological; D010777:Photochemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011725:Pyridines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013818:Thermogravimetry / Q000379:methods
chemical_list: D004396:Coloring Agents; D011108:Polymers; D011166:Porphyrins; D011725:Pyridines; D011092:Polyethylene Glycols; C023666:pyridine