Luminescence of free bases of complexonate-substitutedtetraphenylporphyrin

Due to theunique properties, porphyrins are used in various fields including organic light-emitting diodes creation. At present, organic light-emitting diodes (OLEDs) are a most perspective technology of modern screen creation. One of perspective class of substances, which can be used as phosphorescence emitter in OLEDs, is complexes of porphyrins with platinum(II) and palladium(II). These substances phosphoresce at room temperature in solutions and in solid matrix with quantum yield of radiation to 0.9. Other porphyrin complexes with heavy atoms can possess intense phosphorescence, too. Earlier in our works intense phosphorescence (λ=765 nm, φ=0,7 in CHCl₃) of tetraphenylporphyrin with rare-earth ion Lu(III) in the centre of the macrocycle under 77K was demonstrated. Phosphorescence for the complex of Zn(II) with Lu(III) and complexonate-substituted TPP at room temperature with a small quantum yield was obtained which the unsubstituted complex lacks. So, the problem of heteroatom substitute-complexonate influence on photonics of similar compounds in the view of more effective emitter receiving deserves consideration. In this work the objects are free bases of aminoderivative of tetraphenlporphyrin with aliphatic hydrocarbon (C17H35), free complexon (ethylene diamine tetraacetate (EDTA) or diethylene triamine pentaacetate (DTPA)) or corresponding Lu(III) complexonate as substitute. The substances were studied in comparison with the well-studied unsubstituted tetraphenylporphyrin (H₂TPP). Ethanol was used as a solvent. Substitute introduction changes absorbance spectra insignificantly. This fact evidences the absence of macrocycle-amides coupling. Fluorescence spectra of all substances both at room temperature and at 77K have two vibration maxima (650 and 716 nm). Fluorescence quantum yield at 298K forms 3-6%, under cooling to liquid nitrogen temperature fluorescence efficacy shows 30-40% increase. Phosphorescence in area 850 nm that is relational to unsubstituted TPP phosphorescence is observed only for complexonate-substituted substances. Long-live radiation contains radiation from S₁- (delay fluorescence), Т ₁-state of molecule and Т ₁-state of photoproduct. The structure of photoproduct can be concatenated with photocation formation in frozen solutions. This assumption is confirmed by localization of protonated form phosphorescence maxima in area 785 nm. Total quantum yield of long-live radiation exceeds phosphorescence quantum yield of unsubstituted TPP in more than two orders of magnitude. Under 400 nm excitation short-wave long-live radiation is taken. This fact gives a chance of blue-emitting phosphor creation. Subsidiary research is necessary for short-wave long-live radiation formation mechanism ascertaining and complexonate structure influence on triplet-state settling different channels ratio

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